JP6301706B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake control device, and more particularly, to brake control corresponding to a split road in which a friction coefficient of a ground road surface is greatly different on the left and right.

  Conventionally, as a vehicle brake control device capable of executing brake control corresponding to a split road, the right yaw rate is detected so that the actual yaw rate detected by the yaw rate sensor approaches the target yaw rate set based on the steering angle and the vehicle speed. What sets the difference of the brake fluid pressure concerning a wheel brake is known (refer to patent documents 1).

JP 2013-132973 A

  However, since the conventional technology is control based on the yaw rate, the direction of the vehicle with respect to the traveling direction of the vehicle may vary, and the driver's operation feeling may be impaired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle brake control device that can improve a driver's operation feeling on a split road.

  In order to solve the above-described problem, a vehicle brake control device according to the present invention includes a slip angle acquisition unit that acquires a slip angle that is an angle formed by a traveling direction of a vehicle and a direction of the vehicle, and a friction coefficient of a ground contact surface of a wheel. Braking force difference setting means for setting a difference between the braking force of the wheel brake on the high friction coefficient side and the braking force of the wheel brake on the low friction coefficient side on split roads that differ from each other by a predetermined amount on the left and right, and the braking force The difference setting means sets the difference in the braking force so that the slip angle follows the target slip angle.

  According to this configuration, by controlling the difference in braking force so that the slip angle follows the target slip angle, it becomes possible to control the vehicle in consideration of the direction of the vehicle. Can be suppressed, and the operational feeling can be improved.

  In the above-described configuration, the target slip angle can be set to an angle such that the direction of the vehicle faces the road surface on the high friction coefficient side with respect to the traveling direction.

  According to this, on the split road, since the direction of the vehicle is controlled so as to face the road surface on the high friction coefficient side with respect to the traveling direction, the driver is prompted to correct the rudder to correct the posture of the vehicle. it can. Further, since the slip angle can be brought close to the target slip angle by the modified rudder, the difference in braking force can be increased, and a sufficient braking force can be ensured.

  In the above configuration, the target slip angle may be set in advance corresponding to an elapsed time from the time when the setting of the braking force difference is started by the braking force difference setting unit.

  According to this, since the target slip angle is determined in accordance with the elapsed time from the time when the setting of the difference in braking force is started, it is possible to further suppress variation in the vehicle direction with respect to the traveling direction of the vehicle.

  In addition, in the above configuration, when the target slip angle setting means for setting the target slip angle based on at least the steering angle is provided, the target slip angle setting means directs the vehicle toward the road surface on the low friction coefficient side. When the steering angle by such steering is positive, if the steering angle is positive, the target slip angle is set to be smaller as the steering angle increases, and if the steering angle is 0 or less, the target The slip angle can be set to a constant value equal to or greater than the value when the steering angle is positive.

  According to this, for example, when the steering angle is close to 0, the target slip angle becomes a large value, and the direction of the vehicle faces the road surface on the high friction coefficient side, so that the driver can be prompted to correct the rudder.

  In the above configuration, when the target slip angle setting means for setting the target slip angle based on at least the vehicle speed is provided, the target slip angle setting means can be configured such that the target slip angle increases as the vehicle speed increases. The corner can be set to be small.

  According to this, when the vehicle speed is high, the direction of the vehicle can be brought close to the traveling direction, so that the posture of the vehicle can be stabilized.

  Further, in the above configuration, when the target slip angle setting means for setting the target slip angle based on the steering angle and the vehicle speed is provided, the target slip angle setting means is calculated based on the steering angle. A smaller value of the target slip angle and the target slip angle calculated based on the vehicle speed can be set as the target slip angle.

  According to this, it is possible to satisfactorily set the target slip angle based on the steering angle and the vehicle speed.

  In the above configuration, the braking force difference setting means calculates a first braking force difference based on a deviation between the slip angle and the target slip angle, and based on a steering angle, the second braking force difference is calculated. And the difference between the braking forces can be set by adding the first braking force difference and the second braking force difference.

  According to this, since the difference in braking force is calculated based on the slip angle, the target slip angle, and the steering angle, the difference in braking force can be set with high accuracy.

  Further, in the above-described configuration, the target slip angle setting means can converge the target slip angle toward 0 when the difference in braking force becomes a predetermined value or more.

  According to this, when the difference between the left and right braking forces becomes large, that is, when the braking force is sufficiently secured, the target slip angle becomes small, so that the direction of the vehicle can be made closer to the traveling direction, and the attitude of the vehicle Can be stabilized.

  ADVANTAGE OF THE INVENTION According to this invention, a driver | operator's operation feeling can be improved in a split road.

It is a lineblock diagram of vehicles provided with a brake control device for vehicles concerning an embodiment. It is a block diagram which shows the structure of a hydraulic unit. It is a block diagram which shows the structure of a control part. It is a map which shows the relationship between the vehicle speed for setting a target slip angle, and the target slip angle based on a vehicle speed. It is a map which shows the relationship between the steering angle for setting a target slip angle, and the target slip angle based on a steering angle. It is a block diagram which shows the structure of a differential pressure setting means. It is a map which shows the relationship between the steering angle for setting a feedforward differential pressure, and the differential pressure based on a steering angle. It is a map which shows the relationship between vehicle speed and differential pressure for setting differential pressure. It is a flowchart which shows the process at the time of antilock brake control by a control part. It is a timing chart which shows change of a steering angle, a slip angle, and differential pressure.

Next, embodiments will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the vehicle brake control device A according to the present embodiment is a device that appropriately controls the braking force applied to each wheel W of the vehicle CR. The vehicle brake control device A mainly includes a hydraulic unit 10 provided with an oil passage and various parts, and a control unit 100 for appropriately controlling various parts in the hydraulic unit 10.

  Each wheel W is provided with a wheel brake FL, RR, RL, FR, and each wheel brake FL, RR, RL, FR is braked by a hydraulic pressure supplied from a master cylinder MC as a hydraulic pressure source. Is provided. Master cylinder MC and wheel cylinder H are each connected to hydraulic unit 10. In normal times, the brake hydraulic pressure generated in the master cylinder MC in response to the depression force of the brake pedal BP (driver's braking operation) is supplied to the wheel cylinder H after being controlled by the control unit 100 and the hydraulic unit 10. Is done.

  The control unit 100 includes a pressure sensor 91 that detects the pressure of the master cylinder MC, a wheel speed sensor 92 that detects the wheel speed of each wheel W, a steering angle sensor 93 that detects the steering angle θ of the steering ST, and a vehicle. A yaw rate sensor 94 that detects an actual yaw rate Y that is an actual yaw rate of the CR is connected. The control unit 100 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an input / output circuit, and inputs from the sensors 91 to 94 and the ROM The control is executed by performing various arithmetic processes based on the programs and data stored in. Details of the control unit 100 will be described later.

  As shown in FIG. 2, the hydraulic unit 10 is disposed between the master cylinder MC and the wheel brakes FL, RR, RL, FR. The two output ports M1, M2 of the master cylinder MC are connected to the inlet port 10a of the hydraulic unit 10, and the outlet port 10b is connected to each wheel brake FL, RR, RL, FR. In normal times, the oil pressure path of the brake pedal BP is transmitted to the wheel brakes FL, RR, RL, and FR because the oil passage communicates from the inlet port 10a to the outlet port 10b in the hydraulic unit 10. It has become so.

  The hydraulic pressure unit 10 is provided with four inlet valves 1, four outlet valves 2, and four check valves 1a corresponding to the wheel brakes FL, RR, RL, FR. The hydraulic unit 10 is also provided with a reservoir 3, a pump 4, and an orifice 5a in each of the hydraulic pressure paths 11 and 12 corresponding to the output ports M1 and M2 of the master cylinder MC. The hydraulic unit 10 is provided with a common motor 6 for driving the pumps 4.

  The inlet valve 1 is a normally open proportional solenoid valve provided between each wheel brake FL, RR, RL, FR and the master cylinder MC. The inlet valve 1 is normally opened to allow the brake hydraulic pressure to be transmitted from the master cylinder MC to the wheel brakes FL, RR, RL, FR. In addition, the inlet valve 1 is blocked by the control unit 100 when the wheel W is about to be locked, thereby cutting off the hydraulic pressure transmitted from the brake pedal BP to each wheel brake FL, RR, RL, FR.

  The outlet valve 2 is a normally closed electromagnetic valve provided between each wheel brake FL, RR, RL, FR and the reservoir 3. Although the outlet valve 2 is normally closed, the hydraulic pressure applied to the wheel brakes FL, RR, RL, FR is applied to the reservoir 3 by being released by the control unit 100 when the wheel W is about to be locked. Let it go.

  The check valve 1a is connected to each inlet valve 1 in parallel. This check valve 1a is a valve that only allows the brake fluid to flow from the wheel brakes FL, RR, RL, FR side to the master cylinder MC side, and the inlet valve when the input from the brake pedal BP is released. Even when 1 is closed, the flow of brake fluid from each wheel brake FL, RR, RL, FR side to the master cylinder MC side is allowed.

The reservoir 3 has a function of temporarily storing brake fluid that is released when each outlet valve 2 is opened.
The pump 4 is provided between the reservoir 3 and the master cylinder MC, and has a function of sucking the brake fluid stored in the reservoir 3 and returning the brake fluid to the master cylinder MC through the orifice 5a. ing.

  The inlet valve 1 and the outlet valve 2 control the brake fluid pressure of the wheel cylinders H of the wheel brakes FL, RR, RL, FR by the control unit 100 controlling the open / close state. For example, in a normal state in which the inlet valve 1 is open and the outlet valve 2 is closed, if the brake pedal BP is depressed, the hydraulic pressure from the master cylinder MC is transmitted to the wheel cylinder H as it is, and the pressure increases. When the valve 1 is closed and the outlet valve 2 is opened, the brake fluid flows out from the wheel cylinder H to the reservoir 3 side to be in a reduced pressure state, and when both the inlet valve 1 and the outlet valve 2 are closed, the brake fluid pressure is increased. It becomes a holding state to be held.

Next, details of the control unit 100 will be described.
The control unit 100 is a device that performs control to stabilize the vehicle by controlling the hydraulic unit 10 and applying the braking force set to each wheel brake FL, RR, RL, FR. Therefore, as shown in FIG. 3, the control unit 100 includes a vehicle speed acquisition unit 111, a steering angle acquisition unit 112, an actual yaw rate acquisition unit 113, a target slip angle setting unit 121, and a slip angle acquisition unit 122. The anti-lock brake control means 130, the split road determination means 140, the differential pressure setting means 150 as an example of the braking force difference setting means, the control execution means 160, and the storage means 190 are mainly provided. Yes.

  The vehicle speed acquisition unit 111 is a unit that acquires information on the wheel speed WS (pulse signal of the wheel speed sensor 92) from the wheel speed sensor 92, and calculates and acquires the vehicle speed V by a known method. The calculated vehicle speed V is output to the target slip angle setting means 121, the antilock brake control means 130, and the differential pressure setting means 150.

  The steering angle acquisition unit 112 is a unit that acquires information on the steering angle θ from the steering angle sensor 93. The acquired steering angle θ is output to the target slip angle setting means 121 and the differential pressure setting means 150. In the present specification, the steering angle θ is positive when the steering ST is operated in the direction in which the vehicle CR turns to the low friction coefficient side on the split road.

  The actual yaw rate acquisition unit 113 is a unit that acquires information on the actual yaw rate Y that is the actual yaw rate of the vehicle CR from the yaw rate sensor 94. The acquired actual yaw rate Y is output to the slip angle acquiring means 122. In this specification, the actual yaw rate Y, the slip angle D and the target slip angle DT, which will be described later, are positive in the direction in which the vehicle CR turns to the high friction coefficient side on the split road.

  The target slip angle setting means 121 is a means for setting the target slip angle DT based on the vehicle speed V and the steering angle θ.

More specifically, the target slip angle setting means 121 calculates a target slip angle DT _V based on the vehicle speed V, and the target slip angle DT _theta based on the steering angle theta, the target slip angle DT _V, among DT _theta The smaller value is calculated as the target slip angle DT. FIG. 4 is a map for setting the target slip angle DT _V based on the vehicle speed V, and is determined so that the target slip angle DT _V decreases as the vehicle speed V increases. Specifically, the target slip angle DT _V is in a range of vehicle speed V may assume, is always a positive value, i.e. set at an angle so that the direction of the vehicle CR is facing high coefficient of friction road surface side to the traveling direction ing.

FIG. 5 is a map for setting the target slip angle DT _θ based on the steering angle θ, and is determined so that the target slip angle DT _θ decreases as the steering angle θ increases. Specifically, in the range where the steering angle θ is 0 or less, the target slip angle DT _θ is determined to be a constant value (a constant value equal to or greater than the value when the steering angle θ is positive), and the steering angle θ is from 0 to a predetermined value θ1. During this time, the target slip angle DT _θ decreases as the steering angle θ increases at a constant rate from the above-described constant value. When the steering angle θ is between the predetermined value θ1 and the predetermined value θ2, the range from 0 to the predetermined value θ1. The target slip angle DT _θ decreases as the steering angle θ increases with a larger reduction rate than in the case of the interval, and the target slip angle DT _θ is determined to be 0 in a range where the steering angle θ is larger than the predetermined value θ2. Yes. In other words, the target slip angle DT _θ is always a positive value when the steering angle is less than the predetermined value θ2, that is, an angle at which the direction of the vehicle CR faces the road surface on the high friction coefficient side with respect to the traveling direction. Is set to

Note that the target slip angle DT _V when the vehicle speed V in the map of FIG. 4 is 0 is set to a value smaller than the target slip angle DT _θ when the steering angle θ is 0 in the map of FIG.

  Further, when the target slip angle setting unit 121 receives information indicating that the road is a split road from the split road determination unit 140 described later, the target slip angle DT is set as described above, and the target slip angle DT is set. Is output to the differential pressure setting means 150.

  The slip angle acquisition unit 122 is a unit that acquires a slip angle D that is an angle formed by the traveling direction of the vehicle CR and the direction of the vehicle CR based on the actual yaw rate Y. Specifically, the slip angle D is calculated by integrating the value of the actual yaw rate Y. The acquired slip angle D is output to the differential pressure setting means 150.

  The anti-lock brake control means 130 determines, for each wheel W, whether or not to execute the anti-lock brake control by a known method based on the wheel speed WS and the vehicle speed V, and the liquid during the anti-lock brake control. This is means for determining for each wheel W an instruction for pressure control (instruction on whether to set the hydraulic pressure in the wheel cylinder H to the increased state, the held state, or the reduced state). Information indicating that the anti-lock brake control is to be executed is output to the split road determination unit 140, and the determined hydraulic pressure control instruction is output to the control execution unit 160.

  The split road determination means 140 is a means for determining whether or not the split road has a friction coefficient different from the left and right by a predetermined amount or more when the antilock brake control is executed. The method for determining the split road is not particularly limited. As an example, when the anti-lock brake control is executed, the wheel W indicating the maximum value (the value at which the deceleration is least) among the decelerations of the wheels W. Can be determined as a split road when the difference between the decelerations of the left and right wheels W is equal to or greater than the second threshold. Further, when the split road determination unit 140 determines that the road is a split road, the split road determination unit 140 determines which of the left and right wheels W is on the high friction coefficient side and which is on the low friction coefficient side. As an example, of the left and right wheels W, the wheel W having the smaller deceleration is determined as the high friction coefficient side, and the wheel W having the larger deceleration is determined as the low friction coefficient side. Information indicating that the road is a split road is output to the target slip angle setting means 121 and the differential pressure setting means 150.

  The differential pressure setting means 150 is a means for setting a braking force difference that is a difference between the braking force of the wheel brake on the high friction coefficient side and the braking force of the wheel brake on the low friction coefficient side on the split road. In this embodiment, the differential pressure setting means 150 is a difference between the brake fluid pressure of the wheel brake on the high friction coefficient side and the brake fluid pressure of the wheel brake on the low friction coefficient side as a value corresponding to the braking force difference. The differential pressure DP is set so that the slip angle D follows the target slip angle DT. For this control, as shown in FIG. 6, the differential pressure setting means 150 includes a feedforward differential pressure calculator 151, a deviation calculator 152, a feedback differential pressure calculator 153, and a differential pressure calculator 156. Have.

  Note that the calculation of the differential pressure by each of the calculation units 151 to 153 is not performed until a predetermined time T1 that has been set after the determination that the road is a split road, but is performed after the elapse of the predetermined time T1. It has become.

Feedforward pressure calculation unit 151, based on the steering angle theta, a means for calculating the feedforward differential pressure DP _FF. FIG. 7 is a map for setting the feedforward differential pressure DP _FF (second braking force difference for canceling slip angle fluctuation due to steering) based on the steering angle θ, and the differential pressure increases as the steering angle θ increases. It is decided to grow. The calculated feedforward differential pressure DP _FF is output to the differential pressure calculation unit 156.

  The deviation calculation unit 152 is a means for calculating a deviation ΔD (= D−DT) between the slip angle D and the target slip angle DT. The calculated deviation ΔD is output to the feedback differential pressure calculation unit 153.

The feedback differential pressure calculation unit 153 is means for calculating a feedback differential pressure DP _FB for setting the differential pressure DP by PID (Proportional Integral Derivative) control so that the slip angle D follows the target slip angle DT. Specifically, the feedback differential pressure DP _FB corresponds to the first braking force difference necessary to reduce the deviation ΔD between the slip angle D and the target slip angle DT, and is the P term (proportional gain × current deviation ΔD). And the I term (previous I term + (integral gain × current deviation ΔD)) and D term (differential gain × (previous deviation ΔD−current deviation ΔD)) are added. The calculated feedback differential pressure DP _FB is output to the differential pressure calculation unit 156.

The differential pressure calculation unit 156 is a means for calculating the differential pressure DP. Specifically, the differential pressure DP is calculated based on the vehicle speed V and a preset map until a predetermined time T1 elapses after it is determined that the road is a split road. FIG. 8 is a map for setting the differential pressure DP from when it is determined that the road is a split road until the predetermined time T1 elapses. The higher the vehicle speed V, the smaller the differential pressure DP. It has been decided. On the other hand, after a predetermined time T1 after it is determined that the split road is elapsed, it calculates the differential pressure DP based on the feedforward differential pressure DP _FF and the feedback differential pressure DP _FB. Specifically, the differential pressure DP is calculated by adding the feedforward differential pressure DP _FF and the feedback differential pressure DP _FB . The calculated differential pressure DP is output to the control execution means 160.

  Based on the hydraulic pressure control instruction determined by the anti-lock brake control means 130 and the differential pressure DP set by the differential pressure setting means 150, the control execution means 160 uses a known method to cause the wheel brakes FL, RR, RL, It is means for controlling the brake fluid pressure of FR. Specifically, for the wheel brake that executes the antilock brake control, the hydraulic pressure unit 10 is controlled based on the hydraulic pressure control instruction determined by the antilock brake control means 130. Also, when it is determined that the road is split, if the difference between the brake fluid pressure of the wheel brake on the high friction coefficient side and the brake fluid pressure of the wheel brake on the low friction coefficient side is likely to exceed the differential pressure DP The hydraulic pressure unit 10 is controlled such that the brake fluid pressure of the wheel brake on the high friction coefficient side becomes a value obtained by adding the differential pressure DP to the brake fluid pressure of the wheel brake on the low friction coefficient side. The specific control of the hydraulic unit 10 is well known and will not be described in detail. However, in brief, the current output to the inlet valve 1 and the outlet valve 2 is adjusted, and the motor 6 is turned on as necessary. It controls to drive and drive the pump 4.

  The storage unit 190 is a unit that appropriately stores programs, constants, maps, calculation results, and the like necessary for the operation of the control unit 100.

  Next, processing during antilock brake control by the control unit 100 of the vehicle brake control device A will be described with reference to FIG. Note that the process of FIG. 9 is repeated for each control cycle.

  First, the control unit 100 acquires the wheel speed WS from the wheel speed sensor 92, the steering angle θ from the steering angle sensor 93, and the actual yaw rate Y from the yaw rate sensor 94 (S101). Next, the control unit 100 calculates the vehicle speed V from the wheel speed WS, calculates the target slip angle DT based on the vehicle speed V and the steering angle θ, and calculates the slip angle D from the actual yaw rate Y (S102). ). Then, the antilock brake control means 130 determines a hydraulic pressure control instruction for the antilock brake control (S111).

Next, the split road determination unit 140 determines whether or not the ground road surface of the wheel W is a split road (S112).
When it is determined that the road is not a split road (S112, NO), the control execution means 160 controls the hydraulic pressure unit 10 based on the hydraulic pressure control instruction of the antilock brake control, and controls the brake hydraulic pressure of the wheel brake. (S131).

  If it is determined in step S112 that the road is a split road (YES), the differential pressure setting unit 150 determines whether or not a predetermined time T1 has elapsed since it was determined that the road is a split road (S121). When the predetermined time T1 has not elapsed (S121, NO), the differential pressure setting means 150 sets the differential pressure DP from the map of FIG. 8 based on the vehicle speed V (S122).

On the other hand, in step S121, when the predetermined time T1 has elapsed (YES), the differential pressure setting means 150 calculates the feedforward differential pressure DP _FF based on the steering angle θ (S124). Further, the differential pressure setting means 150 calculates a deviation ΔD between the slip angle D and the target slip angle DT (S125), and calculates a feedback differential pressure DP _FB by PID control based on the deviation ΔD (S126).

Then, the differential pressure setting means 150 calculates the sum of the feedforward differential pressure DP _FF and the feedback differential pressure DP _FB as the differential pressure DP (S127).

  When the differential pressure DP is calculated, the control execution means 160 controls the hydraulic pressure unit 10 based on the differential pressure DP and the hydraulic pressure control instruction of the antilock brake control, and controls the brake hydraulic pressure of the wheel brake. (S131). Specifically, the brake fluid pressure of the wheel brake on the low friction coefficient side is controlled based on the hydraulic control instruction of the anti-lock brake control, and the brake fluid pressure and the low friction coefficient of the wheel brake on the high friction coefficient side are controlled. If the difference from the brake fluid pressure of the wheel brake on the side is likely to exceed the differential pressure DP, the brake fluid pressure of the wheel brake on the high friction coefficient side becomes the differential pressure on the brake fluid pressure of the wheel brake on the low friction coefficient side. The brake fluid pressure of the wheel brake on the high friction coefficient side is controlled so as to be a value obtained by adding DP.

  The effect of the vehicle brake control device A of the present embodiment described above will be described with reference to FIG.

In FIG. 10, it is assumed that the brake pedal BP is depressed at time t11. Thereafter, the anti-lock brake control is started on the wheel on the low friction coefficient side, and it is determined that the road is split at time t12. After time t13, the differential pressure is determined based on the feedforward differential pressure DP _FF and the feedback differential pressure DP _FB. Calculated. That is, after time t13, the differential pressure is controlled so that the slip angle D follows the target slip angle DT.

  Specifically, when the split road determination unit 140 determines that the road is a split road at time t12, the target slip angle setting unit 121 outputs the target slip angle DT set at that time to the differential pressure setting unit 150. The means 150 sets the differential pressure based on the map of FIG. 8 without using the target slip angle DT during the predetermined time T1 from the time t12. After a predetermined time T1 has elapsed from time t12 (after time t13), the differential pressure setting means 150 sets the differential pressure so that the slip angle D follows the target slip angle DT set in advance at time t12. As a result, as shown in FIG. 10, the slip angle D gradually approaches the target slip angle DT after time t13.

According to the above, the following effects can be obtained in the present embodiment.
By controlling the differential pressure so that the slip angle D follows the target slip angle DT, it becomes possible to control the direction of the vehicle CR, so that variation in the direction of the vehicle CR with respect to the traveling direction of the vehicle CR is suppressed. And the operational feeling can be improved.

  By setting the target slip angle DT so that the direction of the vehicle CR faces the road surface on the high friction coefficient side with respect to the traveling direction, the direction of the vehicle CR on the split road is high with respect to the traveling direction. Therefore, the driver can be prompted to correct the rudder to correct the posture of the vehicle CR. Further, when the correction rudder becomes large, the differential pressure can be increased and a sufficient braking force can be ensured.

By setting the target slip angle DT _θ based on the map of FIG. 5 and the steering angle θ, for example, when the steering angle θ is close to 0, the target slip angle DT _θ and thus the target slip angle DT becomes a large value, and the vehicle CR Can be directed to the road surface on the high friction coefficient side, so that the driver can be prompted to correct the rudder. And the differential pressure can be increased by the modified rudder, and the braking force can be secured.

By setting the target slip angle DT _V based on the map of FIG. 4 and the vehicle speed V, when the vehicle speed V is large, the target slip angle DT _V and thus the target slip angle DT becomes a small value, and the direction of the vehicle CR is changed. Since it can approach the traveling direction, the posture of the vehicle CR can be stabilized.

Since the smaller value of the target slip angle DT _θ calculated based on the steering angle θ and the target slip angle DT _V calculated based on the vehicle speed V is set as the target slip angle DT, the steering angle θ and the vehicle Based on the speed V, the target slip angle DT can be set satisfactorily.

  Since the differential pressure setting means 150 calculates the differential pressure based on the slip angle D, the target slip angle DT, the steering angle θ, and the vehicle speed V, the differential pressure can be set with high accuracy.

  In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.

  In the above embodiment, the differential pressure setting means 150 as the braking force difference setting means is configured to set the differential pressure DP as the braking force difference. However, the present invention is not limited to this, for example, the braking force The difference setting means may be configured to set the braking force difference itself.

  In the above embodiment, the target slip angle setting unit 121 is configured to set the target slip angle DT based on the vehicle speed V and the steering angle θ, but the present invention is not limited to this. For example, the target slip angle setting means may be configured to set the target slip angle based only on the vehicle speed, or may be configured to set the target slip angle based only on the steering angle. Further, the target slip angle may be a fixed value. The target slip angle may be set in advance according to the elapsed time from the start of the differential pressure setting. According to this, variation in the direction of the vehicle CR with respect to the traveling direction of the vehicle CR can be further suppressed.

  In the above embodiment, the target slip angle DT is maintained while the split road is determined, but the present invention is not limited to this. For example, when the differential pressure becomes a predetermined value or more, the target slip angle setting means may converge the target slip angle toward 0. Specifically, for example, the target slip angle setting means determines whether or not the differential pressure has become a predetermined value or more based on the differential pressure information output from the differential pressure setting means, and the differential pressure is a predetermined value. In such a case, the next target slip angle is set to a value smaller than the current target slip angle by a predetermined amount. When the current target slip angle becomes zero, the next target slip angle is set to zero thereafter. Can be configured to. According to this, when the differential pressure on the left and right becomes large, that is, when the braking force is sufficiently secured, the target slip angle becomes small, so that the direction of the vehicle can be brought close to the traveling direction, and the posture of the vehicle is stabilized. Can be made.

  In the above embodiment, the vehicle brake control device A using the brake fluid is illustrated, but the present invention is not limited to this. For example, the electric brake that generates the brake force by the electric motor without using the brake fluid. It may be a vehicle brake control device for controlling the device.

122 slip angle acquisition means 150 differential pressure setting means A vehicle brake control device CR vehicle D slip angle DT target slip angle

Claims (7)

Slip angle acquisition means for acquiring a slip angle that is an angle formed by the traveling direction of the vehicle and the direction of the vehicle;
Braking force difference setting means for setting a difference between the braking force of the wheel brake on the high friction coefficient side and the braking force of the wheel brake on the low friction coefficient side on a split road where the friction coefficient of the ground contact road surface of the wheel is different from the left and right by a predetermined amount; ,
A target slip angle setting means for setting the target slip angle based on at least the steering angle ,
The braking force difference setting means, such that the slip angle to follow the target slip angle, and set the difference of the braking force,
The target slip angle setting means sets the target angle as the steering angle increases when the steering angle is positive when the steering angle is positive when steering the vehicle toward the road surface on the low friction coefficient side. A vehicular brake control device , wherein a slip angle is set small and a target slip angle is set to a constant value equal to or greater than a value when the steering angle is positive when the steering angle is 0 or less . Slip angle acquisition means for acquiring a slip angle that is an angle formed by the traveling direction of the vehicle and the direction of the vehicle;
Braking force difference setting means for setting a difference between the braking force of the wheel brake on the high friction coefficient side and the braking force of the wheel brake on the low friction coefficient side on a split road where the friction coefficient of the ground contact road surface of the wheel is different from the left and right by a predetermined amount; ,
A target slip angle setting means for setting the target slip angle based on at least the vehicle speed ,
The braking force difference setting means, such that the slip angle to follow the target slip angle, and set the difference of the braking force,
The target brake angle setting means sets the target slip angle to a smaller value as the vehicle speed increases . Slip angle acquisition means for acquiring a slip angle that is an angle formed by the traveling direction of the vehicle and the direction of the vehicle;
Braking force difference setting means for setting a difference between the braking force of the wheel brake on the high friction coefficient side and the braking force of the wheel brake on the low friction coefficient side on a split road where the friction coefficient of the ground contact road surface of the wheel is different from the left and right by a predetermined amount; ,
A target slip angle setting means for setting the target slip angle based on the steering angle and the vehicle speed ,
The braking force difference setting means, such that the slip angle to follow the target slip angle, and set the difference of the braking force,
The target slip angle setting means sets the smaller value of the target slip angle calculated based on the steering angle and the target slip angle calculated based on the vehicle speed as the target slip angle. Brake control device for a vehicle. Slip angle acquisition means for acquiring a slip angle that is an angle formed by the traveling direction of the vehicle and the direction of the vehicle;
Braking force difference setting means for setting a difference between the braking force of the wheel brake on the high friction coefficient side and the braking force of the wheel brake on the low friction coefficient side on a split road where the friction coefficient of the ground contact road surface of the wheel is different from the left and right by a predetermined amount; With
The braking force difference setting means sets the braking force difference so that the slip angle follows the target slip angle ,
The braking force difference setting means includes
Calculating a first braking force difference based on a deviation between the slip angle and the target slip angle;
Based on the steering angle, the second braking force difference is calculated,
A vehicular brake control apparatus , wherein the difference in braking force is set by adding the first braking force difference and the second braking force difference . 5. The vehicle according to claim 4 , wherein the target slip angle is set in advance corresponding to an elapsed time from the time when the setting of the braking force difference is started by the braking force difference setting means. Brake control device. The said target slip angle is set to the angle which the direction of a vehicle faces the road surface of the high friction coefficient side with respect to the advancing direction, The any one of Claims 1-5 characterized by the above-mentioned. Vehicle brake control device. The target slip angle setting means, the target slip angle, when the difference of the braking force exceeds a predetermined value, claims 1 to 6, characterized in that converges towards 0 The vehicle brake control device according to any one of the above.

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