JP5892023B2 - Braking force control device - Google Patents

Description

  The present invention relates to a braking force control device.

  Conventionally, techniques for detecting vehicle speed have been disclosed. For example, in Patent Document 1, in the high speed range where the average speed of the drive wheel is difficult to generate wheel spin, the average speed of the drive wheel is detected as the vehicle speed, and in the low speed range, the acceleration of each drive wheel is checked. In the low acceleration range where no wheel spin occurs, the average speed of the drive wheels is output as the vehicle speed, and if one of the drive wheels is not in the low acceleration range, the vehicle traveling speed of the third wheel from the highest is output. Techniques for speed detection devices are disclosed.

JP-A-11-304830

  There is still room for improvement in calculating vehicle speed. For example, if the vehicle speed detection error is large, the effect of braking force control may not be improved. In a braking force control apparatus, it is desired that a vehicle speed detection error can be suppressed.

  The objective of this invention is providing the braking force control apparatus which can suppress the detection error of a vehicle speed.

  The braking force control device of the present invention includes a control device that performs braking force control based on the vehicle speed calculated from the wheel speed, and the wheel speed of a predetermined driving wheel that is the driving wheel having the largest wheel speed is increasing, and When the wheel speeds of the three wheels other than the predetermined drive wheels tend to decrease, the vehicle speed is calculated excluding the wheel speeds of the predetermined drive wheels.

  The braking force control device of the present invention includes a control device that performs braking force control based on the vehicle speed calculated from the wheel speed, and the wheel speed of a predetermined driving wheel that is the driving wheel having the highest wheel speed and the wheel speed is the highest. When the difference from the wheel speed of the small wheel is equal to or greater than the depressurization threshold value of the ABS control, the vehicle speed is calculated excluding the wheel speed of the predetermined drive wheel.

  In the braking force control apparatus, when the vehicle speed is calculated excluding the wheel speed of the predetermined drive wheel, it is preferable to calculate the vehicle speed from the wheel speed of the rolling wheels.

  The braking force control device according to the present invention includes a control device that performs braking force control based on the vehicle speed calculated from the wheel speed, and the wheel speed of a predetermined driving wheel that is the driving wheel having the largest wheel speed tends to increase. In addition, when the wheel speeds of the three wheels other than the predetermined drive wheels tend to decrease, the vehicle speed is calculated excluding the wheel speeds of the predetermined drive wheels. According to the braking force control device of the present invention, there is an effect that the detection error of the vehicle speed can be suppressed.

FIG. 1 is a flowchart showing the operation of the braking force control apparatus according to the embodiment. FIG. 2 is a schematic configuration diagram of the vehicle according to the embodiment. FIG. 3 is an explanatory diagram of the driving wheel floating determination.

  Hereinafter, a braking force control device according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]
The embodiment will be described with reference to FIGS. 1 to 3. The present embodiment relates to a braking force control device. FIG. 1 is a flowchart showing the operation of a braking force control apparatus according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a vehicle according to the embodiment, and FIG. 3 is an explanatory diagram of driving wheel floating determination.

  As shown in FIG. 2, the vehicle 100 includes a drive source 5, a braking device 7, a wheel speed sensor 12, and an ECU 50. Further, the braking force control device 1-1 according to the present embodiment includes the ECU 50 and the braking device 7. The braking force control device 1-1 may further include a wheel speed sensor 12.

  The drive source 5 is a power source of the vehicle 100, and is, for example, an engine or a motor. The vehicle 100 travels by generating a driving force by the power transmitted from the driving source 5 to the wheels 3. The vehicle 100 has four wheels 3 (a left front wheel 3FL, a right front wheel 3FR, a left rear wheel 3RL, and a right rear wheel 3RR). The vehicle 100 of the present embodiment is a rear wheel drive vehicle, and the left rear wheel 3RL and the right rear wheel 3RR are drive wheels. The left front wheel 3FL and the right front wheel 3FR are rolling wheels (driven wheels).

  The braking device 7 is a braking device that generates a braking force on each wheel 3. The braking device 7 of the present embodiment generates a braking force by hydraulic pressure of a working fluid, for example, brake oil. The braking device 7 includes a brake pedal 6, a master cylinder 8, an actuator 9, a wheel cylinder 10, and a hydraulic braking unit 11.

  When the driver operates the brake pedal 6, the master cylinder 8 generates a master cylinder pressure corresponding to the pedal depression force (operation force) acting on the brake pedal 6. The braking device 7 operates the hydraulic braking unit 11 when the master cylinder pressure acts as the wheel cylinder pressure in the wheel cylinder 10 of each wheel 3. The hydraulic brake unit 11 includes a caliper, a brake pad, a disc rotor, and the like. The hydraulic brake unit 11 generates a braking force on the wheel 3 when the brake pad sandwiches and presses the disk rotor by the wheel cylinder pressure.

  Further, the braking device 7 can adjust the wheel cylinder pressure to be applied to the wheel cylinder 10 by the actuator 9. The actuator 9 has an oil pump, an oil reservoir, a control valve, and the like, and can independently control the wheel cylinder pressure supplied to the wheel cylinder 10 of each wheel 3.

  The ECU 50 is an electronic control unit having a computer. The ECU 50 has a function as a control device according to the braking force control device 1-1 of the present embodiment. The ECU 50 has a function of performing braking force control based on the vehicle speed calculated from the wheel speed (for example, the wheel speed of four wheels). The ECU 50 includes a processing unit 51, a storage unit 52, and an input / output unit 53. The processing unit 51 and the storage unit 52 are electrically connected to the accelerator pedal 4, the drive source 5, the brake pedal 6, the actuator 9, and the wheel speed sensor 12 via the input / output unit 53. Further, the processing unit 51 and the storage unit 52 can exchange information with each other.

  The ECU 50 acquires an operation amount for the accelerator pedal 4 such as an accelerator opening degree from an accelerator opening degree sensor provided in the accelerator pedal 4. In addition, the ECU 50 acquires information related to the operation state of the drive source 5. Further, the ECU 50 can obtain an operation amount for the brake pedal 6, for example, a pedal depression force, a pedal stroke, and a pedal operation speed, from a brake operation amount sensor provided in the brake pedal 6. Further, the ECU 50 can acquire the operating state of the actuator 9 and can instruct the actuator 9 on the wheel cylinder pressure to be applied to each wheel 3. The wheel speed sensor 12 detects the wheel speed of the wheel 3, and is disposed on each wheel 3. The ECU 50 acquires the wheel speed of each wheel 3 from the wheel speed sensor 12. The wheel speed is the ground speed of the wheel 3 and is the traveling speed of the vehicle 100 converted from the rotational speed of one wheel 3.

  The ECU 50 can operate the actuator 9 in any one of the pressure increasing mode, the holding mode, and the pressure reducing mode. The pressure increasing mode is a mode for increasing the wheel cylinder pressure. The holding mode is a mode for holding the wheel cylinder pressure. The decompression mode is a mode for reducing the wheel cylinder pressure. The actuator 9 can independently control the mode for each wheel 3.

  The ECU 50 can execute ABS control. ABS control is control which suppresses the lock | rock of the wheel 3 at the time of braking. The ECU 50 executes ABS control based on the wheel speed of each wheel 3. For example, the ECU 50 calculates the vehicle speed from the wheel speed of each wheel 3 and performs ABS control based on the speed difference between the vehicle speed and the wheel speed. The ECU 50 reduces the wheel cylinder pressure with respect to the wheel 3 in which the speed difference between the vehicle speed and the wheel speed, that is, the speed difference obtained by subtracting the wheel speed from the vehicle speed is equal to or greater than the pressure reduction threshold.

  The vehicle speed is, for example, the maximum value of the wheel speed of four wheels. Here, the left rear wheel 3RL and the right rear wheel 3RR, which are driving wheels, may slip due to floating, and the vehicle speed may be increased with respect to the actual speed. For example, in a vehicle having a large driving force in a creep state, the vehicle speed is likely to increase. If the vehicle speed increases, the other wheels 3 may be erroneously determined to be locked or locked, and the wheel cylinder pressure may be reduced.

  In the braking force control device 1-1 of the present embodiment, when the drive wheel slips, the drive wheel having the highest wheel speed (hereinafter referred to as “predetermined drive wheel”) among the drive wheels 3RL and 3RR. The vehicle speed is calculated excluding the wheel speed. Thereby, the vehicle speed can be calculated easily and accurately, or the vehicle speed can be calculated accurately in a short time. That is, the braking force control apparatus 1-1 according to the present embodiment can suppress an error of the vehicle speed with respect to the actual speed.

  The braking force control apparatus 1-1 of the present embodiment has two determination methods of driving wheel floating determination 1 and driving wheel floating determination 2 as slip determining methods due to driving wheel floating and the like. Thereby, it is possible to perform the floating determination easily in a short time.

(Driving wheel floating judgment 1)
The driving wheel floating determination 1 is a determination that the vehicle wheel speed is increased when the Max wheel speed of the driving wheel is increased from the previous value during braking and the wheel speeds of the remaining three wheels are in the downward direction from the previous value. That is, in the braking force control device 1-1, the wheel speed of the predetermined driving wheel that is the driving wheel having the highest wheel speed tends to increase, and the wheel speed of the three wheels 3 other than the predetermined driving wheel tends to decrease. In this case, the vehicle speed is calculated excluding the wheel speed of the predetermined drive wheel.

  For example, when the wheel speed of the left rear wheel 3RL is the maximum among the wheel speeds of four wheels, the wheel speed of the left rear wheel 3RL tends to increase and three wheels other than the left rear wheel 3RL (the left front wheel 3FL, the right When the wheel speeds of the front wheel 3FR and the right rear wheel 3RR are both decreasing, the vehicle speed is calculated excluding the wheel speed of the left rear wheel 3RL. In the present embodiment, the maximum value of the wheel speeds of the front wheels 3FL and 3FR that are rolling wheels among the remaining three wheels is set as the vehicle speed.

(Driving wheel float determination 2)
Drive wheel floating determination 2 determines that the vehicle speed has increased when the speed difference obtained by subtracting the minimum value of the wheel speeds of the remaining three wheels from the maximum value of the wheel speeds of the drive wheels is equal to or greater than the decompression threshold value of the ABS control. That is, in the braking force control device 1-1, the difference between the wheel speed of the predetermined driving wheel that is the driving wheel having the highest wheel speed and the wheel speed of the wheel having the lowest wheel speed is equal to or greater than the depressurization threshold value of the ABS control. In this case, the vehicle speed is calculated excluding the wheel speed of the predetermined drive wheel.

  For example, when the wheel speed VW (RL) of the left rear wheel 3RL is the maximum among the wheel speeds of four wheels, the three wheels other than the left rear wheel 3RL (left) are determined from the wheel speed VW (RL) of the left rear wheel 3RL. If the speed difference obtained by subtracting the minimum wheel speed VWMin of the front wheel 3FL, right front wheel 3FR, right rear wheel 3RR) is equal to or greater than the depressurization threshold, the vehicle speed is calculated excluding the wheel speed VW (RL) of the left rear wheel 3RL. Is done. In the present embodiment, the maximum value of the wheel speeds of the front wheels 3FL and 3FR that are rolling wheels among the remaining three wheels is set as the vehicle speed.

With reference to FIG. 3, the details of the driving wheel floating determination 1 and the driving wheel floating determination 2 will be described. Condition (1) is a condition common to driving wheel floating determination 1 and driving wheel floating determination 2.
[Condition (1)]
0 <VWF0 ≦ 15kph
Condition (1) is that the rolling wheel maximum speed VWF0 is greater than 0 and less than or equal to a predetermined upper limit speed. The rolling wheel maximum speed VWF0 is the maximum value of the wheel speeds of the front wheels 3FL and 3FR which are rolling wheels. When an abnormality such as slip occurs in any of the rolling wheels, the wheel speed of the normal wheel where no slip or the like occurs is set as the maximum rolling wheel speed VWF0. The predetermined upper limit speed is set, for example, as a condition in which the rotational speed of the drive wheels 3RL and 3RR increases when the rotational speed of the engine as the drive source 5 is idle and the drive wheels 3RL and 3RR float.

In the driving wheel floating determination 1, the above condition (1) is satisfied, the following conditions (2), (3), and (4) are satisfied, and the following conditions (5) to (8) are continued for a predetermined time. Affirmative determination is made when it is established.
[Condition (2)]
Condition (2) is that the vehicle is in a braking state. For example, the condition (2) is satisfied when the braking operation is performed by the driver and the braking device 7 is operating, or when the braking device 7 is operating due to a braking request in traveling control.
[Condition (3)]
Condition (3) is that ABS control is not performed. When ABS control is not performed, the condition (3) is satisfied.
[Condition (4)]
Condition (4) is that all four wheel speed sensors 12 are valid. When no abnormality is detected in all the wheel speed sensors 12, the condition (4) is satisfied.
[Condition (5)]
Condition (5) is that the wheel speed of the predetermined drive wheel tends to increase. The ECU 50 acquires the wheel speed of each wheel 3 at predetermined intervals, and determines the rear wheel maximum speed VWRearMax, the front wheel maximum speed VWFrontMax, the front wheel minimum speed VWFrontMin, and the rear wheel minimum speed VWRearMin.

  The rear wheel maximum speed VWRearMax is a maximum value of the wheel speeds of the left rear wheel 3RL and the right rear wheel 3RR which are driving wheels. For example, when the wheel speed of the left rear wheel 3RL is larger than the wheel speed of the right rear wheel 3RR, the wheel speed of the left rear wheel 3RL becomes the rear wheel maximum speed VWRearMax, and the left rear wheel 3RL becomes the predetermined drive wheel. In this case, the wheel speed of the right rear wheel 3RR becomes the rear wheel minimum speed VWRearMin.

  The front wheel maximum speed VWFrontMax is the maximum value of the wheel speeds of the left front wheel 3FL and the right front wheel 3FR which are rolling wheels. For example, when the wheel speed of the left front wheel 3FL is larger than the wheel speed of the right front wheel 3FR, the wheel speed of the left front wheel 3FL becomes the front wheel maximum speed VWFrontMax, and the wheel speed of the right front wheel 3FR becomes the front wheel minimum speed VWFrontMin.

  When the wheel speed detected this time is larger than the wheel speed detected last time for the predetermined drive wheel, the condition (5) is satisfied. The ECU 50 determines that the condition (5) is satisfied when the current rear wheel maximum speed VWRearMax is larger than the previous rear wheel maximum speed VWRearMax. If the previous predetermined drive wheel and the current predetermined drive wheel are different wheels 3, the condition (5) is not satisfied. For example, when the wheel speed of the four rear wheels was detected last time, the wheel speed of the left rear wheel 3RL was larger than the wheel speed of the right rear wheel 3RR. When the wheel speed is higher than the wheel speed of the left rear wheel 3RL, it is determined that the condition (5) is not satisfied.

[Condition (6) to Condition (8)]
Conditions (6) to (8) indicate that the wheel speeds of the three wheels 3 other than the predetermined drive wheels tend to decrease. Condition (6) is a condition that the previous value of the front wheel maximum speed VWFrontMax is equal to or greater than the current value. Note that the condition (6) is not satisfied when the wheel 3 for which the front wheel maximum speed VWFrontMax is detected is different between the previous wheel speed detection and the current wheel speed detection.

  Condition (7) is a condition that the previous value of the front wheel minimum speed VWFrontMin is equal to or greater than the current value. Note that the condition (7) is not satisfied when the wheel 3 for which the front wheel minimum speed VWFrontMin is detected differs between the previous wheel speed detection and the current wheel speed detection.

  Condition (8) is a condition that the previous value of the rear wheel minimum speed VWRearMin is greater than or equal to the current value. Note that the condition (8) is not satisfied when the wheel 3 where the rear wheel minimum speed VWRearMin is detected differs between the previous wheel speed detection and the current wheel speed detection.

  When all of the above conditions (6), (7), and (8) are satisfied, it can be determined that the wheel speeds of the three wheels 3 other than the predetermined drive wheels are not increasing and are decreasing. . Note that, in the conditions (6), (7), and (8), it may be a condition that the previous value is larger than the current value.

  In the present embodiment, when the conditions (5) to (8) are all satisfied for a predetermined period of time and the other conditions (1) to (4) are satisfied, the drive wheel An affirmative determination is made in floating determination 1. The predetermined time is, for example, a time that is at least half of the vibration period of the wheel 3. For example, when the vibration frequency of the wheel 3 is 10 to 12 Hz, half of the maximum vibration period is 50 ms. The predetermined time of this embodiment is 60 ms, which is larger than this. Thereby, in the drive wheel floating determination 1, the influence by the vibration of the drive system is suppressed.

The driving wheel floating determination 2 is affirmative when the above conditions (1), (3), and (4) are all satisfied and the following condition (9) is satisfied.
[Condition (9)]
Condition (9) is that the speed difference obtained by subtracting the minimum wheel speed VWMin from the rear wheel maximum speed VWRearMax is equal to or greater than a predetermined speed difference. The minimum wheel speed VWMin is the wheel speed of the wheel 3 having the smallest wheel speed. The predetermined speed difference is determined, for example, so that the increase in the vehicle speed can be determined before decompression due to the lock determination occurs.

  The predetermined speed difference is determined based on, for example, a value obtained by subtracting the lower limit speed from a predetermined upper limit speed. Here, the upper limit speed is, for example, an upper limit of a speed at which the wheel 3 is allowed to be locked in the braking control, and is 10 kph in the present embodiment. The lower limit vehicle speed is, for example, the lower limit of the wheel speed at which a pulse can be detected by the wheel speed sensor 12, and is approximately 3 kph in the present embodiment. When the lower limit speed of 3 kph is subtracted from the upper limit speed of 10 kph, it becomes 7 kph. The predetermined speed difference in this embodiment is 5 kph, which is smaller than 7 kph. In the present embodiment, this predetermined speed difference matches the decompression threshold value of the ABS control.

  The braking force control according to the embodiment will be described with reference to FIG. The control flow shown in FIG. 1 is repeatedly executed at predetermined intervals while the vehicle 100 is traveling. The control flow in FIG. 1 is executed, for example, when the accelerator is OFF.

  First, in step S10, the drive wheel floating determination 1 is made by the ECU 50. When all of the above conditions (1) to (4) are satisfied and the above conditions (5) to (8) are satisfied for a predetermined time, the ECU 50 makes an affirmative determination in the drive wheel floating determination 1 Do. Further, the ECU 50 makes a negative determination in the driving wheel floating determination 1 when the driving wheel floating determination 1 is not positively determined. As a result of the determination in step S10, if an affirmative determination is made in drive wheel floating determination 1 (step S10-Y), the process proceeds to step S40, and if not (step S10-N), the process proceeds to step S20.

  In step S20, the ECU 50 performs driving wheel floating determination 2. The ECU 50 makes an affirmative determination in the drive wheel floating determination 2 when all of the above conditions (1), (3), (4), and (9) are satisfied. In addition, when any one of the above conditions (1), (3), (4), and (9) is not satisfied, the ECU 50 makes a negative determination in the driving wheel floating determination 2. As a result of the determination in step S20, if an affirmative determination is made in driving wheel floating determination 2 (step S20-Y), the process proceeds to step S40, and if not (step S20-N), the process proceeds to step S30.

  In step S30, the ECU 50 determines a selected wheel for the estimated vehicle speed. The ECU 50 calculates the vehicle speed based on the wheel speed of each wheel 3 including the predetermined drive wheel. The ECU 50 of the present embodiment sets the wheel 3 having the maximum wheel speed among the four wheels as the selected wheel, and sets the wheel speed of the selected wheel as the vehicle speed. When step S30 is executed, this control flow ends.

  In step S40, the ECU 50 determines a selected wheel for the estimated vehicle speed. The ECU 50 calculates the vehicle speed excluding the wheel speed of the predetermined drive wheel. The ECU 50 of the present embodiment sets the wheel 3 having the maximum wheel speed among the front wheels 3FL and 3FR as the selected wheel, and sets the wheel speed of the selected wheel as the vehicle speed. When step S40 is executed, the control flow ends.

  As described above, the braking force control device 1-1 of the present embodiment has a case where the wheel speed of the predetermined drive wheel is increasing and the wheel speed of the three wheels other than the predetermined drive wheel is decreasing ( Step S10-Y), the vehicle speed is calculated excluding the wheel speed of the predetermined drive wheel (step S40). If an affirmative determination is made in the driving wheel floating determination 1, it is determined that the vehicle speed has increased, and at least the wheel speed of the predetermined driving wheel is excluded in the calculation of the vehicle speed. According to the braking force control device 1-1 of the present embodiment, the increase in the vehicle speed can be determined earlier, as will be described below.

  For example, as a method for determining the increase in vehicle speed, it is conceivable to make a determination based on the difference between the driving wheel speed and the rolling wheel speed. However, in this determination method, an early determination may be made when the wheel speed of the rolling wheels is greatly reduced by braking. Further, when the driving wheel is lifted, it cannot be determined that the driving wheel speed does not increase to some extent. For this reason, the determination may be delayed and may not be sufficient to suppress the increase in vehicle speed.

  The braking force control device 1-1 according to the present embodiment performs the driving wheel floating determination 1 based on the increasing tendency and decreasing tendency of the wheel speed. Therefore, it is possible to determine the vehicle speed increase early, and to suppress unnecessary vehicle speed increase. As a result, vehicle speed detection errors are suppressed.

  When the difference between the wheel speed of the predetermined drive wheel and the wheel speed of the wheel 3 having the smallest wheel speed is equal to or greater than the depressurization threshold value of the ABS control, the braking force control apparatus 1-1 according to the present embodiment (step S20- Y) The vehicle speed is calculated by excluding the wheel speed of the predetermined drive wheel (step S40). If an affirmative determination is made in the driving wheel floating determination 2, it is determined that the vehicle speed has increased, and at least the wheel speed of the predetermined driving wheel is excluded in the calculation of the vehicle speed. According to the braking force control device 1-1 of the present embodiment, the vehicle speed can be suppressed from rising in a more appropriate range, as will be described below.

  If the wheel speed difference threshold value of the driving wheel floating determination 2 is larger than the ABS control depressurization threshold value, there is a possibility that the minimum speed wheel lock is erroneously determined and the wheel cylinder pressure is depressurized. When the vehicle speed is calculated based on the wheel speed of the predetermined drive wheel that slips due to the float of the wheel 3 or the like, the wheel speed of the other wheel 3 decreases relative to the vehicle speed at which the lift occurred, Erroneously determines that the other wheels 3 are locked even though there is no locking or locking tendency.

  In the braking force control apparatus 1-1 according to the present embodiment, the threshold value of the wheel speed difference in the driving wheel floating determination 2 is based on the pressure reduction threshold value of the ABS control. Therefore, the detection error of the vehicle speed is suppressed, and the reduction of the wheel cylinder pressure due to the erroneous determination can be suppressed in advance. Further, the driving wheel floating determination 2 does not include a braking state (condition (2)) as a determination condition. For this reason, it is possible to determine the increase in the vehicle speed before the start of braking, and to prevent erroneous determination of the lock of the wheels 3.

  Further, the braking force control device 1-1 according to the present embodiment calculates the vehicle speed excluding the wheel speeds of the drive wheels 3RL and 3RR when the affirmative determination is made in the drive wheel lift determination 1 or the drive wheel lift determination 2. To do. When the floating determination is positive for one of the wheel speeds of the drive wheels 3RL and 3RR, there is a possibility that the other wheel speed is also deviated from the true vehicle speed. In this embodiment, an affirmative determination is made in the driving wheel floating determination 1 or the driving wheel floating determination 2, and when the vehicle speed is calculated excluding the wheel speed of the predetermined driving wheel, the vehicle speed is calculated from the wheel speeds of the rolling wheels 3FL and 3FR. Is done. Therefore, the detection error of the vehicle speed is suppressed.

[Release condition]
The release condition common to the driving wheel floating determination 1 and the driving wheel floating determination 2 is that the condition (1) is not satisfied. That is, when the rolling wheel maximum speed VWF0 is greater than 15 kph or when the rolling wheel maximum speed VWF0 is 0 kph, the driving wheel floating determination 1 and the driving wheel floating determination 2 are canceled. Thus, the vehicle speed is calculated based on the wheel speed including the wheel speed of the predetermined drive wheel.

Condition (10) is defined as a release condition for driving wheel floating determination 2.
[Condition (10)]
The condition (10) is that a state where the speed difference obtained by subtracting the minimum wheel speed VWMin from the rear wheel maximum speed VWRearMax is less than 5 kph continues for a predetermined time. The predetermined time of the condition (10) is determined so as not to be erroneously canceled due to low-speed wheel vibration or road surface disturbance, and is 100 ms in this embodiment.

  In the present embodiment, when the driving wheel floating determination 1 and the driving wheel floating determination 2 are switched from a negative determination to an affirmative determination, the guard process regarding the update of the vehicle speed is prohibited or alleviated. In the brake control, when the vehicle speed is updated, a guard process may be performed on the vehicle speed. In the vehicle 100 according to the present embodiment, the acceleration slip determination is made in addition to the driving wheel floating determination 1 and the driving wheel floating determination 2 described above. The acceleration slip determination is to determine the slip of the wheel 3 while the accelerator is ON. In the acceleration slip determination, in the update of the vehicle speed based on the detected wheel speed, an upper limit value is set for the deceleration of the vehicle speed, and a change (decrease) in the vehicle speed exceeding the upper limit value is regulated.

  If the vehicle wheel speed is calculated excluding the wheel speed of the predetermined drive wheel by the positive determination of the drive wheel lift determination 1 and the drive wheel lift determination 2, the calculated vehicle speed may be greatly reduced. is there. At this time, if a guard process is performed against a decrease in the vehicle speed, the increase in the vehicle speed may not be promptly corrected.

  In the present embodiment, when switching from negative determination to positive determination in driving wheel floating determination 1 or driving wheel floating determination 2, the upper limit value of the deceleration of the vehicle speed is changed to a larger deceleration (relaxation of guard processing), Or the guard process by an upper limit is prohibited. As a result, the calculated vehicle speed can be quickly reduced and the increase in the vehicle speed can be suppressed.

  In the present embodiment, the driving wheels are the rear wheels 3RL and 3RR, but the present invention is not limited to this. For example, the driving wheels may be front wheels 3FL and 3FR.

  In the present embodiment, an increase tendency or a decrease tendency of the wheel speed is determined by comparing the current detection value of the wheel speed with the previous value, but the determination method is not limited to this. The increasing tendency or decreasing tendency of the wheel speed may be determined based on the detection / estimation result of the wheel speed at a certain point in time and the detection / estimation result of the wheel speed before that.

  Moreover, in this embodiment, although the driving wheel floating determination 1 is performed prior to the driving wheel floating determination 2, the determination order is not limited to this.

  In the present embodiment, in the calculation / estimation of the vehicle speed, the maximum value of the wheel speed of the wheel 3 that can be selected as the selected wheel is set as the vehicle speed. However, the present invention is not limited to this. For example, the average value of the wheel speeds of the wheels 3 that can be selected as the selected wheel may be the vehicle speed. Moreover, in this embodiment, when the positive determination is made in the driving wheel floating determination 1 and the driving wheel floating determination 2, both the driving wheels 3RL and 3RR are excluded from the selected wheels. Of the driving wheels 3RL and 3RR, Only the predetermined drive wheels may be excluded from the selected wheels.

  The contents disclosed in the above embodiments can be executed in appropriate combination.

1-1 Braking force control device 3 Wheel 3FL Left front wheel (rolling wheel)
3FR Right front wheel (rolling wheel)
3RL Left rear wheel (drive wheel)
3RR Right rear wheel (drive wheel)
7 Braking device 8 Master cylinder 9 Actuator 10 Wheel cylinder 12 Wheel speed sensor 50 ECU (control device)
100 vehicles
VWF0 Rolling wheel maximum speed
VWRearMax Maximum rear wheel speed
VWFrontMax Maximum front wheel speed
VWFrontMin Minimum front wheel speed
VWRearMin Minimum rear wheel speed

Claims (2)

A control device that performs braking force control based on the vehicle speed calculated from the wheel speed,
When the wheel speed of a predetermined driving wheel that is the driving wheel having the highest wheel speed is increasing and the wheel speed of three wheels other than the predetermined driving wheel is decreasing, and the driving wheel having the highest wheel speed is Calculating the vehicle speed excluding the wheel speed of the predetermined drive wheel when the difference between the wheel speed of a predetermined drive wheel and the wheel speed of the wheel having the smallest wheel speed is equal to or greater than the ABS control pressure reduction threshold value. A braking force control device. The braking force control device according to claim 1, wherein when calculating the vehicle speed excluding the wheel speed of the predetermined drive wheel, the vehicle speed is calculated from a wheel speed of a rolling wheel.

Images