JP2006246614A - Coordination controller of brake with combination system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coordination controller that can control fluctuations of the decelerating speed, that is generated when the friction braking of wheels is started during the coordination control of a brake with a combination system. <P>SOLUTION: In achieving target braking torque Tdcom that increases with the rise of master cylinder liquid pressure Pmc, it is achieved only by regeneration torque Tmcom of front wheels initially. During an instantaneous period of time from t1 to t2, when deviation becomes a set point Tm1 between Tmcom and permissible maximum regenerative braking torque Tmmax, a rear wheel friction braking torque Tbcomr is started slowly, by preliminarily increasing the pressure of non-regenerative wheels (rear wheels) whose friction braking should be started. The Tmcom is corrected, only by a portion of the braking torque accompanying this to compensate the target braking torque Tdcom. During an instantaneous period of time from t3 to t4, when deviation becomes a set point between a command value of basic rear wheel liquid pressure braking torque and target rear wheel braking torque, based on the ideal distribution of front and rear braking forces, front wheel friction braking torque is started slowly, by preliminarily increasing the pressure of regenerative wheels (front wheels) whose friction braking should be started. Tbcomr is corrected by only the portion of the braking torque that accompanies this and compensates the target braking toque Tdcom. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  INDUSTRIAL APPLICABILITY The present invention provides a combined brake cooperative control device that is provided with two types of brake devices, a regenerative braking device and a hydraulic braking device and an electric friction braking device, and in particular, can reduce deceleration fluctuations at the start of friction braking. The present invention relates to a combined brake cooperative control apparatus.

  As a composite brake, a combination of a regenerative braking device that generates braking force by converting wheel rotational energy into electric power by a motor / generator and a friction braking device that operates a friction brake unit of the wheel by brake fluid pressure or electromagnetic force A composite brake device is known as a representative.

As a cooperative control device for such a composite brake, for example, as described in Patent Document 1, for example,
The target braking torque required according to the driving state and driving state of the vehicle is realized by a combination of regenerative braking and friction braking,
Normally, in order to increase the energy recovery rate, a combination of regenerative braking and friction braking that exhausts the maximum possible regenerative braking torque is used, but as the vehicle speed decreases, the fine control accuracy of the braking torque by regenerative braking decreases. Then, the maximum possible regenerative braking torque is decreased to reduce the regenerative braking torque, and the friction braking torque is increased by that amount, so that the overall braking torque can maintain the target value. is there.

  In a vehicle with a composite brake, which has a regenerative braking device for the left and right front wheels, brakes the front wheels by regenerative braking and friction braking, and brakes the left and right rear wheels only by friction braking, the target braking torque of the vehicle is the master cylinder. In the case where the hydraulic pressure Pmc (the driver's braking operation state) is as shown by the solid line in FIG. 21, the cooperative control of the composite brake will be described.

While the master cylinder hydraulic pressure Pmc is low and the target braking torque is smaller than the maximum possible regenerative braking torque, the vehicle is braked only with the regenerative braking device attached to the front wheels, increasing the energy recovery efficiency. To improve fuel efficiency.
If the target braking torque increases beyond the maximum possible regenerative braking torque due to an increase in the master cylinder hydraulic pressure Pmc, the target braking torque cannot be achieved only by regenerative braking.Therefore, friction braking is added to regenerative braking to brake the vehicle. Do.

That is, first, the target drive torque is realized by cooperative control in which the friction braking torque of the rear wheel, which is a non-regenerative wheel, is added to the maximum possible regenerative braking torque.
If the target braking torque is further increased by further increasing the master cylinder hydraulic pressure Pmc, the friction braking torque of the front wheel, which is the regenerative wheel, is reduced from the request to realize the ideal front / rear wheel braking torque distribution in which the front and rear wheels are simultaneously locked. In addition to being added to the maximum possible regenerative braking torque, the target drive torque is realized by cooperative control that reduces the friction braking torque of the rear wheels.

When such cooperative control by braking torque distribution is performed, as shown in FIG. 22, the target braking torque Tdcom changes with time, and in this context, the target front wheel braking torque required to achieve the ideal front and rear wheel braking torque distribution Tdcomf is as shown in the figure, and the maximum possible regenerative braking torque Tmmax as shown in the figure is described as follows.
Rear wheel friction braking is started at the instant t1 during such braking, front wheel friction braking is started at the instant t2, front wheel friction braking is finished at the instant t3, rear wheel friction braking is finished at the instant t4, and rearward at the instant t5. Wheel friction braking is started, and front wheel friction braking is started at instant t6.
The caliper and the rotor that make up the friction braking unit repeat contact and non-contact many times during one braking with the brake pedal depressed once.

By the way, the response of the friction braking device is larger than that of the regenerative braking device, and the variation thereof is large. This tendency is particularly noticeable when friction braking is started from a state where the friction braking torque is zero.
Nevertheless, as described above, if the caliper and rotor that make up the friction braking unit repeat contact and non-contact many times during one braking operation when the brake pedal is depressed once, each time friction braking is started. There is a problem in that the fluctuation of the deceleration of the vehicle that occurs is frequently generated and the ride comfort of the vehicle is lowered.

On the other hand, as described in, for example, Patent Document 2, as a technique for preventing deceleration fluctuation caused by caliper / rotor opening / contact repeated during braking, a predetermined friction braking is always performed during braking. Technology was proposed.
This technique is as shown in FIG. 23 and FIG. 24 when shown as braking torque distribution under the same conditions as in FIG. 21 and FIG. 22, and in the hatching region of FIG. 24 where braking was performed only by regenerative braking. The main purpose is to continuously perform the friction braking of the front wheels and the rear wheels and limit the regenerative braking by that amount so that the total braking torque does not become excessive or insufficient with respect to the target braking torque Tdcom.
JP 2000-102108 A JP 11-049554 A

  However, in the prior art described in Patent Document 2, the actual total braking torque of the vehicle is excessive or insufficient with respect to the target braking torque Tdcom because the predetermined friction braking is always performed during braking even when only regenerative braking is originally performed. In view of the fact that it is essential to prevent the occurrence of the above, it is necessary to limit the regenerative braking torque by the friction braking torque in the hatched region of FIG.

Therefore, the amount of regenerative braking is reduced in the hatched region of FIG. 24, and there is a concern about deterioration of fuel consumption due to a decrease in energy recovery efficiency, and the target braking torque Tdcom is realized only by friction braking at the initial stage of braking operation. Thus, there is also a concern that the braking response delay at the start of the braking operation becomes large due to the fact that the response delay of the friction braking device is larger than that of the regenerative braking device.
Furthermore, since the response delay of the friction braking device has a large variation compared to that of the regenerative braking device, there is an unavoidable problem that deceleration fluctuations are more likely to occur in the initial stage of the braking operation than braking by only regenerative braking.

The present invention is based on the fact that the above-mentioned problems are not solved and that friction braking is always performed while braking only by regenerative braking is required.
The execution timing of friction braking is not changed, but instead, the change in braking torque at the start of friction braking is moderated, so that the above-mentioned problem related to deceleration fluctuation can be solved. An object is to provide a cooperative control device.

For this purpose, the cooperative control device for a composite brake according to the present invention is configured as described in claim 1.
First of all, I will explain the premised compound brake.
The target braking torque determined according to the driving state and driving state of the vehicle is realized by cooperation of regenerative braking and friction braking,
The target braking torque is distributed between the regenerative braking torque command value and the friction braking torque command value so that the regenerative braking torque does not exceed the maximum possible regenerative braking torque that is determined according to the driving state and driving state of the vehicle. Thus, the regenerative braking torque and the friction braking torque are controlled based on these command values.

The present invention relates to a composite brake of such a vehicle.
Friction braking torque command value change rate limiting means for limiting the rate of change of the friction braking torque command value related to the friction braking start wheel at the start of the friction braking;
The basic regenerative braking torque command value determined by the distribution and / or the basic friction braking related to other wheels other than the friction braking start wheel so that the change in the friction braking torque command value due to the change rate restriction is canceled out. The present invention is characterized in that a braking torque compensation means for compensating for vehicle braking torque by changing a torque command value is provided.

According to the composite brake cooperative control device of the present invention,
The friction braking torque command value change rate limiting means limits the rate of change of the friction braking torque command value related to the friction braking start wheel at the start of friction braking,
The basic regenerative braking torque command value and / or the basic related to other wheels other than the friction braking start wheel so that the braking torque compensation means cancels out the change in the friction braking torque command value due to the change rate limitation. In order to compensate the vehicle braking torque by changing the friction braking torque command value,
At the start of friction braking, the friction braking torque distribution of the friction braking starting wheel is reduced, and the regenerative braking torque and the friction braking torque related to the other wheels already braking other than the friction braking starting wheel are corrected to compensate for this. That means
As described above, the friction braking start wheel, which has a large response delay and the size of its variation, is caused by the response delay at the start of friction braking of the friction braking start wheel and its variation by the amount of friction braking torque distribution. Problems related to braking response delay and deceleration fluctuation can be solved.

Moreover, in order to achieve the above effect, the conventional method of always performing friction braking during braking is not adopted, but the execution timing of friction braking is not changed, and the braking torque at the start of friction braking is not changed. Because it was achieved by gradual change,
The above-described effects can be achieved without causing the above-described problem that the regenerative braking is greatly restricted and the energy recovery efficiency is lowered (fuel consumption is deteriorated) and the above-described problem related to the deceleration fluctuation.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 is a control system diagram of a composite brake having a cooperative control device according to an embodiment of the present invention. In this embodiment, the composite brake is shown as a wheel 1 (only one driving front wheel is shown in the figure). A hydraulic brake device (friction brake device) that generates a braking force by supplying hydraulic pressure to the wheel cylinder 2 provided in association with the wheel cylinder 2 and an AC synchronous motor 4 that is drivingly coupled to the driving front wheel 1 via a gear box 3. Thus, a combination with a regenerative braking device (regenerative braking device) that converts wheel rotational energy into electric power is configured.

  In such a composite brake, the cooperative control between the hydraulic brake device (friction brake device) and the regenerative brake device (regenerative brake device) is performed while the main brake force is obtained by controlling the regenerative braking torque by the AC synchronous motor 4. The purpose is to efficiently recover the regenerative energy by controlling the brake fluid pressure to the cylinder 2 to be reduced.

First, the hydraulic brake device will be described. Reference numeral 5 denotes a brake pedal that is depressed according to the braking force of the vehicle desired by the driver. The depression force of the brake pedal 5 is boosted by the hydraulic booster 6 and is the boosted force. It is assumed that when a piston cup (not shown) of the master cylinder 7 is pushed, the master cylinder 7 outputs a master cylinder hydraulic pressure Pmc corresponding to the depression force of the brake pedal 5 to the brake hydraulic pressure pipe 8.
In FIG. 1, the brake hydraulic pressure pipe 8 is connected only to the wheel cylinder 2 provided on one driving front wheel 1, but the other three wheels (the other driving front wheel, after two driven wheels) are not shown. Needless to say, it is also connected to a wheel cylinder related to the wheel.

The hydraulic booster 6 and the master cylinder 7 use the brake fluid in the common reservoir 9 as a working medium.
The hydraulic booster 6 includes a pump 10, which accumulates brake fluid sucked and discharged from the reservoir 9 in the accumulator 11, and sequence-controls the accumulator internal pressure by the pressure switch 12.
The hydraulic booster 6 boosts the pedal force of the brake pedal 5 using the pressure in the accumulator 11 as a pressure source, and pushes the piston cup in the master cylinder 7 with the boosted pedal force. The master cylinder 7 receives the brake fluid from the reservoir 9. In the brake pipe 8, a master cylinder hydraulic pressure Pmc corresponding to the brake pedal depression force is generated, and the wheel cylinder hydraulic pressure Pwc is supplied to the wheel cylinder 2 as an original pressure.

The wheel cylinder hydraulic pressure Pwc can be feedback controlled as will be described later using the accumulator internal pressure of the accumulator 11, and for this reason, an electromagnetic switching valve 13 is inserted in the middle of the brake pipe 8, and the wheel cylinder more than the electromagnetic switching valve 13. On the second side, a pressure increasing circuit 15 extending from the discharge circuit of the pump 10 and having a pressure increasing valve 14 inserted therein, and a pressure reducing circuit extending from the suction circuit of the pump 10 and having a pressure reducing valve 16 inserted into the brake pipe 8 on the second side. Each circuit 17 is connected.
The electromagnetic switching valve 13 opens the brake pipe 8 in a normal state to direct the master cylinder hydraulic pressure Pmc to the wheel cylinder 2, shuts off the brake pipe 8 when the solenoid 13 a is turned on, and connects the master cylinder 7 to the stroke simulator 26. Thus, a hydraulic load equivalent to that of the wheel cylinder 2 is applied, so that the brake pedal 5 can continue to be given the same operational feeling as usual.

The pressure increasing valve 14 normally opens the pressure increasing circuit 15 and increases the wheel cylinder hydraulic pressure Pwc by the pressure of the accumulator 11, but when the solenoid 14a is ON, the pressure increasing circuit 15 is cut off to increase the wheel cylinder hydraulic pressure Pwc. Pressure shall be discontinued,
The pressure reducing valve 16 normally shuts off the pressure reducing circuit 17, but when the solenoid 16a is ON, the pressure reducing circuit 17 is opened to reduce the wheel cylinder hydraulic pressure Pwc.
Here, the pressure increasing valve 14 and the pressure reducing valve 16 shut off the corresponding pressure increasing circuit 15 and the pressure reducing circuit 17 while the switching valve 13 opens the brake pipe 8, whereby the wheel cylinder hydraulic pressure Pwc is mastered. It is determined by the cylinder hydraulic pressure Pmc.

Further, while the pressure increasing valve 14 or the pressure reducing valve 16 is increasing or decreasing the wheel cylinder hydraulic pressure Pwc, the brake pipe 8 is shut off by turning on the switching valve 13 to be influenced by the master cylinder hydraulic pressure Pmc. Instead, the wheel cylinder hydraulic pressure Pwc can be increased or decreased by the pressure increasing valve 14 or the pressure reducing valve 16.
The switching valve 13, the pressure increasing valve 14, and the pressure reducing valve 16 are controlled by a hydraulic brake controller 18, and therefore, the controller 18 detects the master cylinder hydraulic pressure Pmc representing the vehicle braking force requested by the driver. A signal from the sensor 19 and a signal from the pressure sensor 20 for detecting the wheel cylinder hydraulic pressure Pwc representing the actual value of the hydraulic braking torque are input.

  The AC synchronous motor 4 that is drivingly coupled to the left and right driving front wheels 1 via the gear box 3 is subjected to AC / DC conversion in a DC / AC conversion current control circuit (inverter) 22 by a three-phase PWM signal from the motor torque controller 21. When the driving of the left and right front wheels 1 by the motor 4 is necessary, the wheel 1 is driven by the electric power from the DC battery 23. When the braking of the wheel 1 is necessary, the vehicle kinetic energy is obtained by regenerative braking torque control. The battery 23 is collected.

The hydraulic brake controller 18 and the motor torque controller 21 communicate with the composite brake coordination controller 24 and control the corresponding hydraulic braking device and regenerative braking device according to commands from the controller 24 as described later. .
The motor torque controller 21 controls the regenerative braking torque by the motor 4 based on the regenerative braking torque command value Tmcom from the composite brake coordination controller 24, and the driving torque control of the wheels 1 by the motor 4 when the left and right front wheels 1 are requested to be driven. To do.

Further, the motor torque controller 21 calculates the allowable maximum regenerative braking torque Tmmax0 allowed for the motor 4 determined by the state of charge of the battery 23, the temperature, and the like, and transmits a signal corresponding to the composite brake coordination controller 24.
For this reason, the composite brake coordination controller 24 receives signals related to the master cylinder hydraulic pressure Pmc and the wheel cylinder hydraulic pressure Pwc from the pressure sensors 19 and 20 via the hydraulic brake controller 18, as well as the wheel (left front wheel) 1. A signal from the wheel speed sensor 25 for detecting the wheel speed Vwfl is input, and further, the wheel speed Vwfr of the right front wheel (not shown), the wheel speed Vwrl of the left rear wheel (not shown), and the right rear wheel (not shown). 2) Input a signal related to the wheel speed Vwrr.

Based on these input information, the composite brake coordination controller 24 performs coordinated control of the composite brake by processing as shown in the functional block diagram of FIG. 2 and the flowcharts of FIGS.
FIG. 3 is a main routine that is repeatedly executed by a scheduled interrupt every 10 msec. First, in step S1, the master cylinder hydraulic pressure Pmc and the wheel cylinder hydraulic pressure Pwc of the wheel are calculated.
In the next step S2, the wheel speeds Vwfl, Vwfr, Vwrl, Vwrr of each wheel are measured to obtain an average value (average wheel speed) Vw, and the average wheel speed Vw is determined by the following transfer function Fbpf (s) The wheel deceleration (vehicle deceleration) αv is obtained through the band-pass filter shown in FIG.
Fbpf (s) = s / {(1 / ω ² ) s ² + (2ζ / ω) s + 1} (1)
s: Laplace operator However, actually, it is calculated using a recurrence formula obtained by discretization by Tustin approximation or the like.

In step S3, the allowable maximum regenerative braking torque Tmmax0 that can be achieved by the motor 4 is read from the high-speed communication reception buffer with the motor torque controller 21.
The allowable maximum regenerative braking torque Tmmax0 is determined by the motor torque controller 21 according to the charging rate of the battery 23, and the like.
In step S4, the target deceleration α _dem of the vehicle is calculated by the following equation using the master cylinder hydraulic pressure Pmc and the constant K1 corresponding to the vehicle specifications stored in advance in the ROM.
α _dem = Pmc × K1 (2)
Here, the deceleration is treated as a positive value.

Note that the vehicle target deceleration rate α _dem is not only determined by the physical quantity commanded by the driver by the master cylinder hydraulic pressure Pmc, but in vehicles equipped with an inter-vehicle distance control device and a vehicle speed control device, a physical quantity by automatic braking by these devices. Of course, it can be determined according to the above.

In step S5 of FIG. 3, a braking torque command value Tdff (braking torque feedforward compensation amount) necessary to realize the target deceleration rate α _dem is calculated using the feedforward compensator 51 of FIG. .
That is, first, the target deceleration rate α _dem is converted into a braking torque using a constant K2 determined by the vehicle specifications, and then the response characteristic Pm () of the control target vehicle 54 is converted into the characteristic Fref (s) of the reference model 52 in FIG. s) feedforward compensator for matching (phase compensator) 51, the target deceleration characteristic C _FF (s) represented by the following formula (alpha _dem) target deceleration through braking torque corresponding alpha _dem Braking torque command value Tdff (feed forward compensation amount) is obtained.
In practice, the braking torque command value Tdff (feedforward compensation amount) for the target deceleration rate α _dem is also discretized and calculated in the same manner as described above.
C _FF (s) ＝ Fref (s) / Pm (s) (3)
= (Tp · s + 1) / (Tr · s + 1) (4)
Tp: Time constant
Tr: Time constant
Pm: Vehicle model characteristics of the controlled vehicle
(Vehicle deceleration characteristics with respect to braking torque command value)

Next, in step S6, it is determined whether or not the brake pedal has been operated based on whether or not the master cylinder hydraulic pressure Pmc is not less than a minute set value. When the brake pedal is operated, in step S7, the following target deceleration is performed. with obtaining the braking torque command value Tdfb for alpha _dem (feedback compensation amount), finding a total braking torque command value Tdcom necessary to achieve the target deceleration alpha _dem.
In this embodiment, the deceleration controller is configured by a “two-degree-of-freedom control system” as shown in FIG. 8 and includes a feedback compensator 53 in addition to the feedforward compensator 51 and the reference model 52 described above. Shall.
Closed loop performance such as control stability and disturbance resistance is realized by the feedback compensator 53, and response to the target deceleration rate α _dem is basically realized by the feedforward compensator 51 (when there is no modeling error). Is done.
The first target deceleration alpha _dem is in calculating the feedback compensation amount Tdfb, obtains the reference model response deceleration alpha _ref through a reference model 52 having a characteristic Fref (s) represented by the following formula.
Fref (s) = 1 / (Tr · s + 1) (5)

Further, as shown in FIG. 8, a deceleration feedback deviation Δα between the reference model response deceleration α _ref and the actual deceleration αv of the control target vehicle 54 (see step S2) is obtained.
△ α = α _ref −αv ... (6)
Then, the deceleration feedback deviation Δα is passed through a feedback compensator 53 having a characteristic C _FB (s) expressed by the following equation to obtain a braking torque feedback compensation amount Tdfb.
C _FB (s) = (Kp · s + Ki) / s (7)
However, in this embodiment, this characteristic is realized by a basic PI controller, and the control constants Kp and Ki are determined in consideration of gain margin and phase margin.
Equations (5) and (7) are calculated by discretization in the same manner as described above.

Next, as shown in FIG. 8, the braking torque command value Tdff (feedforward compensation amount) for the target deceleration rate α _dem and the braking torque feedback compensation amount Tdfb are added together to obtain a total braking torque command value Tdcom. Ask.
Step S7 in FIG. 3 is to obtain the total braking torque command value Tdcom as described above, and therefore corresponds to the total braking torque command value calculating means 31 in FIG.

  While it is determined in step S6 that there is no brake pedal operation, in step S8, the braking torque feedback compensation amount Tdfb and the internal variable of the digital filter expressed by the equation (7) used when obtaining this are initialized to PI. Initialize the integral term of the controller.

In the next step S9 in FIG. 3, the allowable maximum regenerative braking torque Tmmax0 obtained in step S3 is limited based on the wheel speed average value (vehicle speed) Vw obtained in step S2, and is actually used for braking torque distribution. The maximum possible regenerative braking torque Tmmax is determined.
In this embodiment, in this embodiment, the regenerative braking torque limiting coefficient Kv is searched from the wheel speed average value Vw (vehicle speed) based on the map of the regenerative braking torque limiting coefficient Kv set as shown in FIG.
Tmmax = Tmmax0 × Kv ... (8)
The maximum possible regenerative braking torque Tmmax is obtained by calculating
Therefore, step S9 corresponds to the possible maximum regenerative braking torque setting means 32 in FIG.
In addition, the term “maximum possible regenerative braking torque” in this specification refers to the Tmmax itself obtained as described above,
In order to properly coordinate regenerative braking and friction braking during the operation of the anti-skid control device, the above Tmmax is reduced by a predetermined rule,
Including those that are set slightly smaller than the above Tmmax so as not to be affected by the actuator of the braking system or control variations,
It means all possible maximum regenerative braking torques that are arbitrarily set so as not to exceed the above Tmmax according to various circumstances.

The reason why the regenerative braking torque limit coefficient Kv is decreased as the vehicle speed decreases from the limit start vehicle speed as shown in FIG. 9 and is set to 0 below the limit end vehicle speed is that the creep control performance and regenerative braking torque control performance in the low vehicle speed range are This is because it is necessary to suppress regenerative braking in these vehicle speed ranges.
Further, in step S9, while the regenerative braking torque limit coefficient Kv is 1 and the maximum possible regenerative braking torque Tmmax is not limited to the allowable maximum regenerative braking torque Tmmax0, the maximum regenerative braking torque limit flag fTMLMT is shown to indicate this. Is set to 0, while the regenerative braking torque limit coefficient Kv is less than 1 and the maximum possible regenerative braking torque Tmmax is limited to the allowable maximum regenerative braking torque Tmmax0, the maximum regenerative braking torque limit flag fTMLMT is set to indicate this. It shall be set to 1 and used for the control described later.

In the next step S10, the above-mentioned total braking torque command value Tdcom (step S7), the basic regenerative braking torque command value Tmcom0, and the basic hydraulic pressure (friction) braking torque command for regenerative cooperative brake control. Allocation to the value Tbcom0.
Therefore, step S10 corresponds to the hydraulic pressure / regenerative braking torque distribution means 33 in FIG.
In FIG. 2, for the sake of convenience, the basic regenerative braking torque command value Tmcom0 is shown as the output of the hydraulic pressure / regenerative braking torque distribution means 33.
The basic hydraulic pressure (friction) braking torque command value Tbcom0 is further divided into a basic hydraulic braking torque command value Tbcom0f for the left and right front wheels (drive wheels) 1 and a rear wheel (driven wheel) (not shown). This is distributed to the basic hydraulic braking torque command value Tbcom0r.
In this embodiment, since the regenerative brake motor 4 is set only for the front wheel 1 as the drive wheel, the modes 1 and 2 described later when the normal braking force front-rear distribution is not disturbed and the normal braking force are described. Modes 3 and 4 described later occur when the front-rear distribution is lost.

First, the total braking torque command value Tdcom is distributed back and forth as usual based on the map data illustrated in FIG. 10 stored in advance to obtain the normal front wheel braking torque command value Tdcomf and the rear wheel braking torque command value Tdcomr. .
The normal front / rear braking torque distribution is a standard for when regenerative braking is not in progress, taking into account the prevention of rear wheel lock caused by front / rear wheel load movement during braking, stability of vehicle behavior, shortening of the braking distance, etc. This is the front / rear braking force distribution characteristic.

As shown below, the basic front wheel hydraulic braking torque command value Tbcom0f, the basic rear wheel hydraulic braking torque command value Tbcom0r, and the basic regenerative braking torque command value Tmcom0 for each of the following conditions (modes): Seeking to contribute to regenerative cooperative brake control.
(Mode 4)
When Tmmax ≥ (Tdcomf + Tdcomr): Regenerative braking only
Tbcom0f = 0
Tbcom0r = 0
Tmcom0 = Tdcomf + Tdcomr
(Mode 3)
When Tdcomf + Tdcomr> Tmmax ≧ Tdcomf: Regenerative braking + rear wheel hydraulic braking
Tbcom0f = 0
Tbcom0r = Tdcomf + Tdcomr−Tmmax
Tmcom0 ＝ Tmmax
(Mode 2)
When Tdcomf> Tmmax ≥ Slightly set value: Regenerative braking + Front / rear wheel hydraulic braking
Tbcom0f ＝ Tdcomf−Tmmax
Tbcom0r ＝ Tdcomr
Tmcom0 ＝ Tmmax
(Mode 1)
Other than above: Hydraulic braking only
Tbcom0f ＝ Tdcomf
Tbcom0r ＝ Tdcomr
Tmcom0 = 0

In the next step S11, the basic regenerative braking torque command value Tmcom0 and the front and rear wheel hydraulic braking torque command values Tbcom0f and Tbcom0r obtained as described above are converted into the maximum possible regenerative braking torque by the processing described later with reference to FIGS. The final regenerative braking torque command value Tmcom and the front and rear hydraulic pressure braking torque command values Tbcomf and Tbcomr are obtained by correcting Tmmax so as to achieve the object of the present invention.
Therefore, step S11 corresponds to the braking torque command value correcting means 34 in FIG.

In the next step S12, the front and rear wheel hydraulic braking is performed using the constant K3 based on the vehicle specifications stored in the ROM in advance based on the front and rear wheel hydraulic braking torque command values Tbcomf and Tbcomr obtained in step S11. The front and rear wheel cylinder hydraulic pressure command values Pbcomf and Pbcomr corresponding to the torque command values Tbcomf and Tbcomr are calculated by the following equations.
Pbcomf = (Tbcomf x K3)
Pbcomr = (Tbcomr x K3)
In FIG. 2, for the sake of convenience, the wheel cylinder hydraulic pressure command values Pbcomf and Pbcomr for the front and rear wheels are shown as the output of the braking torque command value correcting means 34.

In the final step S13, the composite brake controller 24 shown in FIG. 1 also shows the regenerative braking torque command value Tmcom obtained in step S11 and the front and rear wheel cylinder hydraulic pressure command values obtained in step S12 as described above. Pbcomf and Pbcomr are communicated to the motor torque controller 21 and the hydraulic brake controller 18, respectively.
The motor torque controller 21 controls the motor 4 through the inverter 22 so that the regenerative braking torque command value Tmcom is achieved, and the hydraulic brake controller 18 controls the fluid to the front wheel cylinder 2 through the control of the electromagnetic valves 13, 14, 16. The pressure is controlled to become the command value Pbcomf, and the rear wheel cylinder hydraulic pressure is similarly controlled to become the command value Pbcomr.

Hereinafter, the basic regenerative braking torque command value Tmcom0 and the front and rear wheel hydraulic braking torque command values Tbcom0f and Tbcom0r are corrected so that the object of the present invention is achieved in step S11 of FIG. Processing for obtaining the front and rear wheel hydraulic braking torque command values Tbcomf and Tbcomr will be described in detail with reference to FIGS.
First, in step S111 of FIG. 4, it is checked whether or not the maximum regenerative braking is limited in step S9 based on whether or not the maximum regenerative braking restriction flag fTMLMT (see step S9 in FIG. 3) is 1. To do.
Whether or not the maximum regenerative braking is determined to be not fTMLMT = 1 in step S111, whether or not the preliminary pre-pressure increase of the rear wheel targeted by the present invention is performed in step S112. Is determined by checking the first preliminary pressure increase mode RPREMDl of the rear wheel.
Here, as will be described later, the rear wheel first preliminary pressure increase mode RPRMDl is set to 0 before the rear wheel preliminary pressure increase is performed and is 1 while the rear wheel preliminary pressure increase is performed. When the preliminary pressure increase of the rear wheel is completed, it is set to 2.

During the rear wheel preliminary pressure increase or before the rear wheel preliminary pressure increase determined in step S112 that the rear wheel first preliminary pressure increase mode RPRMDl is not 2, in step S113, the basic regenerative braking torque command value Tmcom0 (step S10) and the maximum possible regenerative braking torque Tmmax (step S9), the excess regenerative braking torque (Tmcom0−Tmmax) is a positive value less than the set value Tm1 (hereinafter, the braking torque is set to a negative value). It is determined whether or not it is time to perform preliminary pressure increase for the rear wheels.
This time means during the instants t1 to t2 in FIG. 14 showing the braking torque distribution under the same conditions as in FIG. 21, and during this instant t1 to t2, the rear wheel preliminary pressure increase was started in step S114. As shown, the rear wheel first preliminary pressure increasing mode RPREMD1 is set to 1.

The set value Tm1 related to the excessive regenerative braking torque is a value obtained by converting the maximum value of the deceleration fluctuation range that cannot be felt by the driver into torque using the specification values of the rear wheel friction braking device.
The allowable deceleration fluctuation range that can be experienced by the driver changes as shown in Fig. 11 depending on the magnitude of the vehicle deceleration. First, the allowable deceleration fluctuation range is obtained from the vehicle deceleration, and this is converted into torque. Thus, the set value Tm1 related to the excessive regenerative braking torque is determined.

In the next step S115, the regenerative braking torque command value Tmcom is limited to an increase equivalent to the braking torque equivalent to the rear wheel preliminary pressure increase, and the regenerative braking torque command value Tmcom is a solid line between the instants t1 and t2 in FIG. Raise gently as shown by.
Actually, assuming that the braking torque change width by the rear wheel preliminary pressure increase per time is ΔTbr, the regenerative braking torque command value Tmcom is determined by the following equation.
Tmcom = Tmcom (previous value) + △ Tbr

Further, the braking torque change width ΔTbr by the rear wheel preliminary pressure increase per time is obtained by the following equation.
△ Tbr ＝ Kbr × △ Tbr0
Here, ΔTbr0 is a reference value of the braking torque change width ΔTbr by the rear wheel preliminary pressure increase per time, and is a braking torque change width that can be followed by the friction braking device.
Kbr is a rear wheel preliminary pressure increase limiting coefficient (0 ≦ Kbr ≦ 1). For example, based on a planned map as shown by a solid line in FIG. 12, the basic regenerative braking torque command value Tmcom0 and the maximum regeneration It is determined by searching from the surplus regenerative braking torque (Tmcom0−Tmmax), which is the difference from the braking torque Tmmax.

In the solid line in FIG. 12, the rear wheel preliminary pressure increase limiting coefficient Kbr is switched between 0 and 1 in a step-like manner when the surplus regenerative braking torque (Tmcom0−Tmmax) is the set value Tm1. The wheel preliminary pressure increase limiting coefficient Kbr may be adjusted according to the response characteristics of the friction braking device as indicated by a broken line.
In any case, the rear wheel preliminary pressure increase limiting coefficient Kbr becomes 0 while the excessive regenerative braking torque (Tmcom0−Tmmax) is equal to or larger than the set value Tm1, so that the rear wheel preliminary pressure increase is not performed due to ΔTbr = 0. When the surplus regenerative braking torque (Tmcom0−Tmmax) is less than the set value Tm1, the surplus regenerative braking torque (Tmcom0−Tmmax) increases toward 1 as the regenerative braking torque (Tmcom0−Tmmax) decreases, and the braking torque due to pre-rear pressure increase at the rear wheel It is assumed that the change width ΔTbr is increased toward the reference value ΔTbr0.

In the next step S116, the regenerative braking torque command value Tmcom determined in step S115 as described above is distributed and determined in step S10 in FIG. 3 as at the instant t2 in FIG. It is determined whether or not the rear wheel preliminary pressure increase may be completed depending on whether or not the value Tmcom0 has been reached.
While it is determined in step S116 that the regenerative braking torque command value Tmcom has reached the basic regenerative braking torque command value Tmcom0, that is, before the instant t2 in FIG. 14, it is determined that the rear wheel preliminary pressure increase should be continued. In the meantime, step S117 is skipped and the control proceeds directly to the rear wheel preliminary pressure increasing step S118. After the regenerative braking torque command value Tmcom reaches the basic regenerative braking torque command value Tmcom0 in step S116, that is, FIG. After determining that the rear wheel preliminary pressure increase may be completed at the instant t2, the control proceeds to step S118 via step S117.

  In step S117, the regenerative braking torque command value Tmcom is set to the same value as the basic regenerative braking torque command value Tmcom0, and the regenerative braking torque command value Tmcom is set as indicated by a solid line after the instant t2 in FIG. The rear wheel first preliminary pressure increasing mode RPREMD1 is set to 2 so as to indicate that preliminary pressure increasing is in progress.

In step S118, the front wheel hydraulic braking torque command value Tbcomf is set to the same value as the basic front wheel hydraulic braking torque command value Tbcom0f distributed in step S10 of FIG. 3, and the rear wheel hydraulic braking torque command value Tbcomr. Based on the basic rear wheel hydraulic braking torque command value Tbcom0r and the basic regenerative braking torque command value Tmcom0 allocated in step S10 of FIG. 3, and the following formula:
Tbcomr = Tbcom0r + (Tmcom0−Tmcom)
The rear wheel preliminary pressure increase is determined by
The rear wheel hydraulic braking torque command value Tbcomr obtained by this equation represents the difference between the solid line (regenerative braking torque command value Tmcom obtained in step S115) and the alternate long and short dash line between the instants t1 and t2 in FIG. The change rate of the rear wheel hydraulic braking torque command value Tbcomr is limited at the start of wheel hydraulic (friction) braking.
Therefore, step S118 corresponds to the friction braking torque command value change rate limiting means in the present invention.

Further, as described above, in step S115, the regenerative braking torque command value Tmcom is limited by the same amount of braking torque as the rear wheel preliminary pressure increase in step S118, and the regenerative braking torque command value Tmcom is set as shown in FIG. As shown by the solid line between the instants t1 and t2, it is gradually raised and corresponds to the braking torque compensation means in the present invention.
After performing the processes in steps S111 to S118 as described above, the control returns to step S112 in FIG.

When it is determined in step S113 that the surplus regenerative braking torque (Tmcom0-Tmmax) is greater than or equal to the set value Tm1 or is negative, control is performed when the rear wheel preliminary pressure increase is not required before the instant t1 or after the instant t2 in FIG. The process proceeds to step S119 to check whether or not the previous rear wheel preliminary pressure increase has been performed based on whether or not the rear wheel first preliminary pressure increase mode RPRMD1 is 1.
If it is during the rear wheel preliminary pressure increase, the control proceeds to step S115 and subsequent steps to continue the rear wheel preliminary pressure increase.

Before starting the rear wheel preliminary pressure increase determined in step S119 that the rear wheel preliminary pressure increase is not in progress, or after completing the rear wheel preliminary pressure increase determined in step S112 that the rear wheel first preliminary pressure increase mode RPRMDl is 2. If so, the control proceeds to step S1191 in FIG.
In step S1191, the basic rear wheel friction braking torque Tbcom0r distributed in step S10 of FIG. 3 is less than or equal to the braking torque increase ΔTbf per time by the front wheel preliminary pressure increase performed to achieve the object of the present invention ( It is determined whether or not the basic rear wheel hydraulic braking torque is a magnitude that can be reduced by an amount ΔTbf of braking torque increase due to the preliminary increase in front wheel pressure.

Here, the braking torque change width ΔTbf by the front wheel preliminary pressure increase per time is obtained by the following equation.
△ Tbf ＝ Kbf × △ Tbf0
ΔTbf0 is a reference value of the braking torque change width ΔTbf by the front wheel preliminary pressure increase per time, and is a braking torque change width that the friction braking device can follow.
Kbf is a front wheel preliminary pressure increase limiting coefficient (0 ≦ Kbf ≦ 1). For example, based on a planned map as shown by a solid line in FIG. 13, a basic rear wheel hydraulic braking torque command value Tbcom0r and This is determined by searching from the rear wheel braking torque shortage (Tbdom0r−Tdcomr), which is the difference from the target rear wheel braking torque Tdcomr based on the ideal front and rear wheel braking force distribution (FIG. 10).

In the solid line in FIG. 13, the front wheel preliminary pressure increase limiting coefficient Kbf is switched between 0 and 1 in a step-like manner when the rear wheel braking torque shortage (Tbdom0r−Tdcomr) is the set value Tb1. The front wheel preliminary pressure increase limiting coefficient Kbf may be adjusted according to the response characteristics of the friction braking device as indicated by a broken line.
In any case, the front wheel preliminary pressure increase limiting coefficient Kbf becomes 0 while the rear wheel braking torque shortage (Tbdom0r−Tdcomr) is equal to or larger than the set value Tb1, so that the front wheel preliminary pressure increase is not performed due to ΔTbf = 0. When the rear wheel braking torque shortage amount (Tbdom0r−Tdcomr) is less than the set value Tb1, the rear wheel braking torque shortage amount (Tbdom0r−Tdcomr) increases toward 1 as the rear wheel braking torque shortage amount decreases. It is assumed that the braking torque change width ΔTbf due to the is increased toward the reference value ΔTbf0.

The set value Tb1 relating to the rear wheel braking torque deficiency (Tbdom0r−Tdcomr) is obtained by torque-converting the maximum value of the deceleration change width that cannot be felt by the driver using the specification values of the friction braking device.
By the way, the allowable deceleration fluctuation range that can be experienced by the driver changes as shown in FIG. 11 depending on the magnitude of the vehicle deceleration. First, the allowable deceleration fluctuation range is obtained from the vehicle deceleration, and this is converted into torque. Thus, the set value Tb1 relating to the rear wheel braking torque shortage is determined.

If Tbcom0r ≤ △ Tbf, even if the front wheel preliminary pressure increase is performed, the increase in the front wheel braking torque can be compensated for by a decrease in the rear wheel hydraulic pressure, but if Tbcom0r> △ Tbf, the front wheel preliminary pressure increase Since the increase in braking torque when performed cannot be compensated by the decrease in rear wheel hydraulic pressure, the front wheel preliminary pressure increase should not be performed.
In step S1199, the basic regenerative braking torque command value Tmcom0 allocated in step S10 of FIG. 3 to the regenerative braking torque command value Tmcom, the front wheel hydraulic braking torque command value Tbcomf, and the rear wheel hydraulic braking torque command value Tbcomr, respectively. Then, the same values as the front wheel hydraulic braking torque command value Tbcom0f and the rear wheel hydraulic braking torque command value Tbcom0r are set, and the control is returned to step S12 of FIG.

When it is determined in step S1191 that Tbcom0r ≦ ΔTbf is possible, the following front wheel preliminary pressure increase, which is aimed by the present invention, is performed in steps S1193 to S1198.
First, in step S1192, it is determined by checking the front wheel first preliminary pressure increase mode FPREMDl whether the front wheel preliminary pressure increase has been performed or has been completed.
Here, as will be apparent from the following description, the front wheel first preliminary pressure increase mode FPREMDl is set to 0 before the front wheel preliminary pressure increase is performed, and is set to 1 while the front wheel preliminary pressure increase is performed. It shall be set to 2 when the preliminary pressure increase of the front wheel is completed.

In step S1193, the front rear wheel hydraulic braking torque command value Tbcom0r (step S1193) indicates that the front wheel first preliminary pressure increase mode FPREMDl is determined to be not 2 or before the front wheel preliminary pressure increase. S10) and the rear wheel braking torque shortage (Tbdom0r−Tdcomr), which is the difference between the ideal front and rear wheel braking force distribution and the target rear wheel braking torque Tdcomr (FIG. 10), is a positive value less than the set value Tb1. Then, it is determined whether or not it is time to perform front wheel preliminary pressure increase.
This time means during the instants t3 to t4 in FIG. 14 showing the braking torque distribution under the same conditions as in FIG. 21, and during this instant t3 to t4, it is confirmed that the front wheel preliminary pressure increase has started in step S1194. As shown, the front wheel first preliminary pressure increase mode FPREMDl is set to 1.

In step S1194, the basic regenerative braking torque command value Tmcom0 obtained by allocating in step S10 in FIG. 3 is set to the regenerative braking torque command value Tmcom, and the front wheel is compared with the rear wheel hydraulic braking torque command value Tbcomr. According to the preliminary pressure increase, an increase restriction is applied by the equivalent amount of braking torque, and the rear wheel hydraulic braking torque command value Tbcomr is gradually increased as shown by a two-dot chain line between instants t3 and t4 in FIG.
Actually, assuming that the change width of the braking torque by the front wheel preliminary pressure increase per time is ΔTbf, the rear wheel hydraulic braking torque command value Tbcomr is determined by the following equation.
Tbcomr = TBcomr (previous value) + △ Tbf

In the next step S1195, the rear rear hydraulic pressure braking torque command value Tbcomr obtained as described above in step S1194 is basically distributed and obtained in step S10 of FIG. 3 at the instant t4 of FIG. It is determined whether or not the front wheel preliminary pressure increase may be completed depending on whether or not the wheel hydraulic braking torque command value Tbcom0r has been reached.
While determining in step S1195 that the rear wheel hydraulic braking torque command value Tbcomr has reached the basic rear wheel hydraulic braking torque command value Tbcom0r, that is, before the instant t4 in FIG. While it is determined that it should be performed, step S1196 is skipped and the control proceeds directly to front wheel preliminary pressure increasing step S1197. In step S1195, the rear wheel hydraulic braking torque command value Tbcomr is the basic rear wheel hydraulic braking torque command value. After reaching Tbcom0r, that is, after determining that the front wheel preliminary pressure increase may be completed at the instant t4 in FIG. 14, the control proceeds to step S1197 via step S1196.

  In step S1196, the rear wheel hydraulic braking torque command value Tbcomr is set to the same value as the basic rear wheel hydraulic braking torque command value Tbcom0r, and the rear wheel hydraulic braking torque command value Tbcomr is set to one point after the instant t4 in FIG. Set the value as shown between the chain line and the two-dot chain line, and set the front wheel first preliminary pressure increase mode FPREMD1 to 2 to indicate that the front wheel preliminary pressure increase is in progress.

In step S1197, the front wheel hydraulic braking torque command value Tbcomf is divided into the basic front wheel hydraulic braking torque command value Tbcom0f and the rear wheel hydraulic braking torque command value Tbcom0r allocated in step S10 of FIG. Based on braking torque command value Tbcomr
Tbcomf = Tbcom0f + (Tbcom0r−Tbcomr)
The front wheel preliminary pressure increase is determined by
The front wheel hydraulic braking torque command value Tbcomf obtained by this formula represents the difference between the solid line (regenerative braking torque command value Tmcom set in step S1194) and the two-dot chain line between the instants t3 and t4 in FIG. The rate of change of the front wheel hydraulic braking torque command value Tbcomf is limited at the start of hydraulic (friction) braking.
Therefore, step S1197 corresponds to the friction braking torque command value change rate limiting means in the present invention.

In step S1194, as described above, the rear wheel hydraulic braking torque command value Tbcomr is limited by the same amount of braking torque as the front wheel preliminary pressure increase in step S1197, and the rear wheel hydraulic braking torque command value is set. Tbcomr is gradually increased as shown as the distance between the alternate long and short dash line between instants t3 and t4 in FIG. 14, and corresponds to the braking torque compensation means in the present invention.
After performing the processing in steps S1191 to S1197 as described above, control is returned to step S112 in FIG.

When it is determined in step S1193 that the rear wheel braking torque shortage amount (Tbcom0r−Tdcomr) is greater than or equal to the set value Tb1 or is negative, the front wheel preliminary pressure increase before instant t3 or after instant t4 in FIG. The control advances to step S1198 to check whether or not the previous front wheel preliminary pressure increase has been performed based on whether or not the front wheel first preliminary pressure increase mode FPREMD1 is 1.
If the front wheel preliminary pressure increase is in progress, control proceeds to step S1194 and subsequent steps to continue the front wheel preliminary pressure increase.
If it is before the start of the rear wheel preliminary pressure increase determined in step S1198 that the front wheel preliminary pressure increase is not in progress, or after completion of the front wheel preliminary pressure increase determined in step S1192 that the front wheel first preliminary pressure increase mode FPREMDl is 2. Is returned to step S12 in FIG.

4 and 5 is performed when the maximum regenerative braking restriction flag fTMLMT (step S9 in FIG. 3) is determined to be 0 in step S111 in FIG. 4 (the maximum regenerative braking restriction in step S9 in FIG. 3 is limited). If not) rear wheel front pressure increase and front wheel pressure increase processing,
When it is determined in step S111 of FIG. 4 that the maximum regenerative braking limit flag fTMLMT = 1 (when the maximum regenerative braking is limited), the rear wheel preliminary pressure increase and the front wheel preliminary pressure increase processing are performed as shown in FIGS. As shown in

The rear wheel preliminary pressure increasing process in FIG. 6 is the same as the rear wheel preliminary pressure increasing process in FIG. 4. Steps S112 to S119 in FIG. 4 correspond to steps S1111 to S1118 in FIG. The difference is that the rear wheel first preliminary pressure-increasing mode RPREMD1 in step S114, step S117, and step S119 is replaced with the rear wheel second preliminary pressure-increasing mode RPREMD2 in step S1111, step S1113, step S1116, and step S1118. Therefore, the description of FIG. 6 is omitted here to avoid redundant description.
Further, the front wheel preliminary pressure increasing process in FIG. 7 is the same as the front wheel preliminary pressure increasing process in FIG. 5. Steps S1191 to S1199 in FIG. 5 correspond to steps S11181 to S11189 in FIG. Since the front wheel first preliminary pressure-increasing mode FPREMD1 in steps S1194, S1196, and S1198 is different from step S11182, step S11184, step S11186, and step S11188 only in that the front wheel second preliminary pressure-increasing mode FPREMD2 is read. The description of FIG. 7 is omitted here to avoid duplication.

By the way, according to the combined brake cooperative control device of the present embodiment, the rear wheel hydraulic braking torque command at the start of the hydraulic pressure (friction) braking of the rear wheels (non-regenerative wheels) is performed between the instants t1 and t2 in FIG. Limiting the rate of change of the value Tbcomr, limiting the rate of change of the front wheel hydraulic braking torque command value Tbcomf at the time of starting the hydraulic pressure (friction) braking of the front wheel (regenerative wheel) as shown in FIG.
The basic regenerative braking torque command value Tmcom0 and / or the basics related to other wheels other than the friction braking starting wheel so that the change in friction braking torque due to the change rate limitation of the hydraulic braking torque command value Tbcomr or Tbcomf is offset. In order to compensate for vehicle braking torque by changing the typical friction braking torque command value Tbcom0f or Tbcom0r,
At the start of friction braking, the friction braking torque distribution of the friction braking starting wheel is reduced, and the regenerative braking torque and the friction braking torque related to the other wheels already braking other than the friction braking starting wheel are corrected to compensate for this. That means
The braking response caused by the response delay and the variation of the friction braking start wheel at the start of the friction braking is the same as the friction braking torque distribution amount of the friction braking start wheel having a large response delay or its variation is a problem. Problems related to delay and deceleration fluctuation can be solved.

Moreover, in order to achieve the above effect, the conventional method of always performing friction braking during braking is not adopted, but the execution timing of friction braking is not changed, and the braking torque at the start of friction braking is not changed. Because it was achieved by gradual change,
The above-described effects can be achieved without causing the above-described problem that the regenerative braking is greatly restricted and the energy recovery efficiency is lowered (fuel consumption is deteriorated) and the above-described problem related to the deceleration fluctuation.

The above operation and effect will be described in detail with reference to FIG. 15 showing an operation time chart under the same conditions as in FIG. 22.In the period A from the braking operation start time t0 to the instant t1, the target braking torque Tdcom is set only by regenerative braking. Since this is feasible, the vehicle is braked only by the regenerative braking torque command value Tmcom, and the friction braking torque command values Tbcomf and Tbcomr for the front and rear wheels are zero.
The regenerative braking torque command value Tmcom approaches the maximum possible regenerative torque Tmmax as the target brake torque Tdcom increases as shown in the figure, but the maximum possible regenerative torque Tmmax and the regenerative braking torque command value Tmcom (this area) Is equal to the basic regenerative braking torque command value Tmcom0) (Tmcom0 – Tmmax) is smaller than the set value Tm1, and during the period B from the instant t1, the regenerative braking torque command value Tmcom increases and the rear wheel preliminary pressure increase The amount of increase in braking torque is limited by the above-mentioned, and the friction braking of the rear wheels is performed by the preliminary pressure increase by the amount of increase in braking torque.

This limit is achieved by compensating for the increase ΔTbr in the rear wheel hydraulic braking torque command value Tbcomr at the start of such rear wheel friction braking, and by compensating the accompanying change in braking torque ΔTbr by correcting the regenerative braking torque command value Tmcom. As is clear from FIG. 16 (b) showing the operation time chart when compensation is not performed and FIG.
The response delay at the start of friction braking of the friction braking start wheel (rear wheel) is reduced by the amount of friction braking torque distribution of the friction braking start wheel (rear wheel) whose large response delay or variation is a problem. In addition, problems related to braking response delay and deceleration fluctuation due to the variation thereof can be solved.
Further, the limit amount of the regenerative braking torque command value Tmcom is set to a coefficient Kbr (see FIG. 12), with the braking torque change width reference value ΔTbr0 by the rear wheel preliminary pressure increase that the friction braking device can follow as in step S115 as the maximum value. ), The response delay of the friction braking device can be kept small.

Also, when the regenerative braking torque deviation between the regenerative braking torque command value Tmcom and the maximum possible regenerative braking torque Tmmax becomes smaller than the set value Tm1 according to the braking state, the friction braking start wheel (rear wheel) is frictionally After the friction braking torque command value Tbcomr of the relevant wheel rises under the change rate limit of ΔTbr so as to start generating braking torque, after this friction braking torque command value Tbcomr becomes the basic friction braking torque command value Tbcom0r, The friction braking torque command value Tbcomr of the friction braking start wheel (rear wheel) is set to the basic friction braking torque command value Tbcom0r,
The basic regenerative braking torque command value Tmcom0 is corrected by the amount corresponding to the friction braking torque command value equivalent to the friction braking torque command value (rear wheel) of the friction braking starting wheel (rear wheel) rising under the change rate limit.
In the region where the response delay of the friction braking device is likely to occur or in the region where this response delay varies greatly, the distribution to the rear wheel friction braking itself is reduced, and the effect on the deceleration is reduced even if the response delay occurs. Is possible.

  Regardless of the control described above, the friction braking torque of the friction braking starting wheel (rear wheel) in the period Δt1 after the regenerative braking torque command value Tmcom reaches the maximum possible regenerative braking torque command value Tmmax as shown in FIG. 17 (a). The above operation and effect are shown below in FIG. It will be described in detail.

When the braking torque is distributed as shown in Fig. 17 (a) so that the regenerative braking torque is used preferentially, when the required braking torque Tdcom exceeds the maximum possible regenerative braking torque Tmmax, the shortage between the two (Tdcom- Tmmax) must be realized by friction braking.
In this case, in the normal distribution, the distribution to the friction braking is performed regardless of the response delay of the friction braking device and the large variation thereof, so that the vehicle deceleration fluctuation is likely to occur.
In addition, after the regenerative braking torque has already been used as described above, the increase of the friction braking torque command value Tbcomr of the friction braking start wheel (rear wheel) is restricted during the period Δt1 from the moment when the friction braking is started, and the braking torque is thereby increased. When the regenerative braking torque command value Tmcom is corrected to compensate for the change, the regenerative braking torque command value Tmcom has already reached the maximum possible value Tmmax and cannot be increased. As shown in the frame portion, the friction braking to be realized is limited, and the required braking torque cannot be realized accurately and accurately.

In contrast, in this embodiment, as shown in FIG. 17 (a), the regenerative braking torque deviation between the regenerative braking torque command value Tmcom and the maximum possible regenerative braking torque Tmmax is smaller than the set value Tm1 corresponding to the braking state. The friction braking torque command value Tbcomr of the wheel is set to ΔTbr so that the friction braking starting wheel (rear wheel) starts generating the friction braking torque during the period Δt2 from when the required braking torque reaches the maximum regenerative braking torque. Since the regenerative braking torque command value Tmcom is corrected to compensate for the braking torque change caused by rising under the change rate limit of
As shown in the dotted line circle frame in FIG. 17 (b), in the region Δt2 where the response delay of the friction braking device is likely to occur and in the region Δt2 where the response delay greatly varies, the distribution itself to the rear wheel friction braking is small. Therefore, the regenerative braking torque command value Tmcom can be increased below the maximum possible value Tmmax, so that the required braking torque can be accurately realized even if a response delay occurs, and deceleration fluctuations can be reduced. .

In addition, since the rear wheel preliminary pressure increase limiting coefficient Kbr used when determining the torque change width ΔTbr due to the rear wheel preliminary pressure increase in step S115 or step S1114 is determined as illustrated in FIG.
The larger the deviation between the maximum possible regenerative braking torque Tmmax and the basic regenerative braking torque command value Tmcom0, that is, the larger the regenerative braking torque (Tmcom0-Tmmax), the smaller the non-regenerative wheel (rear wheel) friction braking torque command value Tbcomr. To be
The braking torque distribution to the rear-wheel friction braking device can be gradually changed by changing from the solid line shown in FIG. 18 to the one shown by the wavy line, and the deceleration fluctuation at the start of friction braking can be further reduced. In addition, the limit amount of the regenerative braking torque can be further reduced by the hatched region in FIG. 18, and the energy recovery rate can be increased.

When the target braking torque Tdcom further increases after the period B in FIG. 15 due to the increase of the braking operation force, the rear wheel fluid is reduced in the period C from the instant t3 when the rear wheel braking torque shortage (Tbcom0r−Tbcomr) becomes smaller than the set value Tb1. The pressure braking torque command value Tbcomr is limited to increase by the amount of increase in the braking torque by the front wheel preliminary pressure increase, and the front wheel is made to perform the preliminary pressure increase (change rate limitation) by the amount of increase in the braking torque.
As a result, the ratio of the front wheel braking torque, which is the sum of the regenerative braking torque command value Tmcom and the front wheel friction braking torque command value Tbcomf, and the rear wheel friction braking torque command value Tbcomr at the instant t4 in FIG. However, also during this period C, the same effect as described above can be achieved.

  By the way, as shown in the round frame part of Fig. 19 (a), when the front wheel pre-pressure increase (change rate limit) is started from the instant t3 when the ideal front / rear wheel braking force distribution has been reached, the front wheel (regenerative wheel) friction braking is applied. Since there is a response delay from the start of allocation until the friction braking device actually functions, until the timing at which it is not necessary to limit the rate of change in front wheel friction braking, the front wheel (regenerative wheel) braking torque is still excessively distributed. Then, there is a problem that the front wheel braking torque excessive distribution state is maintained until the front and rear wheel braking force ideal distribution is restored.

However, according to the present embodiment, as shown in the period C of FIG. 15 and as indicated by the round frame portion of FIG. 19 (b), the rear wheel braking torque shortage amount (Tbcom0r−Tbcomr) is less than the set value Tb1. From the moment t3 when it becomes smaller, the increase in the rear wheel hydraulic braking torque command value Tbcomr is limited by the braking torque increase ΔTbf due to the front wheel preliminary pressure increase, and the front wheels are preliminarily increased (change rate limitation) by this braking torque increase ΔTbf. Furthermore, because the braking torque increase ΔTbf due to the front wheel preliminary pressure increase is set according to the response characteristics of the friction braking device,
As is apparent from FIG. 19 (b), the response delay of the friction braking device at the start of the front wheel friction braking and the fluctuation in the deceleration due to the large variation can be reduced.

  Further, according to this embodiment functioning in this way, as shown in the round frame portion of FIG. 19 (b), the rate of change is notwithstanding the response delay until the front wheel friction braking device actually starts the response. The front and rear wheel braking torque distribution can be returned to the ideal distribution at the instant t4 when the restriction is no longer necessary, and the time required for excessive distribution of the front wheel (regenerative wheel) braking torque can be shortened.

Further, as shown in FIG. 13, a basic rear wheel friction braking torque command value Tbcom0r is used as a front wheel preliminary pressure increase limiting coefficient Kbf used when determining the torque fluctuation range ΔTbf due to the front wheel preliminary pressure increase in step S1194 and step S11184. Since it is determined according to the deviation from the target rear wheel braking torque command value Tdcomr determined to be ideal front and rear wheel braking torque distribution,
By changing the regeneration limit line from the wavy line shown in FIG. 20 to the solid line, it is possible to further gradually distribute the braking torque to the front wheel friction braking, further reducing the deceleration fluctuation at the start of the front wheel friction braking. It is possible.

In addition, in a composite brake that performs regenerative coordination, it is necessary to limit regenerative braking as the vehicle speed decreases and shift to friction braking from the standpoint of creep control and regenerative braking torque control performance at low vehicle speeds. .
When the regenerative braking torque is limited in this way, as in the regenerative braking torque limiting region of FIG. 15, the distribution state of the braking torque changes from regenerative braking only (t5 to t6) to regenerative braking and rear wheel friction braking (t7 to t7). t8), regenerative braking, front and rear wheel friction braking (t8 to t9), and friction braking only (after t9).
In this change, the start of the rear wheel friction braking occurs at the instant t6, and the start of the front wheel friction braking occurs at the instant t8. Even at the start of the friction braking, the control shown in FIGS. In the period D, the rear wheel pre-boosting is shown as a change with time in the rear wheel friction braking torque command value Tbcomr, and in the E period from the instant t8, it is shown as the time change in the front wheel friction braking torque command value Tbcomf. The same effect as described above can be achieved through the preliminary pressure increase of the front wheel.

It is a control system figure of the compound brake provided with the cooperation control device which becomes one example of the present invention. It is a block diagram according to function which shows the control content which the composite brake cooperation controller in the cooperative control apparatus of the composite brake performs. It is a flowchart which shows the main routine of the cooperative control program which the composite brake cooperation controller performs. It is a flowchart which shows a part of subroutine concerning the calculation process of the regenerative braking torque command value and the friction braking torque command value in the cooperative control program. It is a flowchart which shows a part of other subroutine regarding the calculation process of the regenerative braking torque command value and the friction braking torque command value in the cooperative control program. It is a flowchart which shows further another part of the subroutine regarding the calculation process of the regenerative braking torque command value and the friction braking torque command value in the cooperative control program. It is a flowchart which shows another part of the subroutine regarding the calculation process of the regenerative braking torque command value and the friction braking torque command value in the cooperative control program. It is a block diagram which illustrates the deceleration controller of a vehicle. It is a diagram which shows the change characteristic of the limiting coefficient of regenerative braking torque. FIG. 10 is a characteristic diagram illustrating normal braking torque ideal front-rear distribution characteristics. It is a diagram which illustrates the change characteristic of the allowable deceleration fluctuation range. It is a diagram which shows the change characteristic of a rear-wheel preliminary | backup pressure increase limiting coefficient. It is a diagram which shows the change characteristic of a front wheel preliminary | backup pressure increase limiting coefficient. FIG. 6 is a characteristic diagram showing a braking torque distribution change with respect to a master cylinder hydraulic pressure when a regenerative braking torque command value and a friction braking torque command value are obtained by the control program of FIGS. 4 and 5. 4 is an operation time chart of cooperative control by the control program of FIG. Fig. 3 is an operation time chart showing the reduction effect of deceleration change when cooperative control by the control program of Fig. 3 is performed. (A) is an operation time chart when conventional cooperative control is performed, and (b) is a diagram. 6 is an operation time chart when cooperative control is performed by the control program of FIG. In the operation time chart shown in comparison between the timing when the preliminary pressure increase of the friction braking start wheel is performed when the cooperative control by the control program of FIG. 3 is performed and when it is different from this, (a) is an operation time chart when the preliminary pressure increase is performed at the conventional timing, and (b) is an operation time chart when the preliminary pressure increase is performed at the timing according to the control program of FIG. 4 is an operation time chart showing a gradual friction braking torque change when cooperative control is performed by the control program of FIG. In the operation time chart shown in comparison between the timing when the preliminary pressure increase of the friction braking start wheel is performed when the cooperative control by the control program of FIG. 3 is performed and when it is different from this, (a) is an operation time chart when the preliminary pressure increase is performed at the conventional timing, and (b) is an operation time chart when the preliminary pressure increase is performed at the timing according to the control program of FIG. 4 is an operation time chart showing a gradual friction braking torque change when cooperative control is performed by the control program of FIG. It is a characteristic diagram which shows the change condition of the braking torque distribution with respect to the master cylinder hydraulic pressure at the time of performing the conventional cooperative control. FIG. 22 is an operation time chart showing a time-series change in braking torque distribution when the cooperative control of FIG. 21 is performed. It is a characteristic diagram which shows the change condition of the braking torque distribution with respect to the master cylinder hydraulic pressure at the time of performing another conventional cooperative control. FIG. 24 is an operation time chart showing a time-series change in braking torque distribution when the cooperative control of FIG. 23 is performed.

Explanation of symbols

1 wheel 2 wheel cylinder 3 gear box 4 AC synchronous motor (regenerative brake device)
5 Brake pedal 6 Hydraulic booster 7 Master cylinder 8 Brake hydraulic piping 9 Reservoir
10 Pump
11 Accumulator
12 Pressure switch
13 Solenoid switching valve
14 Booster valve
15 Booster circuit
16 Pressure reducing valve
17 Pressure reducing circuit
18 Hydraulic brake controller
19 Pressure sensor
20 Pressure sensor
21 Motor torque controller
22 DC / AC conversion current control circuit (inverter)
23 DC battery
24 Combined brake coordination controller
25 Wheel speed sensor
26 Stroke simulator
31 Total braking torque command value calculation means
32 Maximum regenerative braking torque setting means
33 Fluid pressure / regenerative braking torque distribution means
34 Braking torque command value correction means

Claims (5)

The target braking torque determined according to the driving state and driving state of the vehicle is realized by cooperation of regenerative braking and friction braking,
The target braking torque is distributed between the regenerative braking torque command value and the friction braking torque command value so that the regenerative braking torque does not exceed the maximum possible regenerative braking torque that is determined according to the driving state and driving state of the vehicle. In the composite brake of the vehicle in which the regenerative braking torque and the friction braking torque are controlled based on these command values,
Friction braking torque command value change rate limiting means for limiting the rate of change of the friction braking torque command value related to the friction braking start wheel at the start of the friction braking;
The basic regenerative braking torque command value determined by the distribution and / or the basic friction braking related to other wheels other than the friction braking start wheel so that the change in the friction braking torque command value due to the change rate restriction is canceled out. A combined brake cooperative control device, comprising: a braking torque compensating means for compensating for vehicle braking torque by changing a torque command value. The cooperative control device for a composite brake according to claim 1, wherein the distribution is performed so that a regenerative braking torque command value is as large as possible within a range not exceeding the maximum possible regenerative braking torque.
The friction braking torque command value change rate limiting means is configured to perform friction braking when a regenerative braking torque deviation between the regenerative braking torque command value and the maximum possible regenerative braking torque becomes smaller than a predetermined value corresponding to a braking state. The friction braking torque command value of the friction braking starting wheel rises under the change rate limit so that the starting wheel starts to generate friction braking torque, and the friction braking torque command value of the friction braking starting wheel determined by the distribution is After the basic friction braking torque command value is reached, the friction braking torque command value of the friction braking start wheel is changed to the basic friction braking torque command value.
The braking torque compensation means corrects the basic regenerative braking torque command value determined by the distribution by an amount corresponding to the friction braking torque command value of the friction braking start wheel rising under the change rate limit. A coordinated control system for a composite brake. As the target braking torque increases, the target braking torque is sequentially distributed only to the regenerative braking torque command value, and is distributed to the regenerative braking torque command value and the non-regenerative wheel friction braking torque command value. The cooperative control device for a composite brake according to claim 1 or 2, wherein the regenerative wheel friction braking torque command value and the regenerative wheel friction braking torque command value are distributed.
The friction braking torque command value change rate limiting means is configured such that a non-regenerative wheel braking torque deviation between a non-regenerative wheel braking torque command value to be targeted and a non-regenerative wheel friction braking torque command value is a predetermined value corresponding to a braking state. The regenerative wheel friction braking torque command value is raised under the change rate limit so that the regenerative wheel starts to generate friction braking torque from the time when the regenerative wheel becomes smaller, and this regenerative wheel friction braking torque command value is determined by the distribution. After the basic regenerative wheel friction braking torque command value of the regenerative wheel, the regenerative wheel friction braking torque command value becomes the basic regenerative wheel friction braking torque command value.
The braking torque compensation means corrects the basic non-regenerative wheel friction braking torque command value determined by the distribution by an amount corresponding to the friction braking torque command value of the regenerative wheel rising under the change rate limit. The combined brake cooperative control device. The cooperative control device for a composite brake according to claim 3,
The friction braking torque command value change rate limiting means decreases the non-regenerative wheel friction braking torque command value as the regenerative braking torque deviation between the regenerative braking torque command value and the maximum possible regenerative braking torque increases. A coordinated control system for a composite brake. The cooperative control device for a composite brake according to claim 3,
The composite brake is such that the larger the non-regenerative wheel braking torque deviation between the non-regenerative wheel braking torque to be targeted and the non-regenerative wheel friction braking torque command value, the smaller the regenerative wheel friction braking torque command value. Coordinated control device.

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