JP2022093451A - Braking control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking control device of a vehicle that executes automatic braking control and antiskid control, which can suppress the two controls from interfering with each other.

SOLUTION: A controller of a braking control device executes automatic braking control adjusting braking torque based on a deceleration target value of a vehicle corresponding to a distance between an object in front of the vehicle and the vehicle; and executes antiskid control adjusting the braking torque on the basis of a speed of a wheel. The controller executes feedback control so that a deceleration actual value comes closer to the deceleration target value; and reduces a control gain of the feedback control when executing the antiskid control. Further, the controller determines either of a mode of decreasing the braking torque and a mode of increasing the braking torque, in the antiskid control; and starts increasing the control gain when, during decreasing the control gain, a state of determining the mode of increasing has continued in all of wheels for a predetermined time.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a vehicle braking control device.

Patent Document 1 states that "the actual deceleration of the vehicle is reduced by increasing the braking force when the antiskid brake device (ABS) is activated during the operation of the automatic braking device and then the operation of the ABS is terminated. For the purpose of "preventing overshoot over speed", "an automatic braking device that automatically applies the brakes of each wheel to the vehicle under predetermined conditions and suppresses excessive braking force when braking the vehicle". The automatic braking device and the operating state detecting means for detecting each operating state of the ABS, and the boosting rate changing means for receiving a signal from the detecting means are provided. When the ABS operates during the operation of the automatic braking device and then the operation of the ABS ends, the increase rate of the brake pressure is changed to be lower than usual. Also, the degree to which the increase rate is lowered is changed. , The change is made according to the difference between the actual deceleration of the vehicle during the operation of the ABS and the target deceleration of the automatic braking device at the end of the operation of the ABS. "

By the way, when the anti-skid control is started during the execution of the automatic braking control, interference between the two controls may occur in addition to the above-mentioned overshoot problem. For example, when the coefficient of friction of the traveling road surface is low, the braking fluid pressure is increased by the automatic braking control, and the anti-skid control may be executed due to the increase in the braking fluid pressure. Automatic braking control attempts to increase braking fluid pressure to achieve the targeted deceleration, while anti-skid control attempts to reduce braking fluid pressure to reduce wheel slip. It is desired that the braking control device can suppress such control interference.

Japanese Unexamined Patent Publication No. 5-319233

It is an object of the present invention to provide a vehicle braking control device in which automatic braking control and anti-skid control are performed, in which interference between the two controls can be suitably suppressed.

The vehicle braking control device according to the present invention applies braking torque (Tq) to the wheels (WH) of the vehicle, and the vehicle corresponds to the distance (Ob) between the object in front of the vehicle and the vehicle. Automatic braking control for adjusting the braking torque (Tq) is executed based on the deceleration target value (Gt) of the above, and the braking torque (Tq) is applied based on the speed (Vw) of the wheel (WH). It is provided with a controller (ECU) that adjusts and executes anti-skid control that suppresses excessive slip (Sw) of the wheel (WH).

In the vehicle braking control device according to the present invention, the controller (ECU) calculates the deceleration target value (Gt) corresponding to the deceleration target value (Gt), and calculates the deceleration target value (Gt) and the deceleration target value (Gt). , Feedback control (PH, IG) is executed so that the deceleration actual value (Ge) approaches the deceleration target value (Gt) based on the deceleration actual value (Ge), and the anti-skid control is performed. When executed (Fa = 1), it is configured to reduce the control gain (Kc) of the feedback control (PH, IG). Further, the controller (ECU) may be configured to prohibit the execution of the feedback control (PH, IG) when the anti-skid control is executed (Fa = 1) (Kc = 0).

According to the above configuration, the effectiveness of the deceleration feedback control of the automatic braking control is weakened (or the deceleration feedback control is stopped and the open loop control is performed) during the execution of the anti-skid control. This can suppress the mutual interference of the two controls.

In the vehicle braking control device according to the present invention, the controller (ECU) has a reduction mode (Mg) for reducing the braking torque (Tq) based on the speed (Vw) in the anti-skid control, and a reduction mode (Mg). When one of the increasing modes (Mz) for increasing the braking torque (Tq) is determined and the control gain (Kc) is decreased, the increasing mode (WH) is used for all of the wheels (WH). The control gain (Kc) is increased when the state in which Mz) is determined is continued for a predetermined time (tk). For example, when the feedback control (PH, IG) is prohibited, the controller (ECU) is in a state where the increase mode (Mz) is determined for all of the wheels (WH) for a predetermined time (tk). ), The execution of the feedback control (PH, IG) is restarted.

According to the above configuration, it is determined that the wheel grip is being restored during the execution of anti-skid control. When it is affirmed that "the four wheels WH are in the state of the increase mode Mz and the duration Tk of that state is the predetermined time tk or more", the control gain Kc is increased. As a result, the effectiveness of the deceleration feedback control is increased, and the control accuracy of the automatic braking control is improved. That is, the feedback control of the automatic braking control can be preferably executed while the control interference is suppressed.

It is an overall block diagram for demonstrating the 1st Embodiment of the brake control device SC of the vehicle which concerns on this invention. It is a functional block diagram for demonstrating the arithmetic processing in a driving support controller ECJ, and a braking controller ECU. It is a functional block diagram for demonstrating the first arithmetic processing example of the automatic braking control block JC. It is a functional block diagram for demonstrating the second arithmetic processing example of the automatic braking control block JC. It is a control flow diagram for demonstrating the arithmetic processing of the control gain adjustment block KC. It is a schematic diagram for demonstrating the 2nd Embodiment of the brake control device SC of the vehicle which concerns on this invention. It is a schematic diagram for demonstrating the 3rd Embodiment of the brake control device SC of the vehicle which concerns on this invention.

<Symbols of constituent members, subscripts at the end of symbols, and movement / movement directions>
In the following description, components, arithmetic processing, signals, characteristics, and values having the same symbol, such as "ECU", have the same function. The subscripts "i" to "l" added to the end of each symbol are comprehensive symbols indicating which wheel they are related to. Specifically, "i" indicates the right front wheel, "j" indicates the left front wheel, "k" indicates the right rear wheel, and "l" indicates the left rear wheel. For example, in each of the four wheel cylinders, it is described as a right front wheel wheel cylinder CWi, a left front wheel wheel cylinder CWj, a right rear wheel wheel cylinder CWk, and a left rear wheel wheel cylinder CWl. Further, the subscripts "i" to "l" at the end of the symbol may be omitted. When the subscripts "i" to "l" are omitted, each symbol represents a general term for each of the four wheels. For example, "WH" represents each wheel and "CW" represents each wheel cylinder.

The subscripts "1" and "2" added to the end of each symbol are comprehensive symbols indicating which system the two braking systems are related to. Specifically, "1" indicates the first system, and "2" indicates the second system. For example, in the two master cylinder fluid paths, they are referred to as a first master cylinder fluid path HM1 and a second master cylinder fluid path HM2. Further, the subscripts "1" and "2" at the end of the symbol may be omitted. When the subscripts "1" and "2" are omitted, each symbol represents a general term for each of the two braking systems. For example, "HM" represents the master cylinder fluid path of each braking system.

<First Embodiment of the vehicle braking control device according to the present invention>
A first embodiment of the braking control device SC according to the present invention will be described with reference to the overall configuration diagram of FIG. The master cylinder CM is connected to the wheel cylinder CW via the master cylinder fluid path HM and the wheel cylinder fluid path HW. Here, the fluid path is a path for moving the braking liquid BF, which is the working liquid of the braking control device SC, and corresponds to the braking pipe, the flow path of the fluid unit, the hose, and the like. The inside of each fluid path is filled with the braking fluid BF. In the fluid path, the side closer to the reservoir RV (the side far from the wheel cylinder CW) is called the "upstream side" or "upper part", and the side closer to the wheel cylinder CW (the side far from the reservoir RV) is called. It is called "downstream" or "lower".

In a general vehicle, two fluid paths are adopted to ensure redundancy. The first system (the system related to the first master cylinder chamber Rm1) of the two fluid paths is connected to the wheel cylinders CWi and CWl. The second system (the system related to the second master cylinder chamber Rm2) of the two fluid paths is connected to the wheel cylinders CWj and CWk. That is, in the first embodiment, a so-called diagonal type (also referred to as "X type") is adopted as the two-system fluid path.

The vehicle equipped with the brake control device SC is provided with a braking operation member BP, a wheel cylinder CW, a reservoir RV, a master cylinder CM, and a brake booster BB.
The braking operation member (for example, the brake pedal) BP is a member operated by the driver to decelerate the vehicle. By operating the braking operation member BP, the braking torque Tq of the wheel WH is adjusted, and a braking force is generated on the wheel WH.

A rotating member (for example, a brake disc) KT is fixed to the wheel WH of the vehicle. Then, the brake caliper is arranged so as to sandwich the rotating member KT. The brake caliper is provided with a wheel cylinder CW. By increasing the pressure (braking fluid pressure) Pw of the braking fluid BF in the wheel cylinder CW, the friction member (for example, the brake pad) is pressed against the rotating member KT. Since the rotating member KT and the wheel WH are fixed so as to rotate integrally, a braking torque Tq is generated in the wheel WH by the frictional force generated at this time. This braking torque Tq causes a deceleration slip in the wheel WH, and as a result, a braking force is generated.

The reservoir (atmospheric pressure reservoir) RV is a tank for the working liquid, and the braking liquid BF is stored in the tank. The inside of the atmospheric pressure reservoir RV is divided into two parts by a partition plate SK. The first master reservoir chamber Ru1 is connected to the first master cylinder chamber Rm1, and the second master reservoir chamber Ru2 is connected to the second master cylinder chamber Rm2, respectively.

The master cylinder CM is mechanically connected to the braking operation member BP via a brake rod, a clevis (U-shaped link), or the like. The master cylinder CM is a tandem type, and the inside thereof is divided into first and second master cylinder chambers Rm1 and Rm2 by the first and second master pistons PL1 and PL2. When the braking operation member BP is not operated, the first and second master cylinder chambers Rm1 and Rm2 of the master cylinder CM and the reservoir RV (first and second master reservoir chambers Ru1 and Ru2) are in a communicating state. .. The master cylinder CM has two output ports consisting of first and second ports, receives the supply of braking fluid from the reservoir RV, and sets the first and second master cylinder hydraulic pressures Pm1 and Pm2 to the first and second master cylinders. Occurs on the second port. The first and second master cylinder fluid paths HM1 and HM2 are connected to the master cylinder CM (particularly, the first and second ports).

When the braking operation member BP is operated, the first and second master pistons PL1 and PL2 in the master cylinder CM are pushed, and the first and second master pistons PL1 and PL2 move forward. By this advance, the first and second master cylinder chambers Rm1 and Rm2 are cut off from the reservoir RV (particularly, the first and second master reservoir chambers Ru1 and Ru2). When the operation of the braking operation member BP is increased, the volumes of the master cylinder chambers Rm1 and Rm2 are reduced, and the braking liquid BF is pumped from the master cylinder CM toward the wheel cylinder CW.

The brake booster (simply also referred to as "booster") BB reduces the operating force Fp of the braking operation member BP by the driver. A negative pressure type booster BB is adopted. The negative pressure is formed by an engine or an electric negative pressure pump. As the booster BB, one using an electric motor as a drive source may be adopted (for example, an electric booster, an accumulator type hydraulic booster).

Further, the vehicle is provided with a wheel speed sensor VW, a steering angle sensor SA, a yaw rate sensor YR, a front-rear acceleration sensor GX, a lateral acceleration sensor GY, a braking operation amount sensor BA, an operation switch ST, and a distance sensor OB.
Each wheel WH of the vehicle is provided with a wheel speed sensor VW to detect the wheel speed Vw. The wheel speed Vw signal is used for independent control on each wheel such as anti-skid control that suppresses the locking tendency (that is, excessive deceleration slip) of the wheel WH.

The steering operation member (for example, the steering wheel) is provided with a steering angle sensor SA so as to detect the steering angle Sa. The body of the vehicle is equipped with a yaw rate sensor YR to detect the yaw rate (yaw angular velocity) Yr. Further, the front-rear acceleration sensor GX and the lateral acceleration sensor GX and the lateral acceleration so as to detect the acceleration (front-back acceleration) Gx in the front-rear direction (traveling direction) and the acceleration (lateral acceleration) Gy in the lateral direction (direction perpendicular to the traveling direction) of the vehicle. An acceleration sensor GY is provided. These signals are used for vehicle motion control such as vehicle stabilization control (so-called ESC) that suppresses excessive oversteer behavior and understeer behavior.

A braking operation amount sensor BA is provided so as to detect the operation amount Ba of the braking operation member BP (brake pedal) by the driver. As the braking operation amount sensor BA, a master cylinder hydraulic pressure sensor PM that detects the hydraulic pressure (master cylinder hydraulic pressure) Pm in the master cylinder CM, an operation displacement sensor SP that detects the operation displacement Sp of the braking operation member BP, and braking. At least one of the operating force sensors FP that detects the operating force Fp of the operating member BP is adopted. That is, at least one of the master cylinder hydraulic pressure Pm, the operation displacement Sp, and the operation force Fp is detected as the braking operation amount Ba by the operation amount sensor BA.

The braking operation member BP is provided with an operation switch ST. The operation switch ST detects whether or not the driver operates the braking operation member BP. When the braking operation member BP is not operated (that is, during non-braking), the braking operation switch ST outputs an off signal as the operation signal St. On the other hand, when the braking operation member BP is operated (that is, during braking), an on signal is output as an operation signal St.
The wheel speed Vw, steering angle Sa, yaw rate Yr, front-rear acceleration Gx, lateral acceleration Gy, braking operation amount Ba, and braking operation signal St detected by each sensor (VW or the like) are input to the controller ECU. In the controller ECU, the vehicle body speed Vx is calculated based on the wheel speed Vw.

The vehicle is provided with a distance sensor OB so as to detect a distance (relative distance) Ob between an object (another vehicle, a fixed object, a person, a bicycle, etc.) existing in front of the own vehicle and the own vehicle. .. For example, a camera, a radar, or the like is adopted as the distance sensor OB. The distance Ob is input to the controller ECJ. In the controller ECJ, the required deceleration Gr is calculated based on the relative distance Ob.

≪Electronic control unit ECU≫
The braking control device SC is composed of a controller ECU and a fluid unit HU.
The controller (also referred to as "electronic control unit") ECU is composed of an electric circuit board on which a microprocessor MP or the like is mounted and a control algorithm programmed in the microprocessor MP. The controller ECU is network-connected so as to share a signal (detection value, calculated value, etc.) with another controller via an in-vehicle communication bus BS. For example, the braking controller ECU is connected to the driving support controller ECJ through the communication bus BS. The vehicle body speed Vx is transmitted from the braking controller ECU to the driving support controller ECJ. On the other hand, from the driving support controller ECJ to the braking controller ECU, the required deceleration Gr (target) for executing automatic braking control so as to avoid a collision with an obstacle (or to reduce damage at the time of a collision). Value) is sent.

The controller ECU (electronic control unit) controls the electric motor ML of the fluid unit HU and three different types of solenoid valves UP, VI, and VO. Specifically, the drive signals Up, Vi, and Vo for controlling various solenoid valves UP, VI, and VO are calculated based on the control algorithm in the microprocessor MP. Similarly, the drive signal Ml for controlling the electric motor ML is calculated.

The controller ECU is provided with a drive circuit DR so as to drive the solenoid valve UP, VI, VO, and the electric motor ML. In the drive circuit DR, a bridge circuit is formed by switching elements (power semiconductor devices such as MOS-FETs and IGBTs) so as to drive the electric motor ML. Based on the motor drive signal Ml, the energization state of each switching element is controlled, and the output of the electric motor ML is controlled. Further, in the drive circuit DR, the energization state (that is, the excitation state) thereof is controlled by the switching element based on the drive signals Up, Vi, and Vo so as to drive the solenoid valves UP, VI, and VO. The drive circuit DR is provided with an electric motor ML and an energization amount sensor for detecting the actual energization amount of the solenoid valves UP, VI, and VO. For example, a current sensor is provided as an energization amount sensor, and the supply current to the electric motor ML and the solenoid valves UP, VI, and VO is detected.

The braking controller ECU includes braking operation amount Ba (Pm, Sp, Fp), braking operation signal St, downstream hydraulic pressure Pp, wheel speed Vw, yaw rate Yr, steering angle Sa, front-rear acceleration Gx, lateral acceleration Gy, etc. Is entered. Further, the required deceleration Gr is input from the driving support controller ECJ via the communication bus BS.

For example, in the braking controller ECU, anti-skid control is executed so as to suppress excessive deceleration slip (for example, wheel lock) of the wheel WH based on the wheel speed Vw. In the controller ECU, vehicle stabilization control (so-called ESC) that suppresses unstable behavior (excessive oversteer behavior, understeer behavior) of the vehicle is executed based on the actual yaw rate Yr or the like. Further, in the controller ECU, automatic braking control is executed so as to avoid a collision with an obstacle (or to reduce damage in the event of a collision) based on the required deceleration Gr.

≪Fluid unit HU≫
The fluid unit HU is connected to the first and second master cylinder fluid passages HM1 and HM2. At the portions Bw1 and Bw2 in the fluid unit HU, the master cylinder fluid passages HM1 and HM2 are branched into the wheel cylinder fluid passages HWi to HWl and connected to the wheel cylinders CWi to CWl. Specifically, the first master cylinder fluid passage HM1 is branched into the wheel cylinder fluid passages HWi and HWl at the first branch portion Bw1. Wheel cylinders CWi and CWl are connected to the wheel cylinder fluid passages HWi and HWl. Similarly, the second master cylinder fluid path HM2 is branched into the wheel cylinder fluid paths HWj and HWk at the second branch portion Bw2. Wheel cylinders CWj and CWk are connected to the wheel cylinder fluid paths HWj and HWk.

The fluid unit HU is composed of an electric pump DL, a low pressure reservoir RL, a pressure regulating valve UP, a master cylinder hydraulic pressure sensor PM, a downstream hydraulic pressure sensor PP, an inlet valve VI, and an outlet valve VO.
The electric pump DL is composed of one electric motor ML and two fluid pumps QL1 and QL2. The electric motor (reflux motor) ML is controlled by the controller ECU based on the drive signal Ml. The first and second fluid pumps QL1 and QL2 are integrally rotated and driven by the electric motor ML. The brake fluid BF is pumped from the first and second suction portions Bs1 and Bs2 located upstream of the first and second pressure regulating valves UP1 and UP2 by the first and second fluid pumps QL1 and QL2. The pumped brake fluid BF is discharged to the first and second discharge portions Bt1 and Bt2 located downstream of the first and second pressure regulating valves UP1 and UP2. Here, the electric pump DL is rotated only in one direction. The first and second low-pressure reservoirs RL1 and RL2 are provided on the suction side of the first and second fluid pumps QL1 and QL2.

The first and second pressure regulating valves UP1 and UP2 are provided in the first and second master cylinder fluid passages HM1 and HM2. As a pressure regulating valve UP (general term for the first and second pressure regulating valves UP1 and UP2), a linear solenoid valve (lift amount) in which the valve opening amount (lift amount) is continuously controlled based on the energized state (for example, supply current) ( A "proportional valve" or "differential pressure valve") is adopted. The pressure regulating valve UP is controlled by the controller ECU based on the drive signal Up (general term for the first and second drive signals Up1 and Up2). Here, as the first and second pressure regulating valves UP1 and UP2, a normally open solenoid valve is adopted.

The controller ECU determines the target energization amount of the pressure regulating valve UP based on the calculation results of vehicle stabilization control, automatic braking control, etc. (for example, the target hydraulic pressure of the wheel cylinder CW). The drive signal Up is determined based on the target energization amount. Then, the energization amount (current) to the pressure regulating valve UP is adjusted according to the drive signal Up, and the valve opening amount of the pressure regulating valve UP is adjusted.

When the fluid pump QL is driven, a reflux (flow of the circulating brake fluid BF) of "Bs-> RL-> QL-> Bt-> UP-> Bs" is formed. When the pressure regulating valve UP is not energized and the normally open type pressure regulating valve UP is in the fully open state, the hydraulic pressure on the upstream side of the pressure regulating valve UP (that is, the master cylinder hydraulic pressure Pm) and the pressure regulating valve UP It is substantially the same as the hydraulic pressure Pp on the downstream side (that is, the braking hydraulic pressure Pw when the solenoid valves VI and VO are not driven).

The amount of electricity supplied to the normally open type pressure regulating valve UP is increased, and the amount of valve opening of the pressure regulating valve UP is decreased. The pressure regulating valve UP throttles the recirculation of the braking fluid BF, and the orifice effect increases the downstream hydraulic pressure Pp (= Pw) from the upstream hydraulic pressure Pm. That is, the differential pressure (Pp> Pm) between the upstream hydraulic pressure Pm and the downstream hydraulic pressure Pp is adjusted by the electric pump DL and the pressure regulating valve UP. By controlling the electric pump DL and the pressure regulating valve UP, the downstream hydraulic pressure Pp (that is, the braking fluid pressure Pw) is increased from the master cylinder hydraulic pressure Pm corresponding to the operation of the braking operation member BP. .. For example, when the braking operation member BP is not operated, "Pm = 0", but the braking fluid pressure Pw is increased to a value larger than "0".

The first and second master cylinder hydraulic pressure sensors PM1 and PM2 are provided upstream of the pressure regulating valve UP so as to detect the first and second master cylinder hydraulic pressures Pm1 and Pm2. Further, in the downstream portion of the pressure regulating valve UP, first and second downstream side hydraulic pressure sensors PP1 and PP2 are provided so as to detect the first and second downstream side hydraulic pressures Pp1 and Pp2. At least one of the four hydraulic pressure sensors PM1, PM2, PP1 and PP2 can be omitted.

The master cylinder fluid passage HM is branched (branched) into each front wheel cylinder fluid passage HW at a portion (branch portion) Bw on the downstream side of the pressure regulating valve UP. The wheel cylinder fluid passage HW is provided with an inlet valve VI and an outlet valve VO. As the inlet valve VI, a normally open type on / off solenoid valve is adopted. Further, as the outlet valve VO, a normally closed type on / off solenoid valve is adopted. Here, the on / off solenoid valve is a 2-port 2-position switching type solenoid valve having two positions, an open position and a closed position. The solenoid valves VI and VO are controlled by the controller ECU based on the drive signals Vi and Vo. The braking fluid pressure Pw of each wheel can be independently controlled by the inlet valve VI and the outlet valve VO.

In the inlet valve VI and the outlet valve VO, the configuration related to each wheel WH is the same. A normally open type inlet valve VI is provided in the wheel cylinder fluid path HW (fluid path connecting the portion Bw and the wheel cylinder CW). The wheel cylinder fluid passage HW is connected to the low pressure reservoir RL at the downstream portion of the inlet valve VI via the normally closed outlet valve VO. For example, in the independent control of each wheel (anti-skid control, vehicle stabilization control, etc.), the inlet valve VI is closed and the outlet valve VO is opened in order to reduce the hydraulic pressure Pw in the wheel cylinder CW. To. The inflow of the braking fluid BF from the inlet valve VI is blocked, the braking fluid BF in the wheel cylinder CW flows out to the low pressure reservoir RL, and the braking fluid pressure Pw is reduced. Further, in order to increase the braking fluid pressure Pw, the inlet valve VI is opened and the outlet valve VO is closed. The outflow of the braking fluid BF to the low pressure reservoir RL is prevented, the downstream hydraulic pressure Pp adjusted by the pressure regulating valve UP is introduced into the wheel cylinder CW, and the braking fluid pressure Pw is increased.

The braking torque Tq of the wheel WH is increased / decreased (adjusted) by increasing / decreasing the braking fluid pressure Pw. When the braking fluid pressure Pw is increased, the force with which the friction material is pressed against the rotating member KT is increased, and the braking torque Tq is increased. As a result, the braking force of the wheel WH is increased. On the other hand, when the braking fluid pressure Pw is reduced, the pressing force of the friction material against the rotating member KT is reduced, and the braking torque Tq is reduced. As a result, the braking force of the wheel WH is reduced.

<Calculation processing in the driving support controller ECJ and the braking controller ECU>
The arithmetic processing in the driving support controller ECJ and the braking controller ECU will be described with reference to the functional block diagram of FIG. The driving support controller ECJ calculates the required deceleration Gr in the automatic braking control. The required deceleration Gr is transmitted to the braking controller ECU via the communication bus BS. The braking controller ECU controls the fluid unit HU (ML, UP, etc.) so as to adjust the braking torque Tq of the wheel WH based on the required deceleration Gr. Further, in the controller ECU, anti-skid control is executed so as to suppress an excessive deceleration slip of the wheel WH.

The vehicle should detect the distance (relative distance) Ob between the object (other vehicle, fixed object, bicycle, person, animal, etc.) existing ahead of the vehicle and the vehicle. A distance sensor OB is provided. For example, a camera, radar, or the like is used as the distance sensor OB. Further, when the fixed object is stored in the map information, the navigation system can be used as the distance sensor OB. The detected relative distance Ob is input to the driving support controller ECJ.

The driving support controller ECJ includes a collision margin time calculation block TC, a vehicle head time calculation block TW, and a required deceleration calculation block GR.
In the collision margin time calculation block TC, the collision margin time Tc is calculated based on the relative distance Ob between the object in front of the vehicle and the own vehicle. The collision margin time Tc is the time until the own vehicle and the object collide. Specifically, the collision margin time Tc is determined by dividing the relative distance Ob between the object in front of the vehicle and the own vehicle by the speed difference (that is, the relative speed) between the obstacle and the own vehicle. To. Here, the relative velocity is calculated by differentiating the relative distance Ob with respect to time.

In the vehicle head time calculation block TW, the vehicle head time Tw is calculated based on the relative distance Ob and the vehicle body speed Vx. The head time Tw is the time until the own vehicle reaches the current position of the object in front. Specifically, the vehicle head time Tw is calculated by dividing the relative distance Ob by the vehicle body speed Vx. When the object in front of the own vehicle is stationary, the collision margin time Tc and the vehicle head time Tw match. The vehicle body speed Vx is acquired from the vehicle body speed calculation block VX of the controller ECU via the communication bus BS.

In the required deceleration calculation block GR, the required deceleration Gr is calculated based on the collision margin time Tc and the vehicle head time Tw. The required deceleration Gr is a target value for deceleration of the own vehicle in order to avoid a collision between the own vehicle and the object in front. The required deceleration Gr is calculated according to the calculation map Zgr so that the larger the collision margin time Tc is, the smaller it is (or the smaller the collision margin time Tc is, the larger it is). Further, the required deceleration Gr can be adjusted based on the vehicle head time Tw. The required deceleration Gr is adjusted based on the vehicle head time Tw so that the larger the vehicle head time Tw is, the smaller the required deceleration Gr is (or the smaller the vehicle head time Tw is, the larger the required deceleration Gr is). .. The required deceleration Gr is input to the target deceleration calculation block GT in the braking controller ECU via the communication bus BS.

Each wheel WH of the vehicle is provided with a wheel speed sensor VW so as to detect the rotation speed (wheel speed) Vw of the wheel WH. The detected wheel speed Vw is input to the controller ECU. The braking controller ECU includes a vehicle body speed calculation block VX, a wheel acceleration calculation block DV, a wheel slip calculation block SW, an anti-skid control block AC, an indicated deceleration calculation block GS, a target deceleration calculation block GT, and an actual deceleration calculation block GE. , Automatic braking control block JC, and drive circuit DR.

The vehicle body speed calculation block VX calculates the vehicle body speed Vx based on the wheel speed Vw. For example, during non-braking including acceleration of the vehicle, the vehicle body speed Vx is calculated based on the slowest of the four wheel speeds Vw (the slowest wheel speed). Further, at the time of braking, the vehicle body speed Vx is calculated based on the fastest of the four wheel speeds Vw (fastest wheel speed). Further, in the calculation of the vehicle body speed Vx, a limit may be provided in the amount of time change thereof. That is, the upper limit value αup of the increase gradient of the vehicle body speed Vx and the lower limit value αdn of the decrease gradient are set, and the change of the vehicle body speed Vx is constrained by the upper and lower limit values αup and αdn. The calculated Vx is transmitted to the vehicle head time Tw of the controller ECJ.

The wheel acceleration calculation block DV calculates the wheel acceleration dV (the amount of time change of the wheel speed Vw) based on the wheel speed Vw. Specifically, the wheel speed Vw is time-differentiated and the wheel acceleration dV is calculated.

The wheel slip calculation block SW calculates the deceleration slip (also referred to as "wheel slip") Sw of the wheel WH based on the vehicle body speed Vx and the wheel speed Vw. The wheel slip Sw is a state quantity indicating the degree of grip of the wheel WH with respect to the traveling road surface. For example, as the wheel slip Sw, the deceleration slip speed (deviation between the vehicle body speed Vx and the wheel speed Vw) hV of the wheel WH is calculated (hV = Vx-Vw). Further, as the wheel slip Sw, a wheel slip ratio (= hV / Vx) in which the slip speed (speed deviation) hV is made non-dimensional by the vehicle body speed Vx can be adopted.

In the anti-skid control block AC, anti-skid control is executed based on the wheel acceleration dV and the wheel slip Sw. The adjustment of the braking fluid pressure Pw by the anti-skid control is performed by "decrease mode (decompression mode) Mg for reducing the braking torque Tq (that is, braking fluid pressure Pw)" and "braking torque Tq (that is, braking fluid pressure Pw)". ) Is increased by selecting any one of the "increasing modes (pressure increasing modes) Mz". Here, the decrease mode Mg and the increase mode Mz are collectively referred to as "control mode" and are determined by the control mode selection block MD included in the anti-skid control block AC.

A plurality of threshold values are preset in the control mode selection block MD so as to determine each control mode. Based on the mutual relationship between these threshold values and "wheel acceleration dV and wheel slip Sw", any one of the decrease mode Mg and the increase mode Mz is selected. .. In addition, in the control mode selection block MD, the detail ratio Dg of the outlet valve VO and the detail ratio Dz of the inlet valve VI are determined. Here, the "depth ratio" is the ratio of the energization time (on time) per unit time. The solenoid valves VI and VO are driven and the braking fluid pressure Pw of the wheel cylinder CW is adjusted based on the selected control mode and the determined duty ratio. In addition, the drive signal Ml of the electric motor ML is calculated so as to return the brake fluid BF from the low pressure reservoir RL to the upstream portion Bt of the inlet valve VI.

When the reduction mode Mg is selected and the braking fluid pressure Pw is reduced by the anti-skid control, the inlet valve VI is closed and the outlet valve VO is opened. That is, the boost duty ratio Dz is determined to be "100% (constant energization)", and the outlet valve VO is driven based on the pressure reducing duty ratio Dg. The braking fluid BF in the wheel cylinder CW is moved to the low pressure reservoir RL, and the braking fluid pressure Pw is reduced. Here, the depressurizing speed (time gradient in the decrease of the braking fluid pressure Pw) is determined by the duty ratio Dg of the outlet valve VO. The "100%" decompression duty ratio Dg corresponds to the constantly open state of the outlet valve VO, and the braking fluid pressure Pw is sharply reduced. By "Dg = 0% (non-energized)", the closed position of the outlet valve VO is achieved.

When the increase mode Mz is selected and the braking fluid pressure Pw is increased by the anti-skid control, the inlet valve VI is opened and the outlet valve VO is closed. That is, the reduced pressure duty ratio Dg is determined to be "0%", and the inlet valve VI is driven based on the increased pressure duty ratio Dz. The braking fluid BF is moved to the wheel cylinder CW, and the braking fluid pressure Pw is increased. The pressure increase speed (time gradient in the increase of the braking fluid pressure) is adjusted by the duty ratio Dz of the inlet valve VI. The boosting duty ratio Dz of "0%" corresponds to the constantly open state of the inlet valve VI, and the braking fluid pressure Pw is rapidly increased. By "Dz = 100% (constant energization)", the closed position of the inlet valve VI is achieved.

When it is necessary to maintain the braking fluid pressure Pw by the anti-skid control, the outlet valve VO or the inlet valve VI is always closed in the decrease mode Mg or the increase mode Mz. Specifically, when it is necessary to maintain the braking hydraulic pressure Pw in the reduction mode Mg, the duty ratio Dg of the outlet valve VO is determined to be "0% (normally closed state)". Further, when it is necessary to maintain the braking fluid pressure Pw in the increase mode Mz, the duty ratio Dz of the inlet valve VI is determined to be "100% (normally closed state)".

In the anti-skid control block AC, the friction coefficient Mu of the traveling road surface is estimated and calculated based on the deceleration Ge of the vehicle body at the time when the anti-skid control is started (that is, when the reduction mode Mg is selected for the first time). Specifically, the larger the actual deceleration Ge at that time point, the larger the friction coefficient Mu is estimated, and the smaller the actual deceleration Ge, the smaller the friction coefficient Mu is determined. The estimated friction coefficient Mu is input to the automatic braking control block JC.

In the anti-skid control block AC, various operation flags (signals) Fa and Fm indicating the execution status of the anti-skid control, the selected control mode, and the like are determined. For example, when the anti-skid control is not executed, the operation flag Fa is set to "0". On the other hand, when the anti-skid control is executed, the operation flag Fa is set to "1". That is, the operation flag Fa is a signal indicating the execution of the anti-skid control. Further, in the anti-skid control block AC, when the increase mode Mz is selected for all the wheels WH (referred to as “four-wheel pressure increase mode state”), the operation flag Fm is determined to be “1”. On the other hand, when the reduction mode Mg is selected on at least one of the four wheels, the operation flag Fm is calculated to "0". That is, the operation flag Fm is a signal indicating the four-wheel pressure boost mode state. The operation flags Fa and Fm are input to the automatic braking control block JC.

In the indicated deceleration calculation block GS, the indicated deceleration Gs is calculated based on the braking operation amount Ba. The indicated deceleration Gs is a target value for vehicle deceleration generated by the operation of the braking operation member BP by the driver. The indicated deceleration Gs is calculated to be "0" when the braking operation amount Ba is less than the predetermined value bo according to the calculation map Zgs. Then, when the braking operation amount Ba is equal to or higher than the predetermined value bo, the indicated deceleration Gs is calculated so as to monotonically increase from "0". Here, the predetermined value bo is a preset constant corresponding to the play of the braking operation member BP.

In the target deceleration calculation block GT, the target deceleration Gt is calculated based on the required deceleration Gr and the indicated deceleration Gs. The target deceleration Gt is the final target value for vehicle deceleration in the automatic braking control. In the target deceleration calculation block GT, the value of the required deceleration Gr and the indicated deceleration Gs, whichever has the larger absolute value, is determined as the target deceleration Gt. Therefore, in the case of "| Gr |> | Gs |", the automatic braking control is executed. However, in the case of "| Gr | <| Gs |", the automatic braking control is not executed because the driver has already decelerated the vehicle.

In the actual deceleration calculation block GE, the actual deceleration Ge is calculated based on the vehicle body speed Vx. The actual deceleration Ge is an actual value corresponding to the target deceleration Gt. Specifically, the vehicle body speed Vx is time-differentiated, and the actual deceleration Ge is calculated. Further, the front-back acceleration (front-back deceleration) Gx is adopted for the calculation of the actual deceleration Ge. In this case, the front-rear acceleration Gx (detection value) is determined as it is as the actual deceleration Ge. The front-back acceleration Gx is detected by the front-back acceleration sensor GX, and the front-back acceleration Gx includes the gradient of the traveling road surface. Therefore, in the calculation of the actual deceleration Ge, the differential value of the vehicle body speed Vx is preferable to the front-rear acceleration Gx. Further, the actual deceleration Ge may be calculated based on the differential value of the vehicle body speed Vx and the front-rear acceleration Gx so as to improve the robustness.

In the automatic braking control block JC, automatic braking control is executed based on the target deceleration Gt and the actual deceleration Ge. In the automatic braking control block JC, feedback control based on vehicle deceleration is executed so that the actual deceleration Ge matches the target deceleration Gt. In the automatic braking control block JC, the target energization amount It for calculating the drive signal Up of the pressure regulating valve UP is determined.

The automatic braking control block JC includes a control gain adjustment block KC. In the control gain adjustment block KC, the control gain Kc of the feedback control is adjusted based on the operation flags Fa, Fm, and the road surface friction coefficient Mu. As a result, mutual interference between the automatic braking control and the anti-skid control can be suppressed, and the automatic braking control can be efficiently executed. The details of the automatic braking control block JC will be described later.

In the drive circuit DR, the solenoid valves VI, VO, UP, and the recirculation motor ML are driven based on the increase / decrease duty ratios Dz, Dg, the target energization amount It, and the drive signal Ml. In the drive circuit DR, the drive signal Vi for the inlet valve VI is calculated based on the boost duty ratio Dz so as to execute the anti-skid control, and the drive signal Vi for the outlet valve VO is calculated based on the decompression duty ratio Dg. The signal Vo is determined. Further, the drive signal Ml is calculated so as to drive the electric motor ML at a preset predetermined rotation speed.

In the drive circuit DR, the drive signal Up for the pressure regulating valve UP is determined based on the target energization amount It so as to execute the automatic braking control. Further, the target rotation speed of the electric motor ML is determined based on the target deceleration Gt, and the drive signal Ml is calculated based on this. The target rotation speed of the electric motor ML is calculated to be larger as the target deceleration Gt is larger, and smaller as the target deceleration Gt is smaller. When the automatic braking control and the anti-skid control are executed at the same time, the electricity is based on the larger value of the predetermined rotation speed for the anti-skid control and the target rotation speed for the automatic braking control. The motor ML is driven. Further, also in the automatic braking control, the electric motor ML may be driven at a predetermined predetermined rotation speed.

In the drive circuit DR, the energization state of the solenoid valve VI, VO, UP, and the electric motor ML is controlled by the switching element (power semiconductor device) based on the drive signals Vi, Vo, Up, and Ml. As a result, the solenoid valves VI, VO, UP, and the electric motor ML are driven, and automatic braking control, anti-skid control, and the like are executed.

<Example of the first calculation process of the automatic braking control block JC>
A first calculation processing example of the automatic braking control block JC will be described with reference to the functional block diagram of FIG. In the deceleration feedback control of the automatic braking control block JC, the target energization amount of the pressure regulating valve UP so that the actual deceleration Ge matches the target deceleration Gt based on the target deceleration Gt and the actual deceleration Ge. It is calculated. The braking torque Tq is adjusted by the deceleration feedback control, and finally the deceleration of the target vehicle is achieved. The automatic braking control block JC employs a cascade control configuration including a plurality of feedback control loops.

In cascade control, the target value of the inner feedback control loop is determined by the output signal of the outer feedback control loop that measures the controlled object. The inner feedback control loop controls the controlled object with a smaller time delay than the outer one. This improves responsiveness and stabilizes the overall feedback control. In the first arithmetic processing example, the outermost control loop is based on the target value Gt related to the deceleration of the vehicle and the actual value Ge (referred to as “deceleration feedback control”). A control loop (referred to as "hydraulic feedback control") based on the target value Pt related to the braking hydraulic pressure and the actual value Pp is formed inside the target value Pt. The innermost side includes a target value It related to the energization amount of the pressure regulating valve UP and a control loop (referred to as "energization amount feedback control") based on the actual value Ia.

The automatic braking control block JC includes the indicated hydraulic pressure calculation block PS, the compensating hydraulic pressure calculation block PH, the control gain adjustment block KC, the target hydraulic pressure calculation block PT, the indicated energization amount calculation block IS, the compensated energization amount calculation block IH, and It is composed of the target energization amount calculation block IT.

In the indicated hydraulic pressure calculation block PS, the indicated hydraulic pressure Ps is calculated based on the target deceleration Gt. The indicated hydraulic pressure Ps is one of the target values of the hydraulic pressure. The indicated hydraulic pressure Ps is determined to increase as the target deceleration Gt increases according to the calculation map Zps. A predetermined upper limit value po (preset constant) is set in the indicated hydraulic pressure Ps. The indicated hydraulic pressure calculation block PS corresponds to the deceleration feedforward control for improving the responsiveness of the deceleration feedback control.

The target deceleration Gt and the actual deceleration Ge are compared, and their deviation hG (= Gt-Ge) is calculated. The deceleration deviation hG is input to the compensation hydraulic pressure calculation block PH. Compensation hydraulic pressure calculation In the block PH, the compensation hydraulic pressure Ph is calculated based on the deviation hG. In the control of only the indicated hydraulic pressure Ps, an error between the actual deceleration Ge and the target deceleration Gt actually occurs. Compensation hydraulic pressure Ph is calculated so as to reduce this error. Like the indicated hydraulic pressure Ps, the compensating hydraulic pressure Ph is also one of the target values of the hydraulic pressure. The compensating hydraulic pressure Ph is determined to be "0" when the deviation hG is in the range of the value -ho to the value ho (that is, in the case of "-ho <hG <ho") according to the calculation map Zph. When the deviation hG is equal to or less than a predetermined value −ho, the compensating hydraulic pressure Ph is increased toward “0” with an increasing gradient Kc (variable value) as the deviation hG increases. When the deviation hG is equal to or greater than the predetermined value ho, the compensating hydraulic pressure Ph is increased from "0" at the increasing gradient Kc as the deviation hG increases. Here, the predetermined value ho is a preset constant, and forms a dead zone provided so that the feedback control is not complicated.

The compensating hydraulic pressure calculation block PH corresponds to deceleration feedback control. The deceleration feedback control finally adjusts the braking torque Tq so as to achieve the deceleration of the target vehicle. The direct control target of the deceleration feedback control is the hydraulic pressure (downstream side hydraulic pressure) Pp of the downstream portion Bt of the pressure regulating valve UP. Here, in the calculation map Zph for calculating the compensation hydraulic pressure Ph, the increasing gradient Kc is the control gain of the deceleration feedback control. The control gain Kc is for adjusting the effectiveness of the feedback control. For example, when the control gain Kc is excessive, the system is unstable and overshoot is likely to occur. On the other hand, when the control gain Kc is too small, the sensitivity is low and it is difficult to achieve the target value. Therefore, the control gain Kc needs to be set to an appropriate value.

Feedback control is also referred to as "PID control". The control gain Kc is a proportional gain (proportional term) in the feedback control. Therefore, the compensating hydraulic pressure Ph is determined based on a proportional factor (= Kc × hG) of the deceleration deviation hG. Although not shown, the compensating hydraulic pressure Ph may be calculated by adding any one of the differential element of the deviation hG and the integral element of the deviation hG. In this case, the differential element is calculated by multiplying the deviation hG with respect to time and multiplying it with the differential gain (differential term). Further, the integral element is determined by time-integrating the deviation hG and multiplying it by the integral gain (integral term).

In the control gain adjustment block KC, the control gain Kc is determined based on the anti-skid control operation flags Fa, Fm, and the friction coefficient Mu. When the anti-skid control is not executed, the control gain Kc is determined to be a preset predetermined value ko (nominal value). When the anti-skid control is executed, the control gain Kc is adjusted so as to suppress the control interference. Details of the method for determining the control gain Kc will be described later.

In the target hydraulic pressure calculation block PT, the target hydraulic pressure Pt is calculated based on the indicated hydraulic pressure Ps and the compensation hydraulic pressure Ph. The target hydraulic pressure Pt is a final hydraulic pressure target value. Specifically, the compensating hydraulic pressure Ph is added to the indicated hydraulic pressure Ps to determine the target hydraulic pressure Pt.

The indicated energization amount calculation block IS calculates the indicated energization amount Is based on the target hydraulic pressure Pt. The indicated energization amount Is is one of the target values of the energization amount to the pressure regulating valve UP. The indicated energization amount Is is determined to increase as the target hydraulic pressure Pt increases according to the calculation map Zis. A predetermined upper limit value so (preset constant) is set in the indicated energization amount Is. The indicated energization amount calculation block IS corresponds to the hydraulic feedforward control for improving the responsiveness of the hydraulic feedback control.

The target hydraulic pressure Pt and the downstream hydraulic pressure Pp (detected value of the downstream hydraulic pressure sensor PP) are compared, and their deviation hP (= Pt-Pp) is calculated. The hydraulic pressure deviation hP is input to the compensation energization amount calculation block IH. In the compensation energization amount calculation block IH, the compensation energization amount Ih is calculated based on the hydraulic pressure deviation hP. In the control of only the indicated energization amount Is, an error between the downstream hydraulic pressure Pp and the target hydraulic pressure Pt actually occurs. The compensated energization amount Ih is calculated so as to reduce this error. Like the indicated energization amount Is, the compensated energization amount Ih is also one of the target values of the hydraulic pressure. The compensated energization amount Ih is increased with an increasing gradient kp as the hydraulic pressure deviation hP increases according to the calculation map Zih. Here, the increasing gradient kp is a preset constant.

The compensation energization amount calculation block IH corresponds to the hydraulic pressure feedback control. The increasing gradient kp of the compensated energization amount Ih is the control gain (proportional gain) in the hydraulic pressure feedback control. Therefore, the compensated energization amount Ih is determined based on the proportional element (= kp × hP) of the hydraulic pressure deviation hP. Similar to the compensation hydraulic pressure calculation block PH, any one of the differential element and the integral element of the hydraulic pressure deviation hP can be added to the calculation of the compensation energization amount Ih. Further, a dead zone may be provided in the calculation of the compensation energization amount Ih.

The target energization amount calculation block IT calculates the target energization amount It based on the indicated energization amount Is and the compensated energization amount Ih. The target energization amount It is a target value of the final energization amount. Specifically, the compensation energization amount Ih is added to the indicated energization amount Is, and the target energization amount It is determined. The target energization amount It is input to the drive circuit DR.

In the drive circuit DR, the energization amount feedback control is executed for the pressure regulating valve UP based on the target energization amount It. The drive circuit DR is provided with an energization amount sensor IA so as to detect the actual energization amount (for example, current value) Ia to the pressure regulating valve UP. Then, the energization amount feedback control is performed so that the actual energization amount Ia matches the target energization amount It. Specifically, as with other feedback controls, the deviation hI between the target energization amount It and the actual energization amount Ia is calculated, and the deviation hI is adjusted so as to approach "0" based on the energization amount deviation hI. The amount of electricity supplied to the pressure valve UP is adjusted.

<Second arithmetic processing example of automatic braking control block JC>
A second example of arithmetic processing of the automatic braking control block JC will be described with reference to the functional block diagram of FIG. In the first arithmetic processing example, the “target deceleration Gt and the deceleration feedback control loop based on the actual deceleration Ge” and the “target hydraulic pressure Pt and the hydraulic pressure feedback control loop based on the actual hydraulic pressure Pp”. Was included. In the second arithmetic processing example, the hydraulic feedback control loop is omitted. Along with this, the downstream side hydraulic pressure sensor PP may be omitted in the fluid unit HU. This is based on the fact that the pressure adjustment amount by the pressure adjustment valve UP changes proportionally according to the energization amount (that is, the supply current) to the pressure adjustment valve UP. In the second calculation processing example, in the deceleration feedback control based on the target deceleration Gt and the actual deceleration Ge, the energization amount of the pressure regulating valve UP is directly controlled.

The automatic braking control block JC is composed of an indicated energization amount calculation block IR, a compensation energization amount calculation block IG, a control gain adjustment block KC, and a target energization amount calculation block IT.
The indicated energization amount calculation block IR calculates the indicated energization amount Ir (one of the target values of the energization amount) based on the target deceleration Gt. The indicated energization amount calculation block IR corresponds to the deceleration feedforward control for improving the responsiveness of the deceleration feedback control. The indicated energization amount Ir is determined to increase as the target deceleration Gt increases according to the calculation map Zir. A predetermined upper limit value ro (preset constant) is set in the indicated energization amount Ir.

Similar to the first processing example, the target deceleration Gt and the deviation hG (= Gt-Ge) of the actual deceleration Ge are calculated. The compensation energization amount calculation block IG calculates the compensation energization amount Ig (one of the target values of the energization amount) based on the deceleration deviation hG. According to the calculation map Zig, when the deviation hG is in the range from the value −ho to the value ho (that is, the range of the dead zone), the compensation energization amount Ig is determined to be “0”. When the deviation hG is equal to or less than a predetermined value −ho, the compensating energization amount Ig is increased toward “0” with an increasing gradient Kc (variable value) as the deviation hG increases. When the deviation hG is equal to or greater than the predetermined value ho, the compensating energization amount Ig is increased from "0" at the increasing gradient Kc as the deviation hG increases. The predetermined value ho is a constant set in advance so as to form a dead zone of control.

The compensation energization amount calculation block IG corresponds to the deceleration feedback control. In the second calculation processing example, the direct control target of the deceleration feedback control is the amount of electricity supplied to the pressure regulating valve UP. The increasing gradient Kc in the arithmetic map Zig is the control gain (proportional gain) in the deceleration feedback control. In the calculation of the compensated energization amount Ig, the differential element of the deviation hG (the differential value of the deviation hG multiplied by the differential gain) and the integral element of the deviation hG (the integral value of the deviation hG is multiplied by the integral gain). Any one of the) can be considered.

Hereinafter, the processing in the control gain adjustment block KC, the target energization amount calculation block IT, and the drive circuit DR is the same as in the first calculation processing example. In the control gain adjustment block KC, the control gain Kc is determined based on the anti-skid control operation flags Fa, Fm, and the friction coefficient Mu. In the target energization amount calculation block IT, the target value (target energization amount) It of the final energization amount is calculated based on the indicated energization amount Ir and the compensated energization amount Ig. For example, the target energization amount It is determined by adding the indicated energization amount Ir and the compensated energization amount Ig. In the drive circuit DR, the energization amount feedback control of the pressure regulating valve UP is executed based on the target energization amount It. That is, the drive circuit DR performs the energization amount feedback control so that the actual energization amount (detected value of the energization amount sensor IA) Ia to the pressure regulating valve UP matches the target energization amount It.

<Processing of control gain adjustment block KC>
The processing of the automatic braking control (particularly, the control gain adjustment block KC) will be described with reference to the control flow diagram of FIG. In the control gain adjustment block KC, the control gain Kc of the deceleration feedback control is determined. The process is programmed in the braking controller ECU.

In step S110, the required deceleration Gr, the wheel speed Vw, the braking operation amount Ba, the front-rear acceleration Gx, the operation flags Fa, Fm, and the road surface friction coefficient Mu are read. The required deceleration Gr is calculated by the driving support controller ECJ and transmitted to the braking controller ECU through the communication bus BS. The wheel speed Vw, the braking operation amount Ba, and the front-rear acceleration (front-rear deceleration) Gx are detected by the wheel speed sensor VW, the braking operation amount sensor BA, and the front-rear acceleration sensor GX, and are input to the controller ECU. The operation flags Fa, Fm, and the road surface friction coefficient Mu are calculated by the anti-skid control block AC in the controller ECU. As the road surface friction coefficient Mu, one calculated by another controller or the like by a known method can be used.

In step S120, the target deceleration Gt is calculated based on the required deceleration Gr and the indicated deceleration Gs (see the process of the target deceleration calculation block GT). In step S130, the actual deceleration Ge is calculated based on at least one of the vehicle body speed Vx and the front-rear acceleration Gx (see the process of the actual deceleration calculation block GE). In step S140, the deviation hG (= Gt-Ge) of the target deceleration Gt and the actual deceleration Ge is calculated (see the process of the automatic braking control block JC).

In step S150, the control gain Kc is set to a predetermined value ko. Here, the predetermined value ko is an initial value (nominal value) corresponding to the case where the anti-skid control is not executed. The initial value ko is a preset constant with a relatively large value.

In step S160, "whether or not anti-skid control is being executed" is determined based on the operation flag Fa. The operation flag Fa is an operation flag calculated by the anti-skid control block AC. If "Fa = 0" and the anti-skid control is not executed, step S160 is denied and the process proceeds to step S200. On the other hand, when "Fa = 1" and the anti-skid control is executed, step S160 is affirmed, and the process proceeds to step S170.

In step S170, "whether or not the recovery condition of the control gain Kc is satisfied" is determined based on the operation flag Fm, the target deceleration Gt, and the friction coefficient Mu. When the anti-skid control is executed, the control gain Kc is reduced from the initial value ko. If the recovery conditions are satisfied, the reduced control gain Kc is increased. Details of the recovery conditions will be described later. If the recovery condition is not satisfied and step S170 is denied, the process proceeds to step S180. On the other hand, if the recovery condition is satisfied and step S170 is affirmed, the process proceeds to step S190.

In step S180, the control gain Kc is set to the first predetermined value km. The first predetermined value km is a preset constant corresponding to the case where the anti-skid control is executed. The predetermined value km is a relatively small value as compared with the initial value ko. For example, the predetermined value km can be set to "0". In the case of "km = 0", the deceleration feedback control is prohibited and is not executed (that is, it becomes an open loop control).

In step S190, the control gain Kc is set to the second predetermined value kn. The second predetermined value kn is also a preset constant corresponding to the case where the anti-skid control is executed. The second predetermined value kn is equal to or less than the initial value ko, but is a relatively large value as compared with the first predetermined value km. That is, each control gain has a relationship of “km <kn ≦ ko”. For example, the second predetermined value kn can be set equal to the nominal value (initial value) ko. In the case of "kn = ko", even if the anti-skid control is executed, the deceleration feedback control is executed in the same manner as when the anti-skid control is not executed.

In step S200, deceleration feedback control is executed based on the set control gain Kc (see processing of the automatic braking control block JC). Specifically, the compensating hydraulic pressure Ph is calculated based on the deceleration deviation hG and the control gain Kc. Finally, the target energization amount It is calculated based on the compensating hydraulic pressure Ph, and the pressure regulating valve UP is controlled so that the actual energization amount Ia approaches the target energization amount It (see FIG. 3). Further, the compensated energization amount Ig is calculated based on the deviation hG and the control gain Kc. The target energization amount It is determined based on the compensated energization amount Ig, and the pressure regulating valve UP is controlled so that the actual energization amount Ia approaches the target energization amount It (see FIG. 4).

≪Recovery conditions≫
The recovery conditions in step S170 will be described.
In order to suppress mutual interference between the automatic braking control and the anti-skid control, when the anti-skid control is executed, the control gain Kc of the feedback control of the automatic braking control is the first from the normal nominal value ko. It is reduced to a predetermined value km. The effectiveness of the deceleration feedback control is reduced and control interference is avoided, but the control accuracy is reduced. When the execution of the anti-skid control is completed, the control gain Kc is returned to the original nominal value ko. While the anti-skid control is being executed, it is determined that "the grip of the wheel WH is restored and the wheel slip is being restored" depending on the recovery condition. This is based on the fact that when the wheel slip starts to decrease, control interference is unlikely to occur even if the control gain Kc is increased from the first predetermined value km.

In the propriety determination according to the recovery condition, based on the operation flag Fm, "all the control modes of the four wheels WH are in the increase mode Mz state (four wheel increase mode state), and the duration Tk of that state is predetermined. Whether or not the time is tk or more "is determined. Here, the predetermined time (threshold value) tk is a preset constant (predetermined value) for determining whether or not the possibility is possible. The condition is referred to as a "reference condition" of the recovery condition.

Under the reference condition, when at least one of the four wheel WHs is in the reduction mode Mg (when "Fm = 0"), the recovery condition is denied. Further, even in the case of the increase mode Mz of all the wheels WH (in the case of "Fm = 1"), if the duration Tk of the four-wheel increase mode state is less than the predetermined time tk, the recovery condition is It is denied. The duration Tk is counted by the timer starting from the time when the four-wheel increase mode state is determined for the first time (the corresponding calculation cycle and the time when the operation flag Fm transitions from "0" to "1"). .. If the four-wheel increase mode state is denied (that is, when the operation flag Fm is changed from "1" to "0") before the duration Tk reaches the predetermined time tk, the duration Tk is ". It is returned to "0".

In addition to the above criteria, the following conditions are taken into consideration in determining whether or not the recovery conditions are acceptable.
Condition 1: Whether or not the road surface friction coefficient Mu is equal to or greater than the predetermined coefficient mu. Here, the predetermined coefficient (predetermined value) mu is a preset constant for determination.
When the above reference condition is satisfied, the recovery condition is affirmed if the friction coefficient Mu is equal to or more than the predetermined value mu. However, even if the reference condition is satisfied, if the friction coefficient Mu is less than the predetermined value mu, the recovery condition is denied. This is because when the road friction coefficient Mu is low, there is a high possibility that the grip will be lost again even in a situation where the grip of the wheel WH is being restored. As the friction coefficient Mu, a friction coefficient Mu calculated by another controller can be used in addition to the one calculated by the anti-skid control block AC.

Condition 2: Whether or not the target deceleration Gt is equal to or greater than the predetermined deceleration gt. Here, the predetermined deceleration gt is a preset constant for determination.
When the above reference condition is satisfied, the recovery condition is affirmed if the target deceleration Gt is equal to or greater than the predetermined deceleration gt. However, even if the reference condition is satisfied, if the target deceleration Gt is less than the predetermined deceleration gt, the recovery condition is denied. When the target deceleration Gt is relatively small, the effect of the deceleration feedback control is less likely to be required. In this case, the control interference can be reliably suppressed by keeping the control gain Kc at the first predetermined value km.

At least one of condition 1 and condition 2 may be omitted. That is, as the recovery conditions in step S170, among the four conditions of "reference condition only", "reference condition + condition 1", "reference condition + condition 2", and "reference condition + condition 1 + condition 2", Any one is adopted.

In normal automatic braking control, "Kc = ko" is set, and deceleration feedback control is executed so that the actual deceleration Ge approaches the target deceleration Gt. When the anti-skid control is executed, "Kc = km (<ko)" is set, and the control gain Kc is reduced (or set to "0"). This reduces the effectiveness of the deceleration feedback control (or prohibits the deceleration feedback control). As a result, the interference between the anti-skid control and the automatic braking control can be suppressed.

Further, recovery conditions are set based on the wheel WH increase mode Mz. When the recovery condition is satisfied, the control gain Kc is increased from the first predetermined value km to the second predetermined value kn (≦ ko). As a result, the effectiveness of the deceleration feedback control is increased, and the control accuracy of the automatic braking control is improved (or restored). In order to smoothly change (increase) the effectiveness of the feedback control, the control gain Kc changes from the first predetermined value km to the second predetermined value kn from the time when the recovery condition is satisfied for the first time (calculation cycle). The amount of change over time is limited to a predetermined value and can be gradually increased.

<Second Embodiment of Braking Control Device SC>
A second embodiment of the vehicle braking control device SC will be described with reference to the schematic diagram of FIG. In the second embodiment, the braking control device SC is a so-called brake-by-wire type. Anti-skid control is achieved by the solenoid valves VI, VO of the fluid unit HU, while automatic braking control is achieved by the electric motor (pressure regulating motor) ME of the pressure regulating unit YC.

As described above, the components, arithmetic processing, signals, characteristics, and values with the same symbol have the same function. In the subscripts "i" to "l" at the end of each symbol, "i" indicates the right front wheel, "j" indicates the left front wheel, "k" indicates the right rear wheel, and "l" indicates the left rear wheel. The subscripts "i" to "l" at the end of the symbol may be omitted. In this case, each symbol represents a generic term for each of the four wheels. In addition, the subscripts "1" and "2" at the end of each symbol indicate, in the two braking systems, "1" indicates the first system and "2" indicates the second system. The subscripts "1" and "2" at the end of the symbol may be omitted. In this case, each symbol represents a generic term for each of the two braking systems.

The braking control device SC includes a master cylinder valve VM, a simulator valve VS, a simulator SS, a master cylinder hydraulic pressure sensor PM, a fluid unit HU, a pressure regulating unit YC, and an adjusting hydraulic pressure sensor PF.
A master cylinder valve VM is provided in the master cylinder fluid passage HM connected to the master cylinder CM. The master cylinder valve VM is a normally open type on / off solenoid valve. At the time of braking, the master cylinder valve VM is closed and the connection between the master cylinder CM and the wheel cylinder CW is cut off.

A simulator SS is provided so as to generate an operating force Fp on the braking operation member BP during braking. Further, a simulator valve VS is provided so that the brake fluid BF is not consumed in the simulator SS when the braking control device SC is out of order. The simulator valve VS is a normally closed on / off solenoid valve. At the time of braking, the simulator valve VS is set to the open position, and the master cylinder CM and the simulator SS are in a communicating state. A master cylinder hydraulic pressure sensor PM is provided so as to detect the hydraulic pressure Pm of the master cylinder CM. The master cylinder hydraulic pressure sensor PM is one of the braking operation amount sensors BA. The master cylinder fluid passage HM is connected to the fluid unit HU as in the first embodiment. The fluid unit HU includes an inlet valve VI, an outlet valve VO, and an electric motor ML. These perform anti-skid control.

A pressure adjusting unit YC is provided so as to adjust the adjusted hydraulic pressure Pf (= Pw) instead of the hydraulic pressure Pm from the master cylinder CM by the driver. The pressure regulating unit YC is called a so-called "electric cylinder". The pressure control unit YC is an electric motor ME for pressure control, a speed reducer GN, a rotation / linear motion conversion mechanism (screw mechanism) NJ, a pressing member PO, a pressure control cylinder CE, a pressure control piston PE, and a return spring SE. It is composed.
The electric motor (pressure adjusting motor) ME is a power source for adjusting (increasing or decreasing) the braking fluid pressure Pw by the pressure adjusting unit YC. The pressure regulating motor ME is driven by the controller ECU. For example, a brushless motor may be adopted as the pressure adjusting motor ME.

The speed reducer GN is composed of a small diameter gear SK and a large diameter gear DK. The rotary power of the electric motor ME is decelerated by the speed reducer GN and transmitted to the screw mechanism NJ. In the screw mechanism NJ, the rotational power of the speed reducer GN is converted into the linear power of the pressing member PO. A nut member NT is fixed to the pressing member PO. The bolt member BT of the screw mechanism NJ is fixed coaxially with the large-diameter gear DK. Since the rotational movement of the nut member NT is constrained by the key member KY, the rotation of the large-diameter gear DK causes the nut member NT screwed with the bolt member BT to move in the direction of the rotation axis of the large-diameter gear DK. The pressure adjusting piston PE is moved by the pressing member PO. The pressure adjusting piston PE is inserted into the inner hole of the pressure adjusting cylinder CE to form a combination of the piston and the cylinder. A hydraulic chamber (pressure regulating cylinder chamber) Re partitioned by the pressure regulating cylinder CE and the pressure regulating piston PE is formed. A return spring (compression spring) SE is provided in the pressure regulating cylinder chamber Re. A stopper portion Sq is provided inside the pressure adjusting cylinder CE, and when the output of the pressure adjusting motor ME is "0", the pressure adjusting piston PE is pressed to a position where it abuts on the stopper portion Sq by the return spring SE.

The pressure adjusting cylinder chamber Re is connected to the pressure adjusting fluid path HE. The pressure regulating fluid passage HE is connected to the master cylinder fluid passage HM at the downstream portion of the master cylinder valve VM. By moving the pressure adjusting piston PE in the direction of the central axis, the volume of the pressure adjusting cylinder chamber Re changes, and the adjusting hydraulic pressure Pf is adjusted. Specifically, when the pressure adjusting motor ME is rotationally driven in the forward rotation direction, the pressure adjusting piston PE is moved in the forward direction He, and the adjusting hydraulic pressure Pf is increased. On the other hand, when the pressure adjusting motor ME is rotationally driven in the reverse direction, the pressure adjusting piston PE is moved in the backward direction Hg, and the adjusting hydraulic pressure Pf is reduced. The adjusting hydraulic pressure Pf is adjusted (increased or decreased) by adjusting the amount of electricity supplied to the pressure adjusting motor ME. An adjusting hydraulic pressure sensor PF is provided in the pressure adjusting fluid passage HE so as to detect the adjusting hydraulic pressure Pf.

By increasing or decreasing the adjusted hydraulic pressure Pf, the braking hydraulic pressure Pw is increased or decreased, and the braking torque Tq of the wheel WH is increased or decreased (adjusted). When the adjusting hydraulic pressure Pf is increased, the force with which the friction material is pressed against the rotating member KT is increased, and the braking torque Tq is increased. As a result, the braking force of the wheel WH is increased. On the other hand, when the adjusting hydraulic pressure Pf is reduced, the pressing force of the friction material against the rotating member KT is reduced, and the braking torque Tq is reduced. As a result, the braking force of the wheel WH is reduced.

In the second embodiment, the automatic braking control is realized by the pressure regulating unit YC. That is, the fluid unit HU is not used for automatic braking control. Therefore, in the second embodiment, the output hydraulic pressure Pf of the pressure regulating unit YC is directly controlled by the deceleration feedback control. In this case, the target value of the adjusted hydraulic pressure Pf is determined based on the calculation map including the deceleration deviation hG and the control gain Kc, as in the first processing example of the automatic braking control block JC. Then, feedback control is executed so that the adjusted hydraulic pressure Pf (detected value of the adjusted hydraulic pressure sensor PF) matches the target value.

The amount of electricity supplied to the electric motor ME (supply current) is roughly proportional to the output of the electric motor ME. Therefore, the amount of electricity supplied to the electric motor ME can be directly controlled by the deceleration feedback control. In this case, the target energization amount to the electric motor ME is determined based on the calculation map including the deceleration deviation hG and the control gain Kc, as in the second processing example of the automatic braking control block JC. Then, feedback control is executed so that the actual energization amount of the electric motor ME matches the target energization amount.

The second embodiment also has the same effect as the first embodiment. The control gain Kc is appropriately adjusted based on the operation flags Fa, Fm, the friction coefficient Mu, and the target deceleration Gt. As a result, mutual interference between the automatic braking control and the anti-skid control can be suppressed. In addition, when the deceleration slip is heading for recovery, the control gain Kc is increased based on the recovery conditions before the anti-skid control is terminated. As a result, the effectiveness of the feedback control can be appropriately adjusted, and the control accuracy of the automatic braking control can be ensured.

<Third Embodiment of the braking control device SC>
A third embodiment of the vehicle braking control device SC will be described with reference to FIG. 7. In the first and second embodiments, the braking fluid pressure Pw was used for adjusting the braking torque Tq. In the third embodiment, no fluid is used to adjust the braking torque Tq. Therefore, the anti-skid control and the automatic braking control are realized by adjusting the rotation direction and the output of the electric motor MT. The configuration is referred to as a so-called "EMB (electromechanical air brake)".

The braking control device SC according to the third embodiment includes an electric motor MT, a speed reducer GN, a screw mechanism NJ, a pressing piston PN, and a pressing pressure sensor FB. The brake control device SC is formed in the brake caliper CP. A braking control device SC is provided in place of the wheel cylinder CW in the first and second embodiments.
The electric motor (wheel motor) MT is a power source for adjusting (increasing or decreasing) the force Fb that the friction member MS presses on the rotating member KT. The electric motor MT is driven by the controller ECU. For example, a brushless motor may be adopted as the electric motor MT.

The speed reducer GN is composed of a small diameter gear SK and a large diameter gear DK. The rotary power of the electric motor MT is decelerated by the speed reducer GN and transmitted to the screw mechanism NJ. The rotational power of the speed reducer GN is converted into the linear power of the pressing piston PN by the screw mechanism NJ. A nut member NT is fixed to the pressing piston PN. The bolt member BT of the screw mechanism NJ is fixed coaxially with the large-diameter gear DK. Since the rotational movement of the nut member NT is constrained by the key member KY, the rotation of the large-diameter gear DK causes the nut member NT screwed with the bolt member BT to move in the direction of the rotation axis of the large-diameter gear DK, and the pressing piston. The relative distance between the PN and the rotating member KT is adjusted.

The friction member MS is fixed to the pressing piston PN. The braking torque Tq is adjusted by adjusting the rotation direction and output of the electric motor MT. When the electric motor MT is rotationally driven in the forward rotation direction, the pressing piston PN is moved in the forward direction He, and the force Fb at which the friction member MS presses the rotating member KT is increased. By increasing the pressing force Fb, the braking torque Tq is increased and the braking force of the wheel WH is increased. On the other hand, when the electric motor MT is rotationally driven in the reverse direction, the pressing piston PN is moved in the backward direction Hg, and the pressing force Fb is reduced. By reducing the pressing force Fb, the braking torque Tq is reduced and the braking force of the wheel WH is reduced. The braking control device SC is provided with a pressing force sensor FB so as to detect the pressing force Fb.

The pressing force Fb is directly controlled by the deceleration feedback control. In this case, the target value (target pressing force) corresponding to the pressing force Fb is determined based on the calculation map including the deceleration deviation hG and the control gain Kc. Then, feedback control is executed so that the pressing force Fb (detected value of the pressing force sensor FB) matches the target pressing force.

The amount of electricity supplied to the electric motor MT (supply current) is roughly proportional to the output of the electric motor MT. Therefore, the amount of electricity supplied to the electric motor MT can be directly controlled by the deceleration feedback control. In this case, the target energization amount to the electric motor MT is determined based on the calculation map including the deceleration deviation hG and the control gain Kc. Then, feedback control is executed so that the actual energization amount of the electric motor MT matches the target energization amount.

The third embodiment also has the same effect as the first and second embodiments. Control interference can be suppressed by appropriately adjusting the control gain Kc. When the wheel grip tends to recover, the effectiveness of the feedback control can be appropriately adjusted by increasing the control gain Kc before the anti-skid control is terminated.

<Action / effect>
The actions and effects of the braking control device SC according to the present invention will be summarized below.
The braking torque Tq is applied to the wheel WH by the braking control device SC. In the controller ECU of the braking control device SC, automatic braking control for adjusting the braking torque Tq is executed based on the deceleration target value Gt determined according to the relative distance Ob between the object in front of the vehicle and the vehicle. In the automatic braking control, the deceleration actual value Ge corresponding to the deceleration target value Gt is calculated. Then, based on the deceleration target value Gt and the deceleration actual value Ge, feedback control (processing of the calculation block PH and IG) is executed so that the deceleration actual value Ge approaches the deceleration target value Gt. That is, the braking torque Tq is adjusted so that the deceleration target value Gt is achieved by the feedback control related to the deceleration of the vehicle.

Further, in the controller ECU, anti-skid control is executed in which the braking torque Tq is adjusted based on the speed Vw of the wheel WH to suppress an excessive slip Sw of the wheel WH. When the anti-skid control is executed (that is, when "Fa = 1"), the control gain Kc of the feedback control is reduced. For example, when the anti-skid control is executed, the control gain Kc is adjusted to "0", and the execution of the feedback control is prohibited. That is, the automatic braking control is changed to open loop control. In the automatic braking control, the effectiveness of the feedback control is adjusted by the control gain Kc. During the execution of the anti-skid control, the control gain Kc is reduced from the initial value ko to the first predetermined value km, and its effectiveness is weakened. Therefore, mutual interference between the two controls can be suppressed.

In the controller ECU, in the anti-skid control, either the decrease mode Mg that reduces the braking torque Tq or the increase mode Mz that increases the braking torque Tq is determined based on the speed Vw. In the situation where the control gain Kc of the feedback control is decreased, the control gain Kc is increased when the time Tk in which the increase mode Mz continues to be determined for all of the wheel WH exceeds the threshold time tk. For example, the control gain Kc is returned to the non-execution value (initial value ko) of the anti-skid control. When the above condition (recovery condition) is satisfied, the wheel grip tends to recover and control interference is unlikely to occur. Therefore, the control gain Kc is increased, and the effectiveness of the automatic braking control can be strengthened.

It is determined whether or not the road surface friction coefficient Mu is equal to or greater than the predetermined value mu, and when “Mu ≧ mu”, an increase in the control gain Kc is permitted. On the other hand, in the case of "Mu <mu", the increase of the control gain Kc is prohibited. When the road friction coefficient Mu is low, the wheel grip is likely to be lost, and the control gain Kc may be repeatedly increased or decreased. In order to avoid the complexity of control, the control gain Kc can be increased only when the friction coefficient Mu is a predetermined value mu or more.

It is determined whether or not the target deceleration Gt is equal to or greater than the predetermined acceleration gt, and when “Gt ≧ gt”, the increase in the control gain Kc is permitted. On the other hand, in the case of "Gt <gt", the increase of the control gain Kc is prohibited. When the target deceleration Gt is small, the effectiveness of the deceleration feedback control is not required so much. In this case, in consideration of the complexity of control, the control gain Kc is kept reduced to the first predetermined value km and is not increased.

The control gain Kc can be gradually changed (corrected) in at least one of the case where the control gain Kc is decreased and the case where the control gain Kc is increased. For example, the decreasing gradient of the control gain Kc is limited to a preset predetermined gradient (predetermined value) kg. Further, the increasing gradient of the control gain Kc is limited to a preset predetermined gradient (predetermined value) kz. As a result, smooth gain adjustment can be performed in the feedback control of the automatic braking control.

<Other embodiments>
Hereinafter, other embodiments will be described. In other embodiments, the same effect as described above is obtained.
In the above embodiment, a linear type pressure regulating valve UP whose valve opening amount is adjusted according to the energization amount is adopted. For example, the pressure regulating valve UP is an on / off valve (two-position switching type solenoid valve), but the opening / closing of the valve may be controlled by the duty ratio and the hydraulic pressure may be controlled linearly.

In the above embodiment, the required value (required deceleration Gr) is transmitted from the driving support controller ECJ to the braking controller ECU in the dimension of acceleration. Instead, the requested value may be transmitted in the velocity dimension. Specifically, the operation support controller ECJ calculates the required speed Vr, which is transmitted via the communication bus BS. In the braking controller ECU, the required speed Vr can be converted into acceleration specifications, and the required deceleration Gr can be calculated.

The driving support controller ECJ and the braking controller ECU can be integrated. In this case, the processing of the controller ECJ is included in the controller ECU, and the relative distance sensor OB is connected to the controller ECU.

In the above embodiment, the configuration of the disc type braking device (disc brake) has been exemplified. In this case, the friction member is a brake pad and the rotating member is a brake disc. A drum type braking device (drum brake) may be adopted instead of the disc type braking device. In the case of drum brakes, brake drums are used instead of calipers. The friction member is a brake shoe, and the rotating member is a brake drum.

In the above embodiment, a diagonal type fluid path is exemplified as the two-system fluid path. Instead of this, a front-rear type (also referred to as "H type") configuration may be adopted. In the front-rear type fluid path, the front wheel wheel cylinders CWi and CWj are fluidly connected to the first master cylinder fluid path HM1 (that is, the first system). Further, the second master cylinder fluid path HM2 (that is, the second system) is fluidly connected to the rear wheel cylinders CWk and CWl.

BP ... Braking operation member, BF ... Braking liquid, CM ... Master cylinder, CW ... Wheel cylinder, UP ... Pressure regulating valve, VI ... Inlet valve, VO ... Outlet valve, ML ... Electric motor (recirculation motor), ME ... Electric motor ( Pressure regulation motor), MT ... Electric motor (wheel motor), QL ... Fluid pump, ECU ... Controller, Kc ... Control gain.

Claims (2)

A vehicle braking control device that applies braking torque to the wheels of a vehicle.
Automatic braking control for adjusting the braking torque is executed based on the deceleration target value of the vehicle according to the distance between the object in front of the vehicle and the vehicle.
It comprises a controller that adjusts the braking torque based on the speed of the wheel to perform anti- skid control.
The controller
Calculate the actual deceleration value corresponding to the deceleration target value,
Based on the deceleration target value and the deceleration actual value, feedback control is executed so that the deceleration actual value approaches the deceleration target value.
When the anti-skid control is performed, it is configured to reduce the control gain of the feedback control .
The controller
In the anti-skid control, when either the decrease mode for reducing the braking torque or the increase mode for increasing the braking torque is determined based on the speed and the control gain is reduced. In addition, a vehicle braking control device that increases the control gain when the state in which the increase mode is determined for all of the wheels is continued for a predetermined time . A vehicle braking control device that applies braking torque to the wheels of a vehicle.
Automatic braking control for adjusting the braking torque is executed based on the deceleration target value of the vehicle according to the distance between the object in front of the vehicle and the vehicle.
It comprises a controller that adjusts the braking torque based on the speed of the wheel to perform anti- skid control.
The controller
Calculate the actual deceleration value corresponding to the deceleration target value,
Based on the deceleration target value and the deceleration actual value, feedback control is executed so that the deceleration actual value approaches the deceleration target value.
When the anti-skid control is executed, it is configured to prohibit the execution of the feedback control.
The controller
In the anti-skid control, one of a decrease mode for reducing the braking torque and an increase mode for increasing the braking torque is determined based on the speed, and the feedback control is prohibited. In addition, a vehicle braking control device that resumes execution of the feedback control when the state in which the increase mode is determined for all of the wheels is continued for a predetermined time .

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