JP7484667B2 - Braking Control Device - Google Patents

Description

The present invention relates to a vehicle braking control device.

Patent document 1 describes a braking control device that increases the opportunities for the regenerative braking device to generate power by applying regenerative braking force to a wheel that is experiencing slippage while ABS control is being performed.

JP 2015-93571 A

It is desirable for the braking control device described above to adjust the vehicle body posture while ABS control is being performed. This situation is not limited to when ABS control is being performed, but is generally common when the vehicle is braking as well.

The means for solving the above problems and their effects will be described below.
A braking control device that solves the above problem is a braking control device applied to a vehicle that has a wheel braking device that applies wheel braking force to the wheels of the vehicle and an axle braking device that applies an axle braking force to the axles of the wheels, and is equipped with a control unit that controls the vehicle body attitude by adjusting the distribution ratio for distributing the braking force applied to the vehicle between the wheel braking force and the axle braking force based on a target vehicle body attitude, which is a target for the vehicle body attitude.

When a braking force is applied to the vehicle, a pitching suppression force that suppresses the pitching behavior of the vehicle is generated in the vehicle. When a braking force is applied to the front wheels, an anti-dive force is generated in the vehicle as a pitching suppression force, and when a braking force is applied to the rear wheels, an anti-lift force is generated in the vehicle as a pitching suppression force. In addition, since the axle braking force and the wheel braking force act at different positions, the pitching suppression force generated when the axle braking force is applied to the axle is smaller than the pitching suppression force generated when the wheel braking force is applied to the wheel. Therefore, the braking control device configured as described above adjusts the distribution ratio of the wheel braking force and the axle braking force of the braking force applied to the vehicle based on the target vehicle body attitude. In this way, the braking control device can control the vehicle body attitude when braking the vehicle.

1 is a schematic diagram of a vehicle equipped with a braking control device according to a first embodiment. FIG. 4 is a schematic diagram illustrating forces acting on the vehicle during braking. 4 is a flowchart illustrating a flow of processing performed by the brake control device while ABS control is being performed. 4A and 4B are timing charts when the brake control device performs ABS control. FIG. 11 is a schematic diagram of a vehicle equipped with a braking control device according to a second embodiment. 10 is a flowchart illustrating a flow of processing executed by a brake control device according to a modified example when braking the vehicle.

First Embodiment
The braking control device according to the first embodiment will be described.
FIG. 1 shows a vehicle 10 equipped with a braking control device 100 .

The vehicle 10 is equipped with wheels FR, FL, RR, and RL, an axle 11F that rotates integrally with the front wheels FR, FL, and an axle 11R that rotates integrally with the rear wheels RR, RL, and a braking mechanism 20 that applies a braking force to the wheels FR, FL, RR, and RL.

The brake mechanism 20 is configured so that the higher the pressure of the brake fluid (hereinafter also referred to as "fluid pressure") in the wheel cylinder 21, the greater the force pressing the friction material 23 against the rotating body 22 that rotates integrally with the wheels FL, FR, RL, RR. Therefore, the higher the fluid pressure in the wheel cylinder 21, the greater the braking force applied to the wheels FL, FR, RL, RR. In the following description, the braking force applied to the wheels FR, FL, RR, RL by the operation of the brake mechanism 20 is referred to as the "friction braking force BFP."

The vehicle 10 is equipped with a hydraulic braking device 30 that adjusts the friction braking force BFP by controlling the hydraulic pressure in the wheel cylinder 21. The hydraulic braking device 30 has a hydraulic pressure generating device 31 and a brake actuator 32.

When the driver operates a brake operating member 33 such as a brake pedal, the hydraulic pressure generating device 31 generates hydraulic pressure according to the amount of operation of the brake operating member 33. When the driver operates the brake operating member 33, an amount of brake fluid according to the hydraulic pressure generated by the hydraulic pressure generating device 31 is supplied to the wheel cylinder 21 via the brake actuator 32. The brake actuator 32 individually adjusts the frictional braking force BFP of the wheels FR, FL, RR, and RL by individually controlling the hydraulic pressure in the wheel cylinder 21. For example, the brake actuator 32 can increase or decrease only the frictional braking force BFP applied to the right front wheel FR. In the first embodiment, the frictional braking force BFP corresponds to an example of a "wheel braking force", and the hydraulic braking device 30 corresponds to an example of a "wheel braking device".

The vehicle 10 is equipped with a motor generator 41F for the front wheels FR, FL, and a motor generator 41R for the rear wheels RR, RL.
When the motor generator 41F functions as an electric motor, it applies a driving force to the axle 11F, and when it functions as a generator, it applies a braking force to the axle 11F according to the amount of power generated by the motor generator 41F. Similarly, when the motor generator 41R functions as an electric motor, it applies a driving force to the axle 11R, and when it functions as a generator, it applies a braking force to the axle 11R according to the amount of power generated by the motor generator 41R.

In the following description, the braking force applied to the axles 11F, 11R by the power generation of the motor generators 41F, 41R is referred to as the "regenerative braking force BFR." The motor generators 41F, 41R constitute a regenerative braking device 40 that applies the regenerative braking force BFR to the axles 11F, 11R. In this respect, in the first embodiment, the regenerative braking force BFR corresponds to an example of an "axle braking force," and the regenerative braking device 40 corresponds to an example of an "axle braking device."

When the motor generator 41F applies a driving force or braking force to the axle 11F, the driving force or braking force is applied to both front wheels FR, FL that share the axle 11F. Therefore, in the following description, the motor generator 41F applying a driving force or braking force to the axle 11F is also referred to as "the motor generator 41F applies a driving force or braking force to the front wheels FR, FL." Similarly, when the motor generator 41R applies a driving force or braking force to the axle 11R, the driving force or braking force is applied to both rear wheels RR, RL that share the axle 11R. Therefore, in the following description, the motor generator 41R applying a driving force or braking force to the axle 11R is also referred to as "the motor generator 41R applies a driving force or braking force to the rear wheels RR, RL."

The vehicle 10 is equipped with various sensors for detecting the state of the vehicle 10. In detail, the vehicle 10 is equipped with a wheel speed sensor 51 that detects the wheel speed VW of the wheels FR, FL, RR, and RL, and a stroke sensor 52 that detects the amount of operation of the brake operating member 33. As shown in FIG. 1, the detection signals of the various sensors are input to the brake control device 100.

The vehicle 10 is equipped with a road surface information acquisition device 61 that acquires information about the road surface on which the vehicle 10 is traveling. The information about the road surface on which the vehicle 10 is traveling is an example of information external to the vehicle 10. The road surface information acquisition device 61 is, for example, a camera that can acquire unevenness information about the road surface ahead of the vehicle 10 and a car navigation device that stores map data including the unevenness information about the road surface. The road surface information acquisition device 61 outputs unevenness information about the road surface on which the vehicle 10 will be traveling to the braking control device 100.

The braking control device 100 will now be described.
1, the braking control device 100 includes, as functional units, a control amount derivation unit 101, an allocation ratio derivation unit 102, a braking control unit 103, and a target state value derivation unit 104. In the first embodiment, the allocation ratio derivation unit 102, the braking control unit 103, and the target state value derivation unit 104 constitute an example of a "control unit."

The control quantity derivation unit 101 derives detection values and target values for the control of the hydraulic braking device 30 and the regenerative braking device 40. In detail, the control quantity derivation unit 101 derives the wheel speed VW of the wheels FR, FL, RR, and RL, the vehicle body speed VS, and the slip amount Slp of the wheels FR, FL, RR, and RL based on the detection signal from the wheel speed sensor 51. For example, the slip amount Slp of the right front wheel FR is the difference between the wheel speed VW of the right front wheel FR and the vehicle body speed VS. In addition, the control quantity derivation unit 101 derives the target vehicle braking force BFT, which is the target value of the braking force applied to the vehicle 10, based on the detection signal from the stroke sensor 52, etc. In addition, the control amount derivation unit 101 derives the target wheel braking force BFTW, which is the target value of the braking force applied to the wheels FR, FL, RR, and RL, by distributing the target vehicle braking force BFT to the wheels FR, FL, RR, and RL. The target vehicle braking force BFT is derived for each vehicle, and the target wheel braking force BFTW is derived for each wheel FR, FL, RR, and RL.

The distribution ratio derivation unit 102 derives the distribution ratio α, which is the ratio for distributing the braking force applied to the wheels FR, FL, RR, RL to the regenerative braking force BFR and the frictional braking force BFP, for each of the wheels FR, FL, RR, RL. The distribution ratio α is a value between "0" and "1". When the distribution ratio α is "0", the braking force applied to the wheels FR, FL, RR, RL is only the frictional braking force BFP, and when the distribution ratio α is "1", the braking force applied to the wheels FR, FL, RR, RL is only the regenerative braking force BFR. When the distribution ratio α is greater than "0" and less than "1", both the frictional braking force BFP and the regenerative braking force BFR are applied to the wheels FR, FL, RR, RL.

Next, the relationship between the braking force distribution ratio α and the vehicle body posture will be described with reference to FIG.
As shown in Fig. 2, when braking the vehicle 10, an inertia force Fi, a front wheel braking force F1 acting on the front wheels FR, FL, and a rear wheel braking force F2 acting on the rear wheels RR, RL are applied. The front wheel braking force F1 is the sum of a front wheel friction braking force BFPf acting on the front wheels FR, FL, which is the friction braking force BFP applied to the front wheels FR, FL, and a front wheel regenerative braking force BFRf acting on the front wheels FR, FL, which is the regenerative braking force BFR applied to the front wheels FR, FL. The rear wheel braking force F2 is the sum of a rear wheel friction braking force BFPr acting on the rear wheels RR, RL, which is the friction braking force BFP applied to the rear wheels RR, RL, and a rear wheel regenerative braking force BFRr acting on the rear wheels RR, RL, which is the regenerative braking force BFR applied to the rear wheels RR, RL.

When a braking force is applied to the vehicle 10, in other words, when a front wheel braking force F1 and a rear wheel braking force F2 are applied to the vehicle 10, a load transfer occurs to the front of the vehicle. In this case, nose dive occurs, in which the front of the vehicle sinks, and rear lift occurs, in which the rear of the vehicle lifts.

Therefore, when the front wheel braking force F1 is acting on the vehicle 10, an anti-dive force FAD that prevents the front of the vehicle body from sinking is applied to the vehicle body 12 by the suspension for the front wheels FR, FL. The anti-dive force FAD is a force that acts in a direction that moves the front of the vehicle body away from the road surface. On the other hand, when the rear wheel braking force F2 is acting on the vehicle 10, an anti-lift force FAL that prevents the rear of the vehicle body from lifting is applied to the vehicle body 12 by the suspension for the rear wheels RR, RL. The anti-lift force FAL is a force that acts in a direction that moves the rear of the vehicle body closer to the road surface. The anti-dive force FAD and the anti-lift force FAL are pitching suppression forces that act against the pitching moment M of the vehicle 10.

As shown in FIG. 2, the front wheel friction braking force BFPf and the rear wheel friction braking force BFPr act on the contact points with the road surface of the front wheels FR, FL and the rear wheels RR, RL, respectively, and the front wheel regenerative braking force BFRf and the rear wheel regenerative braking force BFRr act on the axle 11F and the axle 11R, respectively.

The point where the front wheel regenerative braking force BFRf acts is the first point of action PA1, the point where the front wheel friction braking force BFPf acts is the second point of action PA2, the point where the rear wheel regenerative braking force BFRr acts is the third point of action PA3, and the point where the rear wheel friction braking force BFPr acts is the fourth point of action PA4. Furthermore, if the instantaneous rotation center of the front wheels FR, FL is the front wheel rotation center Cf, the first angle θfr, which is the angle between the straight line connecting the first point of action PA1 and the front wheel rotation center Cf and the road surface, is smaller than the second angle θfp, which is the angle between the straight line connecting the second point of action PA2 and the front wheel rotation center Cf and the road surface. Similarly, if the instantaneous center of rotation of the rear wheels RR, RL is the rear wheel rotation center Cr, the third angle θrr, which is the angle between the road surface and the straight line connecting the third application point PA3 and the rear wheel rotation center Cr, is smaller than the fourth angle θrp, which is the angle between the road surface and the straight line connecting the fourth application point PA4 and the rear wheel rotation center Cr.

The anti-dive force FAD and the anti-lift force FAL can be expressed as the following (Equation 1) and (Equation 2) using the first angle θfr, the second angle θfp, the third angle θrr, and the fourth angle θrp.

FAD=BFRf tan(θfr)+BFPf tan(θfp)... (Equation 1)
FAL=BFRr tan(θrr)+BFPr tan(θrp)...(Equation 2)
As shown in Fig. 2, since the second angle θfp is larger than the first angle θfr, the front wheel friction braking force BFPf has a larger contribution to the anti-dive force FAD than the front wheel regenerative braking force BFRf. That is, in (Equation 1), when the front wheel friction braking force BFPf is made larger than the front wheel regenerative braking force BFRf, in other words, when the distribution ratio α of the braking force applied to the front wheels FL, FR is made smaller, the anti-dive force FAD becomes larger. On the other hand, when the front wheel regenerative braking force BFRf is made larger than the front wheel friction braking force BFPf, in other words, when the distribution ratio α of the braking force applied to the front wheels FL, FR is made larger, the anti-dive force FAD becomes smaller.

Similarly, because the fourth angle θrp is greater than the third angle θrr, the rear wheel friction braking force BFPr contributes more to the anti-lift force FAL than the rear wheel regenerative braking force BFRr. In other words, in (Equation 2), when the rear wheel friction braking force BFPr is made greater than the rear wheel regenerative braking force BFRr, in other words, when the distribution ratio α of the braking force applied to the rear wheels RL and RR is made smaller, the anti-lift force FAL becomes greater. On the other hand, when the rear wheel regenerative braking force BFRr is made greater than the rear wheel friction braking force BFPr, in other words, when the distribution ratio α of the braking force applied to the rear wheels RL and RR is made larger, the anti-lift force FAL becomes smaller.

As described above, when the distribution ratio α of the braking forces of the wheels FR, FL, RR, and RL is changed, the pitching suppression force generated in the vehicle 10 changes. The magnitude of the pitching suppression force affects the vehicle body posture. In this way, the distribution ratio derivation unit 102 derives the distribution ratio α of the braking forces for each of the wheels FR, FL, RR, and RL so that the desired vehicle body posture is obtained when braking the vehicle 10.

The braking control unit 103 controls the hydraulic braking device 30 and the regenerative braking device 40 based on the target wheel braking force BFTW derived for each wheel FR, FL, RR, RL and the distribution ratio α derived for each wheel FR, FL, RR, RL. In this way, the braking control unit 103 adjusts the magnitude and type of braking force applied to the wheels FR, FL, RR, RL.

The target state value derivation unit 104 derives a target state value VAT as a state value indicating a target vehicle body attitude.
Hereinafter, a mode in which the vehicle body posture is controlled by adjusting the braking force distribution ratio α in the first embodiment will be described.

During braking of the vehicle 10, slippage may occur in any of the wheels FR, FL, RR, RL. In this case, the brake control device 100 performs anti-lock brake control (hereinafter also referred to as "ABS control") to suppress slippage of the slipping wheel by adjusting the braking force applied to the wheel where slippage has occurred (hereinafter also referred to as the "slipping wheel"). The processing contents of the control amount derivation unit 101 and the allocation ratio derivation unit 102 during the implementation of ABS control will be described below.

The control variable derivation unit 101 derives the target wheel braking force BFTW of the slipping wheel based on the target vehicle braking force BFT and the slip amount Slp. In detail, the control variable derivation unit 101 reduces the target wheel braking force BFTW derived by distributing the target vehicle braking force BFT to the wheels FR, FL, RR, and RL in accordance with the slip amount Slp.

When the reduction condition is satisfied, the control quantity derivation unit 101 reduces the target wheel braking force BFTW of the slipping wheel. The reduction condition is satisfied, for example, when the slip amount Slp of the slipping wheel is greater than the slip determination value SlpTh and the slip amount Slp of the slipping wheel shows an increasing tendency. In addition, when the maintenance condition is satisfied, the control quantity derivation unit 101 maintains the target wheel braking force BFTW of the slipping wheel. The maintenance condition is satisfied, for example, when the slip amount Slp of the slipping wheel is greater than the slip determination value SlpTh but the slip amount Slp of the slipping wheel shows a decreasing tendency. In addition, when the increase condition is satisfied, the control quantity derivation unit 101 increases the target wheel braking force BFTW of the slipping wheel. The increase condition is satisfied, for example, when the slip amount Slp of the slipping wheel is less than the slip determination value SlpTh. Even if the increase condition is met, the target wheel braking force BFTW of the slipping wheel will not be greater than the target wheel braking force BFTW derived by distributing the target vehicle braking force BFT to the wheels FR, FL, RR, and RL.

In addition, the manner in which the target wheel braking force BFTW of the slipping wheel is increased or decreased when ABS control is being performed is not limited to the manner described above. For example, if the target wheel braking force BFTW is decreased and the slip amount Slp of the slipping wheel shows a decreasing tendency, the target wheel braking force BFTW may be increased. In other words, the period during which the target wheel braking force BFTW is held may be omitted.

As a result, when ABS control is being implemented, the braking force applied to the slipping wheel is repeatedly increased and decreased. For this reason, for example, if the front right wheel FR is slipping, the anti-dive force FAD acting on the front right part of the vehicle body is repeatedly increased and decreased, and if the rear left wheel RL is slipping, the anti-lift force FAL acting on the rear left part of the vehicle body is repeatedly increased and decreased. Therefore, there is a concern that the vehicle posture will change due to the repeated increase and decrease in the pitching suppression force while ABS control is being implemented.

Therefore, the distribution ratio derivation unit 102 adjusts the distribution ratio α of the braking force of the slipping wheel so that the vehicle body attitude becomes the target vehicle body attitude, which is the target of the vehicle body attitude, during the implementation of the ABS control. In detail, the distribution ratio derivation unit 102 adjusts the distribution ratio α of the braking force of the slipping wheel based on the target vehicle body attitude and the future change in the vehicle body attitude predicted with the implementation of the ABS control. In the first embodiment, the target vehicle body attitude is the vehicle body attitude immediately before the start of the ABS control, for example, the pitch angle of the vehicle 10 immediately before the start of the ABS control or the change rate of the pitch angle of the vehicle 10. On the other hand, the future change in the vehicle body attitude is the change in the vehicle body attitude predicted with the implementation of the ABS control, and is predicted based on the target wheel braking force BFTW of the slipping wheel. In this way, the distribution ratio derivation unit 102 adjusts the distribution ratio α of the braking force of the slipping wheel so that the vehicle body attitude does not change significantly before and after the implementation of the ABS control. In other embodiments, the target vehicle body attitude can be calculated based on the amount of operation of the brake operating member 33, or can be the vehicle body attitude at the time when the decrease or increase condition of the ABS control is satisfied.

More specifically, the distribution ratio derivation unit 102 adjusts the distribution ratio α of the braking force of the slipping wheel so that the regenerative braking force BFR applied to the slipping wheel changes more than the frictional braking force BFP applied to the slipping wheel. In other words, the distribution ratio derivation unit 102 reduces the range of change in the pitching suppression force by compensating for most of the change in the target wheel braking force BFTW with the change in the regenerative braking force BFR.

However, the distribution ratio derivation unit 102 adjusts the distribution ratio α of the braking force of the slipping wheel within a range in which the frictional braking force BFP does not fall below the predetermined value BFP0. The predetermined value BFP0 is a fixed value determined from the response performance of the hydraulic pressure in the wheel cylinder 21 of the brake mechanism 20. When the frictional braking force BFP is equal to or greater than the predetermined value BFP0, the response speed when varying the frictional braking force BFP is high, and when the frictional braking force BFP is less than the predetermined value BFP0, the response speed when varying the frictional braking force BFP is low. In this way, the predetermined value BFP0 is set as a criterion for determining whether the responsiveness of the frictional braking force BFP is good or bad.

In addition, when braking the vehicle 10, if the braking force distribution ratio α is made too small, in other words, if the frictional braking force BFP applied to the wheels FR, FL, RR, and RL is made too small, the anti-lift force FAL and anti-dive force FAD acting on the vehicle 10 will also become small. In this case, the change in the vehicle body posture associated with the load shift of the vehicle 10 is likely to become large. In this regard, the predetermined value BFP0 may be determined to be a value that can suppress a large change in the vehicle body posture associated with the load shift.

Furthermore, it is preferable that the allocation ratio derivation unit 102 adjusts the allocation ratio α of the slipping wheel so that the friction braking force BFP becomes a default value BFP1 that is greater than the predetermined value BFP0. The default value BFP1 is a value that corresponds to the target wheel braking force BFTW of the slipping wheel when the reduction condition during ABS control is satisfied. For example, the default value BFP1 may be set to a predetermined percentage of the target wheel braking force BFTW of the slipping wheel when the reduction condition during ABS control is satisfied.

The distribution ratio derivation unit 102 may also adjust the distribution ratio α of the braking force of a wheel other than the slipping wheel, in other words, a wheel that is not slipping, during ABS control. For example, if the right front wheel FR is the slipping wheel, the distribution ratio α of the braking force of the right rear wheel RR may be changed, or the distribution ratio α of the braking force of the left rear wheel RL may be changed. The distribution ratio α of the braking force of a wheel other than the slipping wheel may be determined depending on how the vehicle posture is to be controlled. As an example, the distribution ratio α of the braking force of a wheel that is not a slipping wheel may be adjusted so as to offset the change in vehicle posture that occurs when the target wheel braking force BFTW of the slipping wheel is reduced during ABS control.

The brake control device 100 also implements select-low ABS control. Therefore, when ABS control is implemented for the front wheels FR, FL, the distribution ratio derivation unit 102 derives the distribution ratio α of the braking force for the front wheels FR, FL in accordance with which of the front wheels FR, FL is more likely to lock. When ABS control is implemented for the rear wheels RR, RL, the distribution ratio derivation unit 102 derives the distribution ratio α of the braking force for the rear wheels RR, RL in accordance with which of the rear wheels RR, RL is more likely to lock.

The flow of the process executed by the braking control device 100 will be described below with reference to Fig. 3. This process is repeatedly executed in a predetermined control cycle.
As shown in Fig. 3, the brake control device 100 judges whether or not the start condition of the ABS control is satisfied (S11). For example, the brake control device 100 can judge that the start condition is satisfied when the slip amount Slp of any of the wheels FR, FL, RR, and RL exceeds the slip judgment value SlpTh. If the start condition of the ABS control is not satisfied (S11: NO), the brake control device 100 temporarily ends this process. On the other hand, if the start condition of the ABS control is satisfied (S11: YES), the brake control device 100 derives the target wheel braking force BFTW for each of the wheels FR, FL, RR, and RL based on the target vehicle braking force BFT corresponding to the operation amount of the brake operating member 33 (S12). Specifically, the brake control device 100 derives the target wheel braking force BFTW of the slipping wheel based on the target vehicle braking force BFT and the slippage amount Slp, and derives the target wheel braking force BFTW of the non-slipping wheel based on the target vehicle braking force BFT.

Next, the brake control device 100 derives a target state value VAT as a state value indicating the target vehicle body posture (S13). After that, the brake control device 100 derives a braking force distribution ratio α for each wheel FR, FL, RR, RL based on the target state value VAT (S14). This distribution ratio α is determined based on the target state value VAT and future changes in state values predicted with the implementation of ABS control. Then, the brake control device 100 updates the regenerative braking force BFR and friction braking force BFP applied to the wheels FR, FL, RR, RL based on the distribution ratio α (S15). For example, the regenerative braking force BFR applied to the right front wheel FR is calculated by multiplying the target wheel braking force BFTW of the right front wheel FR by the distribution ratio α, and the frictional braking force BFP applied to the right front wheel FR is calculated by multiplying the target wheel braking force BFTW of the right front wheel FR by the value "1-α" obtained by subtracting the distribution ratio α from "1".

Then, the brake control device 100 judges whether or not the termination condition of the ABS control is satisfied (S16). The termination condition is satisfied, for example, when the operation amount of the brake operating member 33 becomes "0" or when the vehicle 10 stops. If the termination condition of the ABS control is not satisfied (S16: NO), the brake control device 100 proceeds to step S12. If the termination condition of the ABS control is satisfied (S16: YES), the brake control device 100 terminates this process.

The operation and effects of the first embodiment will be described.
In more detail, a case where a wheel slips when the target wheel braking force BFTW of the wheel is constant will be described with reference to Figures 4(a) and 4(b). In Figure 4(a), the wheel speed VWS of the wheel where slipping occurs is shown by a solid line.

As shown in Figures 4(a) and (b), at a first time t11, the slip amount Slp of a certain wheel begins to increase. Then, at a second time t12 when the slip amount Slp of the wheel where slip has occurred (hereinafter also referred to as the "slipping wheel") becomes equal to or greater than the slip determination value SlpTh, ABS control for the slipping wheel is initiated.

In the period from the second timing t12 to the third timing t13, the slip amount Slp of the slipping wheel increases. Therefore, the period from the second timing t12 to the third timing t13 is a reduction period T1 in which the target wheel braking force BFTW of the slipping wheel is reduced. In other words, the braking force applied to the slipping wheel is reduced.

During the reduction period T1, the entire reduction in the target wheel braking force BFTW is covered by the reduction in the regenerative braking force BFR. In other words, during the reduction period T1, the regenerative braking force BFR is reduced while the magnitude of the frictional braking force BFP is maintained constant. Therefore, during the reduction period T1, the distribution ratio α is reduced. As a result, the change in the pitching suppression force associated with the reduction in the braking force applied to the slipping wheel is suppressed. Note that the magnitude of the frictional braking force BFP applied to the slipping wheel from the second timing t12 onwards is determined based on the magnitude of the target wheel braking force BFTW at the start timing of the reduction period T1.

Next, in the period from the third timing t13 to the fourth timing t14, the slip amount Slp of the slipping wheel decreases. Therefore, the period from the third timing t13 to the fourth timing t14 becomes the maintenance period T2 during which the target wheel braking force BFTW of the slipping wheel is maintained. In other words, the braking force applied to the slipping wheel is kept constant. In the maintenance period T2, the distribution ratio α is maintained.

Next, in the period from the fourth timing t14 to the fifth timing t15, the slip amount Slp of the slipping wheel becomes less than the slip determination value SlpTh. Therefore, the period from the fourth timing t14 to the fifth timing t15 becomes the increase period T3 in which the target wheel braking force BFTW of the slipping wheel is increased. In other words, the braking force applied to the slipping wheel is increased.

During the increase period T3, the entire increase in the target wheel braking force BFTW is covered by the increase in the regenerative braking force BFR. In other words, during the increase period T3, the regenerative braking force BFR increases while the magnitude of the frictional braking force BFP is maintained constant. Therefore, during the increase period T3, the distribution ratio α increases. As a result, the change in the pitching suppression force that accompanies the increase in the braking force applied to the slipping wheel is suppressed.

At the fifth timing t15, the slip amount Slp of the slipping wheel again becomes equal to or greater than the slip determination value SlpTh. Therefore, the reduction period T1 begins from the fifth timing t15. The magnitude of the friction braking force BFP applied to the slipping wheel from the fifth timing t15 onwards is determined based on the magnitude of the target wheel braking force BFTW at the start timing of the reduction period T1. The target wheel braking force BFTW at the fifth timing t15 is smaller than the target wheel braking force BFTW at the second timing t12. Therefore, the friction braking force BFP at the fifth timing t15 is smaller than the friction braking force BFP at the second timing t12.

When the increasing tendency of the slip amount Slp is eliminated after the fifth timing t15, the decrease period T1 ends and the maintenance period T2 begins. After that, when the slip amount Slp becomes less than the slip determination value SlpTh, the maintenance period T2 ends and the increase period T3 begins. Thus, during the implementation of ABS control, the decrease period T1, the maintenance period T2, and the increase period T3 are repeated. In other words, during the implementation of ABS control, the pitching suppression force acting on the vehicle body part supporting the slipping wheel increases or decreases as the braking force applied to the slipping wheel increases or decreases. In this regard, in the first embodiment, the increase or decrease in the braking force applied to the slipping wheel is realized by increasing or decreasing the regenerative braking force BFR applied to the slipping wheel, so that the increase or decrease in the pitching suppression force acting on the vehicle body part supporting the slipping wheel is suppressed. As a result, the vehicle body posture during the implementation of ABS control is suppressed from changing significantly from the vehicle body posture immediately before the ABS control, which is the target vehicle body posture.

As shown in FIG. 4, when ABS control is being performed, a frictional braking force BFP greater than a predetermined value BFP0 is applied to the slipping wheel. In other words, a certain amount of brake fluid is stored in the wheel cylinder 21 provided for the slipping wheel. Therefore, in a situation where it becomes necessary to change the frictional braking force BFP while ABS control is being performed, a decrease in the response speed of the frictional braking force BFP can be suppressed, unlike when the frictional braking force BFP is less than the predetermined value BFP0.

In addition, while ABS control is being performed, a frictional braking force BFP is applied to the slipping wheel according to the target wheel braking force BFTW at the start timing of the reduction period T1. This allows for a quick response, for example, when it is desired to reduce the braking force distribution ratio α of the slipping wheel after the end of ABS control, in other words, when it is desired to increase the proportion of the frictional braking force BFP in the target wheel braking force BFTW.

Note that, during ABS control, it is preferable to control changes in vehicle posture accompanying the implementation of ABS control by adjusting the distribution ratio α of the braking force of the wheels that are not slipping wheels. For example, if the pitching suppression force is decreasing due to a reduction in the braking force applied to the slipping wheels, it is preferable to reduce the distribution ratio α of the braking force applied to the wheels whose braking force is not fluctuating due to ABS control. This makes it possible to suppress the reduction in pitching suppression force caused by the reduction in the braking force of the slipping wheels. In this way, even if the vehicle posture changes due to a change in the magnitude of the braking force applied to the slipping wheels, the change in vehicle posture can be controlled by adjusting the distribution ratio α of the braking force of the wheels that are not slipping wheels.

Second Embodiment
A brake control device 100A according to the second embodiment will be described. In the following description, the same reference numerals will be used to designate components common to or corresponding to those in the first embodiment, and duplicated descriptions will be omitted.

As shown in FIG. 5, the vehicle 10 is equipped with a vehicle integrated control device 200. The vehicle integrated control device 200 transmits various commands when the vehicle 10 is driven by automatic driving to another control device that controls the on-vehicle actuators. The on-vehicle actuators include, for example, a hydraulic braking device 30, motor generators 41F, 41R, and a steering device that adjusts the steering angle of the front wheels FR, FL. The control device also includes, for example, a drive control device that controls the motor generators 41F, 41R that function as electric motors, a brake control device 100A that controls the motor generators 41F, 41R that function as generators and the hydraulic braking device 30, and a steering control device that controls the steering device. When the brake control device 100A receives a braking command and a stop command from the vehicle integrated control device 200, it drives the hydraulic braking device 30 to control the braking force applied to the vehicle 10.

When the vehicle 10 is not in autonomous driving, the control quantity derivation unit 101 derives the target vehicle braking force BFT based on the detection signal from the stroke sensor 52, etc., and when the vehicle 10 is in autonomous driving, the control quantity derivation unit 101 derives the target vehicle braking force BFT based on the signal input from the vehicle integrated control device 200.

The allocation ratio derivation unit 102 derives a ratio (hereinafter also referred to as "allocation ratio β") for allocating the braking force applied to the vehicle 10 to the regenerative braking force BFR and the frictional braking force BFP. In the second embodiment, the allocation ratio β of the braking force is not derived for each of the wheels FR, FL, RR, and RL, but is derived for the vehicle 10. In other words, when the allocation ratio β is "0", of the regenerative braking force BFR and the frictional braking force BFP, only the frictional braking force BFP is applied to the vehicle 10. On the other hand, when the allocation ratio β is "1", of the regenerative braking force BFR and the frictional braking force BFP, only the regenerative braking force BFR is applied to the vehicle 10.

Note that "automated driving" in the second embodiment includes automatic adjustment of the acceleration and deceleration of the vehicle 10 on the vehicle 10 side. In other words, if the vehicle 10 is driven without the driver's accelerator and brake operations, it is considered to be automatic driving whether the steering angle control is automatically adjusted on the vehicle 10 side or the steering angle is adjusted by the driver's steering operation.

In the second embodiment, the vehicle body posture is controlled by adjusting the braking force distribution ratio β. In the following description, the act of the driver manually driving the vehicle 10 is referred to as "manual driving."

When the vehicle 10 decelerates during manual driving, it may be preferable for the vehicle 10 to produce pitching behavior in response to the deceleration in order to inform the driver that the vehicle 10 is decelerating. On the other hand, when the vehicle 10 decelerates during automatic driving, it may be preferable for the vehicle 10 not to produce pitching behavior in response to the deceleration in order to improve the ride comfort of the occupants, including the driver. In other words, the target vehicle body attitude when the vehicle 10 decelerates may differ depending on whether or not the driver of the vehicle 10 is performing a driving operation.

As explained in the first embodiment, when the braking force applied to the front wheels FR, FL is constant, the greater the regenerative braking force BFR applied to the front wheels FR, FL, the smaller the anti-dive force FAD generated in the vehicle 10. Also, when the braking force applied to the rear wheels RR, RL is constant, the greater the regenerative braking force BFR applied to the rear wheels RR, RL, the smaller the anti-lift force FAL generated in the vehicle 10.

In other words, by changing the braking force distribution ratio β, the pitching suppression force generated in the vehicle 10 can be changed. For example, by changing the braking force distribution ratio β so that the pitching suppression force generated in the vehicle 10 is reduced, the pitching behavior of the vehicle 10 during deceleration can be increased. On the other hand, by changing the braking force distribution ratio β so that the pitching suppression force generated in the vehicle 10 is increased, the pitching behavior of the vehicle 10 during deceleration can be reduced. Note that "large pitching behavior" here means that the pitch angle of the vehicle 10 is increased or the rate of change of the pitch angle of the vehicle 10 is increased.

Therefore, the allocation ratio derivation unit 102 sets the target vehicle body attitude depending on whether or not the driver of the vehicle 10 is performing a driving operation. This will be described in detail below.
When the vehicle 10 decelerates during manual driving, it is preferable that the vehicle body attitude change according to the deceleration of the vehicle 10. For this reason, when the vehicle 10 decelerates during manual driving, the allocation ratio derivation unit 102 sets a target vehicle body attitude so that a pitching behavior occurs according to the deceleration of the vehicle 10, and derives an allocation ratio β of the braking force. Note that, during manual driving, the allocation ratio derivation unit 102 may derive an allocation ratio β that causes the vehicle 10 to produce a pitching behavior larger than the pitching behavior according to the deceleration.

On the other hand, when the vehicle 10 decelerates during autonomous driving, it is preferable that the vehicle body attitude does not change according to the deceleration of the vehicle 10. For this reason, when the vehicle 10 decelerates during autonomous driving, the distribution ratio derivation unit 102 sets a target vehicle body attitude so that the vehicle 10 does not exhibit pitching behavior according to the deceleration, and derives the distribution ratio β of the braking force. Note that even during autonomous driving, if it becomes necessary to inform the occupants that the vehicle 10 is decelerating, the distribution ratio β of the braking force may be derived so that the vehicle 10 exhibits pitching behavior according to the deceleration.

As an example, the allocation ratio derivation unit 102 may use two allocation ratios β of different magnitudes depending on whether there is a request to increase the pitching behavior of the vehicle 10 or whether there is a request to decrease the pitching behavior of the vehicle 10.

The operation and effects of the second embodiment will be described.
In a situation where the manually driven vehicle 10 is decelerating, the braking force distribution ratio β changes in a direction that reduces the pitching suppression force of the entire vehicle 10. By changing the distribution ratio β in this manner, the pitching behavior of the vehicle 10 becomes relatively large. In other words, the ride comfort of the vehicle 10 for the driver is improved in that the vehicle body attitude of the vehicle 10 changes in response to the braking request of the driver.

On the other hand, when the vehicle 10 decelerates during autonomous driving, the braking force distribution ratio β changes in a direction that increases the pitching suppression force of the vehicle 10 as a whole. By changing the distribution ratio β in this way, the pitching behavior of the vehicle 10 becomes relatively small. In other words, the ride comfort of the vehicle 10 for the occupants, including the driver, is improved in that changes in the vehicle body posture of the vehicle 10 are suppressed.

(Example of change)
The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

The braking control device 100 may adjust the distribution ratio α of the braking forces of the wheels FR, FL, RR, and RL based on the results of a comparison between the vehicle body posture when braking the vehicle 10 and an arbitrary target vehicle body posture, regardless of whether ABS control is being performed. Below, the flow of the processing performed by the braking control device 100 will be described with reference to FIG. 6.

As shown in FIG. 6, the brake control device 100 determines whether the target vehicle braking force BFT is greater than "0", in other words, whether there is a braking request (S21). If the target vehicle braking force BFT is "0" (S21: NO), the brake control device 100 ends this process. On the other hand, if the target vehicle braking force BFT is greater than "0" (S21: YES), the brake control device 100 derives an actual state value VA as a state value indicating the current vehicle body attitude, and a target state value VAT as a state value indicating the target vehicle body attitude (S22, S23).

For example, if the actual state value VA is the pitch angle, the target state value VAT is the target pitch angle. The actual state value VA and the target state value VAT may be the rate of change of the pitch angle, a value indicating the magnitude of the rolling behavior of the vehicle body, a value indicating the magnitude of the yawing behavior of the vehicle body, or other values. The target state value VAT may be a value according to the target vehicle braking force BFT, a value according to the driving speed, a value according to the driver's preference, or other values. If the target state value VAT is a fixed value, the processing of step S23 may be omitted.

The brake control device 100 then derives a distribution ratio α of the braking forces of the wheels FR, FL, RR, and RL so that the difference between the actual state value VA and the target state value VAT is reduced (S24). For example, if the pitch angle corresponding to the target state value VAT is smaller than the pitch angle corresponding to the actual state value VA, the distribution ratio α is derived so that the pitch angle is reduced. Then, the brake control device 100 updates the regenerative braking force BFR and the frictional braking force BFP applied to the wheels FR, FL, RR, and RL (S25).

This modification can bring the vehicle body posture during braking of the vehicle 10 closer to the target vehicle body posture, thereby improving the ride comfort of passengers including the driver.
In the modification example described with reference to Fig. 6, the distribution ratio α for each wheel FR, FL, RR, RL is set based on the actual state value VA and the target state value VAT. However, the distribution ratio β may be set based on the actual state value VA and the target state value VAT.

- If there are irregularities on the road surface on which the vehicle 10 is traveling, there is a risk that the vehicle body posture will change when the wheels FR, FL, RR, and RL overcome the irregularities in the road surface. Therefore, when the brake control device 100 applies braking force to the vehicle 10 in a situation where the vehicle 10 is traveling on a road surface with irregularities, it is preferable that the brake control device 100 adjusts the braking force distribution ratio α so that the above-mentioned change in vehicle body posture is small.

The braking control device 100 predicts future changes in the vehicle body posture based on the information output from the road surface information acquisition device 61. For example, when both front wheels FR, FL approach an upward slope, it is predicted that nose lift will occur in the vehicle 10, and when both front wheels FR, FL approach a downward slope, it is predicted that nose dive will occur in the vehicle 10.

The brake control device 100 then derives a braking force distribution ratio α based on the predicted future changes in vehicle body attitude and the target vehicle body attitude. In detail, the brake control device 100 derives a braking force distribution ratio α so as to cancel out changes in vehicle body attitude caused by input from the road surface. For example, when nose lift is predicted to occur in the vehicle 10, the distribution ratio α is derived so that the front wheel friction braking force BFPf becomes large. Then, the brake control device 100 updates the regenerative braking force BFR and the friction braking force BFP applied to the wheels FR, FL, RR, and RL.

This modified example can increase the anti-lift force acting on the front of the vehicle body when the vehicle 10 experiences nose lift due to unevenness in the road surface, and can increase the anti-dive force acting on the front of the vehicle body when the vehicle 10 experiences nose dive. This modified example can therefore suppress changes in vehicle posture caused by unevenness in the road surface.

In the first embodiment, the distribution ratio derivation unit 102 may set the distribution ratio α of the braking force of the slipping wheel to "1". In other words, the target wheel braking force BFTW of the slipping wheel associated with the implementation of ABS control may be provided only by the regenerative braking force BFR applied to the slipping wheel.

- In the first embodiment, if there is a request to inform the driver of changes in vehicle body posture accompanying the implementation of ABS control, the distribution ratio derivation unit 102 may set the distribution ratio α of the braking force of the slipping wheel to "0". In other words, the change in the target wheel braking force BFTW of the slipping wheel accompanying the implementation of ABS control may be covered only by the frictional braking force BFP applied to the slipping wheel.

In the first embodiment, the distribution ratio derivation unit 102 may derive the distribution ratio α of the braking force of the slipping wheel so as not to change the frictional braking force BFP while ABS control is being performed. In this case, the frictional braking force BFP may be kept unchanged from a predetermined value BFP0, or may be kept unchanged from the frictional braking force BFP at the time when the start condition of ABS control is satisfied.

The braking control devices 100, 100A may adjust the distribution ratios α, β when the driving force required of the vehicle 10 changes, when the steering amount of the vehicle 10 changes, when the control amount of the active suspension changes, etc.

When the driving force required of the vehicle 10 increases, in other words, when the vehicle 10 accelerates, a load shift occurs to the rear of the vehicle, causing the vehicle 10 to pitch. Specifically, unlike when the vehicle 10 decelerates, nose lift occurs, in which the front of the vehicle body rises up, and rear dive occurs, in which the rear of the vehicle body sinks down. In this case, the braking control device 100, 100A may apply a braking force to the vehicle 10 that does not affect the acceleration of the vehicle 10. Furthermore, the braking control device 100, 100A may adjust the braking force distribution ratios α, β to suppress changes in the vehicle body posture associated with the acceleration of the vehicle 10. This makes it possible to suppress changes in the vehicle body posture associated with the acceleration of the vehicle 10.

When the vehicle 10 is braked, if the steering amount of the vehicle 10 increases, in other words, when the vehicle 10 turns, a load shift occurs in the width direction, causing the vehicle 10 to exhibit a rolling behavior. Therefore, the brake control device 100, 100A may adjust the braking force distribution ratios α, β to suppress changes in the vehicle body posture that accompany the turning of the vehicle 10. This makes it possible to suppress changes in the vehicle body posture that accompany the turning of the vehicle 10.

In a vehicle equipped with an active suspension, when the control amount of the active suspension changes, in other words, when the spring constant and damping coefficient of the suspension change, the vehicle body posture changes. Therefore, the braking control device 100, 100A may adjust the braking force distribution ratios α, β to suppress changes in vehicle body posture caused by control of the active suspension. This makes it possible to suppress changes in vehicle body posture caused by changes in the control amount of the active suspension.

- The brake control device 100, 100A may set the target vehicle body attitude based on the preferences of the occupants, including the driver. For example, the brake control device 100, 100A may set the target vehicle body attitude based on the driver's past driving history, or the driver may select a parameter that indicates the extent to which the driver's driving content is reflected in the vehicle body attitude. In this modified example, the change in the vehicle body attitude during braking, etc. can be changed according to the preferences of the occupants, including the driver. An example of the driver's past driving history is the operation speed of the driver's brake operating member 33. For drivers who tend to operate at high speeds, the target vehicle body attitude may be set so that the pitch angle is large.

- ABS control can be performed not only when the driver operates the brake operating member 33, but also when braking force is applied to the wheels FR, FL, RR, and RL of the vehicle 10 during autonomous driving. Therefore, the brake control device 100 according to the first embodiment can also be applied to a brake control device for an autonomous vehicle.

- The vehicle 10 does not need to be equipped with a hydraulic braking device 30 as long as it can apply a frictional braking force BFP to the wheels FR, FL, RR, and RL. For example, instead of the hydraulic braking device 30, the vehicle 10 may be equipped with an electric braking device that moves the friction material 23 relative to the rotating body 22 by driving a motor. In this case, the electric braking device corresponds to an example of a "wheel braking device."

The braking force due to the engine brake can be considered an example of an "axle braking force" acting on the axles of the wheels FR, FL, RR, and RL. In other words, if the vehicle 10 is equipped with an automatic transmission, the axle braking force can be changed by switching the gear ratio. In this case, the automatic transmission of the vehicle 10 corresponds to an example of an "axle braking device."

- The vehicle 10 may be equipped with only one of the motor generator 41F for the front wheels FR, FL and the motor generator 41R for the rear wheels RR, RL. In other words, the vehicle 10 may be a vehicle that can apply regenerative braking force BFR to only one of the front wheels FR, FL and the rear wheels RR, RL. The vehicle 10 may also be equipped with a motor generator for the right front wheel FR and a motor generator for the left front wheel FL, or a motor generator for the right rear wheel RR and a motor generator for the left rear wheel RL, or a motor generator for each of the wheels FR, FL, RR, RL.

- When the vehicle 10 is equipped with a motor generator for each of the wheels FR, FL, RR, and RL, the distribution ratio derivation unit 102 can adjust only the distribution ratio α of the braking force of any one of the wheels FR, FL, RR, and RL. For example, when the distribution ratio α of the braking force of the right front wheel FR is changed without changing the distribution ratio α of the braking force of the left front wheel FL, the anti-dive force FAD of the right front part of the vehicle body changes without changing the anti-dive force FAD of the left front part of the vehicle body. Similarly, when the distribution ratio α of the braking force of the left rear wheel RL is changed without changing the distribution ratio α of the braking force of the right rear wheel RR, the anti-lift force FAL of the left rear part of the vehicle body changes without changing the anti-lift force FAL of the right rear part of the vehicle body. Therefore, in a situation where a braking force is applied to the vehicle 10 while it is turning, the brake control device 100 can adjust the roll angle of the vehicle 10 and the rate of change of the roll angle by varying the distribution ratio α of the braking force of the right wheels FR, RR and the distribution ratio α of the braking force of the left wheels RR, RL.

The braking control device 100, 100A may have any of the following configurations (a) to (c): (a) It has one or more processors that execute various processes according to a computer program. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute the processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer. (b) It has one or more dedicated hardware circuits that execute various processes. The dedicated hardware circuits are, for example, application specific integrated circuits, i.e., ASICs (Application Specific Integrated Circuits), or FPGAs (Field Programmable Gate Arrays). (c) It has a processor that executes some of the various processes according to a computer program, and dedicated hardware circuits that execute the remaining processes of the various processes.

10: vehicle; 11F, 11R: axle; 20: brake mechanism; 21: wheel cylinder; 30: hydraulic brake device (an example of a wheel brake device)
40...Regenerative braking device (an example of an axle braking device)
61... Road surface information acquisition device 100, 100A... Braking control device 101... Control amount derivation unit 102... Allocation ratio derivation unit 103... Braking control unit FR, FL, RR, RL... Wheels BFT... Target vehicle braking force BFTW... Target wheel braking force BFR... Regenerative braking force (an example of an axle braking force)
BFP: Friction braking force (an example of wheel braking force)
BFP0: Predetermined value α, β: Allocation ratio

Claims (6)

A braking control device applied to a vehicle including a wheel braking device that applies a wheel braking force to a wheel of the vehicle, and an axle braking device that applies an axle braking force to an axle of the wheel, comprising:
a control unit that controls the vehicle body attitude by adjusting an allocation ratio for allocating a braking force to be applied to the vehicle to the wheel braking force and the axle braking force, based on a target vehicle body attitude that is a target for the vehicle body attitude of the vehicle and a change in the vehicle body attitude that is predicted in the future ;
The control unit predicts a future change in the vehicle body attitude based on at least one of a change in a braking force applied to the vehicle, a change in a driving force applied to the vehicle, and a change in a steering.
A braking control device comprising: A braking control device applied to a vehicle including a wheel braking device that applies a wheel braking force to a wheel of the vehicle, and an axle braking device that applies an axle braking force to an axle of the wheel, comprising:
a control unit that controls the vehicle body attitude by adjusting an allocation ratio for allocating a braking force to be applied to the vehicle to the wheel braking force and the axle braking force, based on a target vehicle body attitude that is a target for the vehicle body attitude of the vehicle and a change in the vehicle body attitude that is predicted in the future ;
The control unit predicts a future change in the vehicle body attitude based on information outside the vehicle.
A braking control device comprising: A braking control device applied to a vehicle including a wheel braking device that applies a wheel braking force to a wheel of the vehicle, and an axle braking device that applies an axle braking force to an axle of the wheel, comprising:
a control unit that controls the vehicle body attitude by adjusting an allocation ratio for allocating a braking force applied to the vehicle to the wheel braking force and the axle braking force based on a target vehicle body attitude that is a target for a vehicle body attitude of the vehicle ,
The control unit sets the target vehicle body attitude depending on whether or not a driving operation is performed by a driver of the vehicle.
A braking control device comprising: A braking control device applied to a vehicle including a wheel braking device that applies a wheel braking force to a wheel of the vehicle, and an axle braking device that applies an axle braking force to an axle of the wheel, comprising:
a control unit that controls the vehicle body attitude by adjusting an allocation ratio for allocating a braking force applied to the vehicle to the wheel braking force and the axle braking force based on a target vehicle body attitude that is a target for a vehicle body attitude of the vehicle ,
During antilock brake control for suppressing slip of a slipping wheel that is one of the wheels that has experienced slip during braking of the vehicle, the control unit adjusts the distribution ratio of the braking force of the slipping wheel so that the axle braking force applied to the slipping wheel changes more than the wheel braking force applied to the slipping wheel.
A braking control device comprising: A braking control device applied to a vehicle including a wheel braking device that applies a wheel braking force to a wheel of the vehicle, and an axle braking device that applies an axle braking force to an axle of the wheel, comprising:
a control unit that controls the vehicle body attitude by adjusting an allocation ratio for allocating a braking force applied to the vehicle to the wheel braking force and the axle braking force based on a target vehicle body attitude that is a target for a vehicle body attitude of the vehicle ,
The control unit includes:
During the execution of antilock brake control for suppressing slip of a slipping wheel, which is a wheel that has experienced slip during braking of the vehicle, among the wheels,
The distribution ratio of the braking force of the slipping wheel is adjusted so that the wheel braking force applied to the slipping wheel corresponds to a target value of the braking force applied to the slipping wheel at a start timing of a period in which the braking force applied to the slipping wheel is reduced.
A braking control device comprising: A braking control device applied to a vehicle including a wheel braking device that applies a wheel braking force to a wheel of the vehicle, and an axle braking device that applies an axle braking force to an axle of the wheel, comprising:
a control unit that controls the vehicle body attitude by adjusting an allocation ratio for allocating a braking force applied to the vehicle to the wheel braking force and the axle braking force based on a target vehicle body attitude that is a target for a vehicle body attitude of the vehicle ,
During antilock brake control for suppressing slip of a slipping wheel that is a wheel that has slipped during braking of the vehicle, the control unit adjusts the distribution ratio of the braking force of a wheel other than the slipping wheel among the wheels so as to offset a change in the vehicle body posture that occurs due to adjustment of the distribution ratio of the braking force of the slipping wheel.
A braking control device comprising: