JP2022182559A - Brake control device of vehicle - Google Patents

Abstract

To provide a brake control device which may surely maintain the vehicle stop state.SOLUTION: A brake control device comprises: an actuator (HU) which electrically adjusts brake fluid pressure (Pw) of a wheel cylinder (CW) of a vehicle (JV); and a controller (ECU) which controls the actuator (HU) on the basis of an operation amount (Ba) of a brake operation member (BP) of the vehicle (JV). The controller (ECU) is configured to perform raising of increasing the brake fluid pressure (Pw) by prescribed fluid pressure (Pk) at a time point (t3) for determining the stop state of the vehicle (JV). Further, the controller (ECU) continues the raising even when the vehicle (JV) starts to move in a case where the operation amount (Ba) is larger than a prescribed amount (bx).SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a vehicle braking control device.

In Patent Document 1, for the purpose of "executing control to maintain the braking force of the vehicle by a simple operation by the intention of the passenger," a brake is applied to the wheels by a predetermined braking device that operates based on the braking operation of the passenger. In a braking control device for a vehicle that controls applied braking force, vehicle speed detection means for detecting the vehicle speed of the vehicle (step S101) and braking operation detection means for detecting the amount of braking operation by the passenger in the predetermined braking device Steps S102 to S105), and when the vehicle speed detecting means detects that the vehicle speed has become equal to or lower than a predetermined vehicle speed, the braking operation detecting means detects a first braking operation amount of the occupant in the predetermined braking device. is detected, and then a braking force holding means (step S103 to S106) and” is described. Specifically, in the braking control device described in Patent Document 1, after the first braking operation amount is detected, the first braking operation amount is larger than a value obtained by adding a predetermined amount to the first braking operation amount. 2 is detected, the braking force is maintained.

By the way, on an inclined road surface (for example, an uphill road or a downhill road), the vehicle may be stopped (that is, stopped) in a state where the force caused by the gravitational acceleration component of the vehicle and the braking force are substantially equal. In this situation, even a slight decrease in braking force may cause the vehicle to start moving, causing the driver to feel uncomfortable. Similarly, when the vehicle is stopped in a state where the creep torque and the braking force are substantially equal, a phenomenon similar to that occurring on an uphill road or the like may occur. A braking control device for a vehicle is desired to be capable of reliably maintaining a stopped state.

JP 2006-213287 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a braking control device for a vehicle that can reliably maintain a stopped state.

A braking control device for a vehicle according to the present invention comprises an actuator (HU) for electrically adjusting brake fluid pressure (Pw) of a wheel cylinder (CW) of a vehicle (JV), and a braking operation member ( a controller (ECU) that controls the actuator (HU) based on the manipulated variable (Ba) of the BP).

In the vehicle braking control device according to the present invention, the controller (ECU) reduces the braking hydraulic pressure (Pw) by a predetermined hydraulic pressure (Pk) at time (t3) when the vehicle (JV) is determined to be stopped. It is configured to provide incremental padding. Further, when the operation amount (Ba) is larger than the predetermined amount (bx), the controller (ECU) continues the raising even if the vehicle (JV) starts moving.

According to the above configuration, when the vehicle JV is stopped, the stopped state is reliably maintained by raising the brake hydraulic pressure Pw. Further, even if the vehicle JV starts to move, since the raising is continued, the vehicle JV can be started smoothly.

1 is a schematic diagram for explaining an entire vehicle equipped with a braking control device SC according to the present invention; FIG. FIG. 4 is a flow chart for explaining pressure regulation control processing; FIG. 4 is a time-series diagram for explaining the operation of pressure regulation control;

Hereinafter, an embodiment of a vehicle braking control device SC according to the present invention will be described with reference to the drawings.

<Symbols of constituent elements, etc.>
In the following description, constituent elements such as members, signals, values, etc. denoted by the same reference numerals such as "CW" have the same function. The suffixes "f" and "r" attached to the end of various symbols related to wheels are generic symbols indicating whether the elements relate to the front wheels or the rear wheels. Specifically, "f" indicates "elements related to front wheels" and "r" indicates "elements related to rear wheels". For example, the wheel cylinders CW are described as "front wheel cylinder CWf, rear wheel cylinder CWr". Additionally, the subscripts "f" and "r" may be omitted. When these are omitted, each symbol represents its generic name.

<Vehicle JV equipped with braking control device SC>
An overall configuration of a vehicle JV equipped with a braking control device SC according to the present invention will be described with reference to the schematic diagram of FIG. The vehicle JV is equipped with a braking operation member BP, a braking device SX, various sensors (such as VW), and a braking control device SC.

The vehicle JV is provided with a braking operation member BP. A braking operation member (for example, a brake pedal) BP is a member operated by the driver to decelerate the vehicle. A braking fluid pressure Pw is generated by a braking control device SC (described later) in accordance with the operation amount Ba of the braking operation member BP. Then, the brake fluid pressure Pw is supplied to the brake device SX.

Each wheel WH of the vehicle JV is provided with a braking device SX so as to generate a braking force Fx on the wheel WH in accordance with the braking fluid pressure Pw. The braking device SX is composed of a rotating member (for example, a brake disc) KT and a brake caliper CP. The rotating member KT is fixed to the wheel WH, and a brake caliper CP is provided so as to sandwich the rotating member KT. A wheel cylinder CW is provided in the brake caliper CP. A braking fluid BF adjusted to a braking fluid pressure Pw is supplied to the wheel cylinder CW from the braking control device SC. The braking fluid pressure Pw presses the friction member (for example, brake pad) MS against the rotating member KT. Since the rotary member KT and the wheels WH are fixed so as to rotate integrally, the braking force Fx is generated on the wheels WH by the frictional force generated at this time.

The vehicle JV is equipped with various sensors such as a braking operation amount sensor BA, a steering amount sensor SA, a wheel speed sensor VW, a yaw rate sensor YR, a longitudinal acceleration sensor GX, and a lateral acceleration sensor GY.

A braking operation amount sensor BA is provided for detecting an operation amount Ba of a braking operation member (brake pedal) BP. Specifically, as the braking operation amount sensor BA, a master cylinder hydraulic pressure sensor PM (not shown) that detects the hydraulic pressure in the master cylinder CM (master cylinder hydraulic pressure), and the operating displacement Sp of the braking operation member BP are detected. At least one of an operation displacement sensor SP (not shown) and an operation force sensor FP (not shown) that detects the operation force Fp of the braking operation member BP is employed. That is, the braking operation amount Ba is determined based on at least one of the master cylinder hydraulic pressure Pm, the braking operation displacement Sp, and the braking operation force Fp.

A steering amount sensor SA (for example, a steering angle sensor) is provided for detecting an operation amount Sa of a steering operation member (for example, a steering wheel) (not shown). The steering operation amount Sa (for example, the steering angle) is the displacement from the steering neutral position "Sa=0" corresponding to straight running of the vehicle. Each wheel WH of the vehicle JV is provided with a wheel speed sensor VW for detecting a wheel speed Vw, which is the rotational speed of the wheel WH. The vehicle JV also includes a yaw rate sensor YR for detecting the actual yaw rate (yaw angular velocity) Yr of the vehicle body, a longitudinal acceleration sensor GX for detecting acceleration (longitudinal acceleration) Gx of the vehicle body in the longitudinal direction, and A lateral acceleration sensor GY for detecting acceleration (lateral acceleration) Gy is provided.

The vehicle JV is equipped with a braking control device SC to supply pressurized braking fluid BF to the braking device SX (particularly the wheel cylinder CW). Specifically, the brake control device SC electrically generates the brake hydraulic pressure Pw in accordance with the operation amount Ba of the brake operation member BP. Then, the braking fluid pressure Pw is supplied to the wheel cylinder CW to generate the braking force Fx on the wheels WH. The braking control device SC is composed of a hydraulic unit HU (also referred to as an "actuator") including a master cylinder CM, and a controller ECU (also simply referred to as a "controller") for the braking control device SC.

A hydraulic unit HU (actuator) electrically generates a braking hydraulic pressure Pw using an electric motor MA as a power source. The braking fluid pressure Pw is supplied to the wheel cylinders CW via the front and rear wheel communication paths HSf and HSr. For example, the braking control device SC employs a so-called front-rear type (also referred to as "II type") as the two braking systems. Also, a so-called diagonal type (also referred to as "X type") type may be employed as the two braking systems. The brake control device SC is provided with a brake fluid pressure sensor PW for detecting the brake fluid pressure Pw.

For example, the fluid unit HU includes a stroke simulator SS (simply referred to as "simulator"). That is, the braking control device SC can employ a so-called brake-by-wire configuration. Specifically, the operating force Fp of the brake operating member BP is generated by the simulator SS. A piston and an elastic body (for example, a compression spring) are provided inside the simulator SS. When the brake fluid BF flows into the simulator SS, the piston is pushed by the brake fluid BF. Since a force is applied to the piston by the elastic body in a direction to prevent the inflow of the brake fluid BF, an operating force Fp of the brake operating member BP is generated. That is, the operating characteristics of the brake operating member BP (the relationship between the operating displacement Sp and the operating force Fp) are formed by the simulator SS.

Since the operating force Fp is generated by the simulator SS, a simulator hydraulic pressure sensor PU (not shown) that detects the hydraulic pressure (simulator hydraulic pressure) Pu in the simulator SS corresponds to the above-described operating force sensor FP. Further, in a configuration in which the simulator SS is connected to the master cylinder CM, the simulator hydraulic pressure sensor PU corresponds to the master hydraulic pressure sensor PM. That is, the simulator hydraulic pressure sensor PU is one of the braking operation amount sensors BA, and the simulator hydraulic pressure Pu is one of the braking operation amount Ba.

<<Configuration example of fluid unit HU>>
For example, as the fluidic unit HU (actuator), the configurations listed below are adopted. In any case, the fluid unit HU can electrically adjust the hydraulic pressure (brake hydraulic pressure) Pw of the wheel cylinder CW using the electric motor as a power source.
- A configuration in which the hydraulic pressure (brake hydraulic pressure) Pw of the wheel cylinder CW is controlled via a linear valve based on the high pressure (accumulator hydraulic pressure) stored in the accumulator using an electric motor as a power source (for example, See JP 2008-006893).
- A configuration in which the braking hydraulic pressure Pw is controlled via the master cylinder based on the accumulator hydraulic pressure (see, for example, Japanese Patent Laid-Open No. 2018-047807).
- A configuration in which the brake fluid BF discharged by a fluid pump driven by an electric motor is throttled by a linear valve to control the brake fluid pressure Pw (see, for example, Japanese Unexamined Patent Application Publication No. 2016-144952).
- A configuration in which a piston inserted in a cylinder is directly driven by an electric motor to adjust the braking fluid pressure Pw (see, for example, JP-A-2015-231821).

The braking control device SC is provided with a controller ECU for controlling the fluid unit HU described above. Signals such as the braking operation amount Ba, the braking fluid pressure Pw, the wheel speed Vw, and the longitudinal acceleration Gx are input to the controller ECU. Based on these signals, the controller ECU controls the electromagnetic valves, the electric motors, and the like that constitute the fluidic unit HU. The controller ECU is composed of "microprocessor MP for signal processing" and "driving circuit DD for driving solenoid valves and electric motors". Note that the controller ECU is connected to other controllers via a communication bus BS so as to share information (detected values, calculated values, etc.) with other systems.

The controller ECU calculates the vehicle body speed Vx of the vehicle JV based on the wheel speed Vw. Further, the controller ECU executes antilock brake control for suppressing locking of the wheels WH based on the wheel speed Vw and the vehicle body speed Vx. Furthermore, the controller ECU maintains the stability of the vehicle JV (that is, suppresses excessive understeer/oversteer behavior) based on the steering operation amount Sa, yaw rate Yr, longitudinal acceleration Gx, lateral acceleration Gy, etc. Vehicle stability control is executed.

<Pressure regulation control process>
An example of pressure regulation control processing in the braking control device SC will be described with reference to the flowchart of FIG. 2 . "Pressure adjustment control" uses the electric motor MA as a power source to electrically generate and adjust the brake fluid pressure Pw. A pressure regulation control algorithm is programmed in the microprocessor MP in the controller ECU.

At step S110, various signals including the braking operation amount Ba, brake fluid pressure Pw, wheel speed Vw, longitudinal acceleration Gx, etc. are read. Here, the braking operation amount Ba (generic name for the operation state amount of the braking operation member BP) is detected by the braking operation amount sensor BA. The brake fluid pressure Pw is detected by a brake fluid pressure sensor PW. Wheel speed Vw is detected by a wheel speed sensor VW. The longitudinal acceleration Gx is detected by a longitudinal acceleration sensor GX.

At step S120, the vehicle body speed Vx is calculated based on the wheel speed Vw and a known method. Also, the vehicle body speed Vx may be obtained from another controller through the communication bus BS.

At step S130, the required hydraulic pressure Ps (variable) is calculated. The requested hydraulic pressure Ps is a target value corresponding to the braking hydraulic pressure Pw (actual value) for decelerating the vehicle JV requested by the driver. The required hydraulic pressure Ps is determined based on the braking operation amount Ba (variable) and the calculation map Zps, as shown in block X130. Specifically, according to the calculation map Zps, the required hydraulic pressure Ps is calculated to be "0" when the braking operation amount Ba is within the range from "0" to the play amount bo. When the braking operation amount Ba is equal to or greater than the play amount bo, the required hydraulic pressure Ps is calculated to increase from "0" as the braking operation amount Ba increases. That is, when "Ba≧bo", the required hydraulic pressure Ps is determined to increase as the braking operation amount Ba increases. Here, the amount of play bo is a predetermined value (constant) set in advance and corresponds to the play of the braking operation member BP.

In step S140, "whether or not the vehicle JV is in a stopped state (referred to as 'stop determination')" is determined based on the vehicle body speed Vx. If the vehicle body speed Vx is greater than "0" and the vehicle JV is still decelerating, the vehicle stop judgment is denied, and the process proceeds to step S150. When the vehicle body speed Vx is "0" and the vehicle JV is stopped, the determination of the vehicle stop is affirmative, and the process proceeds to step S160.

In step S150, deceleration control is executed. The "deceleration control" decelerates the vehicle JV in accordance with the braking operation amount Ba. Specifically, in deceleration control, the required hydraulic pressure Ps required by the braking operation amount Ba is calculated as the target hydraulic pressure Pt (that is, "Pt=Ps"). Here, the target hydraulic pressure Pt is the final target value of the hydraulic pressure to be achieved by the braking control device SC. Therefore, the required hydraulic pressure Ps can be said to be an intermediate target value for calculating the target hydraulic pressure Pt.

In the deceleration control of step S150, the fluid unit HU is controlled so that the braking hydraulic pressure Pw (actual value) approaches and coincides with the target hydraulic pressure Pt (target value). That is, in deceleration control, hydraulic pressure feedback control is executed based on the detected value Pw of the braking hydraulic pressure sensor PW.

In step S160, stop control is executed. The "stop control" maintains the stopped state of the vehicle JV. Specifically, in the stop control, a predetermined hydraulic pressure Pk is further added to the required hydraulic pressure Ps required by the braking operation amount Ba to calculate the target hydraulic pressure Pt, which is the final target value. (ie, "Pt=Ps+Pk"). Here, adding the predetermined hydraulic pressure Pk to the required hydraulic pressure Ps, and as a result, increasing the braking hydraulic pressure Pw by the predetermined hydraulic pressure Pk is called "raising". Further, the predetermined hydraulic pressure Pk is also referred to as "raising hydraulic pressure". In the vehicle stop control, as in the deceleration control, the hydraulic pressure feedback control of the fluid unit HU is performed so that the braking hydraulic pressure Pw approaches and coincides with the target hydraulic pressure Pt.

For example, the predetermined hydraulic pressure Pk (raising hydraulic pressure) is determined as a preset predetermined value (constant). Further, the predetermined hydraulic pressure Pk may be calculated based on the road surface gradient Kv. Specifically, as shown in block X160, the predetermined hydraulic pressure Pk is determined to increase as the road surface gradient Kv increases according to the calculation map Zpk. The road surface gradient Kv is the gradient of the road (for example, the gradient of an uphill road or a downhill road) with respect to the front-rear direction (traveling direction) of the vehicle JV when the vehicle JV stops. The road surface gradient Kv is calculated based on the detected value (longitudinal acceleration) Gx of the longitudinal acceleration sensor GX. Also, the road surface gradient Kv may be acquired from the map information via the communication bus BS or the like. In the calculation map Zpk, a lower limit value pk and an upper limit value pj are provided for the predetermined hydraulic pressure Pk to be calculated. Here, the lower limit value pk and the upper limit value pj are preset predetermined values (constants).

Further, the predetermined hydraulic pressure Pk may be determined so as to gradually decrease as the braking operation member BP is returned toward "0 (initial position corresponding to the non-braking state)". Here, the predetermined hydraulic pressure Pk is provided with a lower limit value pk. Specifically, the predetermined hydraulic pressure Pk is determined when the vehicle JV stops (when the vehicle stops). Then, when the braking operation amount Ba is constant, the predetermined hydraulic pressure Pk at the point of stop of the vehicle is maintained. After that, the predetermined hydraulic pressure Pk is gradually decreased as the braking operation amount Ba is decreased. However, since the predetermined hydraulic pressure Pk is provided with a lower limit value pk, the target hydraulic pressure Pt is higher than the required hydraulic pressure Ps by at least the lower limit value pk even when the stop control is terminated. .

The stop control is continued when the braking operation amount Ba is larger than the predetermined amount bx even if the vehicle JV starts moving. That is, the raising by the stop control is started when it is determined that the vehicle JV has stopped, and is finished when the condition that the braking operation amount Ba is equal to or less than the predetermined amount bx is satisfied. Here, the predetermined amount bx is a threshold value corresponding to the braking operation amount Ba, and is a preset predetermined value (constant) near "0". For example, the predetermined amount bx can be set to '0'. In this case, after the vehicle JV starts to move, the stop control continues to be executed until the brake operation member BP is completely returned to the initial position "0", and the brake fluid pressure Pw is increased. When the braking operation is completely terminated and the braking operation amount Ba is returned to "0", the stop control is terminated and the predetermined hydraulic pressure Pk is reduced to "0" in a stepwise manner. In other words, while the vehicle stop control is being executed, even if the vehicle JV is moving, the braking hydraulic pressure Pw continues to be increased by the predetermined hydraulic pressure Pk (at least by the lower limit value pk) with respect to the required hydraulic pressure Ps.

In the stop control, the brake hydraulic pressure Pw is raised by a predetermined hydraulic pressure Pk as compared with the deceleration control. That is, when the vehicle is stopped, the predetermined hydraulic pressure Pk is added to the braking hydraulic pressure Pw as a margin. Therefore, creep torque and gravity caused by road surface gradients are less likely to affect the stopped state of the vehicle. As a result, the vehicle JV does not start moving against the will of the driver, and can be maintained in a reliable stopped state.

The stop control is continued even after the vehicle JV starts moving, and ends when the braking operation amount Ba becomes equal to or less than the predetermined amount bx. When the vehicle JV begins to move (that is, when the vehicle is no longer in a stopped state), if the raising by the vehicle stop control is immediately terminated, discontinuity will occur in the movement of the vehicle JV (for example, vehicle body acceleration), and the driver will feel discomfort. I can feel it. In order to avoid this situation, the padding by the predetermined hydraulic pressure Pk is terminated when "Ba≤bx" is satisfied. By continuing to raise the brake fluid pressure Pw in this manner, the above discontinuity can be avoided when the vehicle JV is started, and smooth and good start characteristics can be ensured.

<Operation of pressure regulation control>
An operation example of pressure regulation control including vehicle stop control will be described with reference to the time series diagram of FIG. In the example, it is assumed that the vehicle JV running at a constant vehicle speed Vx is decelerated and then stopped. Here, the road surface at the time when the vehicle JV stops is a downhill road with a downward slope. Further, in the termination condition of the stop control, the predetermined amount bx (threshold value related to the braking operation amount Ba) is set to "0".

In the diagram, the period from time t0 (start of braking operation) to time t3 (stop determination time) corresponds to the deceleration control in step S150, and the period from time t3 to time t7 (end of braking operation) corresponds to step S160. It corresponds to the stop control of Since the braking hydraulic pressure Pw is controlled to match the target hydraulic pressure Pt, the braking hydraulic pressure Pw and the target hydraulic pressure Pt overlap.

Until time t0, no braking operation is performed, and the vehicle JV is traveling at a constant speed of "Vx=vo". At time t0, the operation of the braking operation member BP is started, and the braking operation amount Ba is increased from "0 (initial position)". Then, at time t1, the braking operation amount Ba is held at the value ba.

From time t0, the required hydraulic pressure Ps is sequentially increased from "0" according to the calculation map Zps. Then, from time t1, the required hydraulic pressure Ps is maintained at the value pa corresponding to "Ba=ba". Since the vehicle JV has not yet stopped, the deceleration control of step S150 is executed. Therefore, the final target value (target hydraulic pressure) Pt is calculated to be equal to the required hydraulic pressure Ps. That is, the target hydraulic pressure Pt is determined based on "Pt=Ps". The braking hydraulic pressure Pw is controlled (increased) by the deceleration control so as to match the target hydraulic pressure Pt. By this deceleration control, deceleration of the vehicle JV is started at time t0, and from time t1, the vehicle body deceleration is constant and the vehicle body speed Vx is decreased corresponding to "Pw=pa".

At time t2, the vehicle body speed Vx becomes "0" and the vehicle JV stops. Immediately after time t2 (that is, time t3), the determination of the vehicle stop in step S140 is affirmative, and the vehicle stop state (that is, the state of "Vx=0") is identified. Along with this, the state flag FT is switched from "0" to "1". Here, the state flag FT is a control flag indicating a stopped state, and "1" indicates a stopped state, and "0" indicates a running state (not a stopped state, but a state where the vehicle JV is moving). do.

At time t3, pressure regulation control is switched from deceleration control (process of step S150) to vehicle stop control (process of step S160). In other words, at time t3, deceleration control is terminated and vehicle stop control is started. Thus, from time t3, the final target value (target hydraulic pressure) Pt is calculated by adding the predetermined hydraulic pressure Pk to the required hydraulic pressure Ps. That is, the target hydraulic pressure Pt is determined based on "Pt=Ps+Pk". In the stop control as well, the braking hydraulic pressure Pw is adjusted so that it approaches and coincides with the target hydraulic pressure Pt. That is, even if the braking operation amount Ba is the same, in the case of stop control, braking hydraulic pressure Pw that is higher by a predetermined hydraulic pressure Pk than in the case of deceleration control is supplied to the wheel cylinder CW.

At time t4, the return operation of the braking operation member BP is started. From time t4, the braking operation amount Ba is gradually decreased toward "0". At time t5, the vehicle JV begins to move due to the gravitational force due to the downward slope and the creep torque generated by the engine of the vehicle JV. Immediately after that, at time t6, the running state of the vehicle JV (that is, "Vx≠0") is identified, and the state flag FT is switched from "1 (stopped state)" to "0 (running state)". However, since the braking operation amount Ba has not been returned to "0 (=bx)", the vehicle stop control is continued.

At time t7 after the vehicle JV starts moving, the braking operation member BP is completely returned to the initial position (non-braking state), and the braking operation amount Ba is set to "0". At time t7, the stop control is terminated, and the predetermined hydraulic pressure Pk is rapidly reduced to "0". At time t7, "Ba=0" and therefore "Ps=0" (see the calculation map Zps). Therefore, at time t7, the target hydraulic pressure Pt is determined to be "0", and the braking hydraulic pressure Pw is adjusted to "0".

The predetermined hydraulic pressure Pk can be calculated so as to decrease as the braking operation amount Ba decreases. However, the predetermined hydraulic pressure Pk is provided with a preset lower limit value pk (constant). In this case, the target hydraulic pressure Pt transitions as indicated by the one-dot chain line (a). Even in the configuration in which the predetermined hydraulic pressure Pk is gradually decreased, the target hydraulic pressure Pt is higher than the required hydraulic pressure Ps by at least the lower limit value pk immediately before the braking operation is terminated. At time t7, the target hydraulic pressure Pt is rapidly reduced to "0".

Since the brake hydraulic pressure Pw is increased by the stop control, the vehicle JV is reliably maintained in a stopped state without being affected by the creep torque of the engine, the road gradient, and the like. Furthermore, the raising of the brake fluid pressure Pw is continued until the braking operation amount Ba becomes equal to or less than the predetermined amount bx (for example, until the braking operation is completely terminated) even if the vehicle JV is moving. Thereby, the vehicle JV is smoothly started without suddenly starting to move. That is, it is avoided that the vehicle JV is started with acceleration greater than that intended by the driver.

In the above example, the braking operation member BP is maintained at a constant value ba while the vehicle is stopped, but the case where the operation amount Ba of the braking operation member BP is increased is illustrated by the chain double-dashed line (b). . At time t4, when the braking operation amount Ba is increased, the required hydraulic pressure Ps is increased in accordance with the increase in the braking operation amount Ba. In accordance with this, the target hydraulic pressure Pt is increased. Even if the pressure is raised by the predetermined hydraulic pressure Pk, the operation amount Ba of the braking operation member BP by the driver is reflected in the pressure regulation control.

<Summary of Embodiment of Braking Control Device SC>
Embodiments of the braking control device SC according to the present invention are summarized below. The brake control unit SC includes an actuator (fluid unit) HU for electrically adjusting the brake fluid pressure Pw of the wheel cylinder CW of the vehicle JV, and a controller ECU for controlling the actuator HU based on the operation amount Ba of the brake operation member BP. and are provided. More specifically, the controller ECU controls the hydraulic unit so that the braking hydraulic pressure Pw (detected value of the braking hydraulic pressure sensor PW) approaches and coincides with the target hydraulic pressure Pt calculated based on the braking operation amount Ba. HU is controlled.

In the braking control device SC, raising is executed at the point in time when the controller ECU determines that the vehicle JV is stopped (at the point of time when the vehicle is determined to be stopped). Here, "increase" means that the braking hydraulic pressure Pw is increased by a predetermined hydraulic pressure Pk. Specifically, when the vehicle JV is running (that is, when it is not determined that the vehicle JV is stopped), the required hydraulic pressure Ps calculated based on the braking operation amount Ba is used as the target hydraulic pressure Pt. determined (ie, "Pt=Ps"). On the other hand, when it is determined that the vehicle JV is stopped, a value obtained by adding the predetermined hydraulic pressure Pk to the required hydraulic pressure Ps is calculated as the target hydraulic pressure Pt (that is, "Pt=Ps+Pk"). ). That is, when the vehicle is determined to be stopped, the brake hydraulic pressure Pw is increased stepwise by a predetermined hydraulic pressure Pk as a margin component for maintaining the stopped state. By raising the level in consideration of the margin component Pk, the vehicle JV is prevented from starting to move unnecessarily due to the creep torque and the road surface gradient, and a reliable stop state is ensured.

When the operation amount Ba is larger than the predetermined amount bx (that is, "Ba>bx"), the controller ECU of the braking control device SC raises (increases by the predetermined hydraulic pressure Pk) even after the vehicle JV starts moving. is continued. That is, the raising by the stop control continues from the time when the stop is determined until the braking operation amount Ba becomes equal to or less than the predetermined amount bx. Here, the predetermined amount bx is a preset predetermined value, and can be set to "0", for example. In the configuration of "bx=0", the padding continues until just before the operation of the brake operation member BP is completely finished, and ends when the operation of the brake operation member BP is finished. When the creep torque is large and/or the road surface gradient Kv is large, when the braking operation amount Ba starts to decrease, the vehicle JV may suddenly start moving at a higher acceleration than the driver intended. . However, since the raising is continued even after the vehicle JV starts running, the vehicle JV is smoothly started.

Further, in the controller ECU, the larger the gradient Kv of the road surface on which the vehicle JV stops, the larger the predetermined hydraulic pressure Pk is determined. Further, the predetermined hydraulic pressure Pk is determined to decrease as the manipulated variable Ba decreases. Since the predetermined hydraulic pressure Pk (raising hydraulic pressure) is determined according to the situation, the vehicle stopping control can appropriately raise the hydraulic pressure.

JV...Vehicle, SC...Brake control device, BP...Brake operation member, CW...Wheel cylinder, HU...Fluid unit (actuator), MA...Electric motor, SS...Stroke simulator, ECU...Controller, VW...Wheel speed sensor, Vw ... wheel speed (detected value of wheel speed sensor VW), Vx ... vehicle body speed, BA ... braking operation amount sensor, Ba ... braking operation amount (detection value of braking operation amount sensor BA), PW ... brake fluid pressure sensor, Pw ... Brake hydraulic pressure (the hydraulic pressure of the wheel cylinder CW, detected value of the brake hydraulic pressure sensor PW), Ps ... required hydraulic pressure (intermediate target value required by the manipulated variable Ba), Pt ... target hydraulic pressure (final target value of hydraulic pressure), Pk: predetermined hydraulic pressure (raising hydraulic pressure).

Claims (2)

an actuator for electrically adjusting brake fluid pressure in a vehicle wheel cylinder;
a controller that controls the actuator based on the amount of operation of the braking operation member of the vehicle;
In a vehicle braking control device comprising
The controller is
A braking control device for a vehicle, wherein the brake hydraulic pressure is increased by a predetermined hydraulic pressure at the time of determining whether the vehicle is in a stopped state. In the vehicle braking control device according to claim 1,
The controller is
A braking control device for a vehicle, wherein the raising is continued even if the vehicle starts to move when the operation amount is larger than a predetermined amount.

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