JPH05105101A - Front and rear wheel steering control device - Google Patents

Abstract

PURPOSE:To enhance the cornering performance in the critical running zone by controlling the auxiliary steering angle with the sum of the steering angle feed-forward term and the yawrate feedback term, and at the same time, changing the gain of one of the terms in the direction in which the yaw moment increases in accordance with the magnitude of the lateral acceleration. CONSTITUTION:Using a means (a), the auxiliary steering angle is given to at least one of the front wheels and rear wheels not by means of the steering force from a steering wheel but in conformity to a command given externally. The steering angle due to steering wheel, yawrate, and lateral acceleration are sensed by respective means (b, c, d). At least one of the feedback gain and feed-forward gain is set by a means (e) in the direction in which the yaw moment of the car increases in accordance with the magnitude of the lateral acceleration. By use of the lateral acceleration corresponding gain which was set, the means (a) is controlled by a means (f) with the sum of the steering angle feed-forward term and the yawrate feedback term so.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front / rear wheel steering control device for giving an auxiliary steering angle to at least one of the front and rear wheels at the time of steering input or disturbance input.

[0002]

2. Description of the Related Art Conventionally, as this type of front and rear wheel steering control device, for example, one disclosed in Japanese Patent Laid-Open No. 60-193773 is known.

The above-mentioned conventional source discloses a technique for controlling the auxiliary steering angle given to the rear wheels by the addition value of the steering angle feedforward term and the yaw rate feedback term. In this conventional technique, the following equation is used. Rear wheel auxiliary rudder angle δ
Is required.

Δ = k1δf + k2ψ 'where (k1δf); steering angle feedforward term k1; first proportional constant (corresponding to vehicle speed) δf; steering wheel steering angle (k2ψ'); yaw rate feedback term k2; second proportional constant (fixed value or selected value depending on running conditions) ψ '; yaw rate

[0005]

However, in the above-mentioned conventional front and rear wheel steering control device, both the first proportional constant k1 which is the feedforward gain and the second proportional constant k2 which is the feedback gain are related to the lateral acceleration. On the other hand, since it is given by a constant value, for example, in the limit running area (high lateral acceleration area), the vehicle does not turn in the turning direction as intended by the driver, so that the turning performance is not improved. There is a problem of being sufficient.

That is, in the limit traveling area, the turning radius is usually large and the understeer is strong.

The present invention has been made by paying attention to the above problems, and in a front and rear wheel steering control device for giving an auxiliary steering angle to at least one of the front and rear wheels at the time of steering input or disturbance input, The problem is to improve the turning performance of the.

[0008]

In order to solve the above problems, in the front and rear wheel steering control device of the present invention, the auxiliary steering angle is controlled by the addition value of the steering angle feedforward term and the yaw rate feedback term, and The gain of at least one of the terms is changed to increase the yaw moment according to the magnitude of the lateral acceleration.

That is, as shown in the claim correspondence diagram of FIG. 1, an auxiliary steering means a for giving an auxiliary steering angle to at least one of the front and rear wheels by an external command regardless of steering input, and steering wheel steering. Steering wheel steering angle detecting means b for detecting an angle, yaw rate detecting means c for detecting yaw rate, lateral acceleration detecting means d for detecting lateral acceleration,
A lateral acceleration corresponding gain setting means e for changing at least one of the feedback gain and the feedforward gain in a direction of increasing the yaw moment of the vehicle in accordance with the magnitude of the lateral acceleration, and the set lateral acceleration corresponding gain are used. Assist for outputting to the auxiliary steering means a a command to give an auxiliary steering angle to at least one of the front and rear wheels by the sum of the steering angle feedforward term based on the steering angle of the steering wheel and the yaw rate feedback term based on the detected yaw rate. The steering angle control means f is provided.

[0010]

At the time of steering input or disturbance input, in the lateral acceleration corresponding gain setting means e, at least one of the feedback gain and the feedforward gain is changed to increase the yaw moment of the vehicle according to the magnitude of the lateral acceleration. The lateral acceleration corresponding gain is set as described above, and the auxiliary steering angle control unit f detects the steering angle feedforward term based on the steering angle using the lateral acceleration corresponding gain set by the lateral acceleration corresponding gain setting unit e. A command for giving an auxiliary steering angle to at least one of the front and rear wheels is output to the auxiliary steering means a by the addition value with the yaw rate feedback term based on the yaw rate.

Therefore, when turning acceleration is performed in the limit traveling region where high lateral acceleration is generated, an auxiliary steering angle is given to at least one of the front and rear wheels in a direction that promotes the generation of yaw rate of the vehicle. On the other hand, in the limit travel area, the load shifts from the front wheels to the rear wheels, and the understeer becomes stronger, so the understeer tendency can be weakened by this auxiliary steering angle control, and the limit turning performance can be improved.

[0012]

【Example】

 (First Embodiment) The configuration will be described.

FIG. 2 is an overall system diagram showing a front / rear wheel steering control device of the first embodiment of the present invention for giving an auxiliary steering angle only to the rear wheels.

The front wheels 1L, 1R of the vehicle to which the front-rear wheel steering control device of the first embodiment is applied are connected to the front wheels 1L, 1R via the left and right front wheel steering mechanisms 3L, 3R based on the steering input to the steering wheel 2. A steering unit 4 for steering is provided, and the left and right rear wheel steering mechanisms 9L, 9R are provided to the rear wheels 8L, 8R.
A rear wheel hydraulic cylinder 10 (corresponding to auxiliary steering means) that gives an auxiliary steering angle to the rear wheels 8L and 8R via R is provided.

The rear wheel side hydraulic cylinder 10 drives the rear wheel side hydraulic cylinder 10 by applying a control pressure from a hydraulic source unit (not shown) via the rear wheel side servo valve 15.

The rear-wheel-side servo valve 15 receives a command from the control unit 17, for example, right steering,
Three positions of holding and left steering are switched and controlled.

The control unit 17 includes a steering angle sensor 21 (corresponding to steering wheel steering angle detecting means), a yaw rate sensor 22 (corresponding to yaw rate detecting means), a vehicle speed sensor 20, and a lateral acceleration sensor 23 (corresponding to lateral acceleration detecting means). ) From the sensor signal is input.

The auxiliary rudder angle control law incorporated in the control unit 17 as a control program will be described.

In the first embodiment, the lateral acceleration corresponding gain k
_{Using 1} and k ₂ , the rear wheel auxiliary rudder is operated according to the control law expressed by the following formula, which is the sum of the steering angle feedforward term based on the steering angle δ _f and the yaw rate feedback term based on the detected yaw rate ψ ′. An angle δ _r is given (corresponding to auxiliary steering angle control means).

Δ _r = −k ₁ · C 1 · δ _f + k ₂ · C 2 · ψ ′ (1) where k ₁ ; lateral acceleration corresponding gain C 1 of feedforward term; first proportional constant k ₂ ; of feedback term Lateral acceleration corresponding gain C2; second proportional constant C1 and C2 are the prior documents of JP-A-60-193773.
It corresponds to k1 and k2 of the issue.

As shown in FIG. 3, the lateral acceleration-corresponding gain k ₁ is given as a value that gradually increases in a quadratic function from 1 in a region where the lateral acceleration YG is large. The gain k ₂ is the lateral acceleration as shown in FIG.
In a large YG region, the value is given as a value that gradually decreases from 1 as a quadratic function (corresponding to a lateral acceleration corresponding gain setting means).

The operation will be described.

In the limit traveling area where a high lateral acceleration YG is generated, the turning radius becomes large and the understeer becomes strong.

However, among the control rules based on the above equation (1),
The steering angle feedforward term by {-k ₁ · C 1 · δ _f } is the rear wheels 8L and 8R with respect to the steering direction of the front wheels 1L and 1R.
It has a meaning as an anti-phase term that gives an anti-auxiliary steering angle to.
Further, the yaw rate feedback term by {k ₂ · C 2 · ψ ′} is the rear wheels 8L, 8 with respect to the steering direction of the front wheels 1L, 1R.
It has a meaning as an in-phase term that gives an in-phase auxiliary steering angle to R.

Moreover, as shown in FIG. 3, the lateral acceleration corresponding gain k ₁ becomes larger as the lateral acceleration YG becomes higher, whereas the lateral acceleration corresponding gain k ₂ becomes larger.
Becomes higher, the smaller the value becomes, and in the high lateral acceleration region, the weighting of {-k ₁ · C 1 · δ _f }, which is an antiphase term, increases.

Therefore, the yaw rate ψ'in the limit travel area.
Auxiliary steering angles are given to the rear wheels 8L and 8R in the direction of promoting the occurrence of the above, the understeer tendency can be weakened, the turning performance of the vehicle can be increased, and the limit turning performance can be improved.

The effects will be described.

(1) The rear wheels 8 during steering input or disturbance input
In the front and rear wheel steering control device that gives an auxiliary steering angle to L and 8R, the steering angle feedforward term {-k ₁ · C ₁ is used by using the lateral acceleration corresponding gains k ₁ and k ₂ that increase the yaw moment of the vehicle in the high lateral acceleration region.・ Δ _f } and the yaw rate feedback term {k ₂・ C2 ・ ψ '} are added to control the rear wheel auxiliary steering angle δ _r , so that the turning performance in the limit traveling area can be improved. it can.

(Second Embodiment) The entire system configuration of the front and rear wheel steering control device of the second embodiment of the present invention is such that only the rear wheels are provided with an auxiliary steering angle and is the same as in FIG. To do.

The auxiliary rudder angle control law incorporated in the control unit 17 as a control program will be described.

In the second embodiment, the lateral acceleration corresponding gain k
_{Using 1} and k ₂ , the rear wheel auxiliary rudder is operated according to the control law expressed by the following formula, which is the sum of the steering angle feedforward term based on the steering angle δ _f and the yaw rate feedback term based on the detected yaw rate ψ ′. An angle δ _r is given (corresponding to auxiliary steering angle control means).

Δ _r = k ₁ · G · δ _f + k ₂ · r (ψ′−Ψ _T ′) (2) where k _{1 is} the lateral acceleration corresponding gain G of the feedforward term G is the feedforward transfer function k ₂ The lateral acceleration corresponding gain r of the feedback term; the feedback gain (r> 0) Ψ _T '; the target yaw rate characteristic The lateral acceleration corresponding gain k ₁ has a value in a large lateral acceleration YG region as shown in FIG. As shown in FIG. 4, the lateral acceleration-corresponding gain k ₂ is given as a quadratic function gradually decreasing from 1 as a quadratic function. It is given as a value that gradually increases (corresponding to a lateral acceleration corresponding gain setting means).

The operation will be described.

In the limit traveling area where a high lateral acceleration YG is generated, the turning radius becomes large and the understeer becomes strong.

However, among the control rules based on the above equation (2),
The steering angle feedforward term by {k ₁ · G · δ _f } increases the vehicle stability in the limit traveling region, that is, the front wheel 1
It has a meaning as an in-phase term that gives an in-phase auxiliary steering angle to the rear wheels 8L, 8R with respect to the steering direction of L, 1R. Also, {k ₂ ·
The yaw rate feedback term by r (ψ′−Ψ _T ′) makes the actual yaw rate ψ ′ match the target yaw rate characteristic Ψ _T ′ even in the limit traveling area, that is, when the understeer is strong, the steering direction of the front wheels 1L, 1R is Rear wheels 8L, 8
It has a meaning as an antiphase term which gives an antiphase auxiliary steering angle to R.

Moreover, as shown in FIG. 4, the lateral acceleration corresponding gain k ₂ becomes larger as the lateral acceleration YG becomes higher, whereas the lateral acceleration corresponding gain k ₁ becomes larger.
Becomes higher, the smaller the value becomes, and in the high lateral acceleration region, the weighting of the opposite phase term {k ₂ · r (ψ′−Ψ _T ′)} increases.

Therefore, the yaw rate ψ'in the limit travel area.
Auxiliary steering angles are given to the rear wheels 8L and 8R in the direction of promoting the occurrence of the above, the understeer tendency can be weakened, the turning performance of the vehicle can be increased, and the limit turning performance can be improved.

The effect will be described.

(2) Rear wheel 8 during steering input or disturbance input
In the front and rear wheel steering control device that gives an auxiliary steering angle to L and 8R, the steering angle feedforward term {k ₁ · G · is used by using the lateral acceleration corresponding gains k ₁ and k ₂ that increase the yaw moment of the vehicle in the high lateral acceleration region. Since it is a device that controls the rear wheel auxiliary steering angle δ _r by the added value of δ _f } and the yaw rate feedback term {k ₂ · r (ψ′−Ψ _T ′)}, the turning performance is improved in the limit travel area. Can be planned.

(Third Embodiment) The configuration will be described.

FIG. 5 is an overall system diagram showing a front / rear wheel steering control device according to a third embodiment of the present invention which gives an auxiliary steering angle to both the front and rear wheels.

The front wheels 1L, 1R of the vehicle to which the front / rear wheel steering control device of the third embodiment is applied are connected to the front wheels 1L, 1R via the left and right front wheel steering mechanisms 3L, 3R based on the steering input to the steering wheel 2. In addition to the steering unit 4 for steering,
A front wheel hydraulic cylinder 7 is provided which gives an auxiliary steering angle to the front wheels 1L, 1R by making a stroke of a rack tube of the steering unit 4 (supported to the vehicle body 5 via an elastic body 6), and rear wheels 8L, 8R are provided. Left and right rear wheel steering mechanism 9
A rear wheel hydraulic cylinder 10 is provided which gives an auxiliary steering angle to the rear wheels 8L and 8R via L and 9R.

The front wheel side hydraulic cylinder 7 and the rear wheel side hydraulic cylinder 10 have a common hydraulic power source unit 11 and are controlled from this hydraulic power source unit 11 via a front wheel side fail-safe valve 12 and a front wheel side servo valve 13. The front wheel hydraulic cylinder 7 is driven by applying pressure, and the rear wheel hydraulic cylinder 10 is driven by applying control pressure from the hydraulic power source unit 11 via the rear wheel fail-safe valve 14 and the rear wheel servo valve 15. I am trying to let you. still,
The hydraulic power source unit 11 includes a hydraulic pump 11a driven by an engine 16, an unload valve 11b, a pressure switch 11c, an accumulator 11d, and a reservoir 1.
1e is provided so that a constant pressure hydraulic oil is supplied.

The front wheel side fail-safe valve 12 and the rear wheel side fail-safe valve 14 are switched between two ON / OFF positions by a command from the control unit 17.
The front wheel side servo valve 13 and the rear wheel side servo valve 1
5 is from the control unit 17 to the servo amplifier 1
A command via 8 and 19 switches and controls three positions of right steering, holding, and left steering.

The control unit 17 includes a vehicle speed sensor 20, a steering angle sensor 21 (corresponding to steering wheel steering angle detecting means), a yaw rate sensor 22 (corresponding to yaw rate detecting means), and a lateral acceleration sensor 23 (corresponding to lateral acceleration detecting means). ), Front wheel side displacement sensor 24, rear wheel side displacement sensor 2
5, neutral switch 26, clutch switch 2
7. The detection signal from the stop lamp switch 28 is input. The sensor signal from the yaw rate sensor 22 is amplified and input via the amplifier 29.

The auxiliary rudder angle control law incorporated in the control unit 17 as a control program will be described.

In the third embodiment, the lateral acceleration corresponding gain k
_{Using 1} , k ₂ , k ₃ , and k ₄ , the control represented by the following formula, which is the sum of the steering angle feedforward term based on the steering angle δ _f and the yaw rate feedback term based on the detected yaw rate ψ ′. The front wheel auxiliary rudder angle δ _f0 and the rear wheel auxiliary rudder angle δ _r are given according to the rule (corresponding to auxiliary rudder angle control means).

Δ _f0 = k ₁ · G _f · δ _f −k ₂ · R _f · (ψ′−Ψ _T ′) δ _r = k ₃ · G _r · δ _f + k ₄ · R _r · (ψ′− Ψ _T ') (3) where k ₁ and k _{3 are the} feed-forward term lateral acceleration corresponding gains G _f and G _r ; the feed-forward transfer functions k ₂ and k _{4 are the} feedback term lateral acceleration corresponding gains R _f , R _r ; Feedback gain (R _f > 0, R _r >
0) Ψ _T '; target yaw rate characteristic As shown in FIG. 6, the lateral acceleration-corresponding gains k ₁ and k ₄ are values that gradually increase as a quadratic function from 1 in a region where the lateral acceleration YG is large ( k ₁ > k ₄ ), and the lateral acceleration corresponding gains k ₂ and k ₃ gradually decrease from 1 as a quadratic function in a region where the lateral acceleration YG is large, as shown in FIG. Value (k ₂ <k ₃ ) (corresponding to the lateral acceleration corresponding gain setting means).

The operation will be described.

(A) At the time of limit running In the limit running region where a high lateral acceleration YG is generated, the turning radius becomes large and the understeer becomes strong.

However, in the front wheel side of the control law based on the equation (3), the lateral acceleration corresponding gain of k ₁ > k ₂ is set in the high lateral acceleration region, so that {k ₁ · G _f · δ _f The front wheel increase term by {} is more weighted than the front wheel cutback term by {-k ₂ · R _f · (ψ′−Ψ _T ′)}.

On the rear wheel side in the control law based on the equation (3), the lateral acceleration corresponding gain of k ₄ > k ₃ is set in the high lateral acceleration region, so that {k ₄ · R _r · ( ψ'-Ψ _T ')} weighting increases from phase term reverse phase term by _{{k 3 · G r · δ} f} by.

Therefore, the yaw rate ψ'in the limit travel area.
Front wheels 1L, 1R and rear wheels 8 in the direction of promoting the generation of
Auxiliary steering angles are given to L and 8R, the understeer tendency is weakened, the turning performance of the vehicle can be increased, and the limit turning performance can be improved.

(B) When steering the steering wheel When the steering input is applied to the steering wheel 2, and the actual yaw rate ψ ′ always matches the target yaw rate characteristic Ψ _T ′,
ψ '= Ψ _T ', and the front wheel auxiliary steering angle δ _{f0 according} to the above equation (3).
And the rear wheel auxiliary steering angle δ _r is δ _f0 = k ₁ · G _f · δ _f δ _r = k ₃ · G _r · δ _f .

That is, the feedback component is eliminated, and the feedforward control becomes the main component, and the vehicle moves according to the driver's intention.

Here, the relationship between G _f , G _r and Ψ _T 'is shown in Japanese Patent Laid-Open No. 1-215672. That is,
In a linear two-degree-of-freedom motion equation using a simple two-wheel model, the result obtained by performing feedforward control of the front and rear wheels to obtain the target characteristic Ψ _T 'is the transfer functions G _f and G _r . is there.

In other words, from the target characteristic, the transfer function G _f ,
Equation (1) can be applied to the case where G _r is analytically obtained.

(C) At the time of disturbance input When the yaw rate occurs due to the disturbance applied to the vehicle without steering the steering wheel 2, the steering wheel steering angle δ
_{If f} is δ _f = 0 and ψ ′ <0, the front wheel auxiliary rudder angle δ _f0 and the rear wheel auxiliary rudder angle δ _r are _expressed by the above equation (3) as δ _f0 = −k ₂ · R _f · ψ ′ > 0 δ _r = k ₄ · R _r · ψ ′ <0.

Therefore, with respect to the yaw rate ψ '<0 (counterclockwise) applied to the vehicle, the front wheels 1L and 1R are given the right front wheel auxiliary steering angle δ _f0 , and the rear wheels 8L and 8R are the left direction. As the rear wheel auxiliary steering angle δ _r is given, the front and rear wheels are automatically corrected and steered in the direction that suppresses the yaw rate ψ ', and the course of the vehicle is less disturbed by disturbances such as uneven roads and crosswinds. ..

[0060] (d) vehicle yaw rate characteristics in the vehicle yaw characteristics during turning, etc., (3) As shown in equation incorporating deviation terms of the actual yaw rate [psi 'and target yaw rate characteristics [psi _T' in the control law, Since the so-called feedback control is performed, the target yaw rate characteristic can be achieved with high accuracy, and even if the vehicle characteristic deteriorates over time due to tire wear, etc., the system is designed to approach the model of the target yaw rate characteristic Ψ _T '. It is adaptable.

The effect will be described.

(3) Front wheel 1 at the time of steering input or disturbance input
In the front and rear wheel steering control device that gives auxiliary steering angles to L, 1R and rear wheels 8L, 8R, lateral acceleration corresponding gains k ₁ , k ₂ , k ₃ , which increase the yaw moment of the vehicle in a high lateral acceleration region,
Using k ₄ , the steering angle feedforward term {k ₁ · G _f · δ
_f } and the yaw rate feedback term {−k ₂ · R _f · (ψ ′
-Ψ _T ')} and the front wheel auxiliary steering angle δ _f0 are controlled, and the steering angle feedforward term {k ₃ · G _r · δ _f } and the yaw rate feedback term {k ₄ · R _r · (ψ ′). − Ψ _T ')}
Since the device for controlling the rear wheel auxiliary rudder angle δ _r is used by the addition value of and, it is possible to improve the turning performance in the limit traveling region.

(4) Since the device for giving the auxiliary steering angles δ _f0 and δ _r to the front and rear wheels at the control speed expressed by the above formula (3) is used, the disturbance resistance is improved and the adaptability to the deterioration of the vehicle performance over time. , It is also possible to achieve the target characteristics with high accuracy.

(5) Linear 2 using a simple two-wheel model
In the equation of motion with degrees of freedom, the result obtained by solving the target yaw rate characteristic Ψ _T 'by feedforward control of the front and rear wheels is the transfer function G _f , G _r , so the control circuit is simple, Cost performance can be improved.

When the analysis model is complicated and the target characteristic Ψ _T 'is a high-order component, the transfer functions G _f and G _{r are} naturally.
Can be derived analytically in the same way, but has a higher order. In this case, the control accuracy is improved in one aspect, but the control circuit is complicated and the cost performance is reduced. In that respect, the control law of the embodiment of the present invention is practical.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, the lateral acceleration sensor is used as the lateral acceleration detecting means. However, as shown in FIG. 7, the steering wheel steering angle δ _f is used without using the lateral acceleration sensor.
And it detects a vehicle speed V, the by equation _{YG = n · δ f · V} 2 ( constant determined by the vehicle specification) may be obtained by calculation. In this case, the cost is reduced and the system is simplified, so that the reliability is improved.

In the embodiment, the gain of both the steering angle feedforward term and the yaw rate feedback term is set as the lateral acceleration corresponding gain, but the gain of only one of the terms is set as the lateral acceleration corresponding gain. It may be an example.

[0069]

As described above, according to the present invention, a steering angle feedforward term and a yaw rate are provided in a front and rear wheel steering control device that gives an auxiliary steering angle to at least one of the front and rear wheels at the time of steering input or disturbance input. The auxiliary steering angle is controlled by the sum of the feedback term and the gain of at least one of the terms is changed to increase the yaw moment according to the magnitude of the lateral acceleration. It is possible to obtain an effect that it is possible to improve the turning performance in the vehicle.

[Brief description of drawings]

FIG. 1 is a complaint response showing a front and rear wheel steering control device of the present invention.

FIG. 2 is an overall system diagram showing a front / rear wheel steering control device of a first embodiment.

FIG. 3 is a gain characteristic diagram corresponding to lateral acceleration in the first embodiment device.

FIG. 4 is a lateral acceleration corresponding gain characteristic diagram in the device of the second embodiment.

FIG. 5 is an overall system diagram showing a front / rear wheel steering control device of a third embodiment.

FIG. 6 is a gain characteristic diagram corresponding to lateral acceleration in the device of the third embodiment.

FIG. 7 is an overall system diagram showing another embodiment of the front and rear wheel steering control device.

[Explanation of symbols]

 a auxiliary steering means b steering wheel steering angle detection means c yaw rate detection means d lateral acceleration detection means e lateral acceleration corresponding gain setting means f auxiliary steering angle control means

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B62D 113: 00 137: 00

Claims (1)

[Claims] 1. A steering wheel steering angle detecting means for detecting a steering wheel steering angle, an auxiliary steering means for applying an auxiliary steering angle to at least one of the front and rear wheels by an external command regardless of steering wheel steering input, and a yaw rate. The yaw rate detecting means for detecting the lateral acceleration, the lateral acceleration detecting means for detecting the lateral acceleration, and the gain of at least one of the feedback gain and the feedforward gain are changed in the direction of increasing the yaw moment of the vehicle according to the magnitude of the lateral acceleration. At least one of the front and rear wheels is obtained by adding the lateral acceleration corresponding gain setting means and the set lateral acceleration corresponding gain to the sum of the steering angle feedforward term based on the steering angle of the steering wheel and the yaw rate feedback term based on the detected yaw rate. Auxiliary steering angle for outputting a command to give an auxiliary steering angle to the auxiliary steering means Front and rear wheel steering control apparatus characterized by comprising a control means, a.