JPH0327423B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a steering angle control device for a vehicle that can freely control the motion performance of a vehicle during steering, and in particular, it relates to a steering angle control device for a vehicle that can freely control the motion performance of a vehicle during steering. The present invention relates to a steering angle control device for a vehicle that makes it possible to appropriately change the object of emphasis in motion performance.

(Prior art) Vehicles equipped with conventional mechanical link steering devices are configured to steer the front wheels in response to the amount of steering from the steering wheel, and the dynamic performance associated with steering depends on the vehicle's vehicle performance. The driving performance is determined uniformly based on specifications, and is unique to each vehicle type.

On the other hand, the applicant of this application previously filed a patent application filed in
No. 147018, Patent Application No. 188153, Patent Application No. 1881-
In No. 188158, etc., a target vehicle with target dynamic performance is assumed, and based on the vehicle specifications and equation of motion regarding the target vehicle, the target value of the motion variable corresponding to the steering wheel steering amount and vehicle speed, that is, the target vehicle The steering angle of the vehicle's wheels (at least one of the front wheels or rear wheels) is determined so that the vehicle (vehicle equipped with the device) achieves the motion variable target value representing the motion performance exhibited by the vehicle. We are proposing a device to control this.

In other words, if you use this device, for example, even if your vehicle is a sedan type vehicle, if you set the target vehicle to be a sports car type vehicle, you can achieve the driving performance of a sports car even though the body structure etc. is of the sedan type. It is possible to freely control exercise performance, such as by making the body possess the following characteristics.

(Problems to be Solved by the Invention) By the way, the inventor of the present application has the following problems regarding the above device:
Through further research, we discovered the following improvements.

In other words, in the device according to the above-mentioned prior application, if only one of the front wheels or the rear wheels is subject to steering angle control, only one motion variable target value can be handled. If the wheel steering angle is controlled by determining only the target value of
Steering may be performed with more emphasis on lateral acceleration characteristics than on yaw rate, and in this case, it is not possible to obtain appropriate lateral acceleration characteristics.

(Means for solving the problems) In order to solve the above problems, the present invention provides the first
It is equipped with the means shown in the figure.

The motion variable target value calculating means 102 calculates the steering angle θ _S of the steering wheel detected by the steering wheel steering angle detecting means 100 and the vehicle speed by calculating one or more target vehicle models having a desired motion performance set in advance. Multiple types of motion variable target values M ₁ corresponding to the vehicle speed V detected by the detection means 101
Find ~M _o (n is a natural number).

Steering angle optimum value calculation means 103(1) to 103(n)
are provided in the same number for each of the plurality of motion variable target values M ₁ to M _o , and each of the motion variable target values
Optimum values δ ₁ to _{δ o} of the wheel steering angle of at least one of the front wheels or the rear wheels are determined from a given one of M ₁ to _{M o} and the vehicle specifications of the own vehicle.

The steering angle target value calculation means 104 performs a weighted average on the wheel steering angle optimum values δ ₁ to δ _o obtained by the steering angle optimum value calculation means 103(1) to 103(n), Determine the target angle value.

Then, the wheel steering means 105 steers the corresponding wheel of the front wheels or the rear wheels to the wheel steering angle target value.

(Function) The plurality of motion variable target values M ₁ to _Mo obtained by the motion variable target value calculation means 102 are calculated by the steering angle optimum value calculation means 103(1) to 103 provided for each of them.
(n), the wheel steering angles are converted into optimum wheel steering angle values δ ₁ to δ _o corresponding to the respective motion variable target values M ₁ to M _o .

These wheel steering angle optimum values δ ₁ to _{δ o} are subjected to a weighted average by the steering angle target value calculation means 104,
A wheel steering angle target value is determined.

Then, the wheel steering means 105 performs steering so that the actual wheel steering angle becomes the wheel steering angle target value.

Therefore, for example, by performing the above-mentioned weighted averaging in accordance with the running condition and steering condition of the vehicle, it is possible to adjust which of the plurality of motion variable target values M ₁ to _{M o} is to be emphasized, and to achieve a more advanced This means that the motor performance can be controlled even more freely.

(Example) FIG. 2 shows the configuration of a first embodiment of the present invention.

The microcomputer 1 inputs the vehicle speed V detected by the vehicle speed sensor 3 and the steering amount θ _S of the steering wheel 8 detected by the steering wheel steering amount sensor 2, and calculates the motion variable target value and the front wheel steering angle target value. Perform the calculation of _F.

The front wheel steering device 4 is a device that performs steering control of the front wheels 9 and 10 based on data of a front wheel steering angle target value _F given from the microcomputer 1.

It is the hydraulic steering device 6 that actually steers the front wheels 9 and 10. The front wheel steering device 4 and the hydraulic steering device 6 are configured as shown in FIG. 3, for example.

The hydraulic steering device 6 includes two pistons 32 and 33, with tie rods at both ends (not shown).
The shaft 31 connected to the left and right hydraulic chambers 3
The wheels are steered by moving them in the axial direction by setting a difference between the working oil pressures of the wheels 4 and 35.

Further, within the center chamber 37, repulsion plates 38 and 39, which are biased in left and right opposite directions by a spring 36, are loosely fitted onto the shaft 31. This is for returning the shaft 31 to its original neutral position when it is pulled out.

The front wheel steering device 4 includes a slenoid driver 21
, control valve 22, and oil pump 2
6 and an oil tank 27.

The control valve 22 includes oil passages 28 and 29 that communicate with the left and right hydraulic chambers 34 and 35 of the hydraulic steering device 7, and includes a spool valve 25 that adjusts the amount of hydraulic oil flowing into these oil passages 28 and 29. ing. This spool valve 25 has its left and right ends loosely fitted into the electromagnetic solenoids 23 and 24.
Depending on the magnitude of the magnetic force of the electromagnetic solenoids 23 and 24, the solenoid moves in the axial direction and adjusts the amount of hydraulic oil applied to the left and right hydraulic chambers 34 and 35.

The solenoid driver 21 sends a current signal proportional to the front wheel steering angle target value _F given from the microcomputer 1 to either the left or right electromagnetic solenoid 23,
24. In this case, control is performed by switching the electromagnetic solenoid that applies current between the left and right sides depending on the steering direction of the wheels.

Furthermore, in this embodiment, the rear wheels 11 and 12 are not steered, and only the front wheels 9 and 10 are controlled in terms of steering angle.

FIG. 4 is a flow chart of the processing executed by the microcomputer 1. The operation of this embodiment will be explained below along with the explanation of this flowchart.

The process shown in Fig. 4 is repeatedly executed every predetermined time Δt, and when the ignition switch is
Initialization is performed when it is turned on and power is supplied.

In the process of step 41, the steering angle sensor 2 and the vehicle speed sensor 3 are connected to the microcomputer 1.
Read both the steering wheel angle θ _S and vehicle speed V data input to the .

Next, in the process of step 42, the vehicle specifications of the first target vehicle models (hereinafter abbreviated as "first target vehicles") stored in advance in the memory are read out from the memory, and the vehicle specifications of the first target vehicle models are read out from the memory. The equation of motion for the first target vehicle is solved from the specifications, the steering angle θ _S and the vehicle speed V, and the target value of the yawing movement (in this example, the target value of the yaw rate) and the yaw angle corresponding to θ _S and V are calculated. Calculations are performed to determine the target acceleration value.

The above-mentioned first target vehicle is assumed to be a vehicle having the target characteristics regarding yawing movement (this may be an actual vehicle or a virtual empty vehicle), and the first target vehicle is The vehicle specifications are the vehicle specifications of this assumed vehicle.

In this embodiment, the following vehicle specifications are used as the first target vehicle specifications.

I _Z1 : Yaw inertia of the first target vehicle M ₁ : Body mass of the first target vehicle L _F1 : Distance between the front axle and center of gravity of the first target vehicle L _R1 : Distance between the rear axle and center of gravity of the first target vehicle N ₁ : Steering gear ratio of the first target vehicle K _F1 : Cornering power of the front wheels of the first target vehicle K _R1 : Cornering power of the rear wheels of the first target vehicle The calculation is performed according to the following formula.

M ₁ (V〓 _y1 +〓 ₁ V) = 2C _F1 +2C _R1 ……(1) I _Z1 ¨ ₁ = 2L _F1 C _F1 −2L _R1 C _R1 ……(2) C _F1 =K _F1 {θ _S /N ₁ − (V _y1 +L _F1 〓 ₁ )/V} ……(3) C _R1 = −K _R1 (V _y1 −L _R1 〓 ₁ )/V ……(4) ¨=¨ ₁ ……(5) 〓 =〓 ₁ ...(6) Here, 〓 ₁ : Yaw rate of the first target vehicle ₁ : Yaw angular acceleration V of the first target vehicle _y1 : Speed in the y-axis direction of the first target vehicle V〓 _y1 : First target Side slip acceleration in the y-axis direction of the vehicle C _F1 : Front wheel cornering force of the first target vehicle C _R1 : Rear wheel cornering force of the first target vehicle.

Equations (1) and (2) above are equations of motion for the first target vehicle, and in order to solve these equations, 2
This integral operation can be performed using the rectangular integral method expressed as A(t+Δt)=A(t)+Δt・A(t), or other methods such as the Rungekutta method, etc. Use an appropriate integration method depending on the situation.

During the above calculation, an equation of motion regarding lateral motion is also calculated, but since this first target vehicle is a target vehicle regarding yawing motion, the variables of lateral motion (V _y1 ,
V〓 _y1 ) is not used in the calculation of the steering angle target value _F , which will be described later.

Next, in the process of step 43, the vehicle having the target characteristics regarding lateral motion is
By assuming a target vehicle model (hereinafter abbreviated as "second target vehicle"), second target vehicle specifications stored in memory in advance are read out, and these second target vehicle The equation of motion for the second target vehicle is solved from the specifications, the steering angle θ _S and the vehicle speed V, and the target value of the lateral motion corresponding to θ _S and V (in this example, the target value of the lateral acceleration) is determined. A computation is performed to obtain .

In this embodiment, the second target vehicle specifications are as follows:
The following vehicle specifications are used.

I _Z2 : Yaw inertia of the second target vehicle M ₂ : Body mass of the second target vehicle L _F2 : Distance between the front axle and center of gravity of the second target vehicle L _R2 : Distance between the rear axle and center of gravity of the second target vehicle N ₂ : Steering gear ratio of the second target vehicle K _F2 : Cornering power of the front wheels of the second target vehicle K _R2 : Cornering power of the rear wheels of the second target vehicle The above lateral acceleration target value can be calculated using the following formula. shall be carried out in accordance with.

M ₂ (V〓 _y2 +〓 ₂ V) = 2C _F2 +2C _R2 ……(7) I _Z2 ¨ ₂ = 2L _F2 C _F2 −2L _R2 C _R2 ……(8) C _F2 =K _F2 {θ _S /N ₂ −(V _y2 +L _F2 〓 ₂ )/V} …(9) C _R2 =−K _R2 (V _y2 −L _R2 〓 ₂ )/V……(10) =V〓 _y2 +〓 ₂ V…… (11) Here, 〓 ₂ : Yaw rate of the second target vehicle 〓 ₂ : Yaw angular acceleration V of the second target vehicle _y2 : Velocity in the y-axis direction of the second target vehicle V〓 _y2 : Y-axis direction of the second target vehicle Side slip acceleration C _F2 : Front wheel cornering force of the second target vehicle C _R2 : Rear wheel cornering force of the second target vehicle.

Equations (7) and (8) above are the equations of motion for the second target vehicle, and the equations of motion for the second target vehicle are
Integral calculations similar to (1) and (2) are performed.

During the above calculation, the equation of motion regarding the yawing motion is also resolved, but since this second target vehicle is the eye vehicle regarding the lateral motion,
Variables of yawing motion determined by calculation (〓 ₂ ,
_¨2 ) is not used in the calculation of the steering angle target value _F , which will be described later.

In this way, the present embodiment calculates the yaw rate target value, the yaw angular velocity target value, and the lateral acceleration from the first target vehicle and the second target vehicle, which have mutually independent motion performance, thereby controlling the yawing motion. The target value (〓, ¨) and the target value () for the lateral movement are independent and have no correlation with each other, so that the target movement performance can be divided into two types: yawing movement and lateral movement. You can set it freely in both cases.

Then, in the next steps 44 and 45, the front wheel steering angle (this is referred to as the "optimum steering angle value δ") necessary to achieve the yawing movement target value (〓, ¨) for the own vehicle, or The front wheel steering angle (this is referred to as the "optimum steering angle value δ") necessary for the own vehicle to achieve the lateral motion target value ( ) is calculated using the vehicle specifications of the own vehicle.

It is assumed that the above-mentioned own vehicle is a vehicle in which the present embodiment device is mounted, and that the following vehicle specifications are stored in advance in the memory.

I _Z3 : Yaw inertia of own vehicle M ₃ : Body mass of own vehicle L _F3 : Distance between own vehicle's front axle and center of gravity L _R3 : Distance between own vehicle's rear axle and center of gravity K _F3 : Distance between own vehicle's front axle and center of gravity Cornering force K _R3 : Cornering force of the rear wheels of the own vehicle Then, in the process of step 44, the optimum steering angle value δ is determined from the yawing movement target values (〓, ¨) by the following calculation.

M ₃ (V _y 〓+〓V)=2C _F 〓+2C _R 〓 ……(12) C _R 〓=K _R3 (V _y 〓−L _R3 〓)/V ……(13) C _F 〓=L _R3 C _R 〓+1/2¨I _Z3 )/L _F3 ……(14) δ _F 〓=C _F 〓/K _F3 +(V _y 〓+L _F3 〓)/V ……(15) δ＝δ _F 〓 ...(16) Here, the state quantities (motion variables) that appear during the above calculation are the state quantities of the own vehicle determined by the calculation, and these are as follows.

V _y 〓: Speed of the own vehicle in the y-axis direction V _y 〓: Side slip acceleration of the own vehicle in the y-axis direction C _F 〓: Front wheel cornering power of the own vehicle C _R 〓: Rear wheel cornering power of the own vehicle Also, δ _F 〓 , is the front wheel steering angle of the own vehicle determined by the above calculation.

In the process of step 45, another steering angle optimum value δ is determined from the lateral motion target value () by the following calculation using the above vehicle specifications.

I _Z3 ¨=2L _F3 C _F 〓−2L _R3 C _R 〓 ……(17) V〓 _y 〓=−〓〓V ……(18) C _R 〓=−K _R3 (V _y 〓−L _R3 〓) /V ……(19) C _F 〓=1/2M ₃ −C _R 〓 ……(20) δ _F 〓=C _F 〓/K _F3 +(V _y 〓+L _F3 〓)/V ……(21) δ〓= _δF〓 ...(22) Here, the state quantity (motion variable) that appears during the above calculation is the state quantity of the own vehicle found by the calculation, and is the state quantity found by the calculation in step 44. The value is different from . These are as follows.

〓〓: Own vehicle's yaw rate 〓〓: Own vehicle's yaw angular acceleration V _Y 〓: Own vehicle's y-axis direction speed V _y 〓: Own vehicle's y-axis direction side slip acceleration C _F 〓: Own vehicle's front wheel cornering power C _R 〓: Rear wheel cornering power of the own vehicle, and δ _F 〓 is the front wheel steering angle of the own vehicle determined by the above calculation.

The two optimum steering angle values δ and δ〓 obtained in this way are the optimum steering angle value δ for realizing the yawing motion target value (〓, ¨) and the lateral motion target value () for realizing the yaw motion target value (〓, ¨). In this embodiment, in the next step 46, a weighted average is applied according to the vehicle speed V, and the ratio of emphasis on yawing motion and lateral motion is determined depending on the traveling speed. I'll try to adjust it.

For example, when driving at low speeds, the sideslip angle of the tires is small, so it is effective to perform dynamic performance control that emphasizes yawing motion, and as the vehicle speed increases, it is effective to change dynamic performance control that emphasizes lateral motion. The optimal control is to do so.

Therefore, in the process of step 46, the functions f ₁ (V) and f ₂ (V) of the vehicle speed V are expressed as f ₁ (V)=A/A+V ² (23) f ₂ (V)=V ² / A + V ² ... (24) (where A is an arbitrary constant) is determined by the calculation, and the front wheel steering angle target is determined using the weighted average of _F = f ₁ (V) δ + f ₂ (V) δ〓 ... (25) Determine the value _F.

As can be seen from equation (25), when the vehicle speed is V0,
δ _F δ approaches the optimum steering angle value for realizing the yawing movement target value, and conversely, the vehicle speed V≫0
When , _F δ〓 approaches the optimum value of the steering angle for realizing the target value of lateral motion.

The front wheel steering angle target value _F obtained by the weighted average in this manner is output to the front wheel steering device 4 through the process of step 47.

The front wheel steering device 4 adjusts the actual steering angles of the front wheels 9 and 10 to match the given front wheel steering angle target value δ _F.
Necessary hydraulic pressure is supplied to the hydraulic steering device 6, thereby steering the front wheels 9, 10.

Through the above operations, the vehicle equipped with the device of this embodiment adjusts the ratio of emphasis between yawing motion and lateral motion as the vehicle speed increases, and performs appropriate steering angle control.

FIG. 5 is a diagram showing the change characteristics of the yaw rate and lateral acceleration of a vehicle (own vehicle) equipped with the device of this embodiment.

As shown in Figure 5a, when the steering wheel is turned sharply, as shown by the broken lines in Figure 5b and c, in the case of a conventional vehicle that does not perform steering angle control, both the yaw rate and lateral acceleration decrease. , vibrates and is not stable.

On the other hand, in the case of a vehicle equipped with the device of this embodiment,
The characteristics shown by the solid lines in b and c of the same figure are f ₁ (V) = 1 and f ₂
When (V)=0, the characteristic shown by the dashed line is f ₁ (V)=
0 and f ₂ (V) = 1, and as the vehicle speed V changes, it changes within a region narrowed by both characteristic curves (hatched region in the figure).

When f ₁ (V)=1 and f ₂ (V)=0, emphasis is placed on the yawing motion, the yaw rate hardly oscillates, and its responsiveness is high. At this time, the lateral acceleration is
The response will be slower, but it will not fluctuate like a conventional car.

When f ₁ (V) = 0 and f ₂ (V) = 1, emphasis is placed on lateral motion and the response of lateral acceleration is improved. At this time, the yaw rate vibrates slightly, but it does not cause large vibrations like in conventional cars.

Next, FIG. 6 is a flowchart showing another example of control executed by the microcomputer 1 in FIG. 2 (this will be referred to as the "second embodiment"). In addition, in the same figure, the first
Steps that perform the same processing as those in the control content of the embodiment are given the same reference numerals.

In this embodiment, the yaw motion target value (〓, ¨) and the lateral motion target value () were obtained separately from two target vehicles in the first embodiment, whereas 〓 Find , ¨, (step
51) However, there is a difference.

The calculation content is the calculation in the first embodiment above.
Perform calculations similar to equations (1) to (6) to determine the yaw rate target value and yaw angular acceleration target value, and then perform calculations to determine the sideslip angle β at the center of gravity.
The target value of the lateral acceleration is determined from the sideslip angle β of the center of gravity, the yaw rate, and the vehicle speed V.

〓, ¨, obtained in this way is the first
As in the case of the embodiment, the two optimum steering angle values δ, δ〓 are calculated, and the optimum steering angle values δ, δ〓 are further added to the vehicle speed V.
The front wheel steering angle target value δ _F is determined by weighted averaging.

The effects of this embodiment are substantially the same as those of the first embodiment, but since there is only one target vehicle, 〓, ¨, have a correlation, and therefore, The target vehicle needs to be set to have the desired maneuverability in both yawing motion and lateral motion.

Next, FIG. 7 is a flowchart showing still another example of control executed by the microcomputer 1 in FIG. 2 (this will be referred to as the "third embodiment"). In this figure as well, steps that perform the same processing as the control shown in FIG. 4 are given the same reference numerals.

In this embodiment, like the second embodiment, only a single target vehicle is set, and the calculations regarding this single target vehicle (this is the same as the equations (1) to (6) above). ), the yaw movement target value 〓, ¨
(Step 52).

The difference from the second embodiment is that the lateral acceleration target value is obtained as the product of the yaw rate target value obtained in step 52 and the vehicle speed V (step 52).
53) That is. In other words, it is obtained as =〓V...(26).

This equation (26) does not include the sideslip angle β at the center of gravity. In other words, a lateral acceleration target value that makes the sideslip angle β at the center of gravity zero is determined.

Therefore, the vehicle equipped with the device of this embodiment has the first and second
Similar to the vehicle equipped with the example, in addition to the effect that the ratio of emphasis on yawing motion and lateral motion is adjusted according to the vehicle speed, control is performed so that the sideslip angle β at the center of gravity is always zero, making it extremely It exhibits good dynamic characteristics (the vehicle body always points in the direction of motion).

Next, FIG. 8 is a flowchart showing still another example of the control executed by the microcomputer 1 in FIG. 2 (this will be referred to as the "fourth embodiment"). Steps that perform the same processing as the control processing in the first embodiment shown in FIG. 4 are given the same reference numerals.

In the first embodiment, the front wheel steering angle target value _F was obtained by performing a weighted average with respect to vehicle speed on the two optimum steering angle values δ and δ〓, whereas in this embodiment, the process in step 54 Then, the steering wheel steering angular velocity θ〓 _S is determined, and the weighted average of the steering wheel steering angular velocity θ〓 _S is applied to δ, δ〓 to determine the front wheel steering angle target value δ _F (step 55).

This is advantageous when the vehicle body needs to move laterally rapidly, such as during an emergency avoidance situation, where control emphasizes lateral motion rather than yawing motion; conversely, during normal steering, This takes into consideration the fact that a better turning ability results in better driving performance for the driver, so it is better to perform control that emphasizes yawing movement.

In the process of step 55, the steering wheel steering angular velocity θ〓 _S
The two functions g ₁ (θ〓 _S ) and g ₂ (θ〓 _S ) for Using g ₁ (θ〓 _S ) and g ₂ (θ〓 _S ), we perform a weighted average as follows: _F = g ₁ (θ〓 _S ) δ〓 + g ₂ (θ〓 _S ) δ ... (27) Determine the steering angle target value _F.

As shown in Figure 9a, g ₁ (θ〓 _S ) becomes "1" when θ〓 _S is large, and becomes "0" when θ〓 _S is small.
, and g ₂ (θ〓 _S ) is the opposite characteristic.

Therefore, when the steering wheel steering angular speed θ〓 _S is large, the proportion of emphasis on lateral movement increases and effective performance is achieved in emergency avoidance situations, etc., whereas when the steering wheel steering angular speed θ〓 _S is small, on the other hand, the emphasis on lateral movement increases. , the proportion of emphasis on yawing motion increases, and the effect of improving turning performance during normal steering can be obtained.

Note that, as in this embodiment, weighted averaging processing using the steering wheel steering angular velocity θ〓 _S (steps 54 and 55)
is the weighted average processing according to the vehicle speed V in the second and third embodiments (steps in FIGS. 6 and 7).
46) can also be substituted.

It is also possible to perform a weighted average of both the vehicle speed V and the steering wheel steering angular velocity _θ〓S to perform appropriate control in response to both changes in the vehicle speed V and changes in the steering wheel steering angular speed _θ〓S .

Further, in each of the above embodiments, an example was shown in which the steering angle of the front wheels is controlled, but the present invention can also obtain the same operation and effect as the above embodiments by controlling the steering angle of the rear wheels. Moreover, it is also possible to adopt a configuration in which the steering angles of both the front wheels and the rear wheels are controlled.

Furthermore, in each of the above embodiments, examples were shown in which the motion variable target values were two types, the yawing motion target value and the lateral motion target value. A configuration in which a target value of force, etc. is added may also be used.

(Effects of the Invention) As explained in detail above, the present invention calculates a plurality of motion variable target values, calculates the optimum wheel steering angle value corresponding to each of these, and further By determining the wheel steering angle target value by applying a weighted average to the optimum wheel steering angle values, it is possible to adjust which of the plurality of motion variable target values is to be emphasized.

This makes it possible to control dynamic performance even more freely. For example, when driving at high speed and making a sharp turn, control is performed that emphasizes lateral acceleration rather than yaw rate, allowing the vehicle to move laterally. This makes it possible to perform advanced control such as improving performance and controlling the yaw rate when driving at low speeds or with less steering to improve the turning performance of the vehicle body.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of a first embodiment of the present invention, FIG. 3 is a block diagram of the front wheel steering device and hydraulic steering device in FIG. 2, and FIG. are flowcharts showing the control executed by the microcomputer in FIG. 2, and FIGS. 5 a to c.
is a dynamic characteristic diagram of a vehicle equipped with the device of the first embodiment of the present invention,
Figures 6 to 8 are flowcharts showing other examples of control executed by the microcomputer shown in Figure 2, and Figures 9a and b are data tables used in the control shown in Figure 8. FIG. 100...Steering wheel steering angle detection means, 101...
... Vehicle speed detection means, 102 ... Motion variable target value calculation means, 103 (1) to 103 (n) ... Steering angle optimum value calculation means, 104 ... Steering angle target value calculation means, 105
... Wheel steering means, 1 ... Microcomputer, 2 ... Steering wheel steering angle sensor, 3 ... Vehicle speed sensor, 4 ... Front wheel steering device, 6 ... Hydraulic steering device, 8 ... Steering handle, 9 ，
10...Front wheel, 11,12...Rear wheel, 〓...Yaw rate target value, ¨...Yaw angular acceleration target value,...
...Lateral acceleration target value, δ, δ〓...Optimum steering angle value, _F
...Front wheel steering angle target value.

Claims (1)

[Claims] 1. A steering wheel angle detection means for detecting a steering angle of a steering wheel; a vehicle speed detection means for detecting a vehicle speed; and one or more target vehicle models having a preset desired motion performance. By calculation,
motion variable target value calculation means for determining a plurality of target values of motion variables corresponding to the steering angle of the steering wheel and the vehicle speed; a plurality of steering angle optimum value calculating means for calculating an optimum value of a wheel steering angle of at least one of a front wheel or a rear wheel from a given one of the motion variable target values and the own vehicle specifications; steering angle target value calculating means for determining a target value of the wheel steering angle by applying a weighted average to the optimum steering angle value; 1. A steering angle control device for a vehicle, comprising a wheel steering means for steering the vehicle. 2. The motion variable target value calculation means includes a first target vehicle model for determining a target value of yaw rate and a second target vehicle model for determining a target value of lateral acceleration, and calculates the target value of yaw rate and 2. The vehicle steering angle control device according to claim 1, wherein a lateral acceleration target value is determined as a motion variable target value. 3. A patent characterized in that the motion variable target value calculation means includes one target vehicle model, and calculates a target value of yaw rate and a target value of lateral acceleration as motion variable target values based on the target vehicle model. A vehicle steering angle control device according to claim 1. 4. The motion variable target value calculation means includes a target vehicle model for determining a target value of yaw rate,
Find a yaw rate target value as a motion variable target value, and multiply the yaw rate target value by the vehicle speed V detected by the vehicle speed detection means, where V is the target value of the lateral acceleration, and the lateral acceleration target value 2. The vehicle steering angle control device according to claim 1, wherein the motion variable target value is also the motion variable target value. 5 The steering angle target value calculation means calculates functions f ₁ (V) and f ₂ (V) of the vehicle speed V (where f ₁ (V) + f ₂ (V)) based on the vehicle speed V detected by the vehicle speed detection means. )=1
)
and determines the optimum value of the wheel steering angle based on the yaw rate target value and the lateral acceleration target value. From the wheel steering angle optimum value δ obtained by the steering angle optimum value calculating means for calculating the optimum value of the steering angle, the target value of the vehicle steering angle is calculated as follows: = f ₁ (V) δ + f ₂ (V) δ The vehicle steering angle control device according to any one of claims 2 to 4, wherein the steering angle control device is determined by a weighted average. 6. The steering angle target value calculating means calculates the steering angular velocity θ〓 _S of the steering wheel based on the steering angle θ _S of the steering wheel detected by the steering wheel steering angle detecting means, and when θ〓 _S is large, g ₁ ( θ〓 _S )
1,
g ₂ (θ〓 _S ) becomes 0, and when θ〓 _S is small, g ₁ (θ〓 _S )
0,
_{The function g 1 (} θ〓
_S ) and
g ₂ (θ〓 _S ) to determine the optimum value of the wheel steering angle based on the target yaw rate value. From the wheel steering angle optimum value δ〓 obtained by the steering angle optimum value calculating means which calculates the optimum value of the wheel steering angle based on the target value, the target value of the wheel steering angle is calculated as =g ₁ (θ〓 _S ) δ〓+g ₂ (θ〓 _S )δ The vehicle steering angle control device according to any one of claims 2 to 4, wherein the steering angle control device is determined by a weighted average of δ〓+g 2 (θ〓 S )δ.