JP2000016275A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the gripping forces of tires to effectively actuate a brake assist device in a vehicle having a brake assist system for use in emergencies by restraining excessive steering in an emergency, as when an obstacle should be avoided with the vehicle speed low. SOLUTION: When vehicle speed is smaller than a predetermined vehicle speed and the steering angular velocity of a steering wheel is smaller than a predetermined angular velocity, a controller 40 controls an assist device 66 for power steering to reduce its assist force, and turns an alarm buzzer on. When the steering angular velocity of the steering wheel is not smaller than the predetermined angular velocity, that is, when an obstacle or the like cannot be avoided while the assisting force produced by the assist device 66 is kept small, then control using the normal assist device 66 is restored to allow the driver to steer the vehicle comfortably, rapidly, and greatly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle control apparatus provided with a power steering device for assisting a driver's steering force and a brake assist device for assisting a driver's brake pedal force. Belongs to the field of technology.

[0002]

2. Description of the Related Art In recent years, devices for assisting various operations of a driver who drives a vehicle have been developed and mounted. One of the devices is that a driver performs steering operation.
There is a power steering device that assists the steering force of the driver. This power steering device, for example,
When the vehicle speed is low, the assist force is relatively large,
When the vehicle speed is high, by providing a predetermined amount of assist force according to the speed of the vehicle, such as making the assist force relatively small, the burden on the driver can be reduced, and the driver can more safely and comfortably. This enables steering operation.

As another assisting device, for example, as disclosed in Japanese Patent Application Laid-Open No. 8-34326, a driver depresses a brake pedal to decelerate the vehicle.
There is a brake assist device that assists the braking force when trying to stop. This brake assist device is intended to improve running stability by obtaining a sufficient braking force when necessary. The above-mentioned publication discloses an urgency level for judging an urgency level from operation states of brakes, steering, and the like. A judgment means and a physical risk judgment means for judging a collision risk based on a distance and a relative speed with respect to the obstacle are provided, and the risk of collision with the obstacle is determined by the physical risk judgment means. When it is determined that there is an emergency, and when it is determined by the urgency determination means that there is an urgency in the operation of the driver, a so-called full brake that automatically obtains the maximum braking force is performed. The disclosed brake assist device is disclosed.

[0004]

In an emergency such as when the driver avoids an obstacle, the steering operation and the brake operation are mainly performed.
In this case, as described above, when the normal vehicle speed is high, the assist force of the power steering device is relatively small, and the steering operation is relatively heavy, so that even in an emergency, the stability of the vehicle, that is, The grip force of the tire on the road surface is maintained, and good steering performance and braking performance are ensured. In such a state, the brake assist device operates effectively.

On the other hand, when the vehicle speed is low, as described above, the assisting force of the power steering device is relatively large and the steering operation is relatively light, so that a large and sudden steering operation is performed in an emergency. There are cases.

However, when such a large and steep steering operation is performed, the grip force of the tire on the road surface is lost, and the steering performance and the braking performance are reduced, and in such a state, the brake assist device operates. Even
In many cases, sufficient braking force cannot be obtained.

Accordingly, the present invention reduces the assist force of the power steering device to suppress excessive steering by reducing the assist force of the power steering device when the vehicle speed is low in an emergency such as avoiding an obstacle. It is an object to secure the brake assist device so that the brake assist device operates effectively.

[0008]

Means for Solving the Problems In order to solve the above problems, the following means are used.

First, an invention according to claim 1 of the present application (hereinafter referred to as a "first invention") is a power steering device for assisting a driver's steering force, and a vehicle speed detecting means for detecting a vehicle speed. A power steering assisting force adjusting means for adjusting the assisting force of the power steering device according to the vehicle speed; and a brake assisting means for assisting a braking force generated by operating a brake pedal. In operation, control means is provided for reducing the assisting force of the power steering device when the vehicle speed is low as compared with the assisting force when the vehicle speed is high.

Next, a second aspect of the invention (hereinafter referred to as a "second invention") is a power steering apparatus for assisting a driver's steering force, a vehicle speed detecting means for detecting a vehicle speed, and a vehicle speed detecting means. A power steering assisting force adjusting means for adjusting the assisting force of the power steering device according to the above, and a brake assisting means for assisting a braking force generated by operation of a brake pedal. When the vehicle speed is equal to or lower than a predetermined vehicle speed, a control means for reducing the assisting force of the power steering device is provided.

Further, the invention according to claim 3 (hereinafter referred to as “third invention”) is characterized in that in the first or second invention,
The control means stops the control for reducing the assisting force of the power steering device when at least one of the steering angle of the steering or the steering angular velocity becomes a predetermined value or more.

The invention according to claim 4 (hereinafter referred to as "the invention")
This is referred to as a "fourth invention." The present invention is characterized in that, in the first or second invention, a notifying means for notifying the driver that the assisting force of the power steering device has been reduced is provided.

According to the first to fourth inventions, the following effects can be obtained.

According to the vehicle control device of the first invention, when the brake assisting device is operated, the assisting force of the power steering device when the vehicle speed is low is made smaller than the assisting force when the vehicle speed is high. Means, the assisting force of the power steering device is smaller when the vehicle speed is low than when the vehicle speed is high, so that excessive driver steering at low vehicle speed is achieved. , The grip force of the tire on the road surface can be secured, and as a result, the brake assist device can operate effectively.

Next, according to the vehicle control device of the second invention, when the brake assisting device is operated, if the vehicle speed is equal to or less than the predetermined vehicle speed, the control device for reducing the assisting force of the power steering device is provided. During operation of the brake assisting means, when the vehicle speed is equal to or lower than a predetermined vehicle speed, the assisting force of the power steering device is reduced. As a result, excessive steering of the driver when the vehicle speed is equal to or lower than the predetermined vehicle speed is suppressed, and the tire road surface is suppressed. Grip force against
The brake assist device can operate effectively.

Further, according to the vehicle control apparatus of the third invention, the control means reduces the assisting force of the power steering apparatus when at least one of the steering angle of the steering or the steering angular velocity becomes a predetermined value or more. Therefore, if a large steering operation of a predetermined value or more is performed in a state where the assisting force of the power steering device is reduced, the control returns to the normal control of the power steering device and the driver's operation is stopped. The steering operation is assisted, and the steering can be made large and easy.

According to the vehicle control device of the fourth invention, the notifying means for notifying the driver that the assisting force of the power steering device has been reduced is provided, so that the assisting force of the power steering device is provided to the driver. Recognizing that the driver has become smaller, the driver's discomfort when the assisting force is small can be reduced.

[0018]

Embodiments of the present invention will be described below.

As shown in FIG. 1, a vehicle braking system according to this embodiment is basically composed of a brake pedal 1 which is depressed by a driver and a booster 2 which is depressed by the pedal 1. , A brake device 5 including a disk rotor 5a and a caliper 5b provided on each of the wheels 4... 4 (only one is shown), and a brake device for controlling the master cylinder pressure. A wheel cylinder 7 that applies the braking force to the wheels 4 by operating the brake device 5 when supplied via the system 6.

Here, the schematic configuration of the booster 2 will be described. As shown in FIG. 2, the booster 2 has a diaphragm 11 inside a case 11 and a negative pressure chamber 13 and an atmosphere chamber 14. When the brake pedal 1 is depressed, the first push rod 15 connected to the pedal 1
The diaphragm 12 and the diaphragm 12
Is configured to press the piston 3a of the master cylinder 3 via the second push rod 16 attached to the master cylinder 3.

Normally, a boost pressure (negative pressure) from the engine is introduced into both the negative pressure chamber 13 and the atmosphere chamber 14 to maintain the pressure on both sides of the diaphragm 12 in a balanced state, and to apply a brake. When the pedal 1 is depressed, the valve body 15a provided on the first push rod 15 separates from the valve seat 11a on the case 11 side, thereby introducing atmospheric pressure into the atmosphere chamber 14 and causing the diaphragm 12 to brake. A force is applied in the direction in which the pedal 1 is depressed, and this force is added to the depressing force applied to the brake pedal 1 and transmitted to the piston 3a of the master cylinder 3.

As shown in FIG. 1, the braking device incorporates an anti-skid brake system (hereinafter, referred to as ABS) and a brake assist system (hereinafter, referred to as BAS).

As components of these systems, a cut valve 21 disposed on the master cylinder 3 side of the brake system 6 to open or shut off the system 6 and a downstream side thereof (wheel cylinder 7 side). A pressure increasing valve 22 that opens or shuts off the brake system 6, and a pressure reducing valve 25 that is further arranged on a pressure reducing line 24 branched from the downstream side to an oil pan 23 to open or shut off the pressure reducing line 24. Is provided.

Further, between the cut valve 21 and the pressure increasing valve 22 in the brake system 6, a pressure increasing line 2 is provided.
A pump 28, which is driven by a motor 27 and supplies the brake fluid from the oil pan 23 to the brake system 6, is provided on the line 26. The orifice 29
An orifice switching valve 29 is provided for switching between a state where the diaphragm is narrowed by a and a state where the diaphragm is not narrowed.

The master cylinder 3 is provided with a reservoir tank 30, and a brake fluid recovery pipe 31 is provided from the reservoir tank 30 to the oil pan 23.

A controller 40 for controlling ABS and BAS is provided. The controller 40 has wheel speed sensors 41... 41 (only one shown) for detecting the rotational speed (wheel speed) of each wheel 4. ),
A signal from a brake switch 42 for detecting depression of the brake pedal 1, a signal from an idle switch 43 for detecting depression of an accelerator pedal (not shown),
A vehicle speed sensor 44 for detecting a vehicle speed is input. A master cylinder pressure sensor 45 for detecting a master cylinder pressure generated in the master cylinder 3 for controlling the start of BAS operation described later. And a signal from the sensor 45 is also input to the controller 40.

Here, the operation of the ABS will be briefly described.
... When it is detected from the signal from 41 that there is a wheel whose wheel speed is unnaturally reduced with respect to the vehicle speed, the pressure reducing valve 25 is opened for that wheel to reduce the brake fluid in the wheel cylinder 7. The braking force is reduced by draining through the line 24, thereby eliminating or avoiding the skid condition, and if the wheel speed of the wheel increases due to the reduction of the braking force, the pressure reducing valve 25 is used.
At the same time, the pressure increasing valve 22 is opened, and the brake fluid is supplied from the pump 28 to the wheel cylinder 7 via the pressure increasing line 26 to increase the braking force. By repeating this in accordance with the wheel speed, control is performed such that a required braking force is obtained while preventing the skid state of the wheel.

In this embodiment, when the cut valve 21 is closed during the above-described ABS operation, the pulsation of the braking pressure generated on the wheel cylinder 7 side is transmitted to the brake pedal 1 and the driver feels discomfort. To prevent giving. Also, during the ABS operation, the orifice switching valve 29 on the pressure increasing line 26 is kept in a state where the line 26 is not throttled.

The operation of the BAS for an emergency will be briefly described. When the controller 40 determines that the brake assist means should be operated based on a signal from the master cylinder pressure sensor 45, Each wheel 4
With respect to... 4, by operating the drive motor 27 of the pump 28 in a state where the pressure increasing valve 22 is opened and the pressure reducing valve 25 is closed, The brake fluid is simultaneously supplied to the wheel cylinders 7... Of the wheels 4. 4, so that the vehicle as a whole can obtain a required braking force in an emergency.

In this case, the cut valve 21 on the brake system 6 is kept open, and the assist pressure by the brake fluid supplied from the pump 28 is added to the brake pressure from the brake pedal 1 or the master cylinder 3. However, the cut valve 21 may be kept closed during the brake assist.

The orifice switching valve 29
Usually, by adjusting the pressure increasing line 26 by the orifice 29a, the supply speed of the assist pressure is appropriately adjusted, and the braking by the driver despite the emergency is determined. When it is determined that the depression speed of the pedal 1 is not sufficient, the orifice 29a is removed to increase the assist pressure rising speed. Also, when it is determined that the driver does not press the brake pedal 1 sufficiently despite the emergency determination, the rotational speed of the pump driving motor 17 is increased to increase the braking force. The control for causing the control is also performed.

Further, the idle switch 43 is for performing control such as increasing the assist pressure when the accelerator pedal is erroneously depressed during a brake operation in an emergency. It is also possible to use a throttle opening sensor for detecting the degree.

On the other hand, as shown in FIG. 3, a power steering device 60 is provided at the front of the vehicle 50 to assist the steering force when the driver steers the steering wheel 61. The power steering device 60 includes a steering shaft 62 connected to the steering wheel 61, a steering rod 64 connected to left and right front wheels 63, 63, and a steering wheel 61.
Gearbox 6 that transmits the rotational displacement of the gear to steering rod 64
5 and a power steering assist device 66 that assists the steering force of the steering wheel 61 using hydraulic pressure or the like.

When the controller 40 receives signals from the vehicle speed sensor 44 and the like, the controller 40 transmits the signals to the assist device 66 based on these signals.
6 to output a control signal for controlling the operation of, for example,
The assist device 66 is controlled such that the assist force is reduced when the vehicle speed is high, and is increased when the vehicle speed is low.

A warning buzzer 67 is provided near the steering wheel 61. When the controller 40 controls the assist device 66 differently than usual, the warning buzzer 67 is simultaneously activated. It has become. Thereby, the driver is notified that the control by the assist device 66 has been performed,
Driver discomfort caused by such control can be reduced.

Next, an example of a specific operation of the BAS and power steering device 60 by the controller 40 according to the present embodiment will be described.

In this embodiment, it is determined whether the brake operation is for sports running on a winding road such as a mountain road or for emergency. I have. In this case, in both of the above brake operations, the stepping speed of the brake pedal is high, and the change in the master cylinder pressure at that time is as follows.

That is, as shown in FIG. 8, after the master cylinder pressure rises immediately after the start of depression of the brake pedal, the rate of increase decreases due to a response delay in the operation of the booster utilizing the boost pressure of the engine. When the booster starts to operate due to the boost pressure after the stagnation, the ascending rate increases again and rises in earnest. A point and an increasing inflection point occur. In the braking operation during sports running and the emergency braking operation, in particular, after the occurrence of the increasing inflection point, the rate of increase or the value of the master cylinder pressure corresponding to the stepping speed or the stepping amount of the brake pedal. Are remarkably different, and in the present embodiment, the above-described identification is performed by paying attention to this.

The flowchart of FIG. 4 shows the control operation in the embodiment. First, in step S1, a decrease counter Cdec for detecting the inflection point on the decreasing side of the master cylinder pressure used in the following control, The increment counter Cinc for inflection point detection is cleared to 0, and signals from the brake switch 42, the idle switch 43, and the master cylinder pressure sensor 44 shown in FIG.

In step S3, an increment dP (= P-P ') of the master cylinder pressure P detected by the sensor 44 in the present control cycle with respect to the value P' in the previous control cycle, and the increment thereof. The rising speed vP of the master cylinder pressure P obtained by dividing dP by the control cycle t is calculated.

Next, at step S4, the brake switch 4
2 is turned on, that is, whether the brake pedal 1 is depressed or not. If the brake pedal 1 is not depressed, the decrement counter Cdec and the increment counter Cinc are cleared again in steps S5 and S6, and the pump The driving motor 27 is kept OFF.

On the other hand, when the brake pedal 1 is depressed and the brake switch 42 is turned on, step S4
To execute step S7 to determine whether or not the motor 27 is OFF. Then, immediately after the brake pedal 1 is depressed, the motor 27 is in the OFF state. Therefore, in steps S8 and S9, the increase counter Ci is determined.
It is determined whether the values of nc and Cdec are 2 respectively.

These counters Cinc and Cdec are:
Immediately after the brake pedal 1 is depressed, the state is cleared to 0.
10 to compare the increment dP of the master cylinder pressure P obtained in the current control cycle with the increment dP 'obtained in the previous control cycle, and determine whether the current increment dP is smaller than the previous increment dP'. Is determined. If it is not smaller, the decrement counter Cdec is held at 0 in step S11.

On the other hand, as shown by reference numeral a in FIG. 5, when the present increment dP of the master cylinder pressure P is smaller than the previous increment dP ', 1 is added to a decrease counter Cdec in step S12 to thereby increase the value. Let the value be 1.
Also, in the next control cycle, if the increment dP obtained in that cycle is smaller than the previous increment dP ', the decrement counter Cd is again set in step S12.
1 is added to ec, and the value is set to 2.

In this manner, the current increment d is continuously obtained twice.
When P becomes smaller than the previous increment dP ', the rising speed of the master cylinder pressure P shifts from an increasing side to a decreasing side,
It is determined that the decreasing inflection point Xd of the master cylinder pressure P has occurred.

In this case, even if the present increment dP of the master cylinder pressure P once becomes smaller than the previous increment dP ',
The increment dP obtained in the next control cycle is the previous increment d.
When it becomes equal to or greater than P ', the decrease counter Cdec is cleared in step S11. Therefore, even if the increment dP obtained in the next cycle becomes smaller again than the previous increment dP', the decreasing inflection point Xd remains Without determining that it has occurred,
As described above, only when the current increment dP becomes smaller than the previous increment dP 'twice in succession, the decreasing inflection point X is not obtained.
It is determined that d has occurred. This is to eliminate variations in detection data due to disturbance and the like, and to accurately detect inflection points.

As described above, the decrease counter Cdec
Becomes 2 and it is determined that the decreasing-side inflection point Xd has occurred. Then, the above-described steps S9 to S13 are executed, and this time, the increment dP of the master cylinder pressure P obtained in the current control cycle is calculated. It is determined whether or not the value is larger than the increment dP ′ obtained in the previous control cycle. If not, in step S14, the increase counter Cinc
Is kept at 0.

On the other hand, when the present increment dP of the master cylinder pressure P has become larger than the previous increment dP ', as shown by the symbol "a" in FIG. Let the value be 1.
Also, in the next control cycle, if the increment dP obtained in that cycle is larger than the previous increment dP ', the increment counter Ci is again set in step S15.
The value is set to 2 by adding 1 to nc.

In this way, similarly to the case of the decrease counter Cdec, when the current increment dP becomes larger than the previous increment dP 'twice consecutively, the master cylinder pressure P
Is increased from the decreasing side to the increasing side, and it is determined that the increasing side inflection point Xi of the master cylinder pressure P has occurred. In this case, it is determined that the increasing inflection point Xi has occurred for the first time when the current increment dP becomes larger than the previous increment dP ′ twice consecutively, because the decreasing inflection point Xd
Is the same as

As described above, the decrease counter Cdec
And the value of the increase counter Cinc becomes 2, and as shown in FIG. 7, after the master cylinder pressure P rises immediately after the brake pedal 1 is depressed, the decreasing inflection point Xd
If the master cylinder pressure P starts to increase in earnest along with the start of the boosting operation of the booster 2 via the increase side inflection point Xi, then steps S16 and S17 are executed, and It is determined whether or not the master cylinder pressure P at the time is higher than a predetermined pressure P0, and whether or not its rising speed vP is higher than a predetermined speed V0. Is determined.

Then, P> P0 and vP> V0
, Ie, when it is determined that the vehicle is in an emergency, steps S18 and S19 are executed, and whether or not the vehicle speed S at that time is lower than the predetermined vehicle speed S0, and whether the steering angular speed ω of the steering wheel is the predetermined angular speed ω0 It is determined whether it is smaller than. Then, S <S0 and ω <
When ω0, that is, when the vehicle speed S is lower than the predetermined vehicle speed S0 and the steering angular speed ω of the steering wheel 61 is lower than the predetermined angular speed ω0, step S20 is executed, and the controller 40
The assisting device 66 is controlled to reduce the assisting force, and further, the warning buzzer 67 is turned on to inform the driver that the assisting force is controlled to be small.
Step S21 is executed to turn on the motor 27.

On the other hand, if the vehicle speed S is not lower than the predetermined vehicle speed S0 and the steering angular speed ω of the steering wheel 61 is not lower than the predetermined angular speed ω0, step S20 is executed.
Is executed, step S21 is executed to turn on the motor 27.

As described above, when the master cylinder pressure P is higher than the predetermined pressure P0 and the ascending speed vP is higher than the predetermined speed V0, that is, when it is determined that it is an emergency, the motor 27 starts operating and brakes. Although the assist is performed, even in an emergency, when the vehicle speed S is lower than the predetermined vehicle speed S0 and the steering angular speed ω of the steering wheel 61 is lower than the predetermined angular speed ω0, the assist force of the power steering device 60 is reduced. As a result, excessive steering of the driver at low vehicle speed is suppressed, and tire grip on the road surface,
As a result, steering and braking in an emergency can be ensured.

In step S19, when the steering angular velocity ω of the steering wheel 61 is not smaller than the predetermined angular velocity ω0, that is, when the steering angular velocity ω is equal to or higher than the predetermined angular velocity ω0, step 20 is not executed. If the steering angular velocity ω is still larger than the predetermined angular velocity ω0 and the steering operation is performed in a state where the assisting force of the device is reduced, the steering operation of the driver is assisted by returning to the control by the normal power steering device. The driver can easily and quickly perform large steering.

In step S19, it is determined whether or not the steering angular velocity ω of the steering wheel 61 is smaller than the predetermined angular velocity ω0. Instead, the steering angle A of the steering wheel 61 becomes larger than the predetermined angle A0. A determination element for determining whether the vehicle speed is small or not may be provided.
Is smaller than the predetermined vehicle speed S0, step S20 may be executed. When step S19 is used as a determination element for determining whether or not the steering angle A of the steering wheel 61 is smaller than the predetermined angle A0, when the steering angle A is not smaller than the predetermined angle A0, the steering angle speed ω of the steering wheel 61 is determined. Control by a normal power steering device is performed in the same manner as when making the determination.

As described above, when the motor 27 is turned on and the brake assist is started, thereafter, FIG.
Steps S7 to S22 of the flowchart of FIG. 3 are executed, and the master cylinder pressure P is lower than the predetermined pressure P0 of the above-described condition for starting the motor operation by a predetermined value p (P0−
p) It is determined whether or not it has fallen below. Then, when the master cylinder pressure P falls below the pressure (P0-p) due to a decrease in the depressing force of the brake pedal 1, etc., step S23 is executed to turn off the motor 27 and terminate the brake assist ( 7).

In this case, the master cylinder pressure P fluctuates around the predetermined pressure P0 by setting the pressure as the termination condition lower than the predetermined pressure P0 as the start condition by a predetermined value p. Control hunting is prevented.

The brake pedal 1 is returned and the brake switch 4 is turned on even during the operation start determination of the motor 27 and during the operation indicated by the steps after step S7.
2 is OFF, steps S5 and S6 determine that the decrement counter Cdec and the increment counter Cinc at that time.
Is cleared to prepare for the next brake operation, and the motor 27 is turned off to terminate the control of the brake assist.

[0059]

According to the first aspect of the present invention, when the brake assisting device is operated, the assisting force of the power steering device when the vehicle speed is low is smaller than the assisting force when the vehicle speed is high. When the brake assisting means is operated, the assisting force of the power steering device is smaller when the vehicle speed is low than when the vehicle speed is high. Steering can be suppressed, and the grip force of the tire on the road surface can be ensured. As a result, the brake assist device can operate effectively.

Next, according to the vehicle control device of the second invention, when the brake assisting device operates, if the vehicle speed is equal to or lower than the predetermined vehicle speed, the control device for reducing the assisting force of the power steering device is provided. During operation of the brake assisting means, when the vehicle speed is equal to or lower than a predetermined vehicle speed, the assisting force of the power steering device is reduced. As a result, excessive steering of the driver when the vehicle speed is equal to or lower than the predetermined vehicle speed is suppressed, and the tire road surface is suppressed. Grip force against
The brake assist device can operate effectively.

Further, according to the vehicle control apparatus of the third invention, the control means reduces the assisting force of the power steering apparatus when at least one of the steering angle or the steering angular velocity becomes a predetermined value or more. Therefore, if a large steering operation of a predetermined value or more is performed in a state where the assisting force of the power steering device is reduced, the control returns to the normal control of the power steering device and the driver's operation is stopped. The steering operation is assisted, and the steering can be made large and easy.

According to the vehicle control device of the fourth invention, the notifying means for notifying the driver that the assisting force of the power steering device has been reduced is provided, so that the assisting force of the power steering device is provided to the driver. Recognizing that the driver has become smaller, the driver's discomfort when the assisting force is small can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram of a braking device according to an embodiment of the present invention.

FIG. 2 is a schematic view of a booster used in the system.

FIG. 3 is a schematic diagram of a power steering device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the first embodiment.

FIG. 5 is an explanatory diagram of an operation of detecting a reduction side inflection point in the embodiment.

FIG. 6 is an explanatory diagram of an operation of detecting an inflection point on the increasing side.

FIG. 7 is a diagram showing a change in master cylinder pressure during a brake operation in an emergency or the like.

FIG. 8 is a diagram showing a change in master cylinder pressure at the time of a brake operation in an emergency and during sports running.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 brake pedal 2 booster (brake assisting means) 27 pump drive motor 40 controller (control means) 42 brake switch 44 master cylinder pressure sensor 60 power steering device 61 steering wheel 66 power steering assist device 67 warning buzzer

Claims (4)

[Claims] 1. A power steering device for assisting a steering force of a driver, a vehicle speed detecting means for detecting a vehicle speed, and a power steering assisting force adjusting means for adjusting the assisting force of the power steering device according to the vehicle speed. A brake assisting device for assisting a braking force generated by operation of a brake pedal, wherein the assisting force of the power steering device when the vehicle speed is low and the vehicle speed is high when the brake assisting device is activated. A control device for a vehicle, further comprising control means for reducing the assisting force of the vehicle. 2. A power steering device for assisting a driver's steering force, a vehicle speed detecting device for detecting a vehicle speed, a power steering assist force adjusting device for adjusting the assisting force of the power steering device according to the vehicle speed, A brake assisting device for assisting a braking force generated by operation of a brake pedal, wherein the assisting force of the power steering device is reduced when the vehicle speed is equal to or lower than a predetermined vehicle speed when the brake assisting device is operated. A control device for a vehicle, comprising a control unit. 3. The control device according to claim 1, wherein the control means stops the control for reducing the assisting force of the power steering device when at least one of the steering angle and the steering angular velocity becomes equal to or larger than a predetermined value. 3. The control device for a vehicle according to 1 or 2. 4. The control device for a vehicle according to claim 1, further comprising a notification unit that notifies a driver that the assisting force of the power steering device has been reduced.