JP4788659B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device that controls braking force applied to wheels provided in a vehicle.

  2. Description of the Related Art Conventionally, there has been known a brake control device that controls the braking force of a vehicle by generating hydraulic pressure in a hydraulic circuit according to the operating force of a brake pedal and supplying the hydraulic pressure in the hydraulic circuit to a wheel cylinder. It has been.

In such a brake control device, the vehicle may be braked based on information on the master cylinder pressure. Therefore, it is necessary to accurately determine the reference value (0 point) of the master cylinder pressure sensor. In Patent Document 1, in regenerative cooperative control for adjusting regenerative braking force and hydraulic braking force, gain correction is performed on a plurality of read pressure sensor values to calculate a relative pressure value, and the gain-corrected relative pressure value is calculated. On the other hand, a braking device for a vehicle is disclosed in which offset correction is performed to obtain a pressure measurement value that is an absolute pressure value. In the offset correction, the zero pressure learning is performed under the condition that the brake is off and the non-depressurization control is being performed, the offset amount is determined, and the relative pressure value is converted into the absolute pressure value. Patent Document 2 discloses a brake device that corrects a reference value using an average value of output values of a master cylinder pressure sensor when a brake switch is in an OFF state.
JP 2000-177553 A JP 2003-4563 A

  However, in the above-described apparatus, the brake must be turned off in order to correct the reference value, and cannot be corrected until such timing is reached. Therefore, until the reference value is re-corrected, it is necessary to use the reference value that has been used or limit various controls using the reference value. In particular, when the reference value is corrected using the average value of the output values, it takes a certain period of time for the brake to be off, so that it takes longer to complete the correction of the reference value. For this reason, the accuracy of the braking force until the correction of the reference value may be reduced.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for improving the accuracy of the braking force when the correction of the reference value of the master cylinder pressure detection unit is not completed. It is in.

  In order to solve the above problems, a brake control device according to an aspect of the present invention is a brake control device that controls a braking force applied to a wheel provided in a vehicle. A master cylinder that generates pressure, a master cylinder pressure detection unit that detects the master cylinder pressure, an atmospheric pressure estimation unit that estimates atmospheric pressure from vehicle altitude information, and the detected master cylinder pressure and master cylinder pressure detection unit And a control unit for controlling the braking force based on information on the reference value. The control unit is configured to calculate a reference value based on a master cylinder pressure detected during non-braking, in place of the reference value at a timing when the reference value cannot be calculated by the reference value calculation mode. And a provisional value calculation mode for calculating a provisional value based on the atmospheric pressure.

  According to this aspect, at the timing when the reference value cannot be calculated in the reference value calculation mode, the provisional value that replaces the reference value is calculated based on the atmospheric pressure, so that the braking force until the correction of the reference value is completed. Accuracy can be improved.

  The arithmetic unit may calculate the value of the atmospheric pressure as a temporary value when the difference between the master cylinder pressure detected during non-braking and the atmospheric pressure is equal to or less than a predetermined value in the temporary value calculation mode. Accordingly, when the estimated atmospheric pressure is far from the master cylinder pressure due to some factor, it is possible to prevent the braking force from being controlled using this as a temporary value.

  ADVANTAGE OF THE INVENTION According to this invention, the precision of the braking force when correction | amendment of the reference value of a master cylinder pressure detection part is not completed can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In the following embodiments, a brake control device capable of performing regeneration enhancement will be described. However, the brake control device can be appropriately used for other types of brake control devices.

(Schematic configuration of brake control device)
FIG. 1 is a system diagram showing a brake control device 10 according to the embodiment. A brake control device 10 shown in FIG. 1 constitutes an electronically controlled brake system for a vehicle, and independently and independently controls the brakes of the four wheels of the vehicle according to the operation of the brake pedal 12 as a brake operation member by the driver. Set optimally. That is, the brake control device 10 can control the braking force applied to the wheels provided on the vehicle.

  The brake pedal 12 is connected to a master cylinder 14 that sends out brake oil as working fluid (working fluid) in response to a depression operation by the driver. That is, the master cylinder 14 generates a master cylinder pressure according to the operation amount of the brake pedal 12. The brake pedal 12 is provided with a stroke sensor 46 for detecting the depression stroke.

  Further, a reservoir tank 26 is connected to the master cylinder 14, and a reaction force corresponding to the operating force of the brake pedal 12 by the driver is applied to one output port of the master cylinder 14 via the on-off valve 23. A stroke simulator 24 to be created is connected. The on-off valve 23 is a normally closed solenoid valve that is closed when not energized and is switched to an open state when an operation of the brake pedal 12 by the driver is detected.

  A brake hydraulic pressure control pipe 16 for the right front wheel is connected to one output port of the master cylinder 14. The brake hydraulic control pipe 16 is connected to a wheel cylinder 20FR for the right front wheel that applies a braking force to the right front wheel (not shown). A brake hydraulic pressure control pipe 18 for the left front wheel is connected to the other output port of the master cylinder 14, and the brake hydraulic pressure control pipe 18 is for the left front wheel that applies a braking force to the left front wheel (not shown). Connected to the wheel cylinder 20FL.

  A right electromagnetic on-off valve 22FR is provided in the middle of the brake hydraulic control pipe 16 for the right front wheel, and a left electromagnetic on-off valve 22FL is provided in the middle of the brake hydraulic control pipe 18 for the left front wheel. The right electromagnetic on-off valve 22FR and the left electromagnetic on-off valve 22FL are both open when not energized, and are normally open when the operation of the brake pedal 12 by the driver is detected. It is.

  A right master cylinder pressure sensor 48FR for detecting the master cylinder pressure on the right front wheel side is provided in the middle of the brake hydraulic control pipe 16 for the right front wheel. Is provided with a left master cylinder pressure sensor 48FL for measuring the master cylinder pressure on the left front wheel side. Hereinafter, the right master cylinder pressure sensor 48FR and the left master cylinder pressure sensor 48FL are collectively referred to as “master cylinder pressure sensor 48” as appropriate.

  In the brake control device 10, when the brake pedal 12 is depressed by the driver, the stroke sensor 46 detects the amount of depression, which is detected by the right master cylinder pressure sensor 48FR and the left master cylinder pressure sensor 48FL. The depression force (depression force) of the brake pedal 12 can also be obtained from the master cylinder pressure. As described above, it is preferable from the viewpoint of fail-safe that the master cylinder pressure is monitored by the two of the right master cylinder pressure sensor 48FR and the left master cylinder pressure sensor 48FL assuming the failure of the stroke sensor 46.

  On the other hand, one end of a hydraulic supply / discharge pipe 28 is connected to the reservoir tank 26, and a suction port of an oil pump 34 driven by a motor 32 is connected to the other end of the hydraulic supply / discharge pipe 28. . The discharge port of the oil pump 34 is connected to a high pressure pipe 30, and an accumulator 50 and a relief valve 53 are connected to the high pressure pipe 30. In the present embodiment, a reciprocating pump having two or more pistons (not shown) that are reciprocally moved by the motor 32 is employed as the oil pump 34. Further, as the accumulator 50, an accumulator 50 that converts the pressure energy of the brake oil into the pressure energy of an enclosed gas such as nitrogen is stored.

  The accumulator 50 stores brake oil whose pressure has been increased to about 14 to 22 MPa by the oil pump 34, for example. Further, the valve outlet of the relief valve 53 is connected to the hydraulic supply / discharge pipe 28. When the pressure of the brake oil in the accumulator 50 increases abnormally to about 25 MPa, for example, the relief valve 53 is opened and the high-pressure brake is opened. The oil is returned to the hydraulic supply / discharge pipe 28.

  Further, the high-pressure pipe 30 is provided with an accumulator pressure sensor 51 that detects the outlet pressure of the accumulator 50, that is, the pressure of the brake oil in the accumulator 50.

  The high pressure pipe 30 is connected to the right front wheel wheel cylinder 20FR, the left front wheel wheel cylinder 20FL, the right rear wheel wheel cylinder 20RR, and the left rear wheel through the pressure increasing valves 40FR, 40FL, 40RR, 40RL. It is connected to the cylinder 20RL. Hereinafter, the wheel cylinders 20FR to 20RL will be collectively referred to as “wheel cylinders 20”, and the pressure increase valves 40FR to 40RL will be appropriately collectively referred to as “pressure increase valves 40”. Each of the pressure increasing valves 40 is a normally closed electromagnetic flow control valve (linear valve) that is closed when not energized and is used to increase the pressure of the wheel cylinder 20 as necessary.

  A disc brake unit is provided for each wheel of the vehicle (not shown), and each disc brake unit generates a braking force by pressing the brake pad against the disc by the action of the wheel cylinder 20.

  Further, the wheel cylinder 20FR for the right front wheel and the wheel cylinder 20FL for the left front wheel are connected to the hydraulic supply / discharge pipe 28 via the pressure reducing valve 42FR or 42FL, respectively. The pressure reducing valves 42FR and 42FL are normally closed electromagnetic flow control valves (linear valves) used for pressure reduction of the wheel cylinders 20FR and 20FL as necessary. On the other hand, the wheel cylinder 20RR for the right rear wheel and the wheel cylinder 20RL for the left rear wheel are connected to the hydraulic supply / discharge pipe 28 via a pressure reducing valve 42RR or 42RL which is a normally open electromagnetic flow control valve. . Hereinafter, the pressure reducing valves 42FR to 42RL are collectively referred to as “pressure reducing valve 42” as appropriate.

  Since the pressure increasing valve 40 is provided between the accumulator 50 and the wheel cylinder 20, the differential pressure between the front and rear corresponds to the differential pressure between the accumulator 50 and the wheel cylinder 20. The pressure reducing valves 42FR and 42FL are provided between the wheel cylinders 20FR and 20FL and the reservoir tank 26. Since the hydraulic pressure of the reservoir tank 26 is atmospheric pressure, the differential pressure before and after corresponds to the hydraulic pressure of the wheel cylinders 20FR and 20FL. To do.

  Furthermore, since the pressure reducing valves 42RR and 42RL are provided between the wheel cylinders 20RR and 20RL and the reservoir tank 26, a differential pressure acting force according to the hydraulic pressure of the wheel cylinders 20RR and 20RL acts.

  Further, as shown in FIG. 1, the brake control device 10 according to the present embodiment has wheels corresponding to the wheel cylinders 20FR to 20RL for the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel, respectively. Wheel cylinder pressure sensors 44FR, 44FL, 44RR and 44RL for detecting wheel cylinder pressure, which is the pressure of brake oil acting on the cylinder 20, are provided. Hereinafter, the wheel cylinder pressure sensors 44FR to 44RL are collectively referred to as “wheel cylinder pressure sensor 44” as appropriate. The wheel cylinder pressure sensor 44 functions as pressure detection means for detecting the pressure of brake oil as a working fluid acting on the wheel cylinder 20.

  The right electromagnetic on-off valve 22FR and the left electromagnetic on-off valve 22FL, the pressure increasing valves 40FR to 40RL, the pressure reducing valves 42FR to 42RL, the oil pump 34, the accumulator 50, and the like constitute the hydraulic actuator 80 of the brake control device 10. The hydraulic actuator 80 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 200. The ECU 200 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, an input / output interface, a memory, and the like.

  FIG. 2 is a control block diagram of the brake control device 10 according to the present embodiment. As shown in FIG. 2, the ECU 200 is electrically connected to the above-described right electromagnetic on-off valve 22FR, left electromagnetic on-off valve 22FL, on-off valve 23, pressure increasing valves 40FR to 40RL, pressure reducing valves 42FR to 42RL, and the like. . The right electromagnetic on-off valve 22FR, the left electromagnetic on-off valve 22FL, the on-off valve 23, the pressure increasing valves 40FR to 40RL, and the pressure reducing valves 42FR to 42RL are controlled by a valve control unit 201 constructed in the ECU 200, respectively.

  The ECU 200 is given a signal indicating the wheel cylinder pressure in the wheel cylinders 20FR to 20RL from the wheel cylinder pressure sensors 44FR to 44RL, and a signal indicating the ON / OFF state of the brake pedal 12 from the stop lamp switch 49. It is done. That is, the ECU 200 can discriminate between braking and non-braking based on a signal given from the stop lamp switch 49. Further, a signal indicating the depression stroke of the brake pedal 12 is given from the stroke sensor 46 to the ECU 200, and a signal showing the master cylinder pressure is given from the master cylinder pressure sensor 48. Then, the ECU 200 calculates a braking force, a reference value of a master cylinder pressure sensor 48 to be described later from a signal from each sensor, a reference value of the master cylinder pressure sensor 48, and other set values related to braking. And a storage unit 60 such as a memory for storage.

  Further, the brake control device 10 according to the present embodiment includes a GPS (Global Positioning System) receiving unit 54 that receives a signal from a satellite, a navigation control unit 56 that calculates a current position of the vehicle based on the received signal, Is provided.

  The GPS receiver 54 receives time and satellite orbit data transmitted from a plurality of GPS satellites, and transmits the data to the navigation controller 56. The navigation control unit 56 includes storage means in which map information including altitude information, road information, and the like are stored, and the current position of the vehicle including altitude information based on data from GPS satellites received by the GPS receiving unit 54 Is estimated. And the navigation control part 56 estimates the atmospheric pressure of a present position based on the estimated altitude information as an atmospheric pressure estimation part. Thus, it is not necessary to separately provide an atmospheric pressure sensor or the like by using altitude information of a navigation system that is widely used for estimating the atmospheric pressure.

  The brake control device 10 according to the present embodiment controls the braking force based on information on the master cylinder pressure detected by the ECU 200 and the reference value of the master cylinder pressure sensor 48. Therefore, in order to perform braking with high accuracy, the brake control device 10 configured as described above needs to accurately determine the reference value of the master cylinder pressure sensor 48 as the master cylinder pressure detection unit. Therefore, the zero point determination process that becomes the reference value of the master cylinder pressure sensor 48 will be described in detail below.

(Standard value decision processing)
FIG. 3 is a flowchart for explaining an outline including the reference value determination processing in the present embodiment. Note that this processing is not only performed at the time of shipment after manufacture of the vehicle or after replacement of parts related to braking, but may be performed every time immediately after boarding the vehicle, or may be performed at a predetermined timing during use of the vehicle.

  When the initial check process is started by executing the initial check program at a predetermined timing, it is determined whether or not the ignition switch is switched from OFF to ON (S10). If the ignition switch is not switched from OFF to ON, this process is once ended (No in S10). On the other hand, when the ignition switch has been switched from OFF to ON (Yes in S10), the presence or absence of abnormality in the ECU 200, each sensor, etc. is detected (S12), and the reference value determination process of the master cylinder pressure sensor 48 is executed. (S14).

  FIG. 4 is a flowchart for explaining the reference value determination processing shown in FIG. In S20, the ECU 200 determines whether or not the master cylinder pressure sensor 48 is normal from the detection result in S12 shown in FIG. When it is determined that the master cylinder pressure sensor 48 is not normal (No in S20), this is notified to the occupant or the worker by some notification means using a voice, a lamp, or a monitor (S22), and the process is once completed. To do. On the other hand, when it is determined that the master cylinder pressure sensor 48 is normal (Yes in S20), it is determined whether or not the reference value has already been determined. Specifically, for example, the determination may be made with reference to a flag stored in the storage unit 60 or the like indicating whether or not the reference value has been determined.

  When it is determined that the reference value has not been determined (No in S24), the ECU 200 needs to determine the reference value or a highly reliable value corresponding to the reference value as early as possible. Therefore, in such a case, the brake control apparatus 10 according to the present embodiment performs a provisional zero point determination process in the provisional value calculation mode before determining the present zero point as the reference value (S26). Thereafter, the zero point determination process is performed in the reference value calculation mode (S28). On the other hand, when it is determined that the reference value has been determined (Yes in S24), the ECU 200 can control the braking force based on the reference value and the master cylinder pressure detected by the master cylinder pressure sensor 48. The process of S28 is performed without executing the value calculation mode. As a result, the brake control device 10 can correct the reference value again even when the correct reference value of the master cylinder pressure sensor 48 can fluctuate due to changes over time in the sensor and parts related to braking or environmental changes. Therefore, highly accurate braking is possible over a long period of time.

  Note that the reliability of the calculated reference value may be low, for example, when a detection value that deviates from the assumed range is detected as a result of performing this zero point determination process in the reference value calculation mode. In such a case, by setting a reference value invalid flag in a reference value calculation mode to be described later, it is possible to determine whether or not to use the calculated reference value in subsequent processing. Therefore, after performing this zero point determination process in the reference value calculation mode, it is determined whether or not a reference value invalid flag, which will be described later, is set (S30).

  When the reference value invalid flag is set (Yes in S30), the processes of S26 and S28 are repeated again to obtain a valid reference value. On the other hand, when the reference value invalid flag is not set (No in S30), since a valid reference value is determined, the reference value determined flag is set (S32). This reference value determined flag is used in the determination in S24.

  Next, the provisional zero point determination process in the provisional value calculation mode will be described in detail. FIG. 5 is a flowchart for explaining the provisional zero point determination process shown in FIG. The provisional zero point determination process in the provisional value calculation mode is performed in place of the reference value at a timing at which the reference value cannot be calculated by the reference value calculation mode, that is, at a timing before the reference value calculation mode is started in this embodiment. The temporary zero point can be calculated based on the atmospheric pressure.

When this process is started, ECU 200 obtains the altitude information of the current position of the vehicle output from the navigation control unit 56 (S40), to estimate the atmospheric pressure P _A on the basis of the altitude information by the calculation unit 58 (S42). Next, the ECU 200 determines whether or not the vehicle is in a non-braking state at that time from the ON / OFF state of the stop lamp switch 49 and the stroke amount information of the stroke sensor 46 (S44). If it is determined that the vehicle is in a braking state at that time (No in S44), the master cylinder pressure is likely to be a pressure that is significantly different from the atmospheric pressure, and the master cylinder pressure is not detected at this time. Return to S40.

On the other hand, if it is determined that the non-braking state (Yes in S44), ECU 200 obtains the master cylinder pressure _{P M} from the master cylinder pressure sensor 48 (S46), and the atmospheric pressure _{P A} in the arithmetic unit 58 master the difference between the cylinder pressure _{P M} is determined whether more than a predetermined value D1 (S48). If the difference between the atmospheric pressure _{P A} and the master cylinder pressure _{P M} is a predetermined value D1 (Yes in S48), the atmospheric pressure _{P A} to determine the temporary zero point (S50), the temporary zero point to the zero point is determined Is used as a reference point. As a result, at the timing when the reference value cannot be calculated in the reference value calculation mode, the provisional zero point serving as the reference value is calculated based on the atmospheric pressure, so that the determination or correction of the reference value in the reference value calculation mode is completed. It is possible to improve the accuracy of the braking force up to.

On the other hand, the atmospheric pressure estimated by the navigation control unit 56 may not always be accurate depending on the accuracy of signals from GPS satellites, the reception status of the GPS receiving unit 54, the weather, and the like. Therefore, when the difference between the atmospheric pressure P _A and the master cylinder pressure P _M is greater than the predetermined value D1 (No in S48), it is considered to be low reliability estimated atmospheric pressure, it has been used so far The reference value and the design value stored in the storage unit 60 at the time of shipment are determined as temporary 0 points (S52). As described above, in the brake control device 10 according to the present embodiment, when the atmospheric pressure estimated by the calculation unit 58 is far from the master cylinder pressure due to some factor, this is used as a temporary zero point to control the braking force. Is prevented from being performed.

  Next, the zero point determination process in the reference value calculation mode will be described in detail. FIG. 6 is a flowchart for explaining the present zero point determination processing shown in FIG. In the present zero point determination process in the reference value calculation mode, the reference value can be calculated based on the master cylinder pressure detected during non-braking.

When this process is started, initialization of counters, parameters, and the like is performed (S60), for example, the counter C is cleared (the count value of the counter C is 0). ECU200 acquires the master cylinder pressure _{P M} is the output value from the master cylinder pressure sensor 48 (S62). Next, the ECU 200 determines whether or not the vehicle is in a non-braking state at that time from the ON / OFF state of the stop lamp switch 49 and the stroke amount information of the stroke sensor 46 (S64). If it is determined that the vehicle is in a braking state at that time (No in S64), the process returns to S60 and the counter is reset again.

On the other hand, if it is determined that the non-braking state (S64 of Yes), the set to the 0-point determination permission condition is satisfied, acquired by that the master cylinder pressure P _M is 0 point within the allowable range (.alpha.min <P It is determined whether or not _M <αmax) (S66). When the master cylinder pressure P _M is within the allowable range (Yes in S66), the counter is the sum of the output values while not reset Psum, the maximum value Pmax in the output value acquired at predetermined intervals, The minimum value Pmin is obtained by the calculation unit 58 (S68), and the counter C is counted up (the count value is incremented by 1) (S70). Then, whether the count value reaches the set value N ₀ or not it is determined (S72). If the master cylinder pressure P _M is not within the allowable range (No in S66), since the high reference value reliable is not required, it sets the invalid flag reference value (S80).

When the count value is smaller than the set value _{N 0} (No in S72), S62~S70 are repeated. When the count value reaches the set value N ₀ (Yes in S72), it is determined whether or not the value obtained by subtracting the minimum value Pmin from the maximum value Pmax of the output value of the master cylinder pressure sensor 48 is equal to or greater than the set value D2. (S74). When the difference between the maximum value Pmax and the minimum value Pmin is smaller than the set value D2 and the fluctuation of the output value is small (No in S74), the total average value of the plurality of output values acquired from the master cylinder pressure sensor 48 is obtained. The zero point as the reference value is determined (S76). Since the zero point determined in the process so far is a highly reliable value as the reference value, the reference value invalid flag is reset (S78).

  On the other hand, if the difference between the maximum value Pmax and the minimum value Pmin is larger than the set value D2, that is, if the amplitude of the change in the output value is large (Yes in S74), the reference value invalid flag is set because the reference value is not highly reliable. (S80). When the reference value invalid flag is set, the processes of S26 and S28 shown in FIG. 4 are repeatedly executed until the highly reliable book 0 point is determined.

  The brake control device 10 according to the present embodiment controls the braking force of the vehicle using the present 0 point and the provisional 0 point determined as described above. FIG. 7 is a flowchart showing a brake fluid pressure control process according to the present embodiment.

  The supply current to the pressure increasing valve 40 and the pressure reducing valve 42 is controlled according to the execution of the brake fluid pressure control program represented by the flowchart of FIG. When the process is started, it is determined whether or not the stop lamp switch 49 is in an ON state (S90). If the stop lamp switch 49 is not in the ON state (No in S90), this process is once ended. When the stop lamp switch 49 is in the ON state (Yes in S90), it is determined whether or not the reference value determined flag is in the set state (S92). When in the set state (Yes in S92), the zero point is set as the reference value (S94), and when in the reset state (No in S92), the temporary zero point is set as the reference value (S96).

  Then, the master cylinder pressure is obtained based on the output value from the master cylinder pressure sensor 48 and the reference value (S98). For example, a hydraulic pressure corresponding to a value obtained by subtracting 0 point from the output value can be set as the master cylinder pressure. Next, it is determined whether or not the master cylinder pressure is equal to or higher than a set pressure (S100). When the pressure is smaller than the set pressure (No in S100), the process ends with the supply current to the pressure increasing valve 40 and the pressure reducing valve 42 being zero. On the other hand, when the pressure is equal to or higher than the set pressure (Yes in S100), the pedaling force is obtained based on the output value from the stroke sensor 46 and the reference value (S102). The calculation unit 58 determines the required brake hydraulic pressure based on the calculated master cylinder pressure and pedaling force (S104), and the valve control unit 201 sets the pressure increasing valve 40 and the pressure control valve 40 so as to realize the determined required brake hydraulic pressure. A control current for the pressure reducing valve 42 is determined (S106).

  As described above, according to the present embodiment, the provisional zero point can be used as a reference value before the actual zero point is determined. High braking can be performed.

  The present invention has been described with reference to the above-described embodiment. However, this is an exemplification, and the present invention is not limited to the above-described embodiment, and appropriately combines the configurations of the embodiments. And those substituted are also included in the present invention. Various modifications such as design changes can be added to the embodiments based on the knowledge of those skilled in the art, and the embodiments to which such modifications are added can be included in the scope of the present invention. .

It is a distribution diagram showing a brake control device concerning an embodiment. It is a control block diagram of a brake control device according to the present embodiment. It is a flowchart for demonstrating the outline including the reference value determination process in this Embodiment. It is a flowchart for demonstrating the reference value determination process shown in FIG. It is a flowchart for demonstrating the provisional 0 point determination process shown in FIG. It is a flowchart for demonstrating this 0 point determination process shown in FIG. It is a flowchart which shows the brake fluid pressure control process which concerns on this Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Brake control apparatus, 12 Brake pedal, 14 Master cylinder, 16 Brake hydraulic control pipe, 18 Brake hydraulic control pipe, 20 Wheel cylinder, 23 On-off valve, 24 Stroke simulator, 26 Reservoir tank, 40 Pressure increase valve, 42 Pressure reduction valve, 44 Wheel cylinder pressure sensor, 46 stroke sensor, 48 master cylinder pressure sensor, 49 stop lamp switch, 54 GPS receiving unit, 56 navigation control unit, 58 calculation unit, 60 storage unit, 80 hydraulic actuator, 200 ECU, 201 valve control unit.

Claims (2)

In a brake control device for controlling a braking force applied to a wheel provided in a vehicle,
A master cylinder that generates a master cylinder pressure according to the operation amount of the brake operation member;
A master cylinder pressure detector for detecting the master cylinder pressure;
An atmospheric pressure estimation unit that estimates atmospheric pressure from vehicle altitude information;
A controller that controls braking force based on information of the detected master cylinder pressure and a reference value of the master cylinder pressure detector;
The control unit is configured to calculate a reference value based on a master cylinder pressure detected during non-braking, in place of the reference value at a timing when the reference value cannot be calculated by the reference value calculation mode. And a temporary value calculation mode for calculating a temporary value based on the atmospheric pressure.   The calculation unit calculates a value of the atmospheric pressure as a temporary value when a difference between the master cylinder pressure detected during non-braking and the atmospheric pressure is equal to or less than a predetermined value in the temporary value calculation mode. The brake control device according to claim 1.

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