JP2008247067A - Motion control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent or suppress a situation in which a vehicle suddenly becomes unstable. <P>SOLUTION: A controller U changes and controls transverse force fxi and longitudinal force fyi to each of four tires 1FL-1RR (i=1 to 4, and an identifier for discriminating each tire) so as to attain a target transverse force, a target longitudinal force and a target yaw moment. Based on the tire force detected by a tire force detection sensor 20 and maximum tire force fmaxi obtained in each tire, load rate ηi of each tire is determined. The four tires are divided to two sets of tires composed of two diagonally located tires, and the tire force of each tire is changed and controlled so that load rates (η1 and η4, η2 and η3) of each pair of tires (1FL and 1RR, 1FR and 1RL) are mutually uniformed, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle motion control apparatus.

As one of techniques for performing vehicle motion control, in particular posture control, a technique has been proposed in which the tire force of each tire is independently changed and controlled. Japanese Patent Application Laid-Open No. H10-228688 proposes a control that controls the load factors of four tires, front, rear, left, and right, to be equal to each other. Here, the tire force is a force obtained by synthesizing the lateral force acting on the tire and the longitudinal force, and the ratio of the actual tire force to the maximum tire force that can be generated by the tire is the load factor of the tire. In other words, the differential force between the maximum tire force and the actual tire force is a tire margin force, and the ratio of the differential force to the maximum tire force is a tire margin rate. The maximum tire force is determined mainly by the tire contact load and the road surface μ (μ is a friction coefficient).
JP 2005-145256 A

  By the way, the motion control that changes and controls the tire force of each tire independently is performed when each tire is operated when a steering wheel is operated by a driver, when a brake is operated, or when an accelerator pedal is depressed. This is important in a transition period in which the tire force of the vehicle is greatly changed and the posture state of the vehicle becomes unstable, and is particularly important as control near the limit of the vehicle, such as when an obstacle avoidance operation is performed.

  From this point of view, when examining the technique described in Patent Document 1, it is controlled so that the load factor of all the front, rear, left and right tires is equal. Although it is preferable from the viewpoint of doing, it is also a control that actively creates a state where the load factor of each tire is close to 100%, and the tire force of all tires is saturated simultaneously (the load factor of each tire is 100 at the same time). It will be easy to make a situation). When the tire forces of all the tires are saturated, it becomes impossible to control the posture of the vehicle, and the vehicle suddenly becomes unstable.

  The present invention has been made in view of the above circumstances, and its purpose is to prevent a situation in which the vehicle suddenly becomes unstable when the tire force of each tire is changed and controlled independently. Another object of the present invention is to provide a vehicle motion control device that can be suppressed.

In order to achieve the above object, the following solution is adopted in the present invention. That is, as described in claim 1 in the claims,
A vehicle motion control device capable of changing and controlling the lateral force and the longitudinal force on the front, rear, left and right tires,
Tire force detecting means for detecting the actual tire force of each tire;
Load factor determining means for determining the load factor of each tire based on the tire force detected by the tire force detecting means and the maximum tire force obtained by each tire;
The front / rear / right / left tires are divided into two pairs of tires that are paired with two diagonally located tires, and the tire force of each tire is changed and controlled so that the load factors of the paired tires are equal to each other. Tire force distribution control means;
It is supposed to be equipped with.

  According to the above solution, since the tire forces of two paired tires located on the diagonal are controlled to be equal to each other, the left and right front wheel tires, the left and right rear wheel tires, the right front and rear tires This is a control that creates a state where the tire forces of the tires of the left and right and left and right are different from each other, preventing or suppressing the situation where the tire forces of all tires are saturated almost simultaneously, This is preferable in preventing or suppressing the situation of becoming unstable.

A preferred mode based on the above solution is as described in claim 2 and the following claims. That is,
The tire force distribution control means further controls to change the tire force of each tire so that the load factor of the paired tires is minimized (corresponding to claim 2). In this case, it is preferable to secure a sufficient tire force to cope with an avoidance operation by the driver while minimizing the tire load.

  Further, the tire force distribution control means changes and controls the tire force of each tire so that the load factors of the two front and left tires are minimized (corresponding to claim 3). In this case, it is preferable to secure a sufficient tire force to cope with an avoidance operation by the driver while minimizing the tire load.

  The tire force of each tire is changed by changing at least one of a steering angle, a braking force, and a driving force for each tire (corresponding to claim 4). In this case, the tire force can be distributed and controlled in accordance with changes in the steering angle, braking force, and driving force, which have a great influence on the tire force and are often changed according to the driver's steering intention. .

With suspension control means for performing roll control or pitch control of the vehicle body,
The tire force distribution control means further controls the maximum tire force of each tire by controlling the suspension control means;
(Corresponding to claim 5). In this case, by actively changing and controlling the contact load of each tire, the maximum tire force for each tire can be changed and controlled, and the degree of freedom of tire force distribution control can be further increased.

  Further, the tire force distribution control means controls the tire forces of the left and right front wheels to be different from each other (corresponding to claim 6). In this case, the situation in which all tire forces are saturated almost simultaneously can be prevented or suppressed more reliably.

The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi to be distributed to each tire so that the evaluation function J based on the following equation (1) is minimized (corresponding to claim 7). ). In this case, more specific control for performing distribution control of tire force corresponding to claim 1 is provided. In particular, the distribution control of the tire force can be performed by a simple calculation method of minimizing control of the evaluation function J.
J = K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |) −− (1)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K2 = Weighting factor (0 <K2)

The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi distributed to each tire so that the evaluation function J based on the following equation (2) is minimized (corresponding to claim 8). ). In this case, more specific control for performing distribution control of tire force corresponding to claim 2 or claim 3 is provided. In particular, the distribution control of the tire force can be performed by a simple calculation method of minimizing control of the evaluation function J.
J = K1 × (η1 + η2)
+ K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |) −− (2)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K1 = Weighting factor (0 <K1)
K2 = weighting coefficient (0 <K2)

The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi distributed to each tire so that the evaluation function J based on the following equation (3) is minimized (corresponding to claim 9). ). In this case, more specific control for performing tire force distribution control corresponding to claim 6 is provided. In particular, the distribution control of the tire force can be performed by a simple calculation method of minimizing control of the evaluation function J.
J = K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |)
+ K3 × (| η1-η2 | −α) −− (3)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K2 = Weighting factor (0 <K2)
K3 = weighting coefficient (0 <K3)
α = Load factor of a predetermined difference to be set between η1 and η2

The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi distributed to each tire so that the evaluation function J based on the following equation (4) is minimized (corresponding to claim 10). ). In this case, more specific control for performing tire force distribution control corresponding to claims 2, 3, and 6 is provided. In particular, the distribution control of the tire force can be performed by a simple calculation method of minimizing control of the evaluation function J.
J = K1 × (η1 + η2)
+ K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |)
+ K3 × (| η1-η2 | −α) −− (4)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K1 = Weighting factor (0 <K1)
K2 = weighting coefficient (0 <K2)
K3 = weighting coefficient (0 <K3)
α = Load factor of a predetermined difference to be set between η1 and η2

  ADVANTAGE OF THE INVENTION According to this invention, when changing and controlling the tire force of each tire independently, the situation where a vehicle becomes unstable rapidly can be prevented or suppressed.

  In FIG. 1, an automobile VC as a vehicle has a left front wheel 1FL, a right front wheel 1FR, a left rear wheel 1RL, and a right rear wheel 1RR. It shall be named generically as 1. Moreover, the code | symbol used about the wheel may be used as a code | symbol about the tire. Each wheel 1 is held so as to be swingable in the vertical direction with respect to the vehicle body via a suspension arm or the like. Each wheel 1 can independently change its turning angle, braking force, and driving force, and can also change the ground load. For this reason, each wheel 1 is provided with a steering angle control device 10, a braking force control device 11, a driving force control device 12, and a suspension control device 13 independently.

  The rudder angle control device 10 can be configured using, for example, a hydraulic or electric actuator that applies a force for turning each wheel 1. The braking force control device 11 can be configured by using, for example, a hydraulic or electric actuator that adjusts the braking force applied to the wheel 1, and in particular, ABS that is often installed in recent vehicles. A control device or a traction control device can be used.

  The driving force control device 12 can be configured to control the torque distribution of the driving force from the engine or motor for each wheel, and in addition, each wheel 1 has a driving motor independently. Can be configured to control the torque generated by each drive motor. The suspension control means 13 may be configured to control a vehicle height adjusting cylinder device used in a so-called active suspension control device.

  Each wheel 1 is provided with a tire force sensor 20 that independently detects the tire force and the like. As the tire force sensor 20, for example, a 6-component force sensor incorporated in a hub that holds each wheel 1 can be used. With this six component force sensor, it is possible to detect the force acting on the wheel (that is, the tire) in each of the left, right, front, back, and top and bottom directions.

  In FIG. 1, U is a controller (control unit) configured using a microcomputer, and this controller U controls the tire force distribution of each wheel 1 as will be described later. The entire control system including the controller U is shown in block diagram form in FIG. In FIG. 2, the controllers U to 13 are controlled by the controller U. For this reason, in addition to the signal from the tire force sensor 20 described above, signals from various sensors S1 to S5 are input to the controller U. The sensor S1 is a brake sensor that detects the depression amount of the brake pedal. The sensor S2 is an accelerator sensor that detects the amount of depression of the accelerator pedal (accelerator opening). The sensor S3 is a handle sensor that detects an operation amount of the handle 15 (see FIG. 1). The sensor S4 is a μ sensor that detects the road surface μ (friction coefficient) (see also FIG. 1).

  The controller U determines the target longitudinal force Fyo, the target lateral force Fxo, and the target yaw moment YMo at the center of gravity of the vehicle body based on the signals from the sensors S1 to S4 described above. Then, the tire force of each wheel 1 (each tire) is independently controlled as described later so as to satisfy the target longitudinal force Fyo, the target lateral force Fxo, and the target yaw moment YMo.

  Here, the tire force will be described with reference to FIG. First, the circle indicated by Fmax is a friction circle, which is the maximum tire force. This maximum tire force Fmax is determined by the contact load and the road surface μ. The longitudinal force acting on the tire is indicated by Fy, and the lateral force is indicated by Fx. The combined force Fxy of the longitudinal force Fy and the lateral force Fx is an actual tire force, and the tire force Fxy is “(Fx squared + Fy squared) 1/2 power”. The ratio of the tire force Fxy to the maximum tire force Fmax is the load factor η. Further, the differential force Δf obtained by subtracting the tire force Fxy from the maximum tire force Fmax is a surplus force of the tire force that can be further exhibited, and the ratio of the differential force Δf to the maximum tire force is the tire margin rate.

  In the motion control, it is important that the tire force Fxy does not exceed the maximum tire force Fmax for each tire (the load factor is less than 100%). In particular, it is important to prevent or suppress a sudden change in the attitude of the vehicle so that all the wheels 1 do not exceed the load factor of 100% almost simultaneously.

  In the present invention, for the four wheels 1, control is performed assuming a pair of wheels located on a diagonal line (located on a diagonal line in plan view). That is, as shown in FIGS. 5 and 6, the left front wheel 1FL and the right rear wheel 1RR constitute a pair of wheels (tires), and similarly, the right front wheel 1FR and the left rear wheel 1RL form a pair (wheels). Tire).

  In the present invention, the load factor η1 of the paired left front wheel (tire) 1FL and the load factor η4 of the right rear wheel 1RR (tire) are controlled to be equal to each other. Similarly, the load factor η2 of the paired right front wheel (tire) 1FR and the load factor η3 of the left rear wheel 1RL (tire) are controlled to be equal to each other.

  5 and 6 show the actual tire force distribution control. That is, FIG. 5 shows a state in which the vehicle is stably driven (straight-running steady operation state), the load factors η1 to η4 of the tires of each wheel are substantially the same value, and there is a margin in the tire force. There is a state. When the brake operation, the accelerator stepping operation or the steering wheel operation is performed from the state of FIG. 5 and the vehicle is in the vicinity of the limit of the vehicle, the distribution state of the tire force to each tire is changed, for example, as shown in FIG. . In the state of FIG. 6, the load factor η2 of the right front wheel (tire) 1FR that forms the first pair and the load factor η3 of the left rear wheel 1RL (tire) are made equal to each other and almost saturated. The value is changed to a state where there is almost no surplus tire force. On the other hand, the load factor η1 of the other pair of left front wheel (tire) 1FL and the load factor η4 of the right rear wheel 1RR (tire) are set to be large values while being equal to each other. As compared with η3, the degree of increase is small, and a sufficient tire force still remains.

  As apparent from the state of FIG. 6, when attention is paid to the front part of the vehicle body, sufficient tire force remains in the left front wheel 1FL, and when attention is paid to the rear part of the vehicle body, sufficient tire force remains in the right rear wheel 1RR. If attention is paid to the portion, sufficient tire force remains in the left front wheel 1EL, and if attention is paid to the right side of the vehicle body, sufficient tire force remains in the right rear wheel 1RR. As described above, since the tire load factors of all the wheels do not saturate almost simultaneously, a situation in which the vehicle suddenly becomes unstable is prevented or suppressed.

  Here, FIG. 4 shows the relationship between avoidance steering by the driver and vehicle responsiveness (degree of driver's response request). When the avoidance steering indicated by symbol H1 is small, the front-rear response is strongly required compared to the lateral response and yaw response, and when avoidance steering is increased to the range indicated by symbol H2, the lateral response and yaw response are increased. When the responsiveness and the front / rear response are required to be approximately the same, and the avoidance steering is further increased to the range indicated by the symbol H3, the lateral response and the yaw response are required more strongly than the front / rear response. In the motion control of the vehicle, it becomes important in the range from the range H2 to the range H3, and particularly important in the range H3 that approaches the limit of the vehicle H3. As is clear from the description given above with reference to FIGS. 5 and 6, wheels (tires) with sufficient remaining tire force remaining in any part of the front part of the vehicle body, the rear part of the vehicle body, the left side part of the vehicle body, and the right side part of the vehicle body. It is possible to prevent or suppress a situation in which the vehicle suddenly becomes unstable (when the driver further performs an avoidance operation from the state of FIG. There is still enough tire power to change the posture state of

  The tire force distribution control described above is performed, for example, by determining the tire forces Fxi and Fyi (i = 1 to 4) of each tire so as to minimize the evaluation function J shown in the following equation (A). .

J = K1 × (η1 + η2)
+ K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |) −− (A)

However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K1 = Weighting factor (0 <K1)
K2 = weighting coefficient (0 <K2)

  In the above formula (A), the term of K2 is control so that η1 = η4 and η2 = η3. Similarly, the term K1 is a control that minimizes the total value of the load factors η1 and η2 of the left and right front tires (the load factor of the paired tires located on the diagonal line is minimized). Control). Alternatively, K1 = 0 can be set. In this case, the control that minimizes the total value of the load factors η1 and η2 is not executed.

  Each tire force Fxi, Fyi as a tire force distribution target value obtained by the above formula (A) is replaced with a target turning angle and a target slip ratio with reference to a tire model stored in advance in the controller U. Thus, the steering angle control device 10, the braking force control device 11, and the driving force control device 12 are controlled so as to achieve the target turning angle and the target slip ratio for each wheel (tire). An example of the results is shown in FIG.

  Next, an example of the above-described tire force distribution control will be described with reference to the flowchart shown in FIG. In the following description, Q indicates a step. First, in Q1, after signals from various sensors are read, in Q2, the target lateral force Fxo and the target are determined even at the center of gravity of the vehicle body, for example, from the steering angle of the vehicle, the brake depression amount, the accelerator opening, etc. The longitudinal force Fyo and the target yaw moment YMo are determined. Thereafter, in Q3, the maximum tire force fmaxi (i = 1 to 4) of each tire is determined based on the ground contact load detected by the tire force sensor 20 and the road surface μ detected by the μ sensor S4.

  In Q4, the target lateral force fx i (i = 1 to 4) and the target longitudinal force fy i (i = 1 to 4) for each tire are determined based on the above-described equation (A). Thereafter, in Q5, the target turning angle and the target slip ratio for each tire are determined by comparing fxi and fyi with the tire model. And in Q6, each control apparatus 10-13 is controlled so that it may become the determined target turning angle and target slip ratio.

  Next, a second embodiment of the present invention will be described. In the present embodiment, the following formula (B) is used instead of the above-described formula (A). The distribution control of the tire force is performed by determining the tire forces Fxi and Fyi of each tire so as to minimize the evaluation function J shown in Equation 2.

J = K1 × (η1 + η2)
+ K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |)
+ K3 × (| η1-η2 | −α) −− (B)

However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K1 = Weighting factor (0 <K1)
K2 = weighting coefficient (0 <K2)
K3 = weighting coefficient (0 <K3)
α = Load factor of a predetermined difference to be set between η1 and η2

  In the above formula (B), the terms K1 and K2 mean the same as in the case of formula (A). In the formula (B), the term K3 is a control that makes the difference between the load factors η1 and η2 of the left and right front tires equal to a predetermined differential load factor α. The differential load factor α can be set to a value of about 10 to 20%, for example. In the formula (B), K1 may be set to 0.

  FIG. 8 is a flowchart showing the third embodiment of the present invention. In the present embodiment, by performing suspension control together, tire force distribution control is performed while changing and controlling the maximum tire force of each tire. Q11 to Q13 in FIG. 8 correspond to Q1 to Q3 in FIG. In Q14 of FIG. 8, although the formula used is formula (A), formula (B) may be used. Further, in the control for minimizing the evaluation function J, the tire force to be determined is to add the ground load fzi (i = 1 to 4) in addition to the lateral force fxi and the longitudinal force fyi. Further, Fzf, Fzr, Fz1, Fz2, Fz3, and Fz4 are used as parameters to be used.

  Fz1 is a load acting on the left front wheel 1FL, Fz2 is a load acting on the right front wheel 1RR, Fz3 is a load acting on the left rear wheel 1RL, and Fz4 is a load acting on the right rear wheel 1RR. Fzf is a load at the front part of the vehicle body and is a value obtained by adding Fz1 and Fz2. Further, Fzr is a load at the rear of the vehicle body, and is a value obtained by adding Fz3 and Fz4. In addition, M is a vehicle body mass and g is a gravitational acceleration.

  Each tire force fxi, fyi, and fzi determined in Q14 is collated with a tire model, and a target turning angle, a target slip ratio, and a target roll / pitch angle are determined. In Q15, the control devices 10 to 14 are controlled so that the target turning angle, the target slip ratio, and the target roll / pitch angle are obtained (suspension control is also executed).

  Although the embodiment has been described above, the present invention is not limited to this, and can be changed as appropriate within the scope of the claims. For example, instead of the load factor η used in the formula (A) or the formula (B), other values related to the load factor, such as tire margin force, may be used. In this case, each formula (A) or In (B), the lateral force fxi and the longitudinal force ffy (or fzi) that minimize the evaluation function J may be determined using the reciprocal of the tire margin force instead of η. Further, the steps or group of steps shown in the flowchart can be grasped as functions of the controller U, and can be expressed by adding the name of “means” to the generic name indicating the functions.

1 is a simplified perspective view showing an example of a vehicle to which the present invention is applied. The figure which shows the example of a control system of this invention in a block diagram. The figure which shows the relationship between the maximum tire force, lateral force, longitudinal force, and tire load factor. The characteristic view which shows the relationship between avoidance steering and the required vehicle responsiveness. The simplified top view which shows the state with the substantially same load factor of each tire. The figure which shows an example of the state from which the load factor of each tire was changed by the control by this invention from the state of FIG. The flowchart which shows the example of control of this invention. The flowchart which shows another example of control of this invention.

Explanation of symbols

VC: Automobile (vehicle)
U: Controller (tire force distribution control device)
10: Steering angle control device 11: Braking force control device 12: Driving force control device 13: Suspension control device 20: Tire force sensor S1: Brake sensor S2: Acceleration sensor S3: Handle sensor S4: Road surface μ sensor fmax: Maximum tire Force fx: lateral force fy: longitudinal force η: load factor J: evaluation function

Claims (10)

A vehicle motion control device capable of changing and controlling the lateral force and the longitudinal force on the front, rear, left and right tires,
Tire force detecting means for detecting the actual tire force of each tire;
Load factor determining means for determining the load factor of each tire based on the tire force detected by the tire force detecting means and the maximum tire force obtained by each tire;
The front / rear / right / left tires are divided into two pairs of tires that are paired with two diagonally located tires, and the tire force of each tire is changed and controlled so that the load factors of the paired tires are equal to each other. Tire force distribution control means;
A vehicle motion control apparatus comprising: In claim 1,
The vehicle motion control device according to claim 1, wherein the tire force distribution control means further controls to change the tire force of each tire so that a load factor of the paired tires is minimized. In claim 1,
The vehicle motion control device according to claim 1, wherein the tire force distribution control means further controls to change the tire force of each tire so that the load factors of the two front left and right tires are minimized. In claim 1,
A vehicle motion control device, wherein the tire force of each tire is changed by changing at least one of a steering angle, a braking force, and a driving force for each tire. In claim 4,
Suspension control means for performing roll control or pitch control of the vehicle body,
The tire force distribution control means further controls the maximum tire force of each tire by controlling the suspension control means;
A vehicle motion control apparatus. In any one of Claims 1 thru | or 5,
The vehicle tire motion control device further controls the front and left tire forces to be different from each other. In claim 1,
The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi to be distributed to each tire so that the evaluation function J based on the following equation (1) is minimized. apparatus.
J = K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |) −− (1)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K2 = Weighting factor (0 <K2) In claim 1,
The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi to be distributed to each tire so that the evaluation function J based on the following equation (2) is minimized. apparatus.
J = K1 × (η1 + η2)
+ K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |) −− (2)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K1 = Weighting factor (0 <K1)
K2 = weighting coefficient (0 <K2) In claim 1,
The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi to be distributed to each tire so that the evaluation function J based on the following equation (3) is minimized. apparatus.
J = K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |)
+ K3 × (| η1-η2 | −α) −− (3)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K2 = Weighting factor (0 <K2)
K3 = weighting coefficient (0 <K3)
α = Load factor of a predetermined difference to be set between η1 and η2 In claim 1,
The tire force distribution control means determines the lateral force fxi and the longitudinal force fyi to be distributed to each tire so that the evaluation function J based on the following equation (4) is minimized. apparatus.
J = K1 × (η1 + η2)
+ K2 × (| 1-η1 / η4 | + | 1-η2 / η3 |)
+ K3 × (| η1-η2 | −α) −− (4)
However,
Fxo = Σfxi (i = 1 to 4), target lateral force at the center of gravity of the vehicle body Fyo = Σfyi (i = 1 to 4), target longitudinal force at the center of gravity of the vehicle body YMo = Σfxi (i = 1 to 2) × Lf + Σfxi (i = 3 to 4) × Lr, target moment Lf = distance between vehicle body center of gravity and front tire Lr = distance between vehicle body center of gravity and rear tire η1 = load ratio of left front tire η2 = load of right front tire Rate η3 = Load factor of left rear tire η4 = Load factor of right rear tire K1 = Weighting factor (0 <K1)
K2 = weighting coefficient (0 <K2)
K3 = weighting coefficient (0 <K3)
α = Load factor of a predetermined difference to be set between η1 and η2

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