JPH07315187A - Control of automatic brake control system - Google Patents

Abstract

PURPOSE:To prevent the useless automatic braking work and reduce the noise and energy consumption by stopping the automatic braking work in the case when a driver operates a foot brake and actuates ABS in accordance with this operation even when an automatic brake working condition is established. CONSTITUTION:An automatic brake control unit 22 and an ABS control unit 27 are provided, and an automatic brake holding part 62 to which signals of an automatic brake working state and an ABS working state of a duty output part 61 are input is provided. When the ABS working signal is input during automatic brake work, holding of its braking pressure is commanded to the duty output part 61. Additionally, an automatic brake stop part 63 to which the signals of a state where a condition of the automatic braking work is established and the ABS working state at a brake switch 53 and an approach prediction part 55 is provided, and at the time when the automatic brake working condition is established, a switch signal by foot brake operation is input and the ABS working signal is input, then automatic brake working stop is commanded to the duty output part 61.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an automatic braking device for automatically braking a vehicle such as an automobile to prevent a collision or the like. Regarding measures when operating.

[0002]

2. Description of the Related Art Recently, as a safety measure for a brake system of a vehicle, an ABS device for preventing wheel lock during braking and an automatic brake device for preventing collision by judging approaching an object while traveling are proposed. Has been done. Since the automatic brake device may come into contact when the braking force is insufficient even if the driver operates the foot brake, the automatic brake device is controlled to operate automatically regardless of whether the foot brake is operated. In addition, the ABS device may lock the wheels due to an excessive braking force not only when the driver operates the foot brake but also when the automatic brake is operated.
It is possible to operate the ABS in both the foot brake operation and the automatic brake operation.

Therefore, in a brake system equipped with an ABS device and an automatic braking device, a foot brake operation is performed by a driver when an automatic braking operation condition is satisfied,
When the ABS is operated based on the foot brake operation, it is expected that the automatic brake will also be operated redundantly. By the way, in the ABS operation at the time of operating the foot brake, the vehicle is appropriately decelerated and controlled by depressurizing, holding or increasing the brake pressure. Therefore, it is useless to further pressurize the brake pressure by automatically operating in this state. . Further, it is necessary to improve this point because an unnecessary automatic brake operation causes operating noise and causes a defect such as impairing the durability of the system.

Conventionally, as for the control of the brake system including the ABS device and the automatic brake device, there is a prior art disclosed in, for example, Japanese Patent Laid-Open No. 50908/1993. In this prior art, when ABS is operated when the vehicle is automatically braked by increasing the brake pressure by the automatic brake operation,
It is shown that the pressure increase of the automatic brake is temporarily stopped to ensure safety.

[0005]

By the way, in the above-mentioned prior art, since it is a countermeasure when the ABS is operated during the automatic brake operation, A at the time of operating the foot brake is required.
It cannot be applied as a countermeasure when the automatic braking is activated during BS operation.

In view of the above points, the present invention has an object to prevent unnecessary automatic brake operation during ABS operation during driver's foot brake operation.

[0007]

In order to achieve this object, the present invention provides an automatic electrical system when there is a possibility of contact with a vehicle brake device which arbitrarily generates a brake pressure by the foot brake operation of a driver. When an automatic brake hydraulic unit that operates a brake is provided in series with an ABS hydraulic unit that electrically operates an ABS when there is a possibility of wheel lock, and the prescribed conditions are satisfied regardless of whether or not the foot brake is operated. In the automatic brake device that controls the automatic brake operation so that the ABS operation is performed in both the foot brake operation and the automatic brake operation, the foot brake operation is performed by the driver even if the automatic brake operation condition is satisfied. The feature is that when the ABS is operated based on the brake operation, the automatic brake operation is stopped. That.

In the present invention, the approach to the object during traveling can be judged by various input information, and the automatic brake operating condition may be established when there is a possibility of this contact. The automatic brake hydraulic unit may be configured to enable the foot brake or to automatically control the pressurization, depressurization and holding of the brake pressure by an electric signal. When stopping the automatic brake operation, at least the automatic brake hydraulic unit may be controlled so as to be kept in the foot brake enabled state.

[0009]

In the present invention according to the above control method, the brake pressure is arbitrarily generated by the foot brake operation of the driver to decelerate and brake. Further, if there is a possibility of contact with an object during traveling regardless of whether or not the foot brake is operated, the automatic brake hydraulic unit controls the brake pressure to automatically brake the vehicle, thereby preventing a collision. In both cases of foot brake operation and automatic brake operation, when the danger of wheel locking is caused by the braking force due to the brake pressure, the ABS hydraulic unit operates ABS to prevent wheel locking. Further, even if the automatic brake operating condition is satisfied due to the possibility of contact with an object while traveling, the foot brake operation is performed by the driver, and when the ABS operation is performed based on the foot brake operation, the brake pressure is reduced, held or increased. The vehicle is properly decelerated by pressurizing.
Therefore, in this case, by stopping the automatic brake operation, unnecessary automatic brake operation can be prevented, operation noise can be reduced, and system durability can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. An outline of the drive system and the brake system of the vehicle will be described with reference to FIG. First, a vehicle has left and right front wheels 1L, 1R and rear wheels 2L, 2R. As a drive unit A, an engine 3 passes through a clutch 4, a transmission 5, a propeller shaft 6, a differential unit 7, and an axle 8, for example, left and right. Rear wheel 2
It is configured to transmit to L and 2R. The throttle valve 10 of the engine 3 is provided with a throttle control unit 12 via an actuator 11 so as to control the throttle during traction control or cruise control.

The brake device B is equipped with an automatic brake device 20 and an ABS device 25. That is, the master cylinder 14 having the brake pedal 13 and the ABS hydraulic unit 26 are connected in series to the automatic brake hydraulic unit 21, and the ABS hydraulic unit 26 is connected to the left and right front wheels 1L and 1R and the rear wheel 2 by the brake line 15.
It communicates with the L and 2R wheel cylinders 16. Then, a signal from the automatic brake control unit 22 is output to the hydraulic unit 21 for automatic brake operation, and a signal from the ABS control unit 27 is output to the ABS hydraulic unit 26 for ABS operation.

The automatic brake hydraulic unit 21 will be described with reference to FIG. Explaining one brake line 30 of two systems that communicates from the master cylinder 14 having the brake pedal 13 to the ABS hydraulic unit 26, a pressure reducing solenoid valve 31 and a relief valve 32 are provided in this brake line 30. In addition, the master cylinder 14
The pipeline 33 from the oil reservoir 17 is communicated with the oil pump 35 driven by the motor 34 to generate hydraulic pressure. The discharge side pipe line 36 of the oil pump 35 communicates with the relief valve 37 through the check valve 38 and the accumulator 39, and further has the pressurizing solenoid valve 40 and communicates with the brake pipe line 30. It is possible to pressurize the brake pressure.

The depressurizing solenoid valve 31 is in a communication position when it is OFF, and is switched to a shut-off position when it is ON. On the contrary, the pressurizing solenoid valve 40 is in the shut-off position when it is OFF and switches to the communication position when it is ON. A hydraulic pressure sensor 41 for detecting pedal pressure, brake pressure, and accumulator pressure is provided, and a pressure switch 42 is provided. The pressure switch 42 drives the motor 34 at the set lower limit pressure, stops the motor 34 at the set upper limit pressure, operates the oil pump 35, and accumulates pressure in the accumulator 39. On the other hand, the pressure reducing solenoid valve 31 and the relief valve 32 are similarly provided in the other two brake lines 43 of the system, and the pump side line 36 is provided.
A line 44 branching from has a pressurizing solenoid valve 40 and communicates with its brake line 43.

In this way, when the pressurizing solenoid valve 40 is turned off and the depressurizing solenoid valve 31 is turned off to establish communication, a normal braking state is established, and a brake pressure is arbitrarily generated by the foot brake operation of the brake pedal 13 for braking. To do. When the pressure-reducing solenoid valve 31 is also turned on in this state to shut off, the brake pressure is confined in the brake line 15 and kept constant. On the other hand, the pressure reducing solenoid valve 31 O
When the pressurizing solenoid valve 40 is turned on at a predetermined duty ratio at this time by shutting off with N, the accumulator pressure or pump pressure is gradually introduced into the brake pipe line 15 to pressurize it. Further, when the pressurizing solenoid valve 40 is turned off to shut it off and the depressurizing solenoid valve 31 is turned off at a predetermined duty ratio at this time, the brake pressure in the brake line 15 is gradually released to reduce the pressure.

The automatic brake control unit 22 will be described with reference to FIG. First, a CCD camera 50, a vehicle speed sensor 51, an automatic brake selection switch 52, a hydraulic pressure sensor 41, and a brake switch 53 are provided, and signals from these sensors and switches are input to the control unit 22. The control unit 22 has a CCD camera 50, a signal from the automatic brake selection switch 52, and an approach prediction unit 55 to an object to which the vehicle speed V is input. For example, the relative distance L to the preceding vehicle and the relative speed Vs are calculated to determine whether or not there is a possibility of approaching the object, and when there is a possibility of contact, an approach warning signal is output to the alarm 56. When there is no possibility of approach, or when the driver performs a brake operation to avoid contact by an approach alarm, the duty output unit 61 causes the pressurizing solenoid valve 40 and the depressurizing solenoid valve 31 to be OF.
Output F signal.

When there is a possibility of contact regardless of whether or not the brake is operated, the target acceleration setting unit 57 sets a negative target acceleration Gt for avoiding contact. The vehicle speed V is input to the actual acceleration calculating section 58, and the vehicle speed V is differentiated to calculate the actual acceleration G. The negative target acceleration Gt and the actual acceleration G are input to the deviation calculation unit 59, and the deviation ΔG between the two is calculated as ΔG
= Gt-G This deviation ΔG, actual acceleration G
Is input to the determination unit 60 for acceleration, depressurization, etc., and the acceleration, depressurization, etc. are determined by the preset control dead zone a, the deviation ΔG, and the sign of the actual acceleration G. That is, the absolute value of the deviation | ΔG
If | is within the control dead zone a, it is determined to hold. Further, when the absolute value of the deviation | ΔG | is outside the control dead zone a and ΔG> 0, that is, Gt> G, the actual acceleration is negative and smaller than the target acceleration, so the pressure reduction is determined. ΔG <0, that is, Gt <G
When <0, the actual acceleration is negative and is larger than the target acceleration, so pressurization is determined, and when the actual acceleration is positive, it is determined that deceleration has not been performed.

These judgment signals before pressurization, pressure reduction, holding or deceleration, deviation ΔG, and actual brake pressure Pb of the hydraulic pressure sensor 41 are input to the duty output section 61, and in the case of holding, an OFF signal to the pressurizing solenoid valve 40. To output an ON signal to the pressure reducing solenoid valve 31. When the pressure is increased or decreased, the target instruction pressure Pt corresponding to the deviation ΔG is set, and the deviation ΔP between the target instruction pressure Pt and the brake pressure Pb is, for example, PID-controlled to determine the duty ratio D. In the case of pressurization, an ON signal is output to the depressurizing solenoid valve 31, an ON signal of the duty ratio D is output to the pressurizing solenoid valve 40, and the depressurizing solenoid valve 40 has a predetermined duty ratio Di before deceleration. Output the initial value. In the case of depressurization, an OFF signal is output to the pressurizing solenoid valve 40, and an OFF signal of the duty ratio D is output to the depressurizing solenoid valve 31.

Next, the control system in the case where the automatic brake and the ABS operate in duplicate will be described. First, the duty output unit 61 has an automatic brake holding unit 62 to which signals of an automatic brake operating state and an ABS operating state are input.
When the ABS operation signal is input during the automatic brake operation regardless of whether or not the brake operation is performed, the duty output unit 61 is instructed to maintain the brake pressure with emphasis on the stability of the vehicle.

Further, the brake switch 53 and the approach predicting section 5
The automatic brake stopping unit 63 receives a signal indicating that the automatic brake operating condition is satisfied in 5 and the ABS operating state.
When the switch signal by the foot brake operation is input when the automatic brake operation condition is satisfied and the ABS operation signal is further input based on the foot brake operation, the duty output section 61 is automatically operated to prevent unnecessary automatic brake operation. It is configured to command brake deactivation.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, in step S1, initialization is performed when the ignition switch is turned on. Then, in step S2, the operation of the automatic brake selection switch 52 is checked, and if the switch is OFF, step S3
Go to and set the foot brake movable. That is, the pressure solenoid valve 40 is turned off to shut off the pressure reducing solenoid valve 3
When the brake pedal 13
When the brake pressure is generated in the master cylinder 14 by operating the, the brake pressure is applied to the brake pipe lines 30, 43, AB.
Wheel cylinders 16 for the left and right front wheels 1L, 1R and rear wheels 2L, 2R via the S hydraulic unit 26 and the brake pipe 15.
It is introduced and braked.

When the switch is ON, the routine proceeds to step S4 to check the vehicle speed V, and when the vehicle is traveling, it proceeds to step S5 to check the presence of a preceding vehicle. If the relative distance L is less than the set value Ls and there is a preceding vehicle, In step S6, the relative speed Vs obtained by subtracting the own vehicle speed from the preceding vehicle speed is checked. When the relative speed Vs decreases, the possibility of contact is determined, and an approach warning is given in step S7. Under other conditions such as vehicle stop, relative distance Ls is large and there is no preceding vehicle, and relative speed Vs is large and the vehicle is separated, it is determined that there is no possibility of contact and the automatic brake operation flag is set to 0 in step S8. Then, in step S9, automatic brake ABS is performed.
By setting the corresponding hydraulic pressure holding control flag to 0, the automatic brake hydraulic unit is set to the foot brake operable state.

After the approach warning, the negative target acceleration Gt, the actual acceleration G, and the deviation ΔG between the two are calculated in step S10.
Then, in step S11, the brake switch 53 is checked, and if there is no brake operation, the process proceeds to step S12 and the automatic brake operation flag is set to 1. In the next step S13, it is determined whether or not the ABS operation flag is present in order to determine whether or not the ABS control unit 27 is operating. If the ABS operation flag is 1, step S1
By setting the automatic brake ABS-compatible hydraulic pressure holding control flag to 1 in 4, the brake pressure at this time is temporarily held.

On the other hand, when the ABS operation flag is 0 and the ABS is not operated in step S13, the process advances to step S15 to set the automatic brake ABS-corresponding hydraulic pressure holding control flag to 0, and the automatic braking is restarted.

When it is determined in step S11 that the brake switch 53 is ON, the process proceeds to step S16.
Determine whether the automatic brake activation flag is present. Step S
When it is determined in 16 that the automatic brake is operating, the process proceeds to step S13, and when ABS is operating, the above-described control for temporarily holding the brake pressure at this time is performed.

On the other hand, if the automatic brake is released in step S16 and it is determined that the driver is operating the foot brake, the process proceeds to step S17, it is determined whether or not the ABS is operated, and the automatic brake operation is maintained in the suspended state when the ABS is operated.

If it is determined in step S17 that the ABS is not in operation, the process proceeds to step S18, the automatic brake operation flag is set to 1, and the automatic brake operation is performed.

The automatic brake control will be described with reference to the flowchart of FIG. First, in step S21, the negative target acceleration Gt, the actual acceleration G, and the deviation ΔG between the two are read, and the deviation ΔG is compared with the control dead zone a in step S22. Therefore, in the initial stage of the automatic brake operation, | ΔG |> a, so the process proceeds to step S23, and the sign of the deviation ΔG is checked. At this time, since the actual acceleration G is small and ΔG <0, the process proceeds to step S24, and the sign of the actual acceleration G is checked.
If there is no brake operation, the actual acceleration is positive, so
In step S25, the brake pressure is controlled to the initial value.

Therefore, in the automatic brake hydraulic unit 21, the pressure reducing solenoid valve 31 is turned on and the brake pipe lines 30 and 43 are cut off from the master cylinder 14. At this time, the pressurizing solenoid valve 40 is set to the predetermined duty ratio Di.
Is turned on and the accumulator pressure or pump pressure is introduced into the brake lines 30 and 43.
Left and right front wheels 1L, 1R and rear wheel 2 from the hydraulic unit 26
Brake line 1 to the wheel cylinder 16 of L and 2R
An initial brake pressure is generated at 5, and deceleration starts.

After that, a negative actual acceleration G is generated, and when the actual acceleration G is larger than the negative target acceleration and ΔG> 0, the process proceeds from step S23 to step S26 to control the pressure reduction. That is, the pressurizing solenoid valve 40 is turned off, the introduction of accumulator pressure and the like is stopped, and the pressure reducing solenoid valve 31
Is turned off at the duty ratio D based on the deviation ΔG, and the brake pressure in the brake pipe lines 30, 43 is gradually discharged to the oil reservoir 17 via the master cylinder 14. Therefore, the brake pressure in the brake line 15 is reduced, and the negative actual acceleration G is reduced. If the negative actual acceleration G is smaller than the negative target acceleration and ΔG <0, step S24 is performed.
To step S27, the pressurization is controlled. That is, the pressure reducing solenoid valve 31 is turned on to shut off, and at this time, the pressure increasing solenoid valve 40 is turned on at the duty ratio D based on the deviation ΔG to gradually introduce the actuator pressure and the like. Therefore, the brake pressure in the brake pipe 15 is increased, and the negative actual acceleration G
Grows larger.

Further, when the absolute value of the deviation | ΔG | falls within the control dead zone a, the routine proceeds from step S22 to step S28 to perform the holding control. That is, the pressurizing solenoid valve 40 is OF
F and pressure reducing solenoid valve 31 is turned on, and brake line 1
The brake pressure of 5 is held constant by containment. Therefore, the actual acceleration G is held in a state of substantially matching the negative target acceleration Gt. The vehicle is automatically braked by such a brake pressure control, and in this case, the actual acceleration G is feedback-controlled so as to follow the negative target acceleration Gt and increase, so that the vehicle can appropriately avoid contact. The vehicle is decelerated, which prevents contact with the preceding vehicle.

During the automatic brake operation, the ABS
The control unit 27 determines whether or not the wheels are locked, and if the braking force in this case causes a risk of locking the wheels, the ABS is activated. Therefore, when the ABS is operated during the automatic brake operation as shown in FIG. 6A, the process proceeds from step S13 to step S14 in the flowchart of FIG. 4 to perform the holding control. That is, as described above, the pressurizing solenoid valve 40 is turned off and the depressurizing solenoid valve 31 is turned on, and the brake pressure in the brake conduit 15 is temporarily held at the brake pressure P1 at this time as indicated by the alternate long and short dash line. . Therefore, it is possible to prevent the brake pressure on the automatic brake side from unnecessarily increasing due to the influence of the ABS operation. Further, in the ABS operation, the brake pressure P1 that is held is used as a base to control the pressure reduction, holding, and pressure increase with a good response, so that the wheel lock is accurately prevented. Further, after the ABS operation is completed, step S13
From step S15 to step S15, the automatic braking is restarted, but the brake pressure P1 held at this time is quickly returned to the automatic braking operation.

On the other hand, when an automatic braking operation condition is established due to the possibility of contact with an object and an approach alarm is issued, FIG.
As shown in (b), when the driver brakes the foot brake to generate a predetermined brake pressure P2 and the vehicle is decelerated and the ABS is actuated against the braking force in this case, the process proceeds from step S16 to step S17 in the flowchart of FIG. To keep the automatic brake operation stopped. That is, both the pressurizing solenoid valve 40 and the depressurizing solenoid valve 31 are turned off.
Then, the normal brake operation state is maintained. Therefore, the brake pressure P2 is reduced, held or increased by the brake operation and the ABS operation so that the vehicle is appropriately controlled to decelerate and the possibility of contact tends to be avoided. At this time, unnecessary pressurization is performed by the automatic brake operation. Is prevented. After the ABS operation is completed, if the automatic brake operation condition is satisfied regardless of the driver's brake operation, the process proceeds from step S17 to step S18, and the automatic brake operation is performed as indicated by a chain double-dashed line.

[0033]

As described above, according to the present invention,
In a system equipped with an automatic braking device and an ABS device in a vehicle braking device, even if the automatic braking operation condition is satisfied, the driver operates the brakes, and if the ABS operation is performed based on this braking operation, the automatic braking operation is stopped. As described above, unnecessary automatic brake operation can be prevented. In addition, operating noise and unnecessary energy consumption are reduced, and the durability of the system is improved. When the automatic brake operation is stopped, the normal braking state is controlled, so the control is very simple.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment suitable for a control method for an automatic braking device according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic unit of the automatic brake device.

FIG. 3 is a diagram schematically showing a vehicle drive device and a brake device.

FIG. 4 is a flowchart showing overall control.

FIG. 5 is a flowchart showing automatic brake control.

FIG. 6 is a diagram showing a state of automatic brake operation, ABS operation, and the like.

[Explanation of symbols]

 B Brake device 20 Automatic brake device 21 Automatic brake hydraulic unit 22 Automatic brake control unit 25 ABS device 26 ABS hydraulic unit 27 ABS control unit 63 Automatic brake stop unit

Claims (2)

[Claims] 1. A possibility of wheel locking in a vehicle brake device which generates a brake pressure at any time by a driver's foot brake operation and an automatic brake hydraulic unit which electrically automatically brakes when a collision may occur. If there is an ABS hydraulic unit that is electrically ABS operated in series, and if the predetermined conditions are satisfied regardless of whether or not the foot brake is operated, automatic braking is activated,
In an automatic brake device that controls to operate ABS during both foot brake operation and automatic brake operation, the driver performs foot brake operation even if the automatic brake operation condition is satisfied, and ABS operation is performed based on this foot brake operation. In this case, the method for controlling the automatic braking device is characterized in that the automatic braking operation is stopped. 2. The automatic brake hydraulic unit is configured to automatically control the pressurization, decompression and holding of the foot pressure or the brake pressure by operating the pressurizing solenoid valve and the depressurizing solenoid valve. 2. The method for controlling an automatic brake device according to claim 1, wherein the pressurizing solenoid valve and the pressure reducing solenoid valve are kept in a foot-brake enable state in the case of stopping.