JP3412508B2 - Braking force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to a braking force control for a vehicle.
In particular, the hydraulic braking means and the regenerative braking means
The present invention relates to a braking force control device provided. [0002] 2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. 1, the hydraulic pressure for generating a hydraulic braking force
Braking means, and regenerative braking means for generating a regenerative braking force.
A known braking force control device is known. The hydraulic braking means
By supplying the required oil pressure to the
A hydraulic braking force corresponding to the cylinder pressure is generated. Also, times
The raw braking means is a circuit that is generated by rotation of the motor driven wheels.
A regenerative braking force is generated by raw energy. Hydraulic braking force
And the regenerative braking force, the sum of which is the braking required for the vehicle
Control force (hereinafter referred to as the required braking force).
It is. [0003] When the regenerative braking force is generated,
The corresponding regenerative energy is supplied to the battery as charging current.
Be paid. Therefore, it is important to maintain the state of charge of the battery.
From the point of view, it is possible to ensure maximum regenerative energy
It is advantageous to generate as much regenerative braking force as possible.
You. The maximum regenerative braking force that the regenerative braking means can generate (hereinafter
Below, called the maximum regenerative braking force) is the state of charge of the battery
It changes according to conditions, temperature, vehicle speed, and the like. Therefore, the maximum
When generating a regenerative braking force equal to the regenerative braking force, the maximum
When the regenerative braking force increases, the hydraulic control
Power must be reduced. [0004] Hydraulic braking means is operated by a wheel cylinder.
-Hydraulic fluid is drained to reduce hydraulic braking force
Let it. Outflow of brake fluid from wheel cylinder
The flow rate is controlled by the wheel cylinder pressure, flow path opening, etc.
Limited. Restriction of flow rate reduces hydraulic braking force
The maximum value of the gradient (hereinafter referred to as the maximum hydraulic pressure decrease gradient) is also constant.
It will be limited to below the value. For this reason, the maximum regeneration system
If the power suddenly increases, the oil will be sloped according to the increase.
A situation may occur in which the pressure braking force cannot be reduced.
When such a situation occurs, the sum of the regenerative braking force and the hydraulic braking force
Exceeds the required braking force, causing unnatural braking for the driver.
Gives a feeling. [0005] SUMMARY OF THE INVENTION To avoid the above disadvantages
Therefore, when the maximum regenerative braking force increases,
So that the increasing gradient does not exceed the hydraulic maximum decreasing gradient.
It is necessary to control. As mentioned above, maximum oil pressure reduction
The gradient changes according to the wheel cylinder pressure. Therefore,
To generate the maximum regenerative braking force, the maximum
Suppression of regenerative braking force increase gradient based on oil pressure decrease gradient
Needs to be kept to the minimum necessary range. However
However, in the conventional braking force control device described above,
Determines the regenerative braking force increase gradient based on the pressure maximum decrease gradient
The regenerative braking force
To avoid the above-mentioned inconveniences caused by the sudden increase,
The slope of the hydraulic braking force that can be
Minimum of hydraulic pressure decreasing gradient against surrounding wheel cylinder pressure
Value) to determine the increasing slope of the regenerative braking force.
is there. For this reason, according to the conventional braking force control device,
The gradient of increase in regenerative braking force is suppressed more than necessary,
It is difficult to maximize the energy. [0006] The present invention has been made in view of the above points.
Estimate the maximum decrease gradient of oil pressure at each point in time
By determining the increase gradient of the regenerative braking force based on
The sum of the hydraulic braking force and the regenerative braking force exceeds the required braking force
To maximize regenerative energy while preventing
It is an object of the present invention to provide a braking force control device capable of performing a braking operation. [0007] The above object is achieved by the present invention.
Hydraulic braking means for generating a hydraulic braking force as described in
Regenerative braking means for generating a regenerative braking force;
Cooperative control for cooperatively operating a moving means and the regenerative braking means
Means for controlling a braking force, comprising:
Means for estimating a maximum decreasing gradient of the hydraulic braking force;
A maximum decreasing gradient estimating means, and a hydraulic maximum decreasing gradient estimating means.
Based on the maximum decreasing slope estimated by the step,
Determination of the regenerative increase gradient that determines the upper limit of the braking force increase gradient
Means for controlling the braking force. [0008] In the present invention, the cooperative control means includes a hydraulic control unit.
It is provided with a large decrease gradient estimating means and a regeneration increasing gradient determining means.
You. The hydraulic pressure maximum gradient estimating means calculates the maximum reduction of the hydraulic braking force.
Estimate the minor gradient. The regenerative increase gradient determining means
Based on the maximum decreasing slope
Determine the limit. Therefore, the cooperative control means uses the regenerative braking force.
Range where the increasing gradient of the hydraulic braking force does not exceed the maximum decreasing gradient of the hydraulic braking force.
The hydraulic control hand while generating the maximum regenerative braking force
Cooperative control of the step and the regeneration control means can be performed. [0009] FIG. 1 shows a control system according to an embodiment of the present invention.
1 shows a system configuration diagram of a power control device. Braking of this embodiment
The force control device is an electronic control unit 10 for regenerative control
(Hereinafter referred to as regenerative ECU 10) and electronic control for brake control
The control unit 12 (hereinafter referred to as the brake ECU 12)
Have. The regenerative ECU 10 and the brake ECU 12
They are interconnected via communication lines. The regenerative ECU 10 includes a drive regenerative device 14.
It is connected. The drive regeneration device 14 includes a drive motor.
I have. In the system of this embodiment, the left and right front wheels F
L and FR are drive wheels and left and right rear wheels RR and RL are non-drive wheels.
Have been. FIG. 1 shows left and right front wheels FL and FR as drive wheels.
Only shows. Left and right front wheels FL, FR
Drive shafts 20 and 21 and a gear unit (not shown)
The rotor of the drive motor is connected via a structure. Follow
The front and rear wheels FL and FR have driveshafts respectively.
The driving force generated by the driving motor is transmitted through the shafts 20 and 21.
Is reached. A battery 24 is connected to the drive motor.
I have. The drive motor is provided with electric power supplied from the battery 24.
, And generates front and rear left and right wheels FL,
Regenerative energy using torque input from FR as power source
It has a function to generate Inside the drive motor
Is a magnetic field generating mechanism for generating a magnetic field of a predetermined strength, and
There is a built-in coil that rotates across the magnetic field.
The magnetic field generated by the magnetic field generation mechanism
It changes according to the command signal supplied from 0. Also, magnetic
The field and the coil rotate relatively as the wheel rotates. Large regenerative energy generated by the drive motor
The magnitude is the strength of the magnetic field generated by the magnetic field generation mechanism, and
And the relative rotational speed of the magnetic field and the coil,
The value corresponds to the wheel speed of the right front wheels FL and FR. Therefore,
The magnitude of the regenerative energy is supplied from the regenerative ECU 10.
Can be controlled according to the value of the command signal. Drive module
When the motor generates regenerative energy, the left and right front wheels FL,
The FR has a regenerative torque that attempts to brake that rotation.
To use. That is, the regenerative torque generated by the drive motor
Acts as a braking force on the left and right front wheels FL and FR.
You. Hereinafter, the braking force generated by the regenerative torque
Braking force F_GCalled. The regenerative energy generated by the drive motor is:
It is supplied to the battery 24 as a charging current. Follow
Therefore, the larger the regenerative torque is generated, the more the battery 24
Is charged with a large charging current. Battery 24 receives
The upper limit of regenerative energy that can be
4, limited by the state of charge and temperature. Also drive
The upper limit of the regenerative energy that the motor can generate is the left and right front wheels
It is limited by the wheel speed of FL and FR. Therefore, regeneration
Braking force F_GThe upper limit of the charge state of the battery 24, the temperature,
And is limited by the wheel speeds of the left and right front wheels FL and FR.
You. Hereinafter, the regenerative braking force F_GThe upper limit of the maximum regenerative braking force F
_GmaxCalled. The braking force control device of the present embodiment
A control mechanism 32 is provided. The hydraulic control mechanism 32 is a master
A cylinder 34 is provided. The master cylinder 34
A rake pedal 36 is connected. Master cylinder 3
4 corresponds to the operation amount applied to the brake pedal 36.
Hydraulic pressure (hereinafter master cylinder pressure P_{M / C}Occurs)
I do. The master cylinder 34 has a hydraulic actuator 38
Is connected. The hydraulic actuator 38 is a brake
It is connected to the ECU 12. Hydraulic actuator 38
According to a command signal given from the brake ECU 12
To generate brake oil pressure. Hydraulic actuator 38
, A wheel cylinder of each wheel communicates. Follow
In each wheel cylinder, a hydraulic actuator 38 is provided.
A hydraulic pressure according to the generated brake hydraulic pressure is supplied. [0015] The wheel cylinder is keyed by a force corresponding to the oil pressure.
The calipers 40 and 41 are driven. Calipers 40 and 41 drive
When actuated, brakes mounted on calipers 40 and 41
The pad is used for the hydraulic pressure of the wheel cylinder
Da pressure P_{W / C}The disk rotor 42 with a force corresponding to
43 is pressed toward the braking surface. Therefore, the brake E
In response to a command signal given from the CU 12 to the hydraulic control mechanism 32
A braking force of a corresponding magnitude is applied to each wheel. Hydraulic control
The braking force generated by the mechanism 32 is hereinafter referred to as a hydraulic braking force F._LWhen
Name. As described above, in the system of this embodiment,
Therefore, the drive regeneration device 14 is generated in the left and right wheels FL and FR.
Regenerative braking force F_GAnd the oil generated by the hydraulic control mechanism 32
Pressure braking force F_LAre both given. Also, left and right rear wheels R
L and RR have a hydraulic braking force F_LOnly is given. hydraulic
The actuator 38 detects a master cylinder pressure.
A star pressure sensor is provided. Output signal of master pressure sensor
Are supplied to the brake ECU 12. Brake E
The CU 12 controls the vehicle based on the output signal of the master pressure sensor.
The braking force to be generated in both, i.e. the required braking
Force F_REQIs calculated. Regenerative braking force F _GAnd hydraulic braking force F_L
Is the sum of them (hereinafter, the total braking force F_ALLRequired)
Braking force F_REQIs controlled to be equal to Next, referring to FIG.
Will be described. FIG. 2 is a configuration diagram of the hydraulic control mechanism 32.
It is. As shown in FIG. 2, the hydraulic control mechanism 32 includes a pump
46 is provided. Pump 46 is driven by motor 48
Is done. A reservoir tank 50 is provided at a suction port of the pump 46.
Communicating. The discharge port of the pump 46 is regulated.
A high-pressure passage 54 leading to the heater 52 is in communication. High pressure passage 5
An accumulator 56 communicates with 4. Accu
The murator 56 controls the brake fluid discharged from the pump 46.
To store. A main hydraulic passage 58 is connected to the regulator 52.
Through. The regulator 52 is supplied from the high pressure passage 54.
The supplied hydraulic pressure of the accumulator 56 is adjusted to a predetermined
Rator pressure P_REAnd output to the main hydraulic passage 58. main
The regulator pressure P_REDetecting hydraulic pressure
A sensor 60 and a pressure increase control valve 62 are provided.
You. The output signal of the oil pressure sensor 60 is sent to the brake ECU 12.
Supplied. The brake ECU 12 is provided with the hydraulic sensor 6
0 based on the output signal of the regulator._REDetect
You. The pressure increase control valve 62 is connected to the main hydraulic passage 58.
This is a linear control valve that changes the conduction state. Boosting system
The control valve 62 receives a drive signal supplied from the ECU 12.
The opening is changed accordingly. The main hydraulic passage 58
In parallel with the pressure control valve 62, downstream of the pressure increase control valve 62
Allows only fluid flow from regulator side to regulator 52 side.
A check valve 64 is provided. The main hydraulic passage 58 and the pressure increase control valve 62
On the downstream side, a decompression passage 6 leading to the auxiliary reservoir tank 66 is provided.
8 are in communication. The pressure reduction control valve 7 is provided in the pressure reduction passage 68.
0 is provided. The pressure-reducing control valve 70 is connected to a pressure-reducing passage
68 is a pressure reduction control valve mechanism for controlling the conduction state of 68.
The pressure reduction control valve 70 is supplied from the brake ECU 12.
The opening degree is changed according to the drive signal to be transmitted. Decompression passage
68 has an auxiliary reservoir in parallel with the pressure reducing control valve 70.
Fluid flow from tank 66 toward main hydraulic passage 58
A check valve 72 that allows only a check is provided. The main hydraulic passage 58 communicates with the pressure increase control valve 62.
On the downstream side, the wheel cylinder 7 on the rear wheel RL, RR side
4 and 76 are communicated with a rear wheel side hydraulic passage 78. rear
The oil inside the rear wheel side hydraulic passage 78 is supplied to the wheel side hydraulic passage 78.
Pressure, that is, rear wheel side brake oil pressure P_RDetecting hydraulic pressure
A sensor 80 is provided. Output signal of oil pressure sensor 80
The signal is supplied to the brake ECU 12. Brake E
The CU 12 controls the rear wheels based on the output signal of the hydraulic pressure sensor 80.
Side brake oil pressure P_RIs detected. The pressure increase control valve 62 includes a regulator 52
Regulator pressure P output by_REIs the ratio according to the opening
And output to the rear wheel side hydraulic passage 78. Therefore,
Supplied from the brake ECU 12 to the pressure increase control valve 62
The rear wheel side brake oil pressure P_RIs intensified
It is. Further, the pressure reduction control valve 70 is adapted to the opening degree.
Amount of brake fluid is supplied from the rear wheel side hydraulic passage 78 to the auxiliary reservoir.
It is discharged into the bat tank 66. Therefore, the brake ECU 1
2 according to the drive signal supplied to the pressure reduction control valve 70
And the rear wheel brake pressure P_RIs decompressed. The rear-wheel-side hydraulic passage 78 is arranged in order from the upstream side.
The rear holding valve 82 and the proportioning valve
The valve 84 is provided. The rear wheel side holding valve 82 includes:
The check valves 85 are juxtaposed. The rear wheel side holding valve 82 is
It is a normally open electromagnetic open / close valve.
When the ON signal is given, the valve is closed. Check
The valve 85 is connected to the main hydraulic passage from the wheel cylinder 74, 76 side.
Only the flow toward 58 is allowed. Also, the proportion
Receiving valve 84 is supplied from the rear wheel side hydraulic passage 78.
If the hydraulic pressure is less than the specified value,
While supplying to the wheel cylinders 74 and 76 as they are, the rear wheel side
When the hydraulic pressure supplied from the hydraulic passage 78 exceeds a predetermined value
In order to reduce the oil pressure at a predetermined ratio,
74 and 76. Rear wheel holding valve 8 for rear wheel hydraulic passage 78
2 and the proportioning valve 84,
The rear wheel side pressure reducing passage 86 leading to the reservoir tank 50 communicates.
ing. A rear wheel side pressure reducing valve 88 is provided in the rear wheel side pressure reducing passage 86.
Are arranged. The rear wheel pressure reducing valve 88 is a normally closed electromagnetic
It is an opening / closing valve and receives an ON signal from the brake ECU 12.
By being given, the valve is opened. The rear wheel holding valve of the rear wheel hydraulic passage 78
A front-wheel-side hydraulic passage 90 communicates with the upstream side of 82.
You. A switching valve 92 is provided in the front wheel side hydraulic passage 90.
ing. The switching valve 92 is a normally closed electromagnetic switching valve.
On signal from the brake ECU 12
As a result, the valve is opened. The switching bar of the front-wheel-side hydraulic passage 90
On the downstream side of the lube 92, the oil inside the front wheel side hydraulic passage 90 is
Pressure, ie, front wheel side brake oil pressure P_FDetecting hydraulic pressure
A sensor 91 is provided. Output signal of oil pressure sensor 91
The signal is supplied to the brake ECU 12. Brake E
The CU 12 is driven by the front wheel based on the output signal of the hydraulic pressure sensor 91.
Brake oil pressure P_FIs detected. The front-wheel-side hydraulic passage 90 is connected to the switching valve 92
On the downstream side, the left front wheel wheel 94 to the wheel cylinder 94
Front wheel hydraulic passage 96 and wheel cylinder 98 for the right front wheel
To the right front wheel hydraulic passage 100. Left front wheel oil
In the pressure passage 96 and the right front wheel hydraulic passage 100, respectively,
The left front wheel holding valve 102 and the right front wheel holding valve 104
It is arranged. Left front wheel holding valve 102 and right front wheel holding
The holding valve 104 has check valves 103 and 10 respectively.
5 are juxtaposed. Left front wheel holding valve 102 and right front
The wheel holding valves 104 are both normally open electromagnetic open / close valves.
Yes, an ON signal is given from the brake ECU 12.
As a result, the valve is closed. Also, check valves 103 and 10
5 are front wheels from the wheel cylinders 94 and 98, respectively.
Only the flow toward the side hydraulic passage 90 is allowed. Left front wheel holding valve 1 for left front wheel hydraulic passage 96
02 and the wheel cylinder 94, and the right front wheel
The right front wheel holding valve 104 of the hydraulic passage 100 is
And the front left wheel decompression passage
106 and the right front wheel decompression passage 108 communicate with each other. Front left
Both the wheel decompression passage 106 and the right front wheel decompression passage 108
It communicates with the reservoir tank 50. Left front wheel decompression passage 1
06 and the right front wheel decompression passage 108, respectively,
A pressure reducing valve 110 and a right front wheel pressure reducing valve 112 are provided.
Have been. Left front wheel pressure reduction valve 110 and right front wheel pressure reduction valve
The valve 112 is a normally closed electromagnetic open / close valve.
Open by receiving an ON signal from the ECU 12
It becomes a valve state. The master cylinder 34 has a master pressure passage 1
14 are in communication. The master pressure passage 114 has a master
Cylinder pressure P_{M / C}Master pressure sensor 116 for detecting
Has been established. The output signal of master pressure sensor 116
This is supplied to the ECU 12. Brake ECU 12
Is the master based on the output signal of the master pressure sensor 116.
Cylinder pressure P_{M / C}Is detected. Also, the master pressure passage 11
4 is connected to a stroke simulator 118.
You. In the master pressure passage 114, a wheel of the left front wheel is provided.
Left front wheel master pressure passage 120 leading to cylinder 94;
Right front wheel master pressure passage to right front wheel wheel cylinder 98
122 are in communication. Left front wheel master pressure passage 120 and
The right front wheel master pressure passage 122 has a master serial
Duct cut valves 124 and 126 are provided.
Master cylinder cut valves 124 and 126 are
In addition, a normally open electromagnetic opening / closing valve, the brake ECU 12
The valve is closed by receiving an ON signal from the controller. In this embodiment, an error occurs in the system.
The brake pedal 36 is depressed
At the same time, master cylinder valves 124 and 126
Is closed. In this case, the brake pedal 36
The master cylinder pressure P_{M / C}Rises
Then, the brake fluid in the master cylinder 34 is subjected to the above-described strike.
It flows into the roke simulator 118. Also brake
The depression of the pedal 36 is released, and the master cylinder pressure P
_{M / C}Decreases, the stroke simulator 118
The brake fluid flows into the master cylinder 34. Therefore,
According to the stroke simulator 118, the master syringe
The situation where the Ducat valves 124 and 126 are closed
Under the brake pedal 36, a stroke corresponding to the pedaling force is applied.
Trokes can be generated. It is detected that an abnormality has occurred in the system
In the case, the master cylinder cut valves 124 and 12
6 are both opened. In this case, the wheel on the front wheel side
Cylinders 94 and 98 communicate with master cylinder 34
The hydraulic pressure of the wheel cylinders 94 and 98 is
Pressure P_{M / C}Is guaranteed to be boosted up to
You. The wheel cylinders 74, 76,
If no distinction is made between 94 and 98,
It is simply referred to as “wheel cylinder”. Hydraulic control
In the mechanism 32, the brake pedal 36 is depressed,
In addition, there is no lock
At the time of rake, the rear wheel side holding valve 82 and the rear wheel side pressure reducing valve
88, left front wheel holding valve 102, right front wheel holding valve 1
04, front left wheel pressure reducing valve 110, and front right wheel pressure reducing valve
112 is turned off, and the switching valve 92 and
And master cylinder cut valves 124 and 126 are on
State. Hereinafter, this state is referred to as a normal braking state.
You. In the normal braking state, the rear wheel hydraulic pressure
Passage 78, front wheel side hydraulic passage 90, left front wheel hydraulic passage 96,
The right front wheel hydraulic passage 100 is brought into a conductive state. others
, Rear wheel side brake oil pressure P_RIs proportioning valve
Through the wheel 84 to the wheel cylinders 74 and 76 on the rear wheel side.
And the front wheel brake oil pressure P_FIs the front wheel
To the cylinders 94 and 98. Therefore, the front wheel
Il cylinder pressure P_{W / C}Is the front brake oil pressure P_FMatches
I do. As described above, the rear wheel side brake oil pressure P_RIs a booster system
The pressure is increased according to the opening of the control valve 62, and the pressure reduction control valve
The pressure is reduced according to the opening degree of 70. Therefore, the rear wheel side brake
Key oil pressure P_RAnd front wheel side brake oil pressure P_FBased on
Adjust opening of pressure control valve 62 or pressure reduction control valve 70
The wheel cylinder P_{W / C}To the desired hydraulic pressure
You can control. That any of the wheels has a tendency to lock
When detected, ABS control is started for the wheel.
You. For example, it is detected that the left front wheel FL has a tendency to lock.
Then, ABS control is started for the left front wheel FL.
You. ABS control for the front left wheel FL
In the state, the left front wheel holding valve 102 and the left front wheel pressure reduction
This is realized by opening and closing the valve 110. In the normal braking state, the left front wheel holding
The valve 102 is closed and the left front wheel pressure reducing valve 11 is closed.
When the valve 0 is opened, the wheel cylinder 94
Communicates with the client 50. In this case, the brake fluid
Flows out of the reservoir 94 into the reservoir tank 50,
The oil pressure of the oil cylinder 94 is immediately reduced. This state
This state is hereinafter referred to as a decompression mode. Depending on the pressure reduction mode, the wheel cylinder 94
With the oil pressure reduced, the left front wheel holding valve 102 opens.
And the front left wheel pressure reducing valve 110 is closed.
Then, the wheel cylinder 94 communicates with the main hydraulic passage 78.
For this reason, the oil pressure of the wheel cylinder 94 is
Hydraulic pressure P_RThe pressure is increased toward. Hereinafter, this condition
Called mode. The left front wheel holding valve 102 and the left front wheel
When the pressure reducing valves 110 are both closed, the wheel cylinder
94 is disconnected from the hydraulic actuator 38. others
Therefore, the oil pressure of the wheel cylinder 94 is maintained. This state
Is hereinafter referred to as a holding mode. ABS system for left front wheel FL
The wheel slip rate is kept below a predetermined threshold.
Pressure reduction mode, pressure increase mode, and holding mode
This is executed by switching the mode. Ma
The same applies to the ABS control of the right front wheel FR.
Open / close state of the holding valve 104 and the right front wheel pressure reducing valve 112
Depressurization mode, pressure increase mode, and hold mode depending on the condition
Are formed by switching as appropriate. rear
The wheel side ABS control is performed by the rear wheel side holding valve 82 and the rear wheel side.
By switching the pressure reducing valve 88, the left and right rear wheels
Commonly executed for RL and RR. As described above, the braking force control device of this embodiment
According to this, the regenerative braking force F generated by the drive regenerative device 14
_GAnd the hydraulic braking force F generated by the hydraulic control mechanism 32_LWith
Sum, that is, total braking force F_ALLActing on the vehicle
Can be. Regenerative braking force F_GIs generated, its size
Regenerative energy according to the battery 24
Supplied to Therefore, the state of charge of the battery 24 is maintained.
From the viewpoint of the maximum regenerative braking force F_GmaxIs the required braking force F
_REQUnless it exceeds the maximum regenerative braking force F_Gmaxbe equivalent to
Regenerative braking force F_GAnd the required braking force F_REQTo
Shortfall (F_REQ-F_Gmax) Hydraulic braking force F equal to
_LIs desirable. However, this
The maximum regenerative braking force F_GShall generate
Then, the following inconvenience occurs. That is, as described above, the maximum regenerative braking force F
_GmaxIndicates the state of charge of the battery 24,
It fluctuates according to the degree and the vehicle speed. Therefore, the maximum regeneration system
Power F _GmaxBraking force F equal to_GTo cause
Then, the maximum regenerative braking force F_GmaxIs increased,
Hydraulic braking force F by increase_LIt is necessary to reduce
You. FIG. 23, Regenerative braking force F_G, Hydraulic braking force F_L, And required
Braking force F_REQFIG. For example, FIG.
Period t₁~ T_TwoAs shown in FIG._REQIs constant
And the maximum regenerative braking force F_GmaxWith the increase
Regenerative braking force F_GIs F_G1To F_G2Hydraulic system
Power F_LTo F_L1To F_L2Up to the regenerative braking force F_GIncrease in
The gradient (= (F_G2-F_G1) / (T_Two-T₁A gradient equal to))
It is necessary to reduce by distribution. Hydraulic braking force F_LReduction of the wheel cylinder
Pressure P_{W / C}Depressurizing, that is, the brake
From the wheel cylinder through the pressure reduction control valve 70
By draining it to the auxiliary reservoir tank 66
Is done. In this case, brake full from wheel cylinder
The outflow flow rate of the wheel is the wheel cylinder pressure P_{W / C}And decompression control
The flow is limited by the effect of the orifice of the valve 70 and the like.
Wheel cylinder pressure P_{W / C}Decompression slope
Distribution maximum value (hereinafter, maximum decompression gradient ΔP_maxAlso called)
It will be limited to below the fixed. Therefore, the maximum regenerative braking
Force F_GmaxIs rapidly increased, the maximum decompression gradient ΔP_maxIs regenerating
Braking force F_GOf the total braking force F_ALL
(= Hydraulic braking force F_L+ Regenerative braking force F_G) Is the required braking force F
_REQMay occur. Total braking force F_ALLIs required
Braking force F_REQExceeds the braking force intended by the driver.
Also generates a large braking force,
It gives an unnatural brake feeling. To avoid such inconvenience, the regenerative braking force
F_GThe increasing gradient of the maximum decompression gradient ΔP _maxDepending on
It is necessary to However, the regenerative braking force F_Gof
If the increase gradient is limited, the regeneration supplied to the battery 24
Energy will be reduced. Therefore, the maximum times
In order to secure raw energy, the regenerative braking force F_GIncreasing slope
It is required to keep distribution control to the minimum necessary range.
You. FIG. 4 shows the wheel cylinder pressure P_{W / C}The largest
When the pressure reducing control valve 70 is fully opened to reduce the pressure on the gradient
Wheel cylinder pressure P_{W / C}Thailand showing an example of the time change of
FIG. As shown in FIG. 4, wheel cylinder pressure
P_{W / C}Decreases, the maximum decompression gradient ΔP_maxIs
Decrease. This is, as described later, the wheel cylinder pressure P
_{W / C}Becomes smaller, between the entrance and the exit of the pressure reducing control valve 70.
Differential pressure decreases, and brake fluid from the wheel cylinder
This is because the outflow flow rate of the metal decreases. The braking force control device of the present embodiment is
Maximum decompression gradient ΔP_maxIs the wheel cylinder pressure P_{W / C}To the value of
The wheel cylinder pressure P
_{W / C}From the maximum decompression gradient ΔP at each time_maxAnd estimate
Regenerative braking force F based on the estimated value of_GDetermine the increasing slope of
The total braking force F_ALLIs the required braking force F_REQOn
Ensure maximum regenerative energy while preventing rotation
The feature is that it can be performed. Hereinafter, according to the present embodiment.
The features will be described. First, the maximum pressure reduction gradient ΔP_maxHand to estimate
The method will be described. In this embodiment, the pressure reduction control valve
When the valve 70 is opened, the wheel cylinder
Differential pressure P between Linda and auxiliary reservoir tank 66_diffTo
The brake fluid with the corresponding flow rate Q is the auxiliary reservoir tank
Outflow to 66. And with a gradient according to the outflow diversion Q,
Wheel cylinder pressure P_{W / C}Is decompressed. Auxiliary reservoir
The interior of the tank 66 is maintained at a pressure substantially equal to the atmospheric pressure.
ing. Therefore, the wheel cylinder and the auxiliary reservoir tank
66 and the wheel cylinder pressure P_{W / C}Differential pressure equal to
P_diffCan be regarded as having occurred. Differential pressure P_diff
Is the wheel cylinder pressure P_{W / C}When the flow rate Q is equal to
It is expressed by the following orifice equation. [0045] (Equation 1) However, A is an auxiliary reservoir from the wheel cylinder.
Is the opening area of the path to the
Defined by the orifice area of the pressure reducing control valve 70
You. C is the flow coefficient, γ is the specific gravity of the brake fluid
Quantity, both of which are constants. On the other hand, the wheel cylinder pressure
P_{W / C}And the oil consumption V of the wheel cylinder (that is,
The relationship with the total brake fluid amount V) in the
This is a characteristic peculiar to the wheel cylinder. Fig. 5
Linda pressure P_{W / C}Showing an example of the relationship between the oil consumption V
is there. As shown in FIG. 5, the wheel cylinder pressure P_{W / C}And consumption
Between the oil amount V and the wheel cylinder pressure P_{W / C}Is bigger
The more the gradient of the oil consumption V becomes smaller,
A relationship exists. Here, the decreasing gradient of the oil consumption V is
Equivalent to the flow rate Q of brake fluid flowing out of the cylinder
I do. Therefore, the wheel cylinder P _{W / C}And oil consumption V
The relationship between V = f (P_{W / C})_...(2) The flow rate Q is expressed by the following equation. [0047] (Equation 2) The following equations are derived from the equations (1) and (3). [0049] (Equation 3)By the way, the maximum pressure reduction gradient ΔP_max
Is a wheel cylinder when the pressure reduction control valve 70 is fully opened.
Pressure P_{W / C}Pressure gradient (= -dP_{W / C}/ Dt)
You. Therefore, when the pressure reduction control valve 70 is fully opened,
Opening area A is A₀Then, the maximum decompression gradient ΔP_maxIs next
It is expressed by an equation. [0051] (Equation 4) In the equation (5), C, γ, A₀Is a constant
is there. Also, f (P_{W / C}) Is unique to each wheel cylinder
Since the characteristics are known, P_{W / C}Given d
f (P_{W / C}) / DP_{W / C}Can be obtained. Obedience
Therefore, using equation (5), the wheel cylinder pressure P_{W / C}From
Maximum decompression gradient ΔP_maxCan be estimated. Soshi
And the maximum decompression gradient ΔP_maxDepending on the characteristics of the brake device.
By multiplying the hydraulic braking force F_Lof
Maximum decrease gradient (hereinafter, hydraulic maximum decrease gradient ΔF_maxCalled
Can be estimated. In this embodiment, the brake ECU 12
Is a wheel cylinder based on the output signal of the oil pressure sensor 91.
Da pressure P_{W / C}Is detected. And the hydraulic pressure is
Maximum decreasing gradient ΔF_maxAnd the estimated ΔF_maxTo
The regenerative ECU 10 is notified. The regenerative ECU 10 has a regenerative system.
Power F_GThe increasing gradient of ΔF_maxWithin the range not exceeding
Regenerative braking force F as large as possible_GDrive to generate
The regenerative device 14 is controlled. On the other hand, the brake ECU 12
Is the regenerative braking force F_GRequired braking force F_REQShortfall against
Hydraulic braking force F corresponding to_LTo control the hydraulic pressure
The mechanism 32 is controlled. Therefore, the braking force control device of the present embodiment is
According to the figure, the total braking force F_ALLRequired braking force F _REQEqual to
The maximum regenerative braking force F while controlling_G(Thus,
The maximum regenerative energy) can be secured. Referring to FIGS. 6 and 7, this embodiment will be described.
Executed by the brake ECU 12 and the regenerative ECU 10
The specific processing to be performed will be described. Figure 6 shows a book
Routine executed by brake ECU 12 in the embodiment
6 is a flowchart illustrating an example of the above. Also, FIG.
One of the routines executed by the regenerative ECU 10 in the embodiment.
It is a flowchart which shows an example. 6 and FIG.
The routines shown start synchronously with each other at a predetermined time interval T
This is a routine interrupt routine. When the routine shown in FIG. 6 is started,
First, at step 200, the master cylinder pressure P_{M / C}
Is detected, in step 202, the master serial
Pressure P_{M / C}Braking force F based on_REQIs determined
You. When the processing of step 202 is completed, the next step is
In step 204, the wheel cylinder pressure P_{W / C}Is detected
It is. When the processing of step 204 is completed, the next step
In step 206, the wheel cylinder pressure P_{W / C}From, on
The hydraulic pressure maximum decreasing gradient ΔF_maxEstimate
Calculation processing is performed. Step 206 is completed.
Upon completion, the next step 208 is
Required braking force F determined in 202, 206_{RE Q}And hydraulic
Maximum decreasing gradient ΔF_maxTo the regenerative ECU 10
Sent. The regenerative ECU 10 executes the routine shown in FIG.
In step 300, transmitted from the brake ECU 12
The received signal is received. In step 300,
When the reception of the signal is completed, the processing after step 302 is performed.
Is executed. In step 302, the battery 24
Drive regeneration device 1 based on the state of charge, temperature, vehicle speed, etc.
4 is the maximum regenerative braking force F that can be generated_GmaxIs detected and follows
In step 304, the required braking force F_REQIs the maximum regeneration
Braking force F_GmaxIt is determined whether or not it is larger than. That
As a result, F_REQ> F_GmaxHolds, then step
At 306, the regenerative braking force F_GTarget value F_G0Is up to
Raw braking force F_GmaxAfter being set to a value equal to
08 is executed. On the other hand, in step 304
F_REQ> F_GmaxIf is not established, go to step 310
And the target value F_G0Is the required braking force F_{RE Q}Set to a value equal to
Then, the process of step 308 is performed. In step 308, the control is started in the previous routine.
The generated regenerative braking force F_GThe value of F_G ^{(t -1)}This time against
Target value F_G0Incremental DF_G(= F_G0-F_G ^(t-1)) Is the operation
Is done. In step 310 following step 308, D
F_GIs the oil pressure maximum decreasing gradient ΔF _maxAnd routine execution time
It is determined whether or not it is larger than the product of the interval T. That
Result, DF_G> ΔF_max・ If T holds, target value
F_G0Braking force F equal to_GIs generated, regenerative braking
Force F_GIncrease gradient (= DF_G/ T) is the maximum pressure reduction gradient
ΔF_maxExceeds the required braking force F_REQGreater total system than
Power F_ALLIs determined to be generated. This place
Then, in step 312, the regenerative braking force F_GIncrease
Minute DF_GIs ΔF_max・ After being set to a value equal to T,
The process of step 314 is performed. On the other hand, step 31
0, the DF_G> ΔF_max・ If T is not satisfied,
Standard value F_G0Braking force F equal to_GRegenerates even if
Braking force F_GIs the maximum decrease gradient ΔF_maxOn
It is determined that it will not turn. In this case, step 31
2 is skipped, and then the process of step 314 is performed.
Is executed. In step 314, the regenerative braking force F_Gof
Target value F_G0Is the previous value F_G ^(t-1)And incremental DF_GTo the sum of
Set to equal value. According to the processing of steps 310 to 314,
If the target value F of the regenerative braking force_G0Is the increasing gradient (= DF
_G/ T) is the maximum oil pressure decrease gradient ΔF_maxRange not exceeding
Is set to the maximum size. Step 314
When the process is completed, next in step 316, the regeneration
Braking force F_GTarget value F_G0Signal indicating the brake ECU 1
2 and is followed by a step 318 in which
Standard value F_G0Braking force F equal to_GTo generate
A command signal is supplied to the moving regeneration device 14. Step
When the processing of step 318 is completed, the current routine ends.
Is done. The brake ECU 12 has a routine shown in FIG.
In step 210 in FIG.
Braking force F_GTarget value F_G0Is received. Signal
When the reception is completed, next in step 212, the hydraulic pressure
Braking force F_LTarget value F_L0Is the maximum required braking force F_REQAnd regeneration
Braking force F_GTarget value F_G0Difference (F_REQ-F_GEqual to)
After being set to the target value, in step 214, the target value
F_L0Hydraulic braking force F equal to_LHydraulic control to generate pressure
A command signal is supplied to the mechanism 32. As described above, the regenerative braking force F_GTarget value F_G0
Is the arithmetic expression F_G0= F_G ^(t-1)+ DF_GIs set by
You. Therefore, by the calculation processing of step 212, F
_L0Is (F_REQ-F_G ^(t-1)) -DF_GHas a value equal to
You. By the way, the execution of the routine shown in FIGS.
The time interval T is equal to the assumed required braking force F._REQLap of change
Is set short enough for the
Power F_REQHas changed since the previous execution of the routine.
Can be regarded as not. Therefore, (F_REQ-F_G
^(t-1)) Is the hydraulic pressure generated during the previous routine
Braking force F_LIs equal to Also, as described above, DF
_GIs the oil pressure decrease gradient ΔF_maxAnd routine execution time interval
Product ΔF with T_max・ It is set not to exceed T
You. Therefore, in step 214, the hydraulic pressure
Large decrease gradient ΔF_maxTarget value F without being limited to_L0
Hydraulic braking force F equal to_LIs guaranteed to be able to generate
You. Therefore, according to the routine shown in FIGS.
The required braking force F_REQBraking force F equal to_ALLTo
Can be generated. As described above, in the present embodiment, the e
Il cylinder pressure P_{W / C}Based on the hydraulic pressure maximum decreasing gradient ΔF
_maxIs estimated, and the regenerative braking force F_GIs increasing
Fixed ΔF_maxIs set to the maximum without exceeding
You. Therefore, according to the braking force control device of the present embodiment,
Braking force F_REQBraking force F equal to_ALLWhile generating
The regenerative energy can be maximized. In the above embodiment, the routine
The required braking force F during the execution time interval T _REQIs constant
I decided to consider it. However, the required braking force F_REQof
In consideration of the change, the past required braking force F_REQUsing the value of
Required braking force F_REQOf the regenerative braking force F_Gof
Increasing gradient and required braking force F_REQOil is the largest sum with increasing slope
Pressure decrease gradient ΔF_maxRegenerative braking force F so as not to exceed_GTo
It may be determined. In the above embodiment, the hydraulic controller
The structure 32 is provided with a drive regenerative device
The device 14 is connected to the regenerative braking means described in the claims,
Is equivalent. The brake ECU 12 is shown in FIG.
The routine is executed and the regenerative ECU 12 operates as shown in FIG.
Executing a routine to execute the cooperative control described in the claims.
The control means controls the brake ECU 12 to execute the routine shown in FIG.
Executing the process of step 206 to enter the claims
The mounted oil pressure maximum decreasing gradient estimating means is provided by the regenerative ECU 10.
Processing of steps 310 and 312 of the routine shown in FIG.
By executing the regenerative increase gradient determination described in the claim.
Setting means are respectively realized. [0064] As described above, according to the present invention, the hydraulic braking
To prevent the sum of force and regenerative braking force from exceeding the required braking force.
While ensuring maximum regenerative energy
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram of a braking force control device according to an embodiment of the present invention. FIG. 2 is a system configuration diagram of a hydraulic control mechanism of the present embodiment. [Figure 3] required braking force F _REQ, it is a diagram showing an example of time change of the regenerative braking force F _G, and hydraulic braking force F _L. 4 is a diagram showing an example of time change of the wheel cylinder pressure P _{W / C} in the case of the wheel cylinder pressure P _{W / C} under reduced pressure at a maximum pressure gradient. FIG. 5 is a diagram showing an example of a relationship between a wheel cylinder pressure P _{W / C} and a consumption flow rate V of the wheel cylinder. FIG. 6 is a flowchart of an example of a routine executed by a brake ECU in the embodiment. FIG. 7 is a flowchart of an example of a routine executed by a regenerative ECU in the embodiment. [Description of Signs] 10 Regenerative ECU 12 Brake ECU 14 Drive regeneration device 32 Hydraulic pressure generating mechanism

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 8/00-8/96 B60L ⁷ /22-7/24 B60T 13/66-13/74

Claims (1)

(57) [Claim 1] A hydraulic braking means for generating a hydraulic braking force,
In a braking force control device comprising: a regenerative braking unit that generates a regenerative braking force; and a cooperative control unit that performs a cooperative operation of the hydraulic braking unit and the regenerative braking unit. Hydraulic pressure maximum decreasing gradient estimating means, and regenerative increasing gradient determining means for determining an upper limit value of the increasing gradient of the regenerative braking force based on the maximum decreasing gradient estimated by the hydraulic maximum decreasing gradient estimating means. A braking force control device, characterized in that: