JPH1120638A - Braking force controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking force controller provided with a pump which suctions brake fluid from a master cylinder and feeds it to a wheel cylinder under pressure so as to accurately detect a brake operation amount that a driver intends while brake assist control is performed. SOLUTION: This controller is provided with a liquid pressure sensor 29 which outputs a signal pMC corresponding to master cylinder pressure. It is provided with a pump 100 which suctions brake fluid from a master cylinder 18. When emergency brake operation is performed, discharge pressure of the pump 100 is supplied to a wheel cylinder. When brake fluid is suctioned into the pump 100, the reduction of master cylinder pressure in the interlocking relationship with the suction occurs due to its effect. The effect of the reduction of master cylinder pressure in the interlocking relationship with the suction is removed from pMC to generate a control signal pMC*. Brake assist control is performed based on the pMC*.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device, and more particularly to a braking force control device suitable for controlling a vehicle braking force.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 0, there is known a braking force control device that generates a larger brake fluid pressure than normal when a brake pedal is depressed at a speed exceeding a predetermined speed.
The driver of the vehicle operates the brake pedal at a high speed when it is desired to quickly increase the braking force. According to the above-described conventional braking force control device, when such a braking operation (hereinafter, referred to as an emergency braking operation) is performed, a larger braking fluid pressure is generated as compared with a normal operation, so that the driver's demand can be appropriately adjusted. Braking force can be generated.

[0003]

A control for generating a larger brake fluid pressure than usual when an emergency brake operation is performed (hereinafter, this control is referred to as brake assist control) is performed, for example, by a master cylinder. And the wheel cylinder are communicated via a first on-off valve, and the master cylinder and the suction side of the pump are communicated via a second on-off valve, and
It can be implemented in a system that communicates the discharge side of the pump with the wheel cylinder.

According to the above system, the first on-off valve is opened and the second on-off valve is closed, so that the master cylinder and the wheel cylinder are electrically connected and the master cylinder is closed. And the pump can be shut off. In this case, a wheel cylinder pressure P _{W / C} equal to the master cylinder pressure P _{M / C} can be generated in the wheel cylinder. Therefore, according to the above-described system, by realizing the above-described state, the system can be operated as a normal brake device.

According to the above system, the first on-off valve is closed, the second on-off valve is open, and
By operating the pump, the master cylinder and the wheel cylinder can be cut off, and the brake fluid in the master cylinder can be increased in pressure by the pump and supplied to the wheel cylinder. In this case, a high hydraulic pressure can be generated in the wheel cylinder as compared with the master cylinder pressure PM _{/ C.} Therefore, according to the above system,
By realizing the above-described state, the brake assist control can be executed.

In the above-mentioned system, for example, a master cylinder pressure P _{M / C} can be detected by disposing a hydraulic pressure sensor in a hydraulic passage communicating the master cylinder and the first on-off valve. is there. If the master cylinder pressure PM _{/ C} can be detected during the execution of the brake assist control, the detected value can be used to detect a brake operation performed by the driver after the start of the brake assist control.

However, in the above-mentioned system, that is, in a system in which brake fluid is sucked into the pump from the master cylinder, a hydraulic pressure passage for communicating the master cylinder and the first on-off valve after the suction of the brake fluid is started. , A pressure fluctuation not caused by the increase or decrease of the brake operation amount occurs. For this reason, in the above-mentioned system, simply detecting the master cylinder pressure P _{M / C} using the above-mentioned hydraulic pressure sensor can accurately determine the details of the brake operation performed by the driver during the execution of the brake assist control. It cannot be detected.

The present invention has been made in view of the above points, and uses a system configuration including a pump for sucking brake fluid from a hydraulic passage communicating between a master cylinder and a wheel cylinder, and has a brake assist control. It is an object of the present invention to provide a braking force control device capable of accurately detecting the amount of brake operation intended by a driver during the execution of (1).

[0009]

The above object is achieved by the present invention.
As described in the above, a hydraulic pressure sensor that generates an output signal corresponding to the master cylinder pressure, and a pump that sucks brake fluid from a hydraulic pressure passage that communicates the master cylinder and the wheel cylinder are provided. Is executed, a brake force control device that executes a brake assist control for supplying a hydraulic pressure discharged from the pump to a wheel cylinder, wherein the output is output when the pump sucks brake fluid from the hydraulic pressure passage. The present invention is achieved by a braking force control device including: a control signal generation unit that generates a control signal by correcting a decrease in a signal; and a hydraulic pressure control unit that performs the brake assist control using the control signal.

In the present invention, when the driver performs an emergency braking operation, the brake assist control is started. During the execution of the brake assist control, a large wheel cylinder pressure is generated by supplying the brake fluid discharged from the pump to the wheel cylinder.
After the brake assist control is started, the driver increases the brake operation force when requesting a larger braking force,
When a smaller braking force is required, the braking operation force is reduced. If these brake operations are performed during the execution of the brake assist control, a change corresponding to the brake operations appears in the master cylinder pressure, that is, in the output signal of the hydraulic pressure sensor. Therefore, the driver's intention can be detected based on the output signal of the hydraulic pressure sensor.

In the braking force control device according to the present invention, the brake fluid supplied to the wheel cylinder is controlled by the pump during the execution of the brake assist control.
It is sucked from a hydraulic passage that communicates the master cylinder and the wheel cylinder. When the brake fluid in the hydraulic passage is sucked into the pump, the master cylinder pressure temporarily decreases. The output signal of the hydraulic pressure sensor reflects the change in the master cylinder pressure due to the brake operation and the change in the master cylinder pressure due to the operation of the pump described above. The control signal is generated by eliminating the influence of the operation of the pump from the output signal of the hydraulic pressure sensor. Therefore, the control signal accurately reflects the change in the master cylinder pressure due to the driver's brake operation.

In the present invention, during execution of the brake assist control, the wheel cylinder pressure is controlled based on the control signal. For this reason, according to the present invention, it is possible to appropriately control the wheel cylinder pressure according to the driver's brake operation during the execution of the brake assist control. According to a second aspect of the present invention, in the braking force control device according to the first aspect, the control signal generating means outputs the output of the hydraulic pressure sensor after the pump starts sucking brake fluid. A local minimum value detecting unit that detects a local minimum value generated in the signal, a decrease detecting unit that detects a decrease generated in the output signal until the minimum value is reached, and after the minimum value is detected, A first generation unit that generates the control signal by correcting an output signal based on the decrease.

In the present invention, when the suction of the brake fluid by the pump is started, the output signal of the hydraulic pressure sensor decreases (hereinafter, this decrease is referred to as intake interlocking decrease). If the output signal that has been reduced due to the suction interlocking reduction has turned to an increasing tendency, that is, if the minimum value of the output signal is detected, it can be determined that the brake operation amount has been increased. In this case, the decrease in the output signal at the time when the minimum value is detected can be recognized as the decrease due to the inhalation-linked decrease. In the present invention, the control signal is generated based on the decrease. According to the above method, from the control signal,
It is possible to accurately remove the influence of a decrease in interlocking with suction.

[0014] The object of the present invention is as described in claim 3.
2. The braking force control device according to claim 1, wherein the control signal generating means includes a second generating means for holding the control signal at a constant value after the pump starts sucking brake fluid. Achieved by the device.

According to the present invention, when the brake operation amount is increased by the driver, the output signal tends to increase after the suction of brake fluid by the pump is started and then temporarily reduced due to the suction interlocking. Turn around. When the driver holds the brake operation amount, the output signal is maintained at a substantially constant value for a relatively long period after the output signal is reduced to some extent due to the suction interlocking reduction. When the driver has reduced the brake operation amount, the output signal continues to decrease after decreasing due to the decrease in intake interlocking. In this way, the output signal is
Immediately after the suction of the brake fluid by the pump is started, it tends to decrease. When the control signal is held at a constant value at the time when the suction interlock decreases in the output signal as in the present invention, it is possible to prevent the control signal from showing a decreasing tendency under the situation where the brake operation amount is increased or held. Can be.

[0016] The above object is as described in claim 4.
4. The braking force control device according to claim 3, wherein the control signal generation means includes a third generation means for making the control signal coincide with the output signal when an output signal of the hydraulic pressure sensor exceeds a predetermined value. Achieved by a power control.

In the present invention, if the output signal, which has been reduced due to the decrease in suction interlocking, returns to the level before the suction interlocking decrease again after the suction of brake fluid by the pump is started, the driver operates the brake operation. It can be recognized that the amount is increasing. In such a case, if the control signal is made to coincide with the output signal,
The tendency of the driver's brake operation amount can be accurately reflected.

[0018] The above object is as described in claim 5.
4. The braking force control device according to claim 3, wherein the control signal generation means adds the control signal to the output signal and the guard value when the output signal of the hydraulic pressure sensor falls below a guard value. This is achieved by a braking force control device including a fourth generation unit that sets the calculated value.

In the present invention, if the amount of decrease in the output signal exceeds the guard value after the pump starts inhaling brake fluid, it can be recognized that the driver has reduced the brake operation amount. In such a case, if the control signal is a value obtained by adding a guard value to the output signal, the control signal is reduced in the same tendency as the brake operation amount while eliminating the influence of the suction interlock reduction from the control signal. Can be done.

[0020] The above object is as described in claim 6.
6. The braking force control device according to claim 5, wherein the control signal generation means includes a first setting means for setting the guard value based on a time during which the brake fluid is continuously suctioned by the pump. Achieved by a power control.

In the present invention, the control signal is maintained at a constant value until the output signal falls below the guard value.
If the guard value is an unduly large value, the period during which the control signal is maintained at a constant value decreases for a long time even though the driver reduces the brake operation amount. On the other hand, if the guard value is an improperly small value, a situation occurs in which the output signal decreases to the guard value while the output signal is decreasing due to the inhalation interlocking decrease. Therefore, it is desirable that the guard value is a value that is slightly larger than the decrease generated in the output signal due to the decrease in the suction interlock.

The amount of decrease in the output signal caused by the decrease in the suction interlock varies depending on the time during which the pump continues to suck the brake fluid (hereinafter referred to as the suction continuation time). Specifically, the amount of decrease in the output signal increases as the suction duration increases, and decreases as the suction duration decreases. Therefore, it is desirable that the guard value for maintaining the control signal at a constant value be set based on the suction duration. In the present invention, the guard value is set based on the suction continuation time. Therefore, according to the present invention, it is possible to appropriately exclude the influence of the intake interlocking reduction from the control signal, and to appropriately reflect the driver's intention in the control signal.

[0023] The above object is as described in claim 7.
6. The braking force control device according to claim 5, wherein the hydraulic pressure control means implements a plurality of modes in which the time during which brake fluid is continuously sucked by the pump is different from each other, and the control signal generation means includes: This is achieved by a braking force control device including a second setting unit that sets the guard value based on a mode executed by the hydraulic pressure control unit.

In the present invention, it is desirable that the guard value is a value slightly larger than a decrease in the output signal accompanying the operation of the pump. The lowering of the output signal caused by the operation of the pump tends to be larger as the suction duration is longer. The inhalation duration is uniquely determined according to the mode to be executed. Thus, the amount of reduction in the output signal that accompanies the operation of the pump is primarily determined for the mode being executed. In the present invention, the guard value is set based on the mode to be executed. For this reason, according to the present invention, it is possible to appropriately exclude the influence of the operation of the pump from the control signal and appropriately reflect the driver's intention in the control signal.

[0025] The above object is as described in claim 8.
6. The braking force control device according to claim 5, wherein the control signal generating means is configured to start the hydraulic pressure based on an output signal output from the hydraulic pressure sensor when the pump starts sucking brake fluid. And a third setting means for setting the guard value based on the starting hydraulic pressure.

In the present invention, it is desirable that the guard value is a value slightly larger than a decrease in the output signal accompanying the operation of the pump. The decrease in the output signal caused by the operation of the pump increases as the master cylinder pressure increases at the time when the suction of the brake fluid by the pump starts, that is, as the starting hydraulic pressure increases. Value. In the present invention, the guard value is set based on the starting hydraulic pressure. For this reason, according to the present invention, it is possible to appropriately exclude the influence of the operation of the pump from the control signal and appropriately reflect the driver's intention in the control signal.

[0027] The above object is as described in claim 9,
The braking force control device according to claim 1, wherein the control signal generating unit is configured to stop the suction of the brake fluid by the pump, and until a predetermined time elapses,
This is achieved by a braking force control device including: a fifth generation unit that holds the control signal at a constant value; and a sixth generation unit that matches the control signal with the output signal after the predetermined time has elapsed. .

In the present invention, when the suction of the brake fluid by the pump is stopped, the master cylinder pressure becomes a hydraulic pressure according to the brake operation amount after pulsation occurs. Therefore, the output signal has a value that accurately reflects the brake operation amount after a predetermined period has elapsed after the suction of the brake fluid by the pump is stopped. In the present invention, the control signal is maintained at a constant value for a predetermined period after the suction of the brake fluid by the pump is stopped, and then has a value that matches the output signal. According to the above method, the brake operation amount can be accurately reflected in the control signal before and after the suction of the brake fluid by the pump is stopped.

According to a tenth aspect of the present invention, in the braking force control device according to the first aspect,
A valve means is provided between the master cylinder and the wheel cylinder, and the hydraulic pressure sensor and the suction side of the pump are achieved by a braking force control device communicating between the valve means and the master cylinder.

In the present invention, the master cylinder and the wheel cylinder are shut off by valve means. When the pump operates in such a situation, the hydraulic pressure between the valve means and the master cylinder tends to decrease due to the suction of brake fluid by the pump. Therefore, in that case, the output signal of the hydraulic pressure sensor decreases even if the brake operation amount is not reduced. In the present invention, under the above circumstances,
By correcting the output signal, a control signal that accurately reflects the driver's braking operation is generated.

[0031]

FIG. 1 shows a system configuration diagram of a braking force control device according to an embodiment of the present invention. The braking force control device of this embodiment is a device suitable as a braking force control device mounted on a front engine / front drive type vehicle (FF vehicle). The braking force control device according to the present embodiment is controlled by an electronic control unit 10 (hereinafter, referred to as ECU 10).

The braking force control device has a brake pedal 12. A brake switch 14 is provided near the brake pedal 12. Brake switch 14
Outputs an ON signal when the brake pedal 12 is depressed. The ECU 10 controls the brake switch 14
It is determined whether or not the brake pedal 12 is depressed based on the output signal.

The brake pedal 12 is connected to a vacuum booster 16. The vacuum booster 16
When the brake pedal 12 is depressed, an assist force Fa having a predetermined boosting ratio with respect to the brake depression force F is generated. A master cylinder 18 is fixed to the vacuum booster 16. A first hydraulic chamber 20 and a second hydraulic chamber 22 are formed inside the master cylinder 18. In the first hydraulic chamber 20 and the second hydraulic chamber 22, a master cylinder pressure PM _{/ C} is generated in accordance with the resultant force of the brake depression force F and the assist force Fa.

A reservoir tank 24 is provided above the master cylinder 18. The master cylinder 18 and the reservoir tank 24 are electrically connected only when the depression of the brake pedal 12 is released. A first hydraulic pressure passage 26 and a second hydraulic pressure passage 28 communicate with the first hydraulic pressure chamber 20 and the second hydraulic pressure chamber 22 of the master cylinder 18, respectively.

The first hydraulic passage 26 is provided with a hydraulic sensor 29. The hydraulic pressure sensor 29 is connected to the first hydraulic pressure passage 26.
, That is, an electric signal pMC corresponding to the master cylinder pressure PM _{/ C} generated by the master cylinder 18. The output signal pMC of the hydraulic pressure sensor 29 is supplied to the ECU 10. The ECU 10 detects the master cylinder pressure PM _{/ C} based on the output signal pMC.

In the first hydraulic passage 26, a first master cut solenoid 30 (hereinafter referred to as SMC- ₁ 30) and a first reservoir cut solenoid 32 (hereinafter SRC- ₁ 32) are provided.
Is called). On the other hand, a second master cut solenoid 34 (hereinafter, SMC- ₂₎
34) and a second reservoir cut solenoid 36
(Hereinafter referred to as SRC- ₂₃₆ ).

Inside the SMC- ₁ 30 and SMC- ₂ 34, constant pressure release valves 38 and 40 are provided. SMC _-1
A hydraulic pressure passage 4 provided corresponding to the right rear wheel RR
2, and a hydraulic passage 44 provided corresponding to the left front wheel FL. Similarly, a hydraulic passage 46 provided corresponding to the left rear wheel RL and a hydraulic passage 48 provided corresponding to the right front wheel FR communicate with the SMC _- 234.

The SMC- ₁₃₀ and the SMC _- 234 maintain the valve-open state in a normal state, and connect the first hydraulic passage 26 and the hydraulic passages 42 and 44 with a drive signal supplied from the ECU 10. Alternatively, it is a two-position solenoid valve that connects the second hydraulic passage 28 and the hydraulic passages 46 and 48 via the constant pressure release valves 38 and 40, respectively. The SRC _-1 32 and the SRC _-2 36 are two-position solenoid valves that maintain a closed state in a normal state and are opened when a drive signal is supplied from the ECU 10.

A check valve 50 is provided between the first hydraulic passage 26 and the hydraulic passages 42 and 44. The check valve 50 is
This is a one-way valve that allows only fluid flow from the first hydraulic pressure passage 26 to the hydraulic pressure passages 42 and 44. Similarly, a check valve 52 is provided between the second hydraulic passage 28 and the hydraulic passages 46 and 48. The check valve 52 is a one-way valve that allows only the flow of the fluid from the second hydraulic passage 28 to the hydraulic passages 46 and 48.

In the hydraulic passage 42 corresponding to the right rear wheel RR,
A right rear wheel holding solenoid 54 (hereinafter, referred to as SRRH 54) communicates therewith. Similarly, a left front wheel holding solenoid 56 (hereinafter referred to as SF) is provided in the hydraulic passage 44 corresponding to the left front wheel FL.
LH56) is a hydraulic passage 4 corresponding to the left rear wheel RL.
6 has a left rear wheel holding solenoid 58 (hereinafter, SRLH58).
), But also a hydraulic passage 48 corresponding to the right front wheel FR.
Is connected to a right front wheel holding solenoid 60 (hereinafter, referred to as SFRH60). Hereinafter, when these solenoids are collectively referred to, they are referred to as “holding solenoid S ** H”. The holding solenoid S ** H is a two-position solenoid valve that keeps the valve open in a normal state and is closed when a drive signal is supplied from the ECU 10.

A right rear wheel pressure reducing solenoid 62 (hereinafter, referred to as SRRR 62) communicates with the SRRH 54. Similarly, the SFLH 56 has a left front wheel pressure reducing solenoid 64 (hereinafter, referred to as SFLR 64), and the SRLH 58 has a left rear wheel pressure reducing solenoid 66 (hereinafter, referred to as SRLR 66).
Further, a right front wheel pressure reducing solenoid 68 (hereinafter, referred to as SFRR 68) communicates with the SFRH 60, respectively. Hereinafter, these solenoids are collectively referred to as “pressure reducing solenoid S ** R”. The pressure reducing solenoid S ** R is
The solenoid valve is a two-position solenoid valve that maintains a closed state in a normal state and is opened when a drive signal is supplied from the ECU 10.

Wheel cylinders 70, 72, 74 and 76 communicate with the holding solenoids S ** H of the respective wheels. The wheel cylinders 70, 72, 74, 76
Are connected with check valves 80, 82, 84, 86, respectively. The check valves 80, 82, 84, 86 are connected to the hydraulic passages 42, 4 from the wheel cylinders 70, 72, 74, 76 side.
This is a one-way valve that allows only fluid flow toward the 4, 46, 48 side.

The SRRR 62 and the SFLR 64 communicate with a pressure reducing passage 88. Similarly, the SRLR 66 and the SFRR 68 communicate with the pressure reducing passage 90. Auxiliary reservoirs 92 and 94 communicate with the pressure reducing passages 88 and 90. The suction holes of the pumps 100 and 102 communicate with the auxiliary reservoirs 92 and 94 via check valves 96 and 98.
The suction holes of the pumps 100 and 102 are also provided with SRC- _13.
2 or SRC- ₂₃₆ is in communication.

When a drive signal is supplied from the ECU 10, the pumps 100 and 102 serve as auxiliary reservoirs 92 and 94.
Brake fluid stored in or SRC
Brake fluid guided through _-1 32 or SRC- ₂ 36 is discharged from the discharge hole. Pump 100,1
The discharge hole 02 communicates with the dampers 104 and 106. The dampers 104 and 106 absorb pulsations generated in the discharge pressures of the pumps 100 and 102. Dampers 104 and 106
Communicate with the hydraulic passages 44 and 46, respectively.

The braking force control device of the present embodiment includes wheel speed sensors 108, 110, 112, 114. Each of the wheel speed sensors 108, 110, 112, and 114 outputs a pulse signal at a cycle corresponding to the rotation speed of each wheel. The output signals of the wheel speed sensors 108, 110, 112, 114 are E
It is supplied to CU10. ECU10 detects the rotational speed V _W of each wheel based on the output signal of the wheel speed the wheel speed sensors 108, 110, 112, 114.

Next, the operation of the braking force control device of this embodiment will be described. The braking force control device according to the present embodiment switches the state of various solenoid valves disposed in the hydraulic circuit to provide a function as a normal brake device (hereinafter, referred to as a normal brake function) and an anti-lock brake. Function as a system (hereinafter referred to as ABS function), and
When a rapid rise of the braking force is required, a function of generating a larger braking force than usual (hereinafter, referred to as a brake assist function) is realized.

FIG. 1 shows a control for realizing a normal brake function (hereinafter, referred to as a normal brake control) or A
The state realized during execution of control for realizing the BS function (hereinafter, referred to as ABS control) is shown. Hereinafter, the state shown in FIG. 1 is referred to as a normal brake state. During the execution of the normal brake control, as shown in FIG. 1, all the solenoid valves provided in the braking force control device are turned off.
According to the normal brake state, the wheel cylinders 70, 72, 74, 76 of all the wheels communicate with the master cylinder 18. In this case, the wheel cylinder pressure P _{W / C} of each wheel is
The pressure is always controlled to be equal to the master cylinder pressure PM _{/ C.} Therefore, according to the normal brake state shown in FIG. 1, the normal brake function can be realized.

During execution of the ABS control, as shown in FIG. 1, SMC- ₁ 30, SRC- ₂ 32, SMC- ₁ 34 and SR
The C- ₂₃₆ is turned off and the pumps 100 and 1 are turned off.
02 is activated and the holding solenoid S ** H
And the pressure reducing solenoid S ** R is appropriately driven according to the request of the ABS. Hereinafter, a state realized during the execution of the ABS control is referred to as an ABS state.

According to the ABS state, the master cylinder pressure P _{M / C} can be guided to all four hydraulic passages 42, 44, 46, 48 provided corresponding to the respective wheels. In this state, when the holding solenoid S ** H is opened and the pressure reducing solenoid S ** R is closed, the wheel cylinder pressure P _{W / C} of each wheel is directed toward the master cylinder pressure P _{M / C.} Pressure can be increased. Hereinafter, this state is referred to as (i) pressure increase mode. In the above state, the holding solenoid S *
When both * H and the pressure reducing solenoid S ** R are closed, the wheel cylinder pressure P _{W / C} of each wheel can be maintained. Hereinafter, this state is referred to as (ii) holding mode.
Further, in the above state, when the holding solenoid S ** H is closed and the pressure reducing solenoid S ** R is opened, the wheel cylinder pressure P _{W / C} of each wheel can be reduced. . Hereinafter, this state is referred to as (iii) decompression mode.

When the ABS control is started, the ECU 10
Implements (i) the pressure increasing mode, (ii) the holding mode, and (iii) the pressure reducing mode as appropriate for each wheel so that an excessive slip rate does not occur in each wheel. When the holding solenoid S ** H and the pressure reducing solenoid S ** R are controlled as described above, the wheel cylinder pressures P _{W / C of} all wheels are controlled.
Is controlled to an appropriate pressure without causing an excessive slip rate on the corresponding wheel. As described above, according to the above control, the ABS function can be realized in the braking force control device.

FIGS. 2 to 4 show control (hereinafter referred to as BA) for realizing a brake assist function (hereinafter referred to as a BA function).
(Referred to as control). ECU
The control unit 10 starts the BA control so as to generate a larger braking force than usual when an emergency braking operation is performed by the driver. During the execution of the BA control, the ECU 10
Thus, any of the states shown in FIGS. 2 to 4 is appropriately realized.

FIG. 2 shows an assist pressure increasing state realized during execution of the BA control. The assist pressure increase state is BA
This is realized when it is necessary to increase the wheel cylinder pressure P _{W / C} of each wheel during execution of the control. In the system of this embodiment, the assist pressure increasing state is as shown in FIG.
SMC- ₁ 30, SRC- ₁ 32, SMC- ₂ 34 and SR
_Turn on C- ₂₃₆ (SMC- ₁₃₀ and SMC _- 234)
Is closed, SRC- ₁ 32 and SRC- ₂₃₆ are open, and the pumps 100 and 102 are turned on.

According to the assist pressure increasing state, the master cylinder 18 and the suction holes of the pumps 100 and 102 communicate with each other. In this case, the pumps 100 and 102 can suck the brake fluid from the master cylinder 18 and discharge the high-pressure brake fluid to the hydraulic passages 42 and 44 or the hydraulic passages 46 and 48. According to the assist pressure increasing state, the hydraulic passages 42, 44 and the hydraulic passages 46, 4
8 is separated from the master cylinder 18 by constant pressure release valves 38 and 40 built in the SMC- ₁ 30 or SMC- ₂ 34, respectively. In this case, the pumps 100, 10
2 is supplied to the hydraulic passage 4
The wheels are supplied to wheel cylinders 70, 72, 74, 76 via the wheels 2, 44, 46, 48.

Therefore, according to the assist pressure increasing state shown in FIG. 1, the brake fluid in the master cylinder 18 is pumped by the pumps 100 and 102 so that the wheel cylinder pressure P _{W / C} of each wheel is reduced by the master cylinder. The pressure can be increased to a higher hydraulic pressure than the pressure PM _{/ C.} FIG. 3 shows an assist pressure holding state realized during execution of the BA control. The assist pressure increasing state is realized when it is necessary to maintain the wheel cylinder pressure P _{W / C} of each wheel during execution of the BA control. In the system of this embodiment, the assist pressure holding state is, as shown in FIG. 3, the SMC- ₁₃₀ and the SMC- _2.
34 is turned on (valve closed state) and the pump 10
This is realized by turning on 0 and 102.

According to the assist pressure holding state, SRC- ₁₃
2 and SRC _- 236 allow the suction holes of pumps 100 and 102 and master cylinder 18 to be shut off. In this case, the pumps 100 and 102 cannot suck the brake fluid from the master cylinder 18. In addition, ABSs are provided inside the auxiliary reservoirs 92 and 94.
Before the control is started, the brake fluid is not stored. Therefore, when the assist pressure holding state is realized, the pumping of the brake fluid by the pumps 100 and 102 is stopped. Therefore, according to the assist pressure holding state, the wheel cylinder pressures P _{W / C} of all the wheels can be held at a constant value.

FIG. 4 shows a reduced assist pressure state realized during execution of the BA control. The assist pressure reduction state is BA
This is realized when it is necessary to reduce the wheel cylinder pressure P _{W / C} of each wheel during execution of the control. In this embodiment,
The assist pressure reduction state is realized by turning off all the solenoids as shown in FIG. According to the reduced assist pressure state, SRC- ₁ 32 and SRC- ₂ 36 are closed. In this case, the pumps 100 and 102 cannot pump the brake fluid. Further, according to the assist pressure reduction state, the wheel cylinders 7
0, 72, 74, and 76 are SMC- ₁ 30 or SMC3
4 and communicate with the master cylinder 18. For this reason,
According to the assist pressure reduction state, the wheel cylinder pressure P _{W / C} of all wheels can be reduced with the master cylinder pressure P _{M / C} as a lower limit.

FIG. 5 shows changes that occur in the master cylinder pressure P _{M / C} and the wheel cylinder pressure P _{W / C} when the driver performs an emergency brake operation. When the driver performs an emergency braking operation, the master cylinder pressure P _{M / C} sharply increases as shown by a broken line in FIG. 5. Based on the output signal pMC of the hydraulic pressure sensor 29, the ECU 10 increases the master cylinder pressure PM _{/ C} rapidly and
If it can be recognized that the pressure has been increased to a sufficiently large value, it is determined that the emergency braking operation has been performed. And ECU1
If 0 determines that the emergency braking operation has been performed, then the BA control is started.

When the BA control is started in the braking force control device, first, (I) a start pressure increasing mode is executed (period in FIG. 5). The start pressure increase mode uses a predetermined duty ratio Duty
1 is realized by repeating the assist pressure increasing state shown in FIG. 2 and the assist pressure holding state shown in FIG. More specifically, SMC- ₁₃₀ and SMC- ₂₃
4 is maintained in the ON state (valve closed state), and the pumps 100, 1
02 in operation and SRC _-1 32 and S
This is realized by repeatedly turning on / off the RC _- 236 at a predetermined duty ratio Duty1.

The start pressure increase mode is a predetermined pressure increase time T _STA
It is continuously executed during The pressure increase time T _STA is set to a time necessary for increasing the wheel cylinder pressure P _{W / C} by a predetermined assist pressure Pa compared to the master cylinder pressure P _{M / C.} The predetermined assist pressure Pa is a pressure required to generate a predetermined deceleration G ₀ to the vehicle. Therefore, when the start pressure increase mode is executed, the vehicle generates a deceleration G + G _{0 which} is larger by the predetermined value G ₀ than the deceleration G generated by the normal brake control.

In the braking force control device, when (I) the start pressure increasing mode is completed, (II) the assist pressure increasing mode, (III) the assist pressure decreasing mode, One of the IV) assist pressure holding mode, the (V) assist pressure gradual increase mode, and the (VI) assist pressure gradual decrease mode are executed. FIG. 6 shows an example of a map referred to by the ECU 10 in order to determine a mode to be executed after the start pressure increase mode. In FIG. 6, the horizontal axis represents the hydraulic pressure sensor 2.
9 is the change rate dpMC / dt of the output signal pMC.

If a positive rate of change occurs in the master cylinder pressure PM _{/ C} at the end of the start pressure increase mode, it can be determined that the driver is requesting a larger braking force. When a change rate dpMC / dt exceeding a predetermined value K ₁ (> 0) occurs at the end of the start pressure increase mode, the ECU 10 determines that the driver is requesting a larger braking force. In this case, the ECU 10 determines the mode to be executed after the start pressure increasing mode to be (II) the assist pressure increasing mode.

If a negative rate of change occurs in the master cylinder pressure PM _{/ C} at the end of the start pressure increase mode, it can be determined that the driver has requested a decrease in the braking force. The ECU 10 determines that the driver is requesting a decrease in the braking force when the rate of change dpMC / dt is smaller than the predetermined value K ₂ (<0) at the time when the start pressure increase mode ends. In this case, the ECU 10 determines the mode to be executed after the start pressure increasing mode to be (III) the assist pressure decreasing mode.

If the master cylinder pressure P _{M / C} does not show a large change rate at the end of the start pressure increase mode, it can be determined that the driver has requested the holding of the braking force. . The ECU 10 determines the rate of change dp that satisfies K ₂ ≦ dpMC / dt ≦ K ₁ at the end of the start pressure increase mode.
When MC / dt has occurred, it is determined that the driver has requested the holding of the braking force. In this case, the ECU 10 determines the mode to be executed after the start pressure increasing mode to be (IV) the assist pressure holding mode.

(II) The assist pressure increase mode is used when the brake operation amount is greatly increased at the end of the above-described start pressure increase mode, or when the assist pressure holding mode described later is being executed or the assist pressure is gradually increased. This is executed when the brake operation amount is greatly increased during execution of the mode (FIG. 5).
Medium period). The assist pressure increasing mode is realized by repeating the assist pressure increasing state shown in FIG. 2 and the assist pressure holding state shown in FIG. 3 at a predetermined duty ratio Duty2. Note that the duty ratio Duty2 used in the assist pressure increase mode may be the same as or different from the duty ratio Duty1 used in the start pressure increase mode. According to the assist pressure increasing mode, when the brake operation amount is greatly increased, the wheel cylinder pressure P _{W / C} of each wheel is rapidly increased in a region higher than the master cylinder pressure P _{M / C.} Can be pressed.

FIG. 7 shows an example of a map referred to by the ECU 10 to determine a mode to be executed during the execution of the assist pressure increasing mode. In FIG. 7, the horizontal axis represents the change rate dpMC / dt of the output signal pMC of the hydraulic pressure sensor 29. If the increase of the master cylinder pressure PM _{/ C} continues during the execution of the assist pressure increasing mode, it can be determined that the driver is requesting a larger braking force. E
The CU 10 sets the predetermined value K during execution of the assist pressure increasing mode.
_If a change rate dpMC / dt exceeding ₃ (> 0) occurs, it is determined that the driver requests a larger braking force. In this case, the ECU 10 determines the mode to be executed,
The mode is continuously set to the assist pressure increasing mode.

Further, during execution of the assist pressure increasing mode,
If a large increase has not occurred in master cylinder pressure PM _{/ C} , it can be determined that the driver no longer requests an increase in the braking force. During execution of the assist pressure increasing mode, the ECU 10 determines that the rate of change d exceeds a predetermined value K ₃ (> 0).
If pMC / dt has not occurred, it is determined that the driver has not requested an increase in the braking force. In this case, the ECU 10
Determines the mode to be executed to be the assist pressure holding mode.

(III) The assist pressure reduction mode is used when the brake operation amount is greatly reduced at the end of the above-described start pressure increase mode, or during the execution of the assist pressure holding mode described later or the assist pressure gradual reduction mode. Is executed when the brake operation amount is greatly reduced during the execution of the operation (the period in FIG. 5). In the assist pressure reducing mode, the assist pressure holding state shown in FIG.
This is realized by repeating the assist pressure reduction state shown in FIG. More specifically, SRC _-1 32 and SRC _-2 36 are maintained in the off state (valve closed state), pumps 100 and 102 are maintained in the operating state, and SMC _-13
This is realized by repeatedly turning on and off 0 and SMC _- 234 at a predetermined duty ratio Duty3. According to the assist pressure reduction mode, when the brake operation amount is greatly reduced, the wheel cylinder pressure P _{W / C} of each wheel is
With the master cylinder pressure P _{M / C} as the lower limit, the pressure can be rapidly reduced.

FIG. 8 shows an example of a map referred to by the ECU 10 to determine the mode to be executed during the execution of the assist pressure reducing mode. In FIG. 8, the horizontal axis represents the change rate dpMC / dt of the output signal pMC of the hydraulic pressure sensor 29. If the master cylinder pressure PM _{/ C} continues to decrease during the execution of the assist pressure reducing mode, it can be determined that the driver is requesting a smaller braking force. E
The CU 10 sets the predetermined value K during execution of the assist pressure increasing mode.
_{If a} change rate dpMC / dt lower than ₄ (<0) occurs, it is determined that the driver is requesting a smaller braking force. In this case, the ECU 10 determines the mode to be executed,
The mode is continuously set to the assist pressure reduction mode.

Further, during execution of the assist pressure reducing mode,
If the master cylinder pressure P _{M / C} has not significantly decreased, it can be determined that the driver no longer requests a decrease in the braking force. During execution of the assist pressure reduction mode, the ECU 10 sets the rate of change d below a predetermined value K ₄ (<0) d.
If pMC / dt has not occurred, it is determined that the driver has not requested a decrease in the braking force. In this case, the ECU 10
Determines the mode to be executed to be the assist pressure holding mode.

(IV) In the assist pressure holding mode, a large increase or decrease in the brake operation amount occurs at the end of the above-described start pressure increasing mode or during execution of the assist pressure increasing mode or the assist pressure decreasing mode described above. It is executed when it is detected that there is not, and after the assist pressure gradual increase mode or the assist pressure gradual decrease mode described later is executed for a predetermined period (period in FIG. 5).

The assist pressure holding mode is realized by maintaining the assist pressure holding state shown in FIG.
According to the assist pressure holding mode, the wheel cylinder pressure P _{W / C} of each wheel can be maintained at a constant value when the brake operation amount does not greatly change. FIG. 9 shows an example of a map that the ECU 10 refers to to determine a mode to be executed during the execution of the assist pressure holding mode.
In FIG. 9, the horizontal axis represents the output signal p of the hydraulic pressure sensor 29.
The change rate of MC is dpMC / dt. The vertical axis represents the output value pMCS at the time of change from the output signal pMC of the hydraulic pressure sensor 29.
This is a value obtained by subtracting TA. The output value pMCSTA at the time of change is
When the assist pressure holding mode is started, the hydraulic pressure sensor 2
9 is the value of the output signal pMC that has been output from FIG. Therefore, in FIG. 9, the vertical axis corresponds to the amount of change in the output signal pMC in the increasing direction after the start of the assist pressure holding mode.

If the master cylinder pressure P _{M / C} sharply increases during the execution of the assist pressure holding mode, it can be determined that the driver has requested a sharp increase in the braking force. E
CU10, after the assist pressure holding mode is started, before the predetermined time T _MODE1 elapses, change exceeding a predetermined value P ₁ in the output signal pMC (i.e., pMC-pMCSTA
> P ₁ changes to meet) is generated, and the increase in the driver abruptly braking force when the change rate dpMC / dt at the time the change occurs exceeds a predetermined value K ₅ (> 0) Judge that it is requesting. In this case, the ECU 10 changes the mode to be executed from the assist pressure holding mode to the assist pressure increasing mode.

If the master cylinder pressure P _{M / C} drops sharply during execution of the assist pressure holding mode, it can be determined that the driver has requested a sharp decrease in the braking force. E
CU10, after the assist pressure holding mode is started, before the predetermined time T _MODE1 elapses, decreases the output signal pMC exceeds a predetermined value P ₄ (i.e., pMC-pMCSTA
<Drops) until P ₄ is satisfied, and, a decrease of the driver is sudden braking amount when the rate of change dpMC / dt at the time the drop has occurred is less than the predetermined value K ₆ (<0) Judge that it is requesting. In this case, the ECU 10 changes the mode to be executed from the assist pressure holding mode to the assist pressure reducing mode.

If the master cylinder pressure P _{M / C} gradually increases during execution of the assist pressure holding mode, it can be determined that the driver has requested a gradual increase in the braking force. After the assist pressure holding mode is started, the ECU 10 does not satisfy the above-described condition for shifting to the assist pressure increasing mode or the assist pressure decreasing mode, and outputs a predetermined time T _MODE1 to the output signal pMC continuously. Value P ₂ (0 <
Changes exceeding P ₂ <P ₁ (i.e., pMC-pMC)
If the change meets the STA> P ₂₎ has occurred, it is determined that the driver is requesting a moderate increase in the braking force. In this case, the ECU 10 changes the mode to be executed from the assist pressure holding mode to the assist pressure gradual increase mode.

If the master cylinder pressure P _{M / C} is gradually decreasing during execution of the assist pressure holding mode, it can be determined that the driver has requested a gentle decrease in the braking force. After the assist pressure holding mode is started, the ECU 10 does not satisfy the above-described condition for shifting to the assist pressure increasing mode or the assist pressure decreasing mode, and outputs a predetermined time T _MODE1 to the output signal pMC continuously. Value P ₃ (0>
P _3> P ₄₎ decreases below (i.e., pMC-pMC
If the STA <lowering satisfying P ₃₎ has occurred, it is determined that the driver is requesting a moderate reduction of the braking force. In this case, the ECU 10 changes the mode to be executed from the assist pressure holding mode to the assist pressure gradual decrease mode.

Further, during execution of the assist pressure holding mode,
Master cylinder pressure P_{M / C}When there is no significant change in
Can determine that the driver has requested the braking force to be maintained.
You. The ECU 10 has started the assist pressure holding mode.
After that, the change amount of the output signal pMC becomes a predetermined value P_TwoAnd P_ThreeBetween
(Ie, P_Three≤pMC-pMCSTA≤
P _TwoIs satisfied), the driver requests the holding of the braking force.
Judge that you are. In this case, the ECU 10
The torsion pressure holding mode is maintained as a mode to be executed.

(V) The assist pressure gradual increase mode is executed when a gradual increase in the brake operation amount is detected during execution of the assist pressure holding mode, as described above. When the execution of the assist pressure gradual increase mode is requested, the ECU 10 maintains the braking force control device in the assist pressure increase state shown in FIG. 2 for a predetermined short time T _MODE2 . And the ECU 10
As long as a sudden increase in the brake operation amount is not detected, after a predetermined time T _MODE2 has elapsed, the assist pressure gradual increase mode is ended and the assist pressure holding mode is started again. According to the assist pressure gradual increase mode, the wheel cylinder pressure P _{W / C} of each wheel can be increased intermittently when the brake operation amount is gently increased.

FIG. 10 shows an example of a map referred to by the ECU 10 during execution of the assist pressure gradual increase mode to determine the mode to be executed. In FIG. 10, the horizontal axis represents the rate of change dpMC / dt of the output signal pMC of the hydraulic pressure sensor 29. The vertical axis represents the change amount pMC-pMCS generated in the output signal pMC after the assist pressure gradual increase mode is started.
TA.

If the master cylinder pressure PM _{/ C} sharply increases during execution of the assist pressure gradual increase mode, it can be determined that the driver has requested a rapid increase in the braking force. E
CU10, after the assist pressure moderately increasing mode is started, before the predetermined time T _MODE2 has elapsed, change exceeding a predetermined value P ₅ to the output signal pMC (i.e., pMC-pMCSTA
> P ₅ changes satisfying) is generated, and the increase in the driver abruptly braking force when the change rate dpMC / dt at the time the change occurs exceeds a predetermined value K ₇ (> 0) Judge that it is requesting. In this case, the ECU 10 changes the mode to be executed from the assist pressure gradual increase mode to the assist pressure increase mode.

If the master cylinder pressure P _{M / C} does not suddenly increase during execution of the assist pressure gradual increase mode,
It can be determined that the driver has not requested a rapid increase in the braking force. If the above-described condition for shifting to the assist pressure increasing mode is not satisfied before the predetermined time T _MODE2 has elapsed after the assist pressure gradual increasing mode has been started, the ECU 10 determines that the driver has a sudden braking amount. Is determined not to require an increase. In this case, the ECU 10 changes the mode to be executed from the assist pressure gradual increase mode to the assist pressure holding mode.

(VI) The assist pressure moderation mode is as described above.
Of the brake operation amount during execution of the assist pressure holding mode.
Executed when a gradual decrease is detected (Fig.
while). When execution of the assist pressure moderation mode is requested,
The ECU 10 determines a predetermined short time T _MODE3Only braking force control
Is maintained in the assist pressure reduced state shown in FIG. So
Then, the ECU 10 detects a sharp decrease in the brake operation amount.
Unless known, T_MODE3After elapse,
Terminate the cyst pressure moderate mode and restart the assist pressure holding mode.
Start loading. According to the assist pressure moderation mode,
When the operation amount is gradually reduced,
Wheel cylinder pressure P_{W / C}Can be depressurized intermittently.
Wear.

FIG. 11 shows an example of a map referred to by the ECU 10 to determine the mode to be executed during the execution of the assist pressure gradual decrease mode. In FIG. 11, the horizontal axis represents the rate of change dpMC / dt of the output signal pMC of the hydraulic pressure sensor 29. The vertical axis indicates the amount of change pMC−pMCS that has occurred in the output signal pMC after the start of the assist pressure moderate mode.
TA.

If the master cylinder pressure P _{M / C} drops rapidly during execution of the assist pressure gradual decrease mode, it can be determined that the driver has requested a sudden drop in the braking force. E
CU10, after the assist pressure moderately decreasing mode is started, before the predetermined time T _MODE3 elapses, decreases exceeding a predetermined value P ₆ to the output signal pMC (i.e., pMC-pMCSTA
<Drop) occurs satisfying P _6, and the driver when the rate of change dpMC / dt at the time the drop has occurred is less than the predetermined value K ₈ (<0) is requested to decrease the abrupt braking force Judge that you are. In this case, the ECU 10 changes the mode to be executed from the assist pressure gradual increase mode to the assist pressure decrease mode.

If the master cylinder pressure P _{M / C} does not suddenly decrease during the execution of the assist pressure moderate mode,
It can be determined that the driver has not requested a rapid decrease in the braking force. If the above-mentioned condition for shifting to the assist pressure reducing mode is not satisfied before the predetermined time T _MODE3 has elapsed after the assist pressure gradual decrease mode is started, the ECU 10 determines that the driver has a sudden braking amount. Judge that no reduction is requested. In this case, the ECU 10 changes the mode to be executed from the assist pressure gradual decrease mode to the assist pressure holding mode.

As described above, according to the braking force control apparatus of the present embodiment, when the driver performs an emergency braking operation, the BA control is executed to thereby control the wheel cylinder pressure P _{W / C of} each wheel. Can be increased to a pressure higher than the master cylinder pressure PM _{/ C.} Further, according to the braking force control device of the present embodiment, during the execution of the BA control, an increase or decrease in the driver's brake operation amount is detected based on the output signal pMC of the hydraulic pressure sensor 29, and the brake operation amount is detected. , The wheel cylinder pressure P _{W / C} can be increased or decreased. Therefore, according to the braking force control device of the present embodiment,
During the execution of the BA control, the braking force can be increased or decreased according to the driver's intention.

FIG. 12 is a time chart for explaining a change occurring in the output signal pMC of the hydraulic pressure sensor 29 during the execution of the BA control. Specifically, FIG. 12A shows the output signal pMC with the execution of (I) the starting pressure increasing mode, (II) the assist pressure increasing mode, or (V) the assist pressure gradual increasing mode. Indicates the changes that occur. FIG.
(B) and FIG. 12 (C) show SRC- ₁ 32 and SRC during execution of (I) start pressure increasing mode, (II) assist pressure increasing mode, or (V) assist pressure gradual increasing mode described above.
The driving state of the RC- ₂ 36 and the motors 100 and 102
3 shows the driving state.

As described above, (I) the starting pressure increase mode and (I)
I) During the execution of the assist pressure increasing mode, the assist pressure increasing state shown in FIG. 2 and the assist pressure holding state shown in FIG. 3 are repeated at predetermined duty ratios Duty1 and Duty2. Also, as described above, (V) the assist pressure gradual increase mode
This is realized by changing the braking force control device from the assist pressure holding state to the assist pressure increasing state for a predetermined period T _MODE2 . Therefore, during the execution of these modes, as shown in FIG. 12B and FIG.
0, 102 are kept in the driving state, and SRC _-1 32
And SRC- ₂₃₆ is opened in a pulsed manner.

In the braking force control device of the present embodiment, the pumps 100 and 102 are provided with SRC- ₁ 32 and SRC _- 236.
Is in the open state, the first hydraulic passage 26 or the second hydraulic
The brake fluid is sucked from the hydraulic passage 28 and supplied to the wheel cylinders 70, 72, 74, 76 of each wheel.
The internal pressure of the first hydraulic passage 26 and the second hydraulic passage 28, that is, the master cylinder pressure P _{M / C} , causes the pumps 100 and 102 to start inhaling brake fluid even when the amount of brake operation by the driver is constant. It is lowered by being done.

For this reason, the output signal pM of the hydraulic pressure sensor 29
C represents SRC _-1 32 and S as shown in FIG.
After the RC _- 236 changes from the closed state to the open state, the value temporarily becomes small regardless of the driver's intention. Less than,
As described above, after the suction of the brake fluid by the pumps 100 and 102 is started, the output signal pMC
Is referred to as a suction-linked decrease.

Brake full by pumps 100 and 102
After inhalation of the code is started, the SRC _-132 and SRC
_-2When the valve 36 is closed, the first hydraulic passage 26 and the
Fluctuation from the two hydraulic passages 28 to the pumps 100 and 102
The fluid flow is shut off. Pumps 100, 10
When the flow of brake fluid to
The internal pressure of the first hydraulic passage 26 and the second hydraulic passage 28,
And master cylinder pressure P_{M / C}Causes pulsation. others
Therefore, the output signal pMC of the hydraulic pressure sensor 29 is as shown in FIG.
As shown in SRC_-132 and SRC_-236 is open
For a certain period after changing from the state to the closed state, the driver
Pulsating regardless of the intention of

As described above, in the braking force control device of the present embodiment, when the state of SRC- ₁ 32 and SRC _- 236 changes, the output signal pMC of the hydraulic pressure sensor 29 changes the brake operation amount. May change independently of
Therefore, when the increase or decrease of the brake operation amount is determined based on the output signal pMC, a situation may occur in which the increase or decrease is determined even though the brake operation has not been increased or decreased.

In order to prevent the above-mentioned erroneous determination, the braking force control device of the present embodiment uses the output signal pMC to determine whether the pumps 100, 1
It is characterized in that a control signal pMC ^* that excludes the fluctuations associated with the operation of 02 is generated and BA control is executed based on the control signal pMC ^* . Hereinafter, a characteristic portion of the braking force control device according to the present embodiment will be described with reference to FIGS.

FIG. 13 shows an example of an ECU for realizing the above functions.
2 shows a flowchart of an example of a control routine executed by the control routine 10; The routine shown in FIG. 13 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 13 is started, first, the process of step 120 is executed. In step 120, it is determined whether or not the assist pressure increasing state (the state shown in FIG. 2) has been realized.
As a result, when it is determined that the assist pressure increasing state has been realized, the process of step 122 is executed next.

In step 122, it is determined whether or not this processing cycle is the first cycle after the assist pressure increasing state is realized. As a result, if it is determined that this is the first cycle after the state has changed, the process of step 124 is executed next. On the other hand, if it is determined that the current cycle is not the first cycle after the state change, step 124 is jumped, and the process of step 126 is executed.

In step 124, the output signal pMC output from the hydraulic pressure sensor 29 at that time is stored as the starting output value pMCON. In step 126, a correction term ΔpMC is calculated. In this step 126, specifically, “0”, “pMCON-pMC” and “α” are compared, and the intermediate value between them is calculated as the correction term ΔpMC
Is performed. Note that “α” used in step 126 is a guard value of the correction term ΔpMC.

In step 128, the maximum correction term ΔpMC
_MAX is calculated. In step 128, specifically, the correction term ΔpMC calculated in the current processing cycle and the maximum correction term ΔpMC calculated in the previous processing cycle
Comparing the _MAX, this computed correction term DerutapMC only if larger than the maximum correction term DerutapMC _MAX up to the previous time, the maximum correction term DerutapMC _MAX, updates to the current computed correction term DerutapMC process Be executed.

At step 130, the control signal pMC ^* is calculated. In this step 130, the control signal pM
C ^* is calculated by adding the maximum correction term ΔpMC _MAX to the output signal pMC. When the process of step 130 ends, the current routine ends. FIG.
FIG. 7 shows a diagram in which the output signal pMC of the hydraulic pressure sensor 29 is compared with the control signal pMC ^* calculated by the above processing. The dashed-dotted line and the solid line indicated by ^* in FIG. 14 respectively appear in the output signal pMC when the assist pressure increasing state is executed in a situation where the brake operation amount is increased. 5 shows a change and a change of the control signal pMC ^* corresponding to the output signal pMC.

Further, the dashed-dotted line and the solid line indicated by ^* in FIG. 14 are output when the assist pressure increasing state is executed under the condition that the brake operation amount is held. The change appearing in the signal pMC and the change in the control signal pMC ^* corresponding to the output signal pMC are shown. Similarly, the alternate long and short dash line shown in FIG.
^The solid lines indicated by * correspond to the change that appears in the output signal pMC when the assist pressure increasing state is executed in a situation where the brake operation amount is reduced, and the output signal pMC, respectively. The change of the control signal pMC ^* to be performed is shown.

In step 130, the control signal p
MC ^* is calculated according to a calculation formula of pMC ^* = pMC + ΔpMC _MAX . Further, according to the processing of step 128, the maximum correction term ΔpMC _MAX is updated to the newly calculated correction term ΔpMC every time the processing cycle is repeated, when the correction term ΔpMC continues to increase. The maximum correction term ΔpMC _MAX is maintained at the value of the largest correction term ΔpMC generated in the past when the correction term ΔpMC is maintained at a constant value and after the correction term ΔpMC starts to decrease. .

According to the processing of step 126, the correction
The term ΔpMC indicates that the state of the braking force control device is the assist pressure increase
After the transition to the state, the output signal pMC changes in the increasing direction.
While “pMCON-pMC” is negative.
As long as it is a value, it is always maintained at "0". Correction term ΔpMC
Is maintained at “0”, the maximum correction term ΔpMC
_MAXIs maintained at "0". Therefore, during this time, the control signal
No. pMC^*Is maintained at a value corresponding to the output signal pMC.
You.

When the output signal pMC starts, the output value pMCON
After the value has decreased to a value smaller than
ON-pMC "changes to a positive value, the correction term ΔpM
C is set to “pMCON-pMC”. And the correction term
ΔpMC is then “pMCON-pMC” is the guard value
Until α, increases as the output signal pMC decreases.
Add. While the correction term ΔpMC continues to increase as described above,
Is the maximum correction term ΔpMC _MAXIs always ΔpMC_MAX= P
Updated while increasing MCON-pMC
You. During this time, the control signal pMC^*(= PMC + ΔpMC
_MAX) Is maintained at a value consistent with pMCON.

Therefore, as shown in FIG. 14, after the assist pressure increase state is started, in the process where the output signal pMC (see the curve to) continues to decrease, the control signal pMC ^* (the curve
^{* To *} ) are always kept at the starting output value pMCON. As described above, in the output signal pMC, the suction interlock decreases after the assist pressure increasing state is started. Therefore, when the assist pressure increasing state is started, the output signal pMC decreases even if the brake operation amount is not reduced. At this time, when the control signal pMC ^* is held at the start output value pMCON as described above, it is prevented that the brake operation amount is erroneously determined to be reduced under the situation where the brake operation amount is increased or held. be able to.

As shown by the curve, when the output signal pMC changes from a decreasing tendency to an increasing tendency, a minimum value pMC _MIN of the output signal pMC occurs. When the minimum value pMC _MIN is detected, the maximum correction term ΔpMC _MAX at that time is ΔpMC _MAX
= Is calculated as pMCON-pMC _MIN. Thereafter, as the output signal pMC increases, the maximum correction term ΔpMC
_MAX is held in pMCON-pMC _MIN. Therefore, when the output signal pMC starts to increase, the control signal pMC ^* (= pMC + ΔpMC _MAX ) then becomes a large value compared to the starting output value pMCON (see the curve ^* ). At this time, assuming that the increment of the output signal pMC from the minimum value pMC _MIN is Δp, the control signal pMC ^* becomes pMC
^* = PMCON + Δp.

As shown by the curve, when the output signal pMC changes from the decreasing tendency to the increasing tendency, it can be determined that the driver requires a larger braking force. Further, the change in the output signal pMC after turning to the increasing tendency accurately reflects the tendency of the driver to brake. According to the above processing, after the output signal pMC has turned to the increasing tendency, that is, after it is detected that the driver is seeking a larger braking force, the control signal pMC ^* is immediately output to the output signal pM.
It can be increased in the same tendency as C. Therefore, according to the above-mentioned process, when the driver requests an increase of the braking force, the control signal pMC ^* while eliminating the influence of the suction interlocking reduced from, accurately reflected in the control signal pMC ^* the intention of the driver Can be done.

As shown by the curve, when the output signal pMC exceeds the guard value α and becomes smaller than the starting output value pMCON, the correction term ΔpMC is fixed to α. For this reason, the maximum correction term ΔpMC _MAX is held at the guard value α even if the output value pMC further decreases. Maximum correction term ΔpM
Output signal pMC with C _MAX held at guard value α
Is further reduced, the control signal pMC ^* thereafter becomes a smaller value than the starting output value pMCON (see curve ^* ). At this time, the control signal pMC ^* is pMC ^* = pMC +
It can be expressed as α.

As shown by the curve, the output signal pMC
If the driver's brake value decreases beyond the
It can be determined that the amount has been reduced. In this case,
The change in the force signal pMC includes the brake operation by the driver.
The trends are accurately reflected. According to the above processing,
After the force signal pMC falls below the guard value α,
That is, it is detected that the driver is requesting a decrease in the braking force.
After that, the control signal pMC ^*Immediately with the output signal pMC.
Can be reduced by the same tendency. Therefore, the above processing
According to the above, when the driver requests a reduction in braking force,
Control signal pMC^*While eliminating the effects of inhaled interlocking
Accurate control signal pMC for driver's intention^*To be reflected in
Can be.

As shown by the curve, when the output signal pMC gradually decreases within the range not exceeding the guard value α, the correction term ΔpMC and the maximum correction term ΔpMC _MAX are both pM
Maintained at CON-pMC. In this case, the control signal pM
C ^* is maintained at the starting output value pMCON (curve
^* See). As shown by the curve, when the output signal pMC gradually decreases within a range not exceeding the guard value α, it can be determined that the driver holds the brake operation amount. According to the above processing, under such circumstances, the control signal pMC ^*
Can be maintained at a constant value. Therefore, according to the above-described processing, when the driver requests the holding of the braking force, the influence of the intake interlocking decrease is eliminated from the control signal pMC ^* ,
The driver's intention can be accurately reflected in the control signal pMC ^* .

In the routine shown in FIG.
If it is determined in step 20 that the assist pressure increasing state has not been realized, the process proceeds to step 13 after step 120.
2 is executed. In step 132, it is determined whether or not this processing cycle is the first cycle after the assist pressure increasing state is ended. As a result, if it is determined that this is the first cycle after the end of the assist pressure increasing state, the process of step 134 is executed next. On the other hand, if it is determined that the current cycle is not the first cycle after the end of the assist pressure increasing state, step 134 is jumped, and the process of step 136 is executed.

In step 134, the holding time timer T
_HOLD is reset to "0". Hold time timer T _HOLD
Is a timer for counting the elapsed time after the end of the assist pressure increasing state. In step 136, the holding time timer T _HOLD is incremented. Step 1
At 38, it is determined whether or not the count time of the holding time timer T _HOLD is equal to or longer than a predetermined time T _TH . The predetermined time T _TH is
After the assist pressure increasing state is terminated, that is, SR
This is the time required for the pulsation generated in the master cylinder pressure P _{M / C} to converge after C _-1 32 and SRC _-236 change from the open state to the closed state. Therefore, T _HOLD ≧ T _TH
Does not hold, it can be determined that the pulsation of the master cylinder pressure PM _{/ C} has not yet converged. If the above determination is made in step 138, the process of step 140 is executed next. On the other hand, if T _HOLD ≧ T _TH already holds, it can be determined that the pulsation of the master cylinder pressure P _{M / C} has already converged. If the above determination is made in step 138, the process of step 142 is executed next.

In step 140, the control signal pMC
The process of holding ^* at the value of the previous processing cycle is executed. When the process of step 140 ends, the current routine ends. In step 142, the control signal pMC ^* is set to a value that matches the output signal pMC. When the process of step 142 ends, the current routine ends.

According to the above processing, as shown in FIG.
After the assist pressure increasing state has ended, (see curve ~) Until the pulsation of the master cylinder pressure P _{M / C} is converged, the control signal pMC ^* can be maintained at a constant value (curve ^* ~ ^* See). Further, according to the above processing, after the pulsation of the master cylinder pressure P _{M / C} has converged (see the curve to 〜), the control signal pMC ^* can be set to a value corresponding to the master cylinder pressure P _{M / C.} (Curve ^* ~ ^*
reference). Therefore, according to the braking force control device of the present embodiment,
Master cylinder pressure P at the end of assist pressure increase state
During the execution of BA control, without being affected by _{M / C} pulsation,
The intention of the driver can always be accurately reflected on the wheel cylinder pressure P _{W / C.}

As described above, in the present embodiment, the control signal pMC ^* is maintained at the output value pMCON at the start until the output signal pMC falls below the guard value α, thereby reducing the suction interlocking of the output signal pMC. Control signal p
Excluded from MC ^* . As described above, in order to eliminate the influence of the inhalation interlocking decrease using the guard value α, the guard value α
Must be larger than the maximum amount of decrease in the output signal pMC caused by the decrease in suction interlock.

However, if the guard value α is unreasonably large, a situation may occur in which the amount of decrease in the output signal pMC does not reach the guard value α for a long time after the brake operation amount is reduced. In this case, a long delay occurs after the brake operation amount is reduced until the change is reflected in the control signal pMC ^* . Therefore, in order to promptly reflect the brake operation on the control signal pMC ^* when the driver reduces the brake operation amount, it is desirable that the guard value α be as small as possible.

For this reason, in the braking force control device of the present embodiment, it is necessary to eliminate the influence of the intake interlocking decrease from the control signal pMC ^* and to accurately reflect the driver's intention in the control signal pMC ^*. It is important to set the value α to a minimum value necessary for absorbing the amount of decrease in the output signal pMC caused by the decrease in intake interlocking. The maximum value of the amount of decrease in the output signal pMC caused by the interlocking of the suction changes depending on the time during which the assist pressure increasing state is continued.
Specifically, the maximum decrease amount becomes larger as the assist pressure increasing state is continued for a longer time. Therefore, it is desirable that guard value α is appropriately changed according to the time during which the assist pressure increasing state is continued.

Further, the output signal pM
The maximum value of the amount of decrease that occurs in C becomes larger as the master cylinder pressure PM _{/ C} at the time when the assist pressure increasing state is started is higher, that is, as the start output value pMCON is larger. Therefore, it is desirable that the guard value α is appropriately changed according to the starting output value pMCON. Hereinafter, with reference to FIG. 15 and FIG. 16, a description will be given of the contents of processing executed by the ECU 10 to realize the above-described function.

FIG. 15 shows a state in which the ECU sets the guard value α.
2 shows a flowchart of an example of a control routine executed by the control routine 10; The routine shown in FIG. 15 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 15 is started, first, the process of step 144 is executed. In step 144, it is determined whether the assist pressure increasing state is realized. As a result, if it is determined that the assist pressure increasing state has not been realized,
This routine ends without any processing being performed. On the other hand, if it is determined that the assist pressure increasing state has been realized, the process of step 146 is executed next. In the present embodiment, as described above, the assist pressure increasing state is realized during the execution of the (I) start increasing pressure mode, the (II) assist pressure increasing mode, or the (V) assist pressure gradual increasing mode. .

In step 146, it is determined whether or not (I) the start pressure increasing mode is being executed. As a result, when it is determined that the start pressure increase mode is being executed, the process of step 148 is executed next. In step 148, a predetermined value alpha ₁ is assigned to the reference guard value alpha _BASE. In the start pressure increasing mode, the assist pressure increasing state and the assist pressure holding state are repeated at the duty ratio Duty1. Predetermined value alpha ₁ is a value set corresponds to the time the assist pressure increasing state is maintained in the course of the repetition.

In step 150, the reference guard value α _BASE
Is multiplied by a correction coefficient f (pMCON) to calculate a guard value α. The correction coefficient f (pMCON) is a value calculated as a function of the starting output value pMCON. FIG. 16 shows an example of a map referred to by the ECU 10 when calculating the correction coefficient f (pMCON). As shown in FIG. 16, the correction coefficient f (pMCON) increases as the output value pMCON at the start increases. Therefore, in step 150, the guard value α increases as the starting output value pMCON increases, that is, as the master cylinder pressure PM _{/ C} at the start of the assist pressure increasing state increases.
Is corrected to a value larger than the reference guard value α _BASE .
When the process of step 150 ends, the current routine ends.

During this routine, if it is determined in step 146 that the start pressure increase mode has not been executed, then the process of step 152 is executed. Step 152
Then, it is determined whether or not (II) the assist pressure increasing mode is being executed. As a result, if it is determined that the assist pressure increasing mode is being executed, then step 154 is executed.
Is performed. On the other hand, when it is determined that the assist pressure increasing mode is not being executed, it can be determined that (V) the assist pressure gradual increasing mode is being executed. In this case, next, the process of step 156 is executed.

In step 154, the reference guard value α _BASE
Is substituted for the predetermined value α ₂ . In the assist pressure increasing mode, the assist pressure increasing state and the assist pressure holding state are repeated at the duty ratio Duty2. Predetermined value alpha ₂ is a value set corresponds to the time the assist pressure increasing state is maintained in the course of the repetition. When the processing in step 154 is completed, the processing in step 150 is performed, and then the current routine is terminated.

In step 156, the reference guard value α _BASE
Is substituted for the predetermined value α ₃ . In the assist pressure gradual increase mode, the assist pressure increase state is maintained for a predetermined time T _MODE2 at the maximum. Predetermined value alpha ₃ is a set value corresponding to a predetermined time T _MODE2. When the processing of step 156 is completed, the processing of step 150 is executed, and then the current routine is terminated.

As described above, according to the above processing, the ECU
10 depending on the mode being executed, ie
The reference guard value α _BASE can be appropriately set to any of α ₁ , α _2, or α ₃ according to the time during which the assist pressure increasing state is maintained. Further, according to the above-described processing, the reference guard value α _{BASE is} appropriately determined according to the start output value pMCON, that is, according to the master cylinder pressure P _{M / C} generated when the assist pressure increasing state is started. And an appropriate guard value α can be calculated. For this reason, according to the braking force control device of the present embodiment, the wheel cylinders 70, 72, 74, 76 of each wheel are not affected by the decrease in the interlocking of the output signal pMC during the execution of the BA control.
The wheel cylinder pressure P that accurately reflects the driver's intention
_{W / C} can be generated.

In the above embodiment, the ECU 10
Executes the processing of steps 122 to 130, thereby realizing the "control signal generation means" according to claim 1, and the ECU 10 executing BA control based on a control signal pMC ^* to execute the control. The "hydraulic pressure control means" according to claim 1 is realized. In the above embodiment, the ECU 10 performs steps 126 and 12
The maximum correction term ΔpMC _MAX is obtained during the processing of step 8 to enable the “minimum value detecting means” and “decrease detecting means” to be executed by the ECU 10 in step 13.
By executing the processing of step S.0, the "first generating means" according to claim 2 is realized.

In the above embodiment, the ECU 10
4. The "second generating means" according to claim 3, wherein the control signal pMC ^* is held at the starting output value pMCON when the output signal pMC continues to decrease during the processing of steps 126 to 130 ^. I have. In the above-described embodiment, the ECU 10 performs the processing in steps 126 to 13 described above.
6. The "fourth generation means" according to claim 5, wherein in the processing of 0, when the output signal pMC falls below the guard value α, the control signal pMC ^* is obtained as pMC + α.
Has been realized.

In the above embodiment, the ECU 10
The "first setting means" according to the sixth aspect and the "second setting means" according to the seventh aspect are realized by executing the processing of steps 146 to 156. In the above embodiment, the ECU 10 executes
The "third setting means" according to claim 8, wherein the "starting fluid pressure detecting means" according to claim 8 performs the processing in step 150.
Have been realized respectively.

In the above embodiment, the ECU 1
0 executes the processing of steps 132 to 140, and the “fifth generation means” according to claim 9 executes the processing of step 142 to “sixth generation means” according to claim 9. Has been realized respectively. Next, a second embodiment of the present invention will be described with reference to FIGS. The braking force control device according to the present embodiment has an ECU 10 in the system configuration shown in FIG.
Then, it is realized by executing the routine shown in FIG.

FIG. 17 is a flowchart showing an example of a control routine executed by the ECU 10 in this embodiment.
The routine shown in FIG. 17 is the same as the routine shown in FIG. 13 except that the processing of step 144 is performed after the processing of step 126 is performed. Hereinafter, the description of the same portions as those of the routine shown in FIG. 13 will be omitted.

Step 144 in the routine shown in FIG.
Then, the control signal pMC ^* is calculated. Step 14
In 4, the control signal pMC ^* is calculated by adding the correction term ΔpMC to the output signal pMC. When the process of step 144 ends, the current routine ends. FIG. 18 is a diagram showing a comparison between the output signal pMC and the control signal pMC ^* calculated by the above processing. The dashed-dotted line and the solid line indicated by ^* in FIG. 18 respectively appear in the output signal pMC when the assist pressure increasing state is executed under the condition that the brake operation amount is increased. 5 shows a change and a change of the control signal pMC ^* corresponding to the output signal pMC.

The dashed-dotted line shown in FIG. 18 and the solid line shown with ^* are output when the assist pressure increasing state is executed while the brake operation amount is held. The change appearing in the signal pMC and the change in the control signal pMC ^* corresponding to the output signal pMC are shown. Similarly, the alternate long and short dash line shown in FIG.
^The solid lines indicated by * correspond to the change that appears in the output signal pMC when the assist pressure increasing state is executed in a situation where the brake operation amount is reduced, and the output signal pMC, respectively. The change of the control signal pMC ^* to be performed is shown.

As shown in FIG. 18, after the assist pressure increasing state is realized, the output signal pMC temporarily decreases due to the suction interlocking reduction regardless of the increase or decrease of the brake operation amount. Therefore, immediately after the assist pressure increasing state is started, the output signal pMC becomes equal to or less than the starting output value pMCON. According to the processing of step 126, when the output signal pMC is equal to or less than the start output value pMCON and the decrease in the output signal is less than the guard value, that is, the output signal pMC
If Mc satisfies “pMCON ≧ pMC ≧ pMCON-α”, the correction term ΔpMC is calculated as “pMCON-pMC”. In this case, in step 144, the control signal pMC ^* is set to a value that matches the start output value pMCON. Therefore, as shown in FIG. 18, immediately after the assist pressure increasing state is started, the output value pMC is maintained at the start time output value pMCON for a predetermined period regardless of the increase or decrease of the brake operation.

[0131] After the assist pressure increasing state is started, during the process of inhalation conjunction decrease in the output signal pMC (see curve ~) occurs, the control signal as described above pMC ^* (curve ^* ~ ^* see) to start output value pMCON In the situation where the brake operation amount is increased or held, it can be prevented that the brake operation amount is erroneously determined to be reduced.

As shown by the curve in FIG. 18, when the driver increases the brake operation amount, the output signal p
MC temporarily decreases due to a decrease in inhalation interlocking and then starts to increase. In this case, the output signal pMC eventually reaches a value exceeding the starting output value pMCON. In the above step 126, the output signal pMC becomes “pMC> pMCO
"If it meets the correction term ΔpMC is" N is calculated as 0 ". In this case, in the step 144, as indicated by a curve ^* in FIG. 18, the control signal pMC ^* output signal p
It is calculated to a value that matches MC. As described above, according to the above-described processing, when the driver increases the brake operation amount, the driver's intention can be accurately determined while eliminating the influence of the suction interlocking decrease from the control signal pMC ^*.
* Can be reflected in

As shown by the curve in FIG. 18, when the driver reduces the brake operation amount, the output signal p
MC falls below the guard value α. Step 1 above
26, the output signal pMC is “pMCON-α> pM
C ”, the correction term ΔpMC becomes“ α. ”In this case, in the above step 144, the curve ^{* in} FIG.
, The control signal pMC ^* is calculated as “pMC + α”. As described above, according to the above-described processing, when the brake operation amount is increased by the driver, the driver's intention is accurately determined while eliminating the influence of the intake interlocking decrease from the control signal pMC ^{*. *} Can be reflected in

As shown by the curve in FIG. 18, when the driver holds the brake operation amount, the output signal pMC changes gradually within a range not exceeding the guard value α. In this case, according to the above processing, the control signal pMC ^* is maintained at the starting output value pMCON for a long period of time, as shown by the curve ^* in FIG. As described above, according to the above-described processing, when the driver intends to maintain the brake operation amount, the driver's intention can be accurately determined while eliminating the influence of the suction interlock reduction from the control signal pMC ^{*. *} Can be reflected in

In the above embodiment, the ECU 10
Executes the processing of steps 122, 124, 126 and 144 shown in FIG. 17, thereby realizing the "control signal generating means" according to the first embodiment.
10 implements the BA control based on the control signal pMC ^* , thereby realizing the "hydraulic pressure control means" according to claim 1.

In the above embodiment, the ECU 1
0 is the control signal pMC when the output signal pMC continues to decrease in the processing of steps 126 and 130.
By holding ^* in the start output value pMCON, the "second generating means" according to claim 3 is realized. Further, in the above embodiment, the ECU 10 determines that the output signal pM
When C exceeds the output value pMCON at the start, the "third generation means" according to claim 4 is realized by setting the control signal pMC ^* to a value that matches the output signal pMC.

[0137]

As described above, according to the first aspect of the present invention, there is provided a system configuration including a pump for sucking brake fluid from a hydraulic passage communicating the master cylinder and the wheel cylinder, and a brake assist system. It is possible to realize a braking force control device that can appropriately increase and decrease the wheel cylinder pressure according to the driver's intention during the execution of the control.

According to the second aspect of the present invention, when the driver increases the brake operation amount, the control signal eliminates the influence of the intake interlocking decrease, and the control signal accurately indicates the driver's intention. Can be reflected. According to the third aspect of the present invention, it is possible to prevent the control signal from changing due to the influence when the output signal decreases due to the suction interlocking decrease.

According to the fourth aspect of the present invention, similarly to the second aspect of the present invention, when the driver increases the brake operation amount, the control signal eliminates the influence of the intake interlocking decrease. In addition, the driver's intention can be accurately reflected in the control signal. According to the fifth aspect of the present invention, when the driver is reducing the brake operation amount, the intention of the driver is accurately reflected on the control signal while eliminating the influence of the suction interlock reduction from the control signal. be able to.

According to the sixth to eighth aspects of the present invention, the guard value for determining the width of the reduction of the output signal which is not reflected in the control signal is always a necessary and sufficient value for eliminating the influence of the interlocking of the suction. Can be. Therefore, according to the present invention,
While properly eliminating the influence of the suction interlock decrease from the control signal,
The driver's intention can be accurately reflected in the control signal.

According to the ninth aspect, before and after the suction of the brake fluid by the pump is stopped,
The brake operation amount can be accurately reflected in the control signal. According to the tenth aspect of the present invention, it is possible to generate a control signal that accurately reflects the driver's braking operation, despite the fact that the output signal of the hydraulic pressure sensor decreases with the operation of the pump. .

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an assist pressure increasing state of the braking force control device shown in FIG. 1;

FIG. 3 is a diagram showing an assist pressure holding state of the braking force control device shown in FIG. 1;

FIG. 4 is a diagram showing a reduced assist pressure state of the braking force control device shown in FIG. 1;

5 is a diagram illustrating changes that occur in a master cylinder pressure PM _{/ C} and a wheel cylinder pressure _{PW / C} when an emergency braking operation is performed in the braking force control device illustrated in FIG. 1;

FIG. 6 is a table showing a control mode executed after a start pressure increase mode when BA control is executed in the braking force control device shown in FIG. 1;

FIG. 7 is a table showing a control mode executed next to the assist pressure increasing mode when BA control is executed in the braking force control device shown in FIG. 1;

FIG. 8 is a table showing a control mode executed next to the assist pressure reduction mode when BA control is executed in the braking force control device shown in FIG. 1;

FIG. 9 is a table showing a control mode executed next to the assist pressure holding mode when BA control is executed in the braking force control device shown in FIG. 1;

FIG. 10 is a table showing a control mode executed next to the assist pressure gradual increase mode when BA control is executed in the braking force control device shown in FIG. 1;

11 is a table showing a control mode that is executed after the assist pressure gradual decrease mode when BA control is executed in the braking force control device shown in FIG. 1;

FIG. 12A is a waveform that appears in an output signal pMC of a hydraulic pressure sensor before and after an assist pressure increase state is realized. FIG. 12 (B) shows the reservoir cut solenoids SRC- ₁ and SRC before and after the assist pressure increasing state is realized.
₆ is a time chart showing a change occurring in _-2 . FIG.
(C) is a time chart showing changes occurring in the pump before and after the assist pressure increasing state is realized.

FIG. 13 shows a control signal pMC according to the first embodiment of the present invention.
⁹ is a flowchart of an example of a control routine executed to calculate ^* .

FIG. 14 is a graph showing an output value pMC (curve 液) output from a hydraulic pressure sensor and a control signal pMC ^* (curve ^*演算) calculated corresponding to the output value pMC (curve 〜) in the first embodiment of the present invention
^* ) And FIG.

FIG. 15 is a flowchart of an example of a control routine executed to calculate a guard value α in the first embodiment of the present invention.

FIG. 16 shows a coefficient f during execution of the control routine shown in FIG.
It is an example of a map referred to for obtaining (pMCON).

FIG. 17 shows a control signal pMC according to the second embodiment of the present invention.
⁹ is a flowchart of an example of a control routine executed to calculate ^* .

FIG. 18 shows output values pMC (curves （) output from the hydraulic pressure sensors and control signals pMC ^* (curves ^*演算) calculated corresponding thereto in the second embodiment of the present invention.
^* ) And FIG.

[Explanation of symbols]

Reference Signs List 10 Electronic control unit (ECU) 12 Brake pedal 18 Master cylinder 26 First hydraulic passage 28 Second hydraulic passage 29 Hydraulic pressure sensor 100, 102 Pump 70, 72, 74, 76 Wheel cylinder pMC Output signal pMC ^* Control signal pMCSTA Output value at change pMCON Output value at start ΔpMC correction term ΔpMC _MAX maximum correction term α guard value α _BASE reference guard value f (pMCON) coefficient

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideyuki Aizawa 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Masahiro Hara 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (10)

[Claims] A hydraulic pressure sensor for generating an output signal corresponding to a master cylinder pressure; and a pump for sucking brake fluid from a hydraulic pressure passage communicating between the master cylinder and a wheel cylinder. Is executed, a brake force control device that performs a brake assist control for supplying a hydraulic pressure discharged from the pump to a wheel cylinder, wherein the output is output when the pump sucks brake fluid from the hydraulic pressure passage. Braking force control, comprising: a control signal generation unit that generates a control signal by correcting a decrease in a signal; and a hydraulic pressure control unit that performs the brake assist control using the control signal. apparatus. 2. The braking force control device according to claim 1, wherein the control signal generating unit detects a minimum value generated in an output signal of the hydraulic pressure sensor after the pump starts sucking brake fluid. A minimum value detection unit, a decrease detection unit that detects a decrease in the output signal until the minimum value is reached, and after the minimum value is detected, the output signal is determined based on the decrease. And a first generating means for generating the control signal by correcting the braking force. 3. The braking force control device according to claim 1, wherein the control signal generating means includes a second generating means for holding the control signal at a constant value after the suction of brake fluid by the pump is started. A braking force control device comprising: 4. The braking force control device according to claim 3, wherein the control signal generating means matches the control signal with the output signal when an output signal of the hydraulic pressure sensor exceeds a predetermined value. A braking force control device comprising means. 5. The braking force control device according to claim 3, wherein the control signal generating means outputs the control signal to the output signal when the output signal of the hydraulic pressure sensor falls below a guard value. A braking force control device comprising: a fourth generation unit that sets a value obtained by adding a guard value. 6. The braking force control device according to claim 5, wherein the control signal generation unit sets the guard value based on a time during which the pump continuously sucks brake fluid. A braking force control device comprising means. 7. The braking force control device according to claim 5, wherein the hydraulic pressure control means realizes a plurality of modes in which the time during which the brake fluid is continuously sucked by the pump is different from each other, and the control signal A braking force control device, characterized in that the generation means includes second setting means for setting the guard value based on a mode executed by the hydraulic pressure control means. 8. The braking force control device according to claim 5, wherein the control signal generating means is configured to output the control signal based on an output signal output from the hydraulic pressure sensor when the pump starts sucking brake fluid. A braking force control device comprising: a starting hydraulic pressure detecting unit that detects a starting hydraulic pressure; and a third setting unit that sets the guard value based on the starting hydraulic pressure. 9. The braking force control device according to claim 1, wherein the control signal generation means transmits the control signal until a predetermined time elapses after the suction of the brake fluid by the pump is stopped. A braking force control device comprising: a fifth generation unit that holds a constant value; and a sixth generation unit that matches the control signal with the output signal after the predetermined time has elapsed. 10. The braking force control device according to claim 1, further comprising valve means between the master cylinder and the wheel cylinder, wherein the hydraulic pressure sensor and the suction side of the pump are connected between the valve means and the master cylinder. A braking force control device, wherein the braking force control device is communicated with the braking force control device.