JP3212134B2 - Integrated vehicle 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 a high-performance turning system in which the influence of the distribution of driving force between front and rear wheels on a steering system is controlled by integrally controlling a vehicle steering system and a driving or braking system. The present invention relates to an integrated control device for a vehicle capable of obtaining characteristics.

[0002]

2. Description of the Related Art Conventionally, there is a technique for improving turning characteristics of a vehicle. For example, there is a "vehicle steering control device" (Japanese Patent Laid-Open No. 3-132166) for improving turning characteristics by generating an optimum steering angle on at least one of front and rear wheels of a vehicle. In this prior art, the linear control theory is applied by utilizing that the relationship between the actual steering angle of the front and rear wheels, which is the steering control amount, and the behavior amount representing the turning motion of the vehicle is represented by a linear differential equation, It realizes advanced turning characteristics. However, control using only the steering system has a limit in improving the turning characteristics. In other words, although some non-linear characteristics of the tire are compensated by the control, a sufficient control effect cannot be expected only by controlling the steering system in a region near the limit where the non-linear characteristics of the tire greatly affect. For this reason, research is being conducted in recent years to combine the control of the driving system in addition to the steering system to improve the turning characteristics in an integrated manner. In this case, the control performance is expected to be improved as compared with the control system design using only the steering system, particularly in a turning region near the limit where the tire characteristics are saturated.

[0003] As a conventional technique for integrating and controlling the distribution of driving force of a vehicle and the steering angle of a rear wheel, for example, "4.
Control Method of Wheel Drive, Distribution of Driving Force of Four-Wheel Steered Vehicle and Rear Wheel Steering Angle "(Japanese Patent Laid-Open No. 1-182129). This prior art,
"When equipped with a device that controls the rear wheel steering angle so that the rear wheel is steered in the same direction as the front wheel when steering the front wheel, the actual lateral acceleration detected by the lateral G sensor during front wheel steering, the front wheel steering angle and the vehicle speed If the difference between the calculated virtual lateral acceleration and the virtual lateral acceleration is equal to or greater than a certain set value, the driving to the front and rear wheels is performed according to the difference between the actual lateral acceleration and the virtual acceleration and the total driving force at that time. Correcting and controlling power distribution and rear wheel steering angle ".

[0004] In the prior art, a case-based algorithm is mainly used, and how to determine the magnitude of the correction amount of the steering angle and the torque distribution is not disclosed. However, if the magnitude of the correction amount is not appropriate, the vehicle motion is rather deteriorated, and a large amount of trial and error is indispensable for determining the correction amount in an actual design. That is, in the control algorithm according to the related art, for example, when the actual lateral acceleration is smaller than the target virtual lateral acceleration, the rear wheel driving force distribution is increased and the rear wheel steering angle is corrected in the oversteer direction. . However, if the correction amount is not appropriate, the turning characteristic is rather deteriorated. That is, if only the yaw rate does not occur lateral acceleration of Tokoro life near the limit of the tire occurs, the correction amount becomes excessive, there is a possibility of falling into a spin state. Further, there is a problem that it is difficult to obtain an optimal control law by a trial and error design as in the prior art.

Further, the relationship between the actual steering angle of the front and rear wheels, which is the steering control amount, and the behavior amount representing the turning motion of the vehicle is represented by a linear differential equation, whereas the driving force or the braking force representing the drive control amount is obtained. The relationship between the distribution ratio and the turning motion is not expressed as a linear differential equation, but as a nonlinear differential equation. For this reason,
When designing a control system that integrates a steering system and a drive system, linear control theory cannot be applied when trying to design a control system that directly inputs the steering control amount and the drive control amount. Therefore, there is a problem that it is difficult to obtain a target optimal control system.

[0006]

Therefore, the present inventors have improved a conventional control system design based on tuning, and applied a linear control theory to achieve a systematic control system design without trial and error. To solve the problem in the prior art.

That is, the influence of the distribution of the driving force between the front and rear wheels on the turning characteristics is nonlinear, and cannot be represented by a linear vehicle motion model. Therefore, a control system design for integrally controlling the steering system and the drive system must be based on a nonlinear vehicle motion model. However, the linear control theory can be applied only to a linear model, and cannot simply be applied to the design of an integrated steering and drive control system. Thus, the present inventors
Focusing on defining a new virtual control amount by variable conversion of the control amount of the steering system and the drive system so that the vehicle motion model becomes a linear model.

That is, an object of the present invention is to apply the linear control theory to the linear model derived in this way to perform integrated and optimal control of the steering system and the drive braking system.

[0009]

According to a first aspect of the present invention, there is provided a detecting device for detecting at least a steering wheel amount and a behavior amount representing a turning motion of a vehicle, and the detected steering amount. A linear control amount calculating means for linearly calculating a linear control amount for causing the behavior amount to follow an appropriate characteristic based on a linear model representing vehicle motion, and the calculated linear control amount according to the behavior amount. A non-linear compensation means for performing non-linear conversion based on the detected behavior amount and outputting a steering control amount and at least one of a drive control amount representing a drive characteristic and a braking control amount representing a braking characteristic; and a vehicle according to the steering control amount. A steering control means for generating an optimum steering angle on at least one of the front wheels and the rear wheels, and at least one of a driving force and a braking force in accordance with at least one of the driving control amount and the braking control amount. Those formed by and a drive brake control means for variably controlling the distribution of the wheel.

[0010]

The detecting means detects a steering amount and a behavior amount representing a turning motion of the vehicle and converts them into an electric signal corresponding thereto. Next, in order to optimize the behavior of the vehicle with respect to the steering amount in the linear control amount calculating means, a linear control amount, which is a virtual control amount, is linearly calculated from the steering amount and the behavior amount based on a linear model representing the vehicle motion.

The calculated linear control amount is nonlinearly converted by the non-linear compensation means using the behavior amount, so that the steering control amount and the drive control amount, which are direct control parameters of the steering system and the drive system, are obtained. By outputting at least one of the braking control amounts, the responsiveness and stability of the vehicle are efficiently improved.

Next, a steering actuator is driven based on the calculated steering control amount by the steering control means so as to give an optimum steering angle to at least one of the front wheels or the rear wheels.

The driving / braking control means drives a center differential multi-plate hydraulic clutch or a brake actuator based on at least one of the driving control amount and the braking control amount calculated by the driving / braking control means, thereby driving and braking the front and rear wheels. At least one of the distribution ratios is variably controlled.

[0014]

According to the present invention, a linear control amount obtained by a nonlinear variable conversion from a steering control amount, a drive control amount, and a braking control amount is introduced as a virtual control amount, and the control using the linear control amount as a control input. Design the system. in this case,
Since the behavior amount and the linear control amount have a relationship of a linear differential equation described by a transfer function, it is possible to apply the linear control theory, and the linear control amount can be relatively easily calculated from the steering amount and the behavior amount. In this case, a linear control amount calculating means can be designed.

As described above, according to the present invention, since the linear control theory can be applied, the control of the steering system, the drive, and the control system can be performed in an integrated manner based on the linear model. The design is performed, and the turning characteristics can be optimally controlled in a wide range from the normal turning range to the limit range of the tire that cannot be achieved by the control of the steering system alone.

(Other Description of the Invention) Claim 2 of the present invention
The second invention, which embodies an example of the first invention described above, performs target control for calculating a target control amount for achieving a target vehicle behavior amount based on the detected steering amount. An amount calculating means, a target behavior amount calculating means for calculating a target vehicle behavior amount based on the detected steering amount, and a behavior amount based on the calculated target behavior amount and the detected behavior amount. Correction amount calculating means for linearly calculating a correction amount for following the target behavior amount based on a linear model representing vehicle motion, and a control amount for calculating the control amount by adding the target control amount and the correction amount calculated in the previous period. And arithmetic means.

The operation of the vehicle integrated control device according to the second aspect of the present invention having the above-described structure is as follows. In the target control amount calculating means, in order to optimize the behavior of the vehicle with respect to the steering amount, the target control amount required to achieve the target vehicle behavior amount is calculated from the steering amount in consideration of the linear vehicle motion characteristics. I do. This target control amount acts as a feedforward control amount in controlling the behavior amount among the virtual control amounts defined for applying the linear control theory, and improves the responsiveness of the vehicle to steering. Further, the target behavior amount calculation means calculates a target behavior amount which is a behavior amount of a target vehicle.

Next, the correction amount calculating means calculates an optimum correction amount for suppressing the deviation between the detected actual behavior amount and the target behavior amount in consideration of the linear vehicle motion characteristics. This correction amount acts as a feedback control amount in controlling the behavior amount among the virtual control amounts defined for applying the linear control theory, thereby improving the stability of the vehicle. The correction amount calculating means is systematically optimally designed by applying the linear control theory.

Then, in the control amount calculating means, a target control amount acting as a feedforward control amount and a correction amount acting as a feedback control amount in controlling the behavior amount are added to form a virtual control amount. Calculate the linear control amount.

The linear control amount calculated by the non-linear compensation means is non-linearly converted by using the behavior amount, so that the steering control amount and the drive control, which are direct control parameters of the steering system and the driving / braking system, are obtained. Outputs at least one of the amount and the braking control amount to efficiently improve the responsiveness and stability of the vehicle.

Next, the steering control means drives the steering actuator based on the calculated steering control amount so as to give an optimum steering angle to at least one of the front wheels or the rear wheels.

The driving / braking control means drives a center differential multi-plate hydraulic clutch, a brake actuator, or the like based on at least one of the driving control amount and the braking control amount calculated as described above, thereby driving or braking the front and rear wheels. The distribution ratio is variably controlled.

Focusing on the control of the behavior amount, if there is no fluctuation of vehicle specifications or disturbance from the external environment, the behavior amount is controlled by the target control amount which is a feedforward control amount in the behavior amount control. Therefore, the deviation becomes zero, the correction amount which is a feedback control amount in controlling the behavior amount also becomes zero, and the feedback control does not work.

On the other hand, when there are fluctuations in vehicle specifications, disturbances from the external environment, and the like, a target amount of behavior cannot be obtained only by feedforward control, and a deviation occurs. In this case, the correction amount corresponding to the deviation is output from the correction amount calculating means. This correction amount works to make the deviation asymptotic to zero, so that the dynamic characteristics of the vehicle can asymptotically approach the target behavior amount.

As described above, in the vehicle integrated control apparatus according to another aspect of the present invention, the target control amount calculating means for calculating the target control amount which is a feedforward control amount for improving the response of the behavior amount to the steering is provided. The correction amount calculating means for calculating the correction amount, which is a feedback control amount for improving stability against fluctuations in vehicle specifications and disturbances from the external environment, can be individually designed. There is no need to consider the effects and each control system design is easier to do.

[0026]

Embodiment 1 An embodiment in which the integrated control device for a vehicle of the present invention is applied to a vehicle capable of variably controlling a rear wheel steering angle and a driving force distribution ratio will be described as Embodiment 1 with reference to FIGS. 1 and 2. . First, an example of a nonlinear model describing an integrated steering and drive system including a nonlinear effect of a drive control amount on a turning motion will be specifically described with reference to FIG.
In the following description, the time derivative of the function x is represented as x '.

FIG. 1 shows the relationship between the slip angle of each wheel and the generated cornering force. The cornering force generated at each wheel has a relationship substantially proportional to the slip angle of each wheel, but when a driving force or a braking force is applied to the tire, the cornering power, which is a proportional constant, decreases. The present invention utilizes this property for controlling the amount of behavior of the vehicle such as turning characteristics. That is, when the distribution of the driving and braking forces during acceleration / deceleration is set to be large for the front wheels, the cornering force of the front wheels to which the driving and braking forces are applied is reduced, and has the same effect as returning the steering angle of the front wheels. Also,
When the distribution of driving and braking forces during acceleration / deceleration is set to be large for the rear wheels, the cornering force of the front wheels to which driving and braking forces are not applied does not decrease, whereas the cornering force of the rear wheels to which driving and braking forces are applied decreases. This has the same effect as returning the steering angle of the rear wheels. Eventually, the vehicle motion considering these phenomena can be described using the following equation.

Mv (β ′ + R) = Ff + Fr (1) Iz R ′ = af Ff−ar Fr (2) Ff = −cf (β + af R / v−δf) · ・ 1-hf | T | ( 1 + λ)｝ (3) Fr = −cr (β-arR / v−δr) ・ {1-hr | T | (1-λ)} (4)

Where, af, ar: distance between the axles of the front and rear wheels and the center of gravity cf, cr: cornering power of front and rear wheels when no driving or braking force is applied Ff, Fr: cornering force of front and rear wheels Iz: yaw Moment of inertia m: vehicle mass R: yaw angular velocity T: total driving force (a negative value indicates braking force) v: vehicle speed β: body slip angle δf, δr: actual steering angle of front and rear wheels

Also, hf | T | (1 + λ) and hr |
T | (1−λ) is a term representing a decrease in cornering power due to driving and braking forces. (However, hf and hr are coefficients.) Λ (−1 ≦ λ ≦ 1) is a value related to the drive system control, λ = 1 means that all the driving force and braking force are applied to the front wheels, and λ = -1 corresponds to applying all the driving force and the braking force to the rear wheels.

FIG. 2 shows an integrated control device for a vehicle according to this embodiment. The vehicle speed detecting means includes a vehicle speed sensor 110,
The vehicle speed is estimated and calculated from the rotation speed of the wheels, and a corresponding electric signal is output as a vehicle speed signal v.

The steering amount detecting means comprises a steering angle sensor 120 mounted coaxially with the steering wheel, measures the steering angle of the steering wheel, divides the steering angle by a value corresponding to the steering wheel gear ratio, and outputs a steering wheel amount signal of the driver. Output as δ sw . Since the front wheel steering angle control is not performed in the first embodiment, δf = δsw .

The behavior amount detecting means includes a vehicle body slip angle sensor 131, a yaw angular velocity sensor 132, and a total driving force sensor 13.
3 The vehicle body slip angle sensor 131 uses a non-contact type speedometer, and converts a vehicle body slip angle into an electric signal and outputs it as a vehicle body slip angle signal β. The vehicle body slip angle may be calculated from the lateral acceleration sensor and the vehicle speed and the yaw angular speed, and may be an estimated value. In this case, although the estimation accuracy of the vehicle body slip angle is not high, there is no need to use a non-contact type speed meter, and the system becomes more practical. Also, the yaw angular velocity sensor 132
Is attached to the center of gravity of the vehicle, measures the yaw angular velocity at the position of the center of gravity, and outputs it as a yaw angular velocity signal R. Further, the total driving force sensor 133 estimates the total driving force applied to the front and rear wheels from the throttle opening, the gear ratio, and the like, and outputs the total driving force signal T.

A linear control amount calculating unit 201 including a target control amount calculating unit 211, a target behavior amount calculating unit 221, a correction amount calculating unit 231, and a control amount calculating unit 241;
The nonlinear compensator 301 receives a vehicle speed signal, a steering amount signal, and a behavior amount signal, and outputs a rear wheel actual steering angle signal δr as a steering control amount signal and a driving force distribution ratio signal λ as a drive control amount signal. It is composed of a computer.

The contents of the calculations in the linear control amount calculation means 201 and the nonlinear compensation means 301 will be described below.

The characteristic of the yaw angular velocity represented by the equations (2) to (4) is the actual rear wheel steering angle δr as a direct control amount.
And the driving force distribution ratio λ is variable-converted into a virtual control amount p represented by the following equation to linearize it.

P = δr− (afcf ) / ( arcr) · hf | T | · (1 + λ) · (β + afR / v−δf) + hr | T | · (1-λ) · (β-arR / V-δr) + ｛ (af cf ) / ( ar cr ) -1 ｝ · β (5)

That is, the motion equation relating to the yaw angular velocity R is linearized by the new virtual control amount p as follows.

R ′ = − (af ² cf + ar ² cr) / (Iz v) · R + (af cf / Iz) · δf− (ar cr / Iz) · p (6)

In this embodiment, the linear control amount calculating means 201
Is designed based on the linear model of the equation (6), and the nonlinear compensation means 301 is designed based on the variable transformation of the equation (5). The target behavior amount calculation means 221 outputs, as a target behavior amount signal, a target yaw angular velocity R0, which is a vehicle behavior amount at which the driver can easily steer based on the vehicle speed signal v from the steering amount signal δf. Here, as such a dynamic characteristic of the vehicle behavior, a characteristic in which the yaw angular velocity follows the steering with a first-order delay is considered. Next, the driver's steering wheel steering amount signal δ s
w = δ f , and shows a mathematical expression representing the relationship between the vehicle speed signal v and the target yaw angular velocity signal R0. R0 = vδf / {(af + ar) · (1 + τ1 s)} (7)

Here, τ1 is a first-order time constant, and s is a Laplace operator. The operation of the expression (7) is discretized and operated as a recurrence expression. The target control amount calculation means 211 calculates a virtual control amount p necessary for obtaining the target yaw angular velocity R0 as the target vehicle behavior amount as a target control amount signal pf which is a feedforward control amount for the behavior amount. I do.

Next, the calculation contents of the target control amount calculation means 211 will be described. Here, the design is performed based on the equation (6) linearized by the variable transformation. That is,
The virtual control amount p required to make equation (6) match the desired characteristic of equation (7) is given by the following equation.

[0043] p = k1 δf-k2 · ( 1 + τ2s) / (1 + τ1s) · δf ... (8) However, k1 = (af cf) / (ar cr) k2 = (af + ar) / (af 2 ar cf cr + ar 3 cr ^{2) ... (9) τ2 =} Iz v / (af 2 cf + ar 2 cr) ... (10) Therefore, the computation of the target control quantity computation unit 21 1,
The equations (8) to (10) are discretized, and the calculated p is output as the target control amount signal pf.

The correction amount calculating means 231 is a feedback control amount for a behavior amount such that the deviation signal R0-R between the target yaw angular velocity signal R0 and the yaw angular velocity signal R gradually approaches zero. The correction amount signal pb is calculated and output. The algorithm of this operation is a control law with the linear state equation of equation (6) as the control target. That is,
Since the equation (6) is a linear equation of state, it is possible to apply the linear control theory. In the case of the present embodiment, the correction amount signal pb is calculated based on the state equation shown by the following equation derived by applying the linear control theory.

Xc ′ = Acxc + Bc · (R0−R) (11) pb = Ccxc + Dc · (R0−R) (12) where Ac, Bc, Cc and Dc are constant matrices. In this case, the control law includes dynamic characteristics, and this control law is discretized into a recurrence formula. Further, the control law may be state feedback.

The control amount calculating means 241 includes a target control amount signal pf which is a feed-forward control amount calculated by the target control amount calculating means 211 and a correction amount calculating means 2.
A correction amount signal pb, which is a feedback control amount calculated in 31, is added, and a linear control amount signal pf + pb is added.
Is output.

The nonlinear compensating means 301 calculates the vehicle speed sensor 110 from the linear control amount signal p obtained by the control amount calculating means.
The vehicle speed signal v and the vehicle body slip angle sensor 131
And the yaw angle sensor 1
32 and the total driving force sensor 1
Based on the total driving force signal T obtained from 33, a rear wheel actual steering angle signal δr as a steering control amount signal and a driving force distribution ratio signal λ as a drive control amount signal are calculated and output.

Next, the contents of the calculation in the nonlinear compensation means 301 will be described. Linear control amount signal pf + pb
And the rear wheel actual steering angle signal δr and the driving force distribution ratio signal λ, the relationship between p and δr, λ shown in the equation (5) holds. However, it is indeterminate to solve for the rear wheel actual steering angle δr and the driving force distribution ratio λ only from equation (5), and these signals, that is, the rear wheel actual steering angle signal δr and the driving force distribution ratio signal λ are uniquely determined. I can't. For this reason,
Here, the rear wheel actual steering angle δr and the driving force distribution ratio λ are derived by the following algorithm.

That is, first, increasing the driving force distribution ratio λ (approaching the front wheel drive) contributes to suppressing the output of the yaw angular velocity, and decreasing the driving force distribution ratio (approaching the rear wheel drive). Focuses on increasing the output of the yaw angular velocity, and calculates the driving force distribution ratio λ as shown in the following equation. λ = sgn (R) · K · | T | · (pf + pb) (13) where K is a positive constant and sgn (R) means the sign of R. In addition, the fact that the total driving force T is included in this equation means that the weight of control of the drive system is small during constant-speed running where the influence of the drive system on the turning characteristics is small, and the influence of the drive system on the turning characteristics is small. This means that the weight of control of the drive system is increased when the vehicle is running at a high acceleration. In other words, the control law is such that λ does not change much during constant speed running with a small value of T, and greatly changes during acceleration running with a large value of T, so that the driving force distribution ratio is effectively used.

Then, by substituting λ of equation (13) into equation (5), δ
The actual steering angle of the rear wheel is obtained by solving for r. δr = ｛ar crp− (af cf −ar cr) β + af cf hf | T | (1 + λ) αf −ar cr hr | T | (1−λ) αr｝ / ｛ar cr −ar cr hr | T | (1−λ)｝ (14) where p = pf + pbαf = β + afR / v−δfαr = β-arR / v.

It is necessary to uniquely determine the rear wheel actual steering angle δr and the driving force distribution ratio λ by such an algorithm.
Not only is the performance of the control for setting the behavior amount to the desired characteristic improved, but also the efficiency of the control is improved. The steering control means comprises a rear wheel steering actuator 41 for giving a rear wheel a steering angle corresponding to δr based on a rear wheel actual steering angle signal δr as a steering control amount signal. The drive control means comprises a drive actuator 51 that variably controls the hydraulic pressure of the center differential hydraulic multiple disc clutch based on a drive force distribution ratio signal λ as a drive control amount signal.

The operation and effect of this embodiment having the above configuration are as follows. First, the outputs of the vehicle speed sensor 110, the steering angle sensor 120, the vehicle body slip angle sensor 131, the yaw angular velocity sensor 132, and the total driving force sensor 133 are input to a digital computer constituting the linear control amount calculating means 201 and the nonlinear compensating means 301. .

In the digital computer, first, the target yaw angular velocity R0, which is the target vehicle behavior amount, is calculated by the target behavior amount calculation means 221 according to the recurrence formula obtained by discretizing Expression (7).

In the target control amount calculating means 211, the dynamic characteristics of the vehicle behavior can be most easily controlled by the driver (7).
The virtual control amount p required to change to the dynamic characteristics of the equation
Is calculated as a target control amount pf according to a recurrence formula obtained by discretizing Expressions (8) to (10).

It should be noted that the target behavior amount follows a dynamic characteristic that makes it easy for the driver to steer. If there is no disturbance from the external environment such as fluctuation of vehicle specifications or cross wind disturbance, the behavior amount is the target behavior amount. Matches.

Next, in the correction amount calculating means 231,
Discretize equations (11) and (12) from the correction signal pb required to make the deviation between the target behavior and the measured value of behavior be asymptotic to zero due to fluctuations in vehicle specifications and disturbance from the external environment. Calculate according to the recurrence formula. With this correction amount signal, the dynamic characteristics of the vehicle behavior can be made to follow the target dynamic characteristics even when there are fluctuations in vehicle specifications and disturbance from the external environment.

Next, in the control amount calculating means 241,
The target control amount signal pf and the correction amount signal pb are added to output a linear control amount signal pf + pb.

Next, in the nonlinear compensation means 301,
Linear control amount signal pf + for obtaining a desired target behavior amount
Let pb be p, and convert to a rear wheel actual steering angle signal δr as a steering control amount signal and a driving force distribution ratio signal λ as a drive control amount signal according to equations (13) and (14). Here, (1
By including the total driving force T in the variable conversion of the equation (3), a control system for efficiently coordinating the steering system and the driving system is configured. That is, at the time of constant speed running in which the drive system has little effect on the turning characteristics, the value of T becomes small, so that the control of the drive system does not work and the hydraulic multi-plate clutch in the center differential is not operated unnecessarily. Further, during acceleration running in which the driving system has a large effect on the turning characteristics, the value of T becomes large, so that the control of the driving system is effectively used.

As described above, in this embodiment, the linear control amount calculating means 201 does not directly calculate the actual control parameters δr and λ, but calculates the linear control amount pf + pb. Is the steering control amount δ
r and the drive control amount λ.

For this reason, the control object viewed from the linear control amount calculating means 201, that is, the linear control amount pf + pb = p
Is input and the yaw rate R is output.
By linearly approximating the equation (6) and applying the linear control theory, it is possible to easily derive a control law for optimizing the characteristic of the yaw angular velocity.

Further, in this embodiment, in order to improve the characteristic of one behavior amount of the yaw angular velocity, two independent control amounts of the rear wheel actual steering angle and the driving force distribution ratio are used. For this reason, one degree of freedom becomes redundant, but the nonlinear compensating means 301 effectively utilizes this degree of freedom and efficiently distributes control to the steering system and the drive system in accordance with the motion state of the vehicle. We provide an energy-saving control system that eliminates unnecessary movement.

The target behavior amount (7) in this embodiment is set so that the low frequency gain of the yaw angular velocity is equal to that of a normal 2WS vehicle exhibiting neutral steering characteristics. For this reason, the driver can steer without feeling uncomfortable, and since the yaw angular velocity follows the steering with a first-order delay, stable running without overshoot is possible.

[0063]

Second Embodiment A second embodiment in which the vehicle integrated control device of the present invention is applied to a vehicle capable of variably controlling the front and rear wheel steering angles and the driving force distribution ratio will be described with reference to FIG. In this embodiment, as a non-linear model describing the integrated steering and drive system including the non-linear effect of the drive control amount on the turning motion, the same (1) to (4) as in the first embodiment.
And the use of the formula, In the following description, the transposed matrix of the matrix Y represents the Y ^T. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The steering amount detection means comprises a steering angle sensor 120 mounted coaxially with the steering wheel, measures the steering angle of the steering wheel, divides the steering angle by a value corresponding to the steering wheel gear ratio, and outputs a steering wheel steering amount signal of the driver. Output as δsw.

In the second embodiment, δsw is a control signal for controlling the front wheel actual steering angle δf.

The contents of the calculations in the linear control amount calculating means 202 and the nonlinear compensating means 302 will be described below.

The vehicle motion characteristics expressed by the equations (1) to (4) are expressed by the actual front and rear wheel steering angles δf,
Linearization is performed by converting δr and the driving force distribution ratio λ into virtual control amounts δf * and δr * represented by the following equations. δf * = δf + hf | T | · (β + afR / v−δf) · (1 + λ) (15) δr * = δr + hr | T | · (β-arR / v−δr) · (1-λ) … (16) That is, the equations of motion relating to the vehicle body slip angle and the yaw angular velocity are expressed by the new virtual control amounts δf * and δr *.
It is linearized as follows:

X ′ = A0 x + B0 u (17) where x = [β, R] ^T (18) u = [δf *, δr *] ^T (19) A0 = [A1, A2] (19) 20) A1 = [− (cf + cr) / (mv), (ar cr-af cf) / Iz] ^T A2 = [− 1− (af cf-ar cr) / (mv ² ), − (af ² cf + ar ²⁾ cr) / (Iz v)] ^T B0 = [B1, B2] (21) B1 = [cf / (mv), acf / Iz] ^T B2 = [cr / (mv), −ar cr / Iz] ^T This model uses δf *, δr as virtual inputs.
When * is replaced with the actual steering angles δf, δr of the front and rear wheels, respectively, the linear model of 4WS is usually handled. In the present embodiment, the linear control amount calculation means 202 adds the nonlinear compensation means 302 to the linear model represented by the equations (17) to (21).
Is designed based on the variable conversion of the equations (15) and (16).

The target behavior amount calculation means 222 uses the target vehicle body slip angle β0 and the target yaw angular velocity R0 as the target behavior amount signals, which are the vehicle behavior amounts at which the driver can easily steer based on the vehicle speed signal v from the steering amount signal δsw. Output. Here, as such dynamic characteristics of the vehicle behavior, a characteristic is considered in which the vehicle body slip angle always follows zero and the yaw angular velocity follows the steering with a first-order lag. Next, the steering amount signal δsw, the vehicle speed signal v, the target vehicle body slip angle signal β, and the target yaw angular speed signal R
Here is an equation that represents the relationship of 0. β0 = 0 (22) R0 = vδsw / ｛(af + ar) · (1 + τ1s)｝ (23) where τ1 is a first-order time constant and s is a Laplace operator. The operation of the expression (23) is discretized and calculated as a recurrence expression.

The target control amount calculation means 212 is a virtual control amount δf *, δr * necessary for obtaining the target vehicle body movement amount, ie, the target vehicle body slip angle β0 and the target yaw angular velocity R0.
Are calculated as target control amounts Δf * f and Δr * f, which are feedforward control amounts for the behavior amount.

Next, the calculation contents of the target control amount calculation means 212 will be described. Here, the design is performed based on equations (17) to (21) linearized by variable conversion. By the way, the relationship between the virtual control amounts δf *, δr * and the behavior amount in the expressions (17) to (21) is expressed by (22),
In order to obtain the target dynamic characteristic represented by the equation (23), the steering wheel amount δsw of the driver and the virtual control amount δf
The following dynamic characteristics are required between * and δr *. δf * = (α1 s + α2) / (α3 s + α4) · δsw (24) δr * = (α3 s + α4) / (1 + τ1 s) · δsw (25) α1 = Iz / {cf (af + ar) ² } · v (26) α2 = af / (af + ar) + arm / ｛cf (af + ar) ² ｝ · v ² (27) α3 = −Iz / ｛cr (af + ar) ² ｝ · v (28) α4 = −ar / ( af + ar) + af m / {cr (af + ar) ² } · v ² (29)

Therefore, the target control amount calculating means 212
Is to discretize equations (24) to (29) and convert δf * to δf * f, δr *
Is calculated as Δr * f and output as a target signal.

The correction amount calculating means 232 outputs a deviation signal β0 between the target vehicle body slip angle signal β0 and the vehicle body slip angle signal β.
-Β, the target yaw angular velocity signal R0 and the yaw angular velocity signal R
The correction signals .delta.f * b, .delta.r * b, which are feedback control amounts, are calculated and output from the deviation signals R0 -R from the above. The algorithm of this operation is a control law that uses the linear state equation of equations (17) to (21) as a control target. That is, (17)
Equations (21) to (21) are linear equations of state, so that the linear control theory can be applied. In the case of the present embodiment, the correction amount signals Δf * b and Δr * b are calculated based on the following state equation derived by applying the linear control theory.

[0074] xc '= Ac xc + Bc yc ... (30) uc = Cc xc + Dc yc ... (31) However, uc = [δf * b, δr * b] T yc = [β0-β, R0-R] be the ^T , Ac, Bc, Cc, and Dc are constant matrices. In this case, the control law includes dynamic characteristics, and this control law is discretized into a recurrence formula. Further, the control law may be state feedback.

The control amount calculating means 242 calculates the target control amount signals δf * f, δr * f, which are the feedforward control amounts calculated by the target control amount calculating means 212, and calculates the correction amount calculating means 232. The correction amount signals Δf * b and Δr * b, which are feedback control amounts, are added, and linear control amount signals Δf * f + δf * b and Δr * f + δr * b are output.

The nonlinear compensating means 302 calculates the vehicle speed signal v obtained from the vehicle speed detecting means 110 from the linear control amount signals δf * and δr * obtained from the control amount calculating means and the vehicle body obtained from the vehicle body slip angle sensor 131. Based on the slip angle signal β, the yaw angular velocity signal R obtained from the yaw angular velocity sensor 132 and the total driving force signal T obtained from the total driving force sensor 133, the front wheel actual steering angle signal δf as the steering control amount signal, and the rear wheel An actual steering angle signal δr and a driving force distribution ratio signal λ as a driving control amount signal are calculated and output.

Next, the contents of the calculation in the nonlinear compensating means 302 will be described. Linear control amount signal δf * f + δ
f * b, δr * f + δr * b and the front wheel actual steering angle signal δf, the rear wheel actual steering angle signal δr, and the driving force distribution ratio signal λ,
The relationship between δf *, δr * and δf, δr, λ shown in the equation (6) holds. However, it is indeterminate to solve for the front wheel actual steering angle signal Δf, the rear wheel actual steering angle Δr, and the driving force distribution ratio λ only from equations (15) and (16), and these signals cannot be uniquely determined. Therefore, here, the front wheel actual steering angle signal δf, the rear wheel actual steering angle δr, and the driving force distribution ratio λ are derived by the following algorithm.

That is, first, increasing the driving force distribution ratio λ (approaching front wheel driving) contributes to suppressing the output of the yaw angular velocity, and decreasing the driving force distribution ratio (approaching rear wheel driving). Focuses on increasing the output of the yaw angular velocity, and calculates the driving force distribution ratio λ as shown in the following equation.

Λ = sgn (R) · K · | T | · (R−R0) (32) where K is a positive constant and sgn (R) means the sign of R. In addition, the fact that the total driving force T is included in this equation means that the weight of control of the drive system is small during constant-speed running where the influence of the drive system on the turning characteristics is small, and the influence of the drive system on the turning characteristics is small. This means that the weight of control of the drive system is increased when the vehicle is running at a high acceleration. In other words, the control law is such that λ does not change much during constant speed running with a small value of T, and greatly changes during acceleration running with a large value of T, so that the driving force distribution ratio is effectively used.

Then, the actual steering angles of the front wheels and the rear wheels are obtained by substituting λ of the equation (32) into the equations (15) and (16) and solving for δf and δr. δf = {δf * -hf | T | · (β + af R / v) · (1 + λ)} / {1-hf | T | · (1 + λ)} (33) δr = ｛δr * -hr | T | · (Β-ar R / v) · (1-λ)｝ / {1-hr | T | · (1-λ)} (34) where δf * = δf * f + δf * b, δr * = δr * f + δr * b

By uniquely determining the front wheel actual steering angle δf, the rear wheel actual steering angle δr, and the driving force distribution ratio λ by such an algorithm, the performance of control for setting the behavior amount to desirable characteristics is improved. Not only that, but also the efficiency of the control is improved.

The steering control means includes a front wheel steering actuator 41 for giving a turning angle corresponding to δf to the front wheels based on a front wheel actual steering angle signal δf as a steering control amount signal, and a rear wheel steering wheel based on a rear wheel actual steering angle signal δr. And a rear wheel steering actuator 42 for giving a steering angle corresponding to δr to the rear wheel.

The drive control means variably controls the hydraulic pressure of the center differential hydraulic multi-plate clutch based on the drive force distribution ratio signal λ as the drive control amount signal.
Consists of

The operation and effect of this embodiment having the above configuration are as follows. First, the outputs of the vehicle speed sensor 110, the steering angle sensor 120, the vehicle body slip angle sensor 131, the yaw angular velocity sensor 132, and the total driving force sensor 133 are input to a digital computer constituting the linear control amount calculating means 202 and the nonlinear compensating means 302. .

In the digital computer, first, according to the recurrence formula obtained by discretizing the equations (22) and (23) in the target behavior amount calculating means 222, the target vehicle body slip angle β0 and the target vehicle behavior angle are obtained. The target yaw angular velocity R0 is calculated.

In the target control amount calculating means 212, the dynamic characteristics of the vehicle behavior are most easily controlled by the driver (2
The virtual control amounts δf * and δr * necessary to change to the dynamic characteristics of equations (2) and (23) are defined as target control amounts δf * f and δr * f as (2
The calculation is performed according to the recurrence formula obtained by discretizing Formulas 4) to (29).

Note that the target behavior amount follows the dynamic characteristic that makes it easy for the driver to steer. If there is no disturbance from the external environment such as fluctuation of vehicle specifications or cross wind disturbance, the behavior amount is the target behavior amount. Matches.

Next, in the correction amount calculating means 232,
The correction amount signals δf * b and δr * b required to make the deviation between the target behavior amount and the measured value of the behavior amount caused by fluctuations in vehicle specifications or disturbance from the external environment asymptotic to zero are (30), ( 31) Calculate according to the recurrence formula which made the formula discretized. With this correction amount signal, the dynamic characteristics of the vehicle behavior can be made to follow the target dynamic characteristics even when there are fluctuations in vehicle specifications and disturbance from the external environment.

Next, in the control amount calculating means 242,
Target control amount signals δf * f, δr * f and correction amount signals δf * b, δr *
b, and the linear control amount signal δf * f + δf * b, δr * f + δ
Output r * b.

Next, in the nonlinear compensation means 302,
Linear control signal δf * f for obtaining desired target behavior
+ Δf * b, δr * f + δr * b as δf *, δr *,
According to equation (34), the signals are converted into a front wheel actual steering angle signal δf as a steering control amount signal, a rear wheel actual steering angle signal δr, and a driving force distribution ratio signal λ as a drive control amount signal. Here, (3
By including the total driving force T in the variable conversion of the expression 2), a control system for efficiently coordinating the steering system and the driving system is configured. That is, at the time of constant speed running in which the drive system has little effect on the turning characteristics, the value of T becomes small, so that the control of the drive system does not work and the hydraulic multi-plate clutch in the center differential is not operated unnecessarily. Further, during acceleration running in which the driving system has a large effect on the turning characteristics, the value of T becomes large, so that the control of the driving system is effectively used.

As described above, in this embodiment, the linear control amount calculating means 202 calculates the actual control parameters δf, δr,
Instead of directly calculating λ, linear control amount δf * f + δf *
b, δr * f + δr * b is calculated, and is converted into steering control amounts δf, δr and drive control amount λ by the non-linear compensation means 302.

For this reason, the control object viewed from the linear control amount calculating means 202, that is, the linear control amount δf * f + δf * b
= Δf *, δr * f + δr * b = δr *, and the system that outputs the vehicle body slip angle β and the yaw angular velocity R are (1
By linearly approximating as in equations (7) to (21) and applying the linear control theory, it is possible to easily derive a control law for optimizing the characteristics of the vehicle motion. Also, (1
Equations (7) to (21) are 4WS linear models that are usually handled when δf * and δr * as virtual inputs are replaced with actual steering angles δf and δr of the front and rear wheels, respectively. For this reason, the linear control amount calculation means 202 uses the 4WS that is normally handled.
Although it is possible to use the controller as it is,
In this embodiment, the influence of the driving force distribution on the turning characteristics is taken into consideration. In this case, a higher-performance control system is realized despite the use of the same controller.

Further, in this embodiment, in order to improve the characteristics of the two behavioral quantities of the vehicle body slip angle and the yaw angular velocity, three independent control quantities of the front wheel actual steering angle, the rear wheel actual steering angle and the driving force distribution ratio are used. Is used. For this reason, one degree of freedom is redundant, but the nonlinear compensating means 302 effectively utilizes the degree of freedom and efficiently distributes control to the steering system and the drive system in accordance with the motion state of the vehicle. We provide an energy-saving control system that eliminates unnecessary movement.

In this embodiment, equations (22) and (23) are used as the vehicle behavior characteristics that make it easy for the driver to steer. However, by setting the vehicle body slip angle to zero as in equation (22), The driver can operate safely without being alert for the spin. However, there are some drivers who feel uncomfortable because the characteristics of equation (22) are greatly different from those of a normal 2WS vehicle. In this case, the problem is solved by making the characteristics of the vehicle body slip angle proportional to the vehicle speed and following the steering with a first-order delay instead of the expression (22). In equation (23), since the low-frequency gain of the yaw angular velocity is set equal to that of a normal 2WS vehicle exhibiting neutral steering characteristics, the driver can steer without feeling uncomfortable, and has a first order with respect to steering. Since the vehicle follows the vehicle with a delay, stable running without overshoot is possible. In this embodiment,
The low-frequency gain of the yaw angular velocity is set so as to show the neutral steer characteristic. However, this can be set to the over-steer characteristic or the under-steer characteristic by setting the change of the low-frequency gain depending on the vehicle speed.

[0095]

Third Embodiment A third embodiment in which the integrated vehicle control apparatus of the present invention is applied to a vehicle in which the front wheel steering angle and the driving force distribution ratio can be variably controlled will be described with reference to FIG. First, the nonlinear model used in the present embodiment will be described. In the present embodiment, since the steering angle of the rear wheel is always zero, the non-linear model representing the vehicle motion sets the rear wheel actual steering angle δr of the equations (1) to (4) shown in the first embodiment to zero. It can be described by the following equation.

Mv (β ′ + R) = Ff + Fr (35) IzR ′ = af Ff−ar Fr (36) Ff = −cf (β + af R / v−δf) · ・ 1-hf | T | ( 1 + λ)｝ (37) Fr = −cr (β-ar R / v) · {1-hr | T | (1-λ)} (38)

FIG. 4 shows an integrated control device for a vehicle according to this embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The steering amount detecting means is composed of a steering angle sensor 120 mounted coaxially with the steering wheel, and measures the steering angle of the steering wheel and divides the steering angle by a value corresponding to the steering wheel gear ratio, similarly to the second embodiment. , The value corresponding to the front wheel actual steering angle is used as the steering wheel steering amount signal δsw of the driver.
Output as

The behavior amount detecting means is the same as in the second embodiment, and comprises a vehicle body slip angle sensor 131, a yaw angular velocity sensor 132, and a total driving force sensor 133. Linear control amount calculating means 203 including a target control amount calculating means 213, a target behavior amount calculating means 223, a correction amount calculating means 233, and a control amount calculating means 243;
Is composed of a digital computer that inputs a vehicle speed signal, a steering amount signal, and a behavior amount signal, and outputs a front wheel actual steering angle signal δf as a steering control amount signal and a driving force distribution ratio signal λ as a drive control amount signal. .

The contents of the calculations in the linear control amount calculating means 203 and the nonlinear compensating means 303 will be described below. (36)
The characteristic of the yaw angular velocity expressed by the equation (38) is to convert the front wheel actual steering angle δf and the driving force distribution ratio λ as direct control variables into a virtual control quantity q shown in the following equation. Is linearized by

Q = δf + hf | T | · (1 + λ) · (β + af R / v−δf) − (ar cr ) / ( af cf) · hr | T | · (1-λ) · (β-ar R / v) + ｛ (ar cr ) / ( af cf ) -1 ｝ · β (39) That is, the motion equation relating to the yaw angular velocity R is linearized by the new virtual control amount q as in the following equation. . ^{R '= - (a f 2} cf + a r 2 cr) / (1z v) · R + (af cf / Iz) · q ... (40) In the present embodiment, the linear control amount calculating means 203, (40)
The non-linear compensation means 303 is designed based on the variable conversion of the equation (39) in the linear model of the equation.

The target behavior amount calculating means 223 outputs the target yaw angular velocity R0, which is the vehicle behavior amount that makes the driver most easy to steer, as the target behavior amount signal based on the steering amount signal δsw and the vehicle speed signal v. Here, as such a dynamic characteristic of the vehicle behavior, a characteristic in which the yaw angular velocity follows the steering with a first-order delay is considered. Next, a mathematical expression showing the relationship between the steering amount signal δsw, the vehicle speed signal v, and the target yaw angular velocity signal R0 is shown. R0 = vδsw / ｛(af + ar) ・ (1 + τ1s)｝ (41)

Here, τ1 is a first-order time constant, and s is a Laplace operator. The calculation of the expression (41) is discretized and calculated as a recurrence expression. The target control amount calculating means 213 calculates a virtual control amount q necessary for obtaining a target yaw angular velocity R0 as a target vehicle behavior amount as a target control amount signal qf which is a feedforward control amount for the behavior amount. I do.

Next, the calculation contents of the target control amount calculation means 213 will be described. Here, the design is performed based on the equation (40) linearized by the variable transformation. That is, (4
The virtual control amount q required to make equation (0) match the desired characteristic of equation (41) is given by the following equation.

Q = k 1 · (1 + τ 2 s) / (1 + τ 1 s) · δsw (42) where k 1 = (af ² cf + ar ² cr) / (af ² cf + af ar cr) (43) τ 2 = Iz v / (af ² cf + ar ² cr) (44) Therefore, the calculation of the target control amount calculating means 213 is as follows (42)
Or (44) is discretized, and the calculated q is output as the target control amount signal qf.

The correction amount calculating means 233 is a feedback control amount for a behavior amount such that the deviation signal R0-R between the target yaw angular velocity signal R0 and the yaw angular velocity signal R gradually approaches zero. The correction amount signal qb is calculated and output. The algorithm of this operation is a control law with the linear state equation of equation (40) as the control target. That is,
Since Equation (40) is a linear equation of state, it is possible to apply linear control theory. In the case of the present embodiment, the correction amount signal qb is calculated based on the state equation shown by the following equation derived by applying the linear control theory.

Xc '= Acxc + Bc (R0-R) (45) qb = Ccxc + Dc (R0-R) (46) where Ac, Bc, Cc and Dc are constant matrices. In this case, the control law includes dynamic characteristics, and this control law is discretized into a recurrence formula. Further, the control law may be state feedback.

The control amount calculating means 243 includes a target control amount signal qf, which is a feedforward control amount calculated by the target control amount calculating means 213, and a correction amount calculating means
A correction amount signal qb, which is a feedback control amount calculated in 33, is added to obtain a linear control amount signal qf + qb.
Is output.

The nonlinear compensating means 303 calculates the vehicle speed signal v obtained by the vehicle speed sensor 110 and the behavior amount detecting means 13 from the linear control amount signal qf + qb obtained by the control amount calculating means.
1, the vehicle body slip angle signal β obtained from
Based on the yaw angular velocity signal R and the total driving force signal T, the front wheel actual steering angle δf as the steering control amount signal and the driving force distribution ratio λ as the drive control amount signal are calculated and output.

Next, the contents of the calculation in the nonlinear compensation means 303 will be described. Linear control amount signal qf + qb
And the front wheel actual steering angle signal δf and the driving force distribution ratio signal λ, the relationship between q and δf, λ shown in equation (39) is established. However, it is uncertain to solve for the front wheel actual steering angle δf and the driving force distribution ratio λ only from equation (39), and these signals, that is, the front wheel actual steering angle signal δf and the driving force distribution ratio signal λ must be uniquely determined. Can not. Therefore, here, the front wheel actual steering angle δf is calculated by the following algorithm.
And the driving force distribution ratio λ.

That is, first, increasing the driving force distribution ratio λ (approaching front wheel driving) contributes to suppressing the output of the yaw angular velocity, and decreasing the driving force distribution ratio (approaching rear wheel driving). Focuses on increasing the output of the yaw angular velocity, and calculates the driving force distribution ratio λ as shown in the following equation.

[0111] λ = -sgn (R) · K · | T | · (q f + q b) ... (47) However, K is a positive constant, sgn (R) has been meaning the sign of the R. In addition, the fact that the total driving force T is included in this equation means that the weight of control of the drive system is small during constant-speed running where the influence of the drive system on the turning characteristics is small, and the influence of the drive system on the turning characteristics is small. This means that the weight of control of the drive system is increased when the vehicle is running at a high acceleration. That is, T
Does not change much at the time of constant speed running when the value of
During acceleration running with a large value of λ, the control law uses a large change in λ to effectively use the driving force distribution ratio.

Then, λ in equation (47) is substituted into equation (39), and δ
The actual steering angle of the front wheels is obtained by solving for f. δf = ｛afcfq + (afcf−arcr) β−afcff | T | (1 + λ) · (β + afR / v) + arcrhr | T | (1-λ) · (β-arR / v ｝ / {Af cf + af cf hf | T | (1 + λ)} (48) where q = qf + qb

It is necessary to uniquely determine the front wheel actual steering angle δf and the driving force distribution ratio λ by such an algorithm.
Not only is the performance of the control for setting the behavior amount to the desired characteristic improved, but also the efficiency of the control is improved.

The steering control means comprises a front wheel steering actuator 41 for giving a steering angle corresponding to δf to the front wheels based on a front wheel actual steering angle signal δf as a steering control amount signal.

The drive control means variably controls the hydraulic pressure of the center differential hydraulic multiple disc clutch based on the drive force distribution ratio signal λ as the drive control amount signal.
Consists of

The operation and effect of this embodiment having the above-described configuration are as follows. First, the outputs of the vehicle speed sensor 110, the steering angle sensor 120, the vehicle body slip angle sensor 131, the yaw angular speed sensor 132, and the total driving force sensor 133 are input to a digital computer constituting the linear control amount calculating means 203 and the nonlinear compensating means 303. .

In the digital computer, first, a target yaw angular velocity R0, which is a target vehicle behavior quantity, is computed by a target behavior quantity computation means 223 according to a recurrence formula obtained by discretizing Expression (41).

In the target control amount calculating means 213, the driver can easily control the dynamic characteristics of the vehicle behavior (41).
A virtual control amount q required to change to the dynamic characteristics of the equation
Is calculated as a target control amount qf in accordance with a recurrence formula obtained by discretizing formulas (42) to (44).

Note that the target behavior amount follows the dynamic characteristic that makes it easy for the driver to steer. If there is no disturbance from the external environment such as fluctuation of vehicle specifications or cross wind disturbance, the behavior amount is the target behavior amount. Matches.

Next, in the correction amount calculating means 233,
Discretize Equations (45) and (46) for the correction amount signal qb required to make the deviation between the target behavior amount and the measured value of the behavior amount caused by fluctuations in vehicle specifications and disturbance from the external environment asymptotic to zero. Calculate according to the recurrence formula. With this correction amount signal, the dynamic characteristics of the vehicle behavior can be made to follow the target dynamic characteristics even when there are fluctuations in vehicle specifications and disturbance from the external environment.

Next, in the control amount calculating means 243,
The target control amount signal qf and the correction amount signal qb are added to output a linear control amount signal qf + qb.

Next, in the nonlinear compensating means 303,
A linear control amount signal qf + for obtaining a desired target behavior amount
The qb and q, (47), (48 ) in accordance with equation into a driving force distribution ratio signal λ as the front wheel steer SumiShin Nos δf and the drive control amount signal as a steering control amount signal. here
Thus, by including the total driving force T in the variable conversion of the equation (47), a control system for efficiently coordinating the steering system and the drive system is configured. That is, at the time of constant speed running in which the drive system has little effect on the turning characteristics, the value of T becomes small, so that the control of the drive system does not work and the hydraulic multi-plate clutch in the center differential is not operated unnecessarily. Further, during acceleration running in which the driving system has a large effect on the turning characteristics, the value of T becomes large, so that the control of the driving system is effectively used.

As described above, in this embodiment, the linear control amount calculating means 203 does not directly calculate the actual control parameters δf and λ, but calculates the linear control amount qf + qb. Is the steering control amount δ
f and the drive control amount λ.

For this reason, the control object viewed from the linear control amount calculating means 203, that is, the linear control amount qf + qb = q
Is input and the yaw rate R is output, (4
By linearly approximating the equation (0) and applying the linear control theory, it is possible to easily derive a control law for optimizing the characteristic of the yaw angular velocity.

Further, in this embodiment, in order to improve the characteristics of one behavior amount of the yaw angular velocity, two independent control amounts of the front wheel actual steering angle and the driving force distribution ratio are used. For this reason, one degree of freedom becomes redundant, but the nonlinear compensating means 303 makes effective use of this degree of freedom and efficiently distributes control to the steering system and the drive system according to the motion state of the vehicle. We provide an energy-saving control system that eliminates unnecessary movement.

In the above three embodiments, the control of the front and rear wheel distribution ratio of the driving force is used as the control amount of the driving system.
This can be easily extended to control of the front and rear wheel distribution ratio of the braking force. In this case, the total driving force T (<0) in the above embodiment.
Corresponds to the total braking force, and the driving force distribution ratio λ corresponds to the braking force distribution ratio. In the drive control means, the brake oil pressure of the front and rear wheels is variably controlled according to λ.

As described above, according to the present invention, the front wheel, the rear wheel, or the front and rear wheels are variably controlled as the steering system control, and the drive force distribution or the braking force distribution of the front and rear wheels is variably controlled as the drive system control. This is applied to an integrated control vehicle having a combination.

[Brief description of the drawings]

FIG. 1 is a diagram showing tire characteristics.

FIG. 2 is a block diagram illustrating a configuration according to a first exemplary embodiment.

FIG. 3 is a block diagram illustrating a configuration of a second embodiment.

FIG. 4 is a block diagram illustrating a configuration of a third embodiment.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B62D 101: 00 B62D 101: 00 105: 00 105: 00 111: 00 111: 00 113: 00 113: 00 137: 00 137 : 00 Examiner Toshiharu Yamagishi (56) References JP-A-4-339009 (JP, A) JP-A-4-126666 (JP, A) JP-A-5-262254 (JP, A) JP-A-5-58180 (JP, A) JP-A-5-270422 (JP, A) JP-A-4-87882 (JP, A) JP-A-4-46855 (JP, A) JP-A-4-133867 (JP, A) JP-A 64-103579 (JP, A) JP-A-5-170011 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 41/00 301 B62D 6/00 B62D 101: 00 B62D 105: 00 B62D 111: 00 B62D 113: 00 B62D 137: 00

Claims (2)

(57) [Claims] 1. A detecting means for detecting at least a steering wheel steering amount and a behavior amount representing a turning motion of a vehicle, and for causing the behavior amount to follow an appropriate characteristic according to the detected steering amount and the behavior amount. Linear control amount calculating means for performing a linear operation on the linear control amount based on a linear model representing the vehicle motion; anda non-linear conversion of the calculated linear control amount based on the detected behavior amount to obtain a steering control amount and a drive characteristic. Non-linear compensating means for outputting at least one of a drive control amount representing a braking characteristic and a braking control amount representing a braking characteristic; and a steering for generating an optimum steering angle on at least one of a front wheel and a rear wheel of the vehicle according to the steering control amount. Control means, and drive / brake control means for variably controlling distribution of at least one of the driving force and the braking force to the front and rear wheels in accordance with at least one of the drive control amount and the braking control amount. Integrated control apparatus for a vehicle according to claim Rukoto. 2. A target control amount calculating means for calculating a target control amount for achieving a target vehicle behavior amount based on the detected steering amount, and the detected steering amount. A target behavior amount calculating means for calculating a target vehicle behavior amount based on the amount; and a correction for causing the behavior amount to follow the target behavior amount according to the calculated target behavior amount and the detected behavior amount. Correction amount calculating means for linearly calculating the amount based on a linear model representing vehicle motion, and control amount calculating means for calculating the control amount by adding the target control amount and the correction amount calculated in the previous period. The integrated control device for a vehicle according to claim 1, wherein