JP4779231B2 - Brake control device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a braking control device for a vehicle, and more particularly to a braking control device that controls an automatic hydraulic pressure generating device regardless of operation of a brake pedal and supplies brake hydraulic pressure to a wheel cylinder.
[0002]
[Prior art]
Recently, the use of a braking control device that applies a braking force to a vehicle regardless of the operation of the brake pedal has attracted attention. For example, when traveling in a traffic jam, even a vehicle equipped with an automatic transmission needs to operate an accelerator pedal and a brake pedal alternately, which is complicated. In order to avoid this, it has been proposed that a brake lever is disposed in the vicinity of the steering and is manually operated. As a result, braking force can be applied to the vehicle without operating the brake pedal. Furthermore, if creep is used in a vehicle equipped with an automatic transmission, repeated running and stopping during traffic jams can be performed only by operating the brake lever. It can correspond to. Alternatively, it is possible to measure the inter-vehicle distance with a vehicle ahead by a radar and automatically apply a braking force when the inter-vehicle distance becomes less than a predetermined distance.
[0003]
For example, Japanese Patent Application Laid-Open No. 61-191462 proposes a vehicle brake device that can change the braking force according to the strength of the operation force of the manual switch. In this publication, it is proposed to adjust the braking force by changing the air pressure in the control chamber of the vacuum booster based on the detection result of the manual switch.
[0004]
[Problems to be solved by the invention]
However, in the conventional braking control device including the device described in the above publication, when the automatic hydraulic pressure generating device is driven in accordance with a predetermined condition by the drive signal of the input device, as shown in FIG. Since the presence of hysteresis is unavoidable, a desired wheel cylinder hydraulic pressure cannot be applied unless the automatic hydraulic pressure generator is controlled in consideration of this, and there is a possibility that the desired control cannot be performed. For example, as an input device, a device including a brake lever (manual brake operation member) corresponds to the above-mentioned publication, but exhibits hysteresis characteristics as shown in FIG. 7 when the manual brake operation member is operated and released. Become.
[0005]
Therefore, the present invention provides a vehicle brake control device that controls an automatic hydraulic pressure generating device in accordance with a drive signal of an input device and supplies brake hydraulic pressure to a wheel cylinder. It is an object of the present invention to provide a braking control device that appropriately applies a braking force in consideration of hysteresis when the generator is driven.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a wheel cylinder mounted on each wheel of a vehicle and an automatic hydraulic pressure generator that generates a brake hydraulic pressure regardless of the operation of a brake pedal. An input device for supplying a drive signal for driving the automatic hydraulic pressure generator according to a predetermined condition; and controlling the automatic hydraulic pressure generator according to the drive signal of the input device to brake the wheel cylinder In the vehicle braking control device comprising a control means for supplying hydraulic pressure, the input device includes a manual brake operation member provided independently of the brake pedal, and according to an operation amount of the manual brake operation member configured to output a drive signal, the manual operation speed of the brake operating member is calculated, when the state the manipulation speed is a positive value has continued for a predetermined time or more, the automatic solution Determines that it should a pressurized state in which the brake fluid pressure is supplied from the generator to the wheel cylinder, when the state the operation speed is a negative value is continued for a predetermined time or more, the brake fluid pressure from said wheel cylinder comprising a determining means and should be decompressed state to be released, it said control means is configured to control the pressurized state and a depressurized state by the automatic hydraulic pressure generator based on the determination that said determining means Is. In addition, said decompression state means the state of a decompression direction, and is also called "extraction". The operation speed can be obtained by differentiating the operation amount of the manual brake operation member.
[0008]
Further, according to a second aspect of the present invention, the automatic hydraulic pressure generator drives and controls a vacuum booster that operates at least according to the operation of the brake pedal and a linear solenoid according to the operation of the manual brake operation member. And a booster driving device for driving the vacuum booster, and the control means may be configured to control the booster driving device based on a determination result of the determination means.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 shows an outline of a braking control apparatus according to an embodiment of the present invention. A master cylinder MC is boosted via a vacuum booster VB in accordance with an operation of a brake pedal BP, and the inside of a master reservoir RS is shown. The brake fluid is pressurized and the master cylinder fluid pressure is output to the wheel cylinder WC of each wheel (represented by WL representatively). In this embodiment, a manual brake lever LV, which is a manual brake operation member, is provided in the vicinity of a steering handle (not shown) as the input device IN, and a vacuum booster according to the operation of the manual brake lever LV as will be described later. VB is configured to be driven. The vacuum booster VB will be described later with reference to FIG.
[0010]
In the present embodiment, the brake switch BS that can be turned on when the brake pedal BP is operated and can detect that the brake pedal BP has been operated, and the accelerator sensor that can detect the accelerator opening degree of the accelerator pedal AP. An AS, a sensor LS for detecting the operation amount of the manual brake lever LV, a wheel speed sensor WS for detecting the wheel speed of each wheel WL, and the like are provided. The electronic control unit ECU constituting the control unit and the determination unit of the present invention is not shown, but includes a microcomputer comprising a processing unit, a memory ROM, a RAM, an input port, an output port, and the like connected to each other via a bus. It has. And it is comprised so that the output signal of each said sensor may be input into a processing unit from an input port via an amplifier circuit, respectively. In addition, a control signal is output from the output port via a drive circuit.
[0011]
In the electronic control unit ECU, a program for various processing including the flowcharts shown in FIGS. 3 to 5 is stored in the memory ROM, and the processing unit stores the program while an ignition switch (not shown) is closed. The variable data necessary for executing the program is temporarily stored in the memory RAM. It should be noted that a plurality of microcomputers may be configured for each control such as throttle control or a combination of related controls as appropriate, and electrically connected to each other.
[0012]
Next, the vacuum booster VB is configured as shown in FIG. 2, and at least a booster driving device BD for automatically driving the vacuum booster VB when the brake pedal is not operated is provided. The basic configuration of the vacuum booster VB is the same as that of the prior art. A constant pressure chamber B2 and a variable pressure chamber B3 are formed by the movable wall B1, and the movable wall B1 is integrally connected to the power piston B4. The constant pressure chamber B2 is always connected to an intake pipe (shown by EG in FIG. 1) of the engine so that a negative pressure is introduced. The power piston B4 is connected to an output rod B10 via a fixed core D2 and a reaction disk B9, which will be described later, and the output rod B10 is connected to a master cylinder MC (FIG. 1).
[0013]
In the power piston B4, there is provided a valve mechanism B5 including a vacuum valve V1 for intermittently communicating between the constant pressure chamber B2 and the variable pressure chamber B3, and an air valve V2 for intermittently communicating between the variable pressure chamber B3 and the atmosphere. It has been. The vacuum valve V1 includes an annular valve seat V11 formed on the power piston B4 and an elastic valve body V12 that can be attached to and detached from the annular valve seat V11. The air valve V2 includes an elastic valve seat V21 attached to the elastic valve body V12, and a valve body V22 that can be attached to and detached from the elastic valve seat V21. The valve body V22 is connected to an input rod B6 that can be interlocked with the brake pedal BP, and is urged in a direction to be seated on the elastic valve seat V21 by the urging force of the spring B7. Further, the elastic valve body V12 of the vacuum valve V1 is urged in the direction of seating on the annular valve seat V11 and the elastic valve seat V21 of the air valve V2 is applied in the direction of seating on the valve body V22 by the urging force of the spring B8. It is energized.
[0014]
Thus, the vacuum valve V1 and the air valve V2 of the valve mechanism B5 are opened and closed according to the operation of the brake pedal BP (FIG. 1), and according to the operating force of the brake pedal BP between the constant pressure chamber B2 and the variable pressure chamber B3. As a result, a differential pressure is generated, and an output amplified in accordance with the operation of the brake pedal BP is transmitted to the master cylinder MC.
[0015]
The booster driving device BD has a linear solenoid D1, a fixed core D2, and a movable core D3. The linear solenoid D1 sucks the movable core D3 toward the fixed core D2 when energized. The electronic control unit ECU shown in FIG. Is electrically connected. The fixed core D2 is disposed between the power piston B4 and the reaction disk B9, and can transmit force from the power piston B4 to the reaction disk B9. The movable core D3 is disposed so as to face the fixed core D2 in the linear solenoid D1, and a magnetic gap D4 is formed between the movable core D3 and the fixed core D2. The movable core D3 is engaged with the valve body V22 of the air valve V2, and when the movable core D3 moves relative to the fixed core D2 in the direction of decreasing the magnetic gap D4, the valve body V22 of the air valve V2 moves integrally. Is configured to do. The booster drive device BD is configured to be able to switch between a drive position where the variable pressure chamber B3 communicates with the atmosphere and a release position where the drive position is released regardless of the operation of the brake pedal BP. In the release position, the vacuum booster VB is driven by the valve mechanism B5 according to the brake pedal operation.
[0016]
The input rod B6 includes a first input rod B61 and a second input rod B62. The first input rod B61 is integrally connected to the brake pedal BP. The second input rod B62 can move relative to the first input rod B61, and can be configured to transmit force to the output rod B10 side via the key member B11 by the power piston B4. Therefore, when only the second input rod B62 is driven forward, the first input rod B61 is left behind, and a so-called pedal remaining mechanism is constituted by these first and second input rods B61 and B62.
[0017]
Thus, the vacuum booster VB, the booster driving device BD, and the master cylinder MC constitute an automatic hydraulic pressure generator, and the automatic hydraulic pressure generator is controlled in accordance with the operation of the manual brake lever LV. Automatic pressurization control can be performed without operating the pedal BP, and braking force can be applied to the vehicle. Further, by controlling the automatic hydraulic pressure generator according to the driving state of the vehicle, automatic pressurization control (for example, traction control and braking steering control) can be performed on the wheel to be controlled. Hereinafter, the operation of the vacuum booster VB and the like in these controls will be described.
[0018]
When the automatic pressurization control is started by the electronic control unit ECU, the linear solenoid D1 is energized, the movable core D3 moves to the magnetic gap D4 side, and the valve body V22 of the air valve V2 resists the biasing force of the spring B7. It moves integrally with the movable core D3. As a result, the elastic valve body V12 of the vacuum valve V1 is seated on the annular valve seat V11 by the spring B8, and the communication state between the variable pressure chamber B3 and the constant pressure chamber B2 is blocked. Thereafter, since the valve body V22 of the air valve V2 further moves, the valve body V22 is detached from the elastic valve seat V21, and the atmosphere is introduced into the variable pressure chamber B3. As a result, a differential pressure is generated between the variable pressure chamber B3 and the constant pressure chamber B2, and the power piston B4, the fixed core D2, the reaction disk B9, and the output rod B10 move forward to the master cylinder MC (FIG. 1) side. The brake fluid pressure is automatically output from the cylinder MC.
[0019]
Then, after the power piston B4 is engaged with the key member B11, the second input rod B62 engaged with the key member B11 advances integrally with the power piston B4. At this time, since the forward force of the power piston B4 is not transmitted to the first input rod B61, the initial position is maintained. That is, while the vacuum booster VB is automatically driven by the booster driving device BD, the brake pedal BP is maintained at the initial position.
[0020]
FIG. 3 shows processing when various automatic pressurization controls are performed, including the case where the vacuum booster VB is controlled in accordance with the operation of the manual brake lever LV (hereinafter referred to as manual brake control). When it is closed, it is executed at a predetermined calculation cycle (for example, 6 ms). In FIG. 3, first, in step 101, the microcomputer CMP is initialized, and various calculation values are cleared. Next, at step 102, the wheel speed of each wheel WL (represented by Vw as a representative) is calculated based on the detection signal of the wheel speed sensor WS. Based on the wheel speed Vw of each wheel WL, an estimated vehicle body speed Vso is calculated in step 103 according to, for example, MIN [Vw] (where MIN is a function for obtaining a minimum value).
[0021]
Subsequently, the routine proceeds to step 104, where it is determined whether or not manual brake control can be performed, that is, permission determination is performed. Further, in step 105, manual brake control start / end determination is performed (see FIG. 4). And will be described later with reference to FIG. 5). Next, proceeding to step 106, the target current of the booster solenoid is set. Then, the process proceeds to step 107, and a booster solenoid signal is output based on the target current set in step 106.
[0022]
FIG. 4 shows the manual brake control permission determination process executed in step 104 of FIG. 3. First, in step 201, the operation state of the brake pedal BP is determined. If the brake pedal BP is not operated and the brake switch BS is turned off, the routine proceeds to step 202, where it is determined whether or not the accelerator pedal AP is operated by the accelerator sensor AS. If it is determined in step 202 that the accelerator pedal AP is not operated, the routine proceeds to step 203, where it is determined whether or not the manual brake lever LV is operated. If the manual brake lever LV has been operated, a control flag Fb permitting manual brake control is set (1) in step 204. Accordingly, when the brake pedal BP is operated, when the accelerator pedal AP is operated, and when the manual brake lever LV is not operated, the control flag Fb is reset (0) in step 205, and the manual brake control is performed. I can't.
[0023]
FIG. 5 shows a process for determining the start / end of manual brake control executed in step 105 of FIG. 3, and will be described with reference to the time chart of FIG. First, in step 301, the state of the control flag Fb is determined. If the control flag Fb is not set, the process directly returns to the main routine, but if it is set, the process proceeds to step 302 to determine the operating state of the manual brake lever LV. The For example, when the operation amount of the manual brake lever LV changes as shown in the uppermost stage of FIG. 6, when the operation speed is obtained, it changes as shown in the second stage of FIG. After the hour, the amount of change is positive, and between t1 and t3 and after t5, the amount of change is negative.
[0024]
Thus, when it is determined in step 302 that the operation speed of the manual brake lever LV is a positive value, the process proceeds to step 303 where the value ta (time) of the pressurization determination counter is compared with a predetermined value Kt (time). The Since the value ta of the pressure determination counter is 0 at the first time, the process proceeds to step 306 and ta is incremented (ta ← ta + 1). When it is determined that the pressure determination counter value ta is equal to or greater than the predetermined value Kt, the pressure decrease determination counter value tb is cleared (0) in step 304, and then the process proceeds to step 305 where the pressure flag is set ( 1) and the decompression flag is reset (0). For example, when the operating speed of the manual brake lever LV becomes a positive value at t3 in FIG. 6, the pressurization determination counter (ta) starts counting, and at t4 when the predetermined value Kt is reached, the depressurization determination counter (tb) Cleared (0), the determination flag is set to “pressurization” (that is, the pressurization flag is set and the pressure reduction flag is reset in FIG. 5 ).
[0025]
On the other hand, if it is determined in step 302 in FIG. 5 that the operating speed of the manual brake lever LV is a negative value, the process proceeds to step 307, where the value tb (time) of the pressure reduction determination counter is compared with a predetermined value Kt (time). The Since the value tb of the decompression determination counter is 0 at the first time, the process proceeds to step 310, where tb is incremented (tb ← tb + 1). When it is determined that the value tb of the depressurization determination counter is equal to or greater than the predetermined value Kt, after the value ta of the pressurization determination counter is cleared (0) in step 308, the process proceeds to step 309 and the depressurization flag is set (1 ) And the pressurization flag is reset (0). For example, when the operation speed of the manual brake lever LV becomes a negative value at t1 (and t5) in FIG. 6, the pressure reduction determination counter (tb) starts counting, and at t2 when the predetermined value Kt is reached (and t6). ), The pressurization determination counter (ta) is cleared (0), and the determination flag is set to “depressurization” (that is, the depressurization flag is set and the pressurization flag is reset in FIG. 5 ). Note that “reduced pressure” at this time is also referred to as “removal” and means an operation in the reduced pressure direction.
[0026]
Based on the pressure flag or the pressure reduction flag set as described above, the target current of the booster solenoid D1 (FIG. 2) is set in step 106 of FIG. 3, and the booster solenoid signal is output based on this target current (step). 107). Accordingly, a pressurization request or a depressurization request is appropriately made according to the operation of the manual brake lever LV, and the booster solenoid D1 is driven and the vacuum booster VB is driven accordingly, so that the manual brake lever LV is operated. Even when the hysteresis characteristic is exhibited, it is possible to appropriately drive the vacuum booster VB and apply the desired braking force.
[0027]
As described above, in the present embodiment, the vacuum booster VB is configured to be driven in accordance with the operation of the manual brake lever LV (manual brake operation member). There are various modes without being limited thereto. For example, there are devices including various sensors in an inter-vehicle distance maintenance system using radar-detected automatic brakes and an automatic stop system using automatic brakes when collecting tolls. The same applies to braking control devices equipped with these sensors. it can.
[0028]
In the above embodiment, the automatic hydraulic pressure generating device is configured by the vacuum booster VB, the booster driving device BD, and the master cylinder MC. For example, the automatic hydraulic pressure generating device is sucked from the master reservoir RS or the master cylinder MC by a hydraulic pump. The brake fluid whose pressure has been increased may be supplied to the wheel cylinder.
[0029]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle brake control device according to claim 1, when the operation speed of the manual brake operation member is a positive value continues for a predetermined time or more , the brake fluid pressure is applied from the automatic hydraulic pressure generator to the wheel cylinder. Is determined to be in a pressurized state in which the brake fluid pressure is supplied, and when the state in which the operation speed is a negative value continues for a predetermined time or longer , it is determined that a reduced pressure state in which the brake fluid pressure is released from the wheel cylinder is determined. Based on the determination result, the pressure state and the pressure-reducing state by the automatic hydraulic pressure generator are controlled manually . Therefore , the influence of the hysteresis of the brake hydraulic pressure by the automatic hydraulic pressure generator on the operation of the manual brake operation member is affected. It is possible to reduce and apply an appropriate braking force according to the operation of the manual brake operation member.
[0031]
Furthermore, in the braking control device according to claim 2 , since it is applied to an automatic hydraulic pressure generator provided with a vacuum booster and a booster drive device, the booster drive device is appropriately applied according to the operation of the manual brake operation member. The desired braking force can be applied.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a vehicle braking control apparatus according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a vacuum booster used in an embodiment of the present invention.
FIG. 3 is a flowchart showing a manual brake control process in an embodiment of the present invention.
4 is a flowchart showing a process for determining whether to permit manual brake control in FIG. 3;
FIG. 5 is a flowchart showing processing for determining start / end of manual brake control in FIG. 3;
FIG. 6 is a time chart showing a determination state of a pressurization state and a decompression state during manual brake control in one embodiment of the present invention.
FIG. 7 is a graph showing an example of input / output characteristics in conventional automatic pressurization control.
[Explanation of symbols]
BP brake pedal, BS brake switch,
AP accelerator pedal, AS accelerator sensor,
VB vacuum booster, BD booster drive,
MC master cylinder, RS master reservoir,
IN input device, LV manual brake lever,
ECU electronic control unit, WC wheel cylinder, WL wheel

Claims (2)

A wheel cylinder mounted on each wheel of the vehicle, an automatic hydraulic pressure generator that generates brake hydraulic pressure regardless of the operation of the brake pedal, and a drive signal for driving the automatic hydraulic pressure generator according to a predetermined condition In the vehicle braking control device comprising: an input device to be supplied; and a control unit that controls the automatic hydraulic pressure generator in accordance with a drive signal of the input device and supplies brake hydraulic pressure to the wheel cylinder. The apparatus includes a manual brake operation member provided independently of the brake pedal, and is configured to output a drive signal corresponding to an operation amount of the manual brake operation member, and calculates an operation speed of the manual brake operation member. and, when the state the manipulation speed is a positive value has continued for a predetermined time or more, the brake fluid pressure is supplied to the wheel cylinder from said automatic hydraulic pressure generator Determines that it should a pressurized state, when the state the operation speed is a negative value is continued for a predetermined time or more, the determination means and should be depressurized brake fluid pressure from the wheel cylinders is released A braking control apparatus for a vehicle, wherein the control means controls the pressurization state and the pressure reduction state by the automatic hydraulic pressure generation device based on a determination result of the determination means. The automatic hydraulic pressure generator includes at least a vacuum booster that operates according to an operation of the brake pedal, and a booster drive device that drives and controls a linear solenoid according to an operation of the manual brake operation member. wherein the control means, the braking control device for a vehicle according to claim 1, wherein the controller controls the booster actuator based on the determination result of said determining means.

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