JP6237139B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to vehicle braking that performs regenerative cooperative control in which a hydraulic braking device that generates a master cylinder pressure by a driver's braking operation and a regenerative braking device that generates regenerative braking torque by rotation of a drive wheel are cooperatively operated. The present invention relates to a control device.

2. Description of the Related Art Conventionally, a vehicle brake control device that performs regenerative cooperative control in which a hydraulic brake device that generates a master cylinder pressure by a driver's braking operation and a regenerative brake device that generates a regenerative braking torque by rotation of a drive wheel are cooperatively operated. Is known (see, for example, Patent Document 1).
In this prior art, during the braking operation, during the period from the start of the braking operation to a predetermined stroke, the reservoir port is kept open to increase the master cylinder pressure, that is, the hydraulic braking torque is limited, and the braking torque corresponding to the limit Is obtained by regenerative braking torque. Thereby, the energy recovery amount by regeneration is ensured.
Further, when the vehicle speed decreases due to the braking control, the regenerative braking torque is decreased, and the replacement control for increasing the hydraulic braking torque is executed accordingly.
Further, in the conventional technology, when the regenerative braking torque is increased or decreased, the regenerative braking torque is increased and decreased with a constant gradient. Therefore, the hydraulic braking torque also changes at a rate of change corresponding to the change in the regenerative braking torque.

JP 2006-96218 A

However, if the increasing gradient and decreasing gradient of the regenerative braking torque are set to a constant gradient regardless of the piston stroke amount, the pedal feel may be deteriorated or the recovery amount of the regenerative braking torque may be decreased as described below.
That is, when the hydraulic braking torque corresponding to the change of the regenerative braking torque is obtained by the pump-up hydraulic braking torque actively formed by the pump, the reservoir port is opened in the region where the piston closes the reservoir port. The piston reaction force fluctuation is larger than that in the region. Therefore, when this piston reaction force fluctuation increases, the pedal feel is deteriorated.
On the other hand, when the pump-up hydraulic pressure fluctuation is suppressed so as to suppress the piston reaction force fluctuation, the increase gradient and the decrease gradient of the regenerative braking torque are also suppressed, which may reduce the amount of recovered regenerative energy.

  The present invention has been made paying attention to the above problems, and provides a vehicle brake control device capable of ensuring a recovered amount of regenerative energy while ensuring a good pedal feel by suppressing fluctuations in piston reaction force. Objective.

In order to achieve the above object, a vehicle brake control device of the present invention includes:
A braking controller that controls the total braking torque by coordinating the regenerative braking torque and the hydraulic braking torque by the master cylinder pressure and the pump-up hydraulic pressure according to the braking operation state,
The increase gradient of the regenerative braking torque of the regenerative cooperative control, in the region where the reservoir port is determined to be opened, the gradient setting to set steeper than the region that is determined to reservoir port is closed The vehicle braking control device is characterized in that a regenerative torque increase / decrease gradient setting unit for performing processing is provided.

In the vehicular braking control apparatus of the present invention, in the region where the piston closes the reservoir port, by making the fluctuation gradient of the regenerative braking torque relatively gentle, compared to the case where the gradient is made relatively steep, Piston reaction force fluctuation can be suppressed and pedal feel can be secured.
On the other hand, in the area where the piston opens the reservoir port, the amount of regenerative energy recovered is ensured by setting the gradient of regenerative braking torque to be relatively steep compared to when the gradient is relatively gentle. it can.
Therefore, it is possible to provide a vehicular braking control device that can secure a recovered amount of regenerative energy while ensuring a good pedal feel by suppressing fluctuations in piston reaction force.

1 is an overall system diagram showing a configuration of an electric vehicle to which a vehicle brake control device of Embodiment 1 is applied. 1 is an overall block diagram illustrating a control system of a vehicle brake control device according to a first embodiment. FIG. 2 is a brake hydraulic pressure circuit diagram showing a VDC brake unit in the vehicle brake control device of the first embodiment. FIG. 3 is a mechanism explanatory diagram showing a relationship between a pedal stroke and a master cylinder hydraulic pressure in the vehicle brake control device of the first embodiment. It is a braking torque characteristic figure which shows the relationship between the driver request | requirement braking torque and master cylinder hydraulic pressure according to a pedal stroke (braking operation state). FIG. 6 is a braking torque characteristic diagram showing a relationship among an operation response braking torque, a pump-up braking torque, and a regenerative braking torque in the total braking torque. 3 is a flowchart showing a flow of braking control executed by an integrated controller, a brake controller, and a motor controller in the vehicle braking control apparatus of the first embodiment. 3 is a flowchart showing a flow of a gradient setting process executed by an integrated controller in the vehicle brake control device of the first embodiment. 6 is a time chart for explaining gradient setting of regenerative braking torque at the time of replacement control in the vehicle brake control device of the first embodiment. 3 is a time chart illustrating an operation example of the vehicle brake control device according to the first embodiment. 6 is a flowchart showing a flow of a gradient setting process that is executed by an integrated controller in the vehicle brake control device of the second embodiment. 6 is a flowchart showing a flow of a gradient setting process that is executed by an integrated controller in the vehicle brake control device of the second embodiment.

Hereinafter, the best mode for realizing the vehicle brake control device of the present invention will be described based on the first embodiment shown in the drawings.
First, the configuration of the vehicle brake control device of the first embodiment will be described.
The configuration of the vehicle brake control device according to the first embodiment will be described by dividing it into “entire system configuration”, “hydraulic brake device”, “regenerative brake device”, “control system”, “VDC brake unit configuration”, and “master cylinder configuration”. .

[Overall system configuration]
FIG. 1 shows a configuration of an electric vehicle driven by front wheels to which the vehicle braking control device of the first embodiment is applied. Hereinafter, the overall configuration of the vehicle brake control device will be described with reference to FIG.

The braking torque generation system of the vehicle braking control device according to the first embodiment includes a hydraulic braking device 1 and a regenerative braking device 50.
[Hydraulic braking device]
The hydraulic braking device 1 includes a master cylinder hydraulic pressure generating device 10, a VDC brake unit 2 that is an existing VDC system (VDC is an abbreviation of “Vehicle Dynamics Control”), a left front wheel wheel cylinder 4FL, and a right front wheel wheel. A cylinder 4FR, a left rear wheel wheel cylinder 4RL, and a right rear wheel wheel cylinder 4RR are provided.

  The master cylinder hydraulic pressure generator 10 is applied to each of the front and rear wheels (the left front wheel FLW, the right front wheel FRW, the left rear wheel RLW, and the right rear wheel RRW) in order to generate a friction braking torque in accordance with a braking operation by the driver. Generate master cylinder hydraulic pressure. The master cylinder hydraulic pressure generator 10 includes a brake pedal 15, an electric booster 12, a master cylinder 13, and a reservoir 14. That is, the driver's brake depression force applied to the brake pedal 15 is boosted by the electric booster 12, and the master cylinder hydraulic pressure (primary hydraulic pressure and secondary hydraulic pressure) is generated by the primary piston and the secondary piston of the master cylinder 13. The master cylinder hydraulic pressure is detected by a master cylinder hydraulic pressure sensor 16 described later.

  The VDC brake unit 2 performs vehicle behavior control (= VDC control) that prevents skidding and ensures excellent running stability when the vehicle posture is disturbed due to high-speed corner entry or sudden steering operation.

The VDC brake unit 2 is disposed in a hydraulic system that connects the master cylinder hydraulic pressure generator 10 and the wheel cylinders 4FL, 4FR, 4RL, and 4RR.
The VDC brake unit 2 includes hydraulic pumps 22 and 22 (see FIG. 3) that are driven by a VDC motor 21 (see FIG. 3), and controls increasing, holding, and reducing the pressure of the wheel cylinder hydraulic pressure Pwc. The VDC brake unit 2 and the master cylinder hydraulic pressure generator 10 are connected by a primary brake circuit 61 and a secondary brake circuit 62. The VDC brake unit 2 and each wheel cylinder 4FL, 4FR, 4RL, 4RR are connected by a left front wheel hydraulic pipe 63, a right front wheel hydraulic pipe 64, a left rear wheel hydraulic pipe 65, and a right rear wheel hydraulic pipe 66.

  The wheel cylinders 4FL, 4FR, 4RL, and 4RR are set on the brake disks of the front and rear wheels FLW, FRW, RLW, and RRW, and the hydraulic pressure from the VDC brake unit 2 is applied. The VDC brake unit 2 applies friction braking torque to the front and rear wheels by clamping the brake disc with the brake pad when the hydraulic pressure is applied to the wheel cylinders 4FL, 4FR, 4RL, 4RR. Further, the VDC brake unit 2 is so-called when the wheels FLW, FRW, RLW, RRW slip during braking to reduce the hydraulic pressure of the wheel cylinders 4FL, 4FR, 4RL, 4RR to suppress the lock. ABS (Antilock Brake System) control can also be executed.

[Regenerative braking device]
The regenerative braking device 50 includes a traveling electric motor 5.
The traveling electric motor 5 is provided as a traveling drive source for the left and right front wheels (drive wheels) FLW and FRW, and has a drive motor function and a power generator function. The electric motor 5 for traveling transmits driving force to the left and right front wheels (drive wheels) FLW and FRW by driving the motor while sucking and consuming battery power during power running. During regeneration, a load is applied to the rotational drive of the left and right front wheels to convert it into electric energy, and the generated power is charged into the battery 30 via the inverter 104 and the DC / DC junction box 105. That is, the load applied to the rotational driving of the left and right front wheels (drive wheels) FLW and FRW is the regenerative braking torque.
Therefore, the regenerative braking device 50 is constituted by the electric motor 5 for traveling and the motor controller 103 shown in FIG. 2 for controlling the regenerative braking torque. The traveling electric motor 5 is controlled by applying a three-phase alternating current generated by the inverter 104 based on a control command from the motor controller 103.

[Control system]
The braking torque control system of the vehicle braking control apparatus according to the first embodiment includes an integrated controller (VCM) 100, a brake controller 101, and a motor controller 103 shown in FIG.

The integrated controller 100 performs EV system start and stop control, driving force calculation and motor output command, deceleration force calculation, motor / brake output command, EV system diagnosis, fail-safe function, and the like.
Further, the integrated controller 100 integrates and controls the brake controller 101 and the motor controller 103 so as to obtain the driver requested braking torque at the time of regenerative cooperative brake control or the like. The integrated controller 100 includes battery charge capacity information from the battery controller 102, vehicle speed information from the wheel speed sensor 92, braking operation information from the brake switch 93, pedal stroke information for the brake pedal 15 from the pedal stroke sensor 94, master Master cylinder hydraulic pressure information from the cylinder hydraulic pressure sensor 16 is input. As the wheel speed sensor 92, a wheel speed rotation number sensor capable of detecting a vehicle speed up to an extremely low vehicle speed range is used. And real deceleration is calculated | required by carrying out time differentiation calculation processing of the wheel speed rotation speed.

  The brake controller 101 inputs a signal from the integrated controller 100 and pressure information from the master cylinder hydraulic pressure sensor 16 of the VDC brake unit 2. Then, in accordance with a predetermined control law, a drive command is output to the VDC motor 21 of the VDC brake unit 2 and the valves 25, 26, 27, and 28 shown in FIG. The target value of cooperative braking torque is output.

  The motor controller 103 is connected via an inverter 104 to the traveling electric motor 5 connected to the left and right front wheels FLW and FRW as drive wheels (see FIG. 1). When a regenerative command is input from the integrated controller 100 during braking control, the regenerative braking torque generated by the traveling electric motor 5 is controlled according to the input regenerative command. The motor controller 103 also has a function of controlling the motor torque and the motor rotation speed generated by the traveling electric motor 5 according to the traveling state and the vehicle state during traveling.

  Note that an inverter 104 and a charger 106 are connected to the battery 30 via a DC / DC junction box 105. In addition, a charging port 106 a is connected to the charger 106.

  The sensor group 90 includes the master cylinder hydraulic pressure sensor 16, wheel speed sensor 92, brake switch 93, pedal stroke sensor 94, accelerator pedal switch 95, yaw rate / lateral / front / rear acceleration sensor 96, steering angle sensor 97, etc. Is provided. The controllers 100 to 103 are connected to each other via a CAN communication line 100c so that they can communicate with each other. Although the sensor group 90 is illustrated as being directly connected to the integrated controller 100 in the figure, each sensor of the sensor group 90 is connected to the integrated controller 100 via the CAN communication line 100c and the controllers 101 to 103. The one connected to is also included.

[VDC brake unit configuration]
FIG. 3 is a brake hydraulic circuit diagram showing the VDC brake unit 2. The VDC brake unit 2 has a well-known configuration and will be described briefly.

  The VDC brake unit 2 controls the wheel cylinder hydraulic pressure Pwc based on a command from the brake controller 101 (see FIG. 2). The VDC brake unit 2 includes a VDC motor 21, hydraulic pumps 22 and 22 driven by the VDC motor 21, low pressure reservoirs 23 and 23, and a master cylinder hydraulic pressure sensor 16. The VDC brake unit 2 includes, as solenoid valves, a first M / C cut solenoid valve 25, a second M / C cut solenoid valve 26, holding solenoid valves 27, 27, 27, 27, and a pressure reducing solenoid valve 28. , 28, 28, 28.

  The first M / C cut solenoid valve 25 and the second M / C cut solenoid valve 26 are normally open solenoid valves that are closed during driving. Both cut solenoid valves 25, 26 shut off the primary brake circuit 61 and the secondary brake circuit 62 when the pump is driven by the VDC motor 21, and the difference between the wheel cylinder hydraulic pressure Pwc (downstream pressure) and the master cylinder pressure Pmc (upstream pressure). The pressure (= pump-up fluid pressure) is controlled. Both cut solenoid valves 25, 26 are provided with check valves 25a, 26a that allow the brake fluid to return from the wheel cylinders 4FL, 4FR, 4RL, 4RR to the master cylinder 13 when the valves are closed.

  The holding solenoid valves 27, 27, 27, 27 (IN valves) are normally open solenoid valves that are closed when driven, and the wheel cylinder hydraulic pressure to each of the wheel cylinders 4FL, 4FR, 4RL, 4RR by closing. Hold Pwc.

  The pressure-reducing solenoid valves 28, 28, 28, 28 (OUT valves) are normally closed solenoid valves that are opened during driving, and the wheel cylinder hydraulic pressures to the wheel cylinders 4FL, 4FR, 4RL, 4RR are opened by opening the valves. Pwc is released to the low-pressure reservoir 23 to reduce the pressure.

  Thus, by independently controlling the open / closed states of the holding solenoid valve 27 and the pressure reducing solenoid valve 28, the wheel cylinder hydraulic pressure Pwc to each wheel cylinder 4FL, 4FR, 4RL, 4RR is controlled independently for each wheel. Thereby, the VDC brake unit 2 performs so-called VDC control, TCS control, ABS control, regenerative cooperative brake control, front and rear wheel braking torque distribution control, and the like.

  FIG. 3 shows a state when the wheel cylinders 4FL, 4FR, 4RL, and 4RR are pressurized, and the valves 25, 26, 27, and 28 are in an inoperative state. At the time of this pressure increase, the master cylinder pressure Pmc and / or the pump pressure can be supplied to each wheel cylinder 4FL, 4FR, 4RL, 4RR to increase the pressure. When the pressure is increased by the pump pressure, both cut solenoid valves 25 and 26 are closed.

  When the wheel cylinder fluid pressure Pwc is held in each wheel cylinder 4FL, 4FR, 4RL, 4RR, the holding solenoid valve 27 connected to each wheel cylinder 4FL, 4FR, 4RL, 4RR to be held is energized and closed. Let In this case, the wheel cylinder hydraulic pressure Pwc is confined between the holding solenoid valve 27 and the pressure reducing solenoid valve 28 in the closed state, and the wheel cylinder hydraulic pressure Pwc is held.

  Further, when each wheel cylinder hydraulic pressure Pwc is reduced, the holding solenoid valve 27 connected to each wheel cylinder 4FL, 4FR, 4RL, 4RR to be reduced is energized and closed, and the depressurization solenoid valve 28 is energized. Open the valve. In this case, the wheel cylinder hydraulic pressure Pwc is shut off from the master cylinder 13 side by the holding solenoid valve 27 in the closed state, and is communicated to the low pressure reservoir 23 side through the pressure reducing solenoid valve 28 in the opened state. Is done.

  As described above, the wheel cylinder hydraulic pressure Pwc to the wheel cylinders 4FL, 4FR, 4RL, and 4RR is independently controlled as described above by independently controlling the pressure increase, holding, and pressure reduction in each wheel. can do.

  Further, as described in Patent Document 1, the low-pressure reservoir 23 is provided with a push rod 23b that can push up the check ball 23a when the amount of stored brake fluid is less than a predetermined value. ing. Therefore, when the hydraulic pump 22 is driven in a state where no brake fluid is stored in the low-pressure reservoir 23, the hydraulic pump 22 is connected to the master cylinder 13 via the brake circuits 61 and 62 and the return circuits 67 and 67. Brake fluid can be inhaled.

[Master cylinder configuration]
Here, the configuration of the master cylinder 13 will be described.
The master cylinder 13 communicates with the reservoir 14 via the reservoir port 13a shown in FIG. Therefore, when the brake pedal 15 is depressed, the piston 13b interlocked therewith strokes toward the back side of the master cylinder 13 and the reservoir port 13a is blocked, so that the master cylinder pressure Pmc corresponding to the braking operation is increased. It comes to stand up. Therefore, the limiting means is configured based on the arrangement of the master cylinder 13 and the reservoir port 13a.

  In FIG. 4, the position of the piston 13 b corresponding to the primary piston indicated by the solid line is the initial position ST <b> 0 when the braking operation of the brake pedal 15 is started. On the other hand, the position of the piston 13b indicated by a two-dot chain line in FIG. 4 is a reservoir port closed position STlim that completely closes the reservoir port 13a.

Therefore, in the first embodiment, when the brake pedal 15 is depressed, the pedal stroke (= piston stroke) is limited in the generation of the master cylinder pressure Pmc from the initial position ST0 to the reservoir port closed position STlim (the first embodiment). Then, it is limited to 0). Hereinafter, a region where the generation of the master cylinder pressure Pmc from the initial position ST0 to the reservoir port closed position STlim is limited is referred to as a hydraulic pressure generation suppression region LT.
Further, as shown in the braking torque characteristic diagram of FIG. 5, the master cylinder pressure Pmc rises when the pedal stroke (= piston stroke) exceeds the reservoir port closing position STlim and enters the non-hydraulic pressure generation suppression region. The generation suppression of the master cylinder pressure Pmc can be significantly performed when the pedal stroke speed is relatively low and the brake fluid flows in the reservoir port 13a. On the other hand, when the pedal stroke speed becomes relatively high, the liquid flow in the reservoir port 13a is limited, and the above-described suppression of the generation of the hydraulic pressure is suppressed, and the master cylinder pressure Pmc is generated even in the hydraulic pressure generation suppression region LT. There is also.

  The integrated controller 100, the brake controller 101, and the motor controller 103 execute control for generating a braking torque in accordance with the driver requested braking torque. This control will be described below.

[Brake control]
FIG. 7 shows a flow of braking control executed by the integrated controller 100, the brake controller 101, and the motor controller 103 in the vehicle braking control apparatus of the first embodiment. In this braking control, the total braking torque is controlled by coordinating the regenerative braking torque with the master cylinder pressure Pmc and the hydraulic braking torque based on the pump-up hydraulic pressure, and the braking operation is detected by the input from the brake switch 93. Will be started.

In step S1, the stroke signal from the pedal stroke sensor 94 and the master cylinder pressure Pmc from the master cylinder hydraulic pressure sensor 16 are read, and the driver requested braking torque is obtained based on this.
In step S <b> 2, regeneration is performed based on battery information such as battery charge capacity (battery SOC (abbreviation of “State Of Charge”)) based on the battery voltage and battery temperature from the battery controller 102, and vehicle speed information from the wheel speed sensor 92. It is determined whether braking is possible. If regenerative braking is possible, the process proceeds to step S3. If regenerative braking is not possible, the process proceeds to step S6. When regenerative braking is impossible, for example, when the battery SOC is in a fully charged state exceeding the upper limit value, when the battery temperature is higher than a preset upper limit temperature, or when the vehicle speed is lower than the set vehicle speed range Is also low or high.

In step S3 which proceeds when it is determined in step S2 that regenerative braking is possible, the target regenerative braking torque is calculated based on the vehicle speed or the like, and then the process proceeds to step S4.
In step S4, the pump-up braking torque necessary for obtaining the driver required braking torque obtained in step S1 is obtained, and then the process proceeds to step S5. Here, the pump-up braking torque is a value obtained by subtracting the target regenerative braking torque and the braking torque obtained from the master cylinder pressure Pmc actually generated by the braking operation from the driver requested braking torque.
In step S5, a target regenerative braking torque is generated by regenerative power generation of the traveling electric motor 5 based on the control of the motor controller 103, and if necessary, a pump-up braking torque is generated by the VDC brake unit 2, and one time Finish the process.

  On the other hand, in step S6 which proceeds when it is determined in step S2 that regeneration is impossible (NO), the pump-up braking torque is calculated, and then the process proceeds to step S7. In this step S6, the pump-up braking torque is a value obtained by subtracting the braking torque obtained from the master cylinder pressure Pmc from the driver request braking torque.

The above-described regenerative braking torque, pump-up braking torque, and total braking torque based on hydraulic braking torque based on the master cylinder pressure Pmc have the characteristics shown in FIG.
In the hydraulic pressure generation suppression region LT until the piston 13b reaches the reservoir port closing position STlim with the pedal stroke and the reservoir port 13a is closed, the total braking torque is secured by the regenerative braking torque and the pump-up braking torque. The total braking torque when the master cylinder pressure Pmc = 0 is set as the base braking torque. Note that this base braking torque corresponds to the master cylinder pressure Pmc when the piston 13b reaches the reservoir port closing position STlim in the master cylinder configured to close the reservoir port 13a when the stroke of the piston 13b starts.
Then, when the piston 13b reaches the reservoir port closing position STlim and the master cylinder pressure Pmc rises, the operation-corresponding braking torque by the master cylinder pressure Pmc is added to the base braking torque so far.

  Thereafter, when the vehicle speed decreases due to the braking operation, it becomes difficult to obtain the regenerative braking torque. Therefore, the switching control is performed to increase the distribution of the pump-up braking torque while reducing the distribution of the regenerative braking torque in the base braking torque.

  In addition to the case where the vehicle speed falls below the set vehicle speed as described above, the above-described braking torque replacement is performed when the slip ratio of the drive wheels (the left and right front wheels FLW and FRW) exceeds a preset slip threshold. Also do it.

[Slope setting processing]
Next, a gradient setting process for setting an increase gradient and a decrease gradient when increasing or decreasing the regenerative braking torque when determining the regenerative braking torque in step S3 will be described.
First, a basic setting method for the regenerative braking torque increase gradient (θup in FIG. 6) and decrease gradient (θdwn in FIG. 6) will be described.
When the braking operation is started, according to the vehicle deceleration estimated by the braking operation, the increasing gradient θup is set gradually as the deceleration increases, and the increasing gradient θup is set suddenly as the deceleration decreases.

Further, when the regenerative braking torque and the hydraulic braking torque are switched when the vehicle speed decreases to the set vehicle speed, the pump-up braking torque is increased as the regenerative braking torque decreases, as shown in FIG. . At that time, since the increase in the hydraulic braking torque causes a response delay as shown by the dotted line in the figure, the response delay of the hydraulic braking torque as shown by the dotted line with respect to the regenerative braking torque. The regenerative braking torque decreasing gradient θdwn according to the above is set.
As a result, when the regenerative braking torque is not considered in response to the hydraulic braking torque, as shown by the solid line in the figure, it is possible to suppress the reduction in deceleration as shown by the dotted line in the figure.

Further, in the present embodiment, a gradient setting process is performed in which the regenerative braking torque increase gradient θup and decrease gradient θdwn are set according to the pedal stroke amount Sp of the brake pedal 15 (stroke position of the piston 13b).
Below, the flow of this gradient setting process is demonstrated based on the flowchart of FIG.
In step S31, it is determined whether or not the pedal stroke amount Sp is less than a stroke threshold value Sres corresponding to the reservoir port closing position STlim. If Sp <Sres, the process proceeds to step S32. If Sp ≧ Sres, the process proceeds to step S35.

  In step S32, it is determined whether or not the master cylinder pressure Pmc is less than a corresponding master cylinder threshold value Pres when the reservoir port closing position STlim of the piston 13b is reached. If Pmc <Pres, the process proceeds to step S33, and if Pmc ≧ Pres, the process proceeds to step S34.

  In the case of Sp <Sres and Pmc <Pres, that is, when the piston 13b is surely present in the region where the reservoir port 13a is opened, the step S33 proceeds as the second increase / decrease gradient ΔT2 as the increase / decrease gradient ΔTreg of the regenerative braking torque. Select. The increase / decrease gradient ΔTreg serves as both the increase gradient θup and the decrease gradient θdwn described above. In addition, the second increase / decrease gradient ΔT2 is set to be relatively steeper than a later-described first increase / decrease gradient ΔT1 (see FIG. 10).

  In step S35 that proceeds when Sp ≧ Sres in step S31 and step S34 that proceeds when Pmc ≧ Pres in step S32, the first increase / decrease gradient ΔT1 is selected as the increase / decrease gradient ΔTreg of the regenerative braking torque. The first increase / decrease gradient ΔT1 is set to a relatively steep gradient than the second increase / decrease gradient ΔT2.

(Operation of Embodiment 1)
Next, operation examples of the vehicle brake control device and the comparative example of the first embodiment will be described based on a time chart.

First, the subject of the comparative example which does not perform the change gradient setting process of regenerative braking torque is demonstrated based on FIG.
At the time of regenerative cooperative braking control, as shown in FIG. 6, the total braking torque determined according to the braking operation is formed by the regenerative braking torque and the hydraulic braking torque. Further, until the piston 13b reaches the reservoir port closing position STlim, the hydraulic braking torque is formed by the pump-up braking torque by the VDC brake unit 2.
In the comparative example, the increase gradient θup and the decrease gradient θdwn of the regenerative braking torque are controlled to be constant regardless of the position of the piston 13b (pedal stroke amount Sp).

As described above, when the gradients θup and θdwn are set to be constant, if the setting is relatively steep, the pedaling force fluctuation of the brake pedal 15 becomes large, which may cause the driver to feel uncomfortable.
That is, in the time chart shown in FIG. 6, the switching control for increasing the pump-up braking torque is performed from the time t01 while reducing the regenerative braking torque. When the pump-up braking torque is generated from the time t01, the piston 13b closes the reservoir port 13a, and the hydraulic pump 22 needs to suck in the brake fluid from the master cylinder 13 side in the closed space state. . Therefore, when the brake fluid is sucked from the master cylinder 13, the master cylinder pressure Pmc varies, and thereby the pedal reaction force also varies, which may cause the driver to feel uncomfortable. At this time, if the decrease gradient θdwn of the regenerative braking torque is steep, the pump-up braking torque also increases steeply and the pedal reaction force fluctuation increases, which may give the driver a sense of incongruity.

On the other hand, in order to suppress such pedal reaction force fluctuations, it is conceivable to reduce the regenerative braking torque decrease gradient θdwn. That is, when the decrease gradient θdwn is made gentle, the fluctuation amount of the pump-up braking torque is also suppressed, and the fluctuation amount per unit time of the master cylinder pressure Pmc is also suppressed. Therefore, the pedal reaction force felt by the driver can also be suppressed from causing a sense of incongruity because the fluctuation amount per unit time is suppressed.
However, in this case, the amount of regenerative energy that can be recovered is reduced as compared with the case where the decrease gradient is made steep because the decrease gradient of the regenerative braking torque is made gentle.
As described above, in the comparative example, it was difficult to secure the recovered amount of regenerative energy while suppressing the piston reaction force fluctuation and securing a good pedal feel.

(Operation example of Embodiment 1)
The vehicular braking control apparatus according to Embodiment 1 solves the problem of the comparative example, and suppresses a decrease in the amount of regenerative energy that can be recovered while suppressing fluctuations in pedal reaction force so as not to give the driver a sense of incongruity. It is.

An example of the operation will be described below with reference to the time chart of FIG.
When the braking operation is performed (at time t0), after calculating the driver required braking torque (S1 in FIG. 7), if the regenerative braking is possible, the calculated regenerative braking torque and the pump-up braking torque (FIG. 7). S3, S4), the regenerative braking torque and the pump-up braking torque are started up.

  At time t1, the piston 13b closes (or narrows) the reservoir port 13a, the master cylinder pressure Pmc rises, and the hydraulic braking torque is formed by the pump-up braking torque and the master cylinder pressure Pmc. .

At this time, in the first embodiment, the increasing / decreasing gradient of the regenerative braking torque is set to either the first increasing / decreasing gradient ΔT1 or the second increasing / decreasing gradient ΔT2 based on the pedal stroke amount Sp and the master cylinder pressure Pmc. The
That is, the increase gradient θup of the regenerative braking torque is set to the second increase / decrease gradient ΔT2 from the time t0 when the braking starts to the time t1 when the piston 13b opens the reservoir port 13a and the master cylinder pressure Pmc rises. From the time t1 when the piston 13b closes the reservoir port 13a and the master cylinder pressure Pmc rises to the time t2 when the regenerative braking torque reaches the base braking torque, the increase gradient θup of the regenerative braking torque is the first increase / decrease gradient ΔT1. Set to
Therefore, from the time point t0 when braking starts until the time point t1 when the master cylinder pressure Pmc rises, the regenerative braking torque distribution is increased in the total braking torque, compared with the case where the first increase / decrease gradient ΔT1 is set. The amount of energy recovered can be secured.

  Thereafter, after the piston 13b exceeds the reservoir port closing position STlim and closes the reservoir port 13a, the increase / decrease gradient ΔTreg is set to the second increase / decrease gradient ΔT1. Thereby, the fluctuation amount per unit time of the regenerative braking torque is suppressed, and accordingly, the fluctuation amount of the pump-up braking torque is also suppressed.

Thereafter, the vehicle speed decreases, and replacement control is started at time t3. During this switching control, the brake pedal 15 remains depressed, the piston 13b closes the reservoir port 13a, and the master cylinder pressure Pmc is also generated, so the increase gradient θup of the regenerative braking torque is The first increase / decrease gradient ΔT1 is set.
During this switching control, the VDC brake unit 2 drives the hydraulic pump 22 to increase the wheel cylinder pressure. At this time, the brake fluid that can be sucked is closed on the brake circuits 61 and 62 side of the master cylinder 13. Brake fluid in the space. Therefore, as described in the comparative example, when the brake fluid on the master cylinder 13 side is sucked by the hydraulic pump 22, the master cylinder pressure Pmc varies.
However, since the first increase / decrease gradient ΔT1 is used as the decrease gradient θdwn of the regenerative braking torque, the fluctuation amount per unit time of the master cylinder pressure Pmc can be suppressed as compared with the case where the second increase / decrease gradient ΔT2 is used. it can. Thereby, the pedal reaction force can also suppress the fluctuation amount per unit time, and can suppress the uncomfortable feeling given to the driver.

(Effect of Embodiment 1)
The effects of the vehicle brake control device according to the first embodiment are listed below.
1) The vehicle braking control apparatus of Embodiment 1
The master cylinder pressure Pmc generated according to the piston stroke by the braking operation can be supplied to the wheel cylinders 4FL to 4RR, and the pedal stroke amount Sp as the piston stroke amount is determined from the initial position ST0 at the start of the braking operation to the master cylinder 13. In the region until the reservoir port 13a communicating with the reservoir 14 is closed, the increase in the master cylinder pressure Pmc is suppressed, and the pedal stroke amount Sp is determined according to the braking operation in the region where the reservoir port 13a is closed. A hydraulic braking device 1 in which Pmc rises;
VDC as a pump-up hydraulic pressure generating device that is disposed in both brake circuits 61 and 62 as hydraulic circuits for connecting the master cylinder 13 and the wheel cylinders 4FL to 4RR and supplies pump-up hydraulic pressure to the wheel cylinders 4FL to 4RR. Brake unit 2,
A regenerative braking device 50 that is provided in a drive system of the vehicle and generates a regenerative braking force;
A pedal stroke sensor 94 as a braking operation state detection device for detecting the braking operation state;
An integrated controller 100 as a braking control controller that controls the total braking torque by executing regenerative cooperative control that coordinates the regenerative braking torque with the hydraulic braking torque by the master cylinder pressure Pmc and the pump-up hydraulic pressure according to the braking operation state. When,
In a vehicle brake control device comprising:
The integrated controller 100 as the braking control controller determines that at least one of the increasing gradient θup and decreasing gradient θdwn of the regenerative braking torque at the time of the regenerative cooperative control is that the reservoir port 13a is open. In the region, a regenerative torque increase / decrease gradient setting unit for performing a gradient setting process (the process shown in the flowchart of FIG. 8) for setting a steeper gradient than the region where it is determined that the reservoir port 13a is closed is provided. .
Therefore, at least one of the increase and decrease of the regenerative braking torque makes the increase / decrease gradient (ΔTreg) of the regenerative braking torque relatively gentle in the region where the piston 13b closes the reservoir port 13a. Thereby, compared with the case where the fluctuation | variation gradient of regenerative braking torque is made comparatively steep, a piston reaction force fluctuation | variation can be suppressed and a pedal feel can be ensured.
On the other hand, in the region where the piston 13b opens the reservoir port 13a, the regenerative energy is increased compared with the case where the gradient is relatively gentle by setting the increase / decrease gradient (ΔTreg) of the regenerative braking torque relatively steeply. Can be secured.
Therefore, the recovery amount of regenerative energy can be ensured while suppressing the piston reaction force fluctuation and ensuring a good pedal feel.

2) The vehicle braking control device of the first embodiment is
The regenerative torque increase / decrease gradient setting unit executes the gradient setting process for both the increase gradient θup and the decrease gradient θdwn.
Therefore, the effect 1) can be obtained in both cases where the regenerative braking torque is increased and decreased.

3) The vehicle braking control device of the first embodiment is
A pedal stroke sensor 94 as a stroke amount detection device for detecting the piston stroke amount (Sp), and a master cylinder hydraulic pressure sensor 16 as a master cylinder pressure detection device for detecting the master cylinder pressure Pmc;
Based on the piston stroke amount (Sp) and the master cylinder pressure Pmc, the regenerative torque increase / decrease gradient setting unit causes both the detected stroke amount (Sp) and the detected master cylinder pressure (P) to open the reservoir port. In the case shown (Sp <Sres, P <Pres), it is determined that the reservoir port 13a is open, and otherwise, it is determined that the reservoir port 13a is closed.
Therefore, even when the change in the master cylinder pressure Pmc is delayed with respect to the pedal stroke amount Sp, it is possible to appropriately set the pressure increasing / decreasing gradient corresponding to the piston position without delay in response based on the pedal stroke amount. it can.
On the other hand, when the pedal stroke speed is high, the master cylinder pressure Pmc rises before the piston 13b actually closes the reservoir port 13a, and the pedal reaction force may vary during pump-up. In such a case, the pedal reaction force fluctuation can be suppressed by setting an increasing / decreasing gradient according to the reservoir port closing position at an early stage based on the master cylinder pressure Pmc.

(Other embodiments)
Next, a vehicle brake control device according to another embodiment will be described.
Since the other embodiment is a modification of the first embodiment, the same reference numerals as those in the first embodiment are assigned to the same components as those in the first embodiment, and the description thereof is omitted. Only the differences will be described.

(Embodiment 2)
Next, a vehicle brake control device according to Embodiment 2 will be described.
In the second embodiment, the determination of the reservoir port closed position is performed based on the piston stroke amount (pedal stroke amount Sp) and the master cylinder pressure Pmc in the first embodiment, whereas the piston stroke amount (pedal) In this example, only the stroke amount Sp) is used.
That is, FIG. 11 is a flowchart showing the gradient setting process in the second embodiment. As shown in this flowchart, when Sp <Sres in step S31, the process proceeds to step S33, and the increase / decrease gradient ΔTreg is set to the second increase / decrease gradient ΔT2. On the other hand, in step S <b> 34 that proceeds when Sp ≧ Sres in step S <b> 31, the increase / decrease gradient ΔTreg is set to the first increase / decrease gradient ΔT <b> 1.

  Therefore, in the second embodiment, based on the pedal stroke amount Sp, the piston position is set to the second increase / decrease gradient ΔT2 from the initial position ST0 to the reservoir port closed position STlim. On the other hand, when the pedal stroke amount Sp indicates that the piston position exceeds the reservoir port closing position STlim, the increase / decrease gradient ΔTreg is set to the first increase / decrease gradient ΔT1.

  Even in the above-described second embodiment, as described in the above 1) and 2) of the first embodiment, the same effect can be obtained based on the configuration. Further, the second embodiment has the effects described in the following 2-1).

2-1) The vehicular braking control apparatus according to the second embodiment is
A pedal stroke sensor 94 as a stroke amount detection device for detecting the piston stroke amount (Sp);
The regenerative torque increase / decrease gradient setting unit performs opening / closing determination of the reservoir port 13a based on a pedal stroke amount Sp as a piston stroke amount detected by the pedal stroke sensor 94.
Therefore, even when the change in the master cylinder pressure Pmc is delayed with respect to the pedal stroke amount Sp, it is possible to appropriately set the pressure increasing / decreasing gradient corresponding to the piston position without delay in response based on the pedal stroke amount. it can.

(Embodiment 3)
Next, a vehicle brake control device according to Embodiment 3 will be described.
The third embodiment is also a modification of the first embodiment, and is an example in which the determination of the reservoir port closed position is performed based only on the master cylinder pressure Pmc.
That is, FIG. 12 is a flowchart showing the gradient setting process in the third embodiment. As shown in this flowchart, if Pmc <Pres in step S32, the process proceeds to step S33, and the increase / decrease gradient ΔTreg is set to the second increase / decrease gradient ΔT2. On the other hand, in step S34 which proceeds when Pmc ≧ Pres in step S32, the increase / decrease gradient ΔTreg is set to the first increase / decrease gradient ΔT1.

  Therefore, in the third embodiment, when the master cylinder pressure Pmc indicates that the piston position is from the initial position ST0 to the reservoir port closed position STlim, the increase / decrease gradient ΔTreg is set to the second increase / decrease gradient ΔT2. On the other hand, when the master cylinder pressure Pmc indicates that the piston position exceeds the reservoir port closing position STlim, the increase / decrease gradient ΔTreg is set to the first increase / decrease gradient ΔT1.

  Even in the above-described third embodiment, as described in the above 1) and 2) of the first embodiment, the same effect can be obtained based on the configuration. Further, the third embodiment has the effects described in the following 3-1).

3-1) The vehicle brake control device of Embodiment 3 is
A master cylinder hydraulic pressure sensor 16 as a master cylinder pressure detecting device for detecting the master cylinder pressure Pmc;
The regenerative torque increase / decrease gradient setting unit performs opening / closing determination of the reservoir port 13a based on the master cylinder pressure Pmc.
Therefore, when the pedal stroke speed is high, the master cylinder pressure Pmc rises before the piston 13b actually closes the reservoir port 13a, and the pedal reaction force may vary when the pump is up. In such a case, the pedal reaction force fluctuation can be suppressed by setting an increasing / decreasing gradient according to the reservoir port closing position at an early stage based on the master cylinder pressure Pmc.

  As mentioned above, although the vehicle brake control apparatus of the present invention has been described based on the embodiment, the specific configuration is not limited to this embodiment, and the invention according to each claim of the claims. Design changes and additions are permitted without departing from the gist of the present invention.

For example, in the embodiment, an example in which the vehicle brake control device of the present invention is applied to a front-wheel drive electric vehicle has been described. However, the vehicle brake control device of the present invention is applied to a rear wheel drive, all-wheel drive electric vehicle, hybrid vehicle, or fuel cell vehicle as long as it is a vehicle that switches between regenerative braking torque and friction braking torque. You can also.
Further, in the embodiment, the master cylinder hydraulic pressure is limited to 0 when the restriction means restricts. However, at the time of restriction, the increase in the master cylinder hydraulic pressure is suppressed as compared with the non-restricted state. You may use what generate | occur | produces.
In the embodiment, the VDC brake unit is shown as the pump-up hydraulic pressure generating device, but the present invention is not limited to this. For example, an electric booster as disclosed in Japanese Patent Application Laid-Open No. 2010-179742 may be used to increase the pump-up pressure by a booster operation that drives the electric assist member.

1 Hydraulic braking device 2 VDC brake unit (pump-up hydraulic pressure generator)
4FL Left front wheel wheel cylinder 4FR Right front wheel wheel cylinder 4RL Left rear wheel wheel cylinder 4RR Right rear wheel wheel cylinder 13 Master cylinder 13a Reservoir port 13b Piston 14 Reservoir 50 Regenerative braking device 94 Pedal stroke sensor (braking operation state detection device)
100 integrated controller (braking control unit: regenerative braking torque increase / decrease gradient setting unit)
Pmc Master cylinder pressure Sp Pedal stroke amount (piston stroke amount)
STlim reservoir port closed position ΔT1 first increasing / decreasing gradient ΔT2 second increasing / decreasing gradient ΔTreg increasing / decreasing gradient θdwn decreasing gradient θup increasing gradient

Claims (5)

The master cylinder pressure generated according to the piston stroke caused by the braking operation can be supplied to the wheel cylinder, and the reservoir port that connects the master cylinder and the reservoir from the initial position when the piston stroke amount starts the braking operation is closed. A hydraulic brake device in which an increase in the master cylinder pressure is suppressed in a region until the operation is performed, and the piston stroke amount is increased in the region where the reservoir port is closed in accordance with the braking operation;
A pump-up hydraulic pressure generator that is arranged in a hydraulic circuit that connects the master cylinder and the wheel cylinder, and supplies pump-up hydraulic pressure to the wheel cylinder;
A regenerative braking device that is provided in a drive system of the vehicle and generates a regenerative braking force;
A braking operation state detection device for detecting the braking operation state;
A braking control controller that controls the total braking torque by executing regenerative cooperative control in which the regenerative braking torque and the hydraulic brake torque by the master cylinder pressure and the pump-up hydraulic pressure are coordinated according to the braking operation state;
In a vehicle brake control device comprising:
The brake controller, the increase gradient of the regenerative braking torque during the regeneration coordination control in a region where the reservoir port is determined to be opened, from a region where the reservoir port is determined to be closed A braking control device for a vehicle, further comprising a regenerative torque increase / decrease gradient setting unit for performing gradient setting processing for setting a steep gradient. The vehicle brake control device according to claim 1,
The regenerative torque increase / decrease gradient setting unit executes the gradient setting process for both the increase gradient and the decrease gradient. In the vehicle brake control device according to claim 1 or 2,
A stroke amount detection device for detecting the piston stroke amount;
The regenerative torque increase / decrease gradient setting unit performs opening / closing determination of the reservoir port based on a piston stroke amount detected by the stroke amount detection device. In the vehicle brake control device according to claim 1 or 2,
A master cylinder pressure detecting device for detecting the master cylinder pressure;
The regenerative torque increase / decrease gradient setting unit performs opening / closing determination of the reservoir port based on the master cylinder pressure. In the vehicle brake control device according to claim 1 or 2,
A stroke amount detection device for detecting the piston stroke amount, and a master cylinder pressure detection device for detecting the master cylinder pressure,
Based on the piston stroke amount and the master cylinder pressure, the regenerative torque increase / decrease gradient setting unit opens the reservoir port when both the detected stroke amount and the detected master cylinder pressure indicate that the reservoir port is open. It is determined that the reservoir port is closed, and otherwise, it is determined that the reservoir port is closed.