JPH11217017A - Suspension control device for vehicle mounted with behavior control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal pressure control of a suspension cylinder, which improves a behavior control effect of an automatic brake, so that desirably, there is no change in the posture of the vehicle body. SOLUTION: When a behavior control is not working, shown with broken underlines, internal pressures of cylinders for front wheels 11FR and 11FL are increased by an amount αcorresponding to a reduction in speed, while internal pressures of cylinders for rear wheels 11RR, 11RL are decreased by an amount β corresponding to the reduction in speed, for controlling pitching. When under a behavior control of a braking FVR of the right front wheel 11FR, shown with solid underlines, an internal pressure of the cylinder thereof is increased by an amount (ΔKXG×XG corresponding to a reduction in speed XG while an internal pressure of the cylinder for the left front wheel 11FL is decreased by the same amount, and an internal pressure of the cylinder for the right rear wheel 11RR is decreased by the same amount, and an internal pressure of the cylinder for the left rear wheel 11RL is increased by the same amount. The right front wheel 11FR increases its braking force to FVR due to the rise in internal pressure, for increasing its behavior control effect. A sum of the internal pressures of the cylinders for the front left and right wheels equals a sum of the internal pressures of the cylinders for the rear left and right wheels, so that a pitching posture remains constant. A sum of the internal pressures of the cylinders for the right-side front and rear wheels equals a sum of the internal pressures of the cylinders for the left-side front and rear wheels, so that a rolling posture remains constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control apparatus for improving the behavior control effect of a vehicle equipped with a behavior control apparatus for controlling a horizontal plane behavior of a vehicle by an automatic brake. The present invention relates to a suspension control device capable of realizing an improvement in the behavior control effect while suppressing a posture change as much as possible.

[0002]

2. Description of the Related Art As a vehicle behavior control device, for example, as described in Japanese Patent Laid-Open No. 7-89427, the vehicle horizontal surface behavior is controlled by an automatic brake for each wheel so as to be as desired. Such is known. This behavior control device improves the running stability of the vehicle by automatically braking the corresponding wheel so as to reduce the estimated side slip of the vehicle when the estimated side slip is larger than a set value.

[0003]

In the conventional behavior control apparatus, when enhancing the behavior control effect, the brake fluid pressure to the wheels to be braked by the automatic brake is increased to increase the automatic braking force. However, this measure causes a new problem that the vehicle becomes unstable due to wheel slip on a road surface having a very low friction coefficient such as an icy road.

According to the first aspect of the present invention, when the automatic braking force is increased, the automatic braking force is increased by increasing the wheel load of the wheel to be braked by the automatic braking. It is another object of the present invention to propose a suspension control device embodying this idea from the viewpoint that the behavior control effect can be enhanced without causing the new behavior instability even on a low friction road surface.

[0005] A second aspect of the present invention is to propose a suspension control device which can suitably achieve the operation and effect of the first invention when the suspension has a pitching control device. .

A third object of the present invention is to provide a suspension control device capable of achieving the effects of the second invention while maintaining the effect of suppressing pitching by the pitching control device.

A fourth object of the present invention is to provide a suspension control device capable of achieving the effects of the third invention without causing a change in the attitude of the vehicle in the rolling direction. .

[0008] A fifth aspect of the present invention is a second aspect of the present invention.
It is an object of the fourth invention to propose a suspension control device in which the vehicle attitude does not become unnatural.

According to a sixth aspect of the present invention, there is provided a suspension control apparatus capable of suitably achieving the effects of the first aspect of the invention when the suspension is capable of changing the damping force of a shock absorber. The purpose is to do.

[0010] A seventh aspect of the present invention proposes a suspension control device capable of suitably achieving the function and effect of the sixth aspect of the present invention when the wheels to be braked by the automatic brake are front wheels. Aim.

According to an eighth aspect of the present invention, there is provided a suspension control apparatus capable of suitably achieving the function and effect of the sixth aspect of the present invention when the wheels to be braked by the automatic brake are rear wheels. With the goal.

[0012]

To achieve these objects, a suspension control device for a vehicle equipped with a behavior control device according to the first invention comprises a vehicle behavior control device for controlling a vehicle horizontal surface behavior by an automatic brake. In a vehicle in which wheels are suspended by suspensions capable of individually controlling the wheel loads on the respective wheels, a wheel load of the wheels during the automatic braking is increased when the vehicle behavior control by the vehicle behavior control device is not performed than when the vehicle is not controlled. In order to control the suspension, the suspension is controlled.

According to a second aspect of the present invention, there is provided a suspension control apparatus for a vehicle equipped with a behavior control apparatus, wherein the suspension controls the wheel load of each wheel individually according to braking deceleration to suppress pitching of the vehicle. In this case, the wheel load control gain for the braking deceleration is changed to increase the wheel load of the wheel during automatic braking.

According to a third aspect of the present invention, there is provided the suspension control device for a vehicle equipped with the behavior control device according to the second aspect of the invention, wherein the wheel load of the wheel on the opposite side of the vehicle in the vehicle width direction is reduced by the same load. Thus, the load control gain for the wheel is configured to be changed.

According to a fourth aspect of the present invention, there is provided the suspension control device for a vehicle equipped with the behavior control device according to the third aspect, wherein the wheel load of the other wheel on the same side in the vehicle width direction as the wheel whose load has been increased is reduced by the same load. And the load control gain related to the wheel is changed so that the wheel load of the wheel on the opposite side of the vehicle width direction from the wheel is increased by the same load. It is characterized by having done.

According to a fifth aspect of the present invention, there is provided a suspension control apparatus for a vehicle equipped with a behavior control apparatus according to any one of the second to fourth aspects, wherein a limit is set to a change amount of a load control gain related to each wheel. Things.

According to a sixth aspect of the present invention, in the suspension control device for a vehicle equipped with the behavior control device according to the first aspect, the suspension can individually control a transient wheel load on each wheel by changing a damping force of a shock absorber. In such a case, the wheel load of the wheels during the automatic braking is increased by the damping force change control of the shock absorber.

According to a seventh aspect of the present invention, there is provided the suspension control device for a vehicle equipped with the behavior control device according to the sixth aspect, wherein when the wheel is a front wheel during automatic braking, a transient wheel load is increased by increasing a shock absorber damping force of the front wheel. Is raised.

According to an eighth aspect of the present invention, there is provided the suspension control device for a vehicle equipped with the behavior control device according to the sixth aspect, wherein when the wheel is a rear wheel during the automatic braking, the shock absorber damping force of the rear wheel is reduced to make a transition. The wheel load is increased.

[0020]

In the suspension control device according to the first aspect of the invention, while the vehicle behavior control device is controlling the vehicle horizontal surface behavior by the automatic brake, the suspension of the wheel during the automatic brake operation is smaller than during the non-operation of the behavior control. Control suspension to increase wheel load. For this reason, the braking force of the wheel that is being braked by the automatic brake is increased by the load increase, and the behavior control effect can be improved. Moreover, in order to achieve the improvement of the behavior control effect without relying on the increase of the brake fluid pressure, a new problem that the vehicle becomes unstable due to wheel slip on a road surface with a very low friction coefficient such as an icy road. Does not occur.

In the second aspect, the suspension controls the wheel load of each wheel individually according to the braking deceleration to suppress the pitching of the vehicle. However, when the vehicle deceleration occurs with the behavior control by the automatic brake, Also, the suspension performs the same pitch control of the vehicle by controlling the wheel load. By the way, in the pitching control during the behavior control by the automatic brake, the wheel load of the wheel during the automatic brake is increased by changing the wheel load control gain for the braking deceleration.

Therefore, in the second aspect of the present invention, while the vehicle behavior control device is controlling the vehicle horizontal surface behavior by the automatic brake, the wheel load of the wheel during the automatic braking is increased as compared with when the behavior control is not performed. That means
In order to improve the behavior control effect without increasing the brake fluid pressure, the braking force of the wheel that is being braked by the automatic brake is increased by the load increase, and the improvement of the behavior control effect is achieved. Furthermore, there is no new problem that the vehicle becomes unstable due to wheel slip on a road surface having a very low friction coefficient such as an icy road. Moreover, the same object as in the first invention can be achieved only by changing the wheel load control gain in the existing pitching control, which is very advantageous in cost.

According to a third aspect of the present invention, the load control gain for the wheel is changed so that the wheel load on the wheel on the opposite side of the vehicle in the vehicle width direction is reduced by the same load. For this reason, the sum of the wheel load of the wheel whose load has been raised and the wheel load of the wheel on the opposite side in the vehicle width direction is maintained unchanged, and the effect of the second invention is maintained while maintaining the pitching suppression effect. It is very advantageous to be able to achieve it.

According to a fourth aspect of the present invention, a load control gain related to a wheel whose load is increased in the third aspect of the invention is changed so that the wheel load of another wheel on the same side in the vehicle width direction as that of the wheel whose load is increased is reduced by the same load. At the same time, the load control gain for the wheel is changed so that the wheel load on the wheel on the opposite side in the vehicle width direction from the wheel is increased by the same load. For this reason, the sum of the wheel load of the wheel whose load has been raised in the third invention and the wheel load of the other wheel on the same side as the wheel in the vehicle width direction, and the wheels of the front and rear wheels on the opposite side in the vehicle width direction The sum of the loads is maintained the same, and the operation and effect of the second invention can be achieved while maintaining the vehicle body posture in the rolling direction unchanged, which is a great advantage.

In the fifth invention, since the amount of change in the load control gain to be changed in the second invention to the fourth invention is limited, it is possible to prevent an excessively large load control gain from causing an unnatural vehicle posture. .

According to a sixth aspect of the present invention, when the suspension according to the first aspect of the present invention is capable of individually controlling the transient wheel load on each wheel by changing the damping force of the shock absorber, the damping of the shock absorber is provided. The wheel load of the wheels during the automatic braking is increased by the force change control. In this case, the increase in the wheel load can be achieved only during the transition of the vehicle body posture due to the automatic brake, and the same operation and effect as in the first invention can be achieved only in the transitional period. Since the cost is lower than that of the pitching control device, further reduction in cost can be realized.

When the wheel is the front wheel during the automatic braking, the wheel load can be increased by increasing the shock absorber damping force of the front wheel as in the seventh aspect of the present invention. Is a rear wheel, the wheel load can be increased by reducing the shock absorber damping force of the rear wheel as in the eighth invention.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram of a suspension control device according to an embodiment of the present invention, in which 10 is a vehicle body, 11 _FL is a left front wheel, 11 _FR is a right front wheel, 11 _RL is a left rear wheel, and 11 _RR. Indicates the right rear wheel, respectively.

Each of the wheels 11 _FL , 11 _FR , 11 _RL , 11 _RR has a corresponding individual suspension member 1.
2 _FL , 12 _FR , 12 _RL , and 12 _RR are supported on the vehicle body 1 via a vertical stroke so that the suspension members 12 _FL , 12 _FR , 12 _RL , and 12 _RR can correspond to the vehicle body 10. Suspension cylinder 1 that provides a shock absorbing function and a vibration damping function to the vertical movement of wheels
3 _FL , 13 _FR , 13 _RL and 13 _RR are erected. The suspension cylinders 13 _FL , 13 _FR , 13 _RL , and 13 _RR actually extend in a direction perpendicular to the drawing of FIG. 1, but in FIG. 1, they extend along the drawing for convenience of explanation. I showed it.

Each suspension cylinder 13 _FL , 1
3 _FR , 13 _RL and 13 _RR are respectively the cylinder body 13 _a
The piston 13 _b slidably fitted within the piston 13
_b cylinder body 13 of the piston rod 13 _c integral to _a
Of the cylinder body 13
and provided under compression the suspension spring 13 _d between the projecting end and the piston rod 13 _c of _a a configuration that applies a spring force of the cylinder extension direction.

The suspension cylinders 13 _FL , 13 _FR ,
13 _RL and 13 _RR respectively have the projecting end of the piston rod 13 _{c on} the vehicle body 10 and the lower end of the cylinder body 13 _{a on} the suspension members 12 _FL , 12 _FR , 12 _RL and 12 _RR.
To the suspension spring 13
_{By d, the} buffer function required when the corresponding wheel bounces or rebounds is exhibited. Because of this,
The piston 13 _b is observed when its is possible stroke within the cylinder body 13 _a between the front and rear chambers a piston hole 13 _e communicating further piston rod 13 _c due to the stroke moves forward and backward relative to the cylinder body 13 _a the volume change of the piston rod enters volume fraction or exit volume fraction is absorbed by gas spring 13 _f to compensate for the stroke of the piston 13 _b. Then, an orifice 13 _g is inserted into the inlet passage of the gas spring 13 _f , and the vibration resistance required when the corresponding wheel bounces and rebounds is generated by the flow resistance when the hydraulic oil passes through the orifice 13 _g. .

Each suspension cylinder 13 _FL , 1
3 _FR , 13 _RL , 13 _RR internal pressure and therefore each wheel 11 _FL , 1
Pressure control valves 14 _FL , 14 _FR , 14 _RL , 14 _RR for individually controlling the wheel loads of 1 _FR , 11 _RL , 11 _RR are provided, and the output ports of these pressure control valves are connected to the cylinder body 13 _{a of the} corresponding suspension cylinder. Let through. The common pressure supply circuit 16 from the pressure source 15 is connected to the input ports of the pressure control valves 14 _FL , 14 _FR , 14 _RL , and 14 _RR , and the common pressure rejection returning to the pressure source 15 is connected to the drain port. The circuit 17 is connected. Here, the pressure source 15 is the pressure supply circuit 1
The pressure supply circuit 16 is connected to accumulators 18 and 19 for storing the constant pressure.

The pressure control valve 14_FL, 14_FR, 14_RL,
14_RRRespectively represent the circuit 16 and the accumulator 1
The constant hydraulic pressure from 8 and 19 is applied to the cylinder body 13_aRefill within
Or the cylinder body 13_aPressure from circuit 17
The suspension cylinder 13_FL,
13_FR, 13_RL, 13_RRInternal pressure (wheel 11_FL, 11_FR,
11_RL, 11_RRWheel load) with the control current i (i_FL, I
_FR, I_RL, I_RR). This
Here pressure control valve 14_FL, 14_FR, 14_RL, 14_RRControl
Control current i (i_FL, I _FR, I_RL, I_RR) And the suspension
Cylinder 13_FL, 13_FR, 13_RL, 13_RRInternal pressure and
Is in a proportional relationship as illustrated in FIG.
Is the minimum value i_minAnd the maximum value i_maxWhile changing between
Suspension cylinder internal pressure is minimum pressure P _minAnd maximum pressure P
_maxShall be changed between

The pressure control valves 14 _FL , 14 _FR , 14 _RL , 14
The control current _{i FL, i FR, i RL} , i RR to _RR may determine these by the controller 21. Therefore, the controller 21 receives a signal from the longitudinal acceleration sensor 22 for detecting the longitudinal acceleration X _{G of the} vehicle (here, the deceleration is assumed to be positive) and a signal during the operation in which the vehicle behavior control device 23 performs the behavior control. The output is a behavior control signal VDC including which automatic brake fluid pressure is given to which wheel.

Here, the vehicle behavior control device 23 controls the vehicle horizontal surface behavior by automatic braking for each wheel as described in, for example, the above-mentioned Japanese Patent Application Laid-Open No. 7-89427 so that the vehicle horizontal surface behavior is as desired. As is well known, in this embodiment, it is particularly assumed that the left and right front wheels are selectively braked by an automatic brake to control the behavior of the vehicle.

In the above embodiment, the controller 21
Repeats the control program shown in Fig. 3
And execute the pressure control valve 14 as follows._FL, 1
4_FR, 14_RL, 14_RRControl current i_FL, I_FR, I_RL, I
_RRAnd the suspension control that the present invention aims at
Perform. That is, first, in step 31, the sensor 2
Longitudinal acceleration X of the vehicle detected in 2 _GAnd then
In step 32, the behavior control signal VDC is used to control the behavior.
Your right front wheel automatic braking force F_VRIs calculated, and
In step 33, the behavior control signal VDC is used to
Left front wheel automatic braking force F_VLIs calculated.

In step 34, it is determined whether or not the behavior control by the automatic braking of the right front wheel is performed based on whether or not the right front wheel automatic braking force _FVR is generated. In step 35, the left front wheel automatic braking is determined. It is determined whether or not the behavior control by the automatic braking of the left front wheel is being performed based on whether or not the force _FVL is generated. Steps 34 and 35
In the case where the behavior control by the left and right front wheels of the automatic braking is determined to be not executed, in step 36, as in FIG example, as before 4, suspension cylinder pressure change amount of the front and rear wheels relative to the braking deceleration X _G ΔP
(Front wheel load increases, decreasing the load of the rear wheel) to become a kind of α and β, respectively, the front and rear wheel suspension cylinder pressure control gain (front and rear wheel load control gain), respectively for the braking deceleration X _G + K _xG, to -K _xG, it sets the control constant K _Xgl control constants K _XGR and left front and rear wheels of the right front and rear wheels are both the same K _xG.

Next, at step 37, the right front wheel 11
_FRTarget cylinder pressure (target wheel load) P_FR, Left front wheel 1
1_FLTarget cylinder pressure (target wheel load) P_FL, Right rear wheel
11 _RRTarget cylinder pressure (target wheel load) P_RR, Left rear
Wheel 11_RLTarget cylinder pressure (target wheel load) P_RLTo
Each is calculated by the following equation. Here, when a static load is applied,
The internal pressure of the right front wheel suspension cylinder is P_FR0,left
The front wheel suspension cylinder pressure is P_FL0On the right rear wheel
Suspension cylinder pressure is P_RR0, Left rear wheel suspension
The internal pressure of the cylinder is P_RL0It is assumed that P_FR= P_FR0+ K_xGR・ X_G... (1) P_FL= P_FL0+ K_xGL・ X_G... (2) P_RR= P_RR0-K_xGR・ X_G... (3) P_RL= P_RL0-K_xGL・ X_G... (4)

In the next step 38, as described above,
Obtained right front wheel target cylinder internal pressure P_FR, Left front wheel target
Da internal pressure P_FL, Right rear wheel target cylinder pressure P_RR, Left rear wheel target
Cylinder pressure P_RLFor each of the right front wheels
Pressure control valve 14_FRControl current i_FR, Pressure control for front left wheel
Valve 14_FLControl current i_FL, Right rear wheel pressure control valve 14 _RR
Control current i_RR, And pressure control valve 14 for the left rear wheel_RLWhat
Control current_RLBy a map search as illustrated in FIG.
And output these to the corresponding pressure control valve to
Of the suspension cylinder pressure (wheel load)
Set the standard.

As described above, in steps 34 and 35,
If the behavior control by automatic braking of the front wheels is not performed
During the determination, the right front wheel 11_FRAnd left front wheel 11_FLSus of
Fig. 7 shows the internal pressure (wheel load) of the pension cylinder.
As indicated by the dashed underline, the braking deceleration
X_GAnd rises as shown by α in FIG.
Wheel 11_RRAnd left rear wheel 11_RLSuspension cylinder
The internal pressure (wheel load) is underlined in broken line in FIG.
As shown in the figure, the braking deceleration X _GOf FIG. 4 according to
As shown by. Because of this, braking deceleration X_G
4 is suppressed, and in addition, FIG.
As before, α and β are not enough to make pitching 0
To a small extent, so when the behavior control is not
Is suitable pitching while producing a suitable braking feeling as before
This can produce an effect of suppressing rush.

By the way, while it is determined in steps 34 and 35 that the behavior control by the automatic braking of the left and right front wheels is being performed, the suspension cylinder internal pressure (wheel load) of each wheel is controlled as follows. First, the operation when it is determined in step 34 that the behavior control by the automatic braking of the right front wheel is being performed will be described.

[0042] In step 39 this case, for example, as in FIG. 5, the right front and rear wheels 11 relative to the brake deceleration X _G
FR , 11 _RR suspension cylinder pressure change ΔP
(The amount of increase in the cylinder pressure of the front wheel and the amount of decrease of the cylinder pressure of the rear wheel) become α _FR and β _RR indicated by broken _lines having a gradient larger by ΔK _{× G} than α and β shown in FIG.
Braking deceleration X right front and rear with respect to _G-wheel suspension cylinder pressure control gain (right front and rear wheel load control gain), respectively _{+ (K xG + ΔK xG)} , - (K xG + ΔK xG) to the control variable of the right front and rear wheels K _xGR to (K _xG
+ ΔK _xG ), and the left and right front wheels 11 _FL , 11 _{FL with} respect to the braking deceleration X _G as shown in FIG.
_{The RL} suspension cylinder pressure change amount ΔP (the front wheel cylinder pressure increase amount and the rear wheel cylinder pressure decrease amount) is indicated by a one-dot chain line having a gradient smaller by ΔK _{× G} than α and β shown in FIG. 4, respectively. alpha _FL, beta _RL become so, the left front and rear wheels suspension cylinder pressure control gain for the braking deceleration X _G a (left front and rear wheel load control gain) respectively _{+ (K xG -ΔK xG),} - (K xG -ΔK xG) In order to achieve the above, the control constants K _xGL for the left and right front wheels are respectively set to (K _xG −Δ
K _xG ).

[0043] At step 37 and 38, by performing the same processing as described above using a control constant K _Xgl control constants K _{xG R} and the left front and rear wheels of the right front and rear wheels obtained as described above, each wheel Is set to the target value calculated in step 37,
The behavior control in performed by applying the automatic braking force F _VR in FIG. 7 to the right front wheel 11 _FR is possible to set the control constants K _Xgl control constants K _XGR and left front and rear wheels of the right front and rear wheels, respectively, as described above Therefore, the following operation and effect can be obtained. That is, the control constant K _XGR, according to the above setting of the K _Xgl, as shown denoted by the solid line underline in Figure 7, the suspension cylinder pressure of the right front wheel 11 _FR (wheel load) when the pitching control braking deceleration X than α
_G is increased by (ΔK _xG × X _G ) (α _{FR in} FIG. 5).
See), is reduced by the suspension cylinder pressure of the left front wheel 11 _FL (wheel load) corresponding to the braking deceleration X _G than α when the pitching control (ΔK _xG × X _G) (Fig. 5
See alpha _FL), it is reduced by the suspension cylinder pressure of the right rear wheel 11 _RR (wheel load) corresponding to the braking deceleration X _G than β during the pitching control (ΔK _xG × X _G) (in Fig. 5 see beta _RR), is increased by the suspension cylinder pressure of the left rear wheel 11 _RL (wheel load) corresponding to the braking deceleration X _G than beta during the pitching control (ΔK _xG × X _G) (in Fig. 5 β _RL ).

As described above, during the behavior control by the automatic braking of the right front wheel _11FR (refer to _{FVR in} FIG. 7), the right front wheel 1FR
Becomes the 1 _FR suspension cylinder pressure (wheel load) is increased, correspondingly, with the automatic braking force of the right front wheel 11 _FR from F _VR of Figure 7 is increased to F _VR ', to improve the behavior control effect be able to. Moreover, in order to achieve the improvement of the behavior control effect without relying on the increase of the brake fluid pressure, a new problem that the vehicle becomes unstable due to wheel slip on a road surface with a very low friction coefficient such as an icy road. Does not occur.

Further, in this embodiment, the improvement of the behavior control effect can be realized only by changing the suspension cylinder internal pressure (wheel load) control gain in the existing pitching control, which is very advantageous in cost. If the change of the suspension cylinder pressure (wheel load) control gain is performed as in the present embodiment, the suspension of the right front wheel _11FR is apparent as shown by the solid underline in FIG. cylinder pressure (wheel load) increase amount ([Delta] K _xG × X _G) by the same amount as the left front wheel 11 _FL suspension cylinder pressure (wheel load)
Is reduced, the suspension cylinder internal pressure (wheel load) of the right rear wheel 11 _RR is reduced by the same amount as the amount (ΔK _xG × X _G ), and the suspension cylinder internal pressure (wheel load) of the left rear wheel 11 _RL is reduced. Is raised.

Therefore, the sum of the internal pressures of the suspension cylinders (wheel loads) related to the left and right front wheels and the sum of the internal pressures of the suspension cylinders (wheel loads) related to the right and left rear wheels are maintained the same as those during the pitching control. As a result, the pitching suppression effect described above with reference to FIG. In addition, the sum of the suspension cylinder internal pressure (wheel load) related to the right and left front wheels and the sum of the suspension cylinder internal pressure (wheel load) related to the left and right wheels are maintained at the same level as during the pitching control. No change in the wheel load sum occurs, and no change in the vehicle body attitude in the rolling direction occurs. Therefore, in the present embodiment, the above-described behavior control effect can be improved without any change in the posture of the vehicle body in the pitching direction and the rolling direction.

When it is determined in step 35 of FIG. 3 that the behavior control by the left front wheel is automatically controlled, the control constants _KxGR for the right and left front wheels are reversed in step 40, as _{opposed to} step 39. To (K _xG −
ΔK _xG ) and the control constant K for the left and right front wheels.
After setting _xGL to (K _xG + ΔK _xG ), the control proceeds to steps 37 and 38. In this case, in the suspension cylinder pressure change amount ΔP (wheel load change amount) characteristic of each wheel, the characteristic α _FR relating to the right front wheel and the characteristic α _FL relating to the left front wheel in FIG. The characteristic β _RR is replaced with the characteristic β _RL relating to the left rear wheel.

As a result, a solid underline is shown in FIG.
, The left front wheel 11 _FLSuspension
Cylinder pressure (wheel load) is α at the time of the pitching control.
Braking deceleration X_G(ΔK_xG× X_G) Only increase
Enlarged, right front wheel 11_FRSuspension cylinder pressure
(Wheel load) is smaller than α during the pitching control.
Speed X_G(ΔK_xG× X_G) Just dropped, left rear
Wheel 11_RLSuspension cylinder pressure (wheel load)
Braking deceleration X than β during the pitching control_GAccording to
(ΔK_xG× X_G), The right rear wheel 11_RRSus of
The internal pressure of the pension cylinder (wheel load)
Braking deceleration X than β during control_G(ΔK_xG× X
_G).

[0049] Thus, even during the behavior control by the automatic braking of left front wheel 11 _FL, will be the suspension cylinder pressure of the left front wheel 11 _FL (wheel load) is increased, the automatic braking of that amount, the left front wheel 11 _FL The force can be increased to improve the behavior control effect. Also in this case, the sum of the suspension cylinder internal pressures (wheel loads) related to the left and right front wheels and the sum of the suspension cylinder internal pressures (wheel loads) related to the left and right rear wheels are maintained at the same level as during the pitching control. , FIG.
And the sum of the internal pressure of the suspension cylinder (wheel load) related to the right and left front wheels and the total of the internal pressure of the suspension cylinder (wheel load) related to the left and right front wheels is also the same. The same is maintained as in the pitching control, and as a result, there is no change in the sum of the wheel loads between the left and right sides, and no change in the body posture in the rolling direction occurs.

The change amount ΔK _xG (see FIGS. 5 and 7) of the control gain of the suspension cylinder pressure (wheel load) depends on the automatic braking forces F _VL and F _VR of the left and right front wheels as shown in FIG. It is preferable to reliably increase the behavior control effect, but in any case, an upper limit is set to the control gain change amount ΔK _xG as shown in FIG. Needless to say, it is better to prevent the vehicle posture from becoming unnatural.

In the above embodiment, the vehicle behavior control device 23 shown in FIG. 1 has been described as performing vehicle behavior control by selectively braking only the left and right front wheels by automatic braking. The same concept is applied to the case of performing selective automatic braking of the left and right rear wheels, that is, the load of the wheel during automatic braking is increased, and the wheel load of the wheel on the opposite side in the vehicle width direction is the same. The wheel load of the other wheel on the same side as the wheel whose load has been raised is reduced by the same amount as that of the wheel whose load has been raised is reduced by the same load, and the wheel load of the wheel on the opposite side of the vehicle width direction from the wheel is the same. By changing the control gain of the suspension cylinder internal pressure (wheel load) related to each wheel so that it is raised by the load, the same function and effect can be achieved. It is a matter of course.

[0052] Although not shown, a like suspension changing the opening of the orifice 13 _g in the inlet passage of gas spring 13 _f shown in FIG. 1, when those capable of controlling the damping force of the shock absorber In the transitional period in which the vehicle body generates a pitching movement called nose dive by automatic braking for behavior control, the wheel load on each wheel can be adjusted by the damping force control, so the shock absorber damping force of each wheel is reduced. By changing them individually, the wheel load of the wheels during the automatic braking can be increased, and the behavior control effect can be improved as in the above embodiment. In this case, the increase of the wheel load is only during the change of the vehicle body posture (pitching motion) due to the automatic brake, and the improvement of the behavior control effect can be expected only in the transitional period. Since the cost is lower than that of the pitching control device, further cost reduction can be realized.

Here, the change in the posture of the vehicle body due to the automatic braking is a nose dive, and the shock absorber of the front wheel suspension performs a contraction operation, and the shock absorber of the rear wheel suspension performs an extension operation.
When the wheel is a front wheel during automatic braking, it is possible to increase the wheel load by increasing the shock absorber damping force of the front wheel, and when the wheel is a rear wheel during automatic braking, An increase in wheel load can be realized by reducing the shock absorber damping force of the wheel.

[Brief description of the drawings]

FIG. 1 is a suspension control system diagram showing a suspension control device of a vehicle equipped with a behavior control device according to an embodiment of the present invention.

FIG. 2 is a control characteristic diagram relating to a pressure control valve for internal pressure of a suspension cylinder in the suspension control system.

FIG. 3 is a flowchart showing a suspension cylinder internal pressure control program executed by a controller in the embodiment.

FIG. 4 is a control characteristic diagram of suspension cylinder internal pressure change amount control performed during non-operation of behavior control in the embodiment.

FIG. 5 is a control characteristic diagram of suspension cylinder internal pressure change amount control performed during behavior control by automatic braking of the right front wheel in the embodiment.

FIG. 6 is a change characteristic diagram of a suspension cylinder internal pressure control gain change amount set in the embodiment.

FIG. 7 is a schematic plan view of the vehicle, showing a change in suspension cylinder internal pressure of each wheel in a state in which behavior control is not performed and in a behavior control.

[Explanation of symbols]

10 Body 11 _FL left front wheel 11 _FR right front wheel 11 _RL left rear wheel 11 _RR right rear wheel 12 _FL left front wheel suspension member 12 _FR right front wheel suspension member 12 _RL left rear wheel suspension member 12 _RR right rear wheel suspension member 13 _FL left front wheel Suspension cylinder 13 _FR Right front wheel suspension cylinder 13 _RL Left rear wheel suspension cylinder 13 _RR Right rear wheel suspension cylinder 14 _FL Pressure control valve for left front wheel suspension cylinder 14 _FR Pressure control valve for right front wheel suspension cylinder 14 _{RL For} left rear wheel suspension cylinder Pressure control valve 14 _RR Pressure control valve for right rear wheel suspension cylinder 15 Hydraulic source 16 Pressure supply circuit 17 Pressure elimination circuit 18 Accumulator 19 Accumulator 21 Controller 22 Front-rear acceleration sensor 23 Vehicle behavior control device

Claims (8)

[Claims] 1. A vehicle having a vehicle behavior control device that controls a vehicle horizontal surface behavior by an automatic brake, wherein a vehicle is suspended by a suspension capable of individually controlling a wheel load on each wheel. The vehicle suspension control apparatus according to claim 1, wherein the control unit controls the suspension so as to increase a wheel load of the wheel during the automatic braking when the vehicle behavior is controlled by the control of the vehicle. 2. The wheel load with respect to the braking deceleration according to claim 1, wherein the suspension controls the wheel load of each wheel individually in accordance with the braking deceleration to suppress the pitching of the vehicle. A suspension control device for a vehicle equipped with a behavior control device, wherein the control gain is changed to increase the wheel load of the wheel during automatic braking. 3. The load control gain according to claim 2, wherein the load control gain related to the wheel whose load has been raised is reduced by the same load as that of the wheel on the opposite side of the vehicle in the vehicle width direction. A suspension control device for a vehicle equipped with a behavior control device. 4. The load control gain according to claim 3, wherein a wheel load of another wheel on the same side in the vehicle width direction as the wheel whose load has been raised is reduced by the same load. A suspension for a vehicle equipped with a behavior control device, wherein a load control gain related to the wheel is changed so that a wheel load of a wheel on the opposite side of the vehicle width direction is increased by the same load. Control device. 5. A suspension control device for a vehicle equipped with a behavior control device according to claim 2, wherein a limit is set to a change amount of the load control gain related to each wheel. 6. The shock absorber according to claim 1, wherein the suspension is capable of individually controlling a transient wheel load on each wheel by changing a damping force of the shock absorber. A suspension control device for a vehicle equipped with a behavior control device, wherein the wheel load of the wheel during automatic braking is increased by control. 7. The behavior control according to claim 6, wherein when the wheel is a front wheel during automatic braking, the shock absorber damping force of the front wheel is increased to increase the transient wheel load. Suspension control device for equipment-equipped vehicles. 8. The vehicle according to claim 6, wherein when the wheel is a rear wheel during automatic braking, a shock absorber damping force of the rear wheel is reduced to increase a transient wheel load. A suspension control device for vehicles equipped with a behavior control device.