JP2003159966A - Travelling control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control vehicular travelling movement in a most appropriate manner all the time for controlling the vehicular travelling movement by a plurality of behavior control means, regardless of changes in a vehicular state, particularly changes in properties of the behavior control means. <P>SOLUTION: A vehicular target longitudinal force Fxt, a target lateral force Fyt and a target yaw moment Mzt are computed (S100, 150), control response frequency characteristics G<SB>αi</SB>, G<SB>κi</SB>of a steering control means and a braking driving force control means are computed for each wheel (S200), weight W<SB>u</SB>in proportion to the inverse number of the characteristics G<SB>αi</SB>, G<SB>κi</SB>is computed (S250), a target slip rate κti and a target slip angle αti of each wheel are computed by distribution control employing an estimation function using the weight W<SB>u</SB>(S350), and the steering angle θwi of each wheel, a braking pressure Pi and an engine output torque are controlled (S900 to 1100) so that the target slip rate κti and the target slip angle αti are achieved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel control device, and more particularly to a vehicle travel control device having a plurality of behavior control means for controlling vehicle behavior in cooperation with each other.

[0002]

2. Description of the Related Art As one of running control devices for vehicles such as automobiles, left and right wheel torque difference control means for controlling the torque difference between the left and right wheels, as disclosed in Japanese Patent Laid-Open No. 6-335115, are provided. A steering angle control means for controlling the steering angle of at least one of the wheels, a means for calculating a left and right wheel torque difference target value mainly in a high frequency range for ensuring a stable running motion of the vehicle, and a stable running motion of the vehicle. A means for calculating a steering angle control target value mainly in a low frequency range for securing the steering angle control means for controlling the left and right wheel torque difference control means based on the left and right wheel torque difference target values, and a steering angle based on the steering angle control target value. Travel controllers configured to control a control means are known in the prior art.

Generally, in the behavior control of the vehicle by the left and right wheel torque difference control means, it is inevitable that the vehicle is accelerated and decelerated. According to the above-described traveling control device, in a situation where high response behavior control is required, the behavior of the vehicle is mainly controlled by the torque difference between the left and right wheels, and the behavior control does not need to be high response. In this case, since the behavior of the vehicle is controlled mainly by steering the wheels, it is possible to control the behavior of the vehicle with high responsiveness while suppressing unnecessary acceleration and deceleration of the vehicle.

[0004]

However, in the conventional traveling control device as described above, the control amount for ensuring the stable traveling motion of the vehicle is different from the left and right wheel torque difference control means and the steering angle control means. Since the mode of distribution is constant, when the situation of the vehicle changes, especially when the situation of the left and right wheel torque difference control means or the steering angle control means concerning the responsiveness of the traveling motion control of the vehicle changes, There is a problem that the running motion of the vehicle cannot always be optimally controlled.

The present invention mainly controls the left / right wheel torque difference control means based on the target value of the left / right wheel torque difference in the high frequency range to ensure a stable running motion of the vehicle to ensure a stable running motion of the vehicle. The present invention is mainly made in view of the above-mentioned problems in the conventional traveling control device configured to control the steering angle control means on the basis of the steering angle control target value in the low frequency range, and is a main feature of the present invention. The problem is to control the traveling motion of the vehicle by a plurality of behavior control means that cooperate with each other to control the behavior of the vehicle by different actions, and to control the behavior according to the characteristics of the plurality of behavior control means, particularly the control response frequency characteristics. By variably controlling the distribution of the running motion control target to the vehicle, the running motion of the vehicle is always maximized regardless of changes in the state of the vehicle, especially changes in the behavior control characteristics of the behavior control means. It is to control to.

[0006]

According to the present invention, the above-mentioned main problem is to provide a plurality of behavior control means for controlling the behavior of a vehicle in cooperation with each other by mutually different actions, and to stably drive the vehicle. Means for calculating the target behavior control amount of the entire vehicle for distributing the target behavior control amount of the entire vehicle to the plurality of behavior control means in accordance with the behavior control characteristics of the plurality of behavior control means. In a traveling control device for a vehicle having distribution control means for controlling the plurality of behavior control means based on the above, the distribution control means has means for sequentially detecting behavior control characteristics of the behavior control means. A vehicle travel control device (the structure of claim 1), or a plurality of behavior control means for controlling vehicle behavior in cooperation with each other by different actions, and the entire vehicle for stably traveling the vehicle. Means for calculating a target behavior control amount,
Distribution control means for distributing the target behavior control amount of the entire vehicle to the plurality of behavior control means according to the behavior control characteristics of the plurality of behavior control means, and controlling the plurality of behavior control means based on the distribution result. In the vehicle travel control device, the distribution control means may worsen the behavior of the vehicle depending on the distribution of the target behavior control amount of the entire vehicle according to the behavior control characteristics of the plurality of behavior control means. A vehicle traveling control device comprising: a determining unit that determines whether or not there is a vehicle; and a unit that changes the distribution of the target behavior control amount of the entire vehicle according to the determination result of the determining unit. (2) or a plurality of behavior control means for controlling the behavior of the vehicle in cooperation with each other by different actions, and a target behavior control amount of the entire vehicle for stably driving the vehicle. And a distribution control for distributing the target behavior control amount of the entire vehicle to the plurality of behavior control means according to the behavior control characteristics of the plurality of behavior control means and controlling the plurality of behavior control means based on the distribution result. And a distribution control means for distributing the target behavior control amount of the entire vehicle to the behavior control means having the highest priority in accordance with the behavior control characteristics of the plurality of behavior control means. And a means for allocating a difference between the target behavior control amount of the entire vehicle and the distribution amount to other behavior control means (vehicle construction control apparatus according to claim 6). ) Is achieved.

Further, according to the present invention, in order to effectively achieve the above-mentioned main problems, in the structure of claim 1 or 2, the plurality of behavior control means are independent of a steering operation by a driver. The steering control means for steering the wheels, and the braking / driving force control means capable of individually controlling the braking / driving force of each wheel regardless of the braking / driving operation by the driver are configured. ).

According to the present invention, in order to effectively achieve the above-mentioned main problem, in the structure of the above-mentioned claim 3, the distribution control means is one of the steering control means and the braking / driving force control means. The distribution weight of the target behavior control amount of the entire vehicle is set according to the behavior control characteristic, and the target behavior control amount of the entire vehicle is distributed to the steering control means and the braking / driving force control means according to the distribution weight. (Claim 4)
Configuration).

Further, according to the present invention, in order to effectively achieve the above-mentioned main problem, in the configuration of the above-mentioned claim 3, the distribution control means is one of the steering control means and the braking / driving force control means. A control response frequency is detected, and the target behavior control amount of the entire vehicle is frequency-separated based on the detected control response frequencies of the steering control means and the braking / driving force control means. Is distributed to the steering control means and the braking / driving force control means (configuration of claim 5).

Further, according to the present invention, in order to effectively achieve the above-mentioned main problem, in the structure of the above-mentioned claim 6, the plurality of behavior control means are the wheels regardless of the steering operation by the driver. Steering control means for steering the vehicle, and braking / driving force control means capable of individually controlling the braking / driving force of each wheel regardless of the braking / driving operation by the driver. It is configured to be a control means (configuration of claim 7).

[0011]

According to the constitution of the above-mentioned claim 1,
The behavior control characteristics of the plurality of behavior control means are sequentially detected, and the target behavior control amount of the entire vehicle is distributed to each behavior control means according to the detected behavior control characteristics. Since it is controlled, even if the behavior control characteristics of any of the behavior control means change, it is possible to change the distribution of the target behavior control amount of the entire vehicle to each behavior control means in response to the change. The running motion of the vehicle can always be optimally controlled regardless of changes in the behavior control characteristics of the behavior control means.

Further, according to the configuration of the above-mentioned claim 2, is there a possibility that the behavior of the vehicle may be deteriorated rather depending on the distribution of the target behavior control amount of the entire vehicle according to the behavior control characteristics of the plurality of behavior control means? Whether or not it is determined, and the distribution of the target behavior control amount of the entire vehicle is changed according to the determination result,
Depending on the distribution of the target behavior control amount of the entire vehicle according to the behavior control characteristics of the plurality of behavior control means, even if there is a situation in which the behavior of the vehicle deteriorates rather, the running motion of the vehicle is controlled without deteriorating the behavior of the vehicle. It can be controlled properly.

According to the sixth aspect of the present invention, the distribution amount of the target behavior control amount of the entire vehicle to the behavior control means of the highest priority is calculated according to the behavior control characteristics of the plurality of behavior control means, and the entire vehicle is calculated. Since the difference between the target behavior control amount and the distribution amount is distributed to the other behavior control means, the behavior control means of the highest priority controls the traveling motion of the vehicle preferentially, and the other behavior control means assists. It becomes possible to control the running motion of the vehicle.

According to the third aspect of the invention, the plurality of behavior control means includes steering control means and braking / driving force control means, and the steering control means steers the wheels independently of the steering operation by the driver. Since the braking / driving force control means individually controls the braking / driving force of each wheel regardless of the braking / driving operation by the driver, the target behavior of the entire vehicle according to the control characteristics of the steering control means and the braking / driving force control means. The control amount can be distributed to these control means, and the steering angle of the wheel and the braking / driving force can always be optimally controlled according to the distribution result.

According to the structure of claim 4, the distribution weight of the target behavior control amount of the entire vehicle is set according to the behavior control characteristics of the steering control means and the braking / driving force control means, and the set distribution weight is set. Accordingly, since the target behavior control amount of the entire vehicle is distributed to the steering control means and the braking / driving force control means, the target behavior control amount of the entire vehicle is set according to the behavior control characteristics of the steering control means and the braking / driving force control means. Can be optimally and easily distributed to the control means.

Further, according to the above configuration, the control response frequencies of the steering control means and the braking / driving force control means are detected, and based on the detected control response frequencies of the steering control means and the braking / driving force control means. Since the target behavior control amount of the entire vehicle is frequency separated, the target behavior control amount of the entire vehicle is distributed to the steering control means and the braking / driving force control means.
For the steering control means, the frequency-separated behavior control amount may be distributed to each wheel, and for the braking / driving force control means, the frequency-separated behavior control amount may be distributed to each wheel. Therefore, as described in detail later, the entire vehicle The target behavior control amount of the entire vehicle is distributed as compared with the case where the target behavior control amount is distributed to each wheel control amount of the steering control means and each wheel control amount of the braking / driving force control means without frequency separation. The calculation can be easily performed.

According to the above configuration, the plurality of behavior control means are steering control means for steering the wheels independently of the steering operation by the driver, and each of the wheels is independent of the braking / driving operation by the driver. When the braking / driving force control means is capable of individually controlling the braking / driving force, the behavior control means having the highest priority is the steering control means, and therefore the behavior control means having the highest priority is the braking / driving force control means. In comparison, it is possible to reduce the risk that the vehicle is unnecessarily accelerated or decelerated due to the traveling control of the vehicle.

[0018]

According to a preferred embodiment of the present invention, in the above-mentioned constitution of claim 1 or 2 or 6, the means for calculating the target behavior control amount of the entire vehicle is the vehicle driving of the driver. It is configured to calculate a target behavior control amount of the entire vehicle based on a deviation between a target internal state amount of the vehicle corresponding to a target behavior of the vehicle based on an operation amount and an actual internal state amount of the vehicle based on a running state of the vehicle. (Preferred embodiment 1).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 1, the target internal state quantity of the vehicle is a target longitudinal force of the vehicle, a target lateral force, and a target yaw moment, The actual internal state quantity of is configured to be the actual longitudinal force, lateral force, and yaw moment of the vehicle (preferred aspect 2).

According to another preferred embodiment of the present invention, in the above-mentioned constitution of claim 1 or 2 or 6, the distribution control means is a target of the whole vehicle according to the behavior control characteristics of the plurality of behavior control means. By distributing the behavior control amount to the plurality of behavior control means, the target behavior control amount of each behavior control means is calculated, and the plurality of behavior control means is controlled based on the target behavior control amount (Preferred Mode 3 ).

According to another preferred aspect of the present invention, in the structure of claim 1 or 2 or 6, the behavior control characteristic is a control response frequency characteristic of each behavior control means ( Preferred embodiment 4).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 4, the distribution control means has a target of the entire vehicle in proportion to the inverse characteristic of the control response frequency characteristic of each behavior control means. The behavior control amount is configured to be distributed to a plurality of behavior control means (preferred aspect 5).

According to another preferred aspect of the present invention, in the structure of claim 1, the means for sequentially detecting the behavior control characteristics of the behavior control means is based on the inputs and outputs of the plurality of behavior control means. The behavior control characteristic of the behavior control means is configured to be sequentially detected (preferred aspect 6).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 6, the means for sequentially detecting the behavior control characteristics of the behavior control means is capable of detecting the behavior control characteristics of any one of the behavior control means. When it cannot be detected, the behavior control means is configured to maintain the previous behavior control characteristics (preferred mode 7).

According to another preferred aspect of the present invention, in the structure of claim 2, the plurality of behavior control means include steering control means for steering the wheels independently of a steering operation by a driver, Including a braking / driving force control means capable of individually controlling the braking / driving force of each wheel regardless of the braking / driving operation by the driver, the judging means judges whether or not the tack-in is occurring, and the target behavior of the entire vehicle. The means for changing the distribution of the control amount is configured to increase the distribution to the steering control means and decrease the distribution to the braking / driving force control means when the determination means determines that the tack-in is occurring (Preferred Aspect 8). ).

According to another preferred aspect of the present invention, in the structure of claim 2, the plurality of behavior control means include steering control means for steering the wheels independently of a steering operation by a driver, A braking / driving force control means capable of individually controlling the braking / driving force of each wheel regardless of the braking / driving operation by the driver, and the determining means determines whether or not the vehicle is in a turning acceleration state, and determines the entire vehicle. The means for changing the distribution of the target behavior control amount is configured to reduce the distribution to the steering control means and increase the distribution to the braking / driving force control means when the determination means determines that the vehicle is in the turning acceleration state. (Preferred embodiment 9).

According to another preferred aspect of the present invention, in the structure of claim 4, the distribution control means detects the control response frequency characteristic of the steering control means and the braking / driving force control means, and the control response. It is configured to set the distribution weight to a value proportional to the inverse characteristic of the frequency characteristic (Preferred Embodiment 1
0).

According to another preferred aspect of the present invention, in the configuration of the preferred aspect 10, the distribution control means detects the control response frequency characteristics of the steering control means and the braking / driving force control means for each wheel. , A value proportional to the inverse characteristic of the control response frequency characteristic is set as the distribution weight (preferred aspect 11).

According to another preferred aspect of the present invention, in the structure of claim 5, the distribution control means controls the target behavior of the steering control means on the basis of the target behavior control amount of the entire vehicle separated by frequency. And the target behavior control amount of the braking / driving force control means are calculated (preferred aspect 1
2).

According to another preferred aspect of the present invention, in the structure of claim 7, the distribution control means determines whether or not the highest priority order needs to be changed based on the running state of the vehicle. It is configured to change the highest priority behavior control means to the braking / driving force control means when it is determined that the highest priority change is necessary (preferred aspect 13).

[0031]

[Summary of distribution control in the present invention] Next, in the case where the behavior control means is the steering control means and the braking / driving force control means, the target longitudinal force of the vehicle, the target lateral force, as the target behavior control amount of the entire vehicle, An outline of distributing the target yaw moment to each control means and calculating the target slip angle and the target slip amount as the control target amount for each wheel will be described.

[1] Steering control means and braking / driving force control means
Allocation to Modification of vehicle longitudinal force Fx, lateral force Fy, yaw moment Mz
The error of the quantity is E, and the left front wheel, right front wheel, left rear wheel, and right rear wheel
Slip angle α₁~ Α_FourAnd slip ratio κ₁~ Κ_FourBe u,
Change in slip angle of each wheel δα₁~ Δα_FourAnd slip
Rate change δκ ₁~ Δκ_FourBe δu, and the correction amount error E
The weight for W_EThe slip angle and slip of each wheel.
The weight for the change rate δu of the_δuAnd u + δu
The weight for W_uThe evaluation function L is expressed as
Let's do it.

[0033] _{^{L = E T W E E +}} δu T W δu δu + (u + δu) T W u (u + δu) ...... (1) Note that in the above-mentioned formula 1, the correction amount of the error E, the slip angle and the slip ratio of each wheel The variable δu, the slip angle of each wheel, and the slip ratio u are expressed by the following equations 2 to 4, respectively.

E = Δ-dF (2) δu = [δκ ₁・ ・ ・ δκ ₄ δα ₁・ ・ ・ δα ₄ ] ^T・ ・ ・ (3) u = [κ ₁・ ・ ・ κ ₄ α ₁・ ・ ・ α ₄ ] ^T ...... (4)

Δ in the above equation 2 is the longitudinal force Fx of the vehicle,
It is a target correction amount of the lateral force Fy and the yaw moment Mz. The target longitudinal force of the vehicle is Fxt, the target lateral force is Fyt, and the target yaw moment is Mzt.

[Equation 1]

The dF in the above formula 2 is obtained by linearly approximating the correction amounts of the longitudinal force Fx, lateral force Fy, and yaw moment Mz of the vehicle due to the slip angle and slip ratio change amount δu of each wheel near the operating time point. It is a value obtained by the following equation and is represented by the following equations 6 and 7. In addition, the above formula 5
The longitudinal force Fx, lateral force Fy, yaw moment Mz and Jacobian J of the vehicle used in No. 7 are estimated by the tire model described later.

[0037]

[Equation 2]

[Equation 3]

When the control target is distributed to the steering control means and the braking / driving force control means to obtain the target slip angle and the target slip ratio of each wheel, the evaluation function expressed by the above equation 1 is repeatedly calculated by the steepest descent method. A target correction amount δut of the slip angle and the slip ratio that minimizes L is calculated, and the correction amount δut is added to the current value u to obtain the target slip angles αt _{1 to} αt ₄ and the target slip ratio κt ₁ of each wheel. ~ Κt ₄ is calculated.

The target correction amount δut is calculated as follows. That is, the following expression 8 is established from the above expression 1, and the evaluation function L
Since ∂L / ∂δu is 0 when is minimum, the following equation 9 is established, and therefore the target correction amount δut is represented by the following equation 10.

[Equation 4] _{(W δu + W u + J} T W E J) δut + (W u u-J T W E Δ) = 0 ...... (9) δut = (W δu + W u + J T W E J) -1 (J T W E Δ-W _u u) (10)

In this case, the behavior control characteristics of the steering control means and the braking / driving force control means are sequentially detected for each wheel, and the weight W _u is variably set based on the detection result, whereby the steering control means and the braking / driving force are set. Optimal distribution of the target behavior control amount (target longitudinal force Fxt, target lateral force Fyt, target yaw moment Mzt) of the entire vehicle to the steering control means and braking / driving force control means for each wheel according to the behavior control characteristics of the control means. Turn into.

[2] Allocation to braking / driving force control means Front / rear force Fx, lateral force Fy of the vehicle relating to braking / driving force control means,
The error of the correction amount of the yaw moment Mz is defined as E _κ, and the slip ratios κ ₁ to κ ₄ of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel are expressed as κ.
And the amount of change in slip ratio of each wheel δκ _{1 to} δκ ₄ is
And then, a weight for error E _kappa of correction amount and W _Ikappa, weights for variation Derutakappa slip ratio of each wheel and W _Derutakappa, and as the evaluation function L _kappa Equation 11 below the weight for κ + δκ as W _kappa To do. ^{_{L κ = E κ T W Eκ}} Eκ + δκ T W δκ δκ + (κ + δκ) T W κ (κ + δκ) ...... (11)

In the above equation 11, the correction amount error E _κ , the slip rate variation δκ of each wheel, and the slip rate κ of each wheel are represented by the following equations 12 to 14, respectively. E _κ = Δ _κ −dF _κ (12) δ _κ = [δ _{κ 1} … δ κ ₄ ] ^T …… (13) κ = [κ ₁ …… κ ₄ ] ^T …… (14)

Δ _{κ in the} above equation 12 is a target correction amount of the vehicle longitudinal force Fx, lateral force Fy, and yaw moment Mz relating to the braking / driving force control means, and is the target longitudinal force of the vehicle relating to the braking / driving force control means. Fxt _κ , the target lateral force is Fyt _κ ,
The target yaw moment is represented by Mzt _{κ and} is expressed by the following equation 15.

[Equation 5]

Further, dF _{κ in the} above equation 12 is obtained by linearly approximating the correction amounts of the longitudinal force Fx, lateral force Fy and yaw moment Mz of the vehicle due to the change amount δκ of the slip ratio of each wheel in the vicinity of the operating time point. The values are represented by the following equations 16 and 17. The above equations 15 to 17
The longitudinal force Fx, lateral force Fy, yaw moment Mz and Jacobian J _κ of the vehicle used in the vehicle are estimated by a tire model described later.

[0045]

[Equation 6]

[Equation 7]

When the control target is distributed to the braking / driving force control means to obtain the target slip ratio of each wheel, the slip ratio that minimizes the evaluation function L _κ expressed by the above equation 11 is obtained by iterative calculation by the steepest descent method. Target correction amount δκt
Is calculated, and the correction amount Δκt is added to the current value κ to calculate the target slip ratios κt _{1 to} κt ₄ of each wheel.

The target correction amount δκt is calculated as follows. That is, from the above equation 11, the following equation 18 is established, and when the evaluation function L _κ is the minimum, ∂L _κ / ∂δκ is 0. Therefore, the following equation 19 is established, and therefore the target correction amount δκt
Is represented by the following equation 20.

[0048]

[Equation 8] _{(W δκ + W uκ + J} κ T W Eκ J κ) δκt + (W uκ κ-J κ T W Eκ Δ κ) = 0 ...... (19) δκt = (W δκ + W uκ + J κ T W Eκ J κ) - ¹ (J _κ ^T W _{E κ} Δ _κ- W _u κ κ) (20)

In this case, the behavior control characteristic of the braking / driving force control means is sequentially detected for each wheel, and the weight W _{u κ} is variably set based on the detection result, so that the behavior control characteristic of the braking / driving force control means is changed. Target behavior control amount of the braking / driving force control means for each wheel (target longitudinal force Fxt _κ , target lateral force F
yt _κ and target yaw moment Mzt _κ ) are optimized.

[3] Allocation to steering control means Vehicle longitudinal force Fx, lateral force Fy, yaw related to steering control means
The error of the correction amount of the moment Mz is E_αAnd left front wheel, right
Front wheel, left rear wheel, right rear wheel slip ratio α₁~ Α_FourIs α,
Change in slip ratio of each wheel δα₁~ Δα_FourBe δα,
Correction amount error E _αThe weight for W_EαAnd for each wheel
The weight for the change rate δα of the slip ratio is W_δαAnd α
The weight for + δα is W_αAs the evaluation function L_αThe below
As shown in Expression 21, L_α= E_α ^TW_EαEα + δα^TW_δαδα + (α + δα)^TW_α(Α + δα)                                                   …… (21)

In the above equation 21, the correction amount error E _α , the slip rate variation δα of each wheel, and the slip rate α of each wheel are represented by the following equations 22 to 24, respectively. _{E α = Δ α -dF α ......} (22) δα = [δα 1 ... δα 4] T ...... (23) α = [α 1 ... α 4] T ...... (24)

Δ _{α in the} above equation 22 is the vehicle longitudinal force Fx, lateral force Fy, and yaw moment Mz related to the steering control means.
The target correction amount of the steering control means is represented by Fxt _α , the target lateral force is Fyt _α , and the target yaw moment is Mzt _α .

[Equation 9]

Further, dF _{α in the} above equation 22 is obtained by linearly approximating the correction amounts of the vehicle longitudinal force Fx, lateral force Fy, and yaw moment Mz due to the slip rate change amount δα of each wheel in the vicinity of the operating time point. Is a value represented by the following equations 26 and 27. The above equations 25 to 27
The longitudinal force Fx, lateral force Fy, yaw moment Mz and Jacobian J _α of the vehicle used in the vehicle are estimated by the tire model described later.

[0054]

[Equation 10]

[Equation 11]

The control target is distributed to the steering control means and each wheel is distributed.
The steepest descent method is used to obtain the target slip ratio of
The evaluation function expressed by the above equation 21 by the iterative calculation
Number L _αThe target correction amount δαt of the slip ratio that minimizes
And the correction amount δαt is added to the current value α
From the target slip ratio αt of each wheel₁~ Αt_FourIs calculated.

The target correction amount δαt is calculated as follows. That is, the following expression 28 is established from the above expression 21, and when the evaluation function L _α is the minimum, ∂L _α / ∂δα is 0, so the following expression 29 is established, and therefore the target correction amount δαt
Is represented by the following Equation 30.

[0057]

[Equation 12] _{(W δα + W uα + J} α T W Eα J α) δα + (W uα α-J α T W Eα Δ α) = 0 ...... (29) δα = (W δα + W uα + J α T W Eα J α) - ^{_{1 (J α T W Eα Δ}} α -W uα α) ...... (30)

In this case, the behavior control characteristic of the steering control means is sequentially detected for each wheel, and the weight W is determined based on the detection result.
_By variably setting _uα , the _distribution of the target behavior control amount (target longitudinal force Fxt _α , target lateral force Fyt _α , target yaw moment Mzt _α ) of the steering control means to each wheel according to the behavior control characteristics of the steering control means To optimize.

[4] Tire model According to the brush tire model, κi is the tire slip ratio, Fzi is the tire ground load, _Kκ0 is the driving stiffness normalized by the load, and K
Let _α0 be the cornering power normalized by the load, and μ
Is the maximum friction coefficient of the road surface, the driving stiffness K _κ and the cornering power K _α are expressed by the following equations 33 and 34, respectively. Further, assuming that the angle formed by the road reaction force of the tire with respect to the front-rear direction of the tire is θfi and λ and ξ are values represented by the following equations 35 and 36, cos θfi and sin θfi are represented by the following equations 31 and 32, respectively. Is represented.

[0060]

[Equation 13]

The tire longitudinal force Fxi and lateral force Fyi are expressed by the following equations 37 and 38 when ξ ≧ 0, and by the following equations 39 and 40 when ξ ≦ 0.

[Equation 14]

[0062] [5] The longitudinal acceleration of the ground contact load vehicle as Gx, lateral acceleration of the vehicle as Gy, the sprung mass of the vehicle and M _b, the center height H _c of the vehicle, the roll center height of the vehicle H _φ , the pitch center height of the vehicle is H _θ , the wheel base of the vehicle is L, the tread of the front wheel of the vehicle is Trf, the tread of the rear wheel of the vehicle is Trr, and the front roll rigidity of the vehicle is K _φf age,
When the rear roll rigidity of the vehicle is K _φr and the pitch rigidity of the vehicle is K _θ , the vehicle body pitch angle θ _h and the roll φ _h are expressed by the following equations 41 and 42, respectively. The left front wheel, the right front wheel, and the left wheel Ground load F _xi (i = fl, fr, r for rear and right rear wheels)
l, rr) is calculated by the following equation 43.

[0063]

[Equation 15]

[6] The relationship T (Δi) between the tire longitudinal force Fxi and lateral force Fyi and the vehicle longitudinal force Fx, lateral force Fy, and yaw moment Mz is calculated as the tire longitudinal force Fxi and tire lateral force Fyi of each wheel. Assuming that the coefficients T (i) and L (i) are converted into the longitudinal force Fx and the lateral force Fy of the vehicle, and the coefficients T (i) and L (i) are represented by the following equations 46 and 47, the longitudinal force Fx and the lateral force Fy of the vehicle are expressed. Is expressed by the following equation 44, and the yaw moment Mz of the vehicle is expressed by the following equation 45.

[0065]

[Equation 16]

[0066]

[0067]

DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail with reference to the accompanying drawings, in which some preferred embodiments are described.

First Embodiment FIG. 1 is a schematic configuration diagram showing a first embodiment of a vehicle travel control device according to the present invention. In FIG. 1, reference numeral 10 denotes an engine mounted on a vehicle 12 as a drive source. The driving force of the engine 10 is transmitted to an output shaft 18 via a torque converter 14 and a transmission 16, and the output shaft 18 The driving force is transmitted to the front wheel propeller shaft 22 and the rear wheel propeller shaft 24 by the center differential 20. The output of the engine 10 is controlled by the engine control unit 26 according to the amount of depression of an accelerator pedal which is not shown in FIG.
Controlled by.

The driving force of the front wheel propeller shaft 22 is transmitted to the left front wheel axle 32L and the right front wheel axle 32R by the front wheel differential 30, whereby the left and right front wheels 3 are transmitted.
4FL and 34FR are rotationally driven. Similarly, the driving force of the rear wheel propeller shaft 24 is the rear wheel differential 36.
Is transmitted to the left rear wheel axle 38L and the right rear wheel axle 38R, whereby the left and right rear wheels 40RL and 40RR are rotationally driven.

Thus, the torque converter 14, the transmission 16, the center differential 20, the front wheel differential 30, the rear wheel differential 3
6 and the like make up the drive system of the vehicle. In particular, the drive system of the illustrated embodiment includes left and right front wheels 34FL, 34FR and left and right rear wheels 40FL and 34FR.
The drive torque of the engine 10 is distributed to the RL and 40RR at a constant distribution ratio, and the engine control device 26 controls the engine 1 to
The drive torque transmitted from 0 to each wheel is generally controlled.

The braking force of the left and right front wheels 34FL, 34FR and the left and right rear wheels 40RL, 40RR is the hydraulic circuit 44 of the braking device 42.
Corresponding wheel cylinders 46FL, 46FR, 46
It is controlled by controlling the braking pressures of RL and 46RR. Although not shown in the figure, the hydraulic circuit 44 includes a reservoir, an oil pump, various valve devices, etc., and the braking pressure of each wheel cylinder is normally driven according to the pedaling force applied to the brake pedal 47 by the driver. It is controlled by the cylinder 48 and, if necessary, is individually controlled by the electronic control unit 50 for traveling control as described in detail later.

Further, as shown in FIG. 1, the left and right front wheels 34FL and 34FR are steered by the front wheel steering device 52. In the illustrated embodiment, the front wheel steering device 52 is a hydraulic power steering device 56 that is driven in response to a steering operation of a steering wheel 54 by a driver.
The left and right front wheels 34FL and 34FR are steered by the power steering device 56 via tie rods 58L and 58R.

Tie rods 58L and 58R are provided with actuators 60L and 60R for variably controlling their effective lengths, respectively.
0R is controlled by the steering angle control device 62, whereby the steering angles of the left and right front wheels 34FL and 34FR are controlled independently of each other and independently of the rear wheels 40RL and 40RR.

Similarly, the left and right rear wheels 40RL and 40RR are steered by the rear wheel steering device 64. Rear wheel steering device 6
4 has a hydraulic power steering device 66 driven in response to a steering operation of a steering wheel 54 by a driver or a vehicle speed, and 40RL and 40RR of the left and right rear wheels are connected to tie rods 68L and 68R by the power steering device 66. Steered through.

The tie rods 68L and 68R are provided with actuators 70L and 70R for variably controlling their effective lengths, respectively.
6 and the actuators 70L and 70R are steering angle control devices 62.
The left and right rear wheels 40RL and 40 are controlled by
The steering angles of the RRs are independent of each other and the front wheels 34FL and 34FR
It is controlled independently of.

As can be understood from the above description, the front wheel steering device 52, the rear wheel steering device 64, and the steering angle control device 62 are steering control means capable of individually controlling the steering angles of the wheels 34FL, 34FR, 40RL, 40RR. The engine 10, the engine control device 26, the braking device 42, and the electronic control device 50 cooperate with each other to form a braking / driving force control means capable of individually controlling the braking / driving force of each wheel. The electronic control unit 50 functions as a control unit that controls the steering control unit and the braking / driving force control unit.

In the electronic control unit 50, a signal indicating the vehicle speed Vx from the vehicle speed sensor 72, signals indicating the longitudinal acceleration Gx and lateral acceleration Gy of the vehicle 12 from the longitudinal acceleration sensor 74 and the lateral acceleration sensor 76, respectively, and a signal indicating the vehicle speed from the yaw rate sensor 78. A signal indicating the yaw rate γ, a signal indicating the pedaling force Fb (the amount of braking control operation by the driver) on the brake pedal 47 from the pedaling force sensor 80, and a wheel speed sensor 82i (i = f).
l, fr, rl, rr), a signal indicating the wheel speed Vwi of the left and right front wheels and the left and right rear wheels, and a pressure sensor 84i (i = fl, fr, rl, r)
A signal indicating the braking pressure Pi of the left and right front wheels and the left and right rear wheels, that is, the pressure in the wheel cylinders 46FL, 46FR, 46RR, and 46RL is input from r). The braking control operation amount by the driver is the pressure in the master cylinder 48 or the brake pedal 47.
It may be detected by the stepping stroke.

On the other hand, in the engine control device 26, a signal indicating the engine speed Ne from the engine speed sensor 86, a signal indicating the throttle opening Ta (driving force control operation amount by the driver) from the throttle opening sensor 88, and a shift position. Signals indicating the shift position Ps of the transmission 16 are input from the (SP) sensor 90, and these signals are also input from the engine control device 26 to the electronic control device 50. The driving force control operation amount by the driver may be detected by the depression stroke of the accelerator pedal.

Furthermore, the steering angle control device 62 includes a steering angle sensor 9
The signal indicating the steering angle θ (the steering control operation amount by the driver) as the rotation angle of the steering shaft connected to the steering wheel 54 from 2 and the steering angle sensor 94i (i
= Fl, fr, rl, rr), the steering angle θ of the left and right front wheels and the left and right rear wheels
Signals indicating wi are input, and these signals are also input to the electronic control unit 50 from the steering angle control unit 62.

The longitudinal acceleration sensor 74 detects the longitudinal acceleration with the acceleration direction of the vehicle being positive, and the lateral acceleration sensor 76,
The yaw rate sensor 78 and the steering angle sensor 92 detect lateral acceleration and the like with the left turning direction of the vehicle being positive. Further, the engine control device 26, the electronic control device 50, and the steering angle control device 62 are actually, for example, CPU, ROM, R, respectively.
It may be composed of an AM, a microcomputer including an input / output device, and a driving circuit.

As will be described in detail later, the running control electronic control unit 50 first follows the routines shown in FIGS. 3 to 6 to determine the target yaw rate γt of the vehicle as the target motion state quantity of the vehicle based on the vehicle speed Vx and the like. Target lateral acceleration Gy
t, the target longitudinal acceleration Gxt of the vehicle is calculated, and based on these, the target longitudinal acceleration G of the vehicle is set as the target internal state quantity of the vehicle.
Target longitudinal force Fxt, target lateral acceleration Gyt corresponding to xt
The target lateral force Fyt of the vehicle corresponding to the above and the target yaw moment Mzt of the vehicle corresponding to the target yaw rate γt are calculated.

Further, the traveling control electronic control unit 50 calculates the control response frequency characteristics G _αi and G _κi of the steering control means and the braking / driving force control means, as will be described later, and the value proportional to the reciprocal thereof is given by the above equation (10). The target correction amount δκti of the slip ratio of each wheel and the target correction amount δαti (i = fl, fr, rl, rr) of each wheel by the distribution control are calculated as the weight W _u in the above equation, and based on these, the above equation 69 is calculated. And 70, the target slip ratio κti and the target slip angle αti (i
= Fl, fr, rl, rr) is calculated.

The traveling control electronic control unit 50 then calculates the target braking pressure Pti for each wheel and the target drive torque Tet for the engine based on the target slip ratio κti, and the braking pressure Pi for each wheel becomes the target braking pressure Pti. By controlling the braking device 42 and the engine 10 so that the driving torque of the engine becomes the target driving torque Tet, the slip ratio κi of each wheel is controlled.
To the target slip ratio κti, and the target slip angle α
The target steering angle θwti of each wheel is calculated based on ti, and the front wheel steering device 5 is adjusted so that the steering angle θwi of each wheel becomes the target steering angle θwti.
2 and the rear wheel steering device 64 are controlled to control the slip angle αi of each wheel to the target slip angle αti.

Next, the vehicle traveling control routine in the first embodiment will be described with reference to the flow charts shown in FIGS. The control by the main routine of the flowchart shown in FIG. 3 is started by closing an ignition switch (not shown) and is repeatedly executed at predetermined time intervals.

First, in step 50, the vehicle speed sensor 7
A signal or the like indicating the vehicle speed Vx detected by 2 is read, and in step 100, the target yaw rate γ of the vehicle is set as the target motion state quantity of the vehicle based on the vehicle speed Vx and the like.
t, target lateral acceleration of vehicle Gyt, target longitudinal acceleration of vehicle Gx
t is calculated.

For example, the target yaw rate γt is calculated according to the following equation 48 with N as the steering gear ratio, L as the wheel base of the vehicle, Kh as the stability factor, and H (s) as the steering-yaw rate transient transfer function.
The target lateral acceleration Gyt is calculated by the following equation 49 using the yaw rate-lateral acceleration transient transfer function as G (s), and the target longitudinal acceleration Gxt is the engine speed Ne, the throttle opening Ta,
The gear ratio Rd of the drive system based on the shift position Ps of the transmission 16 and the pedaling force Fb on the brake pedal
Is used as a variable and is calculated according to the following expression 50 by a function F (Ne, Ta, Rd, Fb) for calculating the target longitudinal acceleration of the vehicle.

Γt = θ · Vx / {N · L (1 + Kh · Vx ² )} H (s) (48) Gyt = γt · Vx · G (s) (49) Gxt = F (Ne, Ta, Rd, Fb) (50)

In step 150, as the target internal state quantity of the vehicle, the target longitudinal force Fxt of the vehicle corresponding to the target longitudinal acceleration Gxt of the vehicle, the target lateral force Fyt of the vehicle corresponding to the target lateral acceleration Gyt, and the target yaw rate γt are set. The target yaw moment Mzt of the corresponding vehicle is calculated.

In particular, the target longitudinal force Fxt and the target lateral force F of the vehicle are
yt is calculated according to the following equations 51 and 52 with the mass of the vehicle as Mv, and the target yaw moment Mzt is calculated according to the following equation 53 with the yaw moment of inertia of the vehicle as Iy and the differential value of the target yaw rate γt of the vehicle as γtd. To be done. Fxt = Mv · Gxt …… (51) Fyt = Mv · Gyt …… (52) Mzt = Iy · γtd …… (53)

In step 200, the steering angle control device 6
The control signal (steering control input) output from the actuator 2 to the actuators 60L, 60R, 70L, 70R and the steering angle sensor 94i
Based on the steering angle θwi (steering control output) of each wheel detected by, the steering control means expressed by the following formula 54, where T _ααi is a coefficient, T _αi is a time constant, and s is a Laplace operator Control response frequency characteristic G _αi (i = fl, fr, rl, r
r) is calculated, and the engine 10 is controlled by the electronic control unit 50 via the braking unit 42 and the engine control unit 26.
To a wheel acceleration Vwdi (i = fl, fr, r) obtained as a differential value of the control signal (steering control input) output to the wheel speed sensor 82i and the wheel speed Vwi of each wheel detected by the wheel speed sensor 82i.
l, rr) (steering control output), T _{o κi} is a coefficient, T _κi is a time constant, and s is a Laplace operator. G _κi (i = fl, fr, rl, rr) is calculated. G _αi = 1 / {T _oαi (1 + T _αi s)} (54) G _κi = T _oκi (1 + T _αi s)} (55)

At the start of control, the control response frequency characteristic G _αi of the steering control means and the control response frequency characteristic G _κi of the braking / driving force control means are set to preset initial values, and the control response frequency characteristic G of the steering control means is set. _{When αi} or the control response frequency characteristic G _κi of the braking / driving force control means cannot be calculated, the characteristic G _αi or G _κi is set to the previous value.

In step 250, Ks and Kb are used as positive constant coefficients which have been experimentally obtained in advance, and the weight W _{u in} the above equation 10 for the distribution control of the control target is set.
Is the control response frequency characteristic G as shown in the following equation 56.
It is set to a value proportional to the reciprocal of αi and Gκi. W _u = diag (Ks / G _αfl ... Ks / G _αrr Kb / G _κfl ... Kb / G _κrr ) (56)

In step 300, the target slip ratio κti and the target slip angle αti (i = fl, fr, r) of each wheel by the distribution control according to the routine shown in FIG. 4 which will be described later.
l, rr) is calculated, and in step 900, the target steering angle θwt of each wheel is calculated according to the routine shown in FIG.
i (i = fl, fr, rl, rr) is calculated.

In step 1000, the target braking pressure Pti (i) for each wheel is calculated according to the routine shown in FIG.
= Fl, fr, rl, rr) and the target drive torque Tet of the engine 10 are calculated, and in step 1100, the steering wheel 52 for the front wheels and the rear wheels for the rear wheels are adjusted so that the steering angle θwi of each wheel becomes the target steering angle θwti. The steering device 64 for steering is the steering angle control device 62.
The braking device 42 is controlled so that the wheel cylinder pressure Pi of each wheel becomes the target braking pressure Pti, and the engine control device 26 controls the engine 10 so that the driving torque Te of the engine 10 becomes the target driving torque Tet. It

Target slip ratio κ of each wheel shown in FIG.
Step 31 of ti and target slip angle αti calculation routine
At 0, the slip rate κi and the slip angle αi (i = fl, fr, rl, rr) of each wheel are calculated based on the wheel speed Vwi of each wheel and the like in a manner known in the art. It

For example, the slip angle β of the vehicle is calculated according to the following expression 57, and the advancing direction angle αwi (i = fl, fr, rl, rr) of the ground contact point of each wheel is calculated according to the following expressions 58 to 61, The slip angle αi of each wheel is calculated according to the following formula 62.
Is calculated as the sum of the steering angle θwi and the advancing direction angle αwi of the ground contact point. As shown in Fig. 12 for the left front wheel,
The traveling direction angle αwi of the ground contact point is the ground contact point Pzi (i = f) of each wheel.
(l, fr, rl, rr) is the angle formed by the direction of travel with respect to the longitudinal direction of the vehicle.

[0097] β = ∫ (Gy / Vx−γ) dt (57) αwfl = (β ・ Vx + Lf ・ γ) / (Vx-Trf ・ γ / 2) ...... (58) αwfr = (β ・ Vx + Lf ・ γ) / (Vx + Trf ・ γ / 2) ...... (59) αwrl = (β ・ Vx-Lr ・ γ) / (Vx-Trr ・ γ / 2) ...... (60) αwrr = (β · Vx−Lr · γ) / (Vx + Trr · γ / 2) (61) αi = θwi + αwi (62)

Further, the longitudinal velocity Vwxi (i = fl, fr, rl, rr) of the ground contact point of each wheel is calculated according to the following equations 63 to 66, and the moving speed Vtwi of each wheel in the rolling direction is calculated according to the following equation 67. (I = fl, fr, rl, rr) is calculated, and the slip ratio κi of each wheel is calculated according to the following equation 68.

[0099] Vwxfl = Vx + Trf · γ / 2 (63) Vwxfr = Vx-Trf · γ / 2 (64) Vwxrl = Vx + Trr · γ / 2 (65) Vwxrr = Vx-Trr · γ / 2 (66) Vtwi = Vwxi (cos θwi-tanαi · sin θwi) (67) κi = 1-Vrwi / Vtwi (68)

In step 320, the above equations 41 to 4 are
Ground contact load of each wheel Fzi (i = fl, fr, rl, r
r) is calculated, and in step 330, the above equation 37 is calculated.
And 38 or the above-mentioned formulas 39 and 40, the longitudinal force Fxi and lateral force Fyi (i = fl, fr, rl, rr) of each wheel are calculated.

In step 340, the above equations 44-4 are used.
7, the vehicle longitudinal force Fx, lateral force Fy, and yaw moment Mz are calculated. In step 350, the vehicle longitudinal force Fx, lateral force Fy, and yaw moment Mz are calculated in accordance with the above equation 5.
The target correction amount Δ of is calculated.

In step 360, the longitudinal force F of the vehicle
By partially differentiating x, lateral force Fy, and yaw moment Mz with the slip ratio κi and slip angle αi of each wheel, the Jacobian J represented by the above equation 7 is calculated, and in step 370, the above equation 10 is obtained. Target correction amount δ
u, that is, the target correction amount δκti of the slip ratio of each wheel and the target correction amount δαti of the slip angle (i = fl, fr, rl, rr) are calculated. In this case, the weight W _{δu in the} above equation 10
And W _E are set to constants experimentally obtained in advance.

In step 380, the target slip rate κti of each wheel is calculated as the sum of the current slip rate κi and the target correction amount Δκti of the slip rate according to the following equation 69, and the target slip angle of each wheel is calculated. αti is calculated as the sum of the current slip angle αi and the target correction amount Δαti of the slip angle according to the following expression 70, and then the process proceeds to step 900. κti = κi ＋ δκti …… (69) αti ＝ αi ＋ δαti …… (70)

In step 910 of the routine for calculating the target steering angle θwti of each wheel shown in FIG. 5, the following equation 71 is used.
According to the target slip angle βt of the vehicle is calculated. βt = ∫ (Gyt / Vx−γt) dt (71)

In step 920, the following equations 72-72 are used.
According to 75, the target traveling direction angle αwti of the ground contact point of each wheel
(I = fl, fr, rl, rr) is calculated. As shown in FIG. 12 for the left front wheel, the target traveling direction angle αwti of the ground contact point is such that the target traveling direction of the ground contact point Pzi (i = fl, fr, rl, rr) of each wheel is relative to the front-rear direction of the vehicle. It is an angle.

[0106] αwtfl = (βt · Vx + Lf · γt) / (Vx−Trf · γt / 2) …… (72) αwtfr = (βt ・ Vx + Lf ・ γt) / (Vx + Trf ・ γt / 2) …… (73) αwtrl = (βt · Vx−Lr · γt) / (Vx−Trr · γt / 2) …… (74) αwtrr = (βt · Vx−Lr · γt) / (Vx + Trr · γt / 2) …… (75)

In step 930, the target steering angle θwti (i = fl, fr, rl, rr) of each wheel is calculated according to the following equation 76.
Is calculated as the difference between the target slip angle αti and the ground contact point target traveling direction angle αwti of each wheel.
Go to 0. θwti = αti-αwti (76)

In step 1010 of the routine for calculating the target braking pressure Pti of each wheel and the target drive torque Tet of the engine shown in FIG. 6, the target longitudinal velocity Vwxti of the ground point of each wheel is calculated according to the following equations 77-80. (I = fl, fr, rl,
rr) is calculated and the target moving speed Vtwti (i = fl, fr, rl, r) of each wheel in the rolling direction is calculated according to the following equation 81.
r) is calculated.

[0109] Vwxtfl = Vx + Trf · γ / 2 (77) Vwxtfr = Vx-Trf.gamma. / 2 (78) Vwxtrl = Vx + Trr.γ / 2 (79) Vwxtrr = Vx-Trr.γ / 2 (80) Vtwti = Vwxti (cos θwti-tanαti · sin θwti) (81)

In step 1020, the target wheel speed Vrwti (i = f) of each wheel is calculated according to the following expression 82 based on the target slip ratio κti and the target moving speed Vtwti in the rolling direction.
l, fr, rl, rr) are calculated. Vrwti = (1-κti) Vtwti (82)

In step 1030, the following equation 83
According to the target longitudinal force Fxt of the vehicle and the lateral force Fyt of the vehicle, the target generated force Fxyt of the vehicle is calculated, and since the following equation 84 is satisfied, the target generated force Fxyt of the vehicle without giving a yaw moment to the vehicle. The target generated force Fxyti (i = fl, fr, rl, rr) of each wheel that achieves the following is calculated in accordance with the following formulas 85 to 88, and is further used as a component of the target generated force Fxyti in the front-rear direction of the wheel. Front-back force F
wxti (i = fl, fr, rl, rr) is calculated according to the following equation 89. In the following formulas 85 to 88, g is a gravitational acceleration.

Fxyt = (Fxt ² + Fyt ² ) ^1/2 (83) Fzfl + Fzfr + Fzrl + Fzrr = Mv · g (84) Fxytfl = Fxyt · Fzfl / (Mv · g) …… (85) Fxytfr = Fxyt · Fzfr / (Mv · g) …… (86) Fxytrl = Fxyt · Fzrl / (Mv · g) …… (87) Fxytrr = Fxyt · Fzrr / (Mv · g) …… (88)

In step 1040, for example, the target wheel acceleration Vrwtdi (i = fl, fr, rl, rr) of each wheel is calculated as the time differential value of the target wheel speed Vrwti, and the effective radius of the wheel is set as Rw. , The target rotational torque Twti (i = fl, fr, rl, rr) of each wheel is calculated according to the following equation 90 with the rotational inertia moment of the wheel as Iw. Twti = Fwxti · Rw + Iw · Vrwtdi (90)

In step 1050, it is determined whether or not the target rotational torque Twti of all wheels is a negative value, that is, it is determined whether or not braking is required for all wheels. If a positive determination is made, step 1
If the negative determination is made in step 080, step 1
Proceed to 060.

In step 1060, the gear ratio Rd of the drive system is obtained based on the shift position Ps, and the distribution ratio of the drive torque of the engine 10 to each wheel by the drive system is Xi (i = fl, fr, rl, rr) (0 <Xi <
0.5, ΣXi = 1), and the target rotation torque Twti of the four wheels
The target drive torque Tet of the engine 10 is calculated according to the following equation 91, where Twtmax is the maximum value of the two, and Xmax is the drive torque distribution ratio of the wheels whose target rotational torque is the maximum value Twtmax (maximum drive torque wheel). . Tet = Twtmax · Rd / Xmax (91)

At step 1070, the target braking pressure Pti of the maximum driving torque wheel is set to 0, and the conversion coefficient between the braking pressure and the braking torque is set to Kp, and the target braking pressure of each wheel other than the maximum driving torque wheel is set. Pti is calculated according to the following equation 92, and then the process proceeds to step 1100. Pti = (Twtmax · Xi / Xmax-Twti) / Kp (92)

In step 1080, the engine 10
The target drive torque Tet of is set to 0, and step 109
At 0, the target braking pressure Pti of each wheel is calculated according to the following equation 93, and then the routine proceeds to step 1100. Pti = -Twti / Kp (93)

Thus, according to the illustrated first embodiment,
In step 100, the target yaw rate γt of the vehicle, the target lateral acceleration Gyt of the vehicle, and the target longitudinal acceleration Gxt of the vehicle are calculated based on the vehicle speed Vx and the like, and in step 150, the target of the vehicle corresponding to the target longitudinal acceleration Gxt of the vehicle. Front-back force F
xt, the target lateral force Fyt of the vehicle corresponding to the target lateral acceleration Gyt,
A target yaw moment Mzt of the vehicle corresponding to the target yaw rate γt is calculated.

Further, in step 200, steering control means
And the control response frequency characteristic G of the braking / driving force control means_αias well as
G_κiIs calculated, and the characteristic G is calculated in step 250._αiOver
And G _κiThe value proportional to the reciprocal of
W_uIs set to, and the distribution control is performed in step 300.
Target slip amount δκti and target slip of each wheel
By calculating the target correction amount δαti of the up angle,
The target slip ratio κti and target slip angle αti of the wheel are played.
Calculated.

Then, in step 900, the target steering angle θwti of each wheel is calculated based on the target slip angle αti,
In step 1000, the target braking pressure Pti of each wheel and the target drive torque Tet of the engine 10 are calculated based on the target slip ratio κti, and in step 1100, the steering angle θwi of each wheel becomes the target steering angle θwti. The front wheel steering device 52 and the rear wheel steering device 64 are the steering angle control device 6
2 is controlled by the wheel cylinder pressure Pi of each wheel
The braking device 42 is controlled so that the target braking pressure Pti becomes
The engine 10 is controlled by the engine control device 26 so that the drive torque Te of the engine 10 becomes the target drive torque Tet.

Therefore, according to the illustrated first embodiment, the target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mt of the vehicle are achieved, in other words, the target yaw rate γt of the vehicle and the target lateral acceleration of the vehicle. It is possible to control the braking / driving force and the steering angle of each wheel so as to achieve Gyt and the target longitudinal acceleration Gxt of the vehicle, whereby the steering control operation amount (steering angle θ) and the driving force control operation amount by the driver ( The vehicle can be stably driven in a desired motion state according to the throttle opening Ta) and the braking control operation amount (brake pedal depression force Fb).

According to the illustrated first embodiment, the control response frequency characteristics G _αi and G _{κi of} the steering control means and the braking / driving force control means are calculated in step 200, and the characteristic G is calculated in step 250. A value proportional to the reciprocal of _{α i} and G _{κ i} is set as the weight W _u in the above equation 10, and in step 300 the target correction amount δκ ti of the slip ratio of each wheel and the target correction amount of the target slip angle by the distribution control. δα
Since ti is calculated, the control target frequency characteristics G _αi and G _{κi of the} steering control means and the braking / driving force control means are control targets for achieving the target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mt of the vehicle. Can be optimally distributed to these control means.

In particular, according to the illustrated first embodiment, the control response frequency characteristic G of the steering control means and the braking / driving force control means G
_{Since α i} and G _{κ i} are calculated every time, changes in the control response frequency characteristics of the steering control means and the braking / driving force control means, for example, changes over time in the actuator 60L and the like, and changes in viscosity due to changes in the temperature of the working oil of the braking device 42. Even if there is a change in the friction coefficient due to a change in the temperature of a friction material such as the brake pad of the braking mechanism of each wheel, the behavior control amount can be appropriately distributed to each control means in response to the change. Therefore, compared with the case where the weight W _{u in the} above formula 10 is set to a constant value in advance, the vehicle travels stably regardless of changes in the control response frequency characteristics of the steering control means and the braking / driving force control means. Can be made. In general, when the vehicle is being accelerated mainly by the driving force of the rear wheels and the yaw direction of the vehicle is controlled by controlling the braking force of the front wheels, the tires of the front wheels are unnecessarily deformed. Then, the use area of the tire becomes a non-linear area, and the control response by the steering control means deteriorates. According to the illustrated first embodiment, the distribution of the control target to these control means is appropriately changed according to the change of the control frequency characteristics of the steering control means and the braking / driving force control means. Even if it is, the vehicle can be stably driven, and unnecessary deformation of the tires of the front wheels can be reduced to prevent deterioration of energy efficiency.

For example, as shown in FIG.
When the input / output frequency response of the braking / driving force control means decreases from the solid line to the broken line, that is, when the time constant T _κi of the above equation 54 decreases, the control response frequency characteristic G _κi decreases, and FIG. As shown in the figure, the weight (W) of the control means in the frequency domain whose response has decreased correspondingly increases, so that the vehicle travels stably regardless of fluctuations in the frequency response of the input / output of the braking / driving force control means. It is possible to properly calculate the control amount of the braking / driving force control means required for this.

Further, as shown in FIG. 19 (A), when the input / output gain of the braking / driving force control means decreases from the solid line to the broken line, that is, when the coefficient T 0 _κi of the above equation 54 decreases, the control response is reduced. The frequency characteristic G _{κi is} also reduced, as shown in FIG.
As shown in (B), since the weight (W) of the control means is correspondingly increased as a whole, the vehicle is stably driven regardless of variations in the input / output gain of the braking / driving force control means. Therefore, it is possible to properly calculate the control amount of the braking / driving force control means.

Further, according to the illustrated first embodiment, the control response frequency characteristic G of the steering control means and the braking / driving force control means.
_{Since α i} and G _{κ i} are calculated for each wheel, and the weight W _{u in the} above equation 10 is also calculated for each wheel, the behavior control amount for stably running the vehicle is steered for each wheel. It can be optimally distributed to the control means and the braking / driving force control means, and the weight W _u is, for example, the control response frequency characteristic G of the entire steering control means and the entire braking / driving force control means.
The steering angle and braking / driving force of each wheel are optimized as compared with the case where _α and G _κ are calculated and the weight W _u is set to a common weight for all wheels as a value proportional to the characteristics G _α and G _κ. Can be controlled.

Second Embodiment FIG. 7 is a flowchart showing the main routine of the steering angle control and braking / driving force control of each wheel in the second embodiment of the vehicle travel control device according to the present invention. In FIG. 7, steps corresponding to the steps shown in FIG. 3 are given the same step numbers as the step numbers given in FIG.

Steps 50 to 150 of this embodiment are executed in the same manner as in the above-described first embodiment, and in step 400 executed after step 150, T
_{o α} is a coefficient, T _α is a time constant, and s is a Laplace operator.
x, lateral force Fy, together with the control response frequency characteristics G _alpha of the steering control means for yaw moment Mz is calculated in the same manner as in the first embodiment described above, the coefficient T _Okappa, the T _kappa The control response frequency characteristic G _κ of the braking / driving force control means with respect to the longitudinal force Fx, lateral force Fy, and yaw moment Mz of the vehicle, which is represented by the following formula 95 with time constant as s Laplace operator, is the above-mentioned first. The calculation is performed in the same manner as in the embodiment. G _α = diag (0, 1 / {T _oα (1 + T _α s)}, 1 / {T _oα (1 + T _α s)}) (94) G _κ = diag (1,0, T _oκ (1 + T _κ) s)) …… (95)

Even in the case of this embodiment, at the start of control,
Control response frequency characteristic G of steering control means_αAnd braking / driving force control
Control response frequency characteristic G of control means_κIs the preset initial
Is set to a value and the control response frequency characteristic G of the steering control means is set._α
Alternatively, the control response frequency characteristic G of the braking / driving force control means_κTo
Characteristic G when it cannot be calculated_αOr G _κ
Is set to the previous value.

In step 450, K_κA positive constant
Before and after the vehicle target to the braking / driving force control means as a coefficient of
Force Fxt_κ, Target lateral force Fyt_κ, Target yaw moment Mzt_κ
Is calculated according to the following equation 96, and K_αThe positive
Before and after the target of the vehicle to the steering control means as a constant coefficient
Force Fst_α, Target lateral force Fyt_α, Target yaw moment Mzt _α
Is calculated according to the following formula 97,
Target longitudinal force Fxt, target lateral force Fyt, target yaw moment M
zt is the control response frequency of the braking / driving force control means and steering control means
Frequency separation is performed based on the number. [Fxt_κ  Fyt_κ  Mzt_κ]^T= K_κG_κ[Fxt Fyt Mzt]^T                                                 …… (96) [Fxt_α  Fyt_α  Mzt_α]^T= K_αG_α[Fxt Fyt Mzt]^T                                                 …… (97)

In step 500, the target slip ratio κti and the target slip angle αti (i = fl, fr, rl, rr) of each wheel by the distribution control according to the routine shown in FIG.
Is calculated, and then steps 900 to 1100 are executed in the same manner as in the above-described first embodiment.

Target slip ratio κ of each wheel shown in FIG.
ti and target slip angle αti calculation routine step 51
0 to 540 are respectively executed in the same manner as steps 310 to 340 of the above-described first embodiment, and in step 550, the weight W _{u κ of} distribution control for the braking / driving force control means is calculated according to the following expression 98. Together with the following equation 9
According to 9, the weight W _{uα of the} distribution control for the steering control means
Is calculated. W _{u κ} = diag (Kb / G _κfl ... Kb / G _κrr ) ...... (98) W _uα = diag (Ks / G _{αfl ・ ・ ・} Ks / G _αrr ) ...... (99)

[0133] longitudinal force of the vehicle about the longitudinal force control means according to the above equation 15 in step 560 Fx, lateral force Fy, with target correction amount of yaw moment Mz delta _kappa is calculated, the steering control according to the above formula 22 longitudinal force of the vehicle to means Fx, lateral force Fy, the target correction amount of yaw moment Mz delta _alpha is calculated.

In step 570, the longitudinal force F of the vehicle
x, lateral force Fy, and yaw moment Mz are partially differentiated by the slip ratio κi of each wheel to calculate the Jacobian J _κ expressed by the above equation 17, and the longitudinal force Fx, lateral force Fy, yaw of the vehicle are calculated. By partially differentiating the moment Mz by the slip angle αi of each wheel, the Jacobian J _α represented by the above equation 27 is calculated.

In step 580, the target correction amount δκti (i = fl, fr, rl,
rr) is calculated, and the target correction amount δαti (i = fl, fr, rl, rr) of the slip angle is calculated according to the above equation 30, and then step 580 is the same as step 380 of the above-described first embodiment. It is executed as in the case.

Thus, according to the illustrated second embodiment,
In step 400, the vehicle longitudinal force Fx, lateral force Fy,
-Control response frequency of steering control means with respect to moment Mz
Number characteristic G_αAnd control response frequency characteristics of braking / driving force control means
G_κIs calculated, and braking / driving force control is performed in step 450.
Target longitudinal force Fxt of the vehicle against the means_κ, Target lateral force Fy
t _κ, Target yaw moment Mzt_κAccording to Equation 96 above
Calculated and before the target of the vehicle to the steering control means
Back force Fst_α, Target lateral force Fyt_α, Target yaw moment Mzt
_αIs calculated according to the above equation 97,
Target longitudinal force Fxt, target lateral force Fyt, target yaw moment M
zt is the control response frequency of the braking / driving force control means and steering control means
Frequency separation is performed based on the number.

Then, in step 500, distribution is performed according to the routine shown in FIG. 8 based on the target longitudinal force, target lateral force, and target yaw moment of the vehicle allocated to the braking / driving force control means and the steering control means by frequency separation. Controlled target slip ratio κti and target slip angle α of each wheel
ti is calculated.

Therefore, according to the second embodiment, the target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mzt of the vehicle are controlled in two ways according to the control response frequencies of the braking / driving force control means and the steering control means. Since the control target distributed to each control means can be distributed to each wheel, the slip of each wheel can be prevented regardless of the change in the control response frequency of the braking / driving force control means or the steering control means. Not only can the rate and slip angle be optimally controlled, but the target behavior control amount of the entire vehicle can be easily distributed to the target control amounts of the braking / driving force control means and the steering control means for each wheel.

According to the first embodiment described above, the determinant of 8 rows and 8 columns must be solved when the target behavior control amount of the entire vehicle is distributed, whereas according to the second embodiment. Since the determinant of 4 rows and 4 columns only needs to be calculated twice,
The calculation amount required for distribution control can be reduced as compared with the case of the first embodiment described above.

Third Embodiment FIG. 9 is a flowchart showing the main routine of the steering angle control and braking / driving force control of each wheel in the third embodiment of the vehicle travel control device according to the present invention. In FIG. 9, steps corresponding to the steps shown in FIG. 3 are given the same step numbers as the step numbers given in FIG.

Steps 50-150 of this embodiment are also above.
Performed as in the first embodiment described above, with steps
In step 600 executed after 150, the above is executed.
The control response frequency characteristic of the steering control means expressed by the equation 94
Sex G_αIs calculated, and steering control is performed in step 650.
Target longitudinal force Fxt of the vehicle against the means_α, Target lateral force Fy
t _α, Target yaw moment Mzt_αAccording to equation 97 above
Is calculated.

In step 700, the target slip angle αti (i = fl, fr, rl, rr) of each wheel by distribution control is calculated in accordance with the routine shown in FIG. 10. In step 800, The target longitudinal force Fxt _κ and the target lateral force Fy of the vehicle with respect to the braking / driving force control means are calculated according to Expression 100.
t _κ and the target yaw moment Mzt _κ are calculated. [Fxt _κ Fyt _κ Mzt _κ ] ^T = [Fxt Fyt Mzt] ^T − [Fxt _α Fyt _α Mzt _α ] ^T …… (100)

In step 850, the target slip ratio κti (i = fl, fr, rl, rr) of each wheel is calculated by distribution control according to the routine shown in FIG. 11, and then steps 900 to 1100 are executed as described above. The same as in the case of the first embodiment of 1.

Steps 710 to 740 of the target slip angle αti calculation routine for each wheel shown in FIG. 10 are executed in the same manner as in steps 310 to 340 of the above-described first embodiment, and at step 750. Is the above formula 9
According to 9, the weight W _{uα of the} distribution control for the steering control means
Is calculated, and in step 760, the vehicle longitudinal force Fx and lateral force Fy related to the steering control means are calculated in accordance with the above equation 22.
Target correction amount of yaw moment Mz delta _alpha is calculated.

In step 770, the longitudinal force F of the vehicle
By partially differentiating x, the lateral force Fy, and the yaw moment Mz by the slip angle αi of each wheel, the Jacobian J _α represented by the above equation 27 is calculated, and in step 780, the slip angle is calculated according to the above equation 30. Target correction amount δ
αti (i = fl, fr, rl, rr) is calculated, and step 79
At 0, the target slip angle αti of each wheel is calculated according to the above equation 58, and then the process proceeds to step 800.

Further, in step 855 of the target slip ratio κti calculation routine for each wheel shown in FIG. 11, the weight W _{u κ of} distribution control for the braking / driving force control means is calculated according to the above equation 98, and step 860 is _executed. in it the above formula 15 longitudinal force Fx of the vehicle about the longitudinal force control means in accordance with the lateral force Fy, the target correction amount of yaw moment Mz delta _kappa is calculated.

At step 870, the longitudinal force F of the vehicle is applied.
By partially differentiating x, lateral force Fy, and yaw moment Mz by the slip ratio κi of each wheel, the Jacobian J _κ expressed by the above expression 17 is calculated, and in step 880, the slip ratio Target correction amount δκ
ti (i = fl, fr, rl, rr) is calculated, and step 890
In this case, the target slip ratio κti of each wheel is calculated according to the above expression 57, and then the process proceeds to step 900.

Thus, according to the illustrated third embodiment,
Control response frequency of steering control means in step 600
Characteristic G_αIs calculated and the control response is given in step 650.
Frequency characteristic G_αThe target longitudinal force Fxt and the target lateral force of the vehicle
Force Fyt and target yaw moment Mzt are distributed to steering control means
As a result of the
Back force Fxt_α, Target lateral force Fyt_α, Target yaw moment Mzt
_αIs calculated, and in step 700, the steering control means
Target longitudinal force Fxt against the vehicle_α, Target lateral force Fyt _α,Target
Yaw moment Mzt_αTarget slip angle of each wheel based on
αti is calculated.

Then, in step 800, the target of the vehicle
The longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mzt
The target longitudinal force Fxt of the vehicle to the steering control means
_α, Target lateral force Fyt_α, Target yaw moment Mzt_αSubtract
Before and after the vehicle target to the braking / driving force control means
Force Fxt_κ, Target lateral force Fyt_κ, Target yaw moment Mzt _κ
Is calculated, and in step 850, the target longitudinal force Fx
t_κ, Target lateral force Fyt_κ, Target yaw moment Mzt_κBased on
Then, the target slip ratio κti of each wheel is calculated.

Therefore, according to the third embodiment, the target angle control amount Fxt, Fyt, Mzt of the entire vehicle is preferentially distributed to the steering control means by using the steering angle control means as the control means of the highest priority. Thus, the target behavior control amounts Fxt _α , Fyt _α , Mzt _α of the steering control means are calculated, and the target behavior control amounts Fxt, Fyt, Mzt of the entire vehicle and the target behavior control amounts Fxt _α , Fyt _{α of} the steering control means, Since the difference from Mzt _α is calculated as the target behavior control amounts Fxt _κ , Fyt _κ , and Mzt _κ of the braking / driving force control means, the vehicle may be unnecessarily accelerated or decelerated by the behavior control by the braking / driving force control means. It is possible to reliably control the behavior of the vehicle and to make the vehicle travel stably while reducing the above.

Further, according to the third embodiment, the target behavior control amounts Fxt _α , Fyt _α , Mzt _{α of} the steering control means and the target behavior control amounts Fxt _κ , Fyt _κ , Mzt of the braking / driving force control means are provided.
_κ is calculated, and the target behavior control amounts Fxt _α , Fyt _α , Mzt _α
Is distributed to each wheel, the target control amount of the steering control means, that is, the target slip angle αti is calculated for each wheel, and the target behavior control amounts Fxt _κ , Fyt _κ , and Mzt _κ are distributed to each wheel. Since the target control amount of the braking / driving force control means, that is, the target slip ratio κti is calculated by each of the wheels, the calculation amount necessary for the distribution control can be reduced as in the case of the second embodiment described above. .

Fourth Embodiment FIG. 13 shows a steering angle control and control of each wheel in a fourth embodiment of the traveling control system for a vehicle according to the present invention, which is constructed as a modification of the above-mentioned first embodiment . 6 is a flowchart showing a main routine of driving force control. In addition, in FIG.
Steps corresponding to the steps shown in FIG. 3 are given the same step numbers as the step numbers given in FIG.

Steps 50 to 200 and steps 250 to 1100 of this embodiment are executed in the same manner as in the above-described first embodiment, and tuck-in occurs in step 210 executed after step 200. It is determined whether or not the determination is made. If the determination is negative, the process proceeds to step 230. If the determination is positive, the coefficient Kb of the distribution control weight W _u is set to 0 in step 220. Except for the above, the distribution control weight W _u is calculated in the same manner as in the case of the first embodiment described above.

In step 230, it is determined whether or not the vehicle is in the rapid turning acceleration state. If a negative determination is made, the process proceeds to step 250, and if a positive determination is made, the weight W of the distribution control is determined. _The distribution control weight W _u is calculated in the same manner as in the case of the above-described first embodiment except that the coefficient Ks of _u is set to 0.

Thus, according to the illustrated fourth embodiment,
In step 210, it is determined whether or not tuck-in has occurred, and in step 230, it is determined whether or not the vehicle is in the rapid turning acceleration state, and the tuck-in does not occur and the vehicle turns. If the vehicle is not in the rapid acceleration state, step 250 and subsequent steps are executed, whereby the same control as in the case of the above-described first embodiment is performed.

On the other hand, when the tack-in occurs, an affirmative determination is made in step 210, and the coefficient Kb is set to 0 in step 220, so that the distribution weight to the braking / driving force control means is 0. Is set to
In that state, step 300 and subsequent steps are executed, whereby the target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mzt of the vehicle are distributed only to the steering control means, so that the slip angle of each wheel is set to an appropriate value. It is possible to surely control and reduce the tuck-in to effectively secure the traveling stability of the vehicle.

When no tuck-in has occurred but the vehicle is in the sudden turning acceleration state, an affirmative decision is made in step 230, and the coefficient Ks is set to 0 in step 240, whereby the steering control means is instructed. The distribution weight is set to 0, and step 300 and subsequent steps are executed in that state, whereby the target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mzt of the vehicle are distributed only to the braking / driving force control means. , The slip ratio of each wheel is surely controlled to an appropriate value to reduce the risk that the slip ratio becomes excessive and the lateral force of the wheel decreases due to the slip ratio, thereby effectively improving the running stability of the vehicle. Can be secured.

In the illustrated fourth embodiment, when the tuck-in occurs, the target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mzt as the target behavior control amount of the vehicle are the steering control means. The target longitudinal force Fxt, the target lateral force Fyt, and the target yaw moment Mzt of the vehicle are distributed only to the braking / driving force control means when the vehicle is in the turning rapid acceleration state without any tuck-in. However, when the tack-in occurs, the distribution ratio of the target behavior control amount to the steering control means is increased and the distribution ratio to the braking / driving force control means is reduced as compared with the normal time, and the tack-in does not occur. When the vehicle is in the rapid turning acceleration state, the distribution ratio of the target behavior control amount to the steering control means is reduced and the distribution ratio to the braking / driving force control means is increased. It may be so that corrected.

Fifth Embodiment FIG. 14 shows a steering angle control and control of each wheel in a fifth embodiment of the vehicle travel control device according to the present invention, which is constructed as a modification of the above-mentioned third embodiment . 6 is a flowchart showing a main routine of driving force control. In addition, in FIG.
The steps corresponding to the steps shown in FIG. 9 are given the same step numbers as the step numbers given in FIG.

Steps 50 to 150 and steps 600 to 1100 of this embodiment are executed in the same manner as in the above-described first embodiment, and in step 160 executed after step 150, the target yaw rate of the vehicle. Drift value D indicating the degree of the vehicle's drift-out state as the absolute value of the deviation between γt and the actual yaw rate γ of the vehicle
V is calculated, and it is determined whether or not the drift value DV is equal to or greater than the reference value DVo (a positive constant), that is, in a situation where the degree of drift-out of the vehicle is large and the estimation accuracy of the vehicle slip angle β is low. It is determined whether or not there is,
When a negative determination is made, the routine proceeds to step 600, and when an affirmative determination is made, the routine proceeds to step 1200.

In step 1200, the control response frequency characteristic G _κ of the braking / driving force control means is calculated according to the above equation 95, and in step 1300 the target longitudinal force Fxt _κ of the vehicle with respect to the braking / driving force control means, the target The lateral force Fyt _κ and the target yaw moment Mzt _κ are calculated according to the above equation 96.

In step 1400, the target slip ratio κ _ti (i = fl, fr, rl, rr) of each wheel is calculated by the distribution control according to the routine shown in FIG. 16. In step 1500, The target longitudinal force Fxt _α of the vehicle with respect to the steering control means, the target lateral force Fyt _α ,
The target yaw moment Mzt _α is calculated, and step 160
At 0, the target slip angle αti (i = fl, fr, r of each wheel by distribution control according to the routine shown in FIG. 17).
l, rr) is calculated, and then the process proceeds to step 900. [Fxt _α Fyt _α Mzt _α ] ^T = [Fxt Fyt Mzt] ^T − [Fxt _κ Fyt _κ Mzt _κ ] ^T …… (101)

It should be noted that 1410 to 1450 of the target slip ratio κti calculation routine for each wheel shown in FIG. 16 are executed in the same manner as in steps 855 to 890 in the third embodiment described above, and FIG. Steps 1610 to 169 of the target slip angle αti calculation routine of each wheel shown in FIG.
0 is step 7 in the above-mentioned third embodiment.
It is executed as in the case of 10-790.

Thus, according to the illustrated fifth embodiment,
In step 160, it is determined whether or not the estimation accuracy of the vehicle slip angle β is low by determining whether or not the drift value DV indicating the degree of the vehicle drift-out state is equal to or greater than the reference value DVo. If the drift value DV is less than the reference value DVo, step 60
By executing 0 and subsequent steps, the same control as in the case of the above-described third embodiment is performed by using the steering control means as the behavior control means having the highest priority, so that the vehicle may be unnecessarily accelerated or decelerated. It is possible to stably drive the vehicle while reducing the above.

On the other hand, when the drift value DV is equal to or greater than the reference value DVo, an affirmative determination is made in step 160 and steps 1200 to 1600 are executed, whereby the target longitudinal force Fxt and the target lateral force Fyt of the vehicle are set. ,
Since the target yaw moment Mzt is distributed only to the braking / driving force control means, and the traveling behavior of the vehicle is controlled by using the braking / driving force control means as the behavior control means of the highest priority, the degree of the drift-out state of the vehicle is large. It is possible to reliably prevent the behavior control by the steering control unit from being inappropriately performed due to the low estimation accuracy of the slip angle β, and thereby prevent the running stability of the vehicle from being poorly controlled.

According to each of the above-mentioned embodiments, since all four wheels are steered, it is possible to surely improve the running stability of the vehicle as compared with the case where only the front wheels are steered.
Further, since the slip ratio of each wheel is controlled by controlling the engine output in addition to the braking force of each wheel, the running stability of the vehicle is surely improved as compared with the case where the engine output is not controlled. be able to.

Although the present invention has been described in detail above with reference to specific embodiments, the present invention is not limited to the above-mentioned embodiments, and various other embodiments are also possible within the scope of the present invention. It will be apparent to those skilled in the art that

For example, in each of the above-described embodiments, the behavior control characteristics of the plurality of behavior control means are the control response frequency characteristics of each control means, but the behavior control characteristics are the characteristics relating to the control response of each control means. As long as it is, the calculation may be performed in a mode other than the above formulas.

In each of the above-described embodiments, the plurality of behavior control means for controlling the behavior of the vehicle in cooperation with each other by the different actions are the steering control means and the braking / driving force control means. The behavior control means in the above is not limited to these. For example, the behavior control means may be a combination of steering control means, braking / driving force control means, and ground load control means for controlling the ground load of each wheel. .

In each of the above-mentioned embodiments, the slip ratio of each wheel is controlled to the target slip ratio by controlling the braking force of each wheel and the output of the engine. It may be modified so that only the braking force of the wheels is controlled and the output of the engine is not controlled.

In each of the above embodiments, the vehicle is a four-wheel drive vehicle, and the braking force and steering angle of all four wheels are controlled. It may be applied to a vehicle or a rear-wheel drive vehicle, or may be applied to a vehicle in which only front wheels are steered.

In each of the above-mentioned embodiments, the control response frequency characteristic of the steering control means and the braking / driving force control means and the weight W _{u of the} distribution control are calculated for each cycle. In general, the control response frequency characteristic of each control means does not change abruptly, so the control response frequency characteristic and the weight W _{u of the} distribution control may be modified so as to be calculated every predetermined cycle.

In each of the above embodiments, the vehicle 1
2 has an engine 10 as a drive source and a drive system for transmitting the drive torque of the drive source to each wheel at a constant distribution ratio, and the braking / driving force control means controls the drive torque of the engine 10 Driving force control means (engine control device 26) for comprehensively controlling the driving force of each wheel, and braking force control means (braking device 42 and electronic control device 50) capable of individually controlling the braking force of each wheel. But
By configuring the vehicle as, for example, a so-called wheel-in-motor type vehicle, the driving force control unit can individually control the driving force of each wheel, and the braking force control unit can individually control the braking force of each wheel. May be configured to be

Further, in each of the above-mentioned embodiments, the effective length of the tie rods 58L, 58L, 68L, 68R of the hydraulic power steering devices 56, 66 of each wheel is variable by the actuators 60L, 60L, 70L, 70R. The wheels are steered by being controlled, but each wheel may be steered by a steering device individually provided.

Further, in the illustrated fourth embodiment, whether or not there is a possibility that the behavior of the vehicle may deteriorate depending on the distribution of the behavior control amount according to the behavior control characteristic of each behavior control means. Judgment is made by judging whether tuck-in is occurring and whether the vehicle is in a rapid turning acceleration state, but by allocating the behavior control amount according to the behavior control characteristics of each behavior control means. On the contrary, the determination as to whether or not the behavior of the vehicle may be deteriorated may be determined based on other vehicle conditions.

Further, in the illustrated fifth embodiment, the behavior control means of the highest priority is normally set in the steering control means, and the behavior control of the highest priority is given when the drift value DV is equal to or higher than the reference value. Although the means is changed to the braking / driving force control means, the determination of whether or not the change of the behavior control means of the highest priority is necessary is made by, for example, detecting the parameter for controlling each behavior control means. The detection accuracy of the sensor, the estimation accuracy of the estimated slip angle β of the vehicle body, whether the slip angle of the tire or the estimated slip angle of the vehicle body exceeds the reference range. Good.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a vehicle travel control device according to the present invention.

FIG. 2 is a block diagram showing a control system of the first embodiment.

FIG. 3 is a flowchart showing a main routine of travel control in the first embodiment.

FIG. 4 step 30 of the flowchart shown in FIG.
6 is a flowchart showing a routine for calculating a target slip ratio κti and a target slip angle αti of each wheel at 0.

FIG. 5 is a step 90 of the flowchart shown in FIG.
7 is a flowchart showing a routine for calculating a target steering angle θwti of each wheel at 0.

FIG. 6 is step 10 of the flowchart shown in FIG.
10 is a flowchart showing a target braking pressure Pti of each wheel and a target drive torque Tet calculation routine of the engine in 00.

FIG. 7 is a flowchart showing a main routine of travel control in a second embodiment of the vehicle travel control device according to the present invention.

FIG. 8 is step 50 of the flowchart shown in FIG.
6 is a flowchart showing a routine for calculating a target slip ratio κti and a target slip angle αti of each wheel at 0.

FIG. 9 is a flowchart showing a main routine of travel control in a third embodiment of the vehicle travel control device according to the present invention.

FIG. 10 is step 7 of the flowchart shown in FIG.
10 is a flowchart showing a target slip angle αti calculation routine of each wheel in 00.

FIG. 11 Step 8 of the flowchart shown in FIG.
5 is a flowchart showing a target slip ratio κti calculation routine of each wheel in 50.

FIG. 12 is an explanatory diagram showing a target traveling direction angle αwtfl of a ground contact point of a wheel for the left front wheel.

FIG. 13 is a flowchart showing a main routine of travel control in a fourth embodiment of the vehicle travel control device according to the present invention.

FIG. 14 is a flowchart showing a main part of a main routine of travel control in the fifth embodiment of the vehicle travel control device according to the present invention.

FIG. 15 is a flowchart showing the remaining part of the main routine of the travel control in the fifth embodiment of the vehicle travel control device according to the present invention.

16 is a flowchart showing a routine for calculating a target slip ratio κti of each wheel in step 1400 of the flowchart shown in FIG.

17 is a flowchart showing a target slip angle αti calculation routine of each wheel in step 1600 of the flowchart shown in FIG.

FIG. 18 is a graph for explaining the operation of the first embodiment when the input / output frequency response of the braking / driving force control means is lowered.

FIG. 19 is a graph for explaining the operation of the first embodiment when the input / output gain of the braking / driving force control means is reduced.

[Explanation of symbols]

10 ... Engine 12 ... vehicle 16 ... Transmission 18 ... Center differential 26 ... Engine control device 42 ... Braking device 44 ... Hydraulic circuit 50 ... Electronic control device for traveling control 52 ... Front wheel steering device 62 ... Rudder angle control device 64 ... Rear wheel steering device 72 ... Vehicle speed sensor 74 ... longitudinal acceleration sensor 76 ... Lateral acceleration sensor 78 ... Yaw rate sensor 80 ... pedal force sensor 82i ... Wheel speed sensor 84i ... Pressure sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60T 8/58 ZYY B60T 8/58 ZYYE B62D 6/00 B62D 6/00 // B62D 113: 00 113: 00 137: 00 137: 00 (72) Yoshikazu Hattori Yoshikazu Hattori A-41 Nagakute-cho, Aichi-gun, Aichi Prefecture 1-41 Yokomichi Yokomichi F-term in Toyota Central Research Laboratory Co., Ltd. (reference) 3D032 CC02 DA03 DA04 DA24 DA25 DA29 DA33 DA47 DA48 DA49 DA92 DA93 DD02 EB04 EB16 EB17 EB21 FF01 FF07 FF08 GG01 3D041 AA37 AA40 AA47 AA66 AA71 AB01 AC00 AC01 AC26 AC30 AD02 AD04 AD10 AD50 AD51 AE00 AE02 AE41 AF01 3D046 BB21 CC02 GG02 GG10 HH02 HH05 HH07 HH08 HH16 HH17 HH21 HH22 HH25 HH26 HH35 HH36 HH39 JJ06

Claims (7)

[Claims] 1. A plurality of behavior control means for controlling the behavior of a vehicle in cooperation with each other by different actions, a means for calculating a target behavior control amount of the entire vehicle for stably traveling the vehicle, and a plurality of the plurality of behavior control means. And a distribution control means for distributing the target behavior control amount of the entire vehicle to the plurality of behavior control means according to the behavior control characteristics of the behavior control means, and controlling the plurality of behavior control means based on the distribution result. The travel control device for a vehicle according to claim 1, wherein the distribution control means has means for sequentially detecting behavior control characteristics of the behavior control means. 2. A plurality of behavior control means for controlling the behavior of the vehicle in cooperation with each other by different actions, a means for calculating a target behavior control amount of the entire vehicle for stably traveling the vehicle, and a plurality of the plurality of behavior control means. And a distribution control means for distributing the target behavior control amount of the entire vehicle to the plurality of behavior control means according to the behavior control characteristics of the behavior control means, and controlling the plurality of behavior control means based on the distribution result. In the travel control device, the distribution control means may worsen the behavior of the vehicle depending on the distribution of the target behavior control amount of the entire vehicle according to the behavior control characteristics of the plurality of behavior control means. A traveling control device for a vehicle, comprising: a determining unit that determines whether or not the target behavior control amount of the entire vehicle is changed according to a determination result of the determining unit. 3. The plurality of behavior control means individually control the steering control means for steering the wheels independently of the steering operation by the driver and the braking / driving force of each wheel independently of the braking / driving operation by the driver. 3. The vehicle travel control device according to claim 1, further comprising a braking / driving force control means capable of controlling the driving force. 4. The distribution control means sets a distribution weight of a target behavior control amount of the entire vehicle according to the behavior control characteristics of the steering control means and the braking / driving force control means, and the distribution weight sets the distribution weight of the target behavior control amount of the entire vehicle. 4. The vehicle travel control device according to claim 3, wherein the target behavior control amount of the entire vehicle is distributed to the steering control means and the braking / driving force control means. 5. The distribution control means detects control response frequencies of the steering control means and the braking / driving force control means, and based on the detected control response frequencies of the steering control means and the braking / driving force control means. 4. The vehicle according to claim 3, wherein the target behavior control amount of the entire vehicle is distributed to the steering control means and the braking / driving force control means by frequency-separating the target behavior control amount of the entire vehicle. Travel control device. 6. A plurality of behavior control means for controlling the behavior of a vehicle in cooperation with each other by different actions, a means for calculating a target behavior control amount of the entire vehicle for stably traveling the vehicle, and a plurality of the plurality of behavior control means. And a distribution control means for distributing the target behavior control amount of the entire vehicle to the plurality of behavior control means according to the behavior control characteristics of the behavior control means, and controlling the plurality of behavior control means based on the distribution result. In the traveling control device, the distribution control means is means for calculating a distribution amount of the target behavior control amount of the entire vehicle to the behavior control means of the highest priority according to the behavior control characteristics of the plurality of behavior control means. A vehicle travel control device comprising: a means for distributing a difference between the target behavior control amount of the entire vehicle and the distribution amount to another behavior control means. 7. The plurality of behavior control means individually control the steering control means for steering the wheels independently of the steering operation by the driver and the braking / driving force of each wheel independently of the braking / driving operation by the driver. 7. A vehicle travel control device according to claim 6, further comprising a possible braking / driving force control means, wherein the behavior control means having the highest priority is the steering control means.