JP2001088684A - Braking force distribution controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking force distribution controller favorably controlling a braking force distribution even in cases of detecting abnormality in a sensor, etc. SOLUTION: A vehicle is provided with wheel speed sensors 41, 42, 43, 44, a stop switch 45, and an acceleration sensor 46. The traveling state of the vehicle is detected by the sensors, etc., 41-46. Where at least one abnormality is detected in the sensors, etc., 41-46, a braking force distribution is backup controlled according to the traveling state of the vehicle detected by the residual normal sensors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force distribution control device for adjusting a braking force of a rear wheel to a predetermined relationship with a braking force of a front wheel.

[0002]

2. Description of the Related Art Conventionally, as a braking force distribution control device, for example, one described in Japanese Patent Application Laid-Open No. Hei 6-211116 is known. In such a braking force distribution control device, the braking force of the rear wheels with respect to the braking force of the front wheels is adjusted in a predetermined relationship according to detection signals from various sensors and the like provided in the vehicle.

[0003] By such control, the rising gradient of the braking force of the rear wheels is suppressed, and early locking of the rear wheels is prevented.

[0004]

In this braking force distribution control device, when an abnormality is detected in a sensor or the like provided for the control, the braking force distribution control is prohibited and the control is shifted to the normal brake. ing. In other words, if an abnormality such as a sensor is detected during the braking force distribution control, the control is immediately stopped, and if an abnormality such as the sensor is detected when the braking force distribution control is not performed. The start of the control is prohibited.

[0005] Therefore, in such a braking force distribution control device, when an abnormality of a sensor or the like is detected, the stability of the vehicle particularly in a high G region is impaired. An object of the present invention is to provide a braking force distribution control device that can appropriately perform braking force distribution control even when abnormality of a sensor or the like is detected.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises a plurality of running state detecting means for detecting a running state of a vehicle, and the running state is detected by the detected running state. In the braking force distribution control device that performs braking force distribution control in accordance with the above, when at least one abnormality of the traveling state detecting means is detected, the braking state is controlled according to the traveling state detected by the remaining normal traveling state detecting means. The gist is to provide backup control of the braking force distribution.

According to a second aspect of the present invention, in the braking force distribution control device according to the first aspect, the backup control sets a detection value of the traveling state detection means in which the abnormality is detected to a predetermined value. The point is to do it.

According to a third aspect of the present invention, in the braking force distribution control device according to the second aspect, the predetermined value set by the traveling state detecting means in which the abnormality is detected is set to a value on the side to which more braking force is applied. It should be a value.

According to a fourth aspect of the present invention, there is provided the braking force distribution control device according to the first aspect, further comprising an anti-skid control means for performing an anti-skid control, wherein the backup control includes a driving state in which the abnormality is detected. The gist is anti-skid control performed by setting the detection value of the detection means to a predetermined value.

According to a fifth aspect of the present invention, in the braking force distribution control device according to the fourth aspect, the predetermined value set by the traveling state detecting means in which the abnormality is detected is set to a value on the side to which more braking force is applied. It should be a value.

According to the first aspect of the present invention, when at least one abnormality of the traveling state detecting means is detected, the traveling state detected by the remaining normal traveling state detecting means is detected. Backup control of the braking force distribution is performed according to the state. Therefore, in such a case, the stability of the vehicle, particularly in the high G region, is ensured as compared with, for example, the control in which the braking force distribution control is prohibited.

According to the second aspect of the present invention, the calculation load of the microcomputer is increased by an extremely simple method of setting the detection value of the traveling state detecting means in which the abnormality is detected to a predetermined value. And the braking force distribution is controlled by backup.

According to the third aspect of the present invention, the predetermined value at which the detected value of the traveling state detecting means in which the abnormality is detected is set to a value on the side to which the braking force is more applied. Therefore, insufficient braking force in the backup control is prevented.

According to the fourth aspect of the present invention, in the braking force distribution control device having the anti-skid control means, the detected value of the traveling state detecting means in which the abnormality is detected is set to a predetermined value, and the anti-skid is controlled. With the extremely simple method of performing the control, the braking force distribution is back-up controlled without increasing the calculation load of the microcomputer.

According to the fifth aspect of the present invention, the predetermined value at which the detected value of the traveling state detecting means in which the abnormality is detected is set to a value on the side to which the braking force is further applied. Therefore, insufficient braking force in the backup control is prevented.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a braking force distribution control device embodying the present invention will be described below with reference to FIGS.

FIG. 1 is an overall configuration diagram of a brake fluid pressure control device to which the present embodiment is applied. As shown in the figure, wheel cylinders 21, 22, 23, and 24 are mounted on the front right wheel FR, the front left wheel FL, the rear right wheel RR, and the rear left wheel RL, respectively. . Wheel cylinders 21 for wheels FR and RL
4 is connected to one pressure chamber (not shown) of the tandem-type master cylinder 11 via a first hydraulic pipe P1,
Wheel cylinders 22 and 23 for wheels FL and RR
A so-called X pipe (diagonal pipe) is connected to the other pressure chamber (not shown) of the master cylinder 11 via a second hydraulic pipe P2 which is liquid-tightly separated from the first hydraulic pipe P1. Is composed. The front wheels FR and FL are driving wheels, and the rear wheels RL and RR are driven wheels, but the driving method in the present invention is not limited to this.

The master cylinder 11 is connected to a brake pedal 14 via a vacuum booster 12 and is connected to a master reservoir 13. In response to the operation of the brake pedal 14, the master cylinder 11 is boosted via the vacuum booster 12, and the brake fluid in the master reservoir 13 is boosted to increase the pressure of the first and second hydraulic pressure pipes P1, P
2, the master cylinder hydraulic pressure is output.

The first hydraulic pipe P1 has two normally open two-port two-position solenoid valves 33a and 34a and two normally closed two-port two-pole solenoid valves 33b and 34.
b, an auxiliary reservoir 32a, a hydraulic pump 31a, and the like. The on-off valves 33a and 34a are disposed between the wheel cylinders 21 and 24 and the master cylinder 11, respectively, and the on-off valves 33b and 34b are disposed between the wheel cylinders 21 and 24 and the auxiliary reservoir 32a, respectively. The auxiliary reservoir 32a is provided independently of the master reservoir 13, and can be called an accumulator.
It has a piston and a spring, and is configured to be able to store a predetermined volume of brake fluid. Hydraulic pump 31a
Has a suction side connected to the auxiliary reservoir 32a, and a discharge side connected to the on-off valves 33a, 34a and the master cylinder 11a.
Connected between them. The hydraulic pump 31a is driven by an electric motor 37, sucks the brake fluid in the auxiliary reservoir 32a, and discharges the brake fluid between the on-off valves 33a and 34a and the master cylinder 11.

On the other hand, similarly, the second hydraulic pipe P2
Normally open two-port two-position solenoid on-off valves 35a and 35
6a, two normally closed 2-port 2-position solenoid valve 35
b and 36b, auxiliary reservoir 32b, hydraulic pump 31b
And so on. The on-off valves 35a and 36a are respectively connected to the wheel cylinders 22 and 23 and the master cylinder 1
The on-off valves 35b and 36b are disposed between the wheel cylinders 22 and 23 and the auxiliary reservoir 32b, respectively. The auxiliary reservoir 32b is also provided independently of the master reservoir 13, and is configured to be able to store a predetermined volume of brake fluid. Hydraulic pump 31b
Has a suction side connected to the auxiliary reservoir 32b and a discharge side connected to the on-off valves 35a and 36a and the master cylinder 11b.
Connected between them. The hydraulic pump 31b is also driven by the electric motor 37.

The above-mentioned on-off valves 33a-36a, 33b-3
Numeral 6b is to individually reduce (pulse pressure reduction), hold, and increase (pulse pressure increase) the brake fluid pressure of each of the wheel cylinders 21 to 24 by adjusting the time interval of energization / de-energization. Functions as a hydraulic control valve.

Wheel speed sensors 41, 42, 43, and 44 are provided on the wheels FR, FL, RR, and RL, respectively.
These are connected to the electronic control unit 40, and the rotation speed of each wheel, that is, a pulse signal having a pulse number proportional to the wheel speed is input to the electronic control unit 40.

A stop switch 45, which is turned on when the brake pedal 14 is depressed, and an acceleration sensor 46 for detecting the acceleration of the vehicle are connected to the electronic control unit 40. 40 is input.

The electronic control unit 40 includes a CPU 47b, a ROM 47c, and a RAM interconnected via a bus 47a.
47d, timer 47e, input interface circuit 47
and a microcomputer 47 including an output interface circuit 47g and the like. Output signals from the wheel speed sensors 41 to 44, the stop switch 45, and the acceleration sensor 46 are sent from the input interface circuit 47f to the CPU 4 via amplifier circuits 48a to 48f, respectively.
7b. Also, the output interface circuit 47g outputs drive circuits 49a-49.
Control signals are output to the electric motor 37 and the electromagnetic on-off valves (hydraulic pressure control valves) 33a to 36a and 33b to 36b via i.

In the microcomputer 47, the CP
The U 47b executes various arithmetic processes according to a control program and initial data stored in the ROM 47c in advance. In addition, the RAM 47d temporarily stores the calculation result and the like by the CPU 47b.

The electric motor 37 and the electromagnetic on-off valves (hydraulic pressure control valves) 33a to 36a and 33b to 36b are driven and controlled by the electronic control unit 40, and are provided with anti-skid control, braking force distribution control, and braking force distribution described later. Backup control is performed. The anti-skid control controls the braking force applied to each wheel so as to prevent the wheel from being locked when the brake pedal is operated. The braking force distribution control adjusts the braking force of the rear wheels to a predetermined relationship with the braking force of the front wheels when operating the brake pedal. To prevent.

Next, the manner of controlling the braking force in the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing a main routine for controlling the braking force, and this processing is executed by a periodic interruption every predetermined time (for example, 6 ms [millisecond]).

When the process proceeds to this routine, first, in step 101, the CPU 47b reads the detection signals of the wheel speed sensors 41 to 44, the stop switch 45, and the acceleration sensor 46, and proceeds to step 102.

In step 102, the CPU 47b
Wheel speeds VwFR, VwFL, VwRR, VwRL of each wheel based on the detection signals of the wheel speed sensors 41 to 44.
Is calculated, and the routine goes to step 103.

In step 103, the CPU 47b
Wheel speed VwFR, VwFL, VwRR, Vw of each wheel
RL is differentiated, and the wheel acceleration DVwFR, DVw of each wheel is obtained.
Calculate FL, DVwRR, DVwRL.

Next, the CPU 47b proceeds to step 104, where the wheel speeds VwFR, VwFL, VwRR,
An estimated vehicle speed Vso at the position of the center of gravity of the vehicle is calculated based on VwRL, and the estimated vehicle speed Vso is differentiated to calculate the vehicle acceleration DV in the front-rear direction at the position of the center of gravity of the vehicle
Calculate so. Note that, instead of the calculated value of the vehicle body acceleration DVso, for example, a longitudinal acceleration sensor may be separately provided and its detection signal may be used.

Next, the CPU 47b proceeds to step 105, calculates the actual vehicle acceleration DVr based on the detection signal of the acceleration sensor 46, and proceeds to step 106.
In step 106, the CPU 47b determines whether or not the anti-skid control start condition is satisfied. Here, when it is determined that the anti-skid control start condition is satisfied, the CPU 47b proceeds to step 107, executes the anti-skid control based on a control routine described later, and temporarily ends the subsequent processing.

On the other hand, if it is determined in step 106 that the anti-skid control start condition is not satisfied, C
The PU 47b proceeds to Step 108 to determine whether or not the braking force distribution control start condition is satisfied. here,
When it is determined that the braking force distribution control start condition is not satisfied, the CPU 47b temporarily ends the subsequent processing. Therefore, in this case, the operation is shifted to the normal brake.

On the other hand, if it is determined in step 108 that the braking force distribution control start condition is satisfied, the CPU 4
7b, proceeding to step 109, the wheel speed sensors 41 to 44, the stop switch 45, and the acceleration sensor 4
6 is determined to be in an abnormal state. The abnormal states of the wheel speed sensors 41 to 44, the stop switch 45, and the acceleration sensor 46 are each detected by a known method and used for the determination by the CPU 47b.

In step 109, the wheel speed sensor 4
1-4, a stop switch 45 and an acceleration sensor 46
Is determined to be in a normal state, the CPU 47b
Moves to step 110, executes the braking force distribution control based on a control routine described later, and temporarily ends the subsequent processing.

On the other hand, if it is determined in step 109 that any of the wheel speed sensors 41 to 44, the stop switch 45, and the acceleration sensor 46 is in an abnormal state, C
The PU 47b proceeds to step 111, executes the braking force distribution backup control based on a control routine described later, and temporarily ends the subsequent processing.

Next, a processing routine for the anti-skid control will be described with reference to FIGS. When the process proceeds to this routine, first, in step 201, the CPU 47b sets the control flag XABS to “1”.
It is determined whether or not is set. The control-in-progress flag XABS is set to “1” when the anti-skid control is being performed, and is used for determining that the anti-skid control is being performed.

Here, if it is determined that the control-in-progress flag XABS is set to "0", it is determined that the anti-skid control is not being performed, and the CPU 47b proceeds to step 202 to satisfy the anti-skid control start condition. It is determined whether or not. Then, when it is determined that the start condition of the anti-skid control is not satisfied, the CPU 47b returns to the main flow of FIG. 3 and temporarily ends the subsequent processing.

On the other hand, if it is determined in step 202 that the start condition of the anti-skid control is satisfied, the CP
U47b proceeds to step 203 and executes the control flag X
ABS is set to "1", and then the process proceeds to step 204, where the first speed threshold VSN and the second speed threshold VSH are calculated based on the estimated vehicle speed Vso. In addition,
The first and second speed thresholds VSN and VSH are calculated to the values shown in FIG. 5 with respect to the estimated vehicle speed Vso, and the first speed threshold VSN is the second speed threshold VSH. It is set to a larger value. Each of the speed thresholds VSN and VSH is set to a larger value when the stop switch 45 is on than when it is off. These speed thresholds VSN and VSH are used for setting a control hydraulic mode described later.

First and second speed thresholds VSN, VSH
The CPU 47b that has calculated the first acceleration threshold G1 based on the actual vehicle acceleration DVr proceeds to step 205.
And a second acceleration threshold G2. The first acceleration threshold G1 is calculated with respect to the actual vehicle acceleration DVr in accordance with the map shown in FIG. Incidentally, the second acceleration threshold value G2 also shown in the figure is a constant (= 0) and is set to a value larger than the first acceleration threshold value G1. These acceleration threshold values G1 and G2 are used for setting a control hydraulic pressure mode described later.

Next, the CPU 47b proceeds to step 206, and in steps 102 and 103, each wheel F
Wheel speed Vw * calculated for each of R, FL, RR, RL
* And wheel acceleration DVw ** (where ** corresponds to FR, FL, RR, RL, respectively), the first and second speed thresholds VSN, VSH and the first and second acceleration, respectively. The control hydraulic pressure mode is set in accordance with an area divided as shown in FIG. 7 by the threshold values G1 and G2. That is, the CPU 47b calculates the wheel speed Vw * of each wheel **
* Is compared with the first and second speed thresholds VSN and VSH, and the wheel acceleration DVw ** is compared with the first and second acceleration thresholds G1 and G2. And the CPU 47
b sets the control hydraulic mode in accordance with the result of comparison with these. For example, the wheel speed Vw ** of the wheel ** is greater than the first speed threshold value VSN, and the wheel acceleration DV
When w ** is larger than the second acceleration threshold value G2, the mode of pulse pressure increase is set.

The setting of the control hydraulic mode is for performing a suitable anti-skid control in accordance with the wheel speed Vw ** and the wheel acceleration DVw ** of the vehicle.
Incidentally, the braking force is applied by setting the pulse pressure increase, and the braking force is relaxed by setting the pressure reduction (pulse pressure reduction).

CPU 47b with control hydraulic mode set
Moves to step 207 to determine whether or not the vehicle is in the rear row select state. This rear low select controls the braking force of both rear wheels RR and RL based on the rotation speed of the rear wheel having the lower rotation speed (wheel speed). Specifically, the rear low select includes the right rear wheel RR and the left rear wheel RR. When the control hydraulic pressure modes of the wheels RL are different from each other, the control hydraulic pressure mode of the remaining rear wheels is set in accordance with the rear wheel set as the control hydraulic pressure mode on the side that further reduces the braking force. Here, when it is determined that the state is the rear low select state, the CPU 47b proceeds to step 208 and determines whether or not the rear wheel is selected as the right rear wheel RR. If the right rear wheel RR has been selected, the CPU 47b proceeds to step 209 to shift to the left rear wheel R.
The control hydraulic mode of L is set in accordance with the control hydraulic mode of the right rear wheel RR. If the right rear wheel RR is not selected (the left rear wheel RL is selected), the CPU 47b proceeds to step 210. Then, the control hydraulic pressure mode of the right rear wheel RR is set in accordance with the control hydraulic pressure mode of the left rear wheel RL. Then, the CPU 47b returns to the main flow of FIG. 3 and temporarily ends the subsequent processing.

On the other hand, if it is determined in step 207 that the vehicle is not in the rear low select state, the CPU 47b
Returning to the main flow of FIG. 3 in the state of the set control hydraulic pressure mode, the subsequent processing is temporarily ended.

When it is determined in step 201 that the control-in-progress flag XABS is set to "1", the CPU 47b determines that anti-skid control is being performed and proceeds to step 211 to satisfy the anti-skid control end condition. It is determined whether or not. Here, if it is determined that the termination condition of the anti-skid control is not satisfied, the CPU
47b performs the processing of the above steps 203 to 210,
The control hydraulic pressure mode is set according to the state, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing.

On the other hand, if it is determined in step 211 that the end condition of the anti-skid control is satisfied, the CP
U47b proceeds to step 212, and the control flag X
The ABS is set to “0” to end the anti-skid control, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing.

The CPU 47b operates the electromagnetic on-off valves (hydraulic pressure control valves) 33a-36a, 33b-36b and the electric motor 3 in accordance with the control hydraulic mode set in this manner.
7 to control the braking force of each of the wheels FR, FL, RR, RL appropriately.

Next, a processing routine for the braking force distribution control will be described with reference to FIGS. When the process proceeds to this routine, first, in step 301, the CPU 47b sets various constants.
Move to

In step 302, the CPU 47b
Based on wheel speeds VwFR, VwFL, VwRR, VwRL, reference speeds VwsFR, VwsFL, Vw, respectively.
Calculate sRR and VwsRL. Specifically, the right front wheel F
Taking R as an example, a value obtained by adding a predetermined value αup · t to the wheel speed VwFR (n) of the right front wheel FR in the current calculation cycle and the wheel speed VwFR (n-11) of the right front wheel FR in the previous calculation cycle. And a predetermined value αdn · t between the wheel speed VwFR (n−1) of the previous wheel FR and the lower value of
Is set as the reference speed VwsFR of the right front wheel FR.

Here, the value αup represents the upper limit of the rate of increase of the wheel acceleration, that is, the wheel speed, and is set to, for example, 2G. The value t is a calculation cycle, and the value αdn represents a wheel deceleration, that is, an upper limit value of a reduction rate of the wheel speed.
Set to 5G. By calculating the reference speed in this manner, an accurate reference speed can be calculated even when an accurate wheel speed cannot be obtained due to the influence of road surface disturbance such as a bad road or a step.

Subsequently, the CPU 47b proceeds to step 303, where the reference speeds VwsFR, VwsFL, Vws of the wheels are set.
Differentiate RR and VwsRL, respectively, and calculate the wheel reference acceleration D
VwsFR, DVwsFL, DVwsRR, DVwsR
Calculate L.

Next, the CPU 47b proceeds to step 304 and executes a braking force distribution control calculation process on the rear wheels RR and RL. That is, as shown in FIG. 9, a processing routine for the braking force distribution control calculation is performed.
In CPU, the CPU 47b determines whether or not the control flag XEBD is set to “1”. The control-in-progress flag XEBD is set to “1” when the braking force distribution control is being performed, and is used for determining that the braking force distribution control is being performed.

If it is determined that the control flag XEBD is set to "0", the CPU 47b proceeds to step 312 assuming that the braking force distribution control is not being performed, and sets the start condition of the braking force distribution control. It is determined whether or not the condition is satisfied. The start condition is, for example, the vehicle acceleration D
The magnitude of the change amount of Vso tends to be abrupt braking exceeding a predetermined value. When it is determined that the start condition of the braking force distribution control is not satisfied, the CPU 47b
Returns to the main flow of FIG. 3 and terminates the subsequent processing once.

On the other hand, if it is determined in step 312 that the conditions for starting the braking force distribution control are satisfied, the CPU 4
7b, the process proceeds to step 313 and the control flag XEB is set.
D is set to "1", and then the routine proceeds to step 314, where the first speed threshold value VW is set based on the estimated vehicle speed Vso.
S1 and a second speed threshold value VWS2 are calculated. In addition,
These first and second speed thresholds VWS1, VWS2
Is calculated to the value shown in FIG. 10 with respect to the estimated vehicle speed Vso, and the first speed threshold value VWS1 is set to a value larger than the second speed threshold value VWS2.
Each of the speed thresholds VWS1 and VWS2 is set to a larger value when the stop switch 45 is on than when it is off. These speed thresholds VWS1 and VWS2 are used for setting a control hydraulic mode described later.

First and second speed thresholds VWS1, VW
The CPU 47b having calculated S2 proceeds to step 315, and calculates the first acceleration threshold GS1 and the second acceleration threshold GS2 based on the actual vehicle acceleration DVr.
The first acceleration threshold GS1 is equal to the actual vehicle acceleration D
Vr is calculated according to the map shown in FIG. Incidentally, the second acceleration threshold value GS2 also shown in the figure is a constant (= 0) and is set to a value larger than the first acceleration threshold value GS1. These acceleration threshold values GS1 and GS2 are used for setting a control hydraulic mode described later.

Next, the CPU 47b proceeds to step 316, in which the wheel reference speed VwsR * and the wheel reference acceleration DVwsR * calculated for each rear wheel RR, RL (where * corresponds to R, L, respectively). On the other hand, the control hydraulic pressure mode is set in accordance with the areas divided as shown in FIG. 12 by the first and second speed thresholds VWS1, VWS2 and the first and second acceleration thresholds GS1, GS2, respectively. . That is, the CPU 47b compares the wheel reference speed VwsR * of each rear wheel R * with the first and second speed thresholds VWS.
1, VWS2, and the wheel reference acceleration DV.
wsR * is set to the first and second acceleration threshold values GS1 and GS2.
Compare with Then, the CPU 47b sets the control hydraulic pressure mode according to the result of comparison with these. For example, the wheel reference speed VwsR * of the rear wheel R * is equal to the first speed threshold VW.
Greater than S1 and wheel reference acceleration DVwsR *
Is larger than the second acceleration threshold value GS2, the mode of pulse pressure increase is set.

The control hydraulic pressure mode is set according to the reference wheel speed VwsR * and the reference wheel acceleration DVws.
This is for performing suitable braking force distribution control corresponding to R *. Incidentally, the braking force is applied by setting the pulse pressure increase, and the braking force is relaxed by setting the pulse pressure reduction.

CPU 47b with control hydraulic mode set
Goes to step 317 to determine whether or not the vehicle is in the rear low select state. Here, when it is determined that the state is the rear low select, the CPU 47b proceeds to step 318 and determines whether or not the rear wheel is selected as the right rear wheel RR. And when the right rear wheel RR is selected,
The CPU 47b proceeds to step 319 to set the control hydraulic pressure mode of the left rear wheel RL in accordance with the control hydraulic pressure mode of the right rear wheel RR, and the right rear wheel RR is not selected (the left rear wheel RL).
Is selected), the CPU 47b proceeds to step 320 and sets the control hydraulic pressure mode of the right rear wheel RR in accordance with the control hydraulic pressure mode of the left rear wheel RL. And C
The PU 47b returns to the main flow of FIG. 3 and temporarily ends the subsequent processing.

On the other hand, if it is determined in step 317 that the state is not the rear low select state, the CPU 47b
Returning to the main flow of FIG. 3 in the state of the set control hydraulic pressure mode, the subsequent processing is temporarily ended.

If it is determined in step 311 that the control-in-progress flag XEBD is set to "1", the CPU 47b determines that the braking force distribution control is being performed and proceeds to step 311.
The process proceeds to 21 to determine whether or not the termination condition of the braking force distribution control is satisfied. As the termination condition, for example, the vehicle body acceleration DVso may exceed a predetermined value (for example, -0.25 G). Here, when it is determined that the end condition of the braking force distribution control is not satisfied, the CPU 47b performs the processing of the above steps 313 to 320, sets the control hydraulic pressure mode according to the state, and sets the main flow of FIG. To temporarily end the subsequent processing.

On the other hand, if it is determined in step 321 that the termination condition of the braking force distribution control is satisfied, the CPU 4
7b, the process proceeds to step 322 and the control flag XEB is set.
D is set to "0" to terminate the braking force distribution control, return to the main flow of FIG. 3, and temporarily end the subsequent processing.

The CPU 47b operates the electromagnetic on-off valves (hydraulic pressure control valves) 33a-36a, 33b-36b and the electric motor 3 in accordance with the control hydraulic mode set in this manner.
7 to control the rear wheels RR, FL with respect to the front wheels FR, FL.
The RL braking force distribution is appropriately controlled.

Next, a processing routine for the braking force distribution backup control will be described with reference to FIG. The backup control of the braking force distribution in the present embodiment is performed by applying the anti-skid control mode mutatis mutandis.

When the processing shifts to this routine, first, in step 401, the CPU 47b
It is determined whether 6 is normal. Here, the acceleration sensor 46
Is determined to be abnormal, the CPU 47b proceeds to step 4
02, and the actual vehicle acceleration D corresponding to the detection signal
Vr is set to a default value of -1G, and step 4
Move to 05. The actual vehicle acceleration DVr is set in this way by setting the first acceleration threshold value G1 used for selecting the area of the control hydraulic mode in the anti-skid control to the minimum value, as shown in FIG. This is because the control hydraulic pressure mode for the wheel acceleration DVw ** in FIG. 7 is corrected so that more braking force is applied.

On the other hand, if it is determined in step 401 that the acceleration sensor 46 is normal, the CPU 47b proceeds to step 403 and determines whether the stop switch 45 is normal. Here, if it is determined that the stop switch 45 is abnormal, the CPU 47b proceeds to step 404, sets that the stop switch 45 is off,
Move to step 405. Setting the state of the stop switch 45 in this manner is as shown in FIG.
In the anti-skid control, the first and second speed thresholds VSN and VSH used for selecting the control hydraulic mode region are set to smaller values, and the wheel speed Vw ** in FIG.
This is to correct the control hydraulic pressure mode to apply more braking force.

In step 405, the CPU 47b
It is determined whether the wheel speed sensors 41 and 42 of the front wheels FR and FL are abnormal. Here, if it is determined that none of the wheel speed sensors 41, 42 of the front wheels FR, FL is abnormal (all are normal), the CPU 47b proceeds to step 4
06, the wheel speed sensors 43 of the rear wheels RR, RL,
It is determined whether 44 is abnormal.

Then, none of the wheel speed sensors 43, 44 of the rear wheels RR, RL are abnormal (all are normal).
When the determination is made, the CPU 47b proceeds to step 415 to control the control hydraulic pressure of the rear wheels (ie, both rear wheels RR and RL) having the normal wheel speed sensors 43 and 44 in accordance with the anti-skid control. The mode is set, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing.

In step 406, the rear wheels RR,
When it is determined that one of the RL wheel speed sensors 43 and 44 is abnormal, the CPU 47b proceeds to step 409.
To step 4 to set the rear low select control.
Move to 15. Then, in step 415, the control hydraulic pressure mode is set for the rear wheel RR or RL having one normal wheel speed sensor 43 or 44 in accordance with the anti-skid control, and the control hydraulic pressure mode is adjusted to this control hydraulic pressure mode. And the remaining rear wheels (rear wheels with abnormal wheel speed sensors 43 or 44) RR or R
The control hydraulic pressure mode of L is set, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing.

Further, at step 406, the rear wheel R
If it is determined that all of the R and RL wheel speed sensors 43 and 44 are abnormal, the CPU 47b proceeds to step 410 and prohibits the setting of the control hydraulic pressure mode according to the anti-skid control for the rear wheels RR and RL. Then, the process returns to the main flow of FIG. 3 and the subsequent processing is temporarily terminated. Therefore, in this case, the operation is shifted to the normal brake.

In step 405, the front wheels FR,
If it is determined that one of the wheel speed sensors 41 and 42 of the FL is abnormal, the CPU 47b proceeds to step 407.
And the wheel speed sensors 43, 44 of the rear wheels RR, RL
It is determined whether or not is abnormal.

Then, none of the wheel speed sensors 43 and 44 of the rear wheels RR and RL are abnormal (all are normal).
When the determination is made, the CPU 47b proceeds to step 415 to control the control hydraulic pressure of the rear wheels (ie, both rear wheels RR and RL) having the normal wheel speed sensors 43 and 44 in accordance with the anti-skid control. The mode is set, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing.

In step 407, the rear wheels RR,
If it is determined that one of the RL wheel speed sensors 43 and 44 is abnormal, the CPU 47b proceeds to step 411.
To step 4 to set the rear low select control.
Move to 15. Then, the process proceeds to step 415 to set the control hydraulic pressure mode according to the anti-skid control for the rear wheel RR or RL having the normal one wheel speed sensor 43 or 44, and to set the control hydraulic pressure The control hydraulic pressure mode of the remaining rear wheels RR or RL (the rear wheels having abnormal wheel speed sensors 43 or 44) is set in accordance with the mode, and the process returns to the main flow of FIG. I do.

Further, at step 407, the rear wheel R
When it is determined that all of the R and RL wheel speed sensors 43 and 44 are abnormal, the CPU 47b proceeds to step 412 and prohibits the setting of the control hydraulic pressure mode according to the anti-skid control for the rear wheels RR and RL. Then, the process returns to the main flow of FIG. 3 and the subsequent processing is temporarily terminated. Therefore, in this case, the operation is shifted to the normal brake.

In step 405, the front wheels FR,
When it is determined that all of the wheel speed sensors 41 and 42 of the FL are abnormal, the CPU 47b proceeds to step 408 and determines whether or not the wheel speed sensors 43 and 44 of the rear wheels RR and RL are abnormal.

Then, none of the wheel speed sensors 43 and 44 of the rear wheels RR and RL are abnormal (all are normal).
When the determination is made, the CPU 47b proceeds to step 415 to control the control hydraulic pressure of the rear wheels (ie, both rear wheels RR and RL) having the normal wheel speed sensors 43 and 44 in accordance with the anti-skid control. The mode is set, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing.

At step 408, the rear wheels RR,
If it is determined that one of the RL wheel speed sensors 43 and 44 is abnormal, the CPU 47b proceeds to step 413.
To step 4 to set the rear low select control.
Move to 15. Then, the process proceeds to step 415 to set the control hydraulic pressure mode according to the anti-skid control for the rear wheel RR or RL having the normal one wheel speed sensor 43 or 44, and to set the control hydraulic pressure The control hydraulic pressure mode of the remaining rear wheels RR or RL (the rear wheels having abnormal wheel speed sensors 43 or 44) is set in accordance with the mode, and the process returns to the main flow of FIG. I do.

Further, at step 408, the rear wheel R
When it is determined that all of the R and RL wheel speed sensors 43 and 44 are abnormal, the CPU 47b proceeds to step 414 and prohibits the setting of the control hydraulic pressure mode according to the anti-skid control for the rear wheels RR and RL. Then, the process returns to the main flow of FIG. 3 and the subsequent processing is temporarily terminated. Therefore, in this case, the operation is shifted to the normal brake.

The CPU 47b operates the electromagnetic on-off valves (hydraulic pressure control valves) 33a-36a, 33b-36b and the electric motor 3 in accordance with the control hydraulic mode set in this manner.
7 to control the braking force of each rear wheel RR, RL appropriately.

As described in detail above, according to the present embodiment, the following effects can be obtained. (1) In this embodiment, even if any of the wheel speed sensors 41 to 44, the stop switch 45, and the acceleration sensor 46 is abnormal, at least the wheel speed sensors 43 and 44 of both the rear wheels RR and RL are both set. Unless abnormal, the control hydraulic pressure mode is set according to the anti-skid control, and the braking force distribution control is continued. Therefore, in such a case, the stability of the vehicle, particularly in the high-G region, can be ensured as compared with, for example, the control in which the braking force distribution control is prohibited.

(2) In the present embodiment, the existing anti-skid control is applied mutatis mutandis as backup control of the braking force distribution, so that an increase in the calculation load of the microcomputer 47 can be suppressed to a minimum.

(3) In this embodiment, when an abnormality is detected in the stop switch 45 or the acceleration sensor 46, the detected value or the like is set to a value on the side to which more braking force is applied. Therefore, it is possible to prevent a braking force shortage in the backup control.

(Second Embodiment) Hereinafter, a second embodiment of the braking force distribution control device embodying the present invention will be described with reference to FIG. The second embodiment differs from the first embodiment only in that the backup control of the braking force distribution is executed by applying the mode of the braking force distribution control instead of the anti-skid control. Detailed description of the parts will be omitted.

FIG. 14 shows a processing routine of the braking force distribution backup control in step 111 of FIG. When the process proceeds to this routine, first, in step 500, the CPU 47b performs constant setting and the like in the same manner as in steps 301 to 303, and proceeds to step 501.

In step 501, the CPU 47b
It is determined whether or not the acceleration sensor 46 is normal. If it is determined that the acceleration sensor 46 is abnormal, the CPU 47
In step b, the process proceeds to step 502, where the actual vehicle acceleration DVr corresponding to the detection signal is set to a default value of -1G, and the process proceeds to step 505. As shown in FIG. 11, the actual vehicle body acceleration DVr is set by setting the first acceleration threshold GS1 used for selecting the area of the control hydraulic mode in the braking force distribution control to the minimum value. , FIG.
This is because the control hydraulic pressure mode for the wheel reference acceleration DVwsR * is corrected so that the braking force is applied more in Step 2.

On the other hand, if it is determined in step 501 that the acceleration sensor 46 is normal, the CPU 47b proceeds to step 503 to determine whether the stop switch 45 is normal. Here, if it is determined that the stop switch 45 is abnormal, the CPU 47b proceeds to step 504, sets that the stop switch 45 is off,
Move to step 505. As shown in FIG. 10, the state of the stop switch 45 is set in the first and second speed thresholds VWS1, VWS2 used for selecting the region of the control hydraulic pressure mode in the brake distribution control.
Is set to a smaller value, and in FIG. 12, the control hydraulic pressure mode for the wheel reference speed VwsR * is corrected so as to apply more braking force.

At the step 505, the CPU 47b
It is determined whether the wheel speed sensors 41 and 42 of the front wheels FR and FL are abnormal. Here, if it is determined that none of the wheel speed sensors 41, 42 of the front wheels FR, FL is abnormal (all are normal), the CPU 47b proceeds to step 5
06, the wheel speed sensors 43 of the rear wheels RR, RL,
It is determined whether 44 is abnormal.

Then, none of the wheel speed sensors 43, 44 of the rear wheels RR, RL are abnormal (all are normal).
When the determination is made, the CPU 47b proceeds to step 515 to control the control fluid for the rear wheels (that is, both rear wheels RR and RL) having the normal wheel speed sensors 43 and 44 in accordance with the braking force distribution control. The pressure mode is set, and the process returns to the main flow in FIG. 3 to temporarily end the subsequent processing.

In step 506, the rear wheels RR,
If it is determined that one of the RL wheel speed sensors 43 and 44 is abnormal, the CPU 47b proceeds to step 509.
To step 5 to set the rear low select control.
Move to 15. Then, in step 515, the control hydraulic pressure mode is set for the rear wheel RR or RL having one normal wheel speed sensor 43 or 44 in accordance with the braking force distribution control, and the control hydraulic pressure mode is set to this control hydraulic pressure mode. At the same time, the control hydraulic pressure mode of the remaining rear wheel (the rear wheel having the abnormal wheel speed sensor 43 or 44) RR or RL is set, and the process returns to the main flow of FIG.

Further, at step 506, the rear wheel R
When it is determined that all of the R and RL wheel speed sensors 43 and 44 are abnormal, the CPU 47b proceeds to step 510 and sets the control hydraulic pressure mode according to the braking force distribution control for the rear wheels RR and RL. The process is prohibited, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing. Therefore,
In this case, the operation is shifted to the normal brake.

In step 505, the front wheels FR,
If it is determined that one of the wheel speed sensors 41 and 42 of the FL is abnormal, the CPU 47b proceeds to step 507.
And the wheel speed sensors 43, 44 of the rear wheels RR, RL
It is determined whether or not is abnormal.

Then, none of the wheel speed sensors 43, 44 of the rear wheels RR, RL are abnormal (all are normal).
When the determination is made, the CPU 47b proceeds to step 515 to control the control fluid for the rear wheels (that is, both rear wheels RR and RL) having the normal wheel speed sensors 43 and 44 in accordance with the braking force distribution control. The pressure mode is set, and the process returns to the main flow in FIG. 3 to temporarily end the subsequent processing.

In step 507, the rear wheels RR,
When it is determined that one of the RL wheel speed sensors 43 and 44 is abnormal, the CPU 47b proceeds to step 511.
To step 5 to set the rear low select control.
Move to 15. Then, the process proceeds to step 515 to set the control hydraulic mode of the rear wheel RR or RL having one normal wheel speed sensor 43 or 44 in accordance with the anti-skid control, and to set the control hydraulic pressure mode. The control hydraulic pressure mode of the remaining rear wheels RR or RL (the rear wheels having abnormal wheel speed sensors 43 or 44) is set in accordance with the mode, and the process returns to the main flow of FIG. I do.

Further, at step 507, the rear wheel R
When it is determined that all of the R and RL wheel speed sensors 43 and 44 are abnormal, the CPU 47b proceeds to step 512 and sets the control hydraulic pressure mode according to the braking force distribution control for the rear wheels RR and RL. The process is prohibited, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing. Therefore,
In this case, the operation is shifted to the normal brake.

In step 505, the front wheels FR,
When it is determined that all of the wheel speed sensors 41 and 42 of the FL are abnormal, the CPU 47b proceeds to step 508 and determines whether or not the wheel speed sensors 43 and 44 of the rear wheels RR and RL are abnormal.

Then, none of the wheel speed sensors 43, 44 of the rear wheels RR, RL are abnormal (all are normal).
When the determination is made, the CPU 47b proceeds to step 515 to control the control fluid for the rear wheels (that is, both rear wheels RR and RL) having the normal wheel speed sensors 43 and 44 in accordance with the braking force distribution control. The pressure mode is set, and the process returns to the main flow in FIG. 3 to temporarily end the subsequent processing.

In step 508, the rear wheels RR,
If it is determined that one of the RL wheel speed sensors 43 and 44 is abnormal, the CPU 47b proceeds to step 513.
To step 5 to set the rear low select control.
Move to 15. Then, in step 515, the control hydraulic pressure mode is set for the rear wheel RR or RL having one normal wheel speed sensor 43 or 44 in accordance with the braking force distribution control, and the control hydraulic pressure mode is set to this control hydraulic pressure mode. At the same time, the control hydraulic pressure mode of the remaining rear wheel (the rear wheel having the abnormal wheel speed sensor 43 or 44) RR or RL is set, and the process returns to the main flow of FIG.

Further, at step 508, the rear wheel R
If it is determined that all of the R and RL wheel speed sensors 43 and 44 are abnormal, the CPU 47b proceeds to step 514 to set the control hydraulic pressure mode according to the braking force distribution control for the rear wheels RR and RL. The process is prohibited, and the process returns to the main flow of FIG. 3 to temporarily end the subsequent processing. Therefore,
In this case, the operation is shifted to the normal brake.

The CPU 47b operates the electromagnetic on-off valves (hydraulic pressure control valves) 33a-36a, 33b-36b and the electric motor 3 in accordance with the control hydraulic mode set in this manner.
7 to control the braking force of each rear wheel RR, RL appropriately.

As described in detail above, according to the present embodiment, the same effects as those of the first embodiment can be obtained. Note that the embodiment of the present invention is not limited to the above-described embodiment, and may be modified as follows.

In each of the above embodiments, the brake pipe is constituted by the X pipe, but may be constituted by the Y pipe. In the above embodiments, the control hydraulic pressure mode of the anti-skid control or the braking force distribution control is set by the first acceleration threshold G1 or GS1 calculated based on the detection signal of the acceleration sensor 46 provided in the vehicle. However, the control hydraulic mode may be set without providing the acceleration sensor as described above.

[0101]

As described in detail above, according to the first aspect of the present invention, the braking force distribution control can be suitably performed even when an abnormality of a sensor or the like is detected.

According to the second aspect of the present invention, a very simple method of setting the detected value of the traveling state detecting means in which an abnormality has been detected to a predetermined value can be performed without increasing the calculation load of the microcomputer. Power distribution can be backed up.

According to the third and fifth aspects of the present invention, it is possible to prevent insufficient braking force in the backup control. According to the fourth aspect of the present invention, in the braking force distribution control device including the anti-skid control means, the anti-skid control is performed by setting the detection value of the traveling state detection means in which the abnormality is detected to a predetermined value. By a simple method, the braking force distribution can be backed up without increasing the calculation load of the microcomputer.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a brake fluid pressure control device to which a first embodiment of the present invention is applied.

FIG. 2 is an exemplary block diagram showing the electrical configuration of the embodiment.

FIG. 3 is a flowchart showing a braking force control procedure of the embodiment.

FIG. 4 is a flowchart showing an anti-skid control procedure of the embodiment.

FIG. 5 is a map showing a set value of a speed threshold value.

FIG. 6 is a map showing a relationship between actual vehicle acceleration and an acceleration threshold.

FIG. 7 is a map showing a relationship between a wheel speed and a wheel acceleration and a control hydraulic pressure mode.

FIG. 8 is a flowchart showing a braking force distribution control procedure of the embodiment.

FIG. 9 is a flowchart showing a braking force distribution control procedure of the embodiment.

FIG. 10 is a map showing set values of a speed threshold value.

FIG. 11 is a map showing a relationship between actual vehicle acceleration and an acceleration threshold.

FIG. 12 is a map showing a relationship between a wheel standard speed and a wheel standard acceleration and a control hydraulic mode.

FIG. 13 is a flowchart showing a braking force distribution backup control procedure of the embodiment.

FIG. 14 is a flowchart illustrating a braking force distribution backup control procedure according to the second embodiment of the present invention.

[Explanation of symbols]

 FR, FL, RR, RL Wheels 21 to 24 Wheel cylinders 33a to 36a, 33b to 36b Electromagnetic on-off valve 40 Electronic control unit 41 to 44 Wheel speed sensor 45 Stop switch 46 Acceleration sensor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenji Totsu 2-1-1 Asahi-cho, Kariya-shi, Aichi, Japan F-term (reference) 3D045 BB05 BB37 CC03 EE21 FF42 GG00 GG10 GG28 3D046 AA02 BB01 BB28 BB31 DD04 HH02 HH23 HH26 HH36 HH39 JJ04 JJ05 JJ07 KK02 KK07 LL23 LL50 MM06 MM13

Claims (5)

[Claims] 1. A braking force distribution control device comprising: a plurality of traveling state detecting means for detecting a traveling state of a vehicle; and performing a braking force distribution control in accordance with the detected traveling state. When one abnormality is detected, the braking force distribution control device performs backup control of the braking force distribution according to the traveling state detected by the remaining normal traveling state detecting means. 2. The braking force distribution control device according to claim 1, wherein the backup control is performed by setting a detection value of a traveling state detection unit in which the abnormality is detected to a predetermined value. Power distribution control device. 3. The braking force distribution control device according to claim 2, wherein the predetermined value set by the traveling state detecting means in which the abnormality is detected is a value on the side to which more braking force is applied. Braking force distribution control device. 4. The braking force distribution control device according to claim 1, further comprising: anti-skid control means for performing anti-skid control, wherein the backup control determines a detection value of the traveling state detection means in which the abnormality is detected. A braking force distribution control device, which is an anti-skid control performed by setting a value. 5. The braking force distribution control device according to claim 4, wherein the predetermined value set by the traveling state detecting means in which the abnormality is detected is a value on the side to which more braking force is applied. Braking force distribution control device.