JP4400453B2 - Brake control device for vehicle - Google Patents

Description

The present invention relates to a braking system GoSo location of the vehicle to change the braking distribution under prescribed conditions between the front and rear wheels (replacement).

For example, Patent Document 1 describes a vehicle braking control device that performs cooperative braking control using two types of braking means in combination.
In this braking control device, a hydraulic braking means or the like and a regenerative braking means using an electric load by a motor / generator are used in combination, and the sum of the friction braking force and the regenerative braking force is a required total braking force. This is a regenerative cooperative brake control device that controls to match the above. Under the predetermined condition, the braking force is changed between the friction braking force and the regenerative braking force while maintaining the required total braking force to be the same, and the braking distribution of the front and rear wheels is changed.
Japanese Patent Laid-Open No. 11-098609

If the frictional braking force and regenerative braking force are changed between the front and rear wheels for the ideal front / rear distribution state and the braking distribution between the front and rear wheels is simply changed, the front / rear distribution will only collapse if the vehicle is running straight ahead. However, a new yaw moment is generated when the vehicle is turning. That is, during turning, a new yaw moment unintended by the driver is generated due to the circumstances of the vehicle. For example, when the steered wheel is a front wheel, if the braking force is simply changed from the rear wheel to the front wheel, a yaw moment in the understeer direction is newly generated during turning. On the other hand, when the braking force is changed from the front wheel, which is the steered wheel, to the rear wheel, a yaw moment in the oversteer direction is newly generated. Even if the braking force distribution of the left and right steered wheels is kept constant and the braking force is always distributed so as to be ideally distributed, the yaw moment changes if the required total braking force changes during a turn.
The present invention has been made paying attention to the above points, and provides a vehicle braking control device capable of suppressing the influence on the vehicle behavior even when the braking force is changed between the wheels. Is an issue.

  In order to solve the above problem, the present invention distributes the braking force distribution of the left and right wheels on at least one of the front wheel and the rear wheel so as to suppress a change in vehicle behavior caused by a change in the braking force distribution of the front and rear wheels. To be adjusted.

  According to the present invention, when the braking force distribution of the front and rear wheels is changed, the braking force distribution between the left and right wheels is adjusted in a direction to suppress the vehicle behavior change, for example, the braking force is distributed during turning. Even if there is a change, it is possible to suppress or reduce the occurrence of the vehicle behavior that is not intended by the driver and that accompanies the distribution change.

Next, embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the present embodiment. While the regenerative braking force is controlled by the AC synchronous motor 13, the regenerative energy is efficiently recovered by controlling the brake fluid pressure to be reduced. It is the example which applied this invention with respect to the braking control apparatus provided with the "control system."
As shown in FIG. 1, friction braking means for applying braking by friction braking force to a wheel based on fluid pressure, and regenerative braking means for applying braking by regenerative braking force using an electric load by a motor 13. Works. Here, in the present embodiment, the front wheels are steering wheels, the front wheel braking means is only friction braking means, the rear wheels are non-steering wheels, and the rear wheel braking means are friction braking means and regenerative braking means. A configuration example is as follows. Note that the rear wheels that are non-steering wheels are other wheels, but the other wheels are not necessarily non-steering wheels.

  In FIG. 1, reference numeral 1 denotes a brake pedal 1 that is operated to instruct a braking force requested by a driver, and the brake pedal 1 is connected to a master cylinder 3 through a hydraulic booster 2. The hydraulic booster 2 boosts the braking pressure (pedal pedaling force) according to the depression amount of the brake pedal 1 using the high braking fluid pressure increased by the pump 20 and accumulated in the accumulator 21 to the master cylinder 3. Supply. The high control fluid pressure is also used as a source pressure for fluid pressure feedback control. The pump 20 is sequence-controlled by a pressure switch 22. Reference numeral 23 denotes a reservoir of control fluid.

The master cylinder 3 is connected to a wheel cylinder 17 of each wheel via a fluid path switching electromagnetic valve 4. FIG. 1 shows a state in which the fluid path switching electromagnetic valve 4 is not energized, and shows a state in which the fluid in the master cylinder 3 is supplied to the wheel cylinder 17 as it is.
When the fluid path switching electromagnetic valve 4 is energized, the master cylinder 3 is connected to the stroke simulator 5 (an oil load equivalent to that of the wheel cylinder 17) and is cut off from each wheel cylinder 17. In this state, when a proportional solenoid valve for fluid pressure control for pressure increase (hereinafter referred to as the pressure increasing solenoid valve 6) is energized, the output pressure of the pump 20 or the accumulated pressure of the accumulator 21 is supplied to each wheel cylinder 17. If the proportional pressure solenoid valve for pressure control of fluid pressure (hereinafter referred to as the pressure reducing solenoid valve 7) is energized, the braking fluid pressure of each wheel cylinder 17 is reduced to the reservoir 23. And depressurize. As a result, the brake fluid pressure of each wheel cylinder 17 can be individually controlled.

The output pressure of the master cylinder 3 (the driver's required braking amount) is detected by the pressure sensor 8, and the detection signal is supplied to the fluid pressure braking controller 10. Further, the braking fluid pressure of each wheel cylinder 17 in a state of being disconnected from the master cylinder 3 is detected by the pressure sensor 9, and the detection signal is also supplied to the fluid pressure braking controller 10.
The fluid pressure braking controller 10 is for increasing pressure based on the detection signals from the pressure sensors 8 and 9 in a state where the master cylinder 3 and the wheel cylinders 17 are separated by the fluid path switching electromagnetic valve 4. By controlling the electromagnetic valve 6 and the pressure reducing electromagnetic valve 7, the control fluid pressure of each wheel cylinder 17 is individually controlled, thereby applying a braking force by a friction load of a desired magnitude to the wheel.

  On the other hand, the AC synchronous motor 13 is connected to the drive wheel (rear wheel in the present embodiment) via the speed reduction mechanism 24 in addition to the engine (not shown). The motor 13 functions as a drive motor 13 that transmits driving force to the drive wheels, and also functions as a generator by road surface driving torque from the drive wheels, and converts the vehicle kinetic energy by regenerative braking control into a DC / AC conversion current control circuit. The battery 25 is charged via (inverter 14). That is, when the electric power is recovered to the battery 25, the road surface driving torque is consumed for rotating the motor 13, and as a result, a braking force is applied to the driving wheels. The inverter 14 converts an alternating current and a direct current based on the three-phase PWM signal from the motor controller 11. That is, the motor 13 is controlled based on a command from the motor controller 11.

The motor controller 11 controls the regenerative braking force based on the regenerative braking force command value from the regenerative cooperative braking controller 12. Further, the driving force is controlled by the motor 13 during driving. In addition, the motor controller 11 calculates a maximum allowable regenerative force value determined by the state of charge of the battery 25, the temperature, and the like, and supplies the calculation result to the regenerative cooperative controller 12. Here, the code | symbol 15 is a wheel speed sensor for measuring wheel speed, for example, a magnetic pick-up etc. are used. Reference numeral 16 denotes a steering angle sensor using an encoder or the like.
Here, the fluid pressure braking controller 10, the motor controller 11, and the regenerative coordination controller 12 are, for example, a CPU, a ROM, a RAM, a digital port, an A / D port, a one-chip microcomputer having various timer functions (or the same function). A plurality of chips) and a high-speed communication circuit.

Although only one wheel is shown in FIG. 1, the fluid pressure braking system is configured similarly for the other three wheels so that braking to each wheel can be individually controlled. In the present embodiment, the regenerative braking system by the motor 13 is configured such that only the rear wheels are independent of the left and right wheels. In the present embodiment, the left and right front wheels are steering wheels, and the left and right rear wheels are non-steering wheels.
FIG. 2 shows a functional configuration diagram related to the present invention. In this functional configuration diagram, the independent braking means is configured by the fluid pressure braking controller 10 and the motor controller 11, and other functions are configured by the regenerative coordination controller 12.

Next, the process of the regeneration cooperative controller 12 will be described with reference to FIG. In the present embodiment, acceleration and torque are defined as negative values of deceleration and torque in the braking direction.
The processing of the regenerative cooperative controller 12 is performed every predetermined sampling period (for example, 10 msec). First, in step S10, based on the detection signals from the pressure sensors 8 and 9, the output pressure Pmc (driver) of the master cylinder 3 ) And the brake fluid pressure Pwc of each wheel cylinder 17 are calculated, and the process proceeds to step S20.

In step S20, each wheel speed is measured using a timer with an input capture function built in the microcomputer based on a signal from the wheel speed sensor, and the maximum value is set to Vw. Further, bandpass filter processing indicated by a transfer function Fbpf (s) of the following equation (1) is performed to obtain a driving wheel deceleration estimated value αv, and the process proceeds to step S30. Actually, it is calculated using a recurrence formula obtained by discretization by Tustin approximation or the like. Here, s is a Laplace operator, ω is a natural angular frequency, and ζ is an attenuation constant.
Fbpf (s) = s / {(s ² / ω ² ) + (2ζs / ω) +1} (1)

In step S30, the currently allowable maximum allowable regenerative torque Tmmax is read from the high-speed communication reception buffer with the motor controller 11, and the process proceeds to step S40. The maximum allowable regenerative torque Tmmax is determined by the motor controller 11 according to the battery charging rate and the like.
In step S40, the target deceleration rate αdem is calculated using the master cylinder pressure Pmc and the vehicle specification constant K1 previously stored in the ROM, and the process proceeds to step S50.
αdem = − (Pmc × constant K1) (2)
Here, the target deceleration rate αdem is determined not only by the physical quantity commanded by the driver by the master cylinder fluid pressure Pmc, but also in the case of a vehicle configured to perform control such as inter-vehicle distance control and vehicle speed control. The setting is also changed according to the physical quantity by automatic control braking.

In step S50, a braking torque command value Td-FF (feed forward term) necessary for realizing the target deceleration rate αdem is calculated, and the process proceeds to step S60. Specifically, the target deceleration rate αdem is first converted into a braking force using the vehicle specification constant K2. Further, in order to make the response characteristic Pm (s) of the vehicle to be controlled coincide with the reference model characteristic Fref (s), CFF (s) represented by the following equation (3) of the feedforward compensator (phase compensator). Is applied to calculate the braking torque command value Td-FF (feed forward term). Actually, the calculation is performed by discretization as described above.
CFF (s) = Fref (s) / Pm (s)
= (Tp · s + 1) / (Tr · s + 1) (3)

In step S60, the master cylinder pressure Pmc is compared with a predetermined value (a value close to zero). If the master cylinder pressure Pmc is larger (the driver has a braking operation), the process proceeds to step S70. None) Proceed to step S90.
In step S70, a braking torque command value Td-FB (feedback term) necessary for realizing the target deceleration rate αdem is calculated by the following process, and the process proceeds to step S80. Here, the deceleration controller of the present embodiment is composed of a “two-degree-of-freedom control system” as shown in FIG. 4, and includes a feedforward compensator (block A), a reference model (block B), and feedback compensation. (Block C). Closed-loop performance such as stability and disturbance resistance is adjusted by a feedback compensator, and responsiveness to a target acceleration is basically adjusted by a feedforward compensator (in the absence of a modeling error).

First, a reference deceleration rate αref is calculated by applying a reference model Fref (s) represented by the following equation to the target deceleration rate αdem.
Fref (s) = 1 / (Tr · s + 1) (4)
A feedback deviation Δα is calculated by subtracting the estimated deceleration value αv described above from the reference deceleration rate αref thus calculated.
Δα = αref−αv (5)

Then, a feedback compensator CFB (s) is applied to the feedback deviation Δα to calculate a braking torque command value Td-FB (feedback term). In this embodiment, the feedback compensator CFB (s) is realized by a basic PI controller as shown in the following equation (6). The control constants Kp and Ki in the following equation are set in consideration of gain margin and phase margin.
CFB (s) = (Kp.s + Ki) / s (6)

In step S80, the braking torque command value Td-com is calculated by adding the F / F term and the F / B term of the obtained braking torque command value with an adder, and the process proceeds to step S100. The above equations (4) and (6) are calculated by a recurrence equation obtained by discretization as described above.
On the other hand, in step S90, the braking torque command value Td-FB (feedback term) and all internal variables used for feedback compensator calculation (digital filter) are initialized (the integral term of the PI compensator is initialized).

In S100, the braking torque command value Td-com is ideally distributed to the front and rear wheels, and the process proceeds to Step S110. That is, an ideal distribution line that simultaneously locks the front and rear wheels in consideration of the front and rear load movement at the time of deceleration, or a distribution line that is slightly biased toward the front wheels and avoided that the rear wheels are locked first is shown in FIG. The basic front / rear distribution characteristics as shown in FIG. 5 are tabulated in advance, and the front wheel braking torque command values Td-FR, Td-FL and the rear wheel This is distributed to the braking torque command values Td-RR and Td-RL. That is, the basic distribution amount for each of the four wheels is determined.
Td-FR = 0.5 x front wheel front lookup (input: Td-com)
Td-FL = 0.5 x front wheel front lookup (input: Td-com)
Td-RR = 0.5 x front wheel reference (input: Td-com)
Td-RL = 0.5 x Rear wheel front lookup (input: Td-com)

In step S110, within the range of the braking torque command value of each wheel ideally distributed in the front-rear direction obtained in step S100, for the purpose of improving fuel efficiency, the rear wheel side is set to the regenerative braking torque command value as much as possible, and the rest is subjected to fluid pressure braking It distributes to a torque command value, and proceeds to step S120. The basic distribution of the four wheels will not change. However, the present embodiment is a configuration example in which only the rear wheels have the regenerative braking means as described above, and all the braking torques are negative values.
That is, in step S110, the braking torque command values for the left and right rear wheels set in step S100 are allocated to the regenerative braking torque command value and the fluid pressure torque command value, respectively, and the process proceeds to step S120. At the time of the distribution, processing is performed so as to distribute to the regenerative braking torque command value as much as possible.

That is, first, the distribution amount to the regenerative braking torque command value is obtained based on the following equation. If the braking torque command value is smaller than the maximum allowable regenerative amount that can be used, the regenerative braking torque command value becomes a command value equal to the maximum allowable regenerative amount. Otherwise, the regenerative braking torque command value becomes the same value as the braking torque command value, and the fluid pressure braking torque command value becomes zero.
Tm0-RR = max (Td-RR, Tmmax-RR)
Tm0-RL = max (Td-RL, Tmmax-RL)
Here, Tmmax-RR and Tmmax-RL are maximum allowable regenerative torques on the left and right rear wheels, respectively.

Subsequently, a fluid pressure braking torque command value for each wheel is obtained based on the following equation. On the front wheel side, the braking torque command value becomes the fluid pressure braking torque command value as it is, but on the rear wheel side, only the amount not allocated to the regenerative braking torque command value becomes the fluid pressure braking torque command value.
Tb0-FR = Td-FR
Tb0-FL = Td-FL
Tb0-RR = Td-RR-Tm0-RR
Tb0-RL = Td-RL-Tm0-RL

In step S120, after operating the excess distribution calculating part which comprises a distribution change means, and performing the correction | amendment based on steering angle information, it transfers to step S130.
In step S130, based on the fluid pressure braking torque command value for each wheel, the vehicle pressure constant K3 stored in the ROM in advance is used to calculate the fluid pressure command value for each front and rear wheel as shown in the following equation, and the process proceeds to step S140. Transition.
Pb-FR =-(Tb-FR x constant K3)
Pb-FL =-(Tb-FL × constant K3)
Pb-RR =-(Tb-RR × constant K3)
Pb-RL =-(Tb-RL × constant K3)
In step S140, the fluid pressure command value and the regenerative braking torque command value for each wheel are supplied to the fluid pressure braking controller 10 and the motor controller 11, respectively, and the process ends.

Next, the process of the excess allocation calculating unit will be described with reference to FIG.
First, in step S300, a regenerative braking torque margin for regenerative rear wheels is calculated based on the following formula, and the process proceeds to step S310.
Tmmargin-RR = Tmmax-RR-Tm0-RR
Tmmargin-RL = Tmmax-RL-Tm0-RL
In step S310, a braking torque ΔT that can be changed between the front and rear wheels is calculated based on the following formula, and the process proceeds to step S320. However, all braking torques are negative values.
ΔT = max {(Tmmargin-RR + Tmmargin-RL), (Tb0-FR + Tb0-FL)}

  That is, the smaller absolute value of the total regenerative braking torque margin and the front wheel side total braking torque command value is set as the braking torque ΔT that can be exchanged between the front and rear wheels. Thus, as will be described later, if the absolute value of the total braking torque command value on the front wheel side is smaller, the total braking torque command value on the front wheel side is replaced with the regenerative braking side on the rear wheel side. On the other hand, if the absolute value of the total braking torque command value on the front wheel side is larger, only the margin of the total regenerative braking torque is replaced on the regenerative braking side.

In step S320, the steering angle δ, which is steering information, is obtained from the detected value obtained by measuring the rotation angle and direction based on the edge or level of the output pulse of the steering angle sensor such as an encoder in another process with a shorter calculation cycle. The process proceeds to step S330.
In step S330, the actual steering angle β of the front wheels is calculated from the steering angle δ using the steering gear ratio. Further, in step S340, LFL, LFR, LRL, and LRR (moment arm length) from the vehicle center of gravity to the rotation direction vector of each wheel are calculated based on the following formula, and the process proceeds to step S350. The orthogonal distances LA, LB, LF, LR are defined as shown in FIG.
LFL = (LF ² + LA ² ) ^1/2 × sin (φ−β)
However, LA / LF = tanφ
LFR = (LA + LB) × cos β−LFL
LRL = LA
LRR = LB

In step S350, braking force replacement amounts FFR, FFL, FRR, FRL of the respective wheels satisfying the following expressions (10) and (11) are calculated, and the process proceeds to step S360. R is an effective tire radius. For example, assuming that FRL = FRR, it is easy to solve because it is a simultaneous linear equation of FFR and FFL. Further, the regenerative braking means for the rear wheels is not necessarily left and right independent.
A) Conditions for constant total braking force FFR + FFL = FRR + FRL = ΔT / R (10)
B) Conditions without new yaw moment generation FFL x LFL-FFR x LFR-FRL x LRL + FRR x LRR = 0 (11)

In step S360, the final regenerative braking torque command value and fluid pressure braking torque command value for each wheel are calculated based on the following formula, and then the process returns.
(Regenerative braking torque command value)
Tm-RR = Tm0-RR + FRR × R
Tm-RL = Tm0-RL + FRL × R
Fluid pressure braking torque command value)
Tb-FR = Tb0-FR -FFR x R
Tb-FL = Tb0-FL -FFL x R
Note that the fluid pressure braking torque command value on the rear wheel side is not changed.
Here, the step S320 constitutes a steering detection means and a behavior change determination means, and the steps S330 to s360 constitute a left and right wheel distribution adjustment means.

Next, the operation, action, and effect of the above control will be described.
Here, the device configuration of the vehicle in the present embodiment may be, for example, the configuration shown in FIG. In this configuration example, friction braking force can be applied to all four wheels independently, and regenerative braking force can be applied independently to the left and right for regenerative braking of the rear wheels.
In the present braking control device, when the brake pedal 1 is depressed, a total braking torque command value Td-com corresponding to the request is obtained, and the total braking torque command value Td-com is assigned to a predetermined ideal distribution ( For example, as described above, the front and rear wheels are distributed to the front and rear wheels on the basis of a distribution that is simultaneously locked. At this time, on the rear wheel side where braking is performed by both friction braking and regenerative braking, each braking torque command value allocated to the left and right rear wheels is individually allocated to friction braking and regenerative braking. In this case, the fuel consumption can be improved by distributing to the regenerative braking side as much as possible.

Furthermore, when there is a margin in the regenerative braking force, priority is given to improving fuel efficiency, and part or all of the braking torque command value on the front wheel side that is the steered wheel is regenerated on the rear wheel side that is the non-steered wheel. Replace with. In the state where there is a margin in the regenerative braking force, braking on the rear wheel side is performed only by regenerative braking, and the fluid pressure braking torque command value on the rear wheel side is in a zero state.
By performing such control, for example, assuming that the maximum regenerative braking force is constant, when the brake pedal 1 is gradually depressed and the required total braking force gradually increases, the regenerative braking force is first applied to the rear wheels. Arise. Furthermore, if the required total braking force exceeds the maximum regenerative braking force, friction braking force is also applied to the front wheels, and when the front and rear braking force balance reaches the ideal state, the front and rear wheel friction control is maintained while maintaining the ideal distribution state. The power increases according to the required total braking force.

  On the other hand, if the maximum regenerative braking force gradually increases while the required total braking force is constant, the front and rear ideal distribution is maintained until the rear wheel friction braking force is completely replaced by the regenerative braking force. When the regenerative braking force increases, the friction braking force on the front wheel side is replaced with the regenerative braking force on the rear wheel, and the front-rear ideal distribution changes. Note that the maximum regenerative braking force varies depending on the charging rate of the battery 25 that receives regenerative power, the rotational speed of the motor 13 (proportional to the vehicle speed), and the like.

  Here, regardless of whether the total braking force is in the front-rear ideal distribution state, the braking force is simply changed between the front and rear wheels, that is, the friction braking force of the front wheels is changed to the regenerative braking force of the rear wheels, and Assuming that the left and right wheels are simply replaced by the same amount, the front-rear distribution will only be disrupted if the vehicle is running straight, but priority should be given to improving fuel consumption when turning. As a result, a new yaw moment unintended by the driver is generated.

  On the other hand, in the braking control device of the present embodiment, the allocation amount of the replacement of the front wheels on the left and right wheels is optimized based on the steering information so as to satisfy the expressions (10) and (11). By doing so, it is possible to suppress generation of a new yaw moment due to replacement while realizing the required total braking torque. As a result, it is possible to prevent deterioration in steering stability while performing regenerative braking to the maximum even during turning.

  FIG. 9 shows an example of changing the braking force between the front and rear wheels by the above control. If the vehicle turns left as shown in FIG. 9A, the moment arm on the left front wheel side becomes shorter and the moment arm on the right front wheel side becomes longer. When changing from the front wheel side, which is the steered wheel, to the rear wheel side according to the ratio of the length, as shown in FIG. 9B, the left side replacement amount is made larger than the right front wheel side replacement amount. By performing the distribution adjustment, the generation of a new yaw moment accompanying the replacement is reduced or zero.

Here, although the case where the steering wheel is the front wheel is illustrated in the above embodiment, the rear wheel may be the steering wheel.
Moreover, the vehicle which performs regenerative braking on the steered wheel side may be used.
In the above embodiment, a braking system that uses both regenerative braking and friction braking as braking means has been described. However, a braking system that uses only one braking means may be used. In short, any system that automatically changes or replaces the distribution between the left and right steered wheels and another vehicle under any condition may be used.
The other wheels may also be steering wheels that make a pair on the left and right. In this case, distribution adjustment may be performed on the other wheels based on the steering information between the left and right wheels.

Next, a second embodiment will be described with reference to the drawings. Components and processes similar to those in the first embodiment will be described with the same reference numerals.
The basic configuration of this embodiment is the same as that of the first embodiment, but the processing of the excess allocation calculation unit is different.
Next, the process of the excess allocation calculating unit of the second embodiment will be described with reference to FIG.
First, in step S500, the steering angle δ, which is steering information, is obtained from the detected value obtained by measuring the rotation angle and direction based on the edge or level of the output pulse of the steering angle sensor such as an encoder in another process with a shorter calculation cycle. The process proceeds to step S510.

In step S510, the actual steering angle β of the front wheels is calculated from the steering angle δ using the steering gear ratio. Subsequently, in step S520, the orthogonal distances LFL, LFR, LRL, and LRR (moment arm lengths) from the vehicle center of gravity to the rotational direction vector of each wheel are calculated based on the following formula, and the process proceeds to step S530. . LA, LB, LF, and LR are defined as shown in FIG.
LFL = (LF ² + LA ² ) ^1/2 × sin (φ−β)
However, LA / LF = tanφ
LFR = (LA + LB) × cos β−LFL
LRL = LA
LRR = LB

In step S530, giving priority to not generating a new yaw moment, the replacement amount of front and rear wheels (FFR + FFL) while satisfying the following three conditions (13), (14), and (15): The amount of replacement of each wheel braking force is calculated so as to maximize the value, and the process proceeds to step S540. For example, it may be simplified assuming that FRL = FRR. R is an effective tire radius.
(A) Conditions for constant total braking force FFR + FFL = FRR + FRL (13)
(B) Conditions without new yaw moment generation FFL x LFL-FFR x LFR-FRL x LRL + FRR x LRR = 0 (14)

(C) Various restrictions on the amount of braking force replacement for each wheel (15)
(Restricted by lock limit value and maximum regenerative braking amount of each wheel)
0 ≧ Tb-FR = Tb0-FR −FFR × R ≧ FLMT-FR × R
0 ≧ Tb-FL = Tb0-FL −FFL × R ≧ FLMT-FL × R
0 ≧ Tm-RR = Tm0-RR + FRR × R ≧ max (FLMT-RR × R, Tmmax-RR)
0 ≧ Tm-RL = Tm0-RL + FRL × R ≧ max (FLMT-RL × R, Tmmax-RL)
here,
FLMT-FR: Lock limit value for right front wheel FLMT-FL: Lock limit value for left front wheel

Here, in a vehicle configuration in which the rear wheels have regenerative braking torque control means that are independent of the left and right, when the left and right difference is given only by the braking force of the front wheels, the rear wheel braking force replacement amounts FRR and FRL are equal to the left and right. Therefore, assuming that the amount of braking torque change before and after is ΔT, the rear wheel braking force replacement amounts FRR and FRL are expressed by the following equations from Equation (13).
FRR = FRL = ΔT / 2 (16)

Based on the conditions of the equations (13) and (14) and (15), the braking force replacement amounts FFR and FFL of the front wheels are obtained as follows.
FFR = ΔT × (2LFL−LRL + LRR) / (2R × (LFL + LFR))
(17)
FFL = ΔT × (2LFR + LRL−LRR) / (2R × (LFL + LFR))
(18)

At this time, since the front-rear change amount ΔT is not determined, the front-rear change amount ΔT that maximizes the regenerative amount is obtained by the following method using the constraint condition (15).
Here, in this embodiment, in the front / rear ideal distribution before the front / rear replacement is performed, it is assumed that the front / rear braking force has not reached the lock limit. Based on this premise, the braking amount is changed from the front wheel to the rear wheel, so the braking force decreases at the front wheel and increases at the rear wheel after changing the braking amount with respect to the ideal distribution. Can be simplified as follows.

Simplified constraints
0 ≧ Tb0-FR−FFR × R (19.1)
0 ≧ Tb0-FL−FFL × R (19.2)
Tm0-RR + FRR x R ≥ max (FLMT-RR x R, Tmmax-RR)
(19.3)
Tm0-RL + FRL x R ≥ max (FLMT-RL x R, Tmmax-RL)
(19.4)

Then, the limit values ΔTlilm-1 and ΔTlim-2 of the front and rear replacement amount in the conditional expressions (19.1) and (19.2) for the front wheels are changed into the above expressions (17) and (19) in the conditional expressions (19.1) and (19.2), respectively. It calculates from the following formula which substituted (18).
ΔTlim-1 = (2 × Tb0−FR × (LFL + LFR)) / (2 × LFL−LRL + LRR)
ΔTlim-2 = (2 × Tb0-FL × (LFL + LFR)) / (2 × LFR + LRL−LRR)

Further, the limit values ΔTlim-3 and ΔTlim-4 of the front and rear replacement amount in the conditional expressions (19.3) and (19.4) for the front wheels are changed into the conditional expressions (19.3) and (19.4), It is calculated from the following formula substituted and transformed.
ΔTlim-3 = 2 (max (FLMT-RR × R, Tmmax-RR) −Tm0-RR
ΔTlim-4 = 2 (max (FLMT-RL × R, Tmmax-RL) −Tm0-RL
At this time, since the regenerative braking torque control means for the rear wheels is independent of left and right, the left and right values of the maximum regenerative braking amount and the basic distributed regenerative braking torque command value are equal as shown in the following equation.
Tmmax-RR = Tmmax-RL
Tm0-RR = Tm0-RL

The maximum value ΔT of the replacement amount that never generates the yaw moment is calculated from the limit value of the front / rear replacement amount obtained from the condition of each wheel by the following formula.
ΔT = max (ΔTlim-1, ΔTlim-2, ΔTlim-3, ΔTlim-4)
The replacement amount maximum value ΔT calculated in this way is substituted into the equations (16) to (18) to calculate the replacement amount before and after.

In step S540, the final regenerative braking torque command value and the fluid pressure braking torque command value for each wheel are calculated based on the replacement amount, and the process ends and returns.
(Regenerative braking torque command value)
Tm-RR = Tm0-RR + FRR × R
Tm-RL = Tm0-RL + FRL × R
Fluid pressure braking torque command value)
Tb-FR = Tb0-FR-FFR x R
Tb-FL = Tb0-FL-FFL x R
Tb-RR = 0
Tb-RL = 0
Other configurations are the same as those of the first embodiment.

Next, operations and effects of the second embodiment will be described.
Regenerative braking force allowance of each wheel (the amount left over with respect to the maximum regenerative braking amount), distributed friction braking torque, or braking force that can be transmitted to the road surface in the state of ideal distribution before and after braking force (Lock limit) is finite, and if the replacement amount of the front and rear wheels is preferentially determined first, the generation of a new yaw moment may not be avoided only by the distribution of the left and right wheels of the replacement amount.

In this embodiment, the braking force (lock limit) that can be transmitted to the road surface is taken into consideration, and priority is given to avoiding the generation of the yaw moment, and the amount of replacement of the front and rear wheels is limited, so that the steering stability can be further maintained. There is.
Other operations and effects are the same as those in the first embodiment.
Here, in all the above embodiments, when the front and rear braking forces are changed, control is performed such that the distribution of the braking forces to the left and right steering wheels is different by an amount corresponding to the steering amount. It is not limited to.

For example, when changing the front / rear braking force, the distribution to the left and right steering wheels may be adjusted so that a certain difference in braking force is applied according to the direction of steering. Of the steered wheels, it is determined which of the steered wheels the distribution is to be increased, and the magnitude of the braking force difference to be distributed to the left and right steered wheels is determined based on other information such as the lateral G. Also good.
Here, in the first and second embodiments, a new yaw moment, which is a change in vehicle behavior due to a front-rear change, is generated by adding a left-right braking force difference on the front wheel side that is a steered wheel that does not perform regenerative braking. Although it suppresses, it is not limited to this.

In short, it is only necessary to adjust the braking force difference between the left and right wheels in at least one of the front wheels and the rear wheels so as to satisfy the expressions (13) and (14) and the constraint condition (15). The adjustment of the left and right braking force is not limited to fluid pressure braking, that is, friction braking, but may be performed by regenerative braking, or may be performed using both brakings. Further, a vehicle configuration in which regenerative braking is performed on the front wheel side may be employed. In the following third to fifth embodiments, an example of processing in that case will be described.
In addition, when performing front-and-rear replacement for regenerative braking priority, regenerative braking is used only on one of the front wheels or the rear wheels. However, when the front / rear change process is performed for a reason different from the regenerative braking priority, the regenerative braking may be performed on both the front wheels and the rear wheels.

Next, a third embodiment will be described with reference to the drawings. In addition, about the components similar to said each embodiment, the same code | symbol is attached | subjected and demonstrated.
The basic configuration of this embodiment is the same as that of each of the above embodiments. However, by adjusting the braking force difference between the left and right rear wheels, the generation of a new yaw moment associated with replacement is suppressed or eliminated.
And in the excess allocation calculating part of the said 2nd Embodiment shown in FIG. 10, satisfy | filling the conditions of Formula (13)-(15) in step S530, and the solution with which the replacement amount (FFR + FFL) of front and rear wheels becomes the maximum. The calculation and the torque command value in step S540 are different.

First, step S530 will be described.
When the left and right difference is applied to the rear wheels, the braking force replacement amount of the front wheels is equal to the left and right, and therefore the braking torque front and rear replacement amount ΔT is expressed by the following equation.
FFR = FFL = ΔT / 2 (20)
The formula is developed based on the formula (20) and the above formulas (13) and (14), and the rear wheel braking force replacement amount is obtained as follows.
FRR = ΔT × (2LRL−LFL + LFR) / (2R × (LRL + LRR))
(21)
FRL = ΔT × (2LRR + LFL−LFR) / (2R × (LRL + LRR))
(22)

At this time, the front-rear change amount ΔT is not fixed. Using the constraint condition of (15), the front-rear change amount ΔT that maximizes the regeneration amount is obtained by the following method.
In this embodiment, in the front / rear ideal distribution before the front / rear replacement, it is assumed that the front / rear braking force has not reached the lock limit. Based on this premise, the braking amount is changed from the front wheel to the rear wheel. Therefore, after changing the braking amount with respect to the ideal distribution, the braking force decreases at the front wheel and increases at the rear wheel. The constraint condition is simplified as the following equation.
Simplified constraints
0 ≧ Tb0-FR−FFR × R (19.1)
0 ≧ Tb0-FL−FFL × R (19.2)
Tm0-RR + FRR x R ≥ max (FLMT-RR x R, Tmmax-RR)
(19.3)
Tm0-RL + FRL x R ≥ max (FLMT-RL x R, Tmmax-RL)
(19.4)

Then, the limit value ΔTlilm of the front and rear replacement amount in the conditional expressions (19.1) and (19.2) for the front wheels is obtained from the following expression in which the above expression (20) is substituted into the conditional expressions (19.1) and (19.2). calculate. However, since the ideal distribution of Tb0-FR and Tb0-FL are equal, Tb0-FR = Tb0-FL.
ΔTlim = 2 × Tb0-FR = 2 × Tb0-FL

Further, from Equations (21) and (22) and Equations (19.3) and (19.4), the maximum regenerative braking amount of the rear wheels and the limit value of the replacement amount due to the lock limit are calculated from the following equations.
(Replacement limit value due to maximum regenerative braking limit)
ΔTlim-tmmax1 = 2 (LRL + LRR) (Tmmax-RR-Td0-RR)
/ (2LRL-LFL + LFR)
ΔTlim-tmmax2 = 2 (LRL + LRR) (Tmmax-RL-Td0-RL)
/ (2LRR + LFL-LFR)
(Replacement amount limit value due to lock limit limitation)
ΔTlim-flim1 = 2 (LRL + LRR) (FLMT-RR × R-Td0-RR)
/ (2LRL-LFL + LFR)
ΔTlim-flim2 = 2 (LRL + LRR) (FLMT-RL × R-Td0-RL)
/ (2LRR + LFL-LFR)

  Here, in order to suppress the generation of a new yaw moment due to the replacement, the first control method of adding a left / right difference only by friction braking, the regenerative braking of the rear wheel, is used as a method of adjusting the braking force difference between the left and right rear wheels. There are three types: a second control method in which left and right can be controlled independently, and a second control method that gives a left-right difference only by regenerative braking, and a third control method that gives a left-right difference by both friction braking and regenerative braking. These three types have different constraints on the rear wheel braking force replacement amount. Hereinafter, a method of calculating the replacement amount that does not generate each yaw moment in the three types of control methods will be described individually.

"First control method (when making a left / right difference only by friction braking of the rear wheels)"
In order to suppress the yaw moment in the oversteer direction due to the change of the braking amount from the front wheel to the rear wheel during turning braking, the wheel on the turning outer wheel side is more absolute than the wheel on the turning inner wheel side when the left and right difference is applied to the rear wheel. As a large braking torque.
The limitation on the turning outer wheel side is that the sum of the left and right independent regenerative braking torque and the braking torque by friction braking does not exceed the lock limit. At this time, since the braking is also added to the braking, the maximum regenerative braking amount may be exceeded. On the other hand, the turning inner wheel side does not need to exceed the maximum regenerative braking amount, and the limitation is that the maximum regenerative braking amount and the lock limit value are not exceeded.

Based on this, the maximum value ΔT of the replacement amount is expressed by the following equation.
(When turning left)
ΔT = max (ΔTlim, ΔTlim-tmmax2, ΔTlim-flim1, ΔTlim-flim2)
(When turning right)
ΔT = max (ΔTlim, ΔTlim-tmmax1, ΔTlim-flim1, ΔTlim-flim2)

"Second control method (when making a left / right difference only by regenerative braking of the rear wheels)"
When the left / right difference is given only by the regenerative braking of the rear wheel, both the left and right wheels of the rear wheel do not exceed the maximum regenerative braking amount and the lock limit value. As a result, the maximum value ΔT of the replacement amount is expressed by the following equation.
ΔT = max (ΔTlim, ΔTlim-tmmax1, ΔTlim-flim1,
ΔTlim-tmmax2, ΔTlim-flim2)

"Third control method (when left and right difference is applied by rear wheel friction braking and regenerative braking)"
When making a left-right difference between the friction braking and regenerative braking of the rear wheels, the replacement amount ΔT when either one of the left and right rear wheels is the maximum regenerative braking amount and the other is the sum of the maximum regenerative braking amount and the friction braking is maximum. It becomes. Therefore, the maximum value ΔT of the replacement amount is expressed by the following equation.
ΔT = max (ΔTlim, min (ΔTlim-tmmax1, ΔTlim-tmmax2),
ΔTlim-flim1, ΔTlim-flim2)

Then, using the maximum value ΔT of the replacement amount when each control method is implemented, the braking replacement amount of each wheel is calculated based on the following equation.
FFR = FFL = ΔT / 2R
FRL = ΔT × (2LRR + LFL−LFR) / (2R (LRL + LRR))
FRR = ΔT × (2LRL−LFL + LFR) / (2R (LRL + LRR))

Next, the process of step S540 will be described.
In this step, correction is performed based on the replacement amount, and the final regenerative braking torque command value and fluid pressure braking torque command value for each wheel are calculated based on the following equations, and the process ends and returns.
(Regenerative braking torque command value)
Tm-RR = Tm-RR = Td0-RR + FRR × R
Fluid pressure braking torque command value)
Tb-FR = Tb0-FR -FFR x R
Tb-FL = Tb0-FL -FFL x R
Tb-RR = Td0-RR + FRR × R -Tm-RR
Tb-RL = Td0-RL + FRL x R-Tm-RL
As described above, a new yaw moment is generated in the oversteer direction during turning while changing the braking force from the front wheel to the rear wheel by making a difference in the left and right braking force on the rear wheel side that is a non-steered wheel. This can be suppressed or eliminated.

  FIG. 11 shows an example of changing the braking force between the front and rear wheels when the first control method is employed. FIG. 12 shows a configuration example of a vehicle when this control method is adopted. In this configuration example, friction braking can be applied to the four wheels independently, and regenerative braking independent of the left and right sides of the rear wheels can be applied.

FIG. 13 shows an example in which the braking force is changed between the front and rear wheels when the second control method is adopted. FIG. 14 shows a configuration example of a vehicle when this control method is adopted. In this configuration example, friction braking can be independently applied to the four wheels, and regenerative braking can be independently applied to the left and right of the rear wheels.
Other configurations, operations and effects are the same as those in the above embodiments.
As described above, the rear wheel side may be a steered wheel.

Next, a fourth embodiment will be described with reference to the drawings. In addition, about the components similar to said each embodiment, the same code | symbol is attached | subjected and demonstrated.
The basic configuration of this embodiment is the same as that of each of the above embodiments. However, a new yaw moment accompanying the replacement can be obtained by adjusting the braking force difference between the left and right front wheels and adjusting the braking force difference between the left and right rear wheels. The generation | occurrence | production of is suppressed or eliminated.

And in the excess allocation calculating part of the said 2nd Embodiment shown in FIG. 10, satisfy | filling the conditions of Formula (13)-(15) in step S530, and the solution with which the replacement amount (FFR + FFL) of front and rear wheels becomes the maximum. The calculation and the torque command value in step S540 are different.
First, step S530 will be described.
If the front and rear wheels are both left and right, the ratio of the left-right difference of the front wheel replacement amount to the total of the left-right difference of the front wheel and the left-right difference of the rear wheel is γ, and the left-right difference ratio of the rear wheel replacement amount is (1-γ). Then, the following formula is established.
(FFR−FFL) × (1−γ) = (FRR−FRL) × γ (30)
The ratio γ may be a fixed value according to the characteristics of the vehicle, or may be changed according to the steering angle and other values according to the behavior of the vehicle.

Then, when the formulas are developed based on the above formulas (13), (14) and (30), and the braking force replacement amount of the front and rear wheels is obtained, the following formula is obtained.
FFR = ΔT · (2γ × (LFL + LRR) − (LRL + LRR))
/ (2R · (γ × (LFL + LFR + LRL + LRR) − (LRL + LRR))
... (31.1)
FFL = ΔT · (2γ × (LFR + LRL) − (LRL + LRR))
/ (2R · (γ × (LFL + LFR + LRL + LRR) − (LRL + LRR))
... (31.2)
FRR = ΔT · (2γ × (LFR + LRL) − (2LRL−LFL + LFR))
/ (2R · (γ × (LFL + LFR + LRL + LRR) − (LRL + LRR))
... (31.3)
FRL = ΔT · (2γ × (LFL + LRR) − (2LRR−LFL + LFR))
/ (2R · (γ × (LFL + LFR + LRL + LRR) − (LRL + LRR))
... (31.4)
At this time, the front-rear change amount ΔT is not fixed. Using the constraint condition shown in (15) above, the front-rear change amount ΔT that maximizes the regenerative amount is obtained as follows.

In this embodiment, in the front / rear ideal distribution before the front / rear replacement, it is assumed that the front / rear braking force has not reached the lock limit. Based on this premise, the braking amount is changed from the front wheel to the rear wheel, so changing the braking amount with respect to the ideal distribution reduces the braking force on the front wheel and increases it on the rear wheel. The condition is simplified as shown in the following formula.
Simplified constraints)
0 ≧ Tb0-FR−FFR × R (32.1)
0 ≧ Tb0-FL −FFL × R (32.2)
Tm0-RR + FRR x R ≥ max (FLMT-RR x R, Tmmax-RR)
... (32.3)
Tm0-RL + FRL x R ≥ max (FLMT-RL x R, Tmmax-RL)
... (32.3)

Then, based on the following formula obtained by substituting the formulas (31.1) and (31.2) into the formulas (32.1) and (32.2), the front wheel condition formula (32.1) The limit values ΔTlim1 and ΔTlim2 of the front / rear replacement amount in (32.2) are calculated.
ΔTlim1 = 2Tb0-FR (γ × (LFL + LFR + LRL + LRR) − (LRL + LRR))
/ (2γ × (LFL + LRR) − (LRL + LRR))
ΔTlim2 = 2Tb0−FL (γ × (LFL + LFR + LRL + LRR) − (LRL + LRR))
/ (2γ × (LFR + LRL) − (LRL + LRR))

Further, based on the following formula obtained by substituting the formulas (31.3) and (31.4) into the formulas (32.3) and (32.4), the maximum regenerative braking amount of the rear wheel and the lock The limit value of the replacement amount due to the limit is calculated.
(Replacement limit value due to maximum regenerative braking limit)
ΔTlim-tmmax1 = 2 (γ · (LFL + LFR + LRL + LRR) − (LRL + LRR))
× (Tmmax-RR−Td0-RR)
/ (2γ · (LFR + LRL)-(2LRL-LFL + LFR))
ΔTlim-tmmax2 = 2 (γ · (LFL + LFR + LRL + LRR) − (LRL + LRR))
× (Tmmax-RL -Td0-RL)
/ (2γ · (LFR + LRL)-(2LRR + LFL-LFR))
(Replacement amount limit value due to lock limit limitation)
ΔTlim-flim1 = 2 (γ · (LFL + LFR + LRL + LRR) − (LRL + LRR))
× (FLMT-RR × R-Td0-RR)
/ (2γ · (LFR + LRL)-(2LRL-LFL + LFR))
ΔTlim-flim2 = 2 (γ · (LFL + LFR + LRL + LRR) − (LRL + LRR))
× (FLMT-RL × R-Td0-RL)
/ (2γ · (LFR + LRL)-(2LRR + LFL-LFR))

  Here, in order to suppress the generation of new yaw moments due to replacement, the difference between the braking force of the left and right front wheels and the method of adjusting the braking force difference of the left and right rear wheels are the same as for the left and right rear wheels only by friction braking. The first control method for attaching the rear wheel, the second control method for making a difference between the left and right rear wheels by making the regenerative braking of the rear wheel independently controllable on the left and right, and the left and right sides for both friction braking and regenerative braking There are three types of third control methods for making a difference in the rear wheels. These three types have different constraints on the rear wheel braking force replacement amount. Hereinafter, a method of calculating the replacement amount that does not generate each yaw moment in the three types of control methods will be described individually.

"First control method (when the rear wheel side is made only by friction braking and left / right difference)"
In order to suppress the yaw moment in the oversteer direction due to the change of the braking amount from the front wheel to the rear wheel during turning braking, the wheel on the turning outer wheel side is more absolute than the wheel on the turning inner wheel side when the left and right difference is applied to the rear wheel. As a large braking torque.
The limitation on the turning outer wheel side is that the sum of the left and right independent regenerative braking torque and the braking torque by friction braking does not exceed the lock limit. At this time, since the braking is also added to the braking, the maximum regenerative braking amount may be exceeded. On the other hand, the turning inner wheel side does not need to exceed the maximum regenerative braking amount, and the limitation is that the maximum regenerative braking amount and the lock limit value are not exceeded.

Based on this, the maximum value ΔT of the replacement amount is expressed by the following equation.
(When turning left)
ΔT = max (ΔTlim1, ΔTlim2, ΔTlim-tmmax2,
ΔTlim-flim1, ΔTlim-flim2)
(When turning right)
ΔT = max (ΔTlim1, ΔTlim2, ΔTlim-tmmax1,
ΔTlim-flim1, ΔTlim-flim2)

"Second control method (when rear wheel side is used only for regenerative braking and left / right difference)"
When the left / right difference is given only to the rear wheels only by regenerative braking, both the left and right rear wheels do not exceed the maximum regenerative braking amount and the lock limit value. As a result, the maximum value ΔT of the replacement amount is given by the following equation.
ΔT = max (ΔTlim1, ΔTlim2, ΔTlim-tmmax1, ΔTlim-flim1,
ΔTlim-tmmax2, ΔTlim-flim2)

“Third control method (when the rear wheel side is subjected to friction braking and regenerative braking)
In this case, for example, the vehicle configuration shown in FIG. 8 may be adopted.
When the left and right difference between the friction braking and regenerative braking is applied to the rear wheel, either the left or right rear wheel is the maximum regenerative braking amount, and the replacement amount ΔT is the maximum when the other is the sum of the maximum regenerative braking amount and the friction braking. It becomes. Therefore, the maximum value ΔT of the replacement amount is expressed by the following equation.
ΔT = max (ΔTlim1, ΔTlim2, min (ΔTlim-tmmax1, ΔTlim-tmmax2),
ΔTlim-flim1, ΔTlim-flim2)

Then, the braking replacement amount of each wheel is calculated based on the following equations (31.1) to (31.4) using the maximum value ΔT of the replacement amount when each control method is performed.
FFR = ΔT × (2LFL−LRL + LRR) / (2R × (LFL + LFR))
... (31.1)
FFL = ΔT × (2LFR + LRL−LRR) / (2R × (LFL + LFR))
... (31.2)
FRL = ΔT × (2LRR + LFL−LFR) / (2R (LRL + LRR))
... (31.3)
FRR = ΔT × (2LRL−LFL + LFR) / (2R (LRL + LRR))
... (31.4)

Next, the process of step S540 will be described.
In this step, correction is performed based on the replacement amount, and the final regenerative braking torque command value and fluid pressure braking torque command value for each wheel are calculated based on the following equations, and the process ends and returns.
(Regenerative braking torque command value)
Tm-RR = max (Td0-RR + FRR × R, Tmmax-RR)
Tm-RL = max (Td0-RL + FRL × R, Tmmax-RL)
Fluid pressure braking torque command value)
Tb-FR = Tb0-FR -FFR x R
Tb-FL = Tb0-FL -FFL x R
Tb-RR = Td0-RR + FRR × R -Tm-RR
Tb-RL = Td0-RL + FRL x R-Tm-RL

Next, the operation and effect of the above configuration will be described.
As described above, by making a difference in the left and right braking force on both the front and rear wheels, a new yaw moment is generated in the oversteer direction during turning when switching the braking force from the front wheel to the rear wheel. Can be suppressed or eliminated.
In particular, since the generation of a new yaw moment is suppressed by providing a difference between the left and right braking forces in both the front and rear wheels, generation of a new yaw moment in a wider range can be suppressed more effectively than in the above embodiments.

FIG. 15 illustrates a case where the left and right braking force difference is given by friction braking on the front wheel and the left and right braking force difference is given by regenerative braking on the rear wheel.
Other configurations, operations and effects are the same as those in the above embodiments.
As described above, the rear wheel side may be a steered wheel.
Here, in each of the above embodiments, since regenerative braking is performed on the rear wheel side, the new yaw moment resulting from the replacement is a yaw moment that causes an oversteer direction during turning, but Thus, when regenerative braking is performed on the front wheel side, the new yaw moment resulting from the replacement is a yaw moment that causes an understeer direction during turning.

Next, a fifth embodiment will be described with reference to the drawings. In addition, about the components similar to said each embodiment, the same code | symbol is attached | subjected and demonstrated.
The vehicle configuration of this embodiment is the configuration shown in FIG. That is, friction braking can be applied to all four wheels independently, and regenerative braking can be applied independently to the left and right of the front wheels.

  In this embodiment, the braking force is changed from the rear wheel to the front wheel. When turning braking is performed, as shown in FIG. 17, a new yaw moment (yaw moment in the understeer direction) is generated by changing the left and right regenerative braking forces of the front wheels according to the change. Is suppressed or eliminated. In this case, the process of the excess allocation calculation unit may be performed according to the second control method in the third embodiment.

Alternatively, as shown in FIG. 18, the difference between the left and right regenerative braking forces of the front wheels and the difference of the left and right in the friction braking of the rear wheels are suppressed or eliminated by generating a new yaw moment due to the replacement. In this case, the process of the excess allocation calculation unit may be performed according to the second control method in the fourth embodiment.
Here, even when regenerative braking is performed on the front wheel side, as described above, the difference between the left and right braking force is achieved by adopting the processes according to the various processes described in the first to fourth embodiments. By adding, generation of a new yaw moment due to replacement may be prevented.

1 is a schematic configuration diagram according to an embodiment of the present invention. It is a functional block diagram concerning embodiment based on this invention. It is a figure explaining the process of the regeneration cooperation controller which concerns on embodiment based on this invention. It is a figure which shows the structural example of the deceleration controller which concerns on embodiment based on this invention. It is a figure which shows the example of front-back distribution which concerns on embodiment based on this invention. It is a figure which shows the process of the excess allocation calculating part which concerns on 1st Embodiment based on this invention. It is a figure explaining the length of the arm of the moment concerning the embodiment based on the present invention. It is a figure which shows an example of the vehicle structure which concerns on embodiment based on this invention. It is a figure explaining the example of the effect | action and effect which concerns on 1st Embodiment based on this invention. It is a figure which shows the process of the excess allocation calculating part which concerns on 2nd Embodiment based on this invention. It is a figure explaining the example of an effect | action and effect which concerns on 3rd Embodiment based on this invention. It is a figure which shows an example of the vehicle structure which concerns on embodiment based on this invention. It is a figure explaining the example of an effect | action and effect which concerns on 3rd Embodiment based on this invention. It is a figure which shows an example of the vehicle structure which concerns on embodiment based on this invention. It is a figure explaining the example of an effect | action and effect which concerns on 4th Embodiment based on this invention. It is a figure which shows an example of the vehicle structure which concerns on embodiment based on this invention. It is a figure explaining the example of the effect | action and effect which concerns on 5th Embodiment based on this invention. It is a figure explaining the example of the effect | action and effect which concerns on 5th Embodiment based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake pedal 3 Master cylinder 4 Solenoid valve for fluid path switching 6 Solenoid valve for pressure increase 7 Solenoid valve for pressure reduction 10 Fluid pressure braking controller 11 Motor controller 12 Regenerative cooperative braking controller 13 Motor 17 Wheel cylinder 25 Battery

Claims (3)

Steering wheels that are paired on the left and right, and other wheels other than the steering wheels,
The braking of at least one of the steered wheel and the other wheels is performed by a regenerative braking unit that generates a braking force by applying an electrical load and a friction braking unit that generates a braking force by applying a frictional force. Independent braking means which can be implemented and can independently control each braking force to each of the left and right steering wheels and other wheels by at least one of the two braking means;
Distribution changing means for changing the distribution of the braking force to the steered wheels and the braking force to the other wheels while maintaining the same total braking force applied to all the wheels via the independent braking means. In a vehicle braking control device,
Steering detection means for detecting steering of the steered wheels,
When the distribution changing means determines that the steering wheel is steered, the distribution to the left and right steering wheels in the increase / decrease of the braking force on the steering wheel due to the distribution change is determined based on the steering of the steering wheel. between the braking force and the other wheel to the steering wheel, replacement of the braking force in order to give priority to the regenerative braking is carried out, left and right braking force difference is attached to the direction of suppressing the entailment vehicle behavior to the replacement of the braking force A braking control device for a vehicle comprising left and right wheel distribution adjusting means for adjusting in such a manner. The distribution changing means changes the distribution of the braking force to the steered wheels and the braking force to other wheels in a direction to increase the braking force by the regenerative braking means with respect to the ideal distribution state of the braking force. The vehicle braking control device according to claim 1 . The distribution changing means includes excess distribution means for replacing an excessive braking force with respect to one required braking force of a braking force to a steering wheel or a braking force to another wheel with the other braking force. The vehicle braking control device according to claim 1 or 2 .

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