JP2020131739A - Vehicle posture control device - Google Patents

Abstract

To provide a vehicle posture control device that enables operability of steering by a driver to be improved and can control pitch motion with good responsiveness.SOLUTION: A posture control device 4 comprises: reference longitudinal acceleration calculation means 23; reference yaw-rate calculation means 14; target pitch motion setting means 15; and command value correction means 16 that corrects a braking/driving force command value and a rear-wheel steering angle command value so that vehicle body motion approximately matches reference longitudinal acceleration, reference yaw-rate and target pitch motion. Moment distribution means 16a in the command value correction means distributes sum ΔMof pitch moments generated by the correction into pitch moments ΔMgenerated by correcting the braking/driving force command value and pitch moments ΔMgenerated by correcting the rear wheel steering angle command value. The moment distribution means 16a sets magnitude of the moments to be divided, on the basis of a derivative value and the like of the pitch moments ΔM.SELECTED DRAWING: Figure 8

Description

The present invention relates to a vehicle attitude control device that improves the driving operability of a driver by controlling the pitch motion according to the steering of the driver or the like.

Suspension control device that calculates the target pitch angle, which is a downward pitch motion according to the lateral acceleration calculated from the vehicle speed and steering angle, and adjusts the damping force of the shock absorber or the pressure of the air suspension so that the target pitch angle is obtained. Is shown (Patent Document 1).
In addition, in order to suppress the lifting of the vehicle body during turning, a vehicle body behavior control device that controls the left and right toe angles of the front wheels and adjusts the toe angle so that the force input in the lateral direction of the vehicle body is equal on the left and right is shown. (Patent Document 2).

Japanese Unexamined Patent Publication No. 2011-31795 Japanese Unexamined Patent Publication No. 2008-168743

Toshio Tanaka, Yudai Suzuki, Shuichi Kosaka, Wei Peng, Makoto Yamamon, Yoshiro Kano, Masato Abe, "Effects of Body Motion on G-Vectoring Control", Society of Automotive Engineers of Japan, 2017 Spring Meeting Academic Lecture Proceedings CD, 2015163, PP888-892

In Patent Document 1, when adjusting the damping force of the shock absorber, it is difficult to lift the vehicle body because the pitch motion or the roll motion generated in the vehicle body is passively controlled, and the controllable motion is limited. Further, when an air suspension is used, active movement is possible, but the response is low, so that there is a risk of a response delay.

In Patent Document 2, in the front wheel, a jack-down force is generated on the front wheel side of the vehicle body by increasing the steering angle of the toe angle of the inner ring with respect to the toe angle of the outer ring at the initial stage of turning or by advancing the phase. I have a good roll feeling. However, it is necessary to combine the front wheels with toe angle adjusting means for expanding and contracting the lengths of the left and right tie rods in addition to the normal steering device, and due to the complicated configuration, there is a risk that cost and vehicleability will be a problem. Further, since the lateral force of the tire is generated by the deformation of the ground contact portion of the tire, the responsiveness is low and the response may be delayed.

An object of the present invention is to provide a vehicle attitude control device capable of improving the driving operability of steering by a driver and controlling pitch motion with good responsiveness.

The vehicle attitude control device 4 of the present invention includes a vehicle speed detecting means 5 that detects the speed of the vehicle, a steering angle detecting means 6 that detects the steering angle of the front wheels 7, and an accelerator that detects the accelerator operating amount of the accelerator operating means of the vehicle. Operation amount detection means 11, brake operation amount detection means 12 for detecting the brake operation amount of the vehicle brake operation means, control drive capable of adjusting the braking force or driving force of the left and right front and rear wheels 7 and 8. A posture control device for controlling the posture of a vehicle including a force control device 13 and a rear wheel steering angle control device 2 capable of adjusting the steering angles of the rear wheels 8.
In the vehicle, a pitch moment is generated in the vehicle body by a vertical force acting on the vehicle body via the suspensions 9 and 10 of the front and rear wheels 7.8 by the control driving force adjusted by the control driving force control device 13. The rear wheel steering angle control device 2 adjusts the steering angle of the rear wheels 8, and the lateral force generated in the rear wheels 8 acts on the vehicle body via the suspension 10 of the rear wheels 8. It is a vehicle in which a pitch moment is generated in the vehicle body.
Based on the accelerator operation amount and the brake operation amount, the control driving force command value of each of the wheels 7 and 8 is calculated, and the reference front-rear acceleration calculation means 23 for calculating the reference front-rear acceleration of the vehicle from the control drive force command value. When,
The reference yaw rate calculation means 14 for calculating the reference yaw rate of the vehicle based on the vehicle speed detected by the vehicle speed detection means 5, the steering angle, and the rear wheel steering angle command value given according to the determined conditions.
A target pitch motion setting means 15 for setting a target pitch angle or a target pitch angular velocity to be a target pitch motion based on the vehicle speed, the steering angle, and the rear wheel steering angle command value.
The command value correction means 16 for correcting the control driving force command value and the rear wheel steering angle command value so that the vehicle body motion substantially coincides with the reference front-rear acceleration, the reference yaw rate, and the target pitch motion. ,
The command value correction means 16 combines the sum of the pitch moments generated by the correction of the control driving force command value and the rear wheel steering angle command value with the pitch moment generated by the correction of the control drive force command value and the said. It has a moment distribution means 16a that distributes to the pitch moment generated by the correction of the rear wheel steering angle command value.
The moment distribution means 16a is a value representing a time change characteristic of the pitch moment generated by correcting the control driving force command value and the rear wheel steering angle command value, or a time change characteristic of the rear wheel steering angle command value. The magnitude of the distributed moment is set based on the value representing.
The above-mentioned determined conditions are conditions arbitrarily determined by design or the like, and are determined by, for example, obtaining appropriate conditions by either one or both of a test and a simulation.

According to this configuration, the command value correction means 16 corrects the control driving force command value and the rear wheel steering angle command value so that the vehicle body motion substantially coincides with the reference front-rear acceleration, the reference yaw rate, and the target pitch motion. In other words, by calculating the target pitch angle or target pitch angular velocity that is the target pitch motion according to the steering angle and vehicle speed, and correcting the control driving force command value and the rear wheel steering angle command value of the front and rear wheels 7 and 8. A pitch moment is freely generated in the vehicle body, and the pitch motion is controlled so as to substantially match one of the target values. Diagonal, that is, a diagonal change in posture, which is a combination of this pitch movement and the roll movement generated by turning, realizes steering with a margin for the driver, thereby improving the driving operability of the driver's steering. it can.

In this case, the moment distribution means 16a in the command value correction means 16 sets the sum total ΔM _p of the pitch moments generated by the correction, the pitch moment ΔM _px generated by the correction of the control driving force command value, and the rear wheel steering angle command value. It is distributed to the pitch moment ΔM _py generated by the correction of. This moment distribution means 16a is for setting the magnitude of the moment based on the value representing the time variation characteristics of the pitch moment ΔM value representing a time variation characteristic of the _p or the rear wheel steering angle command value [delta] _r,, distributes, A component that changes quickly can be generated by the driving force, and a component that changes slowly can be generated by the steering angle of the rear wheels. When the time change characteristic of the pitch moment ΔM _p or the rear wheel rudder angle command value δ _r is large, the pitch moment is responsive mainly by controlling the pitch moment by the controlling driving force that can be generated with good responsiveness. This is to generate it with good sex. When a lateral force is generated by a tire, the lateral force is generated by steering the wheel portion and deforming the ground contact portion of the tire so as to be twisted, so that the responsiveness is not good. In the case of the controlled driving force, the rigidity of the tire in the front-rear direction is high, so that the responsiveness is high, and the pitch moment can be generated with good responsiveness. Therefore, the responsiveness in pitch motion control can be improved.

The moment distributor means 16a, the braking-driving force command value and the differential value of the pitch moment .DELTA.M _p generated by correcting the rear wheel steering angle command value, or the differential value of the rear wheel steering angle command value [delta] _r Based on this, the magnitude of the distributed moment may be set.
The moment distributor means 16a, the magnitude of the differential value of the pitch moment .DELTA.M _p, or when the magnitude of the differential value of the rear wheel steering angle command value [delta] _r exceeds the threshold value, the rear wheel steering angle command value The distribution ratio to the pitch moment ΔM _py generated by the correction may be reduced.
The threshold value is a threshold value arbitrarily determined by design or the like, and is determined by obtaining an appropriate threshold value by, for example, one or both of a test and a simulation.
According to this configuration, the control system can be simplified and the calculation load can be reduced by reducing the distribution ratio to the pitch moment ΔM _py with the threshold value as a boundary.

When the magnitude of the differential value of the pitch moment ΔM _p or the magnitude of the differential value of the rear wheel steering angle command value δ _r becomes equal to or greater than the threshold value, the moment distribution means 16a has the rear wheel steering angle command value. The distribution ratio to the pitch moment ΔM _py generated by the correction of may be set to zero.
The threshold value is a threshold value arbitrarily determined by design or the like, and is determined by obtaining an appropriate threshold value by, for example, one or both of a test and a simulation.
In this case, the corrected rear wheel steering angle command value can be prevented from exceeding the controllable maximum value of the rear wheel steering angle.

The moment distributor means 16a, based on the frequency characteristics of the pitch moment .DELTA.M _p, may be set the magnitude of the moment the distribution.
The moment distributor means 16a distributes a low-frequency component of the pitch moment .DELTA.M _p as pitch moment .DELTA.M _py generated by the correction of the rear wheel steering angle command value, the braking-driving the pitch moment except for the low-frequency component It may be distributed as the pitch moment ΔM _px generated by the correction of the force command value. In this case, the moment distributor means 16a, may be partitioned between high and low frequency components of the pitch moment .DELTA.M _p example a low-pass filter 16aa.

The command value correction means 16 may perform the correction so as to cause the vehicle to make a pitch motion in the front-down direction by at least lifting the rear wheel side of the vehicle body. In this case, since the pitch movement occurs with the front wheel side of the vehicle body as the fulcrum, a force that is pressed against the seat is generated on the driver's body and comes into close contact with the seat, so that the driver can feel secure. In addition, the pitch motion can be efficiently controlled to improve the driving operability of the driver's steering.

When the magnitudes of the controlling driving force of the front wheels 7 and the rear wheels 8 are equal, the vehicle has the front wheels with respect to the vertical force acting on the vehicle body via the suspensions 9 and 10 of the front and rear wheels 7 and 8. When the rear wheel 8 is larger than 7 and the steering angles of the front wheel 7 and the rear wheel 8 are equal, the lateral force generated by the tire acts on the vehicle body via the suspensions 9 and 10. The vehicle may have suspensions 9 and 10 in which the rear wheels 8 are larger than the front wheels 7 in terms of directional force. In this case, it becomes easy to control the vertical movement on the rear wheel side of the vehicle body. Therefore, the pitch motion can be controlled more efficiently.

In the vehicle, the height of the roll center position of the front wheel 7 may be substantially equal to the ground position.
When the jack-up angle of the front wheel 7 is equal to or less than the set angle (for example, several degrees or less), the height of the roll center position of the front wheel 7 is considered to be substantially equal to the ground position. The number of degrees is set based on, for example, the result of a simulation or an actual vehicle test.
The smaller the jack-up angle of the front wheels 7, the smaller the jack-up force of the front wheels 7 generated during turning, so that the disturbance when controlling the pitch motion becomes smaller.
According to this configuration, since the height of the roll center position of the front wheels 7 is substantially equal to the ground position, the jack-up angle of the front wheels 7 can be brought close to zero, and thus the disturbance when controlling the pitch motion can be reduced. Can be done. Therefore, it is possible to improve the posture stability of the vehicle when turning.

The vehicle may have a suspension in which the anti-dive angle of the front wheels 7 is substantially zero so that the vertical force generated through the suspension by the controlling driving force of the front wheels 7 becomes substantially zero.
The anti-dive angle of the front wheel 7 is substantially zero, which is synonymous with the case where the jack-up angle of the front wheel 7 is equal to or less than a set angle (for example, several degrees or less). The number of degrees is set based on, for example, the result of a simulation or an actual vehicle experiment.
According to this configuration, the force in the vertical direction generated through the suspension of the front wheels can be made substantially zero, which facilitates control of only the vertical movement on the rear wheel side of the vehicle body.

The vehicle control device of the present invention includes a vehicle speed detecting means for detecting the speed of the vehicle, a steering angle detecting means for detecting the steering angle of the front wheels, and an accelerator operating amount detecting means for detecting the accelerator operating amount of the accelerator operating means for the vehicle. A brake operation amount detecting means for detecting the brake operation amount of the vehicle brake operation means, a control driving force control device capable of adjusting the braking force or driving force of the left and right front and rear wheels, and a steering angle of the rear wheels. It is an attitude control device for controlling the attitude of a vehicle provided with a rear wheel steering angle control device capable of adjusting the steering angle, and the vehicle uses the control driving force adjusted by the control drive force control device to control the suspension of the front and rear wheels. A pitch moment is generated in the vehicle body by a vertical force acting on the vehicle body through the vehicle body, the steering angle of the rear wheels is adjusted by the rear wheel steering angle control device, and the lateral force generated in the rear wheels causes the rear wheels to operate. A vehicle in which a pitch moment is generated in the vehicle body by a vertical force acting on the vehicle body via the suspension, and a control driving force command value of each wheel is calculated based on the accelerator operation amount and the brake operation amount. , The reference front-rear acceleration calculation means for calculating the reference front-rear acceleration of the vehicle from the control driving force command value, the vehicle speed detected by the vehicle speed detection means, the steering angle, and the rear wheel rudder given according to the determined conditions. A reference yaw rate calculation means for calculating the reference yaw rate of the vehicle based on the angle command value, and a target pitch angle or target to be a target pitch motion based on the vehicle speed, the steering angle, and the rear wheel steering angle command value. The control driving force command value and the rear wheel steering angle command value so that the target pitch motion setting means for setting the pitch angle velocity and the vehicle body motion substantially match the reference front-rear acceleration, the reference yaw rate, and the target pitch motion. The command value correction means comprises a command value correction means for correcting the above, and the command value correction means sets the sum of the pitch moments generated by the correction of the control driving force command value and the rear wheel steering angle command value as the control driving force command value. It has a moment distribution means that distributes the pitch moment generated by the correction of the above and the pitch moment generated by the correction of the rear wheel steering angle command value, and the moment distribution means includes the control driving force command value and the said control driving force command value. The magnitude of the moment to be distributed is determined based on a value representing the time change characteristic of the pitch moment generated by correcting the rear wheel steering angle command value or a value representing the time change characteristic of the rear wheel steering angle command value. Set. Therefore, it is possible to improve the driving operability of the driver's steering and to control the pitch motion with good responsiveness.

It is a block diagram which shows the conceptual structure of the vehicle provided with the attitude control device which concerns on one Embodiment of this invention. It is sectional drawing of the in-wheel motor drive device of the vehicle. It is a figure explaining the motion on the XY plane of the vehicle. It is a figure explaining the pitch moment generated by the front-rear force acting on each wheel. It is a figure explaining the pitch moment generated by the lateral force acting on each wheel. It is a perspective view explaining the positional relationship of each roll center of a front-rear wheel. It is a block diagram of the control system of the vehicle. It is a block diagram which shows the detail of the attitude control device of the vehicle. The figure which shows the steering angle, the pitch angle, the pitch angular velocity, the pitch moment command value, the differential value of the pitch moment command value, the corrected driving force command value, and the corrected rear wheel steering angle command value at the time of control operation of the same attitude control device. Is. It is a figure which shows an example of the ratio set by the moment distribution means of the same attitude control device. It is a figure which shows another example of the ratio set by the same moment distribution means. It is a figure which shows still another example of the ratio set by the same moment distribution means. It is a figure which shows still another example of the ratio set by the same moment distribution means. FIG. 9 is a diagram showing an example of correcting a rear wheel steering angle command value when the rear wheel steering control method is applied in the example of FIG. 9. In the example of FIG. 9, it is a figure which shows the case where only the pitch motion which becomes the forward downward is applied.

<Outline configuration of vehicle>
The vehicle attitude control device according to the embodiment of the present invention will be described with reference to FIGS. 1 to 10.
FIG. 1 is a block diagram showing a conceptual configuration of a vehicle provided with an attitude control device according to an embodiment. This vehicle is an electric vehicle equipped with an in-wheel motor drive IWM on each of the four wheels.

<In-wheel motor drive device IWM>
As shown in FIG. 2, the in-wheel motor drive device IWM, which is a traveling drive device for a vehicle, includes a wheel bearing 20, an electric motor 21, and a speed reducer 22. The speed reducer 22 reduces and transmits the rotational output of the electric motor 21 to the hub wheel 20a, which is the rotating wheel of the wheel bearing 20. The wheels 7 and 8 (FIG. 1) are attached to the hub wheels 20a. The electric motor 21 is, for example, an AC motor such as a synchronous motor, and has a stator 21a and a rotor 21b.

<About control system>
As shown in FIG. 1, the vehicle has a front wheel steering angle control device 1, a rear wheel steering angle control device 2, an ECU 3, an attitude control device 4, a control driving force control device 13, a vehicle speed sensor 5 as a vehicle speed detecting means, and a steering angle. It includes a steering angle sensor 6 as a detecting means, an accelerator pedal sensor 11 as an accelerator operating amount detecting means, and a brake pedal sensor 12 as a brake operating amount detecting means.
The accelerator pedal sensor 11 is provided on an accelerator pedal or the like, which is an accelerator operating means of the vehicle, and detects an accelerator operating amount according to the accelerator depression amount of the driver and outputs the accelerator operating amount to the ECU 3. The brake pedal sensor 12 is provided on a brake pedal or the like, which is a vehicle brake operating means, and detects a brake operating amount according to the driver's brake depression amount and outputs the brake operating amount to the ECU 3.

The ECU 3 calculates the control driving force command value based on the input operation amount and outputs it to the attitude control device 4. The attitude control device 4 corrects the control driving force command value, which will be described later, and outputs the corrected control drive force command value to the control drive force control device 13. The control driving force control device 13 independently controls the control driving force of the four-wheel in-wheel motor drive device IWM based on the input corrected driving force command value.

The front wheel steering angle control device 1 is a device that controls the steering angle of the front wheels 7 according to the steering wheel operation of the driver. The front wheel steering angle control device 1 is based on, for example, the steering angle δ _h detected by the steering angle sensor 6, the vehicle speed V detected by the vehicle speed sensor 5, the steering torque of the driver detected by the steering torque sensor (not shown), and the like. , The torque or hydraulic pressure of an electric motor (not shown) is adjusted so as to assist the steering torque of the driver, and the steering angle of the front wheels 7 is controlled.

Further, the front wheel steering angle control device 1 outputs the steering angle to the ECU 3. The ECU 3 calculates the left and right rear wheel steering angle command values based on the vehicle speed and the steering angle, and outputs them to the attitude control device 4. The attitude control device 4 corrects the rear wheel steering angle command value, which will be described later, in the same manner as the control driving force command value, and outputs the corrected rear wheel steering angle command value to the rear wheel steering angle control device 2. The rear wheel steering angle control device 2 controls the steering angle of the rear wheels 8 independently on the left and right according to the corrected rear wheel steering angle command value output by the attitude control device 4.

<About movement on the XY plane>
As shown in FIG. 3, in the present embodiment, as a vehicle model traveling on an XY plane, a so-called two-wheeled vehicle model extended to four wheels will be described. Each wheel 7 and 8 of the vehicle while driving, cause longitudinal force X _i by the braking force is a driving force and regenerative braking by the electric motor 21 (FIG. 2) of the in-wheel motor drive device IWM (Figure 1), each lateral force Y _i corresponding to the traveling direction is an angle of the vehicle in a direction and the wheel position of the wheel 7 and 8 occurs. The subscript i indicates any one of fl: left front wheel, fr: right front wheel, rl: left rear wheel, and rr: right rear wheel.

各記号は以下のとおりである。
ｍ：車両重量、Ｖ：車速、β：横滑り角、ｒ：ヨーレート、ｄ_ｆ：前輪トレッド、ｄ_ｒ：後輪トレッド、ｌ_ｆ：前輪車軸から車両重心までの距離、ｌ_ｒ：後輪車軸から車両重心までの距離、Ｉ_ｚ：ｚ軸周りの慣性モーメント Movement on the X-Y plane resulting from the longitudinal force _{X i} and the lateral forces _{Y i} is as Equation (1) to (3).

Each symbol is as follows.
m: Vehicle weight, V: Vehicle speed, β: Side slip angle, r: Moment of inertia, d _f : Front wheel tread, _dr : Rear wheel tread, l _f : Distance from front wheel axle to vehicle center of gravity, l _r : From rear wheel axle Distance to the center of gravity of the vehicle, _Iz : Moment of inertia around the z-axis

<About pitch movement>
Next, consider pitch movement. If the roll motion is ignored, the pitch motion generated by the front-back force X _i and the lateral force Y _i is expressed by equations (4) to (6). PG in FIG. 4 is the position of the center of gravity.

<Pitch moment generated by front-back force>
M _px will be described with reference to FIG. M _px is a pitch moment generated by the front-back force X _i , and is represented by the equation (5). FIG. 4 illustrates how the control driving force of the in-wheel motor drive device IWM (FIG. 1) directly acts on the suspension mechanism in a vehicle having double wishbone suspensions 9 and 10 as an example.

Considering the front wheel 7, the intersection P4 _f of the extension lines of the upper arm 9a and the lower arm 9b in the front wheel suspension 9 is the instantaneous rotation center of the front wheel suspension 9. The angle formed by the instantaneous rotation center P4 _f and the wheel contact point P2 _f is the anti-dive angle θ _f .
Similarly, for the rear wheel 8, the anti-scuff angle θ _r, which is the angle formed by the instantaneous rotation center P4 _r of the rear wheel suspension 10 and the wheel contact point P2 _r , can be obtained.

For the sake of simplicity, assuming that the left and right front wheels 7 and 7 have the same anti-dive angle θ _f and the left and right rear wheels 8 and 8 have the same anti-scuff angle θ _r , the left and right front wheels 7 and 7 are front and rear. be given force _{X fl,} the _{X fr,} the vehicle body via a front wheel suspension _{9 - (X fl + X fr} ) · tanθ vertical force of _f acts. Similarly for the rear wheels 8, if the front-rear forces X _rl and X _rr are applied to the left and right rear wheels 8 and 8, the vertical force of (X _rl + X _rr ) · tan θ _r acts on the vehicle body via the rear wheel suspension 10. To do. Due to these vertical forces, a pitch moment M _px is generated around the vehicle center of gravity PG.

Since the anti-dive angle θ _f and the anti-scuff angle θ _r also exist in other suspension types, the pitch moment M _px is similarly generated by the front-rear force X _i . The pitch motion can be controlled by changing the front-rear forces X _fl , X _fr , X _rl , and X _rr of the front and rear wheels 7 and 8. However, varying the longitudinal force X _i, to change back and forth motion of the vehicle as shown in equation (1), taking into account the longitudinal movement, it is preferable to control the pitch motion of the vehicle. That is, before and after correction with by correcting the longitudinal force X _i of each wheel 7,8 so that the sum is substantially equal longitudinal force X _i, controls the pitch motion without giving the influence of the correction with respect to the longitudinal movement can do.

Further, by using the suspensions 9 and 10 having a small anti-dive angle θ _f and a large anti-scuff angle θ _r, it becomes easy to control the vertical movement on the rear wheel side of the vehicle body. Further, if the anti-dive angle θ _{f is set} to substantially zero, it becomes easy to control only the vertical movement on the rear wheel side of the vehicle body. In the correction of the rear wheel steering angle command value, which will be described later, the rear wheel steering angle is adjusted and the pitch motion is controlled by the vertical motion on the rear wheel side of the vehicle body. Therefore, by adopting such a vehicle configuration, the driving force and the rear wheel steering are controlled. Both the corners can control the vertical movement of the rear wheels of the vehicle.

<Pitch moment generated by lateral force>
_MPy will be described with reference to FIG. M _py is a pitch moment generated by the lateral force Y _i and is represented by the equation (6). Similar to FIG. 4, FIG. 5 illustrates a vehicle having a double wishbone suspension as an example. FIG. 5 is a view showing the rear wheel 8 from the rear of the vehicle. And the intersection point _{Pl rl} and _{Pl rr} of the respective extension lines of left and right upper arms 10a and lower arm 10b, the straight line intersection P3 _r passing through the ground contact point _{P2 rl} and _{P2 rr} of the rear wheels 8 is roll center of the rear wheel 8 .. The angle formed by the roll center P3 _r and the wheel contact points P2 _rl and P2 _rr is the jack-up angle γ _r .

Figure 5 is a schematic view of turning left, normal force lowering has a body acting on the vehicle body via a suspension 10 (the so-called jack-down force) is generated by the lateral force Y _rl of the left wheel 8, as well as the right wheel 8 A vertical force (so-called jack-up force) that lifts the vehicle body acting on the vehicle body via the suspension 10 is generated by the lateral force Y _rr . The resultant force of the vertical forces generated in the vehicle body by the lateral forces of the left and right wheels 8 and 8 in these rear wheels becomes the force for lifting or lowering the rear wheel side of the vehicle body. The same can be said for the front wheels. Since the jack-up angle γ _r also exists in other suspension types, the pitch moment M _py is similarly generated by the lateral force Y _i .

Here, the lateral force Y _i is represented by equations (7) to (10) using the front wheel steering angle and the rear wheel steering angle.

_{K i} of Equation (7) to (10) is a cornering power of the tire. The cornering power generally depends on the vertical load of the tire, and in a certain range, the cornering power increases qualitatively as the vertical load increases. Therefore, when the vehicle is turning left in FIG. 5, the vertical load of the right wheel 8 which is the turning outer ring becomes large. If the left and right wheel steering angles of the rear wheels are zero, the jack-up force (upward force) of the right wheel 8 is larger than the jack-down force (downward force) of the left wheel 8. A force to lift the car body is generated on the side. Here, if the steering angle of the right rear wheel 8 is δ _rr > 0, the lateral force Y _rr of the right rear wheel 8 becomes even larger, and the force to lift the vehicle body increases on the rear wheel side of the vehicle body. By controlling the angle, the pitch motion of the vehicle can be controlled.

However, when the lateral force Y _i is changed, the lateral motion and yaw motion of the vehicle also change as shown by the equations (2) and (3). Therefore, the lateral motion or the yaw motion of the vehicle is taken into consideration. It is preferable to control the pitch motion.
In both types, the lateral force of the rear wheels acts as the sum of the left and right wheels, so by adjusting the left and right rear wheel rudder angles (toe angles) so that the sum of the left and right wheels in the rear wheels does not change, pitch movement can be achieved. In addition, since yaw motion and lateral motion can be controlled, it is desirable that the rear wheel steering angle control device 2 (FIG. 1) can independently control the steering angles of the left and right wheels. In this case, the pitch motion can be controlled by the difference in the lateral force of the left and right rear wheels, and the lateral motion and the yaw motion of the vehicle can be controlled by the sum of the lateral forces of the left and right rear wheels.

<Regarding the positional relationship of each roll center of the front and rear wheels>
FIG. 6 shows the positional relationship between the roll center P3 _f of the front wheel 7 and the roll center P3 _r of the rear wheel 8. In this embodiment, since the pitch motion is effectively controlled by controlling the rear wheel steering angle, it is preferable that the roll center P3 _r of the rear wheels 8 is higher than the roll center P3 _f of the front wheels 7. The higher the roll center, the larger the jack-up angle, and the vertical force generated by the lateral force Y _i can be increased. That is, if the vehicle is designed so that the vertical force (jack-up force or jack-down force) acting on the vehicle body by the same lateral force is larger on the rear wheels 8 than on the front wheels 7, the steering angle of the rear wheels 8 is increased. The pitch motion can be efficiently controlled by controlling.

Further, the smaller the jack-up angle γ _f of the front wheels 7, the smaller the jack-up force of the front wheels 7 generated during turning, so that the disturbance when controlling the pitch motion becomes smaller. Therefore, the jack-up angle γ _f of the front wheel 7 is preferably close to zero degrees. In other words, the height of the roll center position of the front wheel 7 should be substantially equal to the ground position. When the jack-up angle γ _f of the front wheel 7 is equal to or less than the set angle (for example, several degrees or less), the height of the roll center position of the front wheel 7 is considered to be substantially equal to the ground position.

Further, in FIG. 6, the roll center position is located above the ground for both the front and rear wheels 7 and 8. This is because when the position of the center of gravity of the vehicle is closer to the roll center, the roll motion of the vehicle can be reduced and the posture stability of the vehicle during turning can be improved. The jack-up angle γ _f in FIG. 5 changes due to the movement of the roll center P3 _{r due} to the movement of the suspension 10 during turning or the like. Therefore, the positional relationship between the roll center P3 _f of the front wheels 7 and the roll center P3 _r of the rear wheels 8 in FIG. 6 is based on the positional relationship when the vehicle is stopped on a horizontal plane.

<Control block diagram in this embodiment>
As shown in FIG. 7, the vehicle speed detected by the vehicle speed sensor 5, the steering angle detected by the steering angle sensor 6, the driver's accelerator operation amount detected by the accelerator pedal sensor 11, and the driving detected by the brake pedal sensor 12. The brake operation amount of the person is input to the ECU 3. In the example of FIG. 7, the ECU 3 includes a control driving force command value calculator 3a and a rear wheel steering angle command value calculator 3b. The control driving force command value calculator 3a calculates the control driving force command value based on the accelerator operation amount and the brake operation amount.

The rear wheel steering angle command value calculator 3b uses a so-called rear wheel steering angle control method in which the left and right rear wheels are steered at the same angle to the front wheels at low speed and in the same phase as the front wheels at high speed. The rear wheel steering angle command value is calculated based on. The relationship between the front wheel steering angle and the vehicle speed and the rear wheel steering angle is determined by one or both of the test and the simulation and is stored in the map or the like. Each vehicle speed at the low speed and at the high speed is arbitrarily determined. However, the vehicle speed is higher at high speed than at low speed. In the present embodiment, when the rear wheel steering angle control method is not applied, the steering angle δ _rr of the right rear wheel and the steering angle δ _rl of the left rear wheel may be considered as zero. The vehicle speed, steering angle, control driving force command value, and rear wheel steering angle command value are output from the ECU 3 to the attitude control device 4.

Based on the input vehicle speed, steering angle, control driving force command value, and rear wheel steering angle command value, the attitude control device 4 controls drive so as to perform a reference forward / backward movement, a yaw movement, and a target pitch movement. The force command value and the rear wheel steering angle command value are corrected, and the corrected control driving force command value, which is the corrected control driving force command value, is sent to the control driving force control device 13 with the corrected rear wheel steering angle command value. A certain corrected rear wheel steering angle command value is output to the rear wheel steering angle control device 2, respectively. The control driving force control device 13 controls the in-wheel motor drive device IWM (FIG. 1) according to the input corrected control drive force command value. The rear wheel steering angle control device 2 drives a rear wheel steering actuator (not shown) so that the steering angle of the rear wheels becomes the corrected rear wheel steering angle command value. The rear wheel steering actuator is driven by, for example, an electric motor or hydraulic pressure.

<Details of attitude control device>
FIG. 8 is a block diagram showing details of the attitude control device 4.
The attitude control device 4 includes a reference front-rear acceleration calculation means 23, a reference yaw rate calculation means 14, a target pitch motion setting means 15, and a command value correction means 16. In the reference longitudinal acceleration calculating means 23, serving as a reference standard longitudinal acceleration a _t the time of correcting the longitudinal force command value, the input longitudinal force command value to the posture control device 4 by (longitudinal force) equation (1) Calculate from. Reference longitudinal acceleration a _t is equal to the value obtained by dividing the sum of the longitudinal force X _i is a longitudinal force command value in vehicle weight m.

In the reference yaw rate calculating means 14, a reference yaw rate r _t which is a reference for correcting the rear wheel steering angle command value, the vehicle speed inputted to the posture control device 4, the steering angle, the rear wheel steering angle command value, the longitudinal force Calculation is performed from equations (2) and (3) using the command value.
The target pitch motion setting means 15 sets a target pitch angle or a target pitch angular velocity as a target pitch motion when correcting the control driving force command value or the rear wheel steering angle command value. These target values may be values determined based on the results of a simulation or an actual vehicle experiment, or, for example, as shown in Non-Patent Document 1, lateral acceleration generated by steering (or steering angular velocity may be used). The pitch motion according to the above may be set as in the equation (12). In Non-Patent Document 1, pitch motion is generated by generating deceleration (braking force) according to lateral acceleration. The target pitch angle can be obtained by the equation (12). The target pitch angular velocity is obtained by differentiating the equation (12).

Based on the equations (1) to (6), the command value correction means 16 sets the control driving force command value and the target driving force command value so as to obtain the reference longitudinal acceleration, the reference yaw rate, and the target pitch motion (target pitch angle or target pitch angular velocity). The rear wheel steering angle command value is corrected and output as the corrected rear wheel steering angle command value and the corrected rear wheel steering angle command value.
Here, equation (4) is the Laplace transform, the target pitch angle [Phi _t, and the longitudinal force command value and the pitch moment generated by correcting the rear wheel steering angle command value, respectively .DELTA.M _px, and .DELTA.M _py, command When the sum of the pitch moment generated by the correction value (pitch moment command value) and .DELTA.M _p becomes formula (13) to formula (16). Note that M _px and M _py are pitch moments generated by the front-rear force command value X _i before correction and the lateral force Y _i according to the steering angle command value, and the correction amount of the front-rear force command value is ΔX _i and the rear wheel steering angle. The amount of correction for δ _i is Δδ _i, and the lateral force generated by the correction is ΔY _i .

In the moment distribution means 16a in the command value correction means 16, based on the differential value (change rate: value representing the time change characteristic) of the rear wheel steering angle δ _r or the pitch moment command value ΔM _p , ΔM _px by the method described later. And ΔM _py are determined. The command value correction means 16 further calculates the correction amount of the control driving force command value and the rear wheel steering angle command value so as to substantially satisfy the reference front-rear acceleration and the reference yaw rate based on the equations (1) and (3). , The corrected driving force command value and the corrected rear wheel steering angle command value are output. In the command value correction means 16, at least the corrected driving force command value and the corrected rear wheel steering angle command value with the vehicle speed, steering angle, and controlling driving force command value as input variables are used so as to correspond to these processing procedures. The output value may be prepared as map data. In this case, the command value correction means 16 includes the processing of the reference yaw rate calculation means 14 and the target pitch motion setting means 15. Further, the processing of the rear wheel steering angle command value calculator 3b provided in the ECU 3 shown in FIG. 7 may be incorporated into the attitude control device 4 or further included in the map data.

FIG. 9 shows the steering angle, pitch angle, pitch angular velocity, pitch moment command value, differential value of pitch moment command value, corrected driving force command value, and after correction during the control operation of the attitude control device 4 (FIG. 8). It is a figure which shows the rear wheel rudder angle command value. The steering angle is positive for CCW, which is counterclockwise, the pitch angle and pitch moment command value are positive for the forward downward direction, the corrected driving force command value is positive for driving, and the corrected rear wheel steering angle command value is positive for CCW. It is said. Taking the steering angle input in the lane change operation as an example, the control driving force command value and the rear wheel steering angle command value are only for pitch control, and the control driving force command value and the rear wheel steering angle command value before correction are all zero. Is.

At the initial stage of the lane change operation (initial stage of turning), the control driving force command value and the rear wheel steering angle command value are corrected so as to satisfy the pitch moment command value at which the pitch angle becomes positive (forward downward). Distribution from the pitch moment command value ΔM _p to ΔM _px and ΔM _py is performed by the moment distribution means 16a (FIG. 8). For example, when the ratio of ΔM _py in ΔM _p is α, ΔM _px and ΔM _py are equations (21) and (22).
α = ΔM _py / ΔM _p (20)
ΔM _px = (1-α) · ΔM _p (21)
ΔM _py = α · ΔM _p (22)

The ratio α is defined, for example, as shown in FIG. 10 or FIG. The example of FIG. 9 is a case where the ratio α shown in FIG. 10 is applied. 10 and 11, moment distributor means 16a (FIG. 8), when .DELTA.M _{P_dot} a differential value of the pitch moment command value .DELTA.M _p is when the following threshold _ΔM p_dot_t a constant ratio, which exceeds the threshold _ΔM p_dot_t The ratio α is made smaller as the differential value ΔM _{p_dot} of the pitch moment command value becomes larger.

This is because when the rate of change of the pitch moment command value is large, the pitch moment is generated with good responsiveness by mainly controlling the pitch moment with the controlling driving force that can be generated with good responsiveness. When a lateral force is generated by a tire, the lateral force is generated by steering the wheel portion and deforming the ground contact portion of the tire so as to be twisted, so that the responsiveness is not good. In the case of the controlled driving force, the rigidity of the tire in the front-rear direction is high, so that the responsiveness is high, and the pitch moment can be generated with good responsiveness.

On the other hand, since the control driving force needs to be controlled according to the accelerator operation or the brake operation of the driver, it is better to mainly steer the rear wheels to generate the pitch moment. The ratio α when ΔM _{p_dot} exceeds the threshold value may be linearly decreased as the differential value of the pitch moment command value increases, as shown in FIG. 10, or the pitch moment command value as shown in FIG. As the differential value of is increased, it may be reduced in a curve as represented by an exponential function or the like. Further, in FIGS. 10 and 11, the moment distribution means 16a (FIG. 8) sets the ratio α to zero when the differential value of the pitch moment command value is equal to or greater than the maximum controllable value ΔM _{p_dot_max} . The ratio α represented by FIGS. 10 and 11 may be defined as map data in the moment distribution means 16a (FIG. 8).

As shown in FIG. 9, the correction amount of the control driving force command value is the same for the front and rear wheels, and the positive and negative directions are opposite. This is because the front-back acceleration generated by the correction is set to zero so as to match the reference front-back acceleration calculated by the equation (1) in the reference front-back acceleration calculation means 23 (FIG. 8). Further, as shown in FIG. 4, by reducing the anti-dive angle θ _f of the front wheels 7 (preferably to substantially zero) and increasing the anti-scuff angle θ _r of the rear wheels 8, the vertical movement on the front wheel side of the vehicle body is small (approximately zero). ), Which makes it easier to control the vertical movement on the rear wheel side.

With such a vehicle configuration, it becomes easy to control the vertical movement of the rear wheel side of the vehicle body by both the control driving force and the rear wheel steering angle. The rear wheel steering angle command value is corrected so that the rear wheel side of the vehicle body is lifted at the initial stage of turning. This correction amount may be the same for the left and right wheels, but it is desirable that the correction amount for the turning outer ring is smaller than that for the turning inner ring. Load transfer occurs due to the generation of lateral acceleration due to turning, and the ground contact load of the tire is larger for the right wheel, which is the turning outer ring, than for the left wheel, which is the turning inner ring, and the amount of change in lateral force and lateral force when the steering angle is changed. This is because the change in the vertical force generated in the vehicle body due to the force becomes large.

In the plane motion of the vehicle represented by the equations (2) and (3), in order to make the vehicle motion before and after the correction of the rear wheel steering angle command value approximately equal, the sum of the lateral forces generated by the rear wheels is approximately equal. There is a need. By reducing the correction amount of the turning outer wheel and making the magnitude of the lateral force that changes between the left and right rear wheels by the correction approximately equal, the vehicle motion before and after the correction of the rear wheel steering angle command value can be approximately equalized.

Next, in the scene where the steering angle is reduced, the rear wheel steering angle command values of the left and right rear wheels are corrected so that the pitch angle becomes negative (front rising), and the rear wheel side of the vehicle body is lowered. The same operation is performed when the steering angle is increased in the negative direction (CW). By correcting the rear wheel steering angle command value and generating pitch motion in accordance with the driver's steering, the driving operability of the vehicle is improved.

<Action effect>
According to the vehicle attitude control device 4 described above, the command value correction means 16 has a control driving force command value and a rear wheel rudder so that the vehicle body motion substantially matches the reference front-rear acceleration, the reference yaw rate, and the target pitch motion. Correct the angle command value. In other words, by calculating the target pitch angle or target pitch angular velocity that is the target pitch motion according to the steering angle and vehicle speed, and correcting the control driving force command value and the rear wheel steering angle command value of the front and rear wheels 7 and 8. A pitch moment is freely generated in the vehicle body, and the pitch motion is controlled so as to substantially match one of the target values. Diagonal, that is, a diagonal change in posture, which is a combination of this pitch movement and the roll movement generated by turning, realizes steering with a margin for the driver, thereby improving the driving operability of the driver's steering. it can.

In this case, the moment distribution means 16a in the command value correction means 16 sets the sum total ΔM _p of the pitch moments generated by the correction as the pitch moment ΔM _px generated by the correction of the control driving force command value, and the rear wheel steering angle command value. It is distributed to the pitch moment ΔM _py generated by the correction of. This moment distribution means 16a is for setting the magnitude of the moment based on the value representing the time variation characteristics of the pitch moment ΔM value representing a time variation characteristic of the _p or the rear wheel steering angle command value [delta] _r,, distributes, A component that changes quickly can be generated by the driving force, and a component that changes slowly can be generated by the steering angle of the rear wheels.

When the time change characteristic of the pitch moment ΔM _p or the rear wheel rudder angle command value δ _r is large, the pitch moment is responsive mainly by controlling the pitch moment by the controlling driving force that can be generated with good responsiveness. This is to generate it with good sex. When a lateral force is generated by a tire, the lateral force is generated by steering the wheel portion and deforming the ground contact portion of the tire so as to be twisted, so that the responsiveness is not good. In the case of the controlled driving force, the rigidity of the tire in the front-rear direction is high, so that the responsiveness is high, and the pitch moment can be generated with good responsiveness. Therefore, the responsiveness in pitch motion control can be improved.

<About other embodiments>
In the following description, the same reference numerals will be given to the parts corresponding to the matters previously described in each embodiment, and duplicate description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described above unless otherwise specified. It has the same effect from the same configuration. In addition to the combination of the parts specifically described in each embodiment, it is also possible to partially combine the embodiments as long as the combination does not cause any trouble.

As another example of the ratio α, as shown in FIG. 12, the moment distribution means 16a (FIG. 8) uses a differential value (rate of change: a value representing the time change characteristic) δ _{r_dot} of the rear wheel steering angle command value. The magnitude of the moment to be distributed may be set. In this case, as in FIG. 11, when the rate of change δ _{r_dot} of the rear wheel steering angle command value is _{equal to} or less than the threshold value δ _{r_dot_t,} a constant ratio is set, and when the threshold value δ _{r_dot_t} is exceeded, the differential value δ _{r_dot} of the rear wheel steering angle command value is The larger the value, the smaller the ratio α. Further, in the moment distribution means 16a (FIG. 8), the ratio α is set to zero when the differential value of the rear wheel steering angle command value is equal to or more than the controllable maximum value δ _{r_dot_max} in the differential value of the rear wheel steering angle.

As shown in FIG. 13, in the moment distribution means 16a, the pitch moment command value ΔM _p may be distributed to the high frequency component and the low frequency component by the low-pass filter 16aa, and the high frequency component may be ΔM _px and the low frequency component may be ΔM _py .

FIG. 14 shows a rear wheel steering angle command in the example of FIG. 9 when a rear wheel steering control method for steering the left and right rear wheels at the same angle in the opposite phase to the front wheels at low speed and in the same phase as the front wheels at high speed is applied. It is a figure which shows the example of correcting a value. FIG. 14 shows a case where the rear wheel steering angle command value before correction is in phase with the steering angle of the front wheels and is steered with the same magnitude on the left and right wheels during high-speed driving.

FIG. 15 is a diagram showing a case where only the pitch motion that lowers forward is applied in the example of FIG. When a pitch motion that lowers the front is generated by lifting the rear wheel side of the vehicle body, the pitch motion occurs with the front wheel side of the vehicle body as a fulcrum. For this reason, the driver's body is generated with a force that is pressed against the seat, and the body is in close contact with the seat, so that the driver can feel secure. On the other hand, when the rear wheel side of the vehicle body is lowered to generate a pitch motion, a force is generated on the driver's body to pull it away from the seat, which may reduce the driver's sense of security.

Therefore, the command value correction means 16 (FIG. 8) corrects the control driving force command value and the rear wheel steering angle command value so that only the pitch motion that lowers forward is generated by lifting the rear wheel side of the vehicle body. Is good. In this case, it is desirable that the vehicle has a suspension in which the vertical force generated through the suspension due to the controlling driving force of the front wheels becomes substantially zero. In this case, the anti-dive angle can be set to substantially zero, which facilitates control of only the vertical movement on the rear wheel side of the vehicle body.

In each of the above-described embodiments, the in-wheel motor drive device IWM is used to generate the control drive force. However, the control drive force may act as a vertical force of the vehicle body via the suspension, for example, a friction brake. The braking force due to the above or the driving force due to the engine, the motor-on-board type electric motor or the like may be transmitted via the joint.
In the in-wheel motor drive device IWM, a cycloid type speed reducer, a planetary speed reducer, and other speed reducers can be applied, and a direct motor type that does not use a speed reducer may be used.

Although the embodiments for carrying out the present invention have been described above based on the embodiments, the embodiments disclosed this time are exemplary in all respects and are not limiting. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

2 ... Rear wheel steering angle control device, 4 ... Attitude control device, 5 ... Vehicle speed sensor (vehicle speed detection means), 6 ... Steering angle sensor (steering angle detection means), 7 ... Front wheels, 8 ... Rear wheels, 9, 10 ... Suspension, 11 ... Accelerator pedal sensor (accelerator operation amount detecting means), 12 ... Brake pedal sensor (brake operation amount detecting means), 13 ... Control driving force control device, 14 ... Reference yaw rate calculation means, 15 ... Target pitch motion setting means , 16 ... Command value correction means, 16a ... Moment distribution means, 23 ... Reference front-rear acceleration calculation means

Claims (10)

Vehicle speed detecting means for detecting the speed of the vehicle, steering angle detecting means for detecting the steering angle of the front wheels, accelerator operating amount detecting means for detecting the accelerator operating amount of the accelerator operating means of the vehicle, braking operation of the brake operating means of the vehicle. Brake operation amount detecting means for detecting the amount, control driving force control device capable of adjusting the braking force or driving force of the left and right front and rear wheels, and rear wheel steering angle control capable of adjusting the steering angle of the rear wheels. An attitude control device that controls the attitude of a vehicle equipped with the device.
In the vehicle, a pitch moment is generated in the vehicle body by a vertical force acting on the vehicle body via the suspensions of the front and rear wheels by the control driving force adjusted by the control driving force control device, and the rear wheel steering angle control is performed. A vehicle in which a pitch moment is generated in the vehicle body by a vertical force acting on the vehicle body via the suspension of the rear wheels by adjusting the steering angle of the rear wheels with a device and generating a lateral force in the rear wheels.
Based on the accelerator operation amount and the brake operation amount, the control driving force command value of each wheel is calculated, and the reference front-rear acceleration calculation means for calculating the reference front-rear acceleration of the vehicle from the control drive force command value,
A reference yaw rate calculating means for calculating a reference yaw rate of the vehicle based on the vehicle speed detected by the vehicle speed detecting means, the steering angle, and a rear wheel steering angle command value given according to a predetermined condition.
A target pitch motion setting means for setting a target pitch angle or a target pitch angular velocity to be a target pitch motion based on the vehicle speed, the steering angle, and the rear wheel steering angle command value.
A command value correction means for correcting the control driving force command value and the rear wheel steering angle command value so that the vehicle body motion substantially matches the reference front-rear acceleration, the reference yaw rate, and the target pitch motion.
The command value correction means adds the sum of the pitch moments generated by the correction of the control driving force command value and the rear wheel steering angle command value to the pitch moment generated by the correction of the control driving force command value and the rear. It has a moment distribution means that distributes to the pitch moment generated by the correction of the wheel steering angle command value.
This moment distribution means obtains a value representing the time change characteristic of the pitch moment generated by correcting the control driving force command value and the rear wheel steering angle command value, or a time change characteristic of the rear wheel steering angle command value. The magnitude of the distributed moment is set based on the value to be represented.
Vehicle attitude control device. In the attitude control device for a vehicle according to claim 1, wherein the moment distribution means, the braking and driving force command value and the differential value of the pitch moment .DELTA.M _p generated by correcting the rear wheel steering angle command value, or the A vehicle attitude control device that sets the magnitude of the moment to be distributed based on the differential value of the rear wheel steering angle command value δ _r . In the attitude control system according to claim 2, wherein the moment distribution means, the magnitude of the differential value of the pitch moment .DELTA.M _p, or a magnitude threshold of the differential value of the rear wheel steering angle command value [delta] _r when it exceeds, the attitude control device for a vehicle to reduce the distribution ratio of the pitch moment .DELTA.M _py generated by the correction of the rear wheel steering angle command value. In the attitude control system according to claim 2 or claim 3, wherein the moment distributor means, the magnitude of the differential value of the pitch moment .DELTA.M _p, or the size of the differential value of the rear wheel steering angle command value [delta] _r A vehicle attitude control device that _sets the distribution ratio to the pitch moment ΔM _py generated by the correction of the rear wheel steering angle command value to zero when the value exceeds the threshold value. In the attitude control device for a vehicle according to claim 1, wherein the moment distribution means on the basis of the frequency characteristics of the pitch moment .DELTA.M _p, attitude control device for a vehicle that sets the magnitude of the moment the distribution. In the attitude control device for a vehicle according to claim 5, wherein the moment distributor means distributes a low-frequency component of the pitch moment .DELTA.M _p as pitch moment .DELTA.M _py generated by the correction of the rear wheel steering angle command value, the A vehicle attitude control device that distributes a pitch moment excluding low-frequency components as a pitch moment ΔM _px generated by correcting the control driving force command value. In the attitude control device for a vehicle according to any one of claims 1 to 6, the command value correction means causes the vehicle to perform a pitch motion in a forward-down direction by at least lifting the rear wheel side of the vehicle body. A vehicle attitude control device that makes the correction so as to occur. In the vehicle attitude control device according to any one of claims 1 to 7, the vehicle passes through the suspensions of the front and rear wheels when the magnitudes of the controlling driving force of the front wheels and the rear wheels are equal. With respect to the vertical force acting on the vehicle body, when the rear wheels are larger than the front wheels and the steering angles of the front wheels and the rear wheels are equal, the lateral force generated by the tires causes the suspension to pass through the suspension. A vehicle attitude control device having a suspension in which the rear wheels are larger than the front wheels with respect to the vertical force acting on the vehicle body. In the vehicle attitude control device according to claim 8, the vehicle is a vehicle attitude control device in which the height of the roll center position of the front wheels is substantially equal to the ground position. The attitude control device for a vehicle according to claim 8 or 9, wherein the vehicle has a suspension in which the anti-dive angle of the front wheels is substantially zero.

Images