JP2008024039A - Braking force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a braking force control device capable of alleviating a sense of incongruity of a driver due to unintended increase in braking force. <P>SOLUTION: Wheel cylinders 3FR to 3RR in two braking systems are connected to a master cylinder 2 via two shut-off valves 6-1, 6-2. With the shut-off valves 6-1, 6-2 closed, target deceleration G is calculated based on the master cylinder pressure and depressing stroke amount. When only one of the shut-off valves 6-1, 6-2 becomes open, correction is performed such that contribution of the master cylinder pressure becomes larger when the target deceleration G is calculated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a braking force control device capable of controlling the working fluid pressure to the wheel cylinder of each wheel by brake-by-wire, separately from the working fluid pressure from a master cylinder.

As a conventional braking force control device, for example, there is a device described in Patent Document 1. In this device, the master cylinder is connected to the left front wheel cylinder and the right front wheel cylinder via separate switching means (electromagnetic on-off valves), respectively, and can be braked by the master cylinder pressure. .
Further, in the control by brake-by-wire (hereinafter simply referred to as BBW control), the wheel switch of each wheel is set with the pump as a drive source with the two switching means closed and the communication between the master cylinder and the wheel cylinder blocked. The braking force by is controlled.

The target deceleration of the BBW control by the pump is calculated based on both the brake pedal depression stroke amount and the master cylinder pressure. That is, the deceleration Gp is calculated based on the master cylinder pressure, the deceleration Gs is calculated based on the depression stroke amount, and the target deceleration G is calculated by weighting with the contribution degree α as in the following equation.
G = α · Gp + (1-α) Gs
The contribution degree α is set such that the contribution degree of the master cylinder pressure increases as the previous target deceleration (substantially synonymous with the master cylinder pressure) increases, and has an inflection point with a large change rate in the middle.
JP 11-301434 A

  Here, in the BBW control in which a plurality of switching means are provided and the working fluid pressure of the wheel cylinder is increased by a pump which is a driving source different from the master cylinder, the brake pedal is depressed at the time of the BBW control. When braking is performed, only one switching means is switched from the shut-off state to the communication state due to a failure, some wheel cylinders communicate with the master cylinder, and the pressures of the remaining wheel cylinders are calculated as above. Assuming a situation where the target deceleration is controlled, the high-pressure wheel cylinder and the low-pressure master cylinder communicate with each other at the moment when some of the wheel cylinders and the master cylinder are switched from the shut-off state to the communication. The master cylinder pressure rises rapidly. Further, when the master cylinder pressure rises rapidly, a kickback phenomenon occurs in which the brake pedal is pushed back.

When such a kickback phenomenon occurs, the master cylinder pressure suddenly rises even though the brake pedal is not depressed, that is, the depression stroke amount has not increased. Compared to the state, the stepping stroke amount for generating the same master cylinder pressure is shortened. As a result, the deceleration Gs based on the depression stroke amount with respect to the same master cylinder pressure becomes small. Therefore, the deceleration is reduced when the brake pedal is depressed and the contribution degree changes from emphasis on the master cylinder pressure to emphasis on the depression stroke amount. At an inflection point where the rate of change of the contribution rate is large (switching from emphasizing master cylinder pressure to emphasizing the stroke amount), deceleration Gp based on the master cylinder pressure and deceleration based on the stroke amount As the difference from Gs increases, a large change (stepped) occurs in the target deceleration G calculated by the above formula, that is, an unintended variation in braking force occurs during stepping back. Gives the driver a sense of discomfort.
The present invention has been made paying attention to the above points, and an object of the present invention is to provide a braking force control device that can alleviate a sense of incongruity due to a change in braking force not intended by the driver.

In order to solve the above problems, the present invention provides a master cylinder that outputs a master cylinder pressure corresponding to a depression stroke of a driver's brake pedal, a plurality of wheel cylinders that communicate with the master cylinder,
A plurality of switching means for classifying at least two of the plurality of wheel cylinders into a plurality of braking systems, and switching between communication and blocking between the master cylinder and the wheel cylinders provided for each braking system;
Second braking control means for controlling the braking force of the wheel cylinder by a driving source different from the master cylinder in a state of being shut off by the switching means, and the second braking control means is configured to control the master cylinder pressure and the brake pedal. A target deceleration is calculated on the basis of the depression stroke amount and controlled so that the braking force of the wheel cylinder becomes the target deceleration,
In the braking force control device in which the contribution degree of the master cylinder pressure and the depression stroke amount when calculating the target deceleration is set so that the contribution degree of the master cylinder pressure is larger as the master cylinder pressure is larger.
From the state where two or more of the braking systems are shut off by the switching means and the brake pedal is depressed, only a part of the braking systems in the shut-off state has changed from shut-off to communication with the master cylinder. When detecting, contribution degree correction means for correcting the contribution degree so that the contribution degree of the stepping stroke amount becomes small is provided.

  According to the present invention, even if only some of the wheel cylinders communicate with the master cylinder during the BBW control, it is possible to suppress unintended changes in braking force, and to reduce the uncomfortable feeling to the driver.

Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a braking force control apparatus according to the present embodiment.
(Constitution)
In FIG. 1, reference numeral 1 denotes a brake pedal 1 that constitutes a braking operator that is braked by a driver. The brake pedal 1 is connected to a hydraulic pressure booster and a master cylinder 2. The master cylinder 2 is connected to the respective wheel cylinders 3FR to 3RR through the first communication path 5-1 or the second communication path 5-2. In FIG. 1, reference numeral 4 denotes a reservoir.

In the present embodiment, the first communication passage 5-1 is connected to the wheel cylinder 3FR for the right front wheel and the wheel cylinder 3RR for the left rear wheel through the first electromagnetic shut-off valve 6-1. The second communication passage 5-2 is connected to the wheel cylinder 3FL for the left front wheel and the wheel cylinder 3RL for the right rear wheel through the second electromagnetic cutoff valve 6-2.
Here, the electromagnetic shut-off valves 6-1 and 6-2 are in an open state when not energized, and the hydraulic pressure of the master cylinder 2 can be supplied to the wheel cylinders 3FR to 3RR. The electromagnetic shut-off valves 6-1 and 6-2 constitute switching means.

  In the present embodiment, the braking on the right front wheel side and the left rear wheel side communicating with the first communication path 5-1 constitutes the first braking system, and the left front wheel side communicating with the second communication path 5-2 and the right Rear wheel braking constitutes a second braking system, and BBW control is possible by individual pumps 8-1 and 8-2 as will be described later. Of course, the first brake system and the second brake system may be driven by the same pump.

The circuit configurations on the first braking system side and the second braking system side will be described. Since the circuit configuration of the first braking system and the circuit configuration of the second braking system are the same configuration, the configuration will be mainly described for the first braking system.
Reference numerals 7-1, 7-2 and 8-1, 8-2 denote braking force actuators (drive sources different from the master cylinder 4) for generating a braking force in the BBW control. 2 and hydraulic pumps 8-1 and 8-2 driven by the motors 7-1 and 7-2. The operations of the motors 7-1 and 7-2 are controlled by control signals (control currents) from the actuator controllers 9-1 and 9-2, and the hydraulic pump 8- 1 and 8-2 are driven. In FIG. 1, gear pumps are illustrated as the hydraulic pumps 8-1 and 8-2. The hydraulic pumps 8-1 and 8-2 have input ports connected to the reservoir 4 via second pipes 10-1 and 10-2, and discharge ports described above via third pipes 11-1 and 11-2. By being connected to the first communication path 5-1, the working fluid in the reservoir 4 is sucked through the second pipes 10-1 and 10-2, and the working fluid is sucked into the third pipes 11-1 and 11-. 2 can be discharged to the wheel cylinders 3FR to 3RR. In the middle of the third pipes 11-1 and 11-2, holding valves 12-1 and 12-2 made of electromagnetic proportional valves are inserted. The wheel cylinders 3FR to 3RR are connected to the second pipes 10-1 and 10-2 communicating with the reservoir 4 through the fourth pipes 13-1 and 13-2, and the fourth pipes 13-1 and 13-2 are connected. Connected to 13-2 are pressure reducing valves 14-1 and 14-2 comprising electromagnetic proportional valves. Reference numerals 15-1 and 15-2 denote relief valves, and reference numerals 16-1 and 16-2 denote check valves.
Here, each said valve is controlled by the command from corresponding actuator controller 9-1, 9-2.

  In the BBW control state, the shutoff valves 6-1 and 6-2 are closed, and when the pressure is increased, the holding valves 12-1 and 12-2 are opened, and the pressure reducing valves 14-1 and 14- 2 is closed, and the working fluid discharged from the pumps 8-1 and 8-2 is supplied to the wheel cylinders 3 FR to 3 RR to increase the pressure, and when the pressure is reduced, the holding valves 12-1 and 12-2 are closed. In this state, the pressure reducing valves 14-1 and 14-2 are opened, and the working fluid in the wheel cylinders 3FR to 3RR is returned to the reservoir 4 and depressurized. Note that the holding valves 12-1 and 12-2 are appropriately closed when the hydraulic pressure is held by slip control, front / rear braking force distribution control, or the like.

  Further, in FIG. 1, reference numeral 20 denotes a stroke simulator. The stroke simulator 20 is connected to the master cylinder 2 via an electromagnetic opening / closing valve 21. The electromagnetic on-off valve 21 is in a closed state when not energized, and is controlled in an open state in synchronization with the shutoff valves 6-1 and 6-2 being switched to a closed state by a command from the brake controller 22. As a result, the stroke simulator 20 operates. That is, during the BBW control, the master cylinder pressure Pmc is absorbed by the stroke simulator 20 to realize a natural pedal depression force.

The actuator controllers 9-1 and 9-2 are provided for each of the two braking systems, and the actuator controllers 9-1 and 9-2 correspond to the actuators of the corresponding braking system in response to a command from the brake controller 22. Control the state of
Here, reference numeral 24 denotes a stroke sensor, which detects the operation amount of the brake pedal 1 and outputs it to the brake controller 22. Reference numerals 23-1 and 23-2 are pressure sensors provided for each braking system for detecting the master cylinder pressure Pmc (corresponding to the driver's required braking amount). The detected pressure signal is sent to the brake controller 22. Output. The pressure signals detected by the two pressure sensors 23-1, 23-2 are substantially the same except in special cases. Reference numerals 25FR to 25RR are pressure sensors that detect the wheel cylinder pressure Pwc of each of the wheel cylinders 3FR to 3RR, and output the detected pressure signal to the brake controller 22. Reference numerals 26-1 and 26-2 are pressure sensors that detect the discharge pressures of the pumps 8-1 and 8-2, and output the detected pressure signals to the brake controller 22.

  The brake controller 22 is constituted by, for example, a CPU, ROM, RAM, digital port, A / D port, and a one-chip microcomputer incorporating various timer functions (or a plurality of chips realizing the same function). The brake controller 22 outputs control signals to the valves and the motors 7-1 and 7-2 via the actuator controllers 9-1 and 9-2.

During normal control, the brake controller 22 closes the electromagnetic shut-off valves 6-1 and 6-2 as the second braking control state so that the BBW control state is established, and opens the electromagnetic on-off valve 21 for the stroke simulator 20. The stroke simulator 20 is operated as a state to enable a natural pedal effort.
Further, when a failure is detected such that the hydraulic pressure cannot be generated by the pumps 8-1 and 8-2, the first electromagnetic cutoff valve 6-1 and the second electromagnetic cutoff valve 6-2 are set as the first braking control state. Is opened, and the electromagnetic on-off valve 21 for the stroke simulator 20 is returned to the closed state, and the hydraulic pressure of the master cylinder 2 is supplied to each wheel cylinder via the first communication path 5-1 and the second communication path 5-2. Introduced into 3FR-3RR.

Next, the control (BBW control) in the second braking control state in the brake controller 22 will be described. This process constitutes a second braking control means.
In addition, although it does not appear in the following process, when abnormality which may not be able to make all the brake control systems function normally is detected, it supplies with electricity to each valve and motor 7-1, 7-2. That is, the first electromagnetic cutoff valves 6-1 and 6-2 and the second electromagnetic cutoff valves 6-1 and 6-2 are both opened, and the on-off valve 21 for the stroke simulator 20 is closed. The hydraulic pressure of the master cylinder 2 is returned to the wheel cylinders 3FR to 3RR via the first communication path 5-1 and the second communication path 5-2, and the first braking control state is set.

  As shown in FIG. 2, the system operates at a predetermined sampling period. First, in step S10, it is determined whether or not a system failure has occurred. If it is determined that there is a failure, the process proceeds to step S20, which is not a failure. If it is determined, the process proceeds to step S90. The system failure is, for example, a controller failure of one system, a failure of the motors 7-1, 7-2, the pumps 8-1, 8-2, or the like.

In step S20, it is determined whether or not the shut-off valves 6-1 and 6-2 of the brake control system on the failure side are in an open state. If it is determined to be in an open state, the process proceeds to step S30 and is determined to be in a closed state. In this case, the process proceeds to step S90.
In step S30, a stroke fluctuation amount ΔS is obtained based on a signal from the stroke sensor 24, and it is determined whether or not the brake pedal is being returned based on the stroke fluctuation amount ΔS. The process proceeds to S40. If not, that is, if it is determined that the stroke amount S of the brake pedal 1 is maintained or depressed, the process proceeds to Step S90.

Here, the stroke fluctuation amount ΔS is positive in the direction in which the stepping stroke amount S increases. The stroke fluctuation amount ΔS may be a difference from the previous value, or may be obtained from an average value of a plurality of times.
In step S40, it is determined whether or not the brake pedal 1 is returned and the current stroke amount S of the brake pedal 1 is equal to or less than the loss stroke Sloss. If it is equal to or less than the stroke Sloss, the process proceeds to step S90.

  Here, the loss stroke Sloss is the stroke amount at the boundary where the master cylinder pressure Pmc starts to rise when the stroke amount is depressed from zero. When the stroke amount S is from zero to the loss stroke Sloss, it is a non-braking instruction position and the master cylinder 2 and the reservoir 4 are in a communicating state. The kickback phenomenon occurs due to an unexpected backflow of the working fluid from the wheel cylinders 3FR to 3RR to the master cylinder 2, but the master cylinder 2 communicates with the reservoir 4 when the stroke amount S is shorter than the loss stroke Sloss. Since the working fluid that has flowed back to the master cylinder 2 escapes to the reservoir 4, the hydraulic pressure fluctuation does not occur or is small.

In step S50, the master cylinder pressure Pmc0 immediately before the cutoff valves 6-1 and 6-2 are opened, and the cutoff valves 6-1 and 6-2 on the side where the cutoff valves 6-1 and 6-2 are opened. The differential pressure Pdiff from the wheel cylinder pressure Pwc0 immediately before opening is calculated by the following equation, and the process proceeds to step S60.
Pdiff = Pwc0−Pmc0

  Here, the master cylinder pressure Pmc0 and the wheel cylinder pressure Pwc0 immediately before the shut-off valves 6-1 and 6-2 are opened are, for example, when the shut-off valves 6-1 and 6-2 are closed, The latest values of the pressure Pmc and the wheel cylinder pressure Pwc may be always stored. In the present embodiment, since two wheel cylinders 3FR to 3RR are connected to each braking system, one of the pressures of the two wheel cylinders 3FR to 3RR may be set as the wheel cylinder pressure Pwc0. The average value of the pressures of the wheel cylinders 3FR to 3RR may be the wheel cylinder pressure Pwc0.

The process of step S50 is performed only at the first transition from step S40.
In step S60, based on the following equation, a correction reference value Δα0 for the contribution α is calculated based on the differential pressure Pdiff immediately before the occurrence of the kickback phenomenon (stepping stroke amount S0 when a failure occurs), and the process proceeds to step S70.
Δα0 = Pdiff × C1
C1 is a coefficient for converting the differential pressure Pdiff into a contribution correction reference value. Δα0 is a value smaller than 1.

Here, since the kickback phenomenon is larger as the differential pressure Pdiff is larger, the correction reference value Δα0 is set to be larger as the differential pressure Pdiff is larger to increase the correction amount described later. However, Δα0 may be a fixed value.
Further, the contribution degree α may be corrected only when the differential pressure Pdiff is larger than a predetermined threshold value. The predetermined threshold is set in advance, for example, from the viewpoint of whether or not the fluctuation of the master cylinder pressure Pmc occurs more than allowable. Alternatively, the boost gradient ΔP of the master cylinder pressure Pmc immediately after the shutoff valve is opened may be obtained, and the contribution α may be corrected only when it is larger than the threshold value C2. This is because when the differential pressure Pdiff is smaller than a predetermined threshold value or when the pressure increase gradient ΔP of the master cylinder pressure Pmc immediately after the shutoff valve is opened is small, the kickback amount is also small or small.

In step S70, the correction amount Δα of the contribution in the current stepping stroke amount S is calculated based on the following expression, and the process proceeds to step S80.
Δα = Δα0 × (S-Sloss) / (S0-Sloss) (1)
Where, S: Current stepping stroke amount
S0: Depressing stroke amount when the shut-off valve is changed to open.

When the contribution correction amount Δα is calculated by the above equation (1), the contribution correction amount Δα becomes zero when the step is returned to the loss stroke Sloss. If Δα ≦ 0, Δα is set to zero.
In step S80, based on the map as shown in FIG. 3, the contribution α that takes a larger value as the master cylinder pressure Pmc increases is calculated, and the contribution α ′ corrected based on the following equation is calculated for the contribution α. Then, the process proceeds to step S100.
α ′ = α + Δα

  Here, the contribution degree α is a contribution coefficient for weighting that takes a value in the range of 0 to 1, and increases as the master cylinder pressure Pmc increases, and is a predetermined master cylinder pressure Pmc1. In the state where the rate of change is set to be large (the inflection point exists) and is smaller than the predetermined master cylinder pressure Pmc, the degree of contribution of the stepping stroke amount S is large and is larger than the predetermined master cylinder pressure Pmc1. In a large state, the contribution of the master cylinder pressure Pmc is increased.

  Since there is a delay in the generation of the master cylinder pressure Pmc with respect to the start of depression of the brake pedal, the degree of contribution α of the depression stroke amount S is increased when the depression stroke amount S is small. Further, in the relationship between the depression force of the brake pedal 1 and the stroke amount S, the larger the depression stroke amount S, the smaller the increase in the stroke amount S with respect to the increase in the depression force. Therefore, when the depression stroke amount S is large, the master cylinder The contribution of the pressure Pmc is increased. In this embodiment, the degree of inflection is set in the range of the predetermined master cylinder pressure Pmc1.

In the above example, the contribution degree α is obtained from the master cylinder pressure Pmc. However, the contribution degree α may be obtained based on the previous target deceleration Gm−1 or the stepping stroke amount. If the contribution degree α is set so as to increase as the master cylinder pressure Pmc increases, this is substantially equivalent to obtaining the contribution degree α by the master cylinder pressure Pmc.
On the other hand, when it is determined in steps S10 to S40 that the contribution degree α is not corrected and the process proceeds to step S90, the contribution degree α that takes a larger value as the master cylinder pressure Pmc is larger is obtained based on the map as shown in FIG. The process proceeds to step S100.

  In step S100, the target deceleration G is calculated based on the current master cylinder pressure Pmc and the depression stroke amount S of the brake pedal 1, the wheel cylinder pressure Pwc of each wheel that becomes the target deceleration G is calculated, and the wheel cylinder is calculated. The control command value which becomes the pressure Pwc is output to each of the two actuator controllers 9-1 and 9-2 and returned. For example, the control current of the motors 7-1 and 7-2 is controlled based on the difference between the calculated target deceleration G and the current deceleration.

Here, calculation of the target deceleration G of the present embodiment will be described.
The target deceleration Gp due to the master cylinder pressure P is obtained by multiplying the master cylinder pressure P by a predetermined gain K2, for example, based on FIG.
Gp = K2 × Pm
Further, the target deceleration Gs is obtained from the stroke amount S based on a map as shown in FIG.
Then, the final target deceleration G is calculated from the target decelerations Gp and Gs of both the stroke amount S and the master cylinder pressure P based on the following equation.
G = (1−α ′) × Gs + α ′ × Gp (2)
Here, Step S50 to Step S80 constitute contribution correction means.

(Function and effect)
In the braking force control apparatus having the above configuration, in the normal control state (second braking control state), the target deceleration G is calculated based on the master cylinder pressure Pmc and the stepping stroke amount S, and the first braking system and the first braking system In each of the two braking systems, the wheel cylinders 3FR to 3RR are in a high pressure state when the pumps 8-1 and 8-2 are driven and the brake pedal 1 is depressed so that the target deceleration G is obtained. It has become.

  When the brake pedal 1 is depressed at the time of this BBW control, the first braking system side fails, for example, the actuator controller CPU on the first braking system side fails, and the first electromagnetic cutoff valve When 6-1 shifts from closed to open, the right front wheel wheel cylinder 3FR and the left rear wheel wheel cylinder 3RL communicate with the master cylinder 2. At this time, generally, the brake pedal 1 is depressed and the wheel cylinders 3FR and 3RL are higher in pressure than the master cylinder 2, so that the hydraulic pressure in the master cylinder 2 suddenly increases. Further, when the hydraulic pressure in the master cylinder 2 is suddenly increased, a kickback phenomenon occurs in which the brake pedal 1 is pushed back.

  Due to the occurrence of the kickback phenomenon, as shown in FIG. 6, the master cylinder pressure is not increased (slightly decreased) with respect to the characteristics of the normal “stroke-master cylinder pressure” line L as shown in FIG. As a result of the rapid increase in Pmc, the relationship between the master cylinder pressure Pmc and the stepping stroke amount S moves from the point A to the point B. As a result, the relationship between the master cylinder pressure Pmc and the stepping stroke S becomes the characteristic of the line L ′. End. The stepping stroke amount S for the same master cylinder pressure Pmc is reduced. For this reason, when the brake pedal 1 is returned after the kickback phenomenon occurs and the contribution is switched from emphasizing the master cylinder pressure to emphasizing the depression stroke amount when the abnormality occurs as compared with the normal time, the depression stroke amount S is increased. Since the difference between the deceleration Gs based and the deceleration Gp based on the master cylinder pressure Pmc is greatly deviated, the deceleration changes greatly in a stepped manner, giving the driver a sense of incongruity.

  On the other hand, in the present embodiment, the contribution for calculating the target deceleration is corrected so that the contribution on the master cylinder pressure Pmc side is increased (that is, the contribution on the stepping stroke amount S side is reduced). Thus, the brake pedal 1 is returned, and the change in the deceleration when the contribution degree α is switched from the emphasis on the master cylinder pressure to the emphasis on the depression stroke amount is suppressed to be small, that is, the deceleration obtained from the master cylinder pressure Pmc at the time of switching. The difference between Gp and the deceleration Gs obtained from the stepping stroke amount S is reduced, and the driver feels uncomfortable.

  Further, in the state where the contribution at the time of the kickback occurrence is smaller than the predetermined master cylinder pressure Pmc1, that is, in the range where the depression stroke amount is emphasized, the depression stroke for the same master cylinder pressure Pmc as described above. Since the amount S is smaller than that at the normal time, when the brake pedal 1 is returned, the braking force is reduced as compared with the normal time. However, in this embodiment, the contribution α ′ is set to the master cylinder pressure Pmc. By correcting so as to increase the contribution, the braking force is reduced.

  That is, in the present embodiment, the case where the contribution α has an inflection point at a predetermined master cylinder pressure Pmc1 and is clearly divided into a contribution with emphasis on the stepping stroke amount and a contribution with emphasis on the master cylinder pressure. However, this means that the present invention can be applied even when there is no inflection point. Even in this case, as the brake pedal 1 is returned, the contribution of the stepping stroke amount S gradually increases, and there is a possibility that the braking gradually becomes smaller than usual. Since the degree of contribution in calculating the target deceleration on the cylinder pressure side is corrected and increased, the under braking is alleviated.

  Here, when the brake pedal 1 is stepped back after the kickback is generated and the stepping stroke amount S is returned to the loss stroke Sloss or less, the master cylinder 2 communicates with the reservoir 4 so that the master cylinder pressure Pmc is in the initial state. The relationship between the master cylinder pressure Pmc and the depression stroke S returns to the original state (the characteristic state of the line L in FIG. 6). Accordingly, in step S40, once it is detected that the stepping stroke amount S has become equal to or less than the loss stroke Sloss after the occurrence of the kickback phenomenon, the contribution correction is performed so that the process proceeds to step S90 unconditionally in step S40. You may not make it.

  In the above embodiment, the contribution is corrected only when the brake pedal 1 is returned in step S40. However, the steps after step S50 are also performed when the brake pedal 1 is depressed. The contribution degree may be corrected. In this case, for example, only when the master cylinder pressure Pmc0 when the shut-off valve is opened or when the contribution is smaller than the contribution, the contribution correction after step S50 is preferably performed.

In the above correction, the correction amount Δα is set so as to decrease as the master cylinder pressure decreases toward the loss stroke Sloss, but the present invention is not limited to this. For example,
The correction amount Δα itself may be set to gradually increase as the contribution α decreases, or the correction reference value Δα0 itself may be set as the correction amount Δα.
Moreover, although the case where there are two braking systems is illustrated in the above embodiment, the wheel cylinders may be divided into three or more and the braking systems may be classified into three or more systems.

  Moreover, in the said embodiment, although all four wheels are divided into two braking systems, it is not limited to this. For example, the wheel cylinder communicating with the first communication path 5-1 may be only the wheel cylinder 3FR for the right front wheel, and the wheel cylinder communicating with the second communication path 5-2 may be only the wheel cylinder 3FL for the left front wheel. That is, in the second braking control state (BBW control), the four wheels can be braked, and in the second braking state in which the shut-off valves 6-1 and 6-2 are opened, only the front wheels are in a brakeable state. There may be.

(Second Embodiment)
Next, a second embodiment will be described with reference to the drawings. Note that components similar to those in the above-described embodiments will be described with the same reference numerals.
The basic configuration of the present embodiment is the same as that of the first embodiment, and part of the processing of the second braking control state (BBW control) in the brake controller 22 is different.
Next, the brake controller 22 in the present embodiment will be described with reference to FIG. The same processes as those in the first embodiment are given the same step numbers.
That is, the determination as to whether or not the contribution correction is performed, which is the processing in steps S10 to S40, is the same as in the first embodiment, and a description thereof will be omitted.

If the determination in step S40 is satisfied, in this embodiment, the process proceeds to step S200 to detect the contribution degree α0 when the brake pedal is returned, and then in step S210, the contribution degree α ′ is set to the contribution degree α ′. The contribution degree α0 is set and the process proceeds to step S100.
The processes in steps S90 and S100 are the same as those in the first embodiment.

(Function and effect)
When the brake pedal is returned after the kickback phenomenon has occurred with the contribution degree α emphasizing the master cylinder pressure, the contribution degree α0 is fixed to the contribution degree α0 at the start of the return so that the depression stroke amount is emphasized from the master cylinder pressure emphasis. By preventing the switching, it is possible to suppress an abrupt change in deceleration due to the change in the contribution α from the emphasis on the master cylinder pressure to the emphasis on the stepping stroke amount.

Further, even when the kickback phenomenon occurs when the contribution is focused on the depression stroke amount, the target deceleration can be reduced even if the contribution α of the depression stroke amount S is increased by returning the brake pedal 1. Since the contribution degree α ′ at the time of calculation is fixed to the contribution degree α0 at the time of stepping back, excessive deceleration can suppress a decrease.
Here, in this embodiment, only when the brake pedal 1 is returned, the contribution α ′ is fixed and the contribution on the master cylinder pressure side is corrected so as to increase. However, the correction is also made when the brake pedal 1 is depressed. It is good to continue. That is, it is assumed that the brake pedal 1 is stepped on again while the kickback phenomenon occurs and the brake pedal 1 is being returned. In this case, if the correction is not maintained, the contribution may change rapidly. . Even in this case, the contribution degree α0 at the start of return may be fixed.

Moreover, in the said embodiment, although it fixes to the contribution at the time of the return of a brake pedal, you may fix to the contribution immediately before or after the occurrence of kickback.
Other configurations and operational effects are the same as those in the first embodiment.
Here, in all the above embodiments, as shown in the equation (2), the contribution degree of the master cylinder pressure and the contribution degree of the stepping stroke amount are set to be “1”, but the present invention is not limited to this. .

1 is a schematic diagram showing a circuit configuration according to a first embodiment of the present invention. It is a figure explaining the process of the brake controller which concerns on 1st Embodiment based on this invention. It is a figure which shows the relationship between a master cylinder pressure and the contribution coefficient (alpha). It is a figure which shows the relationship between a master cylinder pressure and the target deceleration Gp. It is a figure which shows the relationship between the depression stroke amount and the target deceleration Gs. It is a figure which shows the relationship between a master cylinder pressure and a depression stroke. It is a figure explaining the process of the brake controller which concerns on 1st Embodiment based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Master cylinder 3FR-3RR Wheel cylinder 5-1 1st communication path 5-2 2nd communication path 6-1 and 6-2 Electromagnetic cutoff valve (switching means)
7-1, 7-2 Motor (another drive source)
8-1, 8-2 Pump (another drive source)
9-1, 9-2 Actuator controller 22 Brake controller S Depressing stroke amount S0 Depressing stroke amount Pmc when the shut-off valve is opened Pmc Current master cylinder pressure Pmc0 Master cylinder pressure Pwc immediately before the shut-off valve is opened Wheel cylinder Pressure Pwc0 Foil cylinder pressure α immediately before the shut-off valve is opened α contribution α ′ contribution α0 for calculating the target deceleration α0 contribution Δα when the shut-off valve is opened Correction amount G target deceleration Gp Master cylinder Deceleration based on pressure Gs Deceleration based on stroke amount

Claims (6)

A master cylinder that outputs a master cylinder pressure corresponding to the depression stroke of the brake pedal of the driver, and a plurality of wheel cylinders that communicate with the master cylinder;
A plurality of switching means for classifying at least two of the plurality of wheel cylinders into a plurality of braking systems, and switching between communication and blocking between the master cylinder and the wheel cylinders provided for each braking system;
Second braking control means for controlling the braking force of the wheel cylinder by a driving source different from the master cylinder in a state of being shut off by the switching means, and the second braking control means is configured to control the master cylinder pressure and the brake pedal. A target deceleration is calculated on the basis of the depression stroke amount and controlled so that the braking force of the wheel cylinder becomes the target deceleration,
In the braking force control device in which the contribution degree of the master cylinder pressure and the depression stroke amount when calculating the target deceleration is set so that the contribution degree of the master cylinder pressure is larger as the master cylinder pressure is larger.
From the state where two or more of the braking systems are shut off by the switching means and the brake pedal is depressed, only a part of the braking systems in the shut-off state has changed from shut-off to communication with the master cylinder. A braking force control device comprising: a contribution degree correcting unit that corrects the contribution degree so as to reduce the contribution degree of the stepping stroke amount when detecting.   When the stepping stroke is returned to the non-braking command position after the contribution correction means is activated, only some of the braking systems in the shut-off state have changed from shut-off to communication with the master cylinder. 2. The braking force control apparatus according to claim 1, wherein the contribution correction means does not perform correction until it is detected.   The braking force control apparatus according to claim 1 or 2, wherein the contribution degree correction means operates only when the brake pedal is depressed.   4. The braking force control apparatus according to claim 3, wherein the contribution degree correcting means fixes the contribution degree at the start of returning the brake pedal.   4. The contribution rate of the master cylinder pressure and the stepping stroke amount when calculating the target deceleration is set to have a large change rate within a predetermined master cylinder pressure range. 4. A braking force control device according to 4.   The contribution degree correction means is when the contribution degree of the master cylinder pressure is smaller than the contribution degree immediately before or immediately after a part of the braking systems in the cutoff state is switched from cutoff to communication with the master cylinder. The braking force control device according to any one of claims 1 to 5, wherein the braking force control device operates only in a vehicle.

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