JP3221146B2 - Braking force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device,
In particular, the present invention relates to a braking force control device that controls a braking force by driving a brake operating member by an intake negative pressure generated in an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, there has been known a braking force control device which generates a brake fluid pressure by driving a brake operating member using an intake negative pressure generated in an internal combustion engine as a drive source, and controls a braking force by the brake fluid pressure. (JP-A-61-175130).

[0003] The apparatus described in the above-mentioned publication stores a negative pressure chamber capable of accumulating an intake negative pressure of an internal combustion engine and maintaining the same at an internal pressure equal to the intake negative pressure, and appropriately introducing the intake negative pressure and the atmosphere to a predetermined internal pressure. And a brake booster including a master cylinder for converting a differential pressure generated between the negative pressure chamber and the variable pressure chamber into a hydraulic pressure, and a brake operating member.
The brake operation member includes a piston for separating the negative pressure chamber and the variable pressure chamber, a piston for separating the space in the master cylinder from the brake fluid, and a push rod connecting the pistons.

Therefore, for example, when the negative pressure chamber and the variable pressure chamber are maintained at the same pressure, no force acts on the piston, so that the brake mechanism does not operate. On the other hand, if the pressure in the variable pressure chamber is set to atmospheric pressure while the negative pressure chamber is maintained at negative pressure, a thrust corresponding to the differential pressure acts on the piston or push rod, and each brake mechanism is increased to a pressure corresponding to the thrust. The supplied brake pressure is supplied.

That is, according to the braking force control device described in the above publication, each brake mechanism is supplied with a hydraulic pressure corresponding to the differential pressure between the negative pressure chamber and the variable pressure chamber of the brake booster. By releasing the oil to the atmosphere to increase the hydraulic pressure, the braking force can be increased,
By controlling the amount of air introduced into the variable pressure chamber, the braking force can be easily controlled.

[0006]

By the way, the vehicle is shaken.
When braking, the lower the vehicle speed, the more the brakes
The shock caused by the effect is felt great. Also,
Generally, a strong braking force is required during low-speed driving
Often, fine adjustment of braking force is required.
No. Therefore, regarding the relationship between the vehicle speed and the braking force,
The lower the speed, the lower the booster capacity of the brake booster
There is a need.

[0007] However , in the conventional device, it is necessary to respond to the vehicle speed.
The booster capacity of the brake booster
Rather, there has been a problem that it can not ensure a stable braking force corresponding to the operation feeling of the driver.

The present invention has been made in view of the above points, and calculates a drive gain of a brake operating member based on a vehicle speed, and further drives the brake operating member based on the calculation result to thereby control the driver's operation. Cheap for the senses
It is possible to obtain a boss was braking force, thus an object to provide a brake force control apparatus which can improve the stability of the braking force.

[0009]

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

As shown in FIG.
A vehicle speed detecting means for detecting a vehicle speed in a braking force control device for driving a brake operating member M20 by a negative pressure supplied from a negative pressure supply source M10 to generate a brake fluid pressure and controlling a braking force by the brake fluid pressure. M25, and a drive gain calculating means M50 for calculating a drive gain of the brake operating member M20 based on the detection value detected by the vehicle speed detecting means M25 so as to decrease as the vehicle speed decreases. It is a feature. According to a second aspect of the present invention, in the braking force control device according to the first aspect, an engine speed detecting means M30 for detecting a speed of the internal combustion engine and a throttle opening detecting means for detecting an opening of a throttle valve. and M40, wherein the driving gain calculation unit M50, the vehicle speed detecting hands
Detection value detected by the step M25, the detection value detected by the engine speed detecting means M30, and the throttle opening degree detecting means M40 on the detection values detected by have group Dzu <br/> by, as the vehicle speed is smaller as smaller, so as to decrease the larger number of revolutions of the internal combustion engine, and characterized in that calculating the driving gain of the brake operating member M20 so as to decrease as the degree of opening of the throttle valve is small is there.

[0011]

According to the present invention, the drive gain is calculated.
The drive gain of the brake operating member is calculated by the means based on the value detected by the vehicle speed detecting means . Then, the supply of the intake negative pressure is controlled based on the calculated drive gain. Therefore, drive the brake operating member according to the vehicle speed.
Movement for stability that corresponds to the driver's operational feeling
Can generate the brake fluid pressure
As a result, the braking force is controlled to a predetermined braking force with good stability.
Can be

Further, in the invention according to claim 2, the driving
The gain calculating means, together with the value detected by the vehicle speed detecting means,
Detection value by engine speed detection means and throttle opening detection
Output value of at least one of the detected values
The drive gain of the brake operating member is calculated based on the calculated value.
Then, based on the calculated drive gain, the intake negative pressure
Is controlled. Therefore, brake operation according to vehicle speed
By driving the working members,
To generate a stable and stable brake fluid pressure.
As well as the brake operation unit regardless of fluctuations in the intake negative pressure
By generating a predetermined thrust with good stability on the material,
A constant brake fluid pressure can be generated. This
Therefore, the braking force is controlled to a predetermined braking force with higher stability.
Can be

[0013]

FIG. 2 is a configuration diagram of a brake system incorporating a braking force control device according to a first embodiment of the present invention.
This system includes the braking force control device according to the present invention for a physically handicapped person and also has a commonly used brake system for a healthy person.

In FIG. 2, reference numeral 1 denotes an electronic control unit (control ECU) including the above-mentioned internal pressure control means. Control EC
A mode changeover switch 2 for switching between the physically disabled mode and the healthy person mode is connected to U1, and whether or not to operate the braking force control device of the present embodiment is determined by the output signal of the mode changeover switch 2. .

Reference numerals 3 and 4 denote a vehicle speed sensor for outputting a pulse signal corresponding to the vehicle speed, and an engine speed sensor for outputting a pulse signal corresponding to the rotation speed of the internal combustion engine. Equivalent).
Reference numeral 5 denotes an operation lever in the physically handicapped person mode. The operation lever 5 is used for instructing acceleration / deceleration of the vehicle, and supplies a predetermined acceleration / deceleration instruction amount signal to the control ECU 1 by a driver's operation.

In FIG. 2, FL, FR and RL, RR denote left and right front wheels and left and right rear wheels, respectively. Each of these wheels is independently provided with a brake mechanism 6 to 9 that operates by hydraulic pressure to brake each wheel. The brake mechanisms 6 to 9 are set so as to exert a braking force only when the supplied hydraulic pressure becomes high.

The left and right front wheels FL and FR are provided with hydraulic pressure sensors 10 and 11 for detecting actual brake pressures actually supplied to the brake mechanisms 6 to 9, respectively. And
These oil pressure sensors 10 and 11 supply signals corresponding to the detected oil pressure to the control ECU 1.

In this embodiment, the throttle valve 13 controls the amount of intake air supplied to the internal combustion engine.
Is also electronically controlled. Reference numeral 20 denotes an electronic control throttle used in this embodiment. The electronic control throttle 20 includes a DC motor (DC-MOTOR) 21.
As a drive source, and adjusts the opening of the throttle valve 13 based on a throttle opening signal output from the control ECU 1 in accordance with the acceleration / deceleration instruction amount supplied from the operation lever 5.

That is, the throttle valve 13 is driven not only by the accelerator pedal 12 but also by the wire 14. The end of the wire 14 is connected to a shaft 23 that rotates in conjunction with an electromagnetic clutch 22 that transmits the rotation of the DC motor 21.

Therefore, the electromagnetic clutch 22 is connected to the DC motor 2
When the DC motor 21 rotates, the wire 14 opens and closes the throttle valve 13 as the DC motor 21 rotates, and the opening of the throttle valve 13 fluctuates. The electromagnetic clutch 22 operates according to a control signal supplied from the control ECU 1, and disconnects or connects the DC motor 21 and the throttle valve 13. That is, when the electromagnetic clutch 22 is disconnected, the DC motor 2
The throttle valve 13 does not open with one rotation.

The electronic control throttle 20 has a
The opening sensor 2 detects the actual opening of the throttle valve 13 based on the rotation angle of the electromagnetic clutch 22 as shown in FIG.
4 are incorporated. Then, the opening degree sensor 24 controls the detected actual opening degree data of the throttle valve 13 to control E.
Sending to CU1.

In FIG. 2, reference numeral 30 indicates an electronically controlled brake system which is a main part of the present embodiment. The electronic control brake system 30 is premised on being mounted on a vehicle for the physically handicapped as described above. Here, in designing a vehicle for the physically handicapped, ensuring good operability is one of the important issues. Above all, operability when braking the vehicle is the most important item from the viewpoint of ensuring safety.

Therefore, in the present embodiment, in order to secure a reliable braking force with a small operation force, the actual brake pressure supplied to the brake mechanisms 6 to 9 disposed on each wheel can be electrically controlled. An electronically controlled brake system 30 is employed. In FIG. 2, reference numeral 31 denotes the electronic control brake system 30.
3 shows a brake booster (control B / B) which is a part of a braking force control device, which is a main part of FIG. 3, and as shown in FIG. 3, a negative pressure chamber 31a, a variable pressure chamber 31b, a master cylinder 31c, and a brake operating member 32 ( Brake operating member M20).
Is composed of a piston 32a separating the negative pressure chamber 31a and the variable pressure chamber 31b, a piston 32b disposed in the master cylinder 31c, and a push load 32c connecting the pistons 32a and 32b.

As shown in FIG. 2, the negative pressure chamber 31a communicates with a downstream side of a throttle valve in an intake pipe of an internal combustion engine (not shown) through a check valve 32, so that a negative pressure of the intake air (engine vacuum) is constantly maintained during operation of the internal combustion engine. Receive supply. The check valve 32 (see FIG. 2) is a one-way valve that allows only the flow from the negative pressure chamber 31a to the internal combustion engine. For this reason, even if the internal combustion engine stops and the intake negative pressure disappears, the negative pressure in the negative pressure chamber 31a is maintained as it is.

On the other hand, the transformation chamber 31b has two air introduction valves E
It communicates with the atmosphere through the ACVs 1 and 2 and the air filters 33 and 34, and communicates with the intake pipe of the internal combustion engine through the negative pressure supply valve EACV3 and the check valve 32. Therefore, the pressure in the transformation chamber 31b is equal to the atmospheric introduction valve EACV.
When the negative pressure introduction valve EACV3 is opened by closing the valves 1 and 2, the pressure becomes equal to the internal pressure of the negative pressure chamber 31a. When the EACV3 is opened and the EACV3 is closed, the pressure becomes atmospheric pressure.

The master cylinder 31c is a cylinder that supplies a hydraulic pressure corresponding to the pressure difference between the negative pressure chamber 31a and the variable pressure chamber 31b to each of the brake mechanisms 6-9. That is, when air is introduced into the transformation chamber 31b,
Piston 32 for separating negative pressure chamber 31a and variable pressure chamber 31b
In a, a thrust is generated from the transformation chamber 31b toward the negative pressure chamber 31a.

The thrust is applied to the push rod 32c connected to the piston 32a and to the master cylinder 3c.
The hydraulic pressure is converted into a hydraulic pressure via a piston 32b provided in 1c and supplied to each of the brake mechanisms 6 to 9 as a boosted brake pressure. On the other hand, when the inside of the variable pressure chamber 31b is maintained at the same pressure as the negative pressure chamber 31a, the master cylinder 3
No force acts on the piston 32b in 1c. For this reason, the brake mechanisms 6 to 9 are not supplied with a brake pressure high enough to drive them, and no braking force acts on each wheel.

In this embodiment, the negative pressure chamber 3
1 a communicates with the variable pressure chamber 31 b via a negative pressure control valve (VSV) 35. Therefore, for example, when the healthy person mode is selected, the VSV 35 is opened to maintain the internal pressure of the negative pressure chamber 31a and the internal pressure of the variable pressure chamber 31b always at the same pressure. The boost function does not operate, and even if the operation lever 5 is erroneously operated, the brake boost function does not operate.

Reference numeral 15 denotes a brake pedal provided corresponding to a normal person mode. This brake pedal 1
5 is the master cylinder 16 for the brake pedal 15
And is supplied to the high select device 36 of the electronic control brake system 30. Here, the high select device 36 uses the higher one of the hydraulic pressures supplied from the two master cylinders 16 and 31c to each of the brake mechanisms 6-9.
It is a device to transmit to.

A known anti-lock brake system (ABS) is incorporated in the brake system of the present embodiment, and the hydraulic pressure transmitted from the high select device 36 is transmitted through the ABS mechanism 17 to each of the brake mechanisms 6 to 6. 9.

The control ECU 1 includes a brake mechanism 6.
-9 are activated and the vehicle is braking, a stop lamp (STOP lamp) 18 that lights up, and a mode display lamp 19 that indicates whether the selected mode is the disabled person mode or the healthy person mode. Is connected and control E
The driving state of the CU 1 and the like can be determined by the driver or the like.

FIG. 4 shows a flowchart of a main routine executed by the control ECU 1 of the braking force control device according to the present embodiment. Hereinafter, the operation of the apparatus of this embodiment will be described with reference to FIG.

When the main routine shown in FIG. 4 starts,
First, at step 100, it is determined whether or not the mode changeover switch 2 is in the disabled mode. Here, when the mode changeover switch 2 does not represent the disabled mode, that is, when the driver is a healthy person, the control B / B 31 is used from the viewpoint of preventing sudden braking due to the erroneous operation of the operation lever 5 described above. Must be separated from the brake mechanisms 6 to 9. Therefore, if it is determined in step 100 that the mode is not the disabled mode, the process loops without performing the processing of steps 102 and 104 described later. On the other hand, if it is determined in step 100 that the mode changeover switch 2 is in the physically handicapped person mode, the process proceeds to step 102 to perform brake control according to the acceleration / deceleration instruction amount of the operation lever 5.

FIG. 5 is a flowchart showing a subroutine of the brake control executed in step 102. Hereinafter, the operation of the braking force control device according to the present embodiment will be described with reference to FIG.

As described above, the electronic control brake system 30 of the present embodiment utilizes the differential pressure between the internal pressure of the negative pressure chamber 31a of the control B / B 31 and the internal pressure of the variable pressure chamber 31b, as described above. To 9 are boosted. Therefore, the greater the differential pressure between the negative pressure chamber 31a and the variable pressure chamber 31b, the greater the actual brake pressure supplied to the brake mechanisms 6-9.

On the other hand, EACVs 1 to 3 for controlling conduction between the variable pressure chamber 31b and the atmosphere and the intake pipe are control valves for changing the opening area of the conduction section in accordance with a flow rate instruction signal supplied from the control ECU 1. For this reason, even if the conduction area is the same, the atmosphere introduction valve EACV differs depending on whether the negative pressure stored in the variable pressure chamber 31b, that is, the intake negative pressure is large or small.
A difference occurs in the amount of air introduced when valves 1 and 2 are opened. Similarly, when the negative pressure supply valve EACV3 is opened while the atmosphere is being introduced into the variable pressure chamber 31b, a difference in the amount of air flowing out of the variable pressure chamber 31b to the intake pipe occurs due to the magnitude of the negative intake pressure. become.

That is, the sense of operation of the operating lever 5 by the driver and the braking force exerted by each of the brake mechanisms 6 to 9, that is, the actual brake pressure supplied from the master cylinder 31 c by driving the brake operating member 32. In order to make them the same, by controlling the amount of air introduced into the variable pressure chamber 31b when the EACV1 to 3 is opened or the amount of air flowing out of the variable pressure chamber 31b regardless of the fluctuation of the intake negative pressure of the internal combustion engine, It is necessary to have a configuration capable of controlling the braking force.

Therefore, in the present embodiment, the engine speed and the actual throttle opening, which are the factors of fluctuation of the intake negative pressure generated in the intake pipe of the internal combustion engine, are detected, and the intake negative pressure is estimated from these detected values. Then, the opening areas of the EACVs 1 to 3 when the valves are opened are corrected based on the estimated magnitude of the intake negative pressure.

Therefore, as shown in FIG. 5, when the mode changeover switch 2 is confirmed to be in the disabled mode and this routine is started, first, in step 200, the output signal of the engine speed sensor 4 Revolution N
E is detected. Next, the routine proceeds to step 202, where the opening degree sensor 2
4, the actual throttle opening THR is detected.

Here, the intake negative pressure E / GB is determined by the engine speed N
The larger the value of E is, the larger the value is, and the smaller the throttle opening THR is, the larger the value can be obtained as a function of NE and THR. Therefore, in the present embodiment, a map as shown in FIG.
The intake negative pressure E / GB generated in the intake pipe of the internal combustion engine is obtained by referring to the map based on E and THR.
(Step 204).

By the way, when braking the vehicle,
The lower the vehicle speed, the greater the shock due to the braking effect. In general, during low-speed running, fine adjustment of the braking force is often required rather than a strong braking force. Therefore, in order to make the driver's operation sensation correspond to the braking sensation of the vehicle in the system of the present embodiment, it is also necessary to perform correction according to the vehicle speed.

Therefore, in this embodiment, after the intake negative pressure E / GB of the internal combustion engine is estimated in step 204, the process proceeds to step 206, where the vehicle speed _VW is calculated based on the output signal of the vehicle speed sensor 3.

Thus, the intake negative pressure E / GB and the vehicle speed V
After estimating the _W, then based on the E / GB and the vehicle speed V _W, obtains the correction gain G _B and G _VW for introducing a predetermined amount of air into the variable pressure chamber 31b.

That is, when the atmosphere introduction valves EACV1 and EACV2 are opened to introduce the atmosphere into the transformation chamber 31b, the transformation chamber 31b
The amount of air introduced into the EACV1 and EACV2 is a function of the opening area when the EACV1 and EACV2 are turned on and the pressure in the variable pressure chamber 31b before the EACV1 and EACV2 are opened, that is, the intake negative pressure E / GB of the internal combustion engine. The larger the opening area of the EACVs 1 and 2,
Also, the larger the intake negative pressure E / GB, the more air is introduced.

Accordingly, in order to introduce a predetermined amount of air into the variable pressure chamber 31b regardless of the magnitude of the intake negative pressure E / GB,
The larger the intake negative pressure E / GB, the smaller the opening areas of the EACVs 1 and 2 need to be corrected. Thus, in this embodiment, it may be stored in advance in the control ECU1 a map shown in FIG. 7, and calculates the correction gain G _B by reference intake negative pressure E / GB estimated in step 204 ( Step 208).

[0046] In addition, the relationship between vehicle speed V _W and the braking force, it is necessary to reduce the boost capability of the control B / B as the vehicle speed V _W is slow as described above. That is, a large amount of air needs to be introduced into the variable pressure chamber 31b during high-speed traveling, and a small amount of air must be introduced into the variable pressure chamber 31b during low-speed traveling. Therefore, in the present embodiment, for example, the relationship between the vehicle speed V _W and the correction gain G _VW as shown in FIG. 8 is set in advance, and the correction gain G _VW is obtained by referring to this relationship with the vehicle speed V _W. (Step 210).

Next, at step 212, a required brake pressure TBPL corresponding to the braking force required by the driver is calculated,
The difference ΔBP from the actual brake pressure detected by the oil pressure sensors 10 and 11 is detected. Here, if ΔBP is a positive value, the driver is requesting a stronger braking force,
If ΔBP is not a positive value, it means that the driver intends to weaken the braking force.

Incidentally, the actual brake pressure BPR supplied to the brake mechanisms 6 to 9 is equal to the negative pressure chamber 31 as described above.
3A shows a pressure corresponding to a differential pressure generated between the variable pressure chamber 31a and the variable pressure chamber 31b. Therefore, as the actual brake pressure BPR increases, the pressure difference between the negative pressure chamber 31a and the variable pressure chamber 31b increases, that is, the pressure in the variable pressure chamber 31b should be closer to the atmospheric pressure.

On the other hand, when the air introduction valves EACV1 and EACV2 are opened, the amount of air introduced into the transformation chamber 31b per unit time becomes smaller as the pressure in the transformation chamber 31b becomes closer to the atmospheric pressure. On the other hand, when the negative pressure introduction valve EACV3 is opened to supply the intake negative pressure into the variable pressure chamber 31b, the amount of air flowing out of the variable pressure chamber 31b increases as the pressure in the variable pressure chamber 31b approaches the atmospheric pressure, that is, the actual amount of air. The larger the brake pressure BPR, the larger the amount.

Therefore, in order to make the actual change in the braking force correspond to the driver's operational feeling, it is necessary to correct the actual brake pressure BPR at each moment. That is,
When the driver intends to increase the braking force, the larger the actual brake pressure BPR at that time is, the larger the opening area of the EACVs 1 and 2 at the time of opening the valve is, and the driver intends to reduce the braking force. In this case, as the actual brake pressure BPR increases, the opening area of the EACV 3 at the time of opening the valve needs to be corrected smaller.

Therefore, in this embodiment, when ΔBP is detected in step 212, it is subsequently determined whether or not the value is a positive value (step 214). Then, calculates a correction gain G _BPU for pressure increase the actual brake pressure BPR if ΔBP> 0 (Step 21
6), if ΔBP ≦ 0, the driver has decided to calculate the correction gain G _BPD for decompressing the actual brake pressure BPR it is determined that they have the intention to weaken the braking force (step 218).

In this embodiment, each of the correction gains G _BPU and G _BPD is set to the actual brake pressure B B as described above.
Paying attention to the value determined as a function of the PR, the control ECU 1 previously _{sends the} G _BPU or G B shown in FIGS.
Storing a map representing the relationship between the _BPD and BPR advance, is set to ask the G _BPU and G _BPD this by reference in actual brake pressure BPR.

[0053] After calculating the correction gain G _BPU or G _BPD for correction gain G _B, the correction gain G _VW, actual brake pressure BPR with respect to the vehicle speed relative to the intake negative pressure of the thus engine, by integrating these correction gain A total correction gain _GBRK is obtained (step 220). Incidentally, if it is determined that ΔBP> 0 in step 214 in this case, the total correction gain _{G BRK = G B * G VW} * G
_BPU next, also if it is determined that ΔBP ≦ 0, the total correction gain _{G BRK = G B * G VW} * G BPD.

In the next steps 222 and 224, the opening areas TAF1 to TAF3 of the EACVs 1 to 3 to be secured to allow a desired amount of air to flow through the EACVs 1 to 3 are calculated using the total correction gain G _BRK . Here, TAF1 = TAF
2 = TAF / 2 while TAF3 = TAF means that the introduction of the atmosphere into the transformation chamber 31b is performed by the atmosphere introduction valve EA.
This is because the intake negative pressure is performed only from the negative pressure introduction valve EACV3, while the control is performed simultaneously from CV1 and CV2.

In order to realize a braking force consistent with the driver's operational feeling, the opening areas TAF1 to TAF3 of the EACV1 to 3 are realized.
Is obtained by integrating the difference between the driver's requested brake pressure TBPR and the actual brake pressure BPR, that is, ΔBP calculated in step 212 and the total correction gain G _BRK ( Step 2
22).

As shown in the characteristic diagram of FIG. 10, the air introduction valves EACV1, EACV2 and the negative pressure introduction valve 3 have a characteristic that they open with an opening area TAF corresponding to the current I of the supplied flow control signal. Have. Therefore, when the opening area of each of the introduction valves EACV1 to 3 is calculated in step 224, the process proceeds to step 226, and the opening area TAF is calculated.
Calculate the current values I _{1 to} I ₃ to be supplied in order to realize 1 to ₃ .

When it is desired to increase the braking force based on the operation of the operation lever 5 by the driver, for example, currents I ₁ and I ₂ are supplied to the air introduction valves EACV1 and EACV2, respectively, and the braking force is reduced. Negative pressure introduction valve EAC if you want to weaken
By supplying a current I ₃ relative to V3 (step 228) and terminates the current process.

When the brake control routine is completed, the process returns to the main routine again, and throttle control is performed in step 104 in FIG. Hereinafter, the throttle control in this embodiment will be described with reference to the flowchart of the throttle control subroutine shown in FIG.

In the apparatus of this embodiment, a feedback system is formed by using an opening sensor 24 for detecting the actual opening of the throttle valve 13, and proportional-integral-differential control (PID) is performed.
Control) to drive the DC motor 21.

When the throttle control routine is started, first, at step 300, the throttle opening instruction amount TTH by the operation lever 5 is detected. Then step 302
Then, based on the actual throttle opening THR detected by the opening sensor 24, the throttle deviation ΔTTH = TTH
-Calculate THR (= TTH _(t) ).

Next, the routine proceeds to step 304, where the present throttle deviation TTH _(t) and the throttle deviation in the previous process are used as the basis for calculating the component constituted by the differential control of the opening instruction signal supplied to the DC motor 21. TT
By calculating the difference from H _(t-1) , a differential amount DTTH of the throttle deviation is calculated (step 304).

Further, in step 306, as a basis for calculating a component constituted by the integral control in the opening degree instruction signal, the current throttle deviation TTH _(t) is added to the integrated value of the throttle deviation up to the previous time, and ΔTTH integration amount∫
Calculate ΔTTH.

Then, the flow advances to step 308 to set in advance.
Proportional gain G_P, Integral gain G _I, Differential gain G_D
Is used to calculate the basic control amount TTHI as in the following equation.

TTHI = G_P・ ΔTTH + G_I・ ∫ΔT
TH + G_DIf the basic control amount TTHI has been calculated, go to step 310.
Advance, battery voltage V _BIs corrected. car
The voltage of the batteries mounted on both sides depends on the operating conditions of the vehicle, etc.
While it fluctuates much more, the opening of the throttle valve 13
Is required to be controlled with very high accuracy.
It should be noted that the control ECU 1 of the device of the present embodiment_B
Correction coefficient K for_VBIs provided as a map in advance.
(Refer to FIG. 12)._BReferenced by
Correction coefficient K required_VBIs calculated.

Then, the actual control amount is calculated by multiplying the basic control amount TTHI calculated in step 308 by the correction coefficient K _VB, and the value is stored as TTHI (step 312).

After calculating the control amount TTHI to be supplied to the DC motor 21 in this way, in step 314, the duty ratio for realizing the control amount TTHI is calculated. Then, the signal of the duty ratio calculated in step 316 is output to the DC motor drive circuit, and the current process ends.

As described above, in the present embodiment, the opening of the throttle valve 13 is executed by PID control. Therefore, a desired throttle opening can be ensured with high accuracy with good responsiveness to a driver's instruction.

Thus, the processing of step 106 in the main routine shown in FIG. 4 is completed. Thereafter, steps 102 to 106 in the main routine are repeatedly executed unless the disabled mode is canceled, and the vehicle exerts the driving force and the braking force as the driver operates the operation lever 5.

Note that step 1 in FIG.
Step 02 and Step 104 correspond to the drive gain calculating means M50 described above.

According to the above embodiment, the drive gain of the brake operating member 32 is calculated based on the engine speed and the throttle opening, and the EAC is calculated based on the calculated value.
Adjust the opening areas of V1 to V3 as appropriate to
2, the predetermined braking force corresponding to the driver's operational feeling can be obtained irrespective of the fluctuation of the intake negative pressure.

The opening of the throttle valve 13 is determined by PI
Since the D control is performed, a desired throttle opening can be ensured with high accuracy with good responsiveness to a driver's instruction.

Therefore, according to the present embodiment, a predetermined braking force corresponding to the driver's operational feeling can be obtained with good stability, so that the operability of the vehicle and the safety can be improved. As a result, vehicle operation by a physically handicapped person, who conventionally had difficulty in brake operation and the like, becomes easier or possible.

Next, a second embodiment of the present invention will be described.

The hardware configuration of the present embodiment is the same as the hardware configuration of the first embodiment shown in FIG. 2, and a description thereof will be omitted. This embodiment differs from the first embodiment in the brake control executed in step 102 of the main routine shown in FIG.

FIGS. 13 and 14 show a flowchart of a subroutine of the brake control executed in the above step 102. The same processes as those in FIG. 5 are denoted by the same reference numerals and the description thereof will be omitted.

In the brake control subroutine of this embodiment, the gain is corrected in steps 240 to 242 shown in FIG.
48 is used to correct the leakage. This gain correction is a process for further improving the responsiveness, and the leak correction is performed when the required brake pressure is 0, the air in the variable pressure chamber rises due to air leakage from piping or the like, and the leakage pressure is reduced to the negative pressure chamber. This is a process for preventing a braking force from being generated due to the differential pressure of the above, and a process for sufficiently opening the negative pressure introduction valve EACV3 when a small hydraulic pressure is generated when the required brake pressure is zero. The processing in each of the above steps will be described below.

In step 240, the correction gain G _KB1 when the difference ΔBP between the required brake pressure TBPL detected in step 212 and the actual brake pressure BPR is larger than a predetermined value.
It is noted that the correction gain G _KB1 is a value determined as a function of ΔBP, and the control ECU 1
In FIG. 15, a map representing the relationship between G _KB1 and ΔBP shown in FIG. 15 is stored, and G _KB1 can be _obtained by referring to this map with _ΔBP .

After the correction gain G _KB1 is calculated in this way, a new total correction gain G _BRK is obtained in step 242 by multiplying the total correction gain G _BRK obtained in step 220 by the correction gain G _KB1 .

Next, at step 244, it is determined whether or not the required brake pressure TBPL is zero. And TBP
If L = 0, in step 246, ΔBP is 0 <ΔBP ≦
It is determined whether it is KDBP2. Where KDBP2
Is a micro hydraulic pressure. If 0 <ΔBP ≦ KDBP2, in step 248, the value of the total correction gain G _BRK obtained in step 220 or step 242 is set as the value of the control gain G _KB2 . Here, the control gain G _KB2 is
It takes a certain value only when the required brake pressure TBPL is 0,
When TBPL is not 0, the value is larger than the pressure reduction control gain. After the processing of step 248 is completed, step 2
Steps 22 to 228 are sequentially performed. On the other hand, if it is determined in step 244 that TBPL is not 0, or if it is determined in step 246 that 0 <ΔBP ≦ KDBP2, the process proceeds to step 222 and the processes of steps 222 to 228 are sequentially performed.

According to the second embodiment described above, the following effects can be obtained in addition to the effects obtained in the first embodiment.

That is, in steps 240 to 242, since the gain is corrected so that the response of the hydraulic pressure (braking force) can be improved and the hunting can be prevented, the controllability of the braking force can be further improved. In addition to this, a more faithful braking force can be realized according to the driver's intention. Therefore, the drivability and safety of the vehicle can be further improved.

Further, since the leakage correction is performed in steps 244 to 248, it is possible to prevent an erroneous occurrence of a braking force due to a minute pressure change in the variable pressure chamber 31b due to an air leak from a pipe or the like. Since unnecessary braking force is not generated during traveling of the vehicle, it is possible to prevent adverse effects on the durability of the brake system.

Next, a third embodiment of the present invention will be described.

The hardware configuration of the present embodiment is the same as the hardware configuration of the first embodiment shown in FIG. 2, and a description thereof will be omitted. This embodiment differs from the first embodiment in the throttle control executed in step 104 of the main routine shown in FIG. FIGS. 16 and 17 show a flowchart of a subroutine of the throttle control executed in the above step 104. The same processes as those in FIG. 11 are denoted by the same reference numerals and description thereof is omitted.

In the throttle control subroutine according to the present embodiment, in steps 340 to 348 shown in FIG. 17, the responsiveness of the braking force at the time of sudden braking by the sudden operation of the operation lever 5 is further improved, and the maximum value of the braking force generation Is set to a sufficiently large value. The processing in each of the above steps will be described below.

At step 340, it is determined whether or not the throttle opening instruction amount TTH detected at step 300 is zero. If TTH = 0, it is determined in step 342 whether or not there is a brake instruction. When there is a brake instruction, the throttle deviation ΔT is determined in step 344.
It is determined whether or not TH is less than a predetermined set value -KTTM. If .DELTA.TTH <-KTTM, that is, if the throttle valve 13 is still open due to a response delay, the electromagnetic clutch 22 is turned off in step 346, the throttle valve 13 is fully closed, and further in step 348, in step 312. The stored actual control amount TTH
Let I be 0. After the process of step 348 is completed, the processes of steps 314 to 316 are sequentially executed.

On the other hand, when it is determined in step 340 that TTH is not 0, when it is determined in step 342 that there is no brake instruction, or in step 344, ΔTT
When it is determined that H <-KTTH is not satisfied, the process proceeds to step 314, and the processes of steps 314 to 316 are sequentially performed.

According to the third embodiment described above, the following effects can be obtained in addition to the effects obtained in the first embodiment.

That is, when the throttle valve 13 is still in the open state due to a response delay at the time of sudden braking due to the sudden operation of the operation lever 5, the electromagnetic clutch 22 is turned off and the throttle valve 13 is fully closed. Since the engine slows down the engine speed behind the operation of the throttle valve 13, the state where the engine is temporarily high and the throttle valve 13 is fully closed is established, so that the intake negative pressure is sufficiently reduced. Accordingly, since the control B / B 31 holds the intake negative pressure, the responsiveness of the brake hydraulic pressure (braking force) and the maximum value of the generated brake hydraulic pressure become sufficiently large values. Therefore, the safety at the time of sudden braking can be further improved.

[0090]

According to the first aspect of the present invention, it is possible to respond to the vehicle speed.
Since Flip was controlling the braking force by driving a brake operating member based on the drive gain, the Jo Tokoro braking force can be obtained with stability. Further, according to the second aspect of the present invention,
Engine speed and throttle opening along with vehicle speed.
Based on the drive gain corresponding to at least one of
Since the braking force is controlled by driving the brake operating member,
A predetermined braking force can be obtained with higher stability.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is an overall configuration diagram of an example of a braking force control device according to an embodiment of the present invention.

FIG. 3 is a vertical sectional view of an example of a control brake booster according to the embodiment of the present invention.

FIG. 4 is a flowchart of a main routine executed by a control ECU of the apparatus of the embodiment.

FIG. 5 is a flowchart of a brake control subroutine executed by an ECU of the embodiment.

FIG. 6 is a characteristic diagram illustrating a relationship between a throttle opening degree THR and an engine speed NE of the internal combustion engine including the apparatus according to the embodiment, and intake negative pressure E / GB.

7 is a map for determining the correction gain G _B relative to the intake negative pressure E / GB in this example device.

FIG. 8 is a map for _obtaining a correction gain G _VW with respect to a vehicle speed V _W in the embodiment.

FIG. 9 shows a pressure-increase correction gain G _BPU and a pressure-decrease correction gain G with respect to the actual brake pressure BPR in the present embodiment.
_This is a map for _{obtaining BPD} .

FIG. 10 shows the opening area TAF and the current I of the flow rate instruction signal when the air introduction valve and the negative pressure introduction valve of the present embodiment are opened.
It is a characteristic view showing the relationship with.

FIG. 11 is a flowchart of a subroutine of throttle control executed by a control ECU of the present embodiment.

FIG. 12 is a map showing a relationship between a battery voltage used for throttle control and a correction value in the present embodiment device.

FIG. 13 is a flowchart (part 1) of another subroutine of the brake control executed by the control ECU of the apparatus of the embodiment.
It is.

FIG. 14 is a flowchart (part 2) of another subroutine of the brake control executed by the control ECU of the apparatus of the embodiment.
It is.

FIG. 15 shows a brake differential pressure ΔBP
6 is a map for _obtaining a correction gain G _BRK for.

FIG. 16 is a flowchart (part 1) of another subroutine of throttle control executed by the control ECU of the present embodiment.

FIG. 17 is a flowchart (part 2) of another subroutine of throttle control executed by the control ECU of the apparatus of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 control ECU 2 mode changeover switch 5 operating lever 6-9 brake mechanism 10, 11 oil pressure sensor 30 electronic control brake system 31 control brake booster 31a negative pressure chamber 31b variable pressure chamber 31c master cylinder 32, M20 brake operating member EACV1, atmosphere Introducing valve EACV3 Negative pressure introducing valve M10 Negative pressure supply source M30 Engine speed detecting means M40 Throttle opening detecting means M50 Drive gain calculating means

Claims (2)

(57) [Claims] 1. A braking force control device for driving a brake operating member by a negative pressure supplied from a negative pressure supply source to generate a brake fluid pressure and controlling a braking force by the brake fluid pressure, wherein a vehicle speed is detected. Vehicle speed detection means, based on a detection value detected by the vehicle speed detection means ,
And a drive gain calculating means for calculating a drive gain of the brake operation member so that the lower the vehicle speed, the smaller the drive speed . 2. The braking force control device according to claim 1, further comprising: engine speed detecting means for detecting a rotation speed of the internal combustion engine; and throttle opening detecting means for detecting an opening of a throttle valve. The drive gain calculating means detects by the vehicle speed detecting means.
Based on the detected value, the detected value detected by the engine speed detecting means , and the detected value detected by the throttle opening detecting means, the lower the vehicle speed, the smaller the detected value.
So as, as smaller the larger the rotational speed of the internal combustion engine, and the braking force control device, and calculates the driving gain of said brake operating member so as opening of the throttle valve is small small .