JP2007050742A - Brake control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake control device of a vehicle improving responsiveness while restraining occurrence of control hunting. <P>SOLUTION: This braking force control device of the vehicle furnished with a braking force detection means to detect a braking state of each wheel, a target braking force computing means to compute actual braking force and target braking force in accordance with the actual braking force detected by the braking force detection means and a braking force control means having a gain to multiply to deflection of the actual braking force and the target braking force and to control braking force of each of the wheels changes a value of the gain when time gradient of the target braking force is lower than a predetermined value in intensifying pressure and a difference is lower than a predetermined value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle braking control device that obtains a braking force by controlling a hydraulic pressure in a wheel cylinder.

Conventionally, for example, a technique disclosed in Patent Document 1 is disclosed as a braking control device for a vehicle. In the vehicle braking control device described in this publication, the deviation between the actual hydraulic pressure of the wheel cylinder pressure and the target hydraulic pressure is multiplied by a constant gain, and the wheel cylinder pressure is calculated based on the product of the gain and the deviation. Increase or decrease.
JP-A-8-150909

  However, in the above prior art, when the gain is set high to improve the response, overshoot occurs just before the actual hydraulic pressure converges to the target hydraulic pressure, which may lead to control hunting. Therefore, when the pressure increasing valve is opened, the hydraulic pressure increases excessively, and the pressure reducing valve is opened in order to reduce the excessively increased hydraulic pressure, which may deteriorate the riding comfort during braking.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a vehicle braking control device that improves the responsiveness while suppressing the occurrence of control hunting.

  In order to achieve the above object, the present invention calculates a braking force detection means for detecting the braking state of each wheel and a target braking force for each wheel based on the actual braking force detected by the braking force detection means. A target braking force calculating means; and a braking force control means having a gain for multiplying the deviation between the actual braking force and the target braking force, and controlling the braking force of each wheel based on the product of the gain and the deviation. In the vehicle braking force control apparatus, the braking force control means is configured to increase the gain when the time gradient of the target braking force is not more than a predetermined value and the difference is not more than a predetermined value at the time of pressure increase. The value was changed.

  Therefore, it is possible to provide a vehicle braking control device that improves the responsiveness while suppressing the occurrence of control hunting.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for realizing a vehicle braking control apparatus according to the present invention will be described below based on an embodiment shown in the drawings.

[System Configuration]
Example 1 will be described with reference to FIGS. FIG. 1 is a system configuration diagram of a vehicle braking control apparatus. The braking control device of the vehicle of the present application is a so-called brake-by-wire system, and the front wheel is provided with a hydraulic brake device, while the rear side employs a system that electrically controls the brake without using hydraulic pressure. In this embodiment, the braking control of the hydraulic brake device will be described.

  The master cylinder 1 is provided with a stroke sensor 2 and a stroke simulator 3. As the brake pedal 4 is depressed, hydraulic pressure is generated in the master cylinder 1 and a stroke signal of the brake pedal 4 is output to the main ECU 10. The generated master cylinder pressure is supplied to the hydraulic unit 200 through the oil passages 31 and 32, and is supplied to the front wheel side wheel cylinder 5 through the rear oil passages 33 and 34 subjected to hydraulic pressure control.

  The main ECU 10 calculates the target hydraulic pressure of the front wheels in consideration of the vehicle state quantity such as the vehicle speed and the yaw rate based on the stroke signal, and outputs a command signal to the hydraulic unit 200 via the brake ECU 100 to output the hydraulic pressure of the wheel cylinder 5. And the front wheels are braked by the regenerative braking device 9 during braking. The rear wheel side brake actuator 6 controls the braking force of the electric caliper 7 based on a command signal from the main ECU 10. Further, the wheel speed VSP from the wheel speed sensor 8 provided for each wheel FL to RR is input to the brake ECU 100.

  The hydraulic pressure unit 200 shuts off the communication between the master cylinder pressure and the wheel cylinder 5 by the shut-off valves 21 and 22 during normal braking in the brake-by-wire system. On the other hand, hydraulic pressure is supplied to the wheel cylinder 5 by the pumps P1 and P2, and a braking force is generated. Further, when the wheel tends to be locked due to the driver's sudden braking operation, the pressure increasing valve is driven to release the lock, and the supply of hydraulic pressure from the master cylinder 1 side to the front wheel side wheel cylinder 5 is shut off.

  Then, by appropriately driving the pressure reducing valve, the hydraulic pressure in the front wheel side wheel cylinder 5 is reduced, and a braking force is obtained while avoiding the locking of the wheels. Further, when the brake-by-wire function fails, the master cylinder pressure is supplied to the front wheel cylinder 5 to obtain the braking force.

  In this embodiment, the oil passage configuration for supplying the master cylinder pressure to the rear-wheel brake actuator 6 is not provided. In other words, the rear wheel has a smaller braking force than the front wheel (generally, the braking force ratio between the front wheel and the rear wheel is about 7: 3), and even if a failure occurs, a sufficient braking force can be secured only with the front wheel. is there.

[Hydraulic circuit diagram of hydraulic unit]
FIG. 2 is a hydraulic circuit diagram of the hydraulic unit 200. The hydraulic unit 200 is a tandem type unit composed of an S system connected to the left front wheel and a P system connected to the right front wheel. The wheel cylinder pressure is raised by pumps P1 and P2 (driven by motors M1 and M2 respectively) provided independently on the left and right sides to obtain a desired braking force. Note that the pressure may be increased by one motor and pump in both the P system and the S system, and there is no particular limitation.

  The master cylinder 1 is connected to the wheel cylinders 5 and 5 through oil passages 31 and 32, normally open (that is, valve opening in non-excitation) shut-off valves 21 and 22, and oil passages 33 and 34. One of the pumps P1 and P2 is connected to the master cylinder 1 via the oil passages 41 and 42, and the other is connected to the oil passages 43 and 44.

  The oil passages 43 and 44 are provided with normally open in valves 23 and 24, which are connected to the oil passages 45 and 46 and the oil passages 47 and 48, respectively. The oil passages 45 and 46 are provided with out valves 25 and 26 which are normally closed proportional valves, and are connected to the oil passages 41 and 42. The oil passages 47 and 48 are connected to the oil passages 33 and 34. Furthermore, check valves 27 and 28 that allow only the flow from the pumps P1 and P2 to the in-valves 23 and 24 are provided in the oil passages 43 and 44, respectively.

  Hydraulic pressure sensors 51 and 52 for detecting the master cylinder pressure are provided between the master cylinder 1 and the shut-off valves 21 and 22 in the oil passages 31 and 32. Further, hydraulic pressure sensors 53 and 54 for detecting the wheel cylinder pressure are also provided between the oil passages 33 and 34 and the connection points between the wheel cylinders 5 and 5 and the oil passages 47 and 48. The detected hydraulic pressure is output to the main ECU 10.

(When pressure is increased)
When the pressure is increased, hydraulic oil is pumped from the reservoir 11 via the oil passages 41 and 42 by the pumps P1 and P2, and the wheel cylinders 5 and 5 are increased via the normally open in valves 23 and 24. At this time, the normally open shut-off valves 21 and 22 are closed, and the master cylinder pressure is not introduced into the wheel cylinders 5 and 5. Further, the out valves 25 and 26 are also closed to shut off the wheel cylinder pressure and the reservoir 11.

(At reduced pressure)
During decompression, the pumps P1 and P2 are stopped, and the out valves 25 and 26 are opened. Thus, the wheel cylinders 5 and 5 communicate with the reservoir 11 via the oil passages 47 and 48, and the wheel cylinder pressure is reduced.

(When holding)
At the time of holding, the pumps P1 and P2 are stopped, and the out valves 25 and 26 and the shutoff valves 21 and 22 are closed. As a result, the wheel cylinders 5 and 5 are disconnected from the master cylinder 1 and the reservoir 11, and the hydraulic pressure is maintained.

(During fail)
At the time of failure, the solenoid valves 21 to 26 are not energized, the normally open shutoff valves 21 and 22 and the in valves 23 and 24 are automatically opened, and the normally closed out valves 25 and 26 are closed. Thereby, the master cylinder 1 and the wheel cylinders 5 and 5 are communicated with each other, the wheel cylinders 5 and 5 and the reservoir 11 are shut off, and a manual brake is secured.

[Details of brake ECU]
FIG. 3 is a control block diagram of the brake ECU 100. The brake ECU 100 includes a normal brake braking force calculation unit 110, an ABS control unit 120, a control switching unit 130, and a servo control unit 140 (target hydraulic pressure calculation means).

  The normal brake braking force calculation unit 110 calculates a normal brake required hydraulic pressure Pn during normal braking based on the pedaling force and pedal stroke amount output from the brake pedal 4 and outputs them to the ABS control unit 120 and the control switching unit 130.

  The ABS control unit 120 calculates the braking force P * during ABS control based on the normal brake target hydraulic pressure Pn and the wheel speed VSP, and outputs the braking force P * to the control switching unit 130. At the start of ABS control, the ABS control flag F1 is set and output to the control switching unit 130.

  The control switching unit 130 selects and outputs either the normal brake required hydraulic pressure Pn or the ABS required hydraulic pressure Pabs. If the ABS control flag F1 = 1, the ABS required hydraulic pressure Pabs is selected, and if F1 = 0, the normal brake required hydraulic pressure Pn is selected.

  The servo control unit 140 calculates the actual hydraulic pressure P of the wheel cylinder 5, the normal brake required hydraulic pressure Pn, and the ABS required hydraulic pressure Pabs, and selects one of them to output as the target hydraulic pressure Pr. Further, the target voltage Vm * of the motors M1 and M2 and the target current Iv * of the electromagnetic valves 21 to 26 are calculated based on the power supply voltage V and the actual current value i of the electromagnetic valves 21 to 26, and the motors M1, M2 and electromagnetic Output to the target current Iv * of the valves 21-26.

[Control configuration of servo control unit]
FIG. 4 is a control block diagram of the servo control unit 140. The servo control unit 140 includes a mode switching unit 141, a feed forward (FF) control unit 142, a feedback (FB) control unit 143, a final target hydraulic pressure determination unit 144, a motor voltage conversion unit 145, and an electromagnetic valve current conversion unit 146.

A target hydraulic pressure Pr is input to the mode switching unit 141, and an actual hydraulic pressure P from the wheel cylinder 5 is also input. Based on this target hydraulic pressure Pr, a control mode command is output to the final target hydraulic pressure determination unit 144. When the target hydraulic pressure Pr = normal brake required hydraulic pressure Pn, the normal mode command is output, and when the target hydraulic pressure Pr = ABS required hydraulic pressure Pabs, the ABS control mode is output.
Further, when the deviation between the target hydraulic pressure Pr and the actual hydraulic pressure P of the wheel cylinder 5 at the start of ABS control exceeds a specified value, forced sudden pressure reduction / forced holding / forced so as to quickly reach a desired hydraulic pressure. Outputs any control mode command for sudden pressure increase.

  The target hydraulic pressure Pr is input to the FF control unit 142. The input target hydraulic pressure Pr is subjected to feedforward control, and is output to the final target hydraulic pressure determining unit 144 as the target hydraulic pressure FF component P * (FF).

  The FB control unit 143 performs PID control on the difference ΔP between the target hydraulic pressure Pr and the actual hydraulic pressure P, and outputs it to the final target hydraulic pressure determination unit 144 as the target hydraulic pressure FB component P * (FB).

  The final target hydraulic pressure determination unit 144 determines the final target hydraulic pressure P * of the wheel cylinder 5 based on each control mode input from the mode switching unit 141. During normal operation and ABS control, the FF component P * (FF) and the FB component P * (FB) of the final target hydraulic pressure P * input are superimposed and output as the final target hydraulic pressure P *.

  Here, the forced rapid pressure reduction / forced hold / forced rapid pressure increase mode is the FF and FB components of the final target hydraulic pressure P * are calculated in the FB and FB control units 142 and 143 during the ABS control, and the final target hydraulic pressure P *. The hydraulic pressure of the wheel cylinder is forcibly increased / decreased until the calculation of = P * (FF) + P * (FB) is completed. That is, in the forced rapid pressure reduction / forced holding / forced rapid pressure increase mode, the calculation in the FF control unit 142 and the FB control unit 143 is shortcutted to perform pressure reduction / holding / pressure increase.

  The motor voltage conversion unit 145 corrects the motor control voltage Vm based on the power supply voltage and outputs it as a voltage correction value Vmγ to the motors M1 and M2. Similarly, the solenoid valve current converter 146 also corrects the current value Iv based on the power supply voltage, and outputs the solenoid valve current correction value Ivγ to each of the solenoid valves 21 to 26.

[Details of feedback control unit]
FIG. 5 is a control block diagram of the feedback control unit 143. The feedback control unit 143 includes a high-pass filter (HPF) 143a, a hydraulic pressure determination unit 143b, a correction gain setting unit 143c, and a PID control unit 143d. The target hydraulic pressure Pr is input to the high pass filter 143a, and each differential value is output as dPr / dt.

The hydraulic pressure determination unit 143b determines whether or not the target hydraulic pressure Pr is in a steady state, and if it is in a steady state, outputs it as a steady state flag F = 1. Otherwise, F = 0.
Specifically, when pressure is increased (dPr / dt> 0), if dPr / dt is less than or equal to the threshold value dPu and the deviation ΔP between the target fluid pressure Pr and the actual fluid pressure P is less than or equal to the threshold value ΔPu, the steady state F = 1 is output.
On the other hand, when dPr / dt is equal to or greater than the threshold value dPd and the difference ΔP between the target hydraulic pressure Pr and the actual hydraulic pressure P is equal to or greater than the threshold value ΔPd at the time of pressure reduction (dPr / dt <0), F = 1 is output.

The correction gain setting unit 143c sets the correction gain Kγ to 1 when the steady state flag F = 0. When F = 1, correction gains Kpγ, Kiγ, and Kdγ for the proportional term P, integral term I, and differential term D in PID control are set.
When F = 1, the correction gain is set independently at the time of pressure increase and at the time of pressure reduction, and is indicated by Ku at the time of pressure increase and Kd at the time of pressure reduction. Set gains corresponding to proportional, integral, and differential terms during pressure increase and pressure decrease.

In order to ensure control stability when the gain is changed, the correction gain for the proportional term and the differential term is set to less than 1 for both pressure increase and pressure reduction. However, the correction gain for the integral term is set to 1 for both pressure increase and pressure decrease. It shall be exceeded. That is, each correction gain is set as follows.
Proportional term gain Kupγ, Kdpγ <1
Integral term gain Kuiγ, Kdiγ> 1
Differential term gain Kudγ, Kddγ <1

  The PID control unit 143d multiplies the deviation ΔP by the normal gain K and each correction gain Kγ to calculate a proportional term, an integral term, and a differential term, and takes each sum to obtain an FB component Pn that is a feedback control amount of the required hydraulic pressure Pr. (FB) or Pabs (FB) is output.

[Correction gain setting in feedback control unit]
In order to avoid the control hunting that occurs when the gain K is set high to improve the response, the gain may be lowered just before the actual hydraulic pressure P converges to the target hydraulic pressure Pr.

  Therefore, in this embodiment, the value of the correction gain Kγ is changed when dPr / dt is less than the threshold value dPu and the difference ΔP is less than the threshold value ΔPu at the time of pressure increase. On the other hand, at the time of decompression, the value of the correction gain Kγ is changed when dPr / dt exceeds the threshold value dPd and the difference ΔP exceeds the threshold value ΔPd.

  In particular, when the pumps P1 and P2 are driven by the motors M1 and M2 and the wheel cylinder pressure is increased as in the hydraulic circuit of the present application, the pressure increase command is changed to the hold command due to the inertia of the motor and the pump. However, since the pump may continue to rotate and increase the pressure, gain change control is effective.

[Feedback control processing during pressure increase]
FIG. 6 is a flowchart showing the flow of feedback control processing during pressure increase. Hereinafter, each step will be described.

  In step S101, it is determined whether dPr / dt <dPu. If YES, the process proceeds to step S102, and if NO, the process proceeds to step S107.

  In step S102, it is determined whether or not ΔP <ΔPu. If YES, the process proceeds to step S103, and if NO, the process proceeds to step S107.

  In step S103, the steady-state determination flag F is set to 1, and the process proceeds to step S104.

  In step S104, the pressure increase side proportional term Puγ is calculated by multiplying the deviation ΔP by the proportional increase pressure normal gain Kup and the pressure increase correction gain Kγup, and the process proceeds to step S105.

  In step S105, the pressure increase side steady time integral term Iuγ is calculated by multiplying the integral value of the deviation ΔP by the integral term pressure increase normal gain Kui and pressure increase correction gain Kγui, and the process proceeds to step S106.

  In step S106, the differential value of the deviation ΔP is multiplied by the normal pressure Kud at the time of pressure increase of the differential term and the correction gain Kγud at the time of pressure increase to calculate the pressure increasing side differential term Duγ, and the process proceeds to step S111.

  In step S107, the steady state determination flag F = 0 is set, and the process proceeds to step S108.

  In step S108, the normal pressure increasing proportional term Pu is calculated by multiplying the deviation ΔP by the normal pressure increasing normal gain Kup, and the process proceeds to step S109.

  In step S109, the integral value of the deviation ΔP is multiplied by the normal gain Kui at the time of increasing the integral term to calculate the normal pressure increasing integral term Iu, and the process proceeds to step S110.

  In step S110, the differential value of the deviation ΔP is multiplied by the normal gain Kud at the time of pressure increase of the differential term to calculate the normal pressure increase time differential term Du, and the process proceeds to step S111.

  In step S111, the sum Puγ + Iuγ + Duγ or Pu + Iu + Du of each component at the normal time or normal time is output as the pressure-increasing side FB control amount = Pn (FB) or Pabs (FB), and the control is terminated.

[Feedback control process during decompression]
FIG. 7 is a flowchart showing the flow of feedback control processing during decompression. Hereinafter, each step will be described.

  In step S201, it is determined whether dPr / dt> dPu. If YES, the process proceeds to step S202, and if NO, the process proceeds to step S207.

  In step S202, it is determined whether or not ΔP> ΔPu. If YES, the process proceeds to step S203, and if NO, the process proceeds to step S207.

  In step S203, the steady-state determination flag F = 1 is set, and the process proceeds to step S204.

  In step S204, the depressurization-side steady-time proportional term Pdγ is calculated by multiplying the deviation ΔP by the proportional-decreasing normal gain Kdp and the depressurizing correction gain Kγdp, and the process proceeds to step S205.

  In step S205, the decompression side steady-time integral term Idγ is calculated by multiplying the integral value of the deviation ΔP by the decompression normal gain Kdi and decompression correction gain Kγdi, and the process proceeds to step S206.

  In step S206, the differential value of the deviation ΔP is multiplied by the normal pressure Kdd during decompression and the correction gain Kγdd during decompression to calculate the steady-state differential term Ddγ during decompression, and the process proceeds to step S211.

  In step S207, the steady-state determination flag F = 0 is set, and the process proceeds to step S208.

  In step S208, the deviation ΔP is multiplied by the normal pressure-decreasing gain Kdp of the proportional term to calculate the normal pressure-decreasing proportional term P, and the process proceeds to step S209.

  In step S209, the integral value of deviation ΔP is multiplied by the decompression normal gain Kdi of the integral term to calculate the normal decompression integral term I, and the process proceeds to step S210.

  In step S210, the differential value of the deviation ΔP is multiplied by the normal gain Kdd during decompression of the derivative term to calculate the normal decompression differential term D, and the process proceeds to step S211.

  In step S211, the sum Pdγ + Idγ + Ddγ or Pd + Id + Dd of the respective components at the normal time or the normal time is output as the decompression side FB control amount = Pn (FB) or Pabs (FB), and the control is ended.

[Contrast of change with time in conventional example and this application]
FIG. 8 is a time chart showing the contrast between the conventional example and the change in hydraulic pressure of the present application. The thin solid line is the target hydraulic pressure Pr, the thick line is the actual hydraulic pressure P in the present application, and the broken line is the actual hydraulic pressure P ′ in the conventional example.

(Time t1)
At time t1, a pressure increase request is output, the target hydraulic pressure Pr rises, and the actual hydraulic pressure P rises.

(Time t2)
At time t2, the target hydraulic pressure Pr reaches a steady state, and the time gradient of the target hydraulic pressure Pr becomes dPr / dt <threshold dPu.

(Time t3)
At time t3, the difference ΔP <threshold value ΔPu between the target hydraulic pressure Pr and the actual hydraulic pressure P is satisfied, and in the present application, the steady state determination flag F = 1, the value of the correction gain Kγ is changed, and the steady state FB control amount P * ( FB) Output γ. For this reason, in the present application, the difference between the target hydraulic pressure Pr and the actual hydraulic pressure P is small.
On the other hand, in the conventional example, the value of the gain K is not changed at the normal time, so the actual hydraulic pressure P ′ greatly exceeds the target hydraulic pressure Pr. When the wheel cylinder pressure is increased by a motor-driven pump, the pressure cannot be increased and maintained quickly due to the inertia of the pump and motor. Therefore, the influence of response delay becomes remarkable.

(Time t4)
At time t4, the actual hydraulic pressure P ′ and P = target hydraulic pressure Pr are obtained in both the conventional example and the present application.

(Time t5)
At time t5, the actual hydraulic pressures P and P ′ become the same value as the target hydraulic pressure Pr in both the present application and the conventional example.

(Time t6)
At time t6, a pressure reduction request is output, and the target hydraulic pressure Pr tends to decrease. Although the actual hydraulic pressures P and P ′ of the present application and the conventional example start to decrease, in the conventional example, a response delay occurs because the gain value is not changed.

(Time t7)
The target hydraulic pressure Pr becomes 0 at time t7.

(Time t8)
At time t8, the actual hydraulic pressures P and P ′ become 0 in both the present application and the conventional example.

[Effect of the embodiment of the present application]
In the present embodiment, correction is performed when the time gradient dPr / dt of the target hydraulic pressure Pr is less than the threshold value dPu and the difference ΔP between the target hydraulic pressure Pr and the actual hydraulic pressure P is less than the threshold value ΔPu at the time of pressure increase. The value of the gain Kγ is changed. On the other hand, at the time of decompression, the value of the correction gain Kγ is changed when dPr / dt exceeds the threshold value dPd and the difference ΔP exceeds the threshold value ΔPd.

  Thereby, responsiveness can be improved, suppressing generation | occurrence | production of control hunting. In particular, when the pumps P1 and P2 are driven by the motors M1 and M2 and the wheel cylinder pressure is increased as in the hydraulic circuit of the present application, the pressure increase command is changed to the hold command due to the inertia of the motor and the pump. However, since the pump may continue to rotate and increase in pressure, the gain change control of the present application is effective.

(Other examples)
The best mode for carrying out the present invention has been described based on the embodiments. However, the specific configuration of the present invention is not limited to each embodiment, and the scope of the invention is not deviated. Design changes and the like are included in the present invention.

  Further, technical ideas other than the claims that can be grasped from the above embodiments will be described below together with the effects thereof.

(A) In the vehicle braking control device according to claim 1,
The braking force control means executes PID control. When the time gradient of the target braking force is not more than a predetermined value at the time of pressure increase, the gain of the integral term is reduced while the gain of the proportional term and the derivative term in the PID control is reduced. A braking control device for a vehicle, characterized in that the braking control device is increased.

  Control stability when changing the gain can be improved.

(B) In the vehicle braking control device according to claim 1,
The braking force control means executes PID control, and when the time gradient of the target braking force is greater than or equal to a predetermined value during pressure reduction, the gain of the integral term is reduced while the gain of the proportional term and the derivative term in the PID control is reduced. A braking control device for a vehicle, characterized in that the braking control device is increased.

  Control stability when changing the gain can be improved.

(C) In the vehicle braking control device according to (a) above,
The vehicle brake control device, wherein the gain is not changed when the difference is equal to or greater than a predetermined value.

  Responsiveness can be improved when the deviation between the target hydraulic pressure and the actual hydraulic pressure is large.

(D) In the vehicle braking control device described in (b) above,
The vehicle brake control device, wherein the gain is not changed when the difference is equal to or greater than a predetermined value.

  Responsiveness can be improved when the deviation between the target hydraulic pressure and the actual hydraulic pressure is large.

1 is a system configuration diagram of a braking control device for a vehicle of the present application. It is a hydraulic circuit diagram of a hydraulic unit. It is a control block diagram of a brake ECU. It is a control block diagram of a servo control unit. It is a control block diagram of a feedback control unit. It is a flowchart which shows the flow of the feedback control process at the time of pressure increase. It is a flowchart which shows the flow of the feedback control process at the time of pressure reduction. It is a time chart which shows the contrast of a prior art example and the hydraulic pressure change of this application.

Explanation of symbols

1 Master Cylinder 2 Stroke Sensor 3 Stroke Simulator 4 Brake Pedal 5 Wheel Cylinder 6 Rear Wheel Side Brake Actuator 7 Electric Caliper 8 Wheel Speed Sensor 9 Regenerative Brake Device 10 Main ECU
11 Reservoir 21, 22 Shutoff valve 23, 24 In valve 25, 26 Out valve 27, 28 Check valve 31-34 Oil path 41-48 Oil path 51-54 Hydraulic pressure sensor 100 Brake ECU
110 normal brake braking force calculation unit 120 ABS control unit 130 control switching unit 140 servo control unit 141 mode switching unit 142 feedforward control unit 143 feedback control unit 143a high-pass filter 143b hydraulic pressure determination unit 143c correction gain setting unit 143d PID control unit 144 Final target hydraulic pressure determination unit 145 Motor voltage conversion unit 146 Solenoid valve current conversion unit 200 Hydraulic unit FL to RR Wheel M1, M2 Motor P1, P2 Pump

Claims (2)

Braking force detection means for detecting the braking state of each wheel;
Target braking force calculation means for calculating a target braking force of each wheel based on the actual braking force detected by the braking force detection means;
A braking force control for a vehicle, comprising: a gain that multiplies a deviation between the actual braking force and the target braking force; and a braking force control unit that controls a braking force of each wheel based on a product of the gain and the deviation. In the device
The vehicle is characterized in that the braking force control means changes the gain value when the time gradient of the target braking force is equal to or less than a predetermined value and the difference is equal to or less than a predetermined value during pressure increase. Braking control device. Braking force detection means for detecting the braking state of each wheel;
Target braking force calculation means for calculating a target braking force of each wheel based on the actual braking force detected by the braking force detection means;
A braking force control for a vehicle, comprising: a gain that multiplies a deviation between the actual braking force and the target braking force; and a braking force control unit that controls a braking force of each wheel based on a product of the gain and the deviation. In the device
The braking force control means changes the gain value when a time gradient of the target braking force is equal to or greater than a predetermined value and the difference is equal to or greater than a predetermined value during decompression. Braking control device.

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