JP3082580B2 - Alignment control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment control device for a vehicle suspension system, and aims at reducing the amount of steering and improving convergence during steering.

[0002]

2. Description of the Related Art Conventionally, there has been known a vehicle suspension device including an actuator for changing an arm length of a specific suspension arm, a vehicle body mounting position, and the like, and a controller for controlling the actuator. When the controller drives the actuator, the positional relationship between the arms and struts of the suspension device changes, and therefore, the alignment of the suspension device, that is, the caster angle and trail of the suspension device, the toe angle and camber angle of the wheel, and the like. Changes. The controller positively operates the alignment according to the running state of the vehicle to improve the straight running stability and the turning stability of the vehicle.

[0003] The caster angle is extremely important in terms of steering performance and running stability. When the caster angle is increased, the restoring moment for returning to the straight running position when the wheels deviate from the straight running position during running increases. As a result, the running stability during high-speed running is improved. Therefore, conventionally, an alignment control method has been proposed in which the caster angle is made variable in accordance with the vehicle speed, that is, the caster angle is increased during high-speed running, and the caster angle is reduced during medium-to-low speed running (Japanese Patent Laid-Open No. Sho 5).
No. 9-67111). By making the caster angle variable according to the vehicle speed, it is easy to steer at the time of middle and low speed running, and the response of steering at the time of high speed running is obtained.
Steering performance and high-speed running stability are improved.

[0004]

In the conventional alignment control method, the running stability of the vehicle is improved by varying the caster angle even when the vehicle is running at a low speed or at a high speed. . However, although the caster angle is variable, it is set so that the wheels are in an understeer state when the steering wheel is steered. For this reason, when traveling on a curved road, the steering amount of the steering wheel is increased, and the turning performance seen from the driver side is suppressed, and the turning performance particularly in the medium speed range is sacrificed, and the traveling on the curved road is performed. Had a drawback in the ease of bending. In addition, in terms of ease of turning and stability (convergence) of the vehicle in transient situations, an increase in the equivalent cornering power at the front is effective, but when the wheels are understeered, the equivalent cornering power is reduced. And there was also a drawback in astringency.

The present invention has been made in view of the above circumstances, and has as its object to provide an alignment control device capable of reducing the amount of steering during steering and improving convergence.

[0006]

According to the present invention, there is provided an actuator for changing a caster angle of a wheel, driving means for operating the actuator, and a target based on a running state of the vehicle. Control means for calculating the caster angle to be operated and operating the actuator so that the actual caster angle becomes the target caster angle, and one end of the tie rod is connected to the wheel,
In the suspension alignment control device in which the other end of the tie rod is connected to a steering mechanism, when the wheel is set to a caster angle larger than a reference caster angle by operation of the actuator by the control means, the rolling of the vehicle is controlled. The wheels are over-steered as the suspension moves up and down.

Further, according to the present invention, there is provided an actuator for changing a caster angle of a wheel, driving means for operating the actuator, and a caster angle which is set based on a running state of the vehicle. And control means for operating the actuator so that the actual caster angle becomes the target caster angle, and one end of the tie rod is connected to the wheel, and the other end of the tie rod is connected to the steering mechanism. In the suspension alignment control device, the vehicle-side connection point, which is a connection point between the tie rod and the wheel, and the vehicle-side connection point, which is a connection point between the tie rod and the steering mechanism, are the actuators controlled by the control means. When the wheels are set to the reference caster angle by the operation of The wheel-side connection point moves upward with the up-and-down movement of the pension, and the wheels enter an understeer state. On the other hand, when the actuator is actuated by the control means, the caster angle is larger than the caster angle at which the wheels are referenced. When set to, the wheel-side connection point is located below the wheel-side connection point when set to the reference caster angle, with the vertical movement of the suspension during rolling of the vehicle The wheel-side connection point moves upward, and the wheel enters an oversteer state.

When the wheel is set at the reference caster angle, the wheel-side connection point and the vehicle-side connection point are positioned substantially in a horizontal state, and the wheel is set at a position higher than the reference caster angle. When the caster angle is also set to a large caster angle, the wheel-side connection point is located below the vehicle-side connection point in the horizontal direction, and with the vertical movement of the suspension during rolling of the vehicle, the wheel-side connection point The connection point is on the upper side, and is lower than the position of the wheel-side connection point when the wheel is moved to the upper side when the wheel is set to the reference caster angle and the wheel enters the understeer state. And the wheels are over steered.

The reference caster angle is set according to the vehicle speed, and when the reference caster angle is set at the reference caster angle, the wheels understeer as the suspension moves up and down during rolling of the vehicle. The caster angle is a region in which the caster angle is set to be larger than the reference caster angle when the steering wheel angular velocity and the lateral acceleration are considered.

[0010]

[Function] The caster angle is changed according to the running state of the vehicle,
When the wheels are set at a caster angle larger than the reference caster angle, the wheels are over-steered as the suspension moves up and down during rolling of the vehicle. At this time, by setting the wheel to a caster angle larger than the reference caster angle in consideration of the steering wheel angular velocity and the lateral acceleration, the wheel is over-steered when traveling on a curved road. When the wheel is set at a caster angle larger than the reference caster angle, the wheel-side connection point is located at the lower side, so that the wheel-side connection point is associated with the vertical movement of the suspension during rolling of the vehicle. Moves upward and enters an understeer state when set to a reference caster angle, and enters an oversteer state when set to a caster angle larger than the reference caster angle.

[0011]

1 is a schematic configuration of an alignment control apparatus according to one embodiment of the present invention. FIG. 2 is a plan view of the alignment control apparatus when a caster angle is set as a reference.
5 is a view taken in the direction of the arrow III in FIG. 2, and FIG. 4 is a view taken in the direction of the arrow IV in FIG.
FIG. 6 is a plan view of the alignment control device when the caster angle is set to be larger than the reference caster angle, FIG. 6 is a view taken along a line VI in FIG. 5, and FIG. 7 is a view taken along a line VII in FIG. is there. The suspension device 1 is, for example, a multi-link type suspension device in which left and right front and rear wheels are respectively connected to a vehicle body (not shown). The figure shows a suspension device 1 for connecting, for example, a left front wheel (hereinafter referred to as a wheel) 2 to a vehicle body side.

As shown in FIG. 1, a suspension device 1
A knuckle 3 for rotatably supporting the wheel 2 and an upper arm 4 for connecting the extension 3a of the knuckle 3 to the vehicle body side.
And lower arms 5, 6 for connecting the lower end of the knuckle 3 to the vehicle body side. An actuator 7 is interposed between the lower arm 5 and the vehicle body, and the caster angle θ of the wheel 2 is set to a desired angle by the operation of the actuator 7. The hydraulic pressure is supplied to the actuator 7 from a hydraulic pressure source 9 by switching a flow control valve (electromagnetic valve) 8, and the electromagnetic valve 8 is switched based on a control voltage commanded by an ECU 10 as control means. That is, the driving means is constituted by the solenoid valve 8 and the hydraulic pressure source 9. Information from a vehicle speed sensor 11, a steering wheel angle sensor 12, a left / right acceleration sensor (left / right G sensor) 13, and a longitudinal acceleration sensor (longitudinal G sensor) 14 is input to the ECU 10. In the ECU 10,
Based on the information obtained from these sensors 11 to 14, the steering wheel angle, the steering wheel angular velocity, the longitudinal G, the lateral G, and the lateral acceleration are calculated and read (calculated lateral g). The ECU 10 calculates and reads a road surface friction coefficient (road surface μ) based on the hydraulic pressure of a power steering device (not shown). The ECU 10 calculates a target caster angle as a target based on the steering wheel angle, the steering wheel angular velocity, the longitudinal G, the lateral G, the calculated lateral g, and the road surface μ, and operates the actuator 7 so that the caster angle θ becomes the target caster angle. From the ECU 10 to the solenoid valve 8
Is output to the control command.

As shown in FIGS. 2 to 7, the knuckle 3 is provided with a knuckle arm 3b.
Extends rearward with respect to the kingpin axis α. One end 21a of the tie rod 21 is connected to the knuckle arm 3b, and the other end 21b of the tie rod 21 is connected to a steering mechanism (not shown). A connection point H (hereinafter, referred to as H point) between one end 21a of the tie rod 21 and the knuckle arm 3b is a wheel-side connection point, and a connection point T (hereinafter, referred to as T point) between the other end 21b of the tie rod 21 and the steering mechanism is on the vehicle side. It is a connection point.

As shown in FIGS. 2 to 4, when the caster angle is set to a reference angle (for example, 5 degrees), at normal vehicle height where the vehicle does not perform rolling, points H and T are set. Are positioned substantially horizontally (indicated by dotted lines in the figure). In this state, the H point of the tie rod 21 moves upward together with the vertical movement (pressure side) of the suspension due to the rolling of the vehicle (shown by a solid line in FIG. 4), and the H point of the tie rod 21 is further inside the kingpin axis α. Move to. For this reason, the toe angle of the wheel 2 changes to the out side (change from the dotted line state to the solid line state in FIG. 2), and the wheel 2 enters the understeer state.

As shown in FIGS. 5 to 7, the caster angle is larger than the reference angle (for example, 8 degrees).
When the vehicle is set at the normal vehicle height where the vehicle does not perform rolling, the point H is located below the point T in the horizontal direction (indicated by a dotted line in the figure). In this state, the H point of the tie rod 21 moves upward together with the vertical movement (pressure side) of the suspension due to rolling of the vehicle (shown by a solid line in FIG. 7), and the H point of the tie rod 21 further moves to the kingpin axis α side. I do. In addition, the H point at this time is a position lower than the height of the H point that has moved upward when the caster angle is set to 5 degrees. For this reason, wheel 2
Changes from the dotted line state to the solid line state in FIG. 5), and the wheel 2 enters the oversteer state.

The state shown in FIG. 2 to FIG.
3. Further, the present invention is not limited to the above-described state, and the wheel 2 is set to be in an oversteer state in accordance with the vertical movement of the suspension during rolling of the vehicle when the caster angle is 8 degrees. is there.

Next, with reference to FIG. 8, a description will be given of the roll steer characteristic of the suspension described above, that is, the roll steer characteristic in which the front wheels are steered by rolling when the steering wheel is steered. FIG. 8 shows the relationship between the roll angle and the toe angle with respect to the caster angle, that is, the roll steer characteristic. As shown by the dashed line in FIG. 8, when the caster angle is 5 degrees (in the case shown in FIGS. 2 to 4), as the roll angle (deg) of the vehicle increases, the outer wheel 2 The toe angle (deg) changes to the understeer side. As shown by the solid line in FIG. 8, when the caster angle is 8 degrees (the case shown in FIGS. 5 to 7), the roll angle (de
g) increases, the toe angle (de
g) changes to the oversteer side. In addition, as shown by the two-dot chain line in FIG. 8, when the caster angle is 1.1 degrees, as the roll angle (deg) of the vehicle increases, the outer wheels 2
The toe angle (deg) greatly changes toward the understeer side. Thus, by changing the caster angle, the wheels 2
Understeer control and oversteer control can be performed.

Next, the setting state of the caster angle in the above-mentioned suspension will be described with reference to FIGS. FIG. 9 is a control flowchart of the alignment control device for setting the caster angle, FIG. 10 is a map of the caster angle with respect to the vehicle speed (km / h), and FIG.
/ s) map of caster angle, FIG.
The map of the caster angle with respect to is shown.

As shown in FIG. 9, in step S1, various coefficients are set with preset initial values (initial setting), and in step S2, the values of the respective sensors are read. In step S3, a vehicle speed control caster angle θ0, which is a caster angle with respect to the vehicle speed (km / s), is obtained from the map (vehicle speed map) shown in FIG. Next, step S
In step 4, the caster angle increment Δθ1 with respect to the steering wheel angular velocity (deg / s) is determined from the map (vehicle speed-handle angular velocity map) shown in FIG. Further, in step S5, the caster angle increase amount Δθ2 on the turning outer wheel side is obtained from the map (calculated lateral g map) shown in FIG. Vehicle speed control caster angle θ0,
After obtaining the caster angle increments Δθ1 and Δθ2, it is determined in step S6 whether the vehicle is turning left. That is, when the product of the steering wheel angle and the lateral acceleration is a positive value, it is determined that the vehicle is turning left, and when the product of the steering wheel angle and the lateral acceleration is a negative value, it is determined that the vehicle is turning right. If it is determined in step S6 that the vehicle is turning left, in step S7, the caster angle θL of the left front wheel on the inner wheel side and the caster angle θR of the right front wheel on the outer wheel are calculated by the following equation. θL = θ0 + Δθ1 θR = θ0 + Δθ1 + Δθ2 If it is determined in step S6 that the vehicle is turning right, step S8
Then, the caster angle θL of the left front wheel on the turning outer wheel side and the caster angle θR of the right front wheel on the turning inner wheel are calculated by the following equations. θL = θ0 + Δθ1 + Δθ2 θR = θ0 + Δθ1

The vehicle speed map shown in FIG. 10 will be described. The vehicle speed control caster angle θ0 is set to increase as the vehicle speed (km / h) increases, and the maximum value of the vehicle speed control caster angle θ0 is about 140 km / h, which is approximately 6 degrees. As can be seen in FIG. 8, the toe angle (deg) of the wheel 2 hardly changes even when the roll angle (deg) of the vehicle increases, and the vehicle speed control caster angle set by the vehicle speed θ0
Is an area where the wheels 2 enter an understeer state as the suspension moves up and down during rolling of the vehicle. That is, the vehicle speed control caster angle θ0 set according to the vehicle speed is the reference caster angle. The vehicle speed control caster angle θ0 is set to a small value in the low speed range (0 km / h to about 25 km / h) to reduce the steering burden, and
At about 35 km / h to about 75 km / h), the base value (for example, 5
(Degrees) to reduce the sensitivity to disturbance input. In the high-speed range (about 100 km / h or more), it is set near the maximum value to improve the straight running stability.

The map vehicle speed-handle angular velocity map shown in FIG. 11 will be described. The caster angle increment Δθ1 is the vehicle speed
(km / h) reaches approximately 45km / h until the steering wheel angular velocity (deg.
/ s) is set to increase according to the magnitude of the vehicle speed.
(km / h) is set to a constant value from about 45 km / h to about 60 km / h. Thereafter, the caster angle increase amount Δθ1 is set to gradually decrease as the vehicle speed (km / h) increases. In other words, the steering wheel angular velocity (deg /
When s) increases, the caster angle increase amount Δθ1 corresponding to the magnitude of the steering wheel angular velocity (deg / s) is added to the reference caster angle. For this reason, the caster angle is increased, for example, when traveling on a curved road in the middle speed range, and the wheel 2 becomes in an oversteer state as the suspension moves up and down during rolling of the vehicle. The goodness has been improved.

The calculated horizontal g map shown in FIG. 12 will be described. The caster angle increment Δθ2 is calculated in both the left and right directions.
Is set so as to increase with the increase of the caster angle when the calculated lateral g increases.
The caster angle is added to the reference caster angle for the wheel 2 on the turning outer wheel side. Therefore, steering response and turning limit are improved.

In this manner, based on the vehicle speed (km / h), the steering wheel angular velocity (deg / s) and the calculated lateral g, the caster angle increments Δθ1 and Δθ2 based on the vehicle speed-steering wheel angular velocity map and the calculated lateral g map are calculated as follows: Reference vehicle speed control caster angle θ
By taking this into account, the caster angle of the wheels 2 during traveling is set according to the traveling state. By adding the caster angle increments Δθ1 and Δθ2 to the reference vehicle speed control caster angle θ0, the caster angle is set to be larger than the reference caster angle, and the vertical movement of the suspension during rolling of the vehicle occurs. As a result, an area in which the wheels 2 are in an oversteer state is established (claim 4).

In the above-described alignment control device, when the vehicle travels straight, the steering wheel angular velocity (deg / s) and the calculated lateral g are substantially zero, so that the caster angles do not take into account the caster angle increments Δθ1 and Δθ2. The vehicle speed is controlled by a reference vehicle speed control caster angle θ0. That is, based on the vehicle speed map, the vehicle speed control caster angle θ0 is increased as the vehicle speed (km / h) increases, and the vehicle speed (km) is set in an area where the wheels 2 are in an understeer state as the suspension moves up and down during rolling of the vehicle. / h), the caster angle is set. For this reason, the caster angle is set to a small value in a low speed range to reduce the steering burden, and is set to a base value (for example, 5 degrees) in a medium speed range to reduce the sensitivity to disturbance input. It is set near the maximum value to improve the straight running stability.

When the vehicle travels on a curved road, the vehicle speed control caster angle θ0 is determined based on the vehicle speed map.
h) increases and the steering wheel angular velocity (deg.
/ s) and the caster angle increase Δθ according to the situation of the calculated lateral g
1, Δθ2 is controlled in consideration of the vehicle speed control caster angle θ0. That is, based on the vehicle speed map, the vehicle speed control caster angle θ0 is increased with an increase in the vehicle speed (km / h). At that time, if the steering wheel angular speed (deg / s) and the calculated lateral g increase, the caster angle increase by that amount Δθ1 and Δθ2 are added to the vehicle speed control caster angle θ0, so that the caster angle is increased even in the middle to low speed range. Therefore, as can be seen from FIG. 8, the caster angle is set in a region where the wheels 2 are in an oversteer state as the suspension moves up and down during rolling of the vehicle. Wheel 2 when caster angle is increased
In the oversteer state, the equivalent cornering power is increased, and the bendability and good fit are improved.

FIG. 13 shows the state of the steering wheel angle (deg) when traveling on a curved road at a vehicle speed of 70 km / h when the above-described alignment control device is used (shown by a solid line in the figure) and the caster angle. Is fixed at 5 degrees (indicated by a dashed line in the figure). As shown in FIG. 13, the steering angular velocity (deg.
/ s) and the caster angle increase Δθ according to the situation of the calculated lateral g
When the caster angle is increased during cornering by adding 1, Δθ2 to the vehicle speed control caster angle θ0, the wheels 2 are over-steered as the suspension moves up and down during rolling of the vehicle, so the caster angle was fixed at 5 degrees. The steering wheel angle (deg) may be smaller than in the case. Therefore, the steering amount is reduced by this amount, and the bendability is improved. Further, FIG. 14 shows the results of the steering transient response characteristics when the steering wheel is steered in an impulse manner at a vehicle speed of 100 km / h, and the caster angle when the above-described alignment control device is used (shown by a solid line in the figure). The case of fixing at 5 degrees (indicated by a dashed line in the figure) and the case of fixing at 1.1 degrees (indicated by a dashed line in the figure) are shown in comparison. As shown in FIG. 14, the caster angle is calculated by adding the steering wheel angular velocity (deg / s) and the caster angle increments Δθ1 and Δθ2 according to the situation of the calculated lateral g to the vehicle speed control caster angle θ0 using the alignment control device. When it is increased, the turning property (yaw rate gain), damping property (yaw rate damping ratio), and quick response (yaw rate natural frequency) become larger values than when the caster angle is fixed to 5 degrees and when the caster angle is fixed to 1.1 degrees. Become. For this reason, it is understood that the bendability and the goodness of fit (convergence) are improved, and the responsiveness is excellent.

In the above-described alignment control device, when the steering wheel angular velocity (deg / s) and the calculated lateral g are small during high-speed running, the wheels 2 are in an understeer state with a large caster angle, so that the running stability and steering response are improved. You can get the feeling. Also, when driving at medium to low speeds, the steering wheel angular velocity (deg.
/ s) and the calculated lateral g increase, that is, when traveling on a curved road, in addition to the vehicle speed control caster angle θ0, the steering wheel angular velocity (deg / s) and the caster angle increase Δθ1, Since the caster angle is increased by Δθ2 to cause the wheels 2 to be in an oversteer state as the suspension moves up and down during rolling of the vehicle, the steering amount is reduced, and the ease of turning and the convergence can be improved. For this reason, the straight running stability at the time of high-speed running can be improved, and the kinetic performance at the time of medium-low speed running can be improved, so that the straight running stability and the kinetic performance can be compatible at a high level. Also, handle angular velocity (deg
/ s) and the calculation value g is set to the caster angle of the region where the wheel 2 is in the oversteer state when the lateral width g is large, so that the maximum value of the vehicle speed control caster angle θ0 in the region where the wheel 2 is in the understeer state is set. It is possible to set a large value, and the straight running stability performance during high-speed running can be significantly improved.

[0028]

According to the alignment control apparatus of the present invention, when the wheels are set at a caster angle larger than the reference caster angle, the wheels are over-steered with the vertical movement of the suspension during rolling of the vehicle. Therefore, by setting the caster angle to be larger than the reference caster angle according to the steering, the steering amount at the time of traveling on a curved road is reduced, and the equivalent cornering power is increased,
Bending easiness and convergence can be improved, and the kinetic performance during low-speed running is improved. Also, the reference caster angle is set according to the vehicle speed, and when the reference caster angle is set, the wheel is in an understeer state as the suspension moves up and down during rolling of the vehicle, Straight running stability during high-speed running can be improved. As a result, the straight running stability at the time of high-speed running can be improved, and the kinetic performance at the time of medium-low speed running can be improved, so that the straight running stability and the kinetic performance can be compatible at a high level.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an alignment control device according to an embodiment of the present invention.

FIG. 2 is a plan view of the alignment control device when a reference caster angle is set.

FIG. 3 is a view taken in the direction of the arrow III in FIG. 2;

FIG. 4 is a view taken in the direction of the arrow IV in FIG. 2;

FIG. 5 is a plan view of the alignment control device when the caster angle is set to be larger than a reference caster angle.

FIG. 6 is a view taken in the direction of arrow VI in FIG. 5;

FIG. 7 is a view taken in the direction of arrow VII in FIG. 5;

FIG. 8 is a graph showing roll steer characteristics.

FIG. 9 is a control flowchart of an alignment control device for setting a caster angle.

FIG. 10 is a map of a caster angle with respect to a vehicle speed.

FIG. 11 is a map of a caster angle with respect to a steering wheel angular velocity.

FIG. 12 is a map of a caster angle with respect to a calculated lateral acceleration.

FIG. 13 is a graph showing a state of a steering wheel angle when traveling on a curved road.

FIG. 14 is a graph showing a result of a steering transient response characteristic.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Suspension device 2 Wheel 3 Knuckle 4 Upper arm 5, 6 Lower arm 7 Actuator 8 Flow control valve (solenoid valve) 9 Hydraulic power source 10 ECU 11 Vehicle speed sensor 12 Handle angle sensor 13 Left and right G sensor 14 Front and rear G sensor 21 Tie rod H point Wheel side connection Point T Point Vehicle side connection point

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-87844 (JP, A) JP-A-6-171334 (JP, A) JP-A-60-4407 (JP, A) JP-A-59-1984 67111 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60G 17/015 B62D 7/08

Claims (4)

(57) [Claims] An actuator for changing a caster angle of a wheel, a driving means for operating the actuator, a target caster angle calculated based on a running state of a vehicle, and an actual caster angle set to the target caster angle. Control means for operating the actuator so as to form an angle, wherein one end of the tie rod is connected to a wheel, and the other end of the tie rod is connected to a steering mechanism. When the wheel is set to a caster angle larger than a reference caster angle by operation of the actuator, the wheel is over-steered as the suspension moves up and down during rolling of the vehicle. Control device. 2. An actuator for changing a caster angle of a wheel, driving means for operating the actuator, and a caster angle which is a target caster angle is calculated based on a running state of a vehicle, and an actual caster angle is set to the target caster angle. Control means for operating the actuator so as to form an angle, wherein one end of the tie rod is connected to a wheel, and the other end of the tie rod is connected to a steering mechanism. A wheel-side connection point, which is a wheel-side connection point, and a vehicle-side connection point, which is a connection point between the tie rod and the steering mechanism, are set to caster angles on which the wheels are referenced by the operation of the actuator by the control means. When the vehicle is rolling, the wheel-side connection point When the wheel is set to a caster angle larger than a reference caster angle by operating the actuator by the control means while the wheel is moved upward and the wheel is in an understeer state, the wheel-side connection point is The wheel-side connection point is located below the wheel-side connection point when set to a reference caster angle, and the wheel-side connection point moves upward with the vertical movement of the suspension during rolling of the vehicle. An alignment control device, wherein the wheels are in an oversteer state. 3. When the wheel is set to the reference caster angle, the wheel-side connection point and the vehicle-side connection point are located in a substantially horizontal state, and the wheel is set at a position higher than the reference caster angle. When the caster angle is also set to a large caster angle, the wheel-side connection point is located below the vehicle-side connection point in the horizontal direction, and with the vertical movement of the suspension during rolling of the vehicle, the wheel-side connection point The connection point is on the upper side, and is lower than the position of the wheel-side connection point when the wheel is moved to the upper side when the wheel is set to the reference caster angle and the wheel enters the understeer state. 3. The alignment control device according to claim 2, wherein the wheel is moved to an oversteer state. 4. The reference caster angle is set according to the vehicle speed. When the reference caster angle is set at the reference caster angle, the wheel understeers as the suspension moves up and down during rolling of the vehicle. The caster angle is a region in which the caster angle is set to be larger than the reference caster angle when the steering wheel angular velocity and the lateral acceleration are taken into account.
3. The alignment control device according to 1.