JPS63188512A - Vehicle attitude control device - Google Patents

Abstract

PURPOSE:To obtain a suitable turning characteristic by regulating desired twist amounts of front and rear wheel side stabilizers in accordance with the turning condition of a vehicle, and by making the desired twist amounts different from each other in accordance with the turning condition of the vehicle. CONSTITUTION:Front and rear wheel side regulating means M1, M2 regulates, in accordance with external instructions, the twist amounts of front and rear wheel side stabilizers which couple both nonsuspended members of front and rear wheels on both right and left sides of a vehicle. Further, a control means M4 delivers, to the regulating means M1, M2, instructions for setting the twist amounts of the front and rear wheel side stabilizers to desired twist amounts corresponding to the widthwise acceleration of the vehicle which is determined in accordance with a signal from a means M3 for generating a vehicle turning condition indicating signal. In this arrangement, there is provided a changing means for changing the desired twist amounts of the front and rear wheel side stabilizers determined by the control means M4 so that both desired values are different from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION [Field of Industrial Application] The present invention relates to a heavy-duty attitude control device that is effective for changing turning characteristics when a vehicle is turning.

[Prior Art] Conventionally, the unsprung members of the left and right wheels of a vehicle are connected by a stabilizer (anti-roll bar) to coordinate the independent movements of the left and right wheels, thereby improving the stability of the vehicle when the vehicle is turning. The technology to reduce tilting and shaking (rolling) is known. That is, when the left and right wheels are at the same suspension position, such as when driving straight on a flat road, the stabilizer does not twist, and the movements of the left and right wheels are independent without being influenced by the stabilizer. However, when one of the left and right wheels passes over a protrusion or when the vehicle is turning, the suspension positions of the left and right wheels are significantly different and the torsion bar of the stabilizer is twisted, and as a result, due to the reaction of the torsion bar,
A restoring force acts in a direction that cancels out this twisting, and moves in a direction that equalizes the suspension positions of the left and right wheels, suppressing rolling.

Incidentally, from the viewpoint of the posture stability of the vehicle, the ability of the wheels to follow the road surface is important when the vehicle is traveling straight, and the rolling suppression function is important when the vehicle is turning.

Here, in order to improve road followability, it is preferable that the restoring force generated by the stabilizer is small, and on the other hand, in order to improve the rolling suppressing function, it is preferable that the restoring force is large.

However, in the past, the torsional rigidity of the stabilizer's torsion bar was constant, so it was difficult to achieve both road tracking performance and rolling suppression function, and the torsional rigidity had to be set at an appropriate design value as a compromise. Ta. As a countermeasure to this problem, for example, the 1-ton dual-use attitude control system.
(Japanese Unexamined Patent Publication No. 61-14'6612) etc. have been proposed. In other words, the control corresponding to the roll ω of the vehicle is calculated based on the running speed and the steering angle of the vehicle, and the This is a technology that changes the torsional rigidity of the stabilizer.

[Problems to be Solved by the Invention] In order to improve the overall turning performance of a vehicle, in addition to reducing roll suspension during turning, it is necessary to adjust the turning characteristics of the vehicle appropriately according to the turning state. It is extremely important to adjust the For example, when turning at low or medium speeds, it is desirable to shift the vehicle to oversteer characteristics rather than the predetermined basic turning characteristics specific to the vehicle, and on the other hand, when turning at high speeds, it is desirable to shift the basic turning characteristics to understeer characteristics.

However, in the above-mentioned conventional technology, the relative difference between the torsional rigidity of the front wheel stabilizer and the torsional rigidity of the rear wheel stabilizer is always constant when the vehicle is turning. Therefore, the turning characteristics of the vehicle remained at the basic turning characteristics regardless of the turning state. As described above, there is a problem in that no consideration is given to adjusting the turning characteristics of the vehicle in accordance with changes in the turning state.

In general, the basic turning characteristics of a vehicle are determined by the effects of the basic turning characteristics on the driver, such as the mental burden placed on the driver when changing lanes, the frequency of corrective steering when driving straight at high speed in strong winds, and the influence of crosswinds. In consideration of the effect of the so-called counter-steering in such a case, the steering wheel is set to be slightly closer to the angle steering characteristic than the neural steering characteristic. For this reason, if the basic turning characteristics are maintained regardless of the turning state, for example, when turning at low or medium speeds, it will be difficult to quickly transition to turning due to insufficient steering angle, while when turning at high speeds, it will be difficult to transition quickly to turning. On the other hand, an excessive steering angle also caused a problem in that it became difficult to transition to stable turning.

Furthermore, if the steering wheel is operated with the same steering feel all the time, the vehicle will behave differently as the turning condition changes due to the reasons mentioned above.
Frequent corrective steering is required. In this way, there is also the problem of placing an excessive burden on the driver.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heavy-duty attitude control device that suppresses rolling when a vehicle is turning and can suitably change the turning characteristics of the vehicle depending on the turning state.

Structure of the Invention [Means for Solving the Problems] The present invention, which has been made to solve the above problems, provides a front wheel side stabilizer that connects both unsprung members of the left and right front wheels of a vehicle, as illustrated in FIG. After adjusting the torsion limit of the front wheel side adjusting means M1 according to an external command, and the torsion limit of the rear wheel stabilizer that connects the unsprung members of the left and right rear wheels of the vehicle according to an external command. a wheel side adjusting means M2; a turning state signal generating means M3 for generating a turning state signal according to the turning state of the vehicle; and a turning state signal generating means for adjusting the amount of torsion of the front wheel stabilizer and the rear wheel stabilizer. a control means M4 that gives a command to the front wheel adjustment means M1 and the rear wheel adjustment means M2 to set the target torsion maximum corresponding to the vehicle widthwise acceleration of the vehicle determined based on the turning state signal generated by M3; In the vehicle attitude control system, the target twist amount of the front wheel stabilizer and the target amount of the rear wheel stabilizer determined by the control means M4 are further determined according to the turning state signal generated by the turning state signal generating means M3. The gist of the present invention is a vehicle attitude control device characterized by comprising a changing means M5 for changing the twist star to be different.

The front wheel side adjustment means M1 is the twisting of the front wheel side stabilizer.
is adjusted according to instructions from the outside. For example, a hydraulic cylinder is attached to either the part of the front wheel stabilizer that transmits and receives torsional force and an unsprung member of at least one of the left and right front wheels, and a hydraulic cylinder is attached to the other and is movably engaged with the hydraulic cylinder. This can be realized by a hydraulic circuit that supplies and discharges pressurized fluid between the cylinder L and the hydraulic pressure source. Further, for example, the front wheel stabilizer divided into two parts at the torsion portion may be configured by a hydraulic actuator that can rotate forward and reverse around the longitudinal axis of the front wheel stabilizer.

The rear wheel adjustment means M2 adjusts the amount of twist of the rear wheel stabilizer according to an external command. For example, this can be realized by interposing the above-described hydraulic cylinder and piston between the rear wheel stabilizer and the unsprung member of at least one of the left and right rear wheels, and roughly providing a hydraulic circuit. Further, for example, the rear wheel stabilizer divided into two parts at the torsion portion may be configured to have an upper hydraulic actuator disposed thereon.

The turning state signal generating means M3 generates a turning state signal according to the turning state of the vehicle.

For example, it can be realized by a vehicle speed sensor that generates a speed signal that corresponds to the traveling speed of the vehicle and a steering sensor that generates a steering signal that corresponds to the steering angle.

Alternatively, for example, it may be constructed from a vehicle width direction acceleration sensor, a yaw rate sensor, etc. disposed near the center of gravity of the vehicle.

The control means M4 provides a command to set the torsion of the front wheel side and rear wheel side stabilizers to a target torsional calm corresponding to the vehicle width direction acceleration determined based on the turning state signal. For example, it can be realized by an arithmetic expression or map that calculates the target torsion base from the vehicle speed and the vehicle width direction acceleration obtained by dividing the square value of the vehicle speed by the turning radius of the vehicle determined from the steering angle. Alternatively, for example, it may be configured by an arithmetic expression or a map for calculating the target twist amount from the vehicle speed and the steering angle, or the vehicle speed, the steering angle, and the steering angular velocity.

The changing means M5 changes the target torsion maximum of the front wheel stabilizer and the target torsion maximum of the rear wheel stabilizer determined by the control means M4 in accordance with the turning state signal. For example, when a speed signal is generated as a turning state signal, the target torsion bar of the rear wheel stabilizer may be changed to be greater than the target torsion d of the front wheel stabilizer as the speed signal decreases. . Also, for example,
When a speed signal is generated as the turning state signal, as the speed signal increases, the target twist maximum of the front wheel stabilizer may be changed to be larger than the target twist amount of the rear wheel stabilizer. Such a change in the target torsional suspension can be realized, for example, by using a map or an arithmetic expression that defines the relationship between the vehicle speed, the acceleration in the vehicle width direction, and the target torsional maximum.

The control means M4 and the change means M5 can be realized, for example, by independent discrete logic circuits.

For example, in addition to the well-known CPU, ROM, RAM
and other peripheral circuit elements as a logical arithmetic circuit, and according to a predetermined processing procedure, both means M4. M5 may also be implemented.

C Effect 1 As illustrated in FIG. 1, the vehicle attitude control device of the present invention provides front wheel stabilization! The control means M4 adjusts the front wheel side by giving a command to set the torsion of the a and rear wheel side stabilizers to a target amount of torsion corresponding to the vehicle width direction acceleration determined based on the turning state signal generated by the turning state signal generating means M3. When applying this to the means M1 and the rear wheel adjusting means M2, the changing means M5 changes the target torsional suspension of the front wheel stabilizer determined by the controlling means M4 in accordance with the turning state signal generated by the turning state signal generating means M3. It works to change the target twist of the rear wheel stabilizer to be different.

Here, the behavior of a four-wheeled vehicle during turning will be explained. As shown in Figure 2 (1), four-wheeled vehicles generally ignore the centrifugal force CF acting on the vehicle center of gravity CG when turning at very low speeds (vehicle speed V is close to O). Front left and right wheels F W L.

FWR1 left and right rear wheels RWI and RWR turn around the intersection MO of four straight lines (indicated by dashed lines in the figure) perpendicular to each rolling direction. Therefore, the distance between the vehicle center of gravity CG and the above-mentioned intersection MO (indicated by the two-dot chain line in the figure) is
The turning radius is R○ at extremely low speed. On the other hand, during turning during normal driving, the centrifugal force CF acting on the vehicle center of gravity CG can be expressed as shown in the following equation (1).

CF=mxV2/R・ (1) However, m...Vehicle quality maximum ■...Vehicle speed R...Turning radius At this time, left and right front wheels FWL, FWR1 left and right rear wheels RW
L and RWR are wheel sideslip angle αFL, respectively.

αFR, αRL, αRR are generated, and the wheel sideslip angle αF
L, αFR, αRL, and αRR generate cornering forces on the road surface and the ground contact portion of each wheel. This j
4, each wheel FWL, FWR.

The resultant force of the cornering forces generated at RWL and RWR becomes a centripetal force that balances the centrifugal force CF.

In this case, the four-wheeled vehicle turns around the intersection M of four straight lines (indicated by broken lines in the figure) perpendicular to the traveling direction of the four-wheeled vehicle. Therefore, the distance between the vehicle center of gravity CG and the above-mentioned intersection M (indicated by a solid line in the figure) becomes the turning radius R during normal driving.

The rate of change of the turning radius RO during normal running with respect to the turning radius RO during extremely low speed is expressed by the following equation (2). This tendency is observed when the acceleration in the vehicle width direction is 0.3 [g] (q
This is particularly noticeable when the gravitational acceleration is 9.8 [m/sec] or less.

R/RO=1+KhxV2...(
2) However, the value Kh is a stability factor (Stability Fact).

r) The relationship of the above formula (2) is shown in FIG. 2 (2). As shown in the figure, the stability factor Kh corresponds to the slope of the straight line expressed by the above equation (2). Here, the turning characteristics of a four-wheeled vehicle are the steering characteristics, when the value of the stability factor Kh is positive (marked with a broken line in the figure);
When the value of the stability factor Kh is ◯, the vehicle has neutral steering characteristics (indicated by a solid line in the figure), and when the value of the stability factor Kh is negative, the vehicle has oversteer characteristics.

By transforming the above equation (2), the following equation (3) is obtained.

Kh= (mx (CPRxL2-CPFxL 1))
/ (CPFxCPRxL2) ... (3)
However, rn... Mass of vehicle CPR... Rear wheel cornering power L2... Distance between rear wheel axle and vehicle hand center CG CPF...
- Front wheel cornering power L1...Distance L between the front wheel axle and the vehicle center of gravity CG...Vehicle wheelbase Note that the cornering force described above is the product of the cornering power described above and the sideslip angle described above.

By the way, the behavior when the vehicle is turning left is explained in the third section.
This will be explained based on Figure (1). Note that this figure shows the front part of the four-wheeled vehicle. As shown in the figure, during a left turn, centrifugal force CF acting on the vehicle center of gravity CG causes the vehicle width outside the turn (right wheel WR
), the wheel load on the turning wheel decreases by a predetermined minimum, while the wheel load on the non-turning vehicle width increases by a predetermined amount. During this load movement, for example, the stabilizer STB
If the torsional rigidity of the vehicle is low, the roll angle of the vehicle will be a large angle φ1, but the amount of wheel load movement will be a relatively small value △
It becomes W'1. On the other hand, if the torsional rigidity of the stabilizer STB is high, the roll angle of the vehicle will be an angle φ2 smaller than the above angle φ1, or the amount of movement of the wheel load will be the above value ΔW1.
The larger value ΔW2 is obtained. Considering this phenomenon in a four-wheeled vehicle, for example, if the torsional rigidity of the front wheel stabilizer is increased, the load transferred to the front wheel side outside the turning width will increase, and the load transferred to the rear wheel side outside turning width will decrease; When the torsional rigidity of the stabilizer is reduced, the load transferred to the front wheel side outside the turning width of the vehicle decreases, and the load transferred to the rear wheel side outside the turning width of the vehicle increases.

The relationship between the above wheel load and cornering power is shown in Figure 3 (
It exhibits upwardly convex nonlinear characteristics as shown in 2). Therefore, when the torsional rigidity of the stabilizer STB is low (the amount of movement of the wheel load is a small value △W1), the cornering power CP
As shown in the following equation (4), L1+CPR1 is the cornering power CP 12 + when the torsional rigidity of the stabilizer STB is high (when the amount of wheel load movement is too large ΔW2>)
It becomes larger than CP R2.

CPL1+CPR1>CPL2〇PR2...(4)
Therefore, for example, if you are in a four-wheeled vehicle and the torsional rigidity of the front wheel stabilizer is made relatively higher than the torsional rigidity of the rear wheel stabilizer, the front wheel cornering power CPF will be Since the power CPR is smaller than the power CPR, the value of the stability factor Kh obtained from the above equation (3) increases, and the turning characteristics shift to the side where the understeer characteristics become stronger, as shown in FIG. 2 (2>).

On the other hand, if the torsional rigidity of the rear wheel stabilizer is made relatively higher than the torsional rigidity of the front wheel stabilizer, the rear wheel cornering power CPR becomes smaller than the front wheel cornering power CPF, as in equation (4) above. The above formula (3
), the value of stability factor Kh decreases,
As shown in FIG. 2 (2), the understeer characteristic becomes weaker or the turning characteristic shifts to the oversteer characteristic side.

Therefore, the vehicle attitude control device of the present invention suppresses rolling by changing the target torsion opening of the front wheel stabilizer and the target torsion opening of the rear wheel stabilizer when the vehicle is turning. It works to achieve turning characteristics. The technical problems of the present invention are solved by each component of the present invention acting as described above.

[Example] Next, a preferred example of the present invention will be described in detail based on the drawings. FIG. 4 shows a system configuration of a vehicle attitude control device that is an embodiment of the present invention.

As shown in the figure, the vehicle attitude control device 1 includes a front wheel stabilizer device 2, a rear wheel stabilizer device 3, a hydraulic circuit 4, and an electronic control device (hereinafter simply referred to as E) that controls these.
It is called CU. ) It consists of 5 parts.

In the front wheel stabilizer device 2 , a left front wheel 6 is supported by a vehicle body 9 by a left front wheel shock absorber 7 and a left front wheel lower arm 8 . Further, the right front wheel 10 is supported by the vehicle body 9 by a right front wheel shock absorber 11 and a right front wheel lower arm 12.

Further, the torsion portion of the front wheel stabilizer bar 13 is rotatably supported by the vehicle body 9 by bearings 14 and 15 fixed to the vehicle body 9 with bolts or the like.

One end portion 13a of the front wheel stabilizer bar 13 is connected to a sprung portion of the right front wheel shock absorber 11 via a front wheel cylinder unit 16 whose connection distance can be adjusted.
The connection distance between the one end 13a of the front wheel stabilizer bar 13 and the lower part of the spring of the right front wheel shock absorber 11 is such that the front wheel side silling unit 16 receives pressurized oil from the hydraulic circuit 4 under the control of the ECU 3. It can be adjusted by expanding and contracting. Above front wheel side stabilizer bar 13
The other end 13b is attached to the lower portion of the spring of the front wheel shock absorber 7 via a dummy rod 17. Also,
A steering wheel 18 is used to steer the vehicle.
A steering mechanism 19 is also provided to change the direction of the left and right front wheels 6° 10 in accordance with the operation.

On the other hand, in the rear wheel stabilizer device 3, the left rear wheel 20 includes a left rear wheel shock absorber 21 and a left rear wheel lower arm 2.
2 is supported by the vehicle body 9.

Further, the right rear wheel 23 is supported by the vehicle body 9 by a right rear wheel shock absorber 24 and a right rear wheel lower arm 25.

Roughly speaking, the torsion portion of the rear wheel stabilizer bar 26 is rotatably supported by the vehicle body 9 by bearings 27 and 28 fixed to the vehicle body 9 with bolts or the like. One end portion 26a of the rear wheel stabilizer bar 26 is coupled to a sprung portion of the right rear wheel shock absorber 24 via a rear wheel cylinder unit 29 whose connection distance can be adjusted. The connection distance between 26a and the lower part of the spring of the right rear wheel shock absorber 24 can be adjusted by expanding and contracting the cylinder unit 29 on the rear wheel side that receives pressure oil from the hydraulic circuit 4 under the control of the ECU 3. It has become. The other end 26b of the rear wheel stabilizer bar 26 is connected to the left rear wheel shock absorber 2 via a dummy rod 30.
It is installed in the lower part of the spring.

The vehicle attitude control device 1 includes a vehicle speed sensor 31 that detects the running speed of the vehicle, a steering sensor 32 that detects the steering angle, and a front wheel that detects the connection distance (stroke) extended and contracted by the cylinder unit 16 on the front wheel side. A stroke sensor 34 on the side of the rear wheel is provided for detecting the connecting distance (stroke amount) of expansion and contraction by the side stroke sensor 33 and the cylinder units 1 to 29 on the rear wheel side. Signals from each of the above sensors are input to the ECU 3, which controls the front wheel stabilizer device 2, the rear wheel stabilizer device 3, and the hydraulic circuit 4.

Since the structure of the above cylinder unit 16.29 is the same,
The cylinder unit 16 will be explained as an example. As shown in FIG. 5, the cylinder unit 16 includes a cylinder 41
A piston 42F is slidably fitted into the cylinder 41F, and the piston 42F divides the inside of the cylinder 41F into an upper chamber 45F having a port 43F and a royal chamber 46F having ports 1-44F.

Further, a rod 47F is fixed to the piston 42F.

As shown in FIG. 6, in the front wheel side cylinder unit 16, a rod 47F is attached to the lower part of the right front wheel shock absorber 11 arranged in parallel with the right front wheel coil spring 11a, and a cylinder 41F is attached to the front wheel side stabilizer bar 13. It is coupled to one end portion 13a. Therefore, the front wheel stabilizer device 2 is configured to change the torsional rigidity of the front wheel stabilizer bar 13 by moving the piston 42F of the cylinder unit 16 over a predetermined stroke amount. Note that the stroke position of the piston 42F (shown in FIG. 5) of the cylinder unit 16 is detected by the stroke sensor 33 described above. Furthermore, the rear wheel stabilizer device 3 has a similar configuration.

The above front and rear wheel side cylinder units 16.29
As shown in Figure 7 of the vehicle, is operated by pressure oil supplied from the hydraulic circuit 4 under the control of the ECU 3.

The hydraulic circuit 4 includes a front-wheel hydraulic system 4a that supplies pressure oil to the front-wheel cylinder unit 16 and a rear-wheel hydraulic system 4b that supplies pressure oil to the rear-wheel cylinder unit 29. Since the circuit configurations of both the hydraulic systems 4a and 4b are similar, the front wheel hydraulic system 4a will be described as an example.

The front wheel side hydraulic system 4a sucks hydraulic oil from a hydraulic pump 52F driven by an engine 50 via a power transmission mechanism 51 and a 4-arbor 53F, and connects a pipe 54F and a front wheel side directional control valve (4 points, 3 positions). solenoid valve) 55F, and pipe 5
Pressure oil is supplied to the cylinder unit 16 via 6F and 57F. The upper chamber 45F and the royal chamber 46F of the cylinder unit 16 communicate with each other via a front wheel side linear solenoid valve (electromagnetic valve for flow control) 59F. The front wheel side direction control valve 55F is in a neutral position 55Fa, an extended position 55Fb, and a retracted position 55FC according to the control signal from the EC1J5.
On the other hand, the front wheel side linear solenoid valve 59F has an opening degree according to the duty ratio control signal from the ECU 3.

The above ECU 3 includes a CPU 5a, a ROM 5b, and a RAM 5C.
It is configured as a logic operation circuit centering on the common bus 5d.
It is connected to the input section 5e and the output section 5f via the input section 5e, and performs input/output with the outside. The signals from each of the sensors described above are input to the CPU 5a via the input section 5e.
The PU5a is connected to the front wheel side direction control valve 55 via the output section 5f.
F, a control signal is output to the front wheel side linear solenoid valve 59F, the rear wheel side directional control valve 55R, and the rear wheel side linear solenoid valve 59R.

The vehicle attitude control device 1 configured as described above operates as follows.

During low/medium speed straight-ahead driving, the front and rear wheel side directional control valves 55F and 55R of the hydraulic circuit 4 shown in FIG. Both are set to the fully open state. Then, in the front wheel side hydraulic system 4a, the hydraulic pump 52
Hydraulic oil from F flows through pipe 54F and front wheel side direction control valve 55.
F. Since it returns to the reservoir 53F via the pipe line 60F, it is not supplied to the cylinder unit 1-16. On the other hand, the upper chamber 45F and the royal chamber 46F of the cylinder unit 16 are connected to the pipe line 5.
They communicate with each other via 6F, 58F, and 61F. Therefore, due to the torsional force transmitted from the front wheel side stabilizer bar 13, the piston 42F moves within the cylinder 41F by 1
The front wheel stabilizer bar 13 moves freely, and the front wheel stabilizer bar 13 exhibits almost no torsional rigidity. On the other hand, in the rear wheel side hydraulic system 4b, the hydraulic oil from the hydraulic pump 52R returns to the reservoir 53R via the pipe line 54R, the rear wheel side directional control valve 55R1 and the pipe line 60R, so that
is not supplied. On the other hand, the upper chamber 45R and lower chamber 46R of the cylinder unit 29 are connected to pipes 56R, 58R, and 61R.
communicate with each other via.

Therefore, due to the torsional force transmitted from the rear wheel side stabilizer bar 26, the piston 42R is moved to the cylinder 41R.
The stabilizer bar 26 on the rear wheel side also exhibits almost no torsional rigidity.

When traveling straight at high speed, the front wheel side and rear wheel side direction control valves 55F and 55R of the hydraulic circuit 4 shown in FIG. 7 are moved to the extended position 55F based on the detection results of the stroke sensors 33 and 34.
b, 55Rb or retracted positions 55Fc, 55Rc as appropriate, move the screws 1 to 42F, 42R to the neutral position and stroke O>, then move the front wheel side and rear wheel side directional control valves 55F, 55R to the neutral position. 55Fa, 55
At the same time, the front wheel side and rear wheel side linear solenoid valves 59F and 59R are set to the fully open state. As a result, the upper chamber 45F and the lower chamber 46 of the cylinder unit 16
F and the upper chamber 45R and lower chamber 46 of the cylinder unit 29
Both pistons 42F and 42R are fixed at neutral positions. Therefore, the cylinder unit 16 is located at one end 13a of the front wheel side stabilizer bar 13.
The connection distance between the front right wheel shock absorber 11 and the front right wheel shock absorber 11 is (l
! ! Also, the cylinder unit 2
9, the connection distance between one end 26a of the rear wheel stabilizer bar 26 and the right rear wheel shock absorber 24 is longer than the other end 26.
Since they are each fixed to be equal to the connection distance between b and the left rear wheel shock absorber 21, the front wheel side and rear wheel side stabilizer bars 13° and 26 each exert their own torsional rigidity to maintain the vehicle posture when traveling straight at high speed. stabilize.

On the other hand, during cornering, the front wheel side and rear wheel side direction control valves 55F, 55R are switched to the extended positions 55Fb, 55Rb or the retracted positions 55Fc, 55Rc, and the front wheel side and rear wheel side linear renoid valves 59F, 59R are driven at the duty ratio. to control the flow rate of hydraulic oil.

That is, when driving in a left turn, the hydraulic circuit 4 shown in FIG.
front wheel side and rear wheel side direction control valves 55F.

55R are both set at contracted positions 55Fc and 55Rc. Then, in the front wheel side hydraulic system 4a, hydraulic oil is supplied to the upper chamber 45F of the front wheel side cylinder unit 16 via the hydraulic pump 52F1 pipe 54F and the front wheel side directional control valve 55F1 pipe 56F, and the hydraulic oil is supplied to the upper chamber 45F of the front wheel side cylinder unit 16. The hydraulic oil in the royal chamber 46F of the cylinder unit 16 flows out to the reservoir 53F via the pipe 57F, the rear wheel side direction control valve 55F, and the pipe 60F.

Therefore, the cylinder units 1 to 16 contract. Eventually,
When the ECU 3 determines that the piston 42F of the front wheel cylinder unit 16 has contracted by the front wheel target stroke acid based on the detection result of the stroke sensor 33,
By controlling the flow rate of hydraulic oil by driving the front wheel side linear solenoid valve 59F with a duty ratio, the piston 42
F is fixed in a contracted state that matches the front wheel side target stroke amount.

In addition, in the rear wheel side hydraulic system 4b, hydraulic oil is supplied to a hydraulic pump 52R1 a pipe 54R1 a rear wheel side directional control valve 55R1 a pipe 5
Upper chamber 45 of the cylinder unit 29 on the rear wheel side via 6R
The hydraulic oil in the lower chamber 46R of the cylinder unit 29 on the rear wheel side is supplied to the rear wheel side cylinder unit 29 through the pipe 57R1 and the rear wheel side direction control valve 55
It flows out to the R1 arbor 53R via the R1 conduit 60R.

Eventually, as in the case described above, the rear wheel side linear lenoid valve 59R
The piston 42R is fixed in a contracted state (a state in which it is contracted by the target stroke acid on the rear wheel side).

In this way, as shown in FIG. 8, by contracting the front wheel side cylinder unit 16, the torsional rigidity of the front wheel side stabilizer bar 13 is actively increased, and the right front wheel 10 is moved downward, and the left front wheel 6 is moved downward. move upward. Also, the 9th
As shown in the figure, by contracting the rear wheel side cylinder unit 29, the torsional rigidity of the rear wheel side stabilizer bar 26 is actively increased, and the right rear wheel 23 is moved downward and the left rear wheel 20 is
move upward. Therefore, as shown in FIGS. 8 and 9, the roll angle β of the vehicle decreases. Roughly speaking, here, for example, when turning at low to medium speeds, if the target stroke amount of the rear wheels is made larger than the target stroke amount of the front wheels, the torsional rigidity of the front wheel stabilizer bar 13 is Since the torsional rigidity of the wheel-side stabilizer bar 26 becomes relatively high, the value of the stability factor Kh already mentioned in the [Effect] section becomes negative, and the turning characteristics of the vehicle become more toward oversteer characteristics than the basic turning characteristics. Transition. On the other hand, when turning at high speed, if the front wheel target stroke is made larger than the rear wheel target stroke amount, the torsional rigidity of the front wheel stabilizer bar 13 becomes relatively higher than the torsional rigidity of the rear wheel stabilizer bar 26. [The value of the stability factor Kh already mentioned in the section ``Effect'' becomes positive, and the turning characteristics of the vehicle shift from the basic turning characteristics to the side of understeer characteristics.

On the other hand, when the vehicle is turning right, both the front wheel side and rear wheel side direction control valves 55F and 55R of the hydraulic circuit 4 shown in FIG. 7 are set to extended positions 55Fb and 55Rb. Then, in the front wheel side hydraulic system 4a, hydraulic oil is supplied to the lower chamber 46F of the front wheel side cylinder unit 16 via the hydraulic pump 52F, the pipe 54F, the front wheel side directional control valve 55F, and the pipe 57F, and the hydraulic oil is supplied to the lower chamber 46F of the front wheel side cylinder unit 16. The hydraulic oil in the upper chamber 45F of the side cylinder unit 16 is supplied to the pipe 56F, the rear wheel side direction control valve 55F, and the pipe 60.
It flows out to the reservoir 53F via F. Therefore, the cylinder unit 16 expands. Eventually, based on the detection result of the stroke sensor 33, when the ECU 3 determines that the screw 1-42F of the front-wheel cylinder unit 16 has extended the front-wheel target stroke acid, the front-wheel linear solenoid valve 59F is switched to duty. By controlling the flow of hydraulic oil through specific drive, the piston 42F is fixed in an extended state matching the front wheel side 1] mark 1-low cross.

In addition, in the rear wheel side hydraulic system 4b, hydraulic oil is supplied to a hydraulic pump 52R1 a pipe 54R1 a rear wheel side directional control valve 55R1 a pipe 5
Lower chamber 46 of the cylinder unit 29 on the rear wheel side via 7R
The hydraulic oil in the upper chamber 45R of the cylinder unit 29 on the rear wheel side is supplied to the rear wheel side directional control valve 55 in the pipe 56R1.
It flows out to the reservoir 53R via the R1 pipe 60R. Eventually, similarly to the case described above, the piston 42R is fixed in an extended state (a state in which it is extended by the target rear wheel stroke amount) by the rear wheel side linear solenoid valve 59R.

In this way, as shown in FIG. 10, by extending the front wheel side cylinder unit 16, the torsional rigidity of the front wheel side stabilizer bar 13 is actively increased, and the right front wheel 10 is moved upward, and the left front wheel is Move 6 downward. Also, the first
As shown in FIG. 1, by extending the rear wheel side cylinder unit 29, the torsional rigidity of the rear wheel side stabilizer bar 26 is actively increased, and the right rear wheel 23 is moved upward and the left rear wheel 20 is
move downward. Therefore, as shown in FIGS. 10 and 11, the roll angle β of the vehicle decreases.

Furthermore, here, for example, when turning at low to medium speeds,
When the rear wheel side stroke is larger than the front wheel side stroke, the front wheel side stabilizer light t-aver-13
Since the torsional rigidity of the rear wheel stabilizer bar 26 is relatively high with respect to the torsional rigidity of The characteristic shifts to the oversteer characteristic side.

On the other hand, when turning at high speed, if the front wheel target stroke amount is made larger than the rear wheel target stroke amount, the torsional rigidity of the front wheel stabilizer bar 13 becomes relatively higher than that of the rear wheel stabilizer bar 26. [Effect]
The value of the stability factor Kh already mentioned in the above section becomes positive, and the turning characteristics of the vehicle shift from the basic turning characteristics to the understeer characteristics side.

The operation of the vehicle attitude control device 1 as described above is carried out by the ECU 3
This is realized by executing the vehicle attitude control process as shown in the flowchart of FIG. This vehicle attitude control process is started upon activation of the ECU 3.

First, in step 100, initialization processing such as clearing the RAM 5 and C of the ECtJ5, resetting various flags and counters, and setting initial values is performed. Next step 110
Then, a process of reading the vehicle speed V detected by the vehicle speed sensor 31 is performed. Next, the process proceeds to step 120, where a process of reading the steering angle θ detected by the steering sensor 32 is performed. In the subsequent mesotub 130, it is determined whether or not the vehicle is traveling straight ahead, and if the determination is affirmative, the process proceeds to step 260, while if the determination is negative, the process proceeds to step 14.
Each goes to 0. The determination in step 130 is made based on whether the steering angle θ read in step 120 is within the normal play of the steering wheel 18 (3° to 5°).

That is, if the steering angle θ is smaller than the play of the steering wheel 18, it is determined that the vehicle is traveling straight ahead. In step 140, which is executed when it is determined in step 130 that the vehicle is not traveling straight, the acceleration G in the vehicle width direction is calculated from the vehicle speed V read in step 110 and the steering angle θ read in step 120 as follows: The process of exiting as shown in (5) is performed.

G=f(θ)/■2...(5)
However, f is a function that defines the relationship between the steering angle θ and the turning radius R when turning at the vehicle speed ■. In addition, the square value of the turning angular velocity of the vehicle when the vehicle is turning and the turning radius R
The vehicle width direction acceleration G may be obtained from the product of .

Next, the process proceeds to step 150, in which a front wheel side target stroke ff1sFo is calculated based on the vehicle speed ■ read in step 110 and the vehicle width direction acceleration G calculated in step 140, according to the map shown in FIG. Processing is performed. In the following step 160, similarly, based on the vehicle speed and the acceleration G in the vehicle width direction, a process is performed to calculate the rear wheel side target stroke amount to low stroke according to the map shown in FIG. That is, as shown in the map of FIG. 13, vehicle speed V, vehicle width direction acceleration G, heavy wheel side target stroke amount (value on the plane including the broken line in the figure), and rear wheel side target stroke amount ( In the same figure, the relationship with the value on the surface including the line shown by the dashed-dotted line is defined. In addition, FIG. 13 shows the map of this example when the vehicle speed V is 0 to 90 [Km/h]
, is a partial view broken in the range of vehicle width direction acceleration G from O to 0.6 [C1], and the front wheel side and rear wheel side target stroke amounts are expressed as a ratio (in mm) to each maximum value (
The maximum value is 100 [%]. ) is displayed. When at least one of the values of vehicle speed V and vehicle width direction acceleration G shifts in the direction shown by arrow X in the same figure on a plane including the vehicle speed axis and vehicle width direction acceleration axis, the front wheel side target stroke amount decreases; As the rear wheel side target stroke increases, the turning characteristics of the vehicle shift from the basic turning characteristics to the oversteer characteristics side, and the oversteer characteristics gradually become stronger. In this case, the restoring force for the mouth to ring of the vehicle is generated by the rear wheel stirrer bar 26, which has relatively high torsional rigidity. Conversely, when at least one of the values of vehicle speed and vehicle width direction acceleration G shifts in the direction shown by arrow Y in the figure on a plane including the vehicle speed axis and vehicle width direction acceleration axis, the front wheel side target stroke amount increases; , the distance between the rear wheel side target speed I and loaf decreases, so the turning characteristics of the vehicle shift from the basic turning characteristics to the understeer characteristics side, and the understeer characteristics gradually become stronger. In this case, the restoring force against rolling of the vehicle is generated by the front wheel stabilizer bar 13, which has relatively high torsional rigidity. The ECU 3 stores a map as shown in FIG. 13 in advance in the ROM 5b, and based on the values of the vehicle speed V and the vehicle width direction acceleration G, according to the above map,
Calculate the front wheel side and rear wheel side target stroke amounts.

Next, the process proceeds to step 170, where it is determined whether or not the turning direction of the vehicle is to the right based on the steering angle θ read in step 120, and if an affirmative determination is made, the process proceeds to step 180.
On the other hand, if the determination is negative, the process proceeds to step 240. In step 180, which is executed when the vehicle is turning right, the front wheel direction control valve 55F (the control signal when turning right, that is, the front wheel direction control valve 55F is moved to the extended position 55Fb).
Processing is performed to output a control signal for switching to.

In the subsequent step 190, a process is performed to output a control signal for right-turning to the rear wheel direction control valve 55R, that is, a control signal for switching the rear wheel direction control valve 55R to the extended position 55Rb. Next, the process proceeds to step 200, where the piston 4 is moved by the calculated front wheel side target stroke l5FO.
Front wheel side linear solenoid valve 59 so that 2F moves.
A process of outputting a duty ratio control signal to F is performed.

In the subsequent step 210, a process is performed to output a duty ratio control signal to the rear wheel side linear renoid valve 59R so that the piston 42R moves by the calculated rear wheel side target stroke 15RO.

Next, proceeding to step 220, the stroke sensor 33.3
4 detected front wheel side and rear wheel side pistons 42F, 4
A process of reading the actual stroke suspension SF and SR of 2R is performed. In the following step 230, the above step 220
The front wheel actual stroke ISF read in is equal to the calculated front wheel target stroke amount SFOM, and the rear wheel actual stroke ff1sR read in step 220 above.
It is determined whether or not the rear wheel side target stroke ff1sRo is equal to the squeezed out target stroke ff1sRo.
, 42R is both target strokes SFO, SRO piston 42F, 42R is each target stroke jtisFo,
Assuming that only SRO has not moved yet, the process returns to step 200, and the duty ratio control of the front linear solenoid valve 59F or the rear linear solenoid valve 59R is continued.

On the other hand, in step 240, which is executed when it is determined in step 170 that the car is turning left, the front wheel side direction control valve 55F receives a control signal for turning left.
A process is performed to output a control signal for switching the front wheel side direction control valve 55F to the retracted position 55Fc. In the subsequent step 250, a process is performed to output a control signal for left-turning travel to the rear wheel direction control valve 55R, that is, a control signal for switching the rear wheel direction control valve 55R to the retracted position 55Rc. Thereafter, the process moves to step 200 described above.

On the other hand, in step 260, which is executed when it is determined in the above step 130 that the vehicle is traveling straight, it is determined whether the Φ speed V read in the above step 110 is equal to or higher than the reference vehicle speed VO, and an affirmative determination is made. If it is determined, step 30
On the other hand, if the determination is negative, the process proceeds to step 270. If it is determined that the vehicle speed V is less than the reference vehicle speed O,
In other words, step 2 is executed while driving straight at low/medium speeds.
70, the cylinder unit 1d on the front wheel side and the rear wheel side
, 29 is set to be movable. In the following step 280, both the front wheel side and rear wheel side direction control valves 55F and 55R are set to the neutral position 5.
A process is performed to output a control signal for switching between 5Fa and 55Ra.

Next, the process proceeds to step 290, where a signal is output to set the front and rear wheel linear solenoid valves 59F and 59R to the all-U old state, and the front and rear cylinder units 16.
After making the pistons 42F and 42R of No. 29 movable, the process returns to step 110.

On the other hand, if it is determined in step 260 that the vehicle speed V is equal to or higher than the reference vehicle speed vO, that is, in step 300, which is executed during high-speed straight running, the stroke d of the front wheel side and rear wheel side cylinder units 16.29 is That is, a process is performed to set the screws I to 42F and 42R to the neutral position. In the following step 310, the pistons 42F of the front wheel side and rear wheel side cylinder units 16.29,
Based on the detection results of the stroke sensors 33 and 34, the front wheel side and rear wheel side direction control valves 55F and 55R are moved to the neutral position 55Fa, 55R so as to move the front and rear wheel side direction control valves 55F and 55R to the neutral position, respectively.
55Ra, extended position 55Fb, 55Rb, contracted position 55
Fc, 55Rc, and at the same time, the front wheel side and rear wheel side gravity near solenoid valves 59F, 59R are controlled to temporarily increase the duty ratio, and the piston 42F
, 42R reach the neutral position, and when they each reach the neutral position, a process is performed to output a control signal to set the front wheel side and rear wheel side directional control valves 55F, 55R to the neutral positions 55Fa, 55Ra. . Next, the process proceeds to step 320, where a signal is output to fully open both the front and rear linear renoid valves 59F and 59R, and the pistons 42F and 42R of the front and rear cylinder units 16.29 are placed in the neutral position. After holding, the process returns to step 110 above. Thereafter, the vehicle attitude control process repeats steps 110 to 320 described above.

Note that in this embodiment, the cylinder unit 16 on the front wheel side
and the hydraulic circuit 4 are connected to the front wheel side adjustment means M1, and the rear wheel side cylinder unit 29 and the hydraulic circuit 4 are connected to the rear wheel side adjustment means M2.
The vehicle speed sensor 31 and the steering sensor 32 each correspond to the turning state signal generating means M3. Also, ECU3
Among the processes executed by (steps 150, 160, 1
70,180.190,200,210,240,25
0> as the control means M4, (steps 150, 160
) each function as a changing means M5.

As explained above, in this embodiment, the vehicle speed V and the steering angle θ
The front wheel side target stroke amount and the rear wheel side target stroke amount are determined according to the map based on the vehicle width direction acceleration G and the vehicle speed V obtained from In order to achieve the target stroke, on the other hand, the actual stroke of the piston 42R of the cylinder unit 29 on the rear wheel side is controlled to be the target stroke amount on the rear wheel side.

For this reason, during cornering, the front wheel side and rear wheel side stabilizer bars 13.
By actively increasing the torsional rigidity of the stabilizer bar 26 and, moreover, increasing the torsional rigidity of the stabilizer bar 26 on the rear wheel side more than the torsional rigidity of the stabilizer bar 13 on the front wheel side during low to medium speed turning, the turning characteristics of the vehicle can be improved. By changing the predetermined basic turning characteristics to oversteer characteristics, and on the other hand, increasing the torsional rigidity of the stabilizer bar 13 on the front wheel side and the torsional rigidity of the stabilizer bar 26 on the rear wheel side during high-speed turning, the vehicle Since the turning characteristics of the vehicle are changed to the angle steering characteristics side rather than the basic turning characteristics, it is possible to suitably achieve both suppression of rolling of the vehicle during turning and control to change the turning characteristics of the vehicle to match the turning characteristics.

In addition, as a result of the above effects, the turning limit performance of the vehicle is increased and rolling during turning can be suppressed, making it possible to improve both the maneuverability and stability of the vehicle and the ride comfort when turning. .

Roughly speaking, the turning characteristics of the vehicle are changed from the basic turning characteristics to oversteer characteristics when turning at low to medium speeds, and to angesteer characteristics rather than the basic turning characteristics when driving at high speeds, so the driver can change the turning characteristics depending on the vehicle speed. By always operating the steering wheel 18 with the same steering sensation, the vehicle can be operated according to one's intention. In this way, the burden on the driver is reduced, and the driving operation of the vehicle becomes easier.

In addition, there is no need to newly install a dedicated device for changing vehicle turning characteristics on the vehicle, and the front wheel side stabilizer bar 13.26, which has been conventionally used to suppress rolling when the vehicle is turning, and the front wheel side stabilizer bar 13. Since the vehicle turning characteristics can be changed using the side and rear cylinder units 16, 29, hydraulic circuit 4, and ECU 3, there is no need to expand the mounting space or increase both Φ IM due to the installation of dedicated equipment, resulting in improved fuel consumption efficiency. No adverse effects such as deterioration or reduction in running performance or reliability of the device occur.

Furthermore, since there is no need to significantly change the mounting arrangement of vehicle-mounted equipment, it can be easily mounted on various vehicles, increasing the versatility of the device.

In addition, when driving straight at low or medium speeds, the pistons 42F and 42R of the cylinder units 16.29 on the front and rear wheels are
The torsional rigidity of the stabilizer bars 13.26 on the front and rear wheels is demonstrated by freely setting the t! Therefore, the road surface followability of the wheels and the ride comfort of the vehicle can be further improved.

Furthermore, when driving straight at high speed, the cylinder units 16.29 on the front and rear wheels are
is maintained at a neutral position (stroke amount O), so that straight-line stability when the vehicle is traveling straight at high speed is improved.

In this embodiment, each wheel 6, 10, 20°23 is connected to each shock absorber 7.11.21.24 and each [1].
A vehicle having a structure in which the arms 8, 12, 22, and 25 are directly attached to the small body 9 has been described. However, for example,
Even if the device of the present invention is applied to a vehicle having a structure in which each wheel is attached to the vehicle body through the chassis, the same effect on rolling suppression can be achieved because the rigidity of the vehicle body due to the chassis is high.

Further, in this embodiment, the target stroke amounts for the front wheels and the rear wheels are determined according to the map, but they may be determined based on an arithmetic expression from the vehicle speed V and the acceleration G in the narrow direction. For example, the same effect as in this embodiment can be obtained even if the vehicle speed, the detected value of the vehicle width direction acceleration sensor, the vehicle speed, the detected value of the yaw rate sensor, etc. are determined according to an arithmetic expression or map.

Roughly speaking, in this embodiment, the torsional rigidity of the stabilizer bars 13.26 on the front and rear wheels is determined by the pistons 42F and 42R of the cylinder units 16.29 on the front and rear wheels.
For example, it is possible to change the torsional rigidity of the stabilizer bar, which is divided into two parts on the front and rear wheels, by a hydraulic actuator installed in the divided parts. When the present invention is applied to a vehicle equipped with other scale actuators capable of changing the roll stiffness distribution of the vehicle, the effect of being able to change the turning characteristics of the vehicle at least during cornering can be sufficiently obtained. It will be done.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and it goes without saying that it can be implemented in various forms without departing from the gist of the present invention. be.

Effects of the Invention The vehicle attitude control device of the present invention roughly adjusts the target torsional suspension of the front and rear wheel stabilizers corresponding to the acceleration in the vehicle width direction of the vehicle determined based on the turning state of the vehicle. It is configured to change the front wheel side and the rear wheel side differently depending on the situation. Therefore, the relative magnitude between the torsional rigidity of the front wheel stabilizer amount A and the torsional rigidity of the rear wheel stabilizer can be changed according to the turning state of the vehicle, so that rolling of the vehicle during turning can be suppressed, and This provides an excellent effect in that the turning characteristics of the vehicle can be adjusted to the optimum turning characteristics for the turning condition during the turning operation.

In addition, as a result of the above effects, the turning limit performance of the vehicle is increased, and the vehicle attitude when turning can be controlled with high precision, so the maneuverability and stability of the vehicle are improved when turning.
Furthermore, the ride comfort will be even better.

Furthermore, in order to optimally adjust the turning characteristics of the vehicle according to the vehicle turning state, even if the steering wheel is operated with the same steering feeling all the time, the vehicle will behave according to the driver's intention, so the driving control This improves performance and reduces the burden on the driver when operating the vehicle.

In addition, without installing a dedicated device, etc., it uses a means to adjust the torsion of the front and rear wheel stabilizers, which have been conventionally provided to suppress rolling of the vehicle. It is possible to change the turning characteristics of the vehicle without causing adverse effects such as an increase in speed.

For example, the turning state signal generating means generates a speed signal according to the running state of the vehicle, and the changing means changes the target of the rear wheel stabilizer as the speed signal generated by the turning state signal generating means decreases. If the twist amount is changed to be larger than the maximum target twist of the front wheel stabilizer, the vehicle's 1-hour turning characteristic or basic turning characteristic will shift to the oversteer characteristic side, so the This improves responsiveness to steering operations, making it possible to make quick turns that suit the driver's wishes.

Further, for example, the turning state signal generating means generates a speed signal according to the running state of the vehicle, and the changing means controls the front wheel side stabilizer (adjustment) as the speed signal generated by the turning state signal generating means increases. If the target twist amount of the rear wheel stabilizer is changed to be larger than the target twist amount of the rear wheel stabilizer, the turning characteristics of the vehicle will shift from the basic turning characteristics to the understeer characteristics, so it will be difficult to resist disturbances during high-speed turning. Stability is improved and smooth cornering is possible.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram conceptually illustrating the content of the present invention, Fig. 2 (1) is an explanatory diagram showing the relationship between the turning radius during normal driving and the turning radius during extremely low speed, Fig. 2 (2) is a graph showing the relationship between the turning radius during normal driving divided by the turning radius during extremely low speed and the square value of the vehicle speed, Figure 3 (1) is a schematic diagram of vehicle turning 11+f, Figure 3 (2> is a graph showing the relationship between wheel load and cornering power, Figure 4 is a system configuration diagram of an embodiment of the present invention, Figure 5 is a longitudinal cross-sectional view of the same Schilling unit, and Figure 6 is a graph showing the relationship between wheel load and cornering power. A front view of the embodiment, FIG. 7 is an explanatory diagram showing the configuration of the hydraulic circuit and electronic control device, FIGS. 8 and 9. FIGS. 10 and 11 are explanatory diagrams showing the operation thereof, FIG. 12 similarly shows flowcharts 1 to 1 showing the control.
Figure 3 is a graph showing the same map. Ml...Front wheel side adjusting means M2...Rear wheel side adjusting means M3...Turning state signal generating means M4...Controlling means M5...Changing means 1...Vehicle attitude control device 4...・Hydraulic circuit 5...Electronic control unit (ECU) 5a...CPU 16.29...Cylinder unit] ~ 31...Vehicle speed sensor 32...Steering sensor

Claims (1)

[Scope of Claims] 1. Front wheel adjustment means for adjusting the amount of twist of a front wheel stabilizer that connects unsprung members of left and right front wheels of a vehicle in accordance with an external command; Rear wheel adjustment means for adjusting the amount of twist of the rear wheel stabilizer that connects the unsprung member in accordance with an external command; and Turning state signal generating means for generating a turning state signal according to the turning state of the vehicle. and a command to set the torsion amount of the front wheel stabilizer and the rear wheel stabilizer to a target torsion amount corresponding to the vehicle widthwise acceleration of the vehicle determined based on the turning state signal generated by the turning state signal generating means. In a vehicle attitude control device, the vehicle attitude control device includes: a control means applied to the front wheel side adjustment means and the rear wheel side adjustment means; further, the control means 1. A vehicle attitude control device comprising a changing means for changing the target twist amount of the front wheel stabilizer and the target twist amount of the rear wheel stabilizer so that they are different from each other. 2. The turning state signal generating means generates a speed signal corresponding to the traveling speed of the vehicle, and the changing means changes the speed signal of the rear wheels according to a decrease in the speed signal generated by the turning state signal generating means. The vehicle attitude control device according to claim 1, wherein the target twist amount of the side stabilizer is changed to be larger than the target twist amount of the front wheel side stabilizer. 3. The turning state signal generating means generates a speed signal corresponding to the traveling speed of the vehicle, and the changing means changes the speed signal on the front wheel side as the speed signal generated by the turning state signal generating means increases. The vehicle attitude control device according to claim 1, wherein the target twist amount of the stabilizer is changed to be larger than the target twist amount of the rear wheel side stabilizer.