JP2006315661A - Driving force distribution device for four-wheel independent driving vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device capable of making a yaw rate and a vehicle lateral acceleration a desired response even if variation of tire lateral force relative to variation of drive force becomes non-linear variation by a lateral slide angle and a wheel load. <P>SOLUTION: The drive force distribution device is provided with a means 8 for determining respective target values of vehicle longitudinal force, vehicle lateral force and yaw moment of the vehicle as vehicle behavior target values; a means 8 for setting a drive force basic value of the respective wheels; a means 8 for performing operation making respective basic values of the vehicle longitudinal force, the vehicle lateral force and the yaw moment realized by the set drive force basic value of the respective wheels as basic values of the vehicle behavior; a means 8 for operating an error of the target value of the vehicle behavior and the operated basic value of the vehicle behavior as an error of the vehicle behavior; a means 8 for operating a drive force correction amount of the respective wheels reducing the operated error of the vehicle behavior; and a means 8 for determining the drive force target value of the respective wheels by sum of the drive force basic value and the operated drive force correction amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a driving force distribution device for a four-wheel independent drive vehicle.

  As a prior art, model following control is known in which a left and right wheel driving force difference is determined by feedforward in a vehicle in which left and right wheels can be driven (or braked) independently, with yaw rate and vehicle lateral acceleration as desired responses. It is described in.

In this model following control, the vehicle is linearized (linear two-wheel model) on the assumption that the steering angle, driving force, side slip angle, etc. of each wheel are sufficiently small, and an inverse model of this linearized vehicle model is obtained. By using the yaw rate and the vehicle lateral acceleration, the difference between the left and right wheels is obtained as a desired response.
Kimio Kanai, Tokumasa Ochi, Taketoshi Kawamata, “Vehicle Control”, Sakai Shoten, January 20, 2004, Chapter 3 Section 3.2

  By the way, according to the technique disclosed in Patent Document 1, a desired yaw rate and vehicle lateral acceleration can be obtained for a linearly approximated vehicle model.

  However, considering the tire lateral force of each wheel that mainly generates yaw rate, lateral acceleration, etc., it is known that the change of the tire lateral force with respect to the driving force changes nonlinearly depending on the side slip angle, wheel load, etc. Yes. In particular, during a sudden turn in which the rudder angle or side slip angle of each wheel is large, a model error due to linear approximation of the rudder angle or side slip angle of each wheel increases.

  Therefore, when the nonlinearity of the tire becomes strong and the model error increases as described above, the yaw rate and the vehicle lateral acceleration are set as desired responses in the difference between the left and right wheel driving forces obtained by the technique of Patent Document 1. This may result in overshoot or convergence delay with respect to the target value, which may impair the driver's maneuverability.

  Therefore, the present invention provides a device that can make yaw rate or vehicle lateral acceleration a desired response even if the change in tire lateral force with respect to the change in driving force becomes a non-linear change due to a side slip angle, wheel load, or the like. For the purpose.

The present invention relates to a target value Fx ** of a vehicle longitudinal force Fx, a target value Fy ** of a vehicle lateral force Fy, and a target value M ** of a yaw moment M in a vehicle capable of independently driving four wheels. Is set as the vehicle behavior target value, and the basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel are set, and the basic driving force value of each wheel thus set is set. Basic value Fx ## of vehicle longitudinal force realized by Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ##, basic value Fy ## of vehicle lateral force, basic value of yaw moment M ## is calculated as the basic value of the vehicle behavior, and the target values Fx **, Fy **, M ** of the vehicle behavior and the calculated basic values Fx ##, Fy ##, M ## of the vehicle behavior are calculated. error between ΔFx, ΔFy, the .DELTA.M calculated as an error of the vehicle behavior, error DerutaFx the computed vehicle behavior, DerutaFy, driving force correction amount DerutaFx ₁ of each wheel to reduce the .DELTA.M, delta x _2, ΔFx _3, calculates the ΔFx _4, wherein the base value _{Fx 1 ##, Fx 2 ##,} Fx 3 ##, Fx 4 ## computed driving force correction amount DerutaFx ₁ of Toko, ΔFx _2, The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** of each wheel are determined by the sum of ΔFx ₃ and ΔFx _4, and the determined driving force target value of each wheel is determined. The driving force of each wheel is controlled so as to obtain Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ **.

Further, according to the present invention, in a vehicle capable of independently driving four wheels, the target value Fx ** of the vehicle longitudinal force and the target value M ** of the yaw moment of the vehicle are determined as the target values of the vehicle behavior. Driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## are set, and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx of the set wheels are set. The basic value Fx ## of the vehicle longitudinal force realized by ₃ ##, Fx ₄ ## and the basic value M ## of the yaw moment are calculated as the basic value of the vehicle behavior, and the target value Fx ** of the vehicle behavior is calculated. Errors ΔFx and ΔM between M ** and the calculated vehicle behavior basic values Fx ## and M ## are calculated as vehicle behavior errors, and the calculated vehicle behavior errors ΔFx and ΔM are reduced. Wheel driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are calculated, and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## and The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each wheel are obtained by adding the calculated driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx _4. The driving force of each wheel is controlled so that the determined driving force target value of each wheel is obtained.

Further, the present invention determines a vehicle longitudinal force target value Fx ** and a vehicle lateral force target value Fy ** as vehicle behavior target values in a vehicle capable of independently driving four wheels. The basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ## and Fx ₄ ## of each wheel are set, and the basic driving force values Fx ₁ ## and Fx ₂ ## of the wheels are set. , Fx ₃ ##, Fx ₄ ##, the vehicle front-rear direction force basic value Fx ## and the vehicle lateral force basic value Fy ## are calculated as vehicle behavior basic values, and the vehicle behavior target value is calculated. Errors ΔFx and ΔFy between Fx ** and Fy ** and the calculated vehicle behavior basic values Fx ## and Fy ## are calculated as vehicle behavior errors, and the calculated vehicle behavior errors ΔFx and ΔM are calculated. the driving force correction amount DerutaFx ₁ of each wheel to reduce, ΔFx _2, ΔFx _3, calculates the ΔFx _4, the driving force basic value _{Fx 1 ##, Fx 2 ##,} Fx 3 ##, F ₄ ## The calculated driving force correction amount DerutaFx ₁ of Toko, ΔFx _2, ΔFx _3, the sum driving force target value Fx ₁ ** of each wheel with _{ΔFx 4, Fx 2 **, Fx} 3 **, Fx ₄ ** is determined, and the driving force of each wheel is controlled so that the determined driving force target value of each wheel is obtained.

In the present invention, the target value Fx ** of the vehicle longitudinal force Fx, the target value Fy ** of the vehicle lateral force Fy, and the target value M ** of the yaw moment M are determined as vehicle behavior target values, and each wheel Driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## are set, and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx of the set wheels are set. The basic value Fx ## of the vehicle longitudinal force realized by ₃ ## and Fx ₄ ##, the basic value Fy ## of the vehicle lateral force, and the basic value M ## of the yaw moment are calculated as the basic values of the vehicle behavior. , Errors ΔFx, ΔFy, ΔM between the vehicle behavior target values Fx **, Fy **, M ** and the calculated vehicle behavior basic values Fx ##, Fy ##, M ## the calculated as an error, error DerutaFx the computed vehicle behavior, DerutaFy, driving force correction amount DerutaFx ₁ of each wheel to reduce ΔM, ΔFx _2, ΔFx _3, calculates the DerutaFx _4, Serial driving force basic value _{Fx 1 ##, Fx 2 ##,} Fx 3 ##, Fx 4 computed driving force of ## Toko correction amount _{ΔFx 1, ΔFx 2, ΔFx 3} , each wheel as the sum of the DerutaFx ₄ Driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** are determined, and the determined driving force target values Fx ₁ **, Fx ₂ **, Fx of each wheel are determined. ₃ **, and configured to control the driving force of each wheel so as Fx ₄ ** is obtained.

  As described above, according to the present invention, each of the target values for the vehicle longitudinal acceleration, the vehicle lateral acceleration, and the yaw angular acceleration is realized while taking into consideration the nonlinear relationship between the driving force and the tire lateral force for each wheel. Since the wheel driving force target value is obtained by feed-forward, the change in the tire lateral force with respect to the driving force change for each wheel may be a non-linear change depending on the side slip angle of each wheel, the wheel load of each wheel, etc. Even in such a case, the desired response can be obtained from the yaw rate or the vehicle lateral acceleration, which improves the driver's maneuverability and makes it impossible to obtain the desired yaw rate or vehicle lateral acceleration. Can be reduced.

In the present invention, in a vehicle capable of independently driving the four wheels, the target value Fx ** of the vehicle longitudinal force and the target value M ** of the yaw moment of the vehicle are determined as target values of the vehicle behavior, and each wheel is determined. Driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## are set, and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx of the set wheels are set. The basic value Fx ## of the vehicle longitudinal force realized by ₃ ##, Fx ₄ ## and the basic value M ## of the yaw moment are calculated as the basic values of the vehicle behavior, and the target value Fx ** of the vehicle behavior is calculated. Errors ΔFx and ΔM between M ** and the calculated vehicle behavior basic values Fx ## and M ## are calculated as vehicle behavior errors, and the calculated vehicle behavior errors ΔFx and ΔM are reduced. The wheel driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are calculated, and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx _{4 of} each wheel are calculated. ## and the calculated driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are the sum of the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ for each wheel. ** is determined, and the driving force of each wheel is controlled so that the determined driving force target value of each wheel is obtained.

Thus, according to the present invention, target values Fx ** and M ** are determined only for the vehicle longitudinal force and yaw moment without setting the target value for the vehicle lateral force, and the two target values Fx. Since the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each wheel that realize ** and M ** are obtained, the vehicle lateral force target value is set to It is no longer necessary to design and hold the target value of the vehicle lateral force in the controller, and the vehicle price can be reduced by reducing the design man-hour and the memory consumption of the in-vehicle computer.

In the present invention, in a vehicle capable of independently driving the four wheels, the vehicle longitudinal force target value Fx ** and the vehicle lateral force target value Fy ** are determined as vehicle behavior target values, The basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ## and Fx ₄ ## of each wheel are set, and the basic driving force values Fx ₁ ## and Fx ₂ ## of the wheels are set. , Fx ₃ ##, Fx ₄ ##, the vehicle front-rear direction force basic value Fx ## and the vehicle lateral force basic value Fy ## are calculated as vehicle behavior basic values, and the vehicle behavior target value is calculated. Errors ΔFx and ΔFy between Fx ** and Fy ** and the calculated vehicle behavior basic values Fx ## and Fy ## are calculated as vehicle behavior errors, and the calculated vehicle behavior errors ΔFx and ΔM are calculated. the driving force correction amount DerutaFx ₁ of each wheel to reduce, ΔFx _2, ΔFx _3, calculates the ΔFx _4, the driving force basic value Fx ₁ # # of each wheel, Fx ₂ ##, Fx ₃ ## Fx ₄ # # to be the operation driving force correction amount _{ΔFx 1, ΔFx 2, ΔFx 3} , the sum driving force target value Fx ₁ ** of each wheel with _{ΔFx 4, Fx 2 **, Fx} 3 **, Fx ₄ ** is determined, and the driving force of each wheel is controlled so that the determined driving force target value of each wheel is obtained.

As described above, according to the present invention, the target values Fx ** and Fy ** are determined only for the vehicle longitudinal force and the vehicle lateral force without setting the target value for the yaw moment, and the two target values Fx are determined. Since the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each wheel that realize ** and Fy ** are obtained, the target value of the yaw moment is designed. Therefore, it is not necessary to hold the target value of yaw moment in the controller, and the vehicle price can be reduced by reducing the design man-hour and the memory consumption of the in-vehicle computer.

  Embodiments of the present invention will be described below.

  FIG. 1 is a schematic configuration diagram of a four-wheel independent drive vehicle of the present embodiment.

  Electric power is supplied from the battery 9 to the motors 11 to 14 via the inverters 31 to 34, and the electric power supplied from the battery 9 causes the motor 11 to move the left front wheel 1, the motor 12 to the right front wheel 2, and the motor 13 to The motor 14 drives the left rear wheel 3 independently or brakes the left rear wheel 3 independently. The battery 9 for supplying power is preferably a nickel metal hydride battery or a lithium ion battery.

  The motors 11 to 14 (actuators that drive or brake the wheels 1 to 4) are AC machines that can perform power running and regenerative operations such as a three-phase synchronous motor and a three-phase induction motor.

  The inverters 31 to 34 convert the alternating current generated by the motors 1 to 4 into a direct current and charge the battery 9, or convert the direct current discharged by the battery 9 into an alternating current and supply it to the motors 1 to 4.

  The rotation radii of the wheels 1 to 4 are all equal to a predetermined value R, and the motors 11 to 14 and the wheels 1 to 4 are directly connected with a reduction ratio of 1, that is, directly. Furthermore, when the wheel load, the side slip angle, and the road surface friction coefficient of each wheel 1 to 4 are the same for the four wheels, the relationship between the braking / driving force and the tire lateral force is the same for the four wheels. That is, all four wheels have the same tire characteristics.

  The front wheels 1 and 2 can be steered by steering the steering 5 via the steering gear 15, and the steering angle is mechanically adjusted via the steering gear 15 by the steering of the steering 5 by the driver. Here, the steering angle change amount of the front wheels 1 and 2 is set to be 1/16 of the steering angle change amount of the steering 5. On the other hand, the steering angle of the rear wheels 3 and 4 is adjusted by the steering actuator 16 so as to follow the command value transmitted from the controller 8.

  A controller 8 comprising a CPU, ROM, RAM, interface circuit, inverter circuit, and the like includes steering speed 5 of each wheel 1 to 4 detected by the wheel speed sensors 21 to 24 and steering 5 by the driver detected by the steering angle sensor 25. , The depression amount of the accelerator pedal 6 detected by the accelerator stroke sensor 26, the depression amount of the brake pedal 7 detected by the brake stroke sensor 27, and the steering angle sensors 41 to 44 (steering angle detecting means). Signals such as the steering angles of the wheels 1 to 4, the lateral acceleration of the vehicle detected by the acceleration sensor 100 attached to the vehicle center of gravity, and the vehicle yaw rate detected by the yaw rate sensor 101 are input to these signals. Torque distribution to each motor 11-14 based on Please is carried out.

  As a conventional technique, model following control is known in which a left-right wheel driving force difference in which a desired response is a yaw rate or lateral acceleration in a vehicle capable of independently driving (or braking) the left and right wheels is determined by feedforward. (Kimio Kanai, Tokumasa Ochi, Taketoshi Kawamata, “Vehicle Control”, Tsubaki Shoten, January 20, 2004, Chapter 3 Section 3.2).

  In this model following control, the vehicle is linearized (linear two-wheel model) on the assumption that the steering angle, driving force, side slip angle, etc. of each wheel are sufficiently small, and the inverse model of this linearized vehicle model is used. Thus, the difference in driving force between the left and right wheels, which makes the desired response to the yaw rate and vehicle lateral acceleration, is obtained. In this prior art, a desired yaw rate and vehicle lateral acceleration can be obtained for a linearly approximated vehicle model.

  However, considering the tire lateral force of each wheel that mainly generates yaw rate, lateral acceleration, etc., it is known that the change of the tire lateral force with respect to the driving force changes nonlinearly depending on the side slip angle, wheel load, etc. Yes. In particular, during a sudden turn in which the steering angle of each wheel or the side slip angle of each wheel is large, a model error due to linear approximation of the steering angle of each wheel or the side slip angle of each wheel increases.

  Therefore, when the tire nonlinearity becomes strong and the model error increases, the difference between the left and right wheel driving force obtained in the prior art cannot make the yaw rate or vehicle lateral acceleration a desired response. , Overshoot or convergence delay may occur with respect to the target value, which may impair the driver's maneuverability.

  Accordingly, the present invention provides a driving force for each wheel that realizes the target values of vehicle longitudinal acceleration, vehicle lateral acceleration, and yaw angular acceleration, while taking into consideration the nonlinear relationship between the driving force and tire lateral force for each wheel. We propose a method for obtaining the distribution by feedforward.

  Hereinafter, the theoretical background of the method proposed by the present applicant and the driving force target value of each wheel that realizes the target values of vehicle longitudinal acceleration, vehicle lateral acceleration, and yaw angular acceleration can be calculated using this theory. Indicates.

  First, the theoretical background of this method will be described with reference to FIG.

  FIG. 2 is a model of the four-wheel independent drive vehicle shown in FIG. That is, in a vehicle capable of independently driving the left front wheel 1, the right front wheel 2, the left rear wheel 3, and the right rear wheel 4, the driving force of each wheel 1-4, the tire lateral force of each wheel 1-4, and each wheel 1 FIG. 6 is a diagram illustrating a longitudinal force acting on the vehicle, a lateral force acting on the vehicle, and a yaw moment around the center of gravity in addition to the steering angle of ˜4.

In FIG. _{2, δ 1, δ 2,} δ 3, δ 4 each wheel 1-4 respectively of the steering angle _{[rad], Fx 1, Fx} 2, Fx 3, Fx 4 in the driving force of each wheel 1-4 [ N], Fy ₁ , Fy ₂ , Fy ₃ , and Fy ₄ are tire lateral forces [N] of the wheels 1 to 4. Further, Fx is a vehicle longitudinal force [N] of the sum of tire forces, Fy is a vehicle lateral force [N] of the sum of tire forces, and M is a yaw around the center of gravity of the vehicle generated by the tire force of each wheel 1-4. The sum of moments [Nm].

Here, the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ and M of each of the wheels 1 to 4 are positive in the clockwise direction when the vehicle is viewed from vertically above, and the steering angles δ ₁ , δ ₂ , δ ₃ and δ ₄ are set to zero when the rotation directions of the wheels 1 to 4 coincide with the vehicle longitudinal direction. Further, the driving forces Fx ₁ , Fx ₂ , Fx ₃ , and Fx ₄ of the wheels 1 to ₄ indicate directions in which the vehicle is accelerated forward when the steering angles δ ₁ , δ ₂ , δ ₃ , and δ ₄ are all zero. Positive, tire lateral forces Fy ₁ , Fy ₂ , Fy ₃ , Fy ₄ of each wheel 1 to 4 accelerate the vehicle to the left when the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ are all zero. The direction to make is positive. For example, if the values of Fx ₁ , Fx ₂ , Fx ₃ , and Fx ₄ are negative, the vehicle is decelerated, and the driving force at this time is a braking force. Therefore, the driving force is used as a concept including a braking force.

The steering angle of each wheel 1 to 4 is δ _i (i = 1 to 4), the driving force of each wheel 1 to 4 is Fx _i (i = 1 to 4), and the tire lateral force of each wheel 1 to 4 is Fy _i (i = 1 to 4), and the integer i attached to the symbols δ, Fx, and Fy is 1 for the left front wheel, 2 for the right front wheel, 3 for the left rear wheel, and 4 for the right rear wheel. It shall be expressed as The integer i attached to the symbol is used in the same meaning for the other symbols.

In FIG. 2, L _f is the distance [m] from the vehicle center of gravity axis to the front wheel axle, L _r is the distance from the vehicle center of gravity axis to the rear wheel axle [m], and L _t is the tread length [m] ]. Therefore, the length L _l [m] of the vehicle wheel base is L _l = L _f + L _r .

Here, first, the vehicle longitudinal force Fx ′ _i (i = 1 to 4) and the vehicle lateral force Fy ′ _i (i) of the resultant force (ie, tire force) of the driving force and the tire lateral force generated in each of the wheels 1 to 4. = 1 to 4). Then, as shown in FIG. 3, the vehicle longitudinal force Fx ′ _i of the tire force and the vehicle lateral force Fy ′ _i of the tire force when the steering angles of the wheels 1 to 4 are cut by δ _i (i = 1 to 4). Is represented by the following equations (1) and (2). However, the vehicle longitudinal force Fx ′ _i of tire force is positive in the direction of accelerating the vehicle forward, and the vehicle lateral force Fy ′ _i of tire force is positive in the direction of accelerating the vehicle in the left direction.

Fx ′ _i = Fx _i cosδ _i −Fy _i sinδ _i (1)
Fy ′ _i = Fx _i sin δ _i + Fy _i cos δ _i (2)
Accordingly, when the tire lateral force change amount when the driving force of each wheel 1 to 4 is changed by a minute amount ΔFx _i (i = 1 to 4) is ΔFy _i (i = 1 to 4), each wheel 1-4 the driving force is small amount DerutaFx _i only vehicle longitudinal direction force Fx of the tire force when changes' _i, vehicle lateral tire force when the driving force of each wheel 1-4 has changed by a minute amount DerutaFx _{i i} 'variation ΔFy of _i' direction force Fy can be expressed by the following equation (3) and (4).

ΔFx ′ _i = ΔFx _i cosδ _i −ΔFy _i sinδ _i (3)
ΔFy ′ _i = ΔFx _i sin δ _i + ΔFy _i cos δ _i (4)
Here, the relationship between the driving force and the tire lateral force for each of the wheels 1 to 4 is as shown in FIG. FIG. 4 is a diagram showing the relationship between the driving force and the tire lateral force when there is no change in the wheel load and the road surface friction coefficient. The driving force is taken on the horizontal axis, and the tire lateral force is taken on the vertical axis. Using the relationship shown in FIG. 4, the current driving force Fx _i (i = 1 to 4) and the tire lateral force Fy _i (i = 1 to 4) of each wheel 1 to 4 with respect to the driving force change ΔFx _i . The sensitivity of the tire lateral force is set to k _i (i = 1 to 4). That is, the sensitivity k _i of the tire lateral force with respect to the driving force change of each wheel 1 to 4 is as shown in FIG. 4 when the vehicle longitudinal force variation ΔFx _i and the vehicle lateral force variation ΔFy _i are very small. This is a value defined by the following equation (5).

k _i = ΔFy _i / ΔFx _i (5)
Then, the change amount DerutaFy _i variation DerutaFx _i and the vehicle lateral force in the vehicle front-rear direction force is very small, the approximation of the equation (5) is sufficiently satisfied, Okeru the ΔFy _i = k _{i ΔFx i,} each The change ΔFx ′ _{i in} the vehicle longitudinal force Fx ′ _i of the tire force and the change in the vehicle lateral force Fy ′ _i of the tire force when the driving force Fx _i of the wheels 1 to 4 changes by a sufficiently small ΔFx _i. The quantity ΔFy ′ _i is transformed into the following expressions (6) and (7).

ΔFx ′ _i = (cosδ _i −k _i sinδ _i ) ΔFx _i = p _i ΔFx _i (6)
ΔFy ′ _i = (sin δ _i + k _i cos δ _i ) ΔFx _i = q _i ΔFx _i (7)
The coefficients p _i and q _i (i = 1 to 4) in the equations (6) and (7) indicate the steering angle δ _i of each wheel 1 to 4 and the side of the tire with respect to the driving force change for each wheel 1 to 4. It is the next value represented by the force sensitivity k _i .

p _i = cosδ _i −k _i sinδ _i (Supplement 1)
_{q i = sinδ i + k i} cosδ i ... ( auxiliary 2)
Here, in the state of FIG. 2, the vehicle front-rear direction force Fx of the sum of tire forces, the vehicle lateral force Fy of the sum of tire forces, and the yaw moment around the center of gravity of the vehicle generated by the tire forces of the wheels 1 to 4. Can be expressed by the following equations (8) to (10). However, the total sum M of the yaw moments around the center of gravity of the vehicle generated by the tire forces of the wheels 1 to 4 is positive in the counterclockwise direction when the vehicle is viewed from above as shown in FIG.

Fx = Fx ′ ₁ + Fx ′ ₂ + Fx ′ ₃ + Fx ′ ₄ (8)
Fy = Fy ′ ₁ + Fy ′ ₂ + Fy ′ ₃ + Fy ′ ₄ (9)
M = {(Fx ′ ₂ + Fx ′ ₄ ) − (Fx ′ ₁ + Fx ′ ₃ )} × L _t / 2.
+ {(Fy ′ ₁ + Fy ′ ₂ ) × L _f − (Fy ′ ₃ + Fy ′ ₄ ) × L _r }
(10)
Therefore, the vehicle of the total tire force when the driving forces Fx ₁ , Fx ₂ , Fx ₃ , and Fx ₄ of the wheels _{1 to 4} change by ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ , which are minute amounts, respectively. The change amounts ΔFx, ΔFy, ΔM of the front-rear direction force Fx, the vehicle lateral force Fy of the sum of tire forces, and the sum M of yaw moments around the center of gravity of the vehicle generated by the tire force of each wheel are expressed by the above formulas (Supplement 1). ) And the coefficients pi and qi of the formula (complement 2) are expressed by the following formulas (11) to (13).

ΔFx = ΔFx ′ ₁ + ΔFx ′ ₂ + ΔFx ′ ₃ + ΔFx ′ ₄ (11)
ΔFy = ΔFy ′ ₁ + ΔFy ′ ₂ + ΔFy ′ ₃ + ΔFy ′ ₄ (12)
ΔM = {(ΔFx ′ ₂ + ΔFx ′ ₄ ) − (ΔFx ′ ₁ + ΔFx ′ ₃ )} × L _t / 2.
+ {(ΔFy ′ ₁ + ΔFy ′ ₂ ) × L _f − (ΔFy ′ ₃ + ΔFy ′ ₄ ) × L _r }
_{= (- p 1 L t /} 2 + q 1 L f) ΔFx 1
+ (P ₂ L _t / 2 + q ₂ L _f ) ΔFx <sub>2
+ (- p 3 L t /</sub> 2-q 3 L r) ΔFx 3
+ (P ₄ L _t / 2-q ₄ L _r ) ΔFx ₄
... (13)
These three expressions (11) to (13) can be summarized by the following determinant (14).

Now, assuming that the driving force correction amount ΔFx ₁ of the left front wheel 1 is known and solving for the driving force correction amounts ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the remaining three wheels 2 to 4, the driving force correction amount of the remaining three wheels 2 to 4 ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ are expressed by the following equation (15).

The coefficients D ₁ , D ₂ , D ₃ , and D _{4 in} Equation (15) are the following values represented by the above-described coefficients p _i and q _i and the wheelbase length L _l .

D ₁ = q ₂ (p ₃ q ₄ −p ₄ q ₃ ) L ₁ + p ₃ (p ₂ q ₄ −p ₄ q ₂ ) L _t (16)
_{D 2 = q 1 (p 4} q 3 -p 3 q 4) L l + p 4 (p 3 q 1 -p 1 q 3) L t ... (17)
D ₃ = q ₄ (p ₂ q ₁ −p ₁ q ₂ ) L ₁ + p ₁ (p ₄ q ₂ −p ₂ q ₄ ) L _t (18)
D ₄ = q ₃ (p ₁ q ₂ −p ₂ q ₁ ) L ₁ + p ₂ (p ₁ q ₃ −p ₃ q ₁ ) L _t (19)
Therefore, from the above equation (15), when the coefficient D ₁ ≠ 0, the vehicle longitudinal force Fx of the total tire force around the current operating point, the vehicle lateral force Fy of the total tire force, and each wheel Driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx for the wheels 1 to 4 that change the sum M of the yaw moment around the center of gravity of the vehicle generated by the tire forces 1 to 4 by ΔFx, ΔFy, ΔM, which are minute amounts, respectively. ₃ and ΔFx ₄ can be obtained by the following equation (20) with χ as an arbitrary constant.

Similarly, when the above equation (14) is solved assuming that any one of the driving force correction amounts ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the remaining three wheels 2 to 4 is known, the coefficient D ₂ ≠ 0, the coefficient When D ₃ ≠ 0 and coefficient D ₄ ≠ 0, the vehicle longitudinal force Fx of the total tire force around the current operating point, the vehicle lateral force Fy of the total tire force, and the tire force of each wheel 1 to 4 The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for the wheels 1 to 4 that change the total sum M of the yaw moments around the center of gravity of the vehicle generated by the above-mentioned amounts by ΔFx, ΔFy, and ΔM, respectively, are obtained. The formula is obtained. As an example, when the above formula (14) is solved with the driving force correction amount ΔFx ₄ of the right rear wheel 4 known, the following formula (21) is obtained.

Next, using these equations (20) and (21), the driving forces Fx ₁ , Fx ₂ , Fx ₃ , Fx ₄ and the tire lateral forces Fy ₁ , Fy ₂ , Fy ₃ , Fy for each wheel 1 to 4. _4. Driving force target for each wheel that realizes the target value Fx ** of the vehicle longitudinal force, the target value Fy ** of the vehicle lateral force, and the target value M ** of the yaw moment, taking into consideration the nonlinear relationship with FIG. A method for obtaining the value by feedforward will be described with reference to FIG.

  There are three vehicle behaviors: a vehicle longitudinal force Fx that is the sum of tire forces, a vehicle lateral force Fy that is the sum of tire forces, and a sum M of yaw moments around the center of gravity of the vehicle that is generated by the tire forces of each wheel 1-4. Since these are uniquely determined, these three Fx, Fy, and M are hereinafter collectively referred to as “vehicle behavior”.

  First, from the driver's accelerator and steering wheel operations, the vehicle longitudinal force target value Fx **, vehicle lateral force target value Fy **, yaw moment target value M **, that is, the vehicle behavior target value, are obtained. Generate. It is assumed that the target value of the vehicle behavior has changed as indicated by a broken line from the top to the third level in FIG. 5, for example. That is, from the top to the third stage in FIG. 5, the target value Fy ** of the vehicle lateral force decreases by a certain amount from the timing t1 to the side where the target value Fx ** of the vehicle longitudinal force decreases by a certain amount. The case where the target value M ** of the yaw moment changes to the side where it increases by a certain amount is shown.

  Here, as the target value Fx ** of the vehicle longitudinal force, the target value Fy ** of the vehicle lateral force, and the target value M ** of the yaw moment, for example, model following control (for model that linearly approximates the vehicle) It is set by applying Kimio Kanai, Tokumasa Ochi, Taketoshi Kawamata, “Vehicle Control”, Tsubaki Shoten, January 20, 2004, Chapter 3, Section 3.2).

Next, each wheel 1 to 4 that substantially realizes the vehicle behavior target values (vehicle longitudinal force target value Fx **, vehicle lateral force target value Fy **, and yaw moment target value M **). The driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, and Fx ₄ ## are calculated. When the target value of the vehicle behavior changes as shown by the broken lines in the upper three stages of FIG. 5, the movements of these driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## Shown are the lower four broken lines in FIG. That is, as shown in the lower four stages in FIG. 5, the basic driving force value Fx ₂ ## of the right front wheel 2 is reduced toward the side where the basic driving force value Fx ₁ ## of the left front wheel 1 becomes smaller from the timing t1. To the increasing side, the driving force basic value Fx ₃ ## of the left rear wheel 3 changes to a decreasing side, and the driving force basic value Fx ₄ ## of the right rear wheel 4 changes to a increasing side by a certain amount. .

And the basic value of the vehicle behavior realized by the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of these wheels 1 to 4 (the basic value Fx of the vehicle longitudinal force) ##, basic value of vehicle lateral force Fy ##, basic value of yaw moment M ##) using a vehicle model that takes into account the non-linear relationship between the driving force of each wheel 1-4 and the tire lateral force Ask.

The basic values of vehicle behavior realized by the basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of these wheels 1 to 4 (the basic value Fx ## of the vehicle longitudinal force) , The basic value Fy ## of the vehicle lateral force, and the basic value M ## of the yaw moment are shown by overlapping the solid line from the top to the third level in FIG. The response of the basic value Fx ## of the vehicle is from the vehicle longitudinal force target value Fx **, and the response of the vehicle lateral force basic value Fy ## is from the vehicle lateral force target value Fy **, the basic value M of the yaw moment. The response of ## is delayed from the yaw moment target value M **.

Therefore, vehicle behavior target values (vehicle longitudinal force target value Fx **, vehicle lateral force target value Fy **, yaw moment target value M **) and the basic driving force of each wheel 1-4. Basic values of vehicle behavior realized by values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## (basic value of vehicle longitudinal force Fx ##, basic value of vehicle lateral force Fy # #, Yaw moment basic value M ##) error (ΔFx, ΔFy, ΔM) is calculated, and the driving force correction amount of each wheel 1 to 4 to compensate for this vehicle behavior error (ΔFx, ΔFy, ΔM) ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ are obtained using the above equations (20) and (21).

Finally, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 are used as the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ## of the wheels 1 to 4. , Fx ₄ ##, that is, the vehicle behavior target value (vehicle longitudinal force target value Fx **, vehicle lateral force target value Fy **, yaw moment target value M * *) The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each of the wheels 1 to 4 that realize *) can be obtained.

Fx ₁ ** = Fx ₁ ## + ΔFx ₁ (Supplement 3a)
Fx ₂ ** = Fx ₂ ## + ΔFx ₂ (Supplement 3b)
Fx ₃ ** = Fx ₃ ## + ΔFx ₃ (Supplement 3c)
Fx ₄ ** = Fx ₄ ## + ΔFx ₄ (Supplement 3d)
When the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of these wheels 1 to ₄ are shown in the lower four stages in FIG. The driving force target value Fx ₁ ** of the left front wheel 1 is based on the driving force basic value Fx ₁ ## of the left front wheel 1, and the driving force target value Fx ₂ ** of the right front wheel 2 is the driving force basic value Fx of the right front wheel 2. _{2 From} ##, the driving force target value Fx ₃ ** of the left rear wheel 3 is based on the driving force basic value Fx ₃ ## of the left rear wheel 3, and the driving force target value Fx ₄ ** of the right front wheel 4 is the right rear wheel. It can be seen from the driving force basic value Fx ₄ ## ₄ that the feed forward control is possible.

  This is the gist of the present invention, and the details of the embodiment will be described based on the above theoretical background.

  This control executed by the controller 8 will be described in detail with reference to the following flowchart.

  FIGS. 6 and 7 are for executing torque distribution control to the motors 1 to 4 and describe operation procedures. It is not executed at regular intervals.

In step 10, the rotational speeds ω ₁ , ω ₂ , ω ₃ , ω ₄ [rad / s] of the wheels 1 to 4 are detected by the wheel speed sensors 21 to 24, respectively, and multiplied by the radius R of the wheels 1 to 4. The wheel speeds V ₁ , V ₂ , V ₃ , and V ₄ [m / s] are obtained, and the vehicle speed V [m / s] is calculated by the following equation (22).

V = (V ₁ + V ₂ + V ₃ + V ₄ ) ÷ 4 (22)
Further, the accelerator stroke sensor 26 depresses the depression amount AP [%] of the accelerator pedal 6, the brake stroke sensor 27 depresses the depression amount BP [%] of the brake pedal 7, and the steering angle sensor 25 rotates the rotation angle θ [rad] of the steering wheel 5. , The longitudinal acceleration αx [m / s ² ] and lateral acceleration αy [m / s ² ] of the vehicle by the acceleration sensor 100, the yaw rate γ [rad / s] by the yaw rate sensor 101, and the steering angle sensors 41 to 44. To detect the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to ₄ , respectively.

Here, the vehicle speed V and the wheel speeds V _{1 to} V ₄ are positive in the vehicle forward direction, the steering rotation θ is positive in the counterclockwise direction, αx is positive in the direction in which the vehicle accelerates forward, and αy is When the vehicle is turning left, the direction from the center of gravity of the vehicle toward the turning center is positive, and γ is positive when the vehicle is viewed from above vertically. As described above, the steering angles δ ₁ , δ ₂ , δ ₃ , and δ ₄ of the wheels 1 to 4 are set to zero when the directions of the wheels 1 to 4 coincide with the longitudinal direction of the vehicle body, and the vehicle is moved vertically upward. A counterclockwise direction is positive when entangled.

In this embodiment, the steering angles δ ₁ and δ ₂ of the front wheels ₁ and ₂ are set to δ ₁ = δ ₂ = θ / 16, and the steering angles δ ₃ and δ ₄ of the rear wheels 3 and ₄ are set to δ ₃ = δ ₄ = 0. And In such a case, it is more preferable that the steering angles of the wheels 1 to 4 can be corrected in consideration of the influence of the suspension such as compliance steer and roll steer. In a vehicle that does not have a steering angle sensor, the steering angle of each wheel 1 to 4 may be obtained from the rotation angle θ of the steering 5.

In step 20, the side slip angles β ₁ , β ₂ , β ₃ , β ₄ [rad] of each wheel 1 to 4 are estimated. The side slip angle (also referred to as slip angle) of each of the wheels 1 to 4 is a slip angle (current slip angle) of a wheel at the present time formed by the traveling direction of the vehicle and the front-rear direction of the tire. There are various estimation methods, but the following method is used here as an example (see Japanese Patent Laid-Open No. 10-329689).

That is, the vehicle body side slip angle β is first estimated from the lateral acceleration αy, the yaw rate γ, and the vehicle speed V read in step 10. Then, the side slip angles β ₁ , β ₂ , β ₃ , β ₄ of each wheel 1 to ₄ are estimated from the vehicle body side slip angle β, the yaw rate γ, the vehicle speed V, and the steering angle θ. Specifically, first, the vehicle body side slip angle β [rad] is calculated by the following equation (Supplement 4).

β = ∫ (Yg / V−γ) dt (Supplement 4)
Note that the lateral acceleration αy is used as the centripetal acceleration Yg in (Supplement 4).

Next, the sideslip angles β ₁ and β ₂ of the front wheels 1 and 2 are calculated by the following formula (Supplement 5), and the sideslip angles β ₃ and β ₄ of the rear wheels 3 and 4 are calculated by the following formula (Supplement 6).

β ₁ = β ₂ = β + θ / Gs−γ × L _f / V (Supplement 5)
β ₃ = β ₄ = β + γ × L _r / V (Supplement 6)
Gs in the equation (Supplement 5) is a gear ratio of the steering gear 15.

The signs of the sideslip angles β ₁ , β ₂ , β ₃ , β ₄ of the wheels 1 to 4 are counterclockwise when the angle from the front-rear direction of the wheels 1 to 4 to the direction of the wheel speed is viewed from above. The case is positive. The sign of the vehicle body side slip angle β is the same as the signs of the side slip angles β ₁ , β ₂ , β ₃ , β ₄ of the wheels 1 to 4.

In Step 20, the wheel loads W ₁ , W ₂ , W ₃ , W ₄ [N] of the respective wheels 1 to 4 are calculated by the following formulas (23) to (26).

W ₁ = mgL _r / 2L ₁ −mhαx / 2L ₁ −mhαy / 2L _t (23)
W ₂ = mgL _r / 2L ₁ −mhαx / 2L ₁ + mhαy / 2L _t (24)
_{W 3 = mgL f / 2L l} + mhαx / 2L l -mhαy / 2L t ... (25)
W ₄ = mgL _f / 2L ₁ + mhαx / 2L ₁ + mhαy / 2L _t (26)
In Expressions (23) to (26), m is the mass of the vehicle [kg], h is the height of the center of gravity of the vehicle [m], and g is the acceleration of gravity [m / s ² ]. As described above, L _r is the distance [m] from the center of gravity of the vehicle in the yaw rotation direction to the rear wheel axle, L _t is the tread length [m] of the front and rear wheels, and L _l is the wheel base length [m]. is there. A calculation method (estimation method) of the wheel loads W ₁ , W ₂ , W ₃ , and W ₄ of each of the wheels 1 to 4 is described in Japanese Patent Application Laid-Open No. 2002-212378, and is obtained according to the official gazette here. Note that a load sensor may be provided to detect the wheel loads W ₁ , W ₂ , W ₃ , and W ₄ of each of the wheels 1 to 4.

Further, in step 20, the road surface friction coefficients μ ₁ , μ ₂ , μ ₃ , μ ₄ [unknown number] of each wheel 1 to 4 are estimated. There are various estimation methods, but here, as an example, the following method (see JP-A-6-98418) is used. In this method, road surface reaction forces F ₁ , F ₂ , F ₃ , and F ₄ received by the wheels 1 to 4 from the road surface are estimated, and the road surface reaction forces F ₁ , F ₂ , F ₃ , and F ₄ and step 20 are performed. The road surface friction coefficients μ ₁ , μ ₂ , μ ₃ , and μ ₄ of each wheel 1 to ₄ are estimated from the obtained wheel loads W ₁ , W ₂ , W ₃ , and W ₄ .

  Briefly, the electromagnetic torque Tm is applied to the motor for one wheel, and the road surface reaction force torque F × R, which is the road surface reaction force F multiplied by the wheel radius R, is applied to the wheel in the opposite direction to the motor torque. To do. And it can be assumed that the motor and the wheel are directly connected, and the torsional rigidity κ of the axle is sufficiently large (ignoring torsional deformation of the axle), and the rotational speed of the motor and the rotational speed of the wheel are the same rotational speed ω. Assuming that the relationship of [rad / s] holds, the equation of motion of the rotating system of the motor and wheels can be summarized as the following equation (Supplement 7).

(Jm + Jw) dω / dt = Tm−Cmw · ω−Rmw · ω−F · R (Supplement 7)
Jm in the formula (Supplement 7) is the moment of inertia of the motor, Jw is the moment of inertia of the wheel, Cmw is the viscous damping constant of the wheel rotation system, and Rmw is the individual friction of the wheel rotation system.

  As a result, the road surface reaction force F can be calculated from the following equation (complement 8) obtained by modifying the above equation (complement 7).

F = {Tm− (Jm + Jw) dω / dt−Cmw · ω−Rmw · ω} / R
... (Supplement 8)
Therefore, the road surface reaction forces F ₁ , F ₂ , F ₃ , and F ₄ for each of the wheels 1 to 4 are calculated by the following formulas (complement 9a) to formula (complement 9d) using this formula (complement 8). .

F ₁ = {Tm− (Jm + Jw) dω ₁ / dt−Cmw · ω ₁ −Rmw · ω ₁ } / R
... (Supplement 9a)
F ₂ = {Tm− (Jm + Jw) dω ₂ / dt−Cmw · ω ₂ −Rmw · ω ₂ } / R
... (Supplement 9b)
F ₃ = {Tm− (Jm + Jw) dω ₃ / dt−Cmw · ω ₃ −Rmw · ω ₃ } / R
... (Supplement 9c)
F ₄ = {Tm− (Jm + Jw) dω ₄ / dt−Cmw · ω ₄ −Rmw · ω ₄ } / R
... (Supplement 9d)
The road surface reaction forces F ₁ , F ₂ , F ₃ , F _{4 of the} wheels 1 to 4 calculated in this way and the wheel loads W ₁ , W ₂ , W ₃ , W _{4 of the} wheels 1 to 4 are The road surface friction coefficients μ ₁ , μ ₂ , μ ₃ and μ ₄ are calculated using the following equations (complement 10a) to equation (complement 10d).

μ ₁ = F ₁ / W ₁ (Supplement 10a)
μ ₂ = F ₂ / W ₂ (Supplement 10b)
μ ₃ = F ₃ / W ₃ (Supplement 10c)
μ ₄ = F ₄ / W ₄ (Supplement 10d)
In step 30, a static target value Fx * of the vehicle longitudinal force is obtained by the following equation (23).

Fx * = Fax * + Fbx * (23)
Fax * [N] in the first term on the right side of Expression (23) is based on the target driving force map corresponding to the depression amount AP of the accelerator pedal 6 and the vehicle speed V, and Fbx * [ N] is obtained by calculating the target braking force corresponding to the depression amount BP of the brake pedal 7 based on the target braking force map. Here, the target driving force map indicates the target driving force corresponding to the depression amount AP of the accelerator pedal 6 and the vehicle speed V, and the target braking force map indicates the target braking force corresponding to the depression amount BP of the brake pedal, respectively. The target driving force Fa * and the target braking force Fb * are set as shown in FIGS. 8 and 9, for example.

  The static target value Fx *, the target driving force Fax *, and the target braking force Fbx * of the vehicle longitudinal force are all positive in the direction in which the vehicle is accelerated forward. Therefore, the target braking force Fbx * is zero or a negative value.

  In step 40, the static target value Fy * of the vehicle lateral force, the static target value Fx * of the vehicle longitudinal force that is the sum of the target driving force and the target braking force, the rotation angle θ of the steering wheel 5, the vehicle The speed V is set based on the vehicle lateral force static target value map. Similarly, the static target value γ * of the yaw rate is set based on the yaw rate static target value map from the static target value Fx * of the vehicle longitudinal force, the rotation angle θ of the steering wheel 5 and the vehicle speed V.

  Here, the vehicle lateral force static target value map is a vehicle lateral force static target value Fy corresponding to the vehicle longitudinal force static target value Fx *, the steering wheel 5 rotation angle θ, and the vehicle speed V. * Is previously stored in the ROM of the controller 8, and the static target value Fy * of the vehicle lateral force is set as shown in FIG. 10, for example. Similarly, the yaw rate static target value map is a controller that calculates the static target value Fx * of the vehicle longitudinal force, the rotation angle θ of the steering wheel 5, and the static target value γ * of the yaw rate corresponding to the vehicle speed V. The static target value γ * of the yaw rate is set as shown in FIG. 11, for example.

  10 and 11, the case where the static target value Fx * of the vehicle longitudinal force is small is shown on the left side, and the case where the static target value Fx * of the vehicle longitudinal force is large is shown on the right side.

  As shown on the left side of each of FIGS. 10 and 11, if the steering rotation angle θ is a positive value and the same, as the vehicle speed V increases, the vehicle lateral force static target value Fy * and the yaw rate become static. If the target target value γ * increases with a positive value and the steering rotation angle θ is the same with a negative value, the vehicle lateral force static target value Fy * increases as the vehicle speed V increases. The static target value γ * of the yaw rate is negative and large. Further, if the vehicle speed V is the same, the vehicle lateral force static target value Fy * and the yaw rate static target value γ * increase with positive values as the steering rotation angle θ increases with positive values. On the other hand, as the steering rotation angle θ increases with a negative value, the vehicle lateral force static target value Fy * and the yaw rate static target value γ * increase with a negative value.

  Further, even when the vehicle speed V and the steering rotation angle θ are the same, under the condition that the rotation angle θ is positive, the static target value Fx * of the vehicle longitudinal force shown on the right side of each of FIGS. 10 and 11 is large. However, both the static target value Fy * of the vehicle lateral force and the static target value γ * of the yaw rate are more positive than when the static target value Fx * of the vehicle longitudinal force shown on the left side of each of FIGS. On the other hand, when the rotational angle θ is negative, when the static target value Fx * of the vehicle longitudinal force shown on the right side of each of FIGS. The static target value Fy * of the vehicle lateral force and the static target value γ * of the yaw rate are both negative and smaller than when the static target value Fx * of the vehicle longitudinal force shown on each left side of FIG. 11 is small. ing.

  In FIG. 10 and FIG. 11, the case where the static target value Fx * of the vehicle longitudinal force is small and the case where the static target value Fx * of the vehicle longitudinal force is large are representative. Actually, the vehicle lateral force static target value map and the yaw rate static target value map corresponding to the number of parameters of the vehicle front-rear direction force static target value Fx * are prepared. For example, if there are a total of 50 parameters from the minimum value to the maximum value of the static target value Fx * of the vehicle longitudinal force, each map has 50 parameters.

  A method for setting the two maps (the vehicle lateral force static target value map and the yaw rate static target value map) will be described together at step 50 described later.

In step 50, the static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * of the driving forces of the wheels 1 to 4 are set as the steering rotation angle θ, the vehicle speed V, and the vehicle longitudinal force. The target value Fx * is set based on the driving force static target value map.

Here, the driving force static target value map is a static target value Fx * of the longitudinal force of the vehicle, the rotation angle θ of the steering wheel 5, and the static of the driving force of each wheel 1-4 corresponding to the vehicle speed V. Target values Fx ₁ *, Fx ₂ *, Fx ₃ *, Fx ₄ * are stored in the ROM of the controller 8 in advance, and the static target values Fx ₁ * of the driving forces of the wheels 1 to 4 are stored. , Fx ₂ *, Fx ₃ *, and Fx ₄ * are set as shown in FIG. 12, for example.

In FIG. 12, when the static target value Fx * of the vehicle longitudinal force is small (slow acceleration), the center row, and when the static target value Fx * of the vehicle longitudinal force is large (rapid acceleration), the right side. Even if the vehicle speed V and the steering rotation angle θ are the same, the case where the static target value Fx * of the vehicle longitudinal force shown in the column on the right side of FIG. The values of the static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * of the driving forces of the wheels 1 to 4 are more positive than when the static target value Fx * of the vehicle longitudinal force shown is smaller. The value is getting bigger.

Further, the case where the static target value Fx * of the vehicle longitudinal force is negative (that is, during braking) is shown in the left column of FIG. 12, and the static target value of the vehicle longitudinal force shown in the left column of FIG. When Fx * is negative, the static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * of the driving forces of the wheels 1 to ₄ are also negative values.

  In FIG. 12, the static target value Fx * of the vehicle longitudinal force is negative, the static target value Fx * of the vehicle longitudinal force is small, and the static target value Fx * of the vehicle longitudinal force. The driving force static target value maps corresponding to the number of parameters of the static target value Fx * of the vehicle longitudinal force are actually prepared. For example, if there are a total of 50 parameters from the minimum value to the maximum value of the static target value Fx * of the vehicle longitudinal force, there are 50 × 4 driving force static target value maps.

  Here, the driving force distribution static target value map, the vehicle lateral force static target value map and the yaw rate static target value map used in step 40 will be described together.

Driving force sum Fx _all [N] of the four wheels 1 to 4, left and right wheel driving force difference ΔFx _all [N], front wheel driving force distribution η [anonymous number], front wheel distribution Δη [anonymous number] of the left and right wheel driving force difference Is defined by the following equations (24) to (27).

Fx _all = Fx ₁ + Fx ₂ + Fx ₃ + Fx ₄ (24)
ΔFx _all = (Fx ₂ + Fx ₄ ) − (Fx ₁ + Fx ₃ ) (25)
η = (Fx ₁ + Fx ₂ ) / Fx _all (26)
Δη = (Fx ₂ −Fx ₁ ) / Fx _all (27)
However, in the present embodiment, the front wheel driving force distribution η and the front wheel distribution Δη of the left and right wheel driving force difference in the equations (26) and (27) are always 0.6 (60% of the distribution to the front wheels 1 and 2). To do.

Then, the driving force sum Fx _all four wheel 1-4 which this vehicle can take, the driving force difference DerutaFx _all, steering 5 of the left and right wheel angle theta, the static target value Fx * 4 one parameter of the front and rear vehicle direction force For all the combinations, the following simulation or experiment is performed to create all of the driving force static target value map, the vehicle lateral force static target value map, and the yaw rate static target value map.

First, one is arbitrarily selected from a combination of the driving force sum Fx _all of the four wheels, the driving force difference ΔFx _all of the left and right wheels, the steering angle θ, and the static target value Fx * of the vehicle longitudinal force. In order to distinguish each of the four selected values from the other, if “′” is added to each of the four values Fx _all , ΔFx _all , θ, Fx *, the selected values are “Fx _all '”, “ΔFx _all ”, respectively. '","Θ'",and" Fx * '".

The driving force values Fx ₁ , Fx ₂ , and Fx _{3 of the} wheels 1 to 4 are calculated from two values (the driving force sum Fx _all ′ and the driving force difference ΔFx _all ′) of the left and right wheels. , Fx ₄ (“Fx ₁ ′”, “Fx ₂ ′”, “Fx ₃ ′”, and “Fx ₄ ′” are added to these as well by adding “′”) to the following equations (28) to (31 ) To set.

Fx ₁ ′ = Fx _all ′ × η / 2−ΔFx _all ′ × Δη / 2 (28)
Fx ₂ '= Fx _all ' × η / 2 + ΔFx _all '× Δη / 2 (29)
Fx ₃ ′ = Fx _all ′ × (1−η) / 2−ΔFx _all ′ × (1−Δη) / 2
... (30)
Fx ₄ ′ = Fx _all ′ × (1−η) / 2 + ΔFx _all ′ × (1−Δη) / 2
... (31)
Further, the steering angle of the front wheels 1 and 2 is set to δ ₁ ′ = δ ₂ ′ = θ ′ / 16 (the steering gear ratio is 1/16) from the selected value θ ′.

The driving force values Fx ₁ ′, Fx ₂ ′, Fx ₃ ′, Fx ₄ ′ thus set and the selected front wheel steering angles δ ₁ ′, δ ₂ ′ (the steering angles δ ₃ , δ of the rear wheels 3, 4). ₄ causes the vehicle to travel in Figure 1 de zero), and -Fx * 'that perform experiments and simulations applied to the vehicle longitudinal direction at the center of gravity of the vehicle position. Then, the vehicle speed V, the vehicle lateral force Fy, and the yaw rate γ when sufficient time has elapsed and the vehicle speed becomes constant (steady state) are obtained. “V”, “Fy ′”, and “γ ′” are added to “V”, “Fy”, and “γ” thus obtained by adding “′”.

By one experiment and simulation, a combination of θ ′, V ′, Fy ′, γ ′, Fx ₁ ′, Fx ₂ ′, Fx ₃ ′, and Fx ₄ ′ representing one state is obtained.

In this way, the vehicle speed V ′, the steering rotation angle θ ′, the vehicle longitudinal force Fx ′, the vehicle lateral force Fy ′, the yaw rate γ ′, the wheel 1 to 1 obtained through the first experiment and simulation are obtained. 4 driving force values Fx ₁ ′, Fx ₂ ′, Fx ₃ ′, Fx ₄ ′, vehicle speed V of steering force static target value map, vehicle lateral force static target value map, yaw rate static target value map, steering Rotation angle θ, vehicle longitudinal force target static value Fx *, vehicle lateral force static target value Fy *, yaw rate static target value γ *, and driving force static targets for each wheel 1 to 4 Set as values Fx ₁ *, Fx ₂ *, Fx ₃ *, Fx ₄ *.

Next, the selected combination is arbitrarily selected from the combinations of the driving force sum Fx _all of the four wheels, the driving force difference ΔFx _all of the left and right wheels, the steering angle θ, and the static target value Fx * of the vehicle longitudinal force. By selecting another different one and performing the second operation similar to the above, θ ′, V ′, Fy ′, γ ′, Fx ₁ ′, Fx ₂ ′, Fx representing the other one state are performed. ₃ ', Fx _4' combinations are obtained. Thus, the vehicle speed V ′, the steering rotation angle θ ′, the vehicle longitudinal force Fx ′, the vehicle lateral force Fy ′, the yaw rate γ ′, the wheel 1 to 1 obtained by performing the second experiment and simulation are obtained. 4 driving force values Fx ₁ ′, Fx ₂ ′, Fx ₃ ′, Fx ₄ ′, vehicle speed V of steering force static target value map, vehicle lateral force static target value map, yaw rate static target value map, steering Rotation angle θ, vehicle longitudinal force target static value Fx *, vehicle lateral force static target value Fy *, yaw rate static target value γ *, and driving force static targets for each wheel 1 to 4 Set as values Fx ₁ *, Fx ₂ *, Fx ₃ *, Fx ₄ *.

Similarly, experiments and simulations are performed one after another on any remaining combination, and θ ′, V ′, Fy ′, γ ′, Fx ₁ ′, Fx ₂ ′, Fx ₃ representing the other one state. As well as obtaining a combination of ', Fx ₄ ', the vehicle speed V ′ obtained in this way, the steering rotation angle θ ′, the vehicle longitudinal force Fx ′, the vehicle lateral force Fy ′, the yaw rate γ ′, The driving force values Fx ₁ ′, Fx ₂ ′, Fx ₃ ′, and Fx ₄ ′ of the wheels 1 to 4 are used as the vehicle speed of the driving force static target value map, the vehicle lateral force static target value map, and the yaw rate static target value map. V, steering rotation angle θ, vehicle front / rear direction force static target value Fx *, vehicle lateral force static target value Fy *, yaw rate static target value γ *, and driving force of each wheel 1-4 The static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * are set.

Thus, the driving force sum Fx _all four wheel 1-4 which this vehicle can take, the driving force difference DerutaFx _all, steering 5 of the left and right wheel angle theta, the static target value Fx * 4 one parameter of the front and rear vehicle direction force By performing simulations or experiments for all the combinations, the setting of the driving force static target value map, the vehicle lateral force static target value map, and the yaw rate static target value map is all completed.

  In addition, when performing an experiment or simulation, it is performed so as to exclude travel resistance elements such as air resistance and rolling resistance, and when executed on the simulation, driving force and tire lateral force for each wheel 1-4. This is done using a vehicle model that fully considers nonlinearity such as the above.

  In step 60, the dynamic target value Fx ** of the vehicle longitudinal force, the dynamic target value Fy ** of the vehicle lateral force, and the dynamic target value γ ** of the yaw rate are distributed to the driving forces of the wheels 1 to 4. Thus, the static target values Fx *, Fy *, and γ * are obtained by performing an annealing process so that the driver's maneuverability is suitable within the range that can be realized by the above. In this embodiment, a second-order lag transfer function is used for the static target value Fx * of the vehicle longitudinal force, and the static target value Fy * of the vehicle lateral force and the static target value γ * of the yaw rate are used. By performing the smoothing process using the first-order lag transfer function, the dynamic target value Fx ** of the vehicle longitudinal force, the dynamic target value Fy ** of the vehicle lateral force, and the dynamic target value of the yaw rate Get γ **. In particular, the response of the vehicle lateral force dynamic target value Fy ** and the yaw rate dynamic target value γ ** is processed so that it can be realized by the tire force of each wheel 1 to 4. Do.

Further, in step 60, the dynamic target value γ ** of the obtained yaw rate is differentiated and multiplied by the yaw inertia moment I [kg · m ² ] of the vehicle to obtain the dynamic target value M ** of the yaw moment. .

In step 70, a static target value Fx of the driving force of each wheel 1-4 are set in step _{50 1 *, Fx 2 *,} Fx 3 *, based on Fx ₄ *, it is determined in 60 in step Driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx of the wheels 1 to 4 that substantially realize the dynamic target values (Fx **, Fy **, γ **) of the vehicle behavior. ₄ ## is obtained by the following equations (32) to (35).

Fx ₁ ## = Fx _all ## × η / 2−ΔFx _all ## × Δη / 2 (32)
Fx ₂ ## = Fx _all ## × η / 2 + ΔFx _all ## × Δη / 2 (33)
Fx ₃ ## = Fx _all ## × (1−η) / 2−ΔFx _all ## × (1−Δη) / 2
... (34)
Fx ₄ ## = Fx _all ## × (1−η) / 2 + ΔFx _all ## × (1−Δη) / 2
... (35)
The front wheel drive force distribution η and the front wheel distribution Δη of the left and right wheel drive force difference in Expression (32) to Expression (35) are η = Δη = 0.6 as described in Step 50.

Further, Fx _all ## in the equations (32) to (35) is a value obtained by performing the smoothing process on the static target value Fx * of the vehicle longitudinal force in step 60 as the dynamic of the vehicle longitudinal force. Fx ₁ * which is the sum of static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * of the driving forces of the wheels 1 to 4 is the same as that for the target value Fx **. This is the value executed for + Fx ₂ * + Fx ₃ * + Fx ₄ *.

In addition, ΔFx _all ## in the equations (32) to (35) is a linear two-wheel model that linearly approximates a vehicle (written by Masato Abe, 2nd edition, “Motion and control of automobiles”, Sankaido Co., Ltd., Heisei Considering the case where the left and right wheel driving force difference ΔFx _all ## is added to April 3, 2015, Chapter 3 Section 3.2.1), the yaw rate response of this linear two-wheel model is the dynamic target value of the yaw rate. Model following control system designed to be γ ** (Kimio Kanai, Toshimasa Ochi, Taketoshi Kawamata, “Vehicle Control”, Tsubaki Shoten, January 20, 2004, Chapter 3 Section 3.2) The following equation (which is used and corrected so as not to cause a deviation between the static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * of the driving forces of the wheels 1 to 4 in a steady state) 36).

ΔFx _all ## = {s ² + (− a ₁₁ −a ₂₂ ) s + (a ₁₁ a ₂₂ −A ₁₂ a ₂₁ )}
/ {B ₂₂ · s + (a ₂₁ b ₁₁ −a ₁₁ b ₂₁ )} × f _r (s)
× {(a ₂₁ b ₁₁ −a ₁₁ b ₂₁ ) θ / 16 + (− a ₁₁ b ₂₂ ) ΔFx _all #}
_{/ {A 11 b 22 -a 12} a 21}
- _{[{b 21 · s + (a} 21 b 11 -a 11 b 21)}
_{/ {B 22 · s + (} - a 11 b 22)} ] × theta / 16
... (36)
F _r (s) in the equation (36) is the smoothing process when the dynamic target value γ ** of the yaw rate is obtained by performing the smoothing process on the static target value γ * of the yaw rate in Step 60. The transfer functions, Kf and Kr, are cornering forces [N / rad] per unit side slip angle when the side slip angles of the front and rear wheels are sufficiently small.

Further, the coefficients a ₁₁ , a ₁₂ , a ₂₁ , a ₂₂ , b ₁₁ , b ₂₁ , b ₂₂ , and ΔFx _all # in the equation (36) are the following values, respectively.

a ₁₁ = − (2 / mV) (K _f + K _r ) (Supplement 4)
a ₁₂ = − (2 / mV ² ) (K _f L _f −K _r L _r ) −1 (Supplement 5)
a ₂₁ = − (2 / I) (K _f L _f −K _r L _r ) (Supplement 6)
a ₂₂ = − (2 / IV) (K _f L _f ² + K _r L _r ² ) (Supplement 7)
b ₁₁ = 2K _f / mV (Supplement 8)
b ₂₁ = 2K _f L _f / I (Supplement 9)
b ₂₂ = L _t / 2I (Supplement 10)
ΔFx _all # = (Fx ₂ * + Fx ₄ *) − (Fx ₁ * + Fx ₃ *) (Supplement 11)
In step 80, the basic values of the vehicle behavior realized by the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to 4 obtained in step 70, that is, the vehicle. The basic value Fx ## of the longitudinal force, the basic value Fy ## of the vehicle lateral force, and the basic value M ## of the yaw moment are obtained by the following equations (37) to (39), respectively.

Fx ## = Fx ₁ ## + Fx ₂ ## + Fx ₃ ## + Fx ₄ ## (37)
Fy ## = Fy ₁ ## + Fy ₂ ## + Fy ₃ ## + Fy ₄ ## (38)
M ## = {(Fx ₂ ## + Fx ₄ ##) − (Fx ₁ ## + Fx ₃ ##)} × L _t / 2.
+ {(Fy ₁ ## + Fy ₂ ##) × L _f − (Fy ₃ ## + Fy ₄ ##) × L _r }
... (39)
Fy ₁ ##, Fy ₂ ##, Fy ₃ ##, Fy ₄ ## in the equation (38) are the driving force basic values Fx ₁ ##, Fx ₂ # of the wheels 1 to 4 in the current vehicle state. The tire lateral force generated when #, Fx ₃ ##, and Fx ₄ ## are applied to the wheels 1 to 4.

The following three methods are shown as setting methods of the tire lateral forces Fy ₁ ##, Fy ₂ ##, Fy ₃ ##, and Fy ₄ ## of the wheels 1 to 4 described above.
<1> Setting method 1 of tire lateral force of each wheel
This is a simple setting method when the difference in wheel load and road surface friction coefficient of each wheel is not taken into account, and it is driven based on the current side slip angles β ₁ , β ₂ , β ₃ , β ₄ of each wheel 1-4. It is set from a tire characteristic map that represents the relationship between force and tire lateral force.

For example, the case of the left front wheel 1 will be described as an example. In the tire characteristic map of the left front wheel 1, the tire characteristic of the left front wheel 1 is set as shown in FIG. That is, FIG. 13 shows six typical slip angles α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ (| α ₁ | <| α ₂ | <| α ₃ | <| Α ₄ | <| α ₅ | <| α ₆ |), the tire characteristics are shown repeatedly, and the absolute value of the skid angle increases from | α ₁ | to | α ₄ | If | α ₅ |, | α ₆ | after the bulge increases, the whole is now contracted. Therefore, Suppose, if slip angle beta ₁ of the left front wheel 1 is a alpha _2, select the upper alpha ₂ of the tire characteristics of the tire characteristic shown in FIG. 13, the left front wheel 1 from the selected tire characteristic The tire lateral force Fy ₁ ## corresponding to the driving force basic value Fx ₁ ## can be set.

Similarly for the remaining three wheels 2 to ₄ , tire characteristics corresponding to the sideslip angles β ₂ , β ₃ and β ₄ of the respective wheels 2 to 4 are prepared in the same manner as in FIG. The tire lateral forces Fy ₂ ##, Fy ₃ ##, Fy ₄ ## corresponding to the force basic values Fx ₂ ##, Fx ₃ ##, Fx ₄ ## Select and set the tire characteristics for the sideslip angles β ₂ , β ₃ , and β ₄ .
<2> Setting method 2 of tire lateral force of each wheel
This is a setting method (invention according to claim 6 or 7) in consideration of the difference in wheel load or road surface friction coefficient of each wheel, and the current side slip angles β ₁ , β ₂ , In addition to β ₃ and β ₄ , the wheel loads W ₁ , W ₂ , W ₃ , W _{4 of the} wheels 1 to 4 obtained in step 20 or the road surface friction coefficients μ ₁ , μ _{2 of} the wheels 1 to 4, Based on μ ₃ and μ ₄ , a tire characteristic map representing the relationship between the driving force and the tire lateral force for each of the wheels 1 to 4 is set.

In the tire characteristic map in this case, the tire characteristics are set for each of the wheels 1 to 4 as shown in FIG. Here again, the case of the left front wheel 1 will be described as an example. FIG. 14 shows the content of the tire characteristic map when the road surface friction coefficient μ ₁ or the wheel load W ₁ of the left front wheel ₁ is small, on the left side. The content of the tire characteristic map when the road surface friction coefficient μ ₁ or the wheel load W _{1 of the} front wheel 1 is large is shown on the right side, and the road surface friction coefficient μ ₁ or the wheel load W ₁ of the left front wheel 1 at that time The tire characteristic map of the left front wheel 1 according to the side slip angle β ₁ of the left front wheel 1 and the basic driving force value Fx ₁ ## of the left front wheel 1 is selected from the tire characteristic map on the selected side. Set the lateral force Fy ₁ ##.

The same applies to the remaining three wheels 2-4. That is, when the road surface friction coefficients μ ₂ , μ ₃ , μ _{4 of} the remaining three wheels 2 to ₄ or the wheel loads W ₂ , W ₃ , W ₄ are small, the content of the tire characteristic map is the same as that on the left side of FIG. In contrast, the road surface friction coefficient μ ₂ , μ ₃ , μ ₄ of the remaining three wheels 2 to ₄ or the wheel load W ₂ , W ₃ , W ₄ is large, and the content of the tire characteristic map is the same as the right side of FIG. Therefore, a tire characteristic map corresponding to the road surface friction coefficients μ ₂ , μ ₃ , μ ₄ or wheel loads W ₂ , W ₃ , W ₄ at that time is selected, and the skid angle β is selected from the tire characteristic map on the selected side. _2, beta _3, and beta _4, the driving force basic value _{Fx 2 ##, Fx 3 ##,} Fx 4 ## and the tire lateral force Fy ₂ # # in accordance with, Fy ₃ ##, Fy ₄ ##, respectively Set.
<3> Setting method 3 of tire lateral force of each wheel
This is a setting method (the invention according to claim 5) in consideration of the difference in the steering angle of each wheel. In the above formulas (37) to (39), the basic driving force of each wheel 1 to 4 Values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ##, this driving force basic value Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## 4 using the tire lateral forces Fy ₁ ##, Fy ₂ ##, Fy ₃ ##, Fy ₄ ## generated when applied to ₄ , that is, the following equations (40a) to (40d), (41a The vehicle longitudinal force Fx ##, the vehicle lateral force Fy ##, and the yaw moment M ## are estimated by using the values obtained by rotationally converting the wheels 1 to 4 by the rudder angle by the formula (40d).

Fx ₁ ## ← Fx ₁ ## cosδ ₁ −Fy ₁ ## sinδ ₁ (40a)
Fx ₂ ## ← Fx ₂ ## cosδ ₂ −Fy ₂ ## sinδ ₂ (40b)
Fx ₃ ## ← Fx ₃ ## cosδ ₃ −Fy ₃ ## sinδ ₃ (40c)
Fx ₄ ## ← Fx ₄ ## cosδ ₄ −Fy ₄ ## sinδ ₄ (40d)
Fy ₁ ## ← Fx ₁ ## sinδ ₁ + Fy ₁ ## cosδ ₁ (41a)
Fy ₂ ## ← Fx ₂ ## sinδ ₂ + Fy ₂ ## cosδ ₂ (41b)
Fy ₃ ## ← Fx ₃ ## sinδ ₃ + Fy ₃ ## cosδ ₃ (41c)
Fy ₄ ## ← Fx ₄ ## sinδ ₄ + Fy ₄ ## cosδ ₄ (41d)
In step 90, the vehicle behavior target value set in step 60 and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to ₄ are realized. Error, that is, an error ΔFx between the dynamic target value Fx ** of the vehicle longitudinal force and the basic value Fx ## of the vehicle longitudinal force, the dynamic target value Fy * of the vehicle lateral force The error ΔFy between * and the basic value Fy ## of the vehicle lateral force, and the error ΔM between the dynamic target value M ** of the yaw moment and the basic value M ## of the yaw moment are expressed by the following equations (42) to ( 44).

ΔFx = Fx ** − Fx ## (42)
ΔFy = Fy ** − Fy ## (43)
ΔM = M **-M ## (44)
In step 100 of FIG. 7, the vehicle longitudinal force error ΔFx, the vehicle lateral force error ΔFy, and the yaw moment error ΔM, that is, the driving force correction amount ΔFx ₁ for each wheel 1-4 that corrects the vehicle behavior error. , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ , vehicle longitudinal force error ΔFx, vehicle lateral force error ΔFy, yaw moment error ΔM, and driving force basic values Fx ₁ ##, Fx of the wheels 1 to 4. ₂ ##, Fx ₃ ##, Fx ₄ ## and the current side slip angles β ₁ , β ₂ , β ₃ , β _{4 of the} wheels 1 to 4 are obtained with reference to the driving force correction amount map.

Here, six methods are shown as methods for calculating the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4.
<4> Calculation method 1 of driving force correction amount of each wheel
This steering angle of each wheel, wheel load, by a simple calculation method that does not consider all the difference in the road surface friction coefficient, said driving force correction amount _{ΔFx 1, ΔFx 2, ΔFx 3} , FIG. 15, for example a DerutaFx ₄ Set as follows.

Here, FIG. 15 shows the contents of the driving force correction amount map. The driving force correction amount map extracts all combinations of driving forces and side slip angles of the wheels 1 to 4 that can be taken by the vehicle. In the combination, the relationship between the vehicle behavior errors ΔFx, ΔFy, ΔM and the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to ₄ is obtained in advance by experiments or simulations. In addition, when calculating | requiring on simulation, the tire characteristic map (that is, tire characteristic map like FIG. 13) used in step 80 is referred based on the set driving force and side slip angle of each wheel 1-4. Then, the tire lateral force of each wheel 1 to 4 is obtained, and the vehicle behavior (vehicle longitudinal force Fx ## before and after the driving force of each wheel 1 to 4 is changed using the above equations (37) to (39). , Change in the vehicle lateral force Fy ##, yaw moment M ##).

  Therefore, when the map is provided in the form as shown in FIG. 15, the map as shown in FIG. 15 is provided for all combinations of the driving force and the side slip angles of the wheels 1 to 4 that can be taken by the vehicle. .

15, the case where the vehicle front-rear direction force error ΔFx is small is shown in the left column, while the case where the vehicle front-rear direction force error ΔFx is large is shown in the right column, and is shown in the left column of FIG. If the vehicle longitudinal force error ΔFy is the same when the vehicle longitudinal force error ΔFx is small, the driving force correction amounts ΔFx ₁ and ΔFx _{2 of the} front wheels 1 and 2 increase as the yaw moment error ΔM increases. Further, the driving force correction amounts ΔFx ₃ and ΔFx _{4 of the} rear wheels 3 and ₄ are small. Further, in the case where the vehicle longitudinal force error ΔFx shown in the left column of FIG. 15 is small, if the yaw moment error ΔM is the same, the larger the vehicle lateral force error ΔFy is, the larger the negative value, The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of FIG. ₄ increase, and as the vehicle lateral force error ΔFy increases with a positive value, the driving force correction amounts of the wheels 1 to 4 increase. ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ are small. Further, when the vehicle front-rear direction force error ΔFx shown in the right column of FIG. 15 is large, the driving force correction of each wheel 1 to 4 is corrected as compared with the case where the vehicle front-rear direction force error ΔFx shown in the left side column of FIG. The range in which the quantities ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ can be increased.

In FIG. 15, two cases, the case where the vehicle longitudinal force error ΔFx is small and the case where the vehicle longitudinal force error ΔFx is large, are representative, but actually, the vehicle longitudinal force error ΔFx is A number of driving force correction amount maps are prepared.
<5> Calculation method 2 of driving force correction amount of each wheel
This is a calculation method (the invention according to claim 5) in consideration of the difference in the steering angle of each wheel, and the steering angles δ ₁ , δ ₂ , δ ₃ , and δ ₄ of each wheel 1 to 4 can be taken. For all the combinations, the relationship between the vehicle behavior errors ΔFx, ΔFy, ΔM and the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to ₄ is obtained in advance through experiments or simulations. And keep it in a map.
<6> Driving power correction amount calculation method 3 for each wheel
This is a calculation method (invention according to claim 6) in consideration of the wheel load difference of each wheel, and the wheel loads W ₁ , W ₂ , W ₃ and W ₄ of each wheel 1 to 4 can be taken. For all the combinations, the relationship between the vehicle behavior errors ΔFx, ΔFy, ΔM and the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to ₄ is obtained in advance through experiments or simulations. And keep it in a map.
<7> Driving power correction amount calculation method 4 for each wheel
This is a calculation method (invention of claim 7) in consideration of the difference in road surface friction coefficient of each wheel, and the road surface friction coefficients μ ₁ , μ ₂ , μ ₃ , μ ₄ of each wheel 1 to 4 are calculated. For all possible combinations, the relationship between the vehicle behavior errors ΔFx, ΔFy, ΔM and the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx _{4 of} each wheel 1 to 4 is previously experimentally or simulated. Find it and map it up.
<8> Calculation method 5 of driving force correction amount of each wheel
The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to 4 are obtained according to the flowchart shown in FIG. 17 (the invention according to claim 3). A method of obtaining the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 according to the flow shown in FIG. 17 will be described later.
<9> Driving force correction amount calculation method 6 for each wheel
The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to 4 are obtained according to the flowchart shown in FIG. 18 (the invention according to claim 4). A method of obtaining the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 according to the flow shown in FIG. 18 will be described later.

In step 110 of FIG. 7, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx _{4 of the} wheels 1 to 4 obtained in step 100 and the wheels 1 to 1 estimated in step 70 of FIG. The sum of four driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## is the driving force target value Fx ₁ **, Fx ₂ **, Fx of each wheel 1 to 4 _{As 3} **, Fx ₄ **, that is, according to the following formula (complement 12a) to formula (complement 12d), the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ ** of the wheels 1 to 4 , Fx ₄ ** is calculated.

Fx ₁ ** = Fx ₁ ## + ΔFx ₁ (Supplement 12a)
Fx ₂ ** = Fx ₂ ## + ΔFx ₂ (Supplement 12b)
Fx ₃ ** = Fx ₃ ## + ΔFx ₃ (Supplement 12c)
Fx ₄ ** = Fx ₄ ## + ΔFx ₄ (Supplement 12d)
In step 120 of FIG. 7, a value obtained by dividing the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each wheel 1 to 4 by the radius R of each wheel 1 to 4 is obtained. Then, control is performed so that the motors 11 to 14 of the wheels 1 to 4 output.

  Here, the effect of this embodiment (1st Embodiment) is demonstrated.

In the present embodiment (the invention described in claim 1), the target value Fx ** of the vehicle longitudinal force Fx, the target value Fy ** of the vehicle lateral force Fy, and the target value M ** of the yaw moment M are determined. The vehicle behavior target value is determined (see step 50 in FIG. 6), and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to ₄ are set (see FIG. 6), and the basic value of the vehicle longitudinal force realized by the set driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to 4 thus set. Fx ##, the basic value Fy ## of the vehicle lateral force, and the basic value M ## of the yaw moment are calculated as basic values of the vehicle behavior (see step 80 in FIG. 6), and the target value Fx ** of the vehicle behavior is calculated. , Fy **, M ** and the calculated vehicle behavior basic values Fx ##, Fy ##, M ##, errors ΔFx, ΔFy, ΔM are calculated as vehicle behavior errors (FIG. 6). Step 90 of FIG. 7), the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the respective wheels 1 to 4 for reducing the calculated vehicle behavior errors ΔFx, ΔFy, ΔM are calculated (see FIG. 7). Step 100), the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## and the calculated driving force correction amounts ΔFx ₁ , ΔFx _{2 of} the wheels 1 to 4. The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** of the wheels 1 to ₄ are determined by the sum of ΔFx ₃ and ΔFx ₄ (see step 110 in FIG. 7). The driving forces of the wheels 1 to 4 are controlled so that the determined driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the respective wheels 1 to ₄ are obtained ( (See step 120 in FIG. 7).

  Thus, according to the present embodiment (the invention described in claim 1), the vehicle longitudinal acceleration, the vehicle lateral acceleration, the non-linear relationship between the driving force and the tire lateral force for each wheel are considered. Since the driving force target value of each wheel that achieves the target value of yaw angular acceleration is obtained by feedforward, the change in the tire lateral force with respect to the driving force change for each wheel is determined by the side slip angle of each wheel and the wheel of each wheel. Even if the load may change nonlinearly, the yaw rate or vehicle lateral acceleration can be set to a desired response. This improves the driver's maneuverability and also improves the desired yaw rate and vehicle lateral acceleration. The discomfort that directional acceleration cannot be obtained can be reduced.

Sensitivity K _ix of the vehicle longitudinal force with respect to changes in the driving force of each wheel 1-4, sensitivity K _iy of vehicle lateral force with respect to changes in the driving force of each wheel 1-4, and changes in driving force of each wheel 1-4 Since the sensitivity K _{iM of the} yaw moment and the vehicle lateral force of the tire force change depending on the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to 4, the steering angles δ ₁ , δ _2, δ _3, δ driving force correction amount DerutaFx ₁ for the wheels 1 to 4 as a ₄ is constant, ΔFx _2, ΔFx _3, than was calculating the DerutaFx _4, the driving force correction amount ΔFx _1, ΔFx ₂ , ΔFx ₃ , ΔFx ₄ , an error occurs, but according to the present embodiment (the invention described in claim 5), the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to ₄ are set. comprising a steering angle sensor 41 to 44 that detects (steering angle detection means), vehicle behavior basic value calculating means, the steering angle [delta] ₁ of the detected each wheel _{was, δ 2, δ 3, δ} 4 based on Basic value Fx # # of vehicle behavior have, Fy # #, calculates the M # #, also driving force correction amount calculating means, the steering angle [delta] ₁ of the respective wheels 1-4 this is detected, [delta] _2, [delta] ₃ , Δ ₄ , the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are calculated, so that the steering angles δ ₁ , δ ₂ , δ ₃ , δ _{4 of the} wheels 1 to ₄ are different. In addition, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 can be accurately obtained.

Sensitivity K _ix of the vehicle longitudinal force with respect to changes in the driving force of the wheels 1 to 4, sensitivity K _iy of vehicle lateral force with respect to changes in the driving force of the wheels 1 to 4, and changes in driving force of the wheels 1 to 4 Since the vehicle lateral force of the tire force that mainly affects the yaw moment sensitivity _KiM and the lateral movement of the vehicle varies depending on the wheel loads W ₁ , W ₂ , W ₃ , and W ₄ of each wheel, If the wheel loads W ₁ , W ₂ , W ₃ and W ₄ of the wheels 1 to ₄ are constant, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ and ΔFx ₄ of the wheels 1 to ₄ are calculated. Although errors occur in the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ , according to the present embodiment (the invention according to claim 6), the wheel loads W _{1 of the} respective wheels 1 to 4. , W ₂ , W ₃ , W ₄ are provided with wheel load estimation / detection means for estimating or detecting the vehicle behavior basic value calculation means. Based on the estimated or detected wheel loads W ₁ , W ₂ , W ₃ , W ₄ of the wheels 1 to ₄ , the vehicle behavior basic values Fx ##, Fy ##, M ## are calculated and driven. Based on the estimated or detected wheel loads W ₁ , W ₂ , W ₃ , W ₄ of the wheels 1 to ₄ , the force correction amount calculation means calculates the driving force correction amounts ΔFx ₁ and ΔFx _{2 of the} wheels 1 to 4. , ΔFx ₃ , ΔFx ₄ are calculated, so that even if the wheel loads W ₁ , W ₂ , W ₃ , W ₄ of the wheels 1 to ₄ are different, the driving force correction amounts ΔFx ₁ , ΔFx _{2 of the} wheels 1 to ₄ are different. , ΔFx ₃ , ΔFx ₄ can be accurately obtained.

Sensitivity K _ix of the vehicle longitudinal force with respect to changes in the driving force of each wheel 1-4, sensitivity K _iy of vehicle lateral force with respect to changes in the driving force of each wheel 1-4, and changes in driving force of each wheel 1-4 Since the vehicle lateral force of the tire force that mainly affects the sensitivity K _{iM of the} yaw moment and the lateral movement of the vehicle varies depending on the road surface friction coefficient μ ₁ , μ ₂ , μ ₃ , μ ₄ of each wheel 1-4, The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to ₄ were calculated on the assumption that the road surface friction coefficients μ ₁ , μ ₂ , μ ₃ and μ ₄ of the wheels 1 to ₄ are constant. Then, an error occurs in the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ , but according to the present embodiment (the invention according to claim 7), the road surface friction of each of the wheels 1 to 4. Road surface friction coefficient estimating means for estimating the coefficients μ ₁ , μ ₂ , μ ₃ , μ ₄ is provided, and the vehicle behavior basic value calculating means Based on the estimated road surface friction coefficient μ ₁ , μ ₂ , μ ₃ , μ ₄ of each wheel 1-4, the vehicle behavior basic values Fx ##, Fy ##, M ## are calculated, and the driving force is corrected. Based on the estimated road surface friction coefficients μ ₁ , μ ₂ , μ ₃ , μ ₄ of the respective wheels 1 to ₄ , the amount calculation means calculates the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx _{3 of the} respective wheels 1 to 4. , ΔFx ₄ is calculated, so that even if the road surface friction coefficients μ ₁ , μ ₂ , μ ₃ , μ ₄ of the wheels 1 to ₄ are different, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx of the wheels 1 to ₄ are different. ₃ and ΔFx ₄ can be accurately obtained.

  FIG. 16 is a flowchart of the second embodiment, which replaces steps 80 to 110 in FIGS. 6 and 7 of the first embodiment.

In FIG. 16, operations in steps 200 and 210 are the same as steps 80 and 90 in FIG. That is, in step 200, the basic value of the vehicle behavior realized by the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 (the basic value of the vehicle longitudinal force). Fx ##, vehicle lateral force basic value Fy ##, yaw moment basic value M ##) are estimated. In step 210, vehicle behavior target value (vehicle longitudinal force dynamic target value Fx **, The vehicle lateral force dynamic target value Fy ** and yaw moment dynamic target value M **) and the vehicle behavior basic value obtained in step 200 (vehicle longitudinal force basic value Fx ##, vehicle Errors ΔFx, ΔFy, ΔM from the basic value Fy ## of the lateral force and the basic value M ## of the yaw moment are obtained.

In step 220, the absolute value | ΔFx | of the vehicle longitudinal force error ΔFx and the absolute value | ΔFy | of the vehicle lateral force error ΔFy are both equal to or less than a predetermined value (for example, 10 [N]) and the yaw moment error. It is checked whether or not the absolute value | ΔM | of ΔM is a predetermined value (for example, 10 [Nm]) or less. The absolute value | ΔFx | of the vehicle longitudinal force error ΔFx and the absolute value | ΔFy | of the vehicle lateral force error ΔFy are both 10 N or less and the absolute value | ΔM | of the yaw moment error ΔM is 10 If it is equal to or less than [Nm], it is determined that the error in the vehicle behavior can be ignored, and the process proceeds to Step 250, where the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ # # Is entered in the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the wheels 1 to 4. That is, Fx ₁ ** = Fx ₁ ##, Fx ₂ ** = Fx ₂ ##, Fx ₃ ** = Fx ₃ ##, Fx ₄ ** = Fx ₄ ## and the flowchart of FIG. Proceed to step 120 in FIG.

On the other hand, if not, the process proceeds from step 220 to step 230, and the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 for correcting the vehicle behavior errors ΔFx, ΔFy, ΔM are obtained.

Here, six methods are shown as methods for calculating the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4. The operation in step 230 is the same as that in step 100 of FIG. 7, and therefore, there are six methods <10> to <15> as follows.
<10> Method 1 for calculating the driving force correction amount of each wheel
This is a calculation method when not considering all the differences in the steering angle, wheel load, and road surface friction coefficient of each wheel, and is the same as the method <4> above.
<11> Calculation method 2 of driving force correction amount of each wheel
This is a calculation method in consideration of the difference in the steering angle of each wheel, and is the same as the method <5> above (the invention according to claim 5).
<12> Calculation method 3 of driving force correction amount of each wheel
This is a calculation method in consideration of the difference in the wheel load of each wheel, and is the same as the method <6> above (the invention according to claim 6).
<13> Calculation method 4 of driving force correction amount of each wheel
This is a calculation method in the case of considering the difference in the road surface friction coefficient of each wheel, and is the same as the method <7> above (the invention according to claim 7).
<14> Calculation method 5 of driving force correction amount of each wheel
The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to 4 are obtained according to the flowchart shown in FIG. 17 (the invention according to claim 3).
<15> Calculation method 6 of driving force correction amount of each wheel
The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to 4 are obtained according to the flowchart shown in FIG. 18 (the invention according to claim 4).

However, in the case of the method <15> described above, that is, when the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 are obtained according to the flow shown in FIG. The coefficients D ₁ , D ₂ , D ₃ , and D ₄ obtained in step S4 are all zero, and in step 800, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels _{1 to 4} are ΔFx ₁ = ΔFx ₂ = When ΔFx ₃ = ΔFx ₄ = 0, the process immediately passes through the flow of FIG. 16 and proceeds to step 120 of FIG.

In step 230, each wheel 1 such that the values νΔFx, νΔFy, νΔM obtained by multiplying the vehicle behavior errors ΔFx, ΔFy, ΔM by a coefficient ν (0 <ν <1) smaller than 1 is zero. Driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of ˜4 may be obtained.

In step 240, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx _{4 of the} wheels 1 to 4 obtained in step 230 and the driving force of the wheels 1 to 4 obtained in step 70 of FIG. By adding the basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ##, the driving force provisional values Fx ₁ ###, Fx ₂ ###, Fx _{3 of} each wheel 1 to 4 ###, Fx ₄ ###, that is, the temporary driving force values Fx ₁ ###, Fx ₂ ###, Fx _{3 of the} wheels 1 to _{4 according} to the following equations (complement 13a) to (complement 13d) ###, Fx ₄ ### are obtained, and in step 250, the driving force provisional values Fx ₁ ###, Fx ₂ ###, Fx ₃ ###, Fx ₄ ### are again obtained for each wheel 1-4. The driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, and Fx ₄ ## are replaced.

Fx ₁ ### ← Fx ₁ ## + ΔFx ₁ , (Supplement 13a)
Fx ₂ ### ← Fx ₂ ## + ΔFx ₂ , (Supplement 13b)
Fx ₃ ### ← Fx ₃ ## + ΔFx ₃ , (Supplement 13c)
Fx ₄ ### ← Fx ₄ ## + ΔFx ₄ , (Supplement 13d)
That is, the provisional value increased by each driving force correction amount is replaced with the basic driving force value of each wheel 1 to 4 and the operation returns to step 200 to execute the operations of steps 200, 210, and 220. If | ΔFx | ≦ 10, | ΔFy | ≦ 10 and | ΔM | ≦ 10 are not satisfied in step 220, the temporary values increased by the respective driving force correction amounts by performing the operations in steps 230, 240, and 250 are renewed. The driving force is reset to the basic driving force value for each of the wheels 1 to 4, and the operation returns to step 200 to execute the operations of steps 200, 210, and 220. In this way, if the driving force basic value of each of the wheels 1 to 4 is increased by each driving force correction amount, | ΔFx | ≦ 10, | ΔFy | ≦ 10 and | ΔM | ≦ 10 in step 220. Since it is established, the routine proceeds to step 260 where the driving force basic value of each wheel 1 to 4 is set as the driving force target value of each wheel 1 to 4. In addition, after proceeding from step 220 to steps 230 to 250, the operations of steps 200 to 220 are performed, and finally the operation of exiting to step 260 is performed in an instant.

As described above, according to the second embodiment (the invention described in claim 2), the driving force target value determining means determines the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx _{4 of the} wheels 1 to _4. And the sum of the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 is the temporary driving force value Fx ₁ ### of each wheel 1 to 4. , Fx ₂ ###, Fx ₃ ###, Fx ₄ ### (step 240 in FIG. 16), and the calculated driving force temporary values Fx ₁ ###, Fx of the respective wheels 1 to 4 are calculated. ₂ ###, Fx ₃ ###, Fx ₄ ### Realized vehicle longitudinal force Fx ###, Vehicle lateral force basic value Fy ###, Yaw moment basic value M # ## is again calculated as the basic value of the vehicle behavior (steps 250 and 200 in FIG. 16), the target values Fx **, Fy **, and M ** of the vehicle behavior and the basic value Fx of the vehicle behavior calculated again. Error with ###, Fy ###, M ### ΔFx #, ΔF #, ΔM # are calculated again as errors in the vehicle behavior (step 210 in FIG. 16), and the driving force correction of each of the wheels 1 to 4 is made to reduce the calculated error ΔFx #, ΔFy #, ΔM # in the vehicle behavior. The amounts ΔFx ₁ #, ΔFx ₂ #, ΔFx ₃ #, ΔFx ₄ # are calculated again (step 230 in FIG. 16), and the driving force temporary values Fx ₁ ###, Fx ₂ ###, Fx ₃ ### , Fx ₄ ### and the recalculated driving force correction amount ΔFx ₁ #, ΔFx ₂ #, ΔFx ₃ #, ΔFx ₄ # for each wheel 1 to 4 is the driving force target for each wheel 1 to 4. Processing for compensating for an error in vehicle behavior is performed by replacing the values as values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** (steps 220 and 260 in FIG. 16). To obtain the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** of the wheels 1 to 4 that realize the target values Fx **, Fy **, M ** of Can With driver maneuverability is improved, thereby reducing the discomfort that can not be obtained a desired yaw rate and the vehicle lateral acceleration.

  Next, the flowchart of FIG. 17 will be described.

This is to obtain the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 for correcting the vehicle behavior errors ΔFx, ΔFy, ΔM by the methods <8> and <14> described above. Is.

In FIG. 17, in step 500, vehicle longitudinal force sensitivities K _1x , K _2x , K _3x , K _4x [anonymous number] and vehicle lateral force sensitivities K _1y , K with respect to changes in driving force for each of the wheels 1 to 4. _2y , K _3y , K _4y [anonymous number], yaw moment sensitivity K _1M , K _2M , K _3M , K _4M [rad · m], the driving force basic values Fx ₁ ##, Fx of each wheel 1 to 4 ₂ ##, Fx ₃ ##, Fx ₄ ## and the current side slip angles β ₁ , β ₂ , β ₃ , β _{4 of} each wheel 1 to 4 are obtained with reference to the vehicle behavior sensitivity map.

  Here, the vehicle behavior sensitivity map is a generic name of three maps, ie, a vehicle longitudinal force sensitivity map, a vehicle lateral force sensitivity map, and a yaw moment sensitivity map, and each wheel 1 to 4 has these three maps. is doing.

This vehicle behavior sensitivity map extracts combinations of all the driving forces of the wheels 1 to 4 and the side slip angle β _{i that} can be taken by the vehicle, and in each combination, the driving force of any one wheel is a minute amount (for example, 1 [N]) A change amount of the vehicle longitudinal force, a change amount of the vehicle lateral force, and a change amount of the yaw moment when changed are obtained and mapped based on each change amount.

Here, the contents of the above three maps for the left front wheel 1 are specifically shown in FIG. 19. The upper part of FIG. 19 shows the sensitivity K _1x of the vehicle longitudinal force with respect to the driving force change for each wheel 1 to 4, FIG. The middle row shows the characteristics of the vehicle lateral force sensitivity K _1y , and the lower row of FIG. 19 shows the yaw moment sensitivity K _1M .

As shown in the upper part of FIG. 19, if the absolute value | β ₁ | of the side slip angle β ₁ of the left front wheel 1 is constant, the vehicle becomes more positive as the driving force basic value Fx ₁ ## of the left front wheel 1 becomes a positive value. The front-rear direction force sensitivity K _1x increases with a positive value. On the other hand, the vehicle front-rear direction force sensitivity K _1x decreases as the driving force basic value Fx ₁ ## of the left front wheel 1 increases with a negative value. It is getting bigger. Further, under the condition that the basic driving force value Fx ₁ ## of the left front wheel 1 is constant, the absolute value of the side slip angle β ₁ of the left front wheel 1 in the region where the basic driving force value Fx ₁ ## of the left front wheel 1 is positive | β _{As the value of 1} | increases, the vehicle front-rear direction force sensitivity K _1x decreases with a positive value. On the other hand, when the basic driving force value Fx ₁ ## of the left front wheel 1 is negative, the side slip angle β ₁ of the left front wheel ₁ As the absolute value | β ₁ | of the vehicle increases, the vehicle longitudinal force sensitivity K _1x decreases with a negative value.

As shown in the middle of FIG. 19, the characteristic of the vehicle lateral force sensitivity K _1y is bilaterally symmetrical. Therefore, if the basic value of the driving force Fx ₁ ## of the left front wheel 1 is added only in a positive region, If the side slip angle β ₁ of the vehicle is constant at a negative value, the vehicle lateral force sensitivity K _1y decreases with a positive value as the driving force basic value Fx ₁ ## of the left front wheel 1 increases. if constant value of sideslip angle beta ₁ positive left front wheel 1, and the sensitivity K _1y enough vehicle lateral force of the driving force basic value Fx ₁ # # left front wheel 1 is increased is reduced by a negative value . Further, under the condition that the driving force basic value Fx ₁ ## of the left front wheel 1 is constant, the vehicle lateral force sensitivity K _1y increases with a positive value as the side slip angle β ₁ of the left front wheel 1 increases with a negative value. , the vehicle lateral force sensitivity K _1y as the side slip angle beta ₁ of the left front wheel 1 is increased in a positive value for this is large in negative value.

As shown in the lower part of FIG. 19, if the absolute value | β ₁ | of the side slip angle β ₁ of the left front wheel 1 is constant, the yaw is increased as the driving force basic value Fx ₁ ## of the left front wheel 1 becomes a positive value. The moment sensitivity K _1M increases with a negative value. On the other hand, the yaw moment sensitivity K _1M increases with a positive value as the driving force basic value Fx ₁ ## of the left front wheel 1 increases with a negative value. . Further, under the condition that the driving force basic value Fx ₁ ## of the left front wheel 1 is constant, the side slip angle β ₁ of the left front wheel ₁ is a positive value in the region where the driving force basic value Fx ₁ ## of the left front wheel ₁ is positive. As the value increases, the sensitivity K _{1M of the} yaw moment decreases with a negative value. On the other hand, when the basic driving force value Fx ₁ ## of the left front wheel 1 is negative, the side slip angle β ₁ of the left front wheel ₁ is a positive value. As the value increases, the sensitivity K _{1M of the} yaw moment decreases with a positive value. Further, under the condition that the basic driving force value Fx ₁ ## of the left front wheel 1 is constant, the side slip angle β ₁ of the left front wheel ₁ is a negative value in the region where the basic driving force value Fx ₁ ## of the left front wheel ₁ is positive. As the value increases, the sensitivity K _{1M of the} yaw moment increases with a negative value. On the other hand, when the basic driving force value Fx ₁ ## of the left front wheel ₁ is negative, the side slip angle β ₁ of the left front wheel ₁ is negative. As the value increases, the sensitivity K _{1M of the} yaw moment increases with a positive value.

In step 510, the vehicle longitudinal force sensitivity K _ix , vehicle lateral force sensitivity K _iy , and yaw moment sensitivity K _iM are expressed as vectors [K _ix K _iy K _iM. ] Is selected as a combination of three wheels that are linearly independent of each other. How to choose is as follows.

First, first consider a matrix K ₁ of the following formula obtained by arranging vectors of the remaining Miwa 2-4 except the left front wheel 1 vertically (61), the matrix K ₁ of the determinant det | if non-zero | K ₁ For example, the combination of the wheels is the remaining three wheels 2, 3 and 4 other than the left front wheel 1, and 1 is set in the flag flg.

If the matrix K ₁ of the determinant det | K ₁ | If zero, turn the matrix K ₂ by arranging the vectors of the remaining Miwa 1,3,4 other than the right front wheel 2 in the vertical of the formula (61) Similarly, if the determinant det | K ₂ | is not zero, the wheel combination is set to the remaining three wheels 1, 3, 4 other than the right front wheel 2, and 2 is set in the flag flg.

Then, the matrix K ₂ of the determinant det | K ₂ | if zero, this time a matrix K ₃ by arranging the vectors of the remaining Miwa 1,2,4 other than the left rear wheel 3 vertically above formula (61) If the determinant det | K ₃ | is not zero, the remaining three wheels 1, 2, 4 other than the left rear wheel 3 are set, and the flag flg is set to 3.

Here, further matrix K ₃ of the determinant det | K ₃ | If zero, the matrix K ₄ of the turn formed by arranging a vector of the remaining Miwa 1,2,3 other than the right rear wheel 4 in the longitudinal formula ( If the determinant det | K ₄ | is not zero, the remaining three wheels 1, 2, 3 other than the right rear wheel 4 are set, and 4 is set in the flag flg.

When the four determinants det | K ₁ |, det | K ₂ |, det | K ₃ |, and det | K ₄ | are all zero, no flag is set and zero is set in the flag flg.

In step 520, the value of the flag flg set in step 510 is checked. When the flag flg = 0, the routine proceeds to step 540, where the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels _{1 to 4} are set to ΔFx ₁ = ΔFx ₂ = ΔFx ₃ = ΔFx ₄ = 0. And

On the other hand, if the flag flg is not 0, the process proceeds from step 520 to step 530, and based on the value of the flag flg set in step 510, the driving force correction amounts ΔFx ₁ and ΔFx _{2 of the} wheels 1 to 4 are set. , ΔFx ₃ , ΔFx ₄ are obtained, and the flow of FIG.

Here, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx _{4 for} the wheels 1 to ₄ are obtained. For example, when the flag flg = 1, the following equation (62) Then, driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to ₄ are obtained.

That is, as shown in the equation (62), the driving force correction amounts ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the _three wheels ₂ , ₃ , ₄ in which the matrix K ₁ selected in step 510 is linearly independent from each other are The behavior error ΔFx, ΔFy, ΔM is obtained by multiplying by the inverse matrix of the matrix K ₁ , and the driving force correction amount ΔFx ₁ of the left front wheel 1 that is not selected is set to zero.

Because the driving force correction amount of each wheel 1 to 4 varies depending on the vehicle longitudinal force sensitivity K _ix , vehicle lateral force sensitivity K _iy , and yaw moment sensitivity K _{iM with} respect to the driving force change for each wheel 1 to 4. The driving force of each wheel 1 to 4 is assumed that the vehicle longitudinal force sensitivity K _ix , the vehicle lateral force sensitivity K _iy , and the yaw moment sensitivity K _iM are constant with respect to the driving force change for each wheel 1 to 4. If the correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are calculated, an error occurs in the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ , but this embodiment (Claim 3). The vehicle longitudinal force sensitivity K _ix , vehicle lateral force sensitivity K _iy , and yaw moment sensitivity K _iM with respect to changes in vehicle behavior. Vehicle behavior change sensitivity calculation hand The provided, driving force correction amount calculating means, the sensitivity of the computed vehicle behavior change _{(K ix, K iy, K} iM) based on the driving force correction amount DerutaFx ₁ of each wheel 1~4, ΔFx _2, Since ΔFx ₃ and ΔFx ₄ are calculated, even if the vehicle longitudinal force sensitivity K _ix , vehicle lateral force sensitivity K _iy , and yaw moment sensitivity K _iM differ with respect to the driving force change for each of the wheels 1 to 4. Thus, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 can be obtained more accurately around the current operating point.

  Next, the flowchart of FIG. 18 will be described.

This is to obtain the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 for correcting the vehicle behavior errors ΔFx, ΔFy, ΔM by the methods <9> and <15> described above. Is.

In FIG. 18, in step 700, tire lateral force sensitivities k ₁ , k ₂ , k ₃ , and k ₄ with respect to changes in driving force for the wheels 1 to ₄ are obtained.

Here, the following three methods are shown as methods for estimating the sensitivity k ₁ , k ₂ , k ₃ , k ₄ of the tire lateral force with respect to the driving force change for each wheel.
<15> Tire lateral force sensitivity estimation method 1
This is a simple estimation method when the difference between the wheel load and the road surface friction coefficient of each wheel is not taken into consideration. The case of the left front wheel 1 will be described as an example. The tire lateral force Fy ₁ ## + dFy ₁ corresponding to the driving force Fx ₁ ## + dFx ₁ of the left front wheel 1 is the current of each wheel 1 to 4 used in step 80. sideslip angle beta _1, beta _2, beta _3, among the beta _4, based on the slip angle beta ₁ of the left front wheel 1, with reference to the tire characteristic map representing the relationship between the driving force and the tire lateral force shown in FIG. 4 The tire lateral force sensitivity k ₁ of the left front wheel 1 is obtained according to the following equation (71).

k ₁ = dFy ₁ / dFx ₁ (71)
The driving force correction amount dFx ₁ [N] (dFx ₁ > 0) of the left front wheel 1 is set to a sufficiently small value as compared with the wheel load that can be taken by the left front wheel 1 of the vehicle, and in this embodiment, 10 [N]. (The driving force correction amounts dFx ₂ , dFx ₃ , and dFx _{4 of the} remaining three wheels 2 to ₄ are also set to 10 [N]). That is, by obtaining the change amount dFy ₁ of the tire lateral force basic value Fy ₁ ## of the left front wheel 1 when the driving force basic value Fx ₁ ## of the left front wheel 1 changes by a minute driving force correction amount dFx ₁ . The tire lateral force sensitivity k ₁ with respect to the change in the driving force when the driving force of the left front wheel 1 is set to the basic value Fx ₁ ## is obtained by the above equation (71).

Similarly, the tire lateral force sensitivities k ₂ , k ₃ , and k ₄ for each of the wheels 2 to 4 are obtained for the remaining three wheels 2 to ₄ .
<16> Tire lateral force sensitivity estimation method 2
This is an estimation method when the difference in wheel load of each wheel is taken into consideration (the invention according to claim 6).

  However, it differs from the method <15> only in the tire characteristic map to be used. That is, a tire characteristic map representing the relationship between the driving force and the tire lateral force is provided for each wheel load for one wheel (for example, two tire characteristic maps are provided for different wheel loads as shown in FIG. 14). Then, a tire characteristic map corresponding to the wheel load at that time is selected, and the sensitivity of the tire lateral force is estimated using the selected tire characteristic map.

Here, the case of the left front wheel 1 will be described as an example. Using the selected tire characteristic map, the left when the driving force basic value Fx ₁ ## of the left front wheel 1 is changed by a minute driving force correction amount dFx ₁ by determining the variation dFy ₁ of the tire lateral force basic value Fy ₁ # # front wheel 1, the sensitivity k ₁ of the tire lateral force with respect to change of the driving force when the driving force of the left front wheel 1 and the basic value Fx ₁ # # Ask for.
<17> Method 3 of estimating tire lateral force sensitivity
This is an estimation method when the difference in road surface friction coefficient of each wheel is taken into consideration (the invention according to claim 7).

  However, it differs from the method <15> only in the tire characteristic map to be used. That is, a tire characteristic map representing the relationship between the driving force and the tire lateral force is provided for each road friction coefficient for one wheel (for example, two tire characteristic maps are provided depending on the road friction coefficient as shown in FIG. 14). The tire characteristic map corresponding to the road surface friction coefficient at that time is selected, and the sensitivity of the tire lateral force is estimated using the selected tire characteristic map.

Here, the case of the left front wheel 1 will be described as an example. Using the selected tire characteristic map, the left when the driving force basic value Fx ₁ ## of the left front wheel 1 is changed by a minute driving force correction amount dFx ₁ by determining the variation dFy ₁ of the tire lateral force basic value Fy ₁ # # front wheel 1, the sensitivity k ₁ of the tire lateral force with respect to change of the driving force when the driving force of the left front wheel 1 and the basic value Fx ₁ # # Ask for.

In step 710, the sensitivity k ₁ of the tire lateral force for each wheel 1-4 are obtained in step 700, k _2, k _3, steering angle [delta] ₁ of the respective wheels 1-4 from k _4, δ _2, δ ₃ , Δ _{4 is set} to zero, and coefficients D ₁ , D ₂ , D ₃ , and D ₄ expressed by the following equations (16a) to (19a) are obtained.

D ₁ = q ₂ (p ₃ q ₄ −p ₄ q ₃ ) L ₁ + p ₃ (p ₂ q ₄ −p ₄ q ₂ ) L _t (16a)
_{D 2 = q 1 (p 4} q 3 -p 3 q 4) L l + p 4 (p 3 q 1 -p 1 q 3) L t ... (17a)
D ₃ = q ₄ (p ₂ q ₁ -p ₁ q ₂ ) L ₁ + p ₁ (p ₄ q ₂ -p ₂ q ₄ ) L _t (18a)
D ₄ = q ₃ (p ₁ q ₂ −p ₂ q ₁ ) L ₁ + p ₂ (p ₁ q ₃ −p ₃ q ₁ ) L _t (19a)
The coefficients p ₁ , p ₂ , p ₃ , p ₄ , q ₁ , q ₂ , q ₃ , and q ₄ in the equations (16a) to (19a) are the following values.

p ₁ = cos δ ₁ −k ₁ sin δ ₁ (Supplement 14a)
p ₂ = cos δ ₂ −k ₂ sin δ ₂ (Supplement 14b)
p ₃ = cosδ ₃ −k ₃ sinδ ₃ (Supplement 14c)
p ₄ = cos δ ₄ −k ₄ sin δ ₄ (Supplement 14d)
q ₁ = sin δ ₁ + k ₁ cos δ ₁ (Supplement 15a)
q ₂ = sin δ ₂ + k ₂ cos δ ₂ (Supplement 15b)
q ₃ = sin δ ₃ + k ₃ cos δ ₃ (Supplement 15c)
q ₄ = sin δ ₄ + k ₄ cos δ ₄ (Supplement 15d)
Here, the expressions (16a) to (19a) are the same as the expressions (16) to (19), and the expressions (14a) to (15d) are the expressions (complement 1) and ( It is the same formula as Supplement 2).

In step 720, the coefficient D ₁ is seen from the _four coefficients D ₁ , D ₂ , D ₃ and D ₄ obtained in step 710. If the coefficient D ₁ ≠ 0, the process proceeds to step 730, and the vehicle behavior error ΔFx using the following equation (20a) with the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to ₄ being zero. , ΔFy, ΔM, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to ₄ are obtained, and the flow of FIG.

Expression (20a) is the same as the above expression (20), that is, the above expression (14) is solved with the driving force correction amount ΔFx ₁ of the left front wheel 2 known.

Here, the arbitrary constant χ in the equation (20a) is set to the following equation (72) so that the sum of squares of the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 is minimized. ).

χ = (D ₁ E ₁ + D ₂ E ₂ + D ₃ E ₃ + D ₄ E ₄ )
/ (D ₁ ² + D ₂ ² + D ₃ ² + D ₄ ² )
... (72)
If the coefficient D ₁ = 0 in step 720, the process proceeds to step 740 and another coefficient D ₄ is seen from the above four coefficients. If this other coefficient D ₄ ≠ 0, the routine proceeds to step 750, where the vehicle behavior is calculated using the following equation (21a) in which the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to ₄ are zero. The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to 4 that compensate for the errors ΔFx, ΔFy, and ΔM are obtained, and the flow of FIG. 18 ends.

The expression (21a) is the same as the expression (21) obtained by solving the above expression (14) with the driving force correction amount ΔFx ₄ of the right rear wheel ₄ as known.

Here, the arbitrary constant χ in the equation (21a) is set so that the sum of squares of the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 is minimized as in Step 730. , A value set by the following equation (73).

χ = (D ₁ G ₁ + D ₂ G ₂ + D ₃ G ₃ + D ₄ G ₄ )
/ (D ₁ ² + D ₂ ² + D ₃ ² + D ₄ ² )
... (73)
If the coefficient D ₄ = 0 in step 740, the process proceeds to step 760 and another coefficient D ₂ is seen. If this other coefficient D ₂ ≠ 0, the routine proceeds to step 770, where the above equation (14) is solved from the equation obtained by knowing the driving force correction amount ΔFx ₂ of the right front wheel ₂ as known, and the vehicle behavior errors ΔFx, ΔFy, The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each of the wheels 1 to 4 that compensate ΔM are obtained, and the flow of FIG. 18 ends. However, the steering angles δ ₁ , δ ₂ , δ ₃ and δ ₄ are zero.

It should be noted that a value corresponding to the arbitrary constant χ in the above equations (20a) and (21a) appears in the equation obtained by solving the driving force correction amount ΔFx ₂ of the right front wheel 2 as known. 20a) and the value corresponding to the arbitrary constant χ in the equation (21a) are the sums of squares of the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 as in Steps 730 and 750. Set to the minimum.

If the coefficient D ₂ = 0 in step 760, the process proceeds to step 780 to see another coefficient D ₃ . If this other coefficient D ₃ ≠ 0, the routine proceeds to step 790, and the vehicle behavior errors ΔFx, ΔFy are derived from the equation obtained by solving the above equation (14) with the driving force correction amount ΔFx ₃ of the left rear wheel 3 known. , ΔM to compensate for the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of each of the wheels 1 to _4, and the flow of FIG. 18 ends. However, the steering angles δ ₁ , δ ₂ , δ ₃ and δ ₄ are zero.

It should be noted that a value corresponding to the arbitrary constant χ in the above equations (20a) and (21a) appears in the equation obtained by solving the driving force correction amount ΔFx ₃ of the left rear wheel 3 as known. The value corresponding to the arbitrary constant χ in (20a) and equation (21a) is the sum of squares of the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of each wheel 1 to 4 as in steps 730 and 750. Is set to be minimum.

If the coefficient D ₃ = 0 in step 780, that is, if the four coefficients D ₁ , D ₂ , D ₃ , and D ₄ are all zero, the process proceeds to step 800, where the driving force correction amounts ΔFx ₁ , The flow of FIG. 18 is ended by setting ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ to ΔFx ₁ = ΔFx ₂ = ΔFx ₃ = ΔFx ₄ = 0.

In step 710, four coefficients D ₁ , D ₂ , D ₃ , D ₄ are obtained by setting the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to ₄ to zero, and steps 730, 750, In 770 and 790, the steering angles δ ₁ , δ ₂ , δ ₃ , and δ ₄ of the wheels 1 to ₄ are set to zero, and the driving force correction amounts ΔFx of the wheels 1 to 4 are compensated for the vehicle behavior errors ΔFx, ΔFy, and ΔM. ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ are obtained. In step 710, the steering angles δ ₁ , δ ₂ , δ ₃ , and δ ₄ of the wheels 1 to ₄ are used as they are without being zero, and the coefficient D ₁ , D ₂ , D ₃ , D ₄ , and are used as they are without making the steering angles δ ₁ , δ ₂ , δ ₃ , δ ₄ of the wheels 1 to 4 zero in steps 730, 750, 770, 790. Thus, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 for compensating for the vehicle behavior errors ΔFx, ΔFy, ΔM are obtained. (The invention according to claim 5).

Since the driving force correction amount of each wheel 1 to 4 varies depending on the sensitivity k ₁ , k ₂ , k ₃ , and k ₄ of the tire lateral force with respect to the driving force change for each wheel 1 to 4, the sensitivity k ₁ , k _2. , K ₃ , k ₄ are constant, and the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to ₄ are calculated, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ , but according to the present embodiment (the invention according to claim 4), the sensitivity of the tire lateral force to the driving force change for each of the wheels 1 to 4, k ₁ , k ₂ , tire lateral force sensitivity estimating means for estimating k ₃ , k ₄ is provided, and the driving force correction amount calculating means is based on the estimated tire lateral force sensitivities k ₁ , k ₂ , k ₃ , k ₄ , respectively. driving force correction amount DerutaFx ₁ ring 1~4, ΔFx _2, ΔFx _3, since the operation of ΔFx _4, for each wheel 1-4 Be different sensitivity of tire lateral force against a power change, the driving force correction amount DerutaFx ₁ of each wheel 1-4 more accurately and conveniently at about the current operating point, ΔFx _2, ΔFx _3, be determined DerutaFx ₄ it can.

  Next, the flowcharts of FIGS. 20 and 21 are the third embodiment, and the flowcharts of FIGS. 24 and 25 are the fourth embodiment, which replace FIGS. 6 and 7 of the first embodiment, respectively. 20, FIG. 21, FIG. 24, and FIG. 25 are also for executing the torque distribution control to the motors 1 to 4, and describe the operation procedure. It is not executed at regular intervals. The same step numbers are assigned to the same parts as those in FIGS.

  In the first and second embodiments, the target values Fx **, Fy **, and M ** are independently set for all of the vehicle longitudinal force Fx, the vehicle lateral force Fy, and the yaw moment M, respectively. However, when considering further, there is a strong dependency between the vehicle lateral force Fy and the yaw moment M, and if one of the responses is determined, the other response is also approximately determined.

  The dependency relationship between the vehicle lateral force Fy and the yaw moment M will be further described. The relationship of the following equation (81) exists between the vehicle yaw rate γ and the centripetal acceleration Yg.

Yg = V × (γ + dβ / dt) (81)
Formula (81) is basically the same as the above formula (complement 4), and the above formula (complement 4) is differentiated with respect to time, and arranged for centripetal acceleration Yg. Therefore, V on the right side of the equation (81) is the vehicle speed, and dβ / dt is a time differential value of the vehicle body side slip angle β.

  From the equation (81), it can be seen that the degree of freedom between the yaw rate γ and the centripetal acceleration Yg is only the vehicle body side slip angle time differential value dβ / dt, and the yaw rate γ and the centripetal acceleration Yg are in a strong dependency.

  The yaw rate γ is a value obtained by dividing the yaw moment M by the yaw moment of inertia of the vehicle, and the centripetal acceleration Yg is substantially equal to the vehicle lateral acceleration when the vehicle body side slip angle β is sufficiently small. This is because the vehicle lateral acceleration αy is included as the centripetal acceleration Yg in the equation (Supplement 4). From this, it can be seen that the vehicle lateral force Fy and the yaw moment M have a strong dependency.

  Therefore, in the third and fourth embodiments, the strong dependency between the vehicle lateral force Fy and the yaw moment M, that is, the response of the vehicle behavior of either the vehicle lateral force Fy or the yaw moment M is determined. For example, the target value is set only for one of the vehicle lateral forces Fy and the yaw moment M using the fact that the other response is almost determined. As a result, according to the third and fourth embodiments, the target value only needs to be set for one of the vehicle behaviors of the vehicle lateral force Fy and the yaw moment M, so the first and second embodiments. Compared to the above, it can be expected that the memory consumption of the in-vehicle computer constituting a part of the controller 8 is reduced and the vehicle price is reduced. In addition, since only one of the target values of the vehicle lateral force Fy and the yaw moment M needs to be designed, a reduction in design man-hours can also be expected.

  The third and fourth embodiments will be described in detail below based on the flowchart.

  From the third embodiment shown in FIGS. 20 and 21 (when only the technology of claim 1 is applied), the differences from the first embodiment will be mainly described. In step 41 of FIG. The static target value γ * is set based on the yaw rate static target value map shown in FIG. 11 from the static target value Fx * of the vehicle longitudinal force, the rotation angle θ of the steering 5 and the vehicle speed V. Here, the vehicle lateral force static target value map is not provided in the controller 8, and the vehicle lateral force static target value Fy * is not set in step 41 of FIG. The purpose of not setting the vehicle lateral force static target value map is to reduce the memory usage of the controller 8 and the calculation load.

  In step 61 of FIG. 20, the driver's maneuverability within a range in which the dynamic target value Fx ** of the vehicle longitudinal force and the dynamic target value γ ** of the yaw rate can be realized by the driving force distribution of the wheels 1 to 4. Is obtained by adding a time delay element to each of the static target values Fx * and γ *. By using the second-order lag transfer function for the static target value Fx * of the vehicle longitudinal force and for the static target value γ * of the yaw rate using the corresponding transfer function, smoothing is performed. A dynamic target value Fx ** for directional force and a dynamic target value γ ** for yaw rate are obtained. In particular, the response of the dynamic target value γ ** of the yaw rate includes a time delay element that can be realized for each driving condition.

  Further, in step 61 of FIG. 20, the dynamic target value of yaw moment is obtained using a transfer function obtained by multiplying the transfer function of the time delay element used for obtaining the dynamic target value γ ** of the yaw rate by a differential element. Find M **.

In step 71 of FIG. 20, based on the static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, Fx ₄ * of the driving forces of the wheels 1 to 4 set in step 50, The driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, and Fx ₄ ## of ₄ are obtained by the following equations (32) to (35) as in the first embodiment.

Fx ₁ ## = Fx _all ## × (η / 2) −ΔFx _all ## × Δη / 2 (32)
Fx ₂ ## = Fx _all ## × (η / 2) −ΔFx _all ## × Δη / 2 (33)
Fx ₃ ## = Fx _all ## × (1−η) / 2−ΔFx _all ## × (1−Δη) / 2
... (34)
Fx ₄ ## = Fx _all ## × (1−η) / 2−ΔFx _all ## × (1−Δη) / 2
... (35)
The front wheel driving force distribution η and the front wheel distribution Δη of the left and right wheel driving force difference in the equations (32) to (35) are η = Δη = 0.6. Further, ΔFx _all ## in the equations (32) to (35) is entered in the static target value Fx * of the vehicle longitudinal force when the dynamic target value Fx ** of the vehicle longitudinal force is obtained in step 61. The time delay element is expressed as Fx ₁ ** + Fx ₂ * which is the sum of the static target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the driving forces of the wheels 1 to 4. * + Fx ₃ ** + Fx ₄ **.

Here, ΔFx _all ## in the equations (32) to (35) is obtained as follows. That is, a linear two-wheel model in which a vehicle is linearly approximated (Masato Abe, 2nd edition, “Automotive motion and control”, Sankaido Co., Ltd., April 10, 2003, Chapter 3 Section 3.2.1 ) to consider the case where joined by left and right wheel driving force difference ΔFx _all ##, the linear two-wheel model of the yaw rate model following control system the response is designed to be dynamic target value gamma ** the yaw rate (Kanai Kimio, Norimasa Ochi, Taketoshi Kawamata, “Vehicle Control”, Tsubaki Shoten, January 20, 2004, Chapter 3, Section 3.2), and the static force of each wheel 1-4 in steady state The target value Fx ₁ *, Fx ₂ *, Fx _{3 *} , and Fx ₄ * is obtained from the following equation (36) corrected so as not to cause a deviation.

ΔFx _all ## = {s ² + (− a ₁₁ −a ₂₂ ) s + (a ₁₁ a ₂₂ −A ₁₂ a ₂₁ )}
/ {B ₂₂ · s + (a ₂₁ b ₁₁ −a ₁₁ b ₂₁ )} × f _r (s)
× {(a ₂₁ b ₁₁ −a ₁₁ b ₂₁ ) θ / 16 + (− a ₁₁ b ₂₂ ) ΔFx _all #}
_{/ {A 11 b 22 -a 12} a 21}
- _{[{b 21 · s + (a} 21 b 11 -a 11 b 21)}
_{/ {B 22 · s + (} - a 11 b 22)} ] × theta / 16
... (36)
F _r (s) in the equation (36) is a transfer function of a temporal delay element that is entered into the static target value γ * of the yaw rate when the dynamic target value γ ** of the yaw rate is obtained in step 61, Kf, Kr [N / rad] is a cornering force per unit side slip angle when the side slip angle of the front and rear wheels is sufficiently small.

Also, the coefficients a ₁₁ , a ₁₂ , a ₂₁ , a ₂₂ , b ₁₁ , b ₂₁ , b ₂₂ , and ΔFx _all # in the equation (36) are the following values, respectively.

a ₁₁ = − (2 / mV) (K _f + K _r ) (Supplement 4)
a ₁₂ = − (2 / mV ² ) (K _f L _f −K _r L _r ) −1 (Supplement 5)
a ₂₁ = − (2 / I) (K _f L _f −K _r L _r ) (Supplement 6)
a ₂₂ = − (2 / IV) (K _f L _f ² + K _r L _r ² ) (Supplement 7)
b ₁₁ = 2K _f / mV (Supplement 8)
b ₂₁ = 2K _f L _f / I (Supplement 9)
b ₂₂ = L _t / 2I (Supplement 10)
ΔFx _all # = (Fx ₂ * + Fx ₄ *) − (Fx ₁ * + Fx ₃ *) (Supplement 11)
In the equations (A4) to (A11), m is a vehicle mass [kg], V is a vehicle speed [m / s], and I is a vehicle yaw inertia moment [kg · m ² ].

As described above, the method of obtaining ΔFx _all ## in the third embodiment is the same as that in the first embodiment.

In step 81 of FIG. 20, the basic values of the vehicle behavior realized by the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to 4 obtained in step 71 are obtained. That is, the basic value Fx ## of the vehicle longitudinal force and the basic value M ## of the yaw moment are obtained by the following equations (37) and (39), respectively.

Fx ## = Fx ₁ ## + Fx ₂ ## + Fx ₃ ## + Fx ₄ ## (37)
M ## = {(Fx ₂ ## + Fx ₄ ##) − (Fx ₁ ## + Fx ₃ ##)} × L _t / 2.
+ {(Fy ₁ ## + Fy ₂ ##) × L _f − (Fy ₃ ## + Fy ₄ ##) × L _r }
... (39)
Unlike the first embodiment, the basic value Fy ## of the vehicle lateral force is not calculated in the third embodiment. Thereby, the calculation load of the controller 8 can be reduced.

In step 91 of FIG. 20, the target value of the vehicle behavior set in step 61 and the basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 are set. The difference between the basic value of the vehicle behavior and the dynamic target value Fx ** of the vehicle longitudinal force and the basic value Fx ## of the vehicle longitudinal force, and the dynamic target value M of the yaw moment. An error ΔM between ** and the basic value M ## of the yaw moment is obtained by the following equations (42) and (44).

ΔFx = Fx ** − Fx ## (42)
ΔM = M **-M ## (44)
In the third embodiment, neither the dynamic target value Fy ** of the vehicle lateral force nor the basic value Fy ## of the vehicle lateral force is obtained, so unlike the first embodiment, the vehicle lateral force As an error ΔFy between the dynamic target value Fy ** and the vehicle lateral force basic value Fy ##, zero is set as in the following equation (82).

ΔFy = 0 (82)
In step 111 of FIG. 21, the driving force recorrection amounts ∂Fx ₁ , ∂Fx ₂ , ∂Fx ₃ , and ∂Fx ₄ of each wheel 1 to ₄ are obtained, and in step 112, the driving force recorrection of each wheel 1 to ₄ is obtained. The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx _{4 of the} wheels 1 to 4 for which the amounts ∂Fx ₁ , ∂Fx ₂ , ∂Fx ₃ , and ∂Fx ₄ are obtained in step 110. The value added to ** is changed to the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** for each of the wheels 1 to 4, that is, the following formulas (83a) to (83d): ), The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the wheels 1 to ₄ are reset.

Fx ₁ ** ← Fx ₁ ** + ∂Fx ₁ (83a)
Fx ₂ ** ← Fx ₂ ** + ∂Fx ₂ (83b)
Fx ₃ ** ← Fx ₃ ** + ∂Fx ₃ (83c)
Fx ₄ ** ← Fx ₄ ** + ∂Fx ₄ (83d)
Here, how to obtain the driving force recorrection amounts ∂Fx ₁ , ∂Fx ₂ , ∂Fx ₃ , and ∂Fx ₄ for each of the wheels 1 to 4 will be described with reference to the flow of FIG. 22 (the subroutine of step 111 in FIG. 21). .

In FIG. 22, in step 3010, the error ΔFx between the dynamic target value Fx ** of the vehicle longitudinal force and the basic value Fx ## of the vehicle longitudinal force is zero, and the error ΔFy of the vehicle lateral force is a predetermined amount ∂Fy. The error ΔM between the dynamic target value M ** of the yaw moment and the basic value M ## of the yaw moment is set to zero, and each of the wheels 1 to 4 that realizes ΔFx = 0, ΔFy = ∂Fy, ΔM = 0. Driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are obtained using the same processing as in step 100 of FIG. 21, and the obtained driving force correction values ΔFx ₁ , ΔFx ₂ , ΔFx _{3 of} the respective wheels 1 to 4 are obtained. , ΔFx ₄ are set as driving force recorrection amounts ∂∂Fx ₁ , ∂∂Fx ₂ , ∂∂Fx ₃ , ∂∂Fx ₄ for each wheel 1 to ₄ as in the following equations (84a) to (84d). .

∂∂Fx ₁ = ΔFx ₁ (84a)
∂∂Fx ₂ = ΔFx ₂ (84b)
∂∂Fx ₃ = ΔFx ₃ (84c)
∂∂Fx ₄ = ΔFx ₄ (84d)
However, at this time, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 are the driving force target values Fx ₁ **, Fx ₂ **, and Fx ₃ * of the wheels 1 to 4, respectively. *, Fx ₄ ** is obtained by referring to each driving force correction amount map. In addition, when the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of each wheel 1 to 4 are obtained based on the flowchart of FIG. By referring to the vehicle behavior sensitivity map from Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ **, the vehicle longitudinal force, vehicle lateral force, yaw moment with respect to the driving force change of each wheel 1-4 The respective sensitivities K _ix , K _iy and K _iM are obtained. When the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each wheel 1 to 4 are obtained based on the flowchart of FIG. The tire lateral force sensitivities k ₁ , k ₂ , k ₃ , and k ₄ to the driving force changes of the wheels 1 to 4 in Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** are obtained. To do.

In step 3020, the driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ [N] of each wheel 1 to 4 and the driving force minimum value [N] of each wheel 1 to 4 are set. As a setting method of the driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ of each wheel 1 to ₄ and the driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , Fmin ₄ of each wheel 1 to 4, Three methods are shown.
<18> Setting method 1 for maximum / minimum driving force of each wheel
The upper limit of driving force Fdmax ₁ , Fdmax ₂ , Fdmax ₃ , Fdmax ₄ [N] of each wheel 1 to 4 so that the motors 11 to 14 are not overheated and broken so that the motors 11 to 14 are not overheated and broken. Driving power lower limit Fdmin ₁ , Fdmim ₂ , Fdmim ₃ , Fdmin ₄ [N] of each wheel 1 to 4 is obtained, and driving power upper limit Fdmax ₁ , Fdmax ₂ , Fdmax ₃ , Fdmax ₄ of each wheel 1 to 4 is obtained. As the driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ of the wheels 1 to 4, and the driving force lower limits Fdmin ₁ , Fdmim ₂ , Fdmim ₃ , Fdmin ₄ of the other wheels 1 to ₄ , respectively. The driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , and Fmin ₄ of the wheels 1 to ₄ are set.

The driving force upper limits Fdmax ₁ , Fdmax ₂ , Fdmax ₃ , Fdmax ₄ and driving force lower limits Fdmin ₁ , Fdmim ₂ , Fdmim ₃ , Fdmin ₄ are the current temperatures T ₁ , T ₂ , T _{3 of the} motors 11 to 14. , T ₄ , the maximum output Ptmax ₁ , Ptmax ₂ , Ptmax ₃ , Ptmax of each of the motors 11 to 14 is referred to with reference to a map in which the relationship between the motor temperature and the maximum output Ptmax [W] that can suppress the motor overheating is obtained. ₄ [W] is obtained, and using the maximum output Ptmax and the rotational speeds ω ₁ , ω ₂ , ω ₃ , ω _{4 of the} wheels 1 to 4 detected in step 10, the following formula (85a) to It calculates | requires according to Formula (85d) and Formula (86a)-Formula (86d).

Fdmax ₁ = Ptmax ₁ ÷ ω ₁ (85a)
Fdmax ₂ = Ptmax ₂ ÷ ω ₂ (85b)
Fdmax ₃ = Ptmax ₃ ÷ ω ₃ (85c)
Fdmax ₄ = Ptmax ₄ ÷ ω ₄ (85d)
Fdmin ₁ = −Ptmax ₁ ÷ ω ₁ (86a)
Fdmin ₂ = −Ptmax ₂ ÷ ω ₂ (86b)
Fdmin ₃ = −Ptmax ₃ ÷ ω ₃ (86c)
Fdmin ₄ = −Ptmax ₄ ÷ ω ₄ (86d)
As a map for obtaining the relationship between the motor temperature and the maximum output Ptmax capable of suppressing the motor overheating, for example, a map as shown in FIG. 23 is set. Each of the motors 11 to 14 is provided with a sensor (not shown) for detecting the temperature, and the motor temperature T ₁ , T ₂ , T ₃ , T ₄ detected by each sensor is input to the controller 8. To.

Here, if the vehicle is capable of cooperatively controlling the braking force by the mechanical brake of each wheel 1 to 4 and the driving force of each motor 11 to 14, the driving force lower limit Fdmin ₁ , Fdmim ₂ , and Fdmim _{3 for} each wheel 1 to 4. , Fdmin ₄ is added with the maximum braking force of the mechanical brake of each wheel 1-4.
<19> Setting method 2 for maximum / minimum driving force of each wheel
Driving force upper limit Fsmax ₁ , Fsmax ₂ , Fsmax ₃ , Fsmax ₄ [N] of each wheel 1 to 4 that does not cause slip or wheel lock, and driving force lower limit Fsmin ₁ of each wheel 1 to 4 that does not cause slip or wheel lock , Fsmin ₂ , Fsmin ₃ , Fsmin ₄ [N], and the driving force upper limit Fsmax ₁ , Fsmax ₂ , Fsmax ₃ , Fsmax ₄ of each wheel 1 to 4 is determined as the maximum driving force value Fmax of each wheel 1 to 4. ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ , and another driving force lower limit Fsmin ₁ , Fsmin ₂ , Fsmin ₃ , Fsmin ₄ of each of the wheels 1 to 4 is set to the minimum driving force value Fmin ₁ , of each wheel 1 to 4. Set as Fmin ₂ , Fmin ₃ , Fmin ₄ .

The method for obtaining the driving force upper limits Fsmax ₁ , Fsmax ₂ , Fsmax ₃ , Fsmax ₄ and the driving force lower limits Fsmin ₁ , Fsmin ₂ , Fsmin ₃ , Fsmin ₄ is as follows, for example. Using the method described in JP-A-6-98418, the wheels 1 to 4 to estimate the reaction force _{F 1, F 2, F 3} , F 4 which receives from the road surface, the reaction force F ₁ which is the estimated, F ₂ , F ₃ , and F ₄ are used to obtain the following equations (87a) to (87d) and equations (88a) to (88d).

Fsmax ₁ = F ₁ (87a)
Fsmax ₂ = F ₂ (87b)
Fsmax ₃ = F ₃ (87c)
Fsmax ₄ = F ₄ (87d)
Fsmin ₁ = −F ₁ (88a)
Fsmin ₂ = −F ₂ (88b)
Fsmin ₃ = −F ₃ (88c)
Fsmin ₄ = −F ₄ (88d)
<20> Setting method 3 for maximum / minimum driving force of each wheel
Driving force upper limit Fsmax ₁ , Fsmax ₂ , Fsmax ₃ , Fsmax _{4 of} each wheel 1 to 4 obtained by <19> above, and driving force upper limit Fdmax ₁ , Fdmax _{2 of} each wheel 1 to 4 obtained by <18> above. , Fdmax ₃ , Fdmax ₄ are compared, and the smaller value is set as the driving force maximum value Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ of each of the wheels 1 to 4, and each wheel obtained by the above <19> The driving force lower limits Fsmin ₁ , Fsmin ₂ , Fsmin ₃ , and Fsmin _{4 of 1 to 4} are compared with the driving force lower limits Fdmin ₁ , Fdmim ₂ , Fdmim ₃ , and Fdmin _{4 of} each wheel 1 to 4 obtained by the above <18>. Then, the larger value is set as the driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , and Fmin ₄ of the wheels 1 to 4.

  This concludes the description of the three methods for setting the driving force maximum value / minimum value of each of the wheels 1 to 4.

In step 3030, when the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the wheels 1 to ₄ are output, the driving force margin Fmx of the wheels 1 to ₄ is output. ₁ , Fmx ₂ , Fmx ₃ , Fmx ₄ are set. Next, two methods are shown as a method of setting the driving force margin for each of the wheels 1 to 4.
<21> Setting method 1 of driving force margin for each wheel
The driving force margins Fmx ₁ , Fmx ₂ , Fmx ₃ , and Fmx ₄ of the wheels 1 to 4 are set to a sufficiently small value as compared with the maximum driving force that can be output from the wheels 1 to 4. As this sufficiently small value, for example, 200 [N] is set.
<22> Setting method 2 for driving force margin for each wheel
This is a setting method (invention according to claim 11) for setting a driving force margin for each of the wheels 1 to 4 with a variable value corresponding to a driving force maximum value or a driving force minimum value, and is set in step 3020. The driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ of each wheel 1 to ₄ and the driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , Fmin ₄ of each wheel 1 to ₄ , and each wheel From the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of 1 to 4, the driving force margin Fmx ₁ , Fmx ₂ , Fmx ₃ , Fmx of each wheel 1 to 4 is obtained. _{4 is obtained according} to the following equations (89a) to (89d) and equations (90a) to (90d).

[1] _{∂∂Fx 1 ≧ 0, ∂∂Fx 2 ≧} 0, ∂∂Fx 3 ≧ 0, when the _{∂∂Fx 4 ≧ 0 Fmx 1 = Fmax} 1 -Fx 1 ** ... (89a)
Fmx ₂ = Fmax ₂ -Fx ₂ ** (89b)
Fmx ₃ = Fmax ₃ -Fx ₃ ** (89c)
Fmx ₄ = Fmax ₄ -Fx ₄ ** (89d)
[2] When ∂∂Fx ₁ <0, ∂∂Fx ₂ <0, ∂∂Fx ₃ <0, ∂∂Fx ₄ <0 Fmx ₁ = Fx ₁ ** − Fmin ₁ (90a)
Fmx ₂ = Fx ₂ ** − Fmin ₂ (90b)
Fmx ₃ = Fx ₃ ** − Fmin ₃ (90c)
Fmx ₄ = Fx ₄ ** − Fmin ₄ (90d)
This concludes the description of the two methods for setting the driving force margin for each of the wheels 1 to 4.

In step 3040, by using the driving force margin _{Fmx 1, Fmx 2, Fmx 3} , Fmx 4 of the wheels 1 to 4 are set in this manner, the error of a predetermined amount ∂Fy for vehicle lateral force A ratio Ψ [anonymous number] of how much ΔFy can be corrected is obtained according to the following equation (91).

Ψ = min (Fmx ₁ / ∂∂Fx ₁ , Fmx ₂ / ∂∂Fx ₂ , Fmx ₃ / ∂∂Fx ₃ ,
Fmx ₄ / ∂∂Fx ₄ )
... (91)
Formula (91) is a value obtained by dividing the driving force margin for each wheel 1 to 4 by the driving force recorrection amount (that is, Fmx ₁ / ∂∂Fx ₁ , Fmx ₂ / ∂∂Fx ₂ , Fmx ₃ / ∂∂Fx _3). , Fmx ₄ / ∂∂Fx ₄ )).

In step 3050, a value obtained by multiplying the predetermined amount ∂Fy by this ratio ψ is replaced as an error ΔFy regarding the vehicle lateral force, and each wheel 1 that realizes ΔFx = 0, ΔFy = ψ × ∂Fy, ΔM = 0 again. ˜4 driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are obtained by using the same process as in Step 100 of FIG. 21, and the obtained driving force correction amounts ΔFx ₁ , ΔFx _{2 of} the respective wheels 1 to 4 are obtained. , ΔFx ₃ , ΔFx ₄ are set as driving force re-correction amounts ∂Fx ₁ , ∂Fx ₂ , ∂Fx ₃ , ∂Fx ₄ for each wheel 1 to ₄ as in the following formulas (92a) to (92d). .

∂Fx ₁ = ΔFx ₁ (92a)
∂Fx ₂ = ΔFx ₂ (92b)
∂Fx ₃ = ΔFx ₃ (92c)
∂Fx ₄ = ΔFx ₄ (92d)
However, at this time, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 are the driving force target values Fx ₁ **, Fx ₂ **, and Fx ₃ * of the wheels 1 to 4, respectively. *, Fx ₄ ** is obtained by referring to the driving force correction amount map. In addition, when the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of each wheel 1 to 4 are obtained based on the flowchart of FIG. By referring to the vehicle behavior sensitivity map from Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ **, the vehicle longitudinal force, vehicle lateral force, yaw moment with respect to the driving force change of each wheel 1-4 The respective sensitivities K _ix , K _iy and K _iM are obtained. When the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each wheel 1 to 4 are obtained based on the flowchart of FIG. The tire lateral force sensitivities k ₁ , k ₂ , k ₃ , and k ₄ with respect to the driving force change of each wheel at Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** are obtained.

Thus, in the third embodiment (the invention described in claim 8), in a vehicle capable of independently driving four wheels, the target value Fx ** of the vehicle longitudinal force of the vehicle, and the target value M * of the yaw moment. * Is determined as a target value for vehicle behavior (see step 61 in FIG. 20), and driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to ₄ are set. (Refer to step 71 in FIG. 20), the vehicle longitudinal force realized by the set driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 The basic value Fx ## and the basic value M ## of the yaw moment are calculated as the basic values of the vehicle behavior (see step 81 in FIG. 20), and the target values Fx ** and M ** of the vehicle behavior are calculated. The error ΔFx, ΔM between the vehicle behavior basic values Fx ##, M ## is calculated as the vehicle behavior error (see step 91 in FIG. 20). Calculated by the vehicle behavior of the error DerutaFx, driving force correction amount DerutaFx ₁ of each wheel to reduce ΔM, ΔFx _2, ΔFx _3, calculates the ΔFx ₄ (see step 100 in FIG. 21), the driving of the respective wheels 1-4 The sum of the force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## and the calculated driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ 4 driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** are determined (see step 110 in FIG. 21), and the determined driving force targets of the respective wheels 1 to 4 are determined. The driving forces of the wheels 1 to 4 are controlled so that the values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** are obtained (see step 120 in FIG. 21). That is, according to the third embodiment (the invention described in claim 8), the target value Fy ** is not set for the vehicle lateral force Fy, and only the vehicle longitudinal force Fx and the yaw moment M are set to the target value Fx *. *, M ** are determined, and the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx of the wheels 1 to 4 that realize these two target values Fx **, M ** _{4 Since} ** is determined, it is not necessary to design the target value of the vehicle lateral force Fy and to hold the target value of the vehicle lateral force Fy in the controller 8. Vehicle prices can be reduced by reducing computer memory consumption.

In the above equation (81), the yaw rate γ and the centripetal acceleration Yg are not completely dependent and have a degree of freedom of dβ / dt, and therefore the degree of freedom is similarly between the vehicle lateral force Fy and the yaw moment M. is there. Therefore, according to the third embodiment (the invention described in claim 10), the driving force recorrection amount of each wheel 1 to 4 that brings the vehicle lateral force Fy close to the target value Fy **, that is, the vehicle lateral direction. The driving force recorrection amounts ∂Fx ₁ , ∂Fx ₂ , ∂Fx ₃ , and ∂Fx ₄ for each wheel 1 to 4 that change the force Fy from zero within a range of error of the predetermined amount ∂Fy are calculated (see FIG. 21). Step 111), and the driving force re-correction amounts ∂Fx ₁ and ∂Fx calculated for the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the wheels _{1 to 4} , respectively. ₂ , ∂Fx ₃ , and ∂Fx ₄ are added again and reset as driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** of each wheel 1 to 4 (FIG. 21), the vehicle lateral force Fy is brought close to the vehicle lateral force target value Fy ** suitable for the driver within the range of this degree of freedom. Theft becomes possible, and can be expected to improve drivability.

In the third embodiment (the invention described in claim 11), the driving force maximum values Fxmax ₁ , Fxmax ₂ , Fxmax ₃ , and Fxmax ₄ of each of the wheels 1 to ₄ are set (see step 3020 in FIG. 22). Based on the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** of _{1 to 4} and the set driving force maximum values Fxmax ₁ , Fxmax ₂ , Fxmax ₃ , Fxmax ₄ Then, an amount ∂Fyreal (= Ψ × ∂Fy) that can change the vehicle lateral force Fy within a range of error from zero to a predetermined amount ∂Fy is calculated (see steps 3030 to 3050 in FIG. 22). Driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to ₄ that change the vehicle lateral force Fy by this amount ∂Freal are changed to driving force recorrection amounts ∂Fx ₁ , ∂ fx _2, ∂Fx _3, are set as ∂Fx ₄ (See step 112 in FIG. 21). That is, according to the third embodiment (the invention described in claim 11), the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the respective wheels 1 to ₄ are respectively set. driving force maximum value Fxmax ₁ ring _{1~4, Fxmax 2, Fxmax 3,} Fxmax whether is varied how much driving force after against ₄ the driving force margin _{Fmx 1, Fmx 2, Fmx 3} , the Fmx ₄ Since the driving force margin Fmx ₁ , Fmx ₂ , Fmx ₃ , Fmx ₄ is used to determine how much the vehicle lateral force Fy can be asymptotic to the target value Fy **, each wheel 1 It is possible to bring the vehicle lateral force Fy close to the target value Fy ** that is suitable for the driver without exceeding the driving force limit of ˜4, and improvement in drivability can be expected.

  Next, the description of the fourth embodiment shown in FIGS. 24 and 25 will be made. Again, the difference from the first embodiment will be mainly described. In step 42 of FIG. 24, the vehicle target value Fy * of the vehicle lateral force is set to the vehicle front-rear direction which is the sum of the target driving force and the target braking force. The directional force static target value Fx *, the rotation angle θ of the steering wheel 5, and the vehicle speed V are set based on the vehicle lateral force static target value map shown in FIG. Here, the yaw rate static target value map is not provided in the controller 8, and the static target value * of the yaw rate is not set in step 42 in FIG. The purpose of not setting the yaw rate static target value map is to reduce the memory usage of the controller 8 and the calculation load.

  In step 62 of FIG. 24, the driver can set the dynamic target value Fx ** of the vehicle longitudinal force and the dynamic target value Fy ** of the vehicle lateral force within a range that can be realized by the driving force distribution of the wheels 1 to 4. In order to optimize the controllability, a time delay element is added to each of the static target values Fx * and Fy *. For the static target value Fx * of the vehicle longitudinal force, perform a smoothing process using a second-order lag transfer function, and for the static target value Fy * of the vehicle lateral force, use a corresponding transfer function. Thus, the dynamic target value Fx ** of the vehicle longitudinal force and the dynamic target value Fy ** of the vehicle lateral force are obtained. In particular, the response of the dynamic target value Fy ** of the vehicle lateral force includes a time delay element that can be realized for each traveling condition. In the third embodiment, the dynamic target value M of the yaw moment is obtained using a transfer function obtained by multiplying the transfer function of the time delay element used when obtaining the dynamic target value γ ** of the yaw rate by a differential element. ** is required, but not required in the fourth embodiment.

In step 72 of FIG. 24, each wheel 1 to 1 is determined based on the static target values Fx ₁ *, Fx ₂ *, Fx ₃ *, and Fx ₄ * of the driving forces of the wheels 1 to 4 set in step 50. The driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, and Fx ₄ ## of ₄ are obtained by the following equations (32) to (35) as in the first embodiment.

Fx ₁ ## = Fx _all ## × (η / 2) −ΔFx _all ## × Δη / 2 (32)
Fx ₂ ## = Fx _all ## × (η / 2) −ΔFx _all ## × Δη / 2 (33)
Fx ₃ ## = Fx _all ## × (1−η) / 2−ΔFx _all ## × (1−Δη) / 2
... (34)
Fx ₄ ## = Fx _all ## × (1−η) / 2−ΔFx _all ## × (1−Δη) / 2
... (35)
The front wheel driving force distribution η and the front wheel distribution Δη of the left and right wheel driving force difference in the equations (32) to (35) are η = Δη = 0.6. Further, ΔFx _all ## in the equations (32) to (35) is entered in the static target value Fx * of the vehicle longitudinal force when the dynamic target value Fx ** of the vehicle longitudinal force is obtained in step 60. The time delay element is expressed as Fx ₁ ** + Fx ₂ * which is the sum of the static target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the driving forces of the wheels 1 to 4. * + Fx ₃ ** + Fx ₄ **.

Here, ΔFx _all ## in the equations (32) to (35) is obtained as follows. That is, a linear two-wheel model in which a vehicle is linearly approximated (Masato Abe, 2nd edition, “Automotive motion and control”, Sankaido Co., Ltd., April 10, 2003, Chapter 3 Section 3.2.1 ) to consider the case where joined by left and right wheel driving force difference ΔFx _all ##, the linear two-wheel model of the yaw rate model following control system the response is designed to be dynamic target value gamma ** the yaw rate (Kanai Kimio, Norimasa Ochi, Taketoshi Kawamata, “Vehicle Control”, Tsubaki Shoten, January 20, 2004, Chapter 3, Section 3.2), and the static force of each wheel 1-4 in steady state The target value Fx ₁ *, Fx ₂ *, Fx _{3 *} , and Fx ₄ * is obtained from the following equation (36) corrected so as not to cause a deviation.

ΔFx _all ## = {s ² + (− a ₁₁ −a ₂₂ ) s + (a ₁₁ a ₂₂ −A ₁₂ a ₂₁ )}
/ {B ₂₂ · s + (a ₂₁ b ₁₁ −a ₁₁ b ₂₁ )} × f _r (s)
× {(a ₂₁ b ₁₁ −a ₁₁ b ₂₁ ) θ / 16 + (− a ₁₁ b ₂₂ ) ΔFx _all #}
_{/ {A 11 b 22 -a 12} a 21}
- _{[{b 21 · s + (a} 21 b 11 -a 11 b 21)}
_{/ {B 22 · s + (} - a 11 b 22)} ] × theta / 16
... (36)
In the third embodiment, f _r (s) in Expression (36) is a time delay element that is included in the static target value γ * of the yaw rate when the dynamic target value γ ** of the yaw rate is obtained in step 61. However, in the fourth embodiment, since the dynamic target value γ ** of the yaw rate is not obtained, the dynamic target value Fy ** of the vehicle lateral force is determined from the vehicle mass m and the vehicle speed V. The dynamic target value γ ** of the yaw rate is obtained by the following equation (93) that is a value divided by the above, and ΔFx _all ## is obtained based on the dynamic target value γ ** of the yaw rate.

γ ** = Fy ** / mV (93)
Kf, Kr [N / rad] in the equation (36) is a cornering force per unit side slip angle when the side slip angle of the front wheel and the rear wheel is sufficiently small.

Also, the coefficients a ₁₁ , a ₁₂ , a ₂₁ , a ₂₂ , b ₁₁ , b ₂₁ , b ₂₂ , and ΔFx _all # in the equation (36) are the following values, respectively.

a ₁₁ = − (2 / mV) (K _f + K _r ) (Supplement 4)
a ₁₂ = − (2 / mV ² ) (K _f L _f −K _r L _r ) −1 (Supplement 5)
a ₂₁ = − (2 / I) (K _f L _f −K _r L _r ) (Supplement 6)
a ₂₂ = − (2 / IV) (K _f L _f ² + K _r L _r ² ) (Supplement 7)
b ₁₁ = 2K _f / mV (Supplement 8)
b ₂₁ = 2K _f L _f / I (Supplement 9)
b ₂₂ = L _t / 2I (Supplement 10)
ΔFx _all # = (Fx ₂ * + Fx ₄ *) − (Fx ₁ * + Fx ₃ *) (Supplement 11)
In the equations (A4) to (A11), m is a vehicle mass [kg], V is a vehicle speed [m / s], and I is a vehicle yaw inertia moment [kg · m ² ].

As described above, the method of obtaining ΔFx _all ## in the fourth embodiment is slightly different from that in the third embodiment.

In step 82 of FIG. 24, the basic values of the vehicle behavior realized by the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## obtained in step 72 are obtained. That is, the basic value Fx ## of the vehicle longitudinal force and the basic value Fy ## of the vehicle lateral force are obtained by the following equations (37) and (38), respectively.

Fx ## = Fx ₁ ## + Fx ₂ ## + Fx ₃ ## + Fx ₄ ## (37)
Fy ## = Fy ₁ ## + Fy ₂ ## + Fy ₃ ## + Fy ₄ ## (38)
Unlike the first embodiment, the fourth embodiment does not calculate the basic value M ## of the yaw moment. Thereby, the calculation load of the controller 8 can be reduced.

In step 92 of FIG. 24, the target value of the vehicle behavior set in step 62 and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to 4 are set. The difference between the vehicle behavior basic value and the vehicle longitudinal force dynamic target value Fx ** and the vehicle longitudinal force basic value Fx ##, the vehicle lateral force dynamic target An error ΔFy between the value Fy ** and the basic value Fy ## of the vehicle lateral force is obtained by the following equations (42) and (43).

ΔFx = Fx ** − Fx ## (42)
ΔFy = Fy ** − Fy ## (43)
In the fourth embodiment, since the dynamic target value M ** of the yaw moment and the basic value Fy ## of the yaw moment are not obtained, the dynamic target value M ** of the yaw moment is different from the first embodiment. As an error ΔM with respect to the basic value M ## of the yaw moment, zero is set as in the following equation (94).

ΔM = 0 (94)
In step 113 of FIG. 25, driving force recorrection amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, ∂Fx ₄ ′ of the respective wheels 1 to 4 are obtained. The driving force re-correction amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, ∂Fx ₄ ′ are used as the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, The value added to Fx ₄ ** is changed to the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each wheel 1-4, that is, the following formula (95a) to formula In (95d), the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the wheels 1 to ₄ are reset.

Fx ₁ ** ← Fx ₁ ** + ∂Fx ₁ '(95a)
Fx ₂ ** ← Fx ₂ ** + ∂Fx ₂ '(95b)
Fx ₃ ** ← Fx ₃ ** + ∂Fx ₃ '(95c)
Fx ₄ ** ← Fx ₄ ** + ∂Fx ₄ '(95d)
Here, the flow of FIG. 26 (subroutine of step 113 in FIG. 25) shows how to obtain the driving force recorrection amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, and ∂Fx ₄ ′ of the wheels 1 to 4. ).

In FIG. 26, in Step 4010, the error ΔFx between the dynamic target value Fx ** of the vehicle longitudinal force and the basic value Fx ## of the vehicle longitudinal force is zero, and the dynamic target value Fy ** of the vehicle lateral force is The error ΔFy with respect to the basic value Fy ## of the vehicle lateral force is zero, the error ΔM regarding the yaw moment is a predetermined amount ∂M, and each wheel 1 that realizes ΔFx = 0, ΔFy = 0, ΔM = ∂M 4 driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are obtained using the same processing as in step 100 of FIG. 25, and the obtained driving force correction values ΔFx ₁ , ΔFx ₂ , ΔFx ₃ and ΔFx ₄ are converted into driving force recorrection amounts ∂∂Fx ₁ ′, ∂∂Fx ₂ ′, ∂∂Fx ₃ ′, ∂∂ for each wheel 1 to ₄ as in the following formulas (96a) to (96d): Set as Fx ₄ '.

∂∂Fx ₁ '= ΔFx ₁ (96a)
∂∂Fx ₂ '= ΔFx ₂ (96b)
∂∂Fx ₃ '= ΔFx ₃ (96c)
∂∂Fx ₄ '= ΔFx ₄ (96d)
However, at this time, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ of the wheels 1 to 4 are the driving force target values Fx ₁ **, Fx ₂ **, and Fx ₃ * of the wheels 1 to 4, respectively. *, Fx ₄ ** is obtained by referring to the driving force correction amount map. In addition, when the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of each wheel 1 to 4 are obtained based on the flowchart of FIG. By referring to the vehicle behavior sensitivity map from Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ **, the vehicle longitudinal force, vehicle lateral force, yaw moment with respect to the driving force change of each wheel 1-4 The respective sensitivities K _ix , K _iy and K _iM are obtained. When the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each wheel 1 to 4 are obtained based on the flowchart of FIG. The tire lateral force sensitivities k ₁ , k ₂ , k ₃ , and k ₄ with respect to the driving force change of each wheel at Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** are obtained.

In step 4020, the driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ [N] of each wheel 1 to 4 and the driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , Fmin _{4 of} each wheel 1 to 4 are determined. [N] is set. As the setting method of the driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ of each wheel 1-4 and the driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , Fmin ₄ of each wheel 1-4, One of the three methods shown in <18> to <20> above for the three embodiments is used.

In step 4030, the driving force allowance Fmx of each wheel 1 to 4 when the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of each wheel 1 to ₄ are output. ₁ , Fmx ₂ , Fmx ₃ , Fmx ₄ are set. Next, two methods are shown as a method of setting the driving force margin for each of the wheels 1 to 4.
<23> Setting method 1 of driving force margin for each wheel
The driving force margins Fmx ₁ , Fmx ₂ , Fmx ₃ , and Fmx ₄ of the wheels 1 to 4 are set to a sufficiently small value as compared with the maximum driving force that can be output from the wheels 1 to 4. As this sufficiently small value, for example, 200 [N] is set.
<24> Setting method 2 of driving force margin for each wheel
This is a setting method (invention according to claim 13) for setting the driving force margin for each wheel 1 to 4 with a variable value according to the driving force maximum value or the driving force minimum value, and is set in step 4020. The driving force maximum values Fmax ₁ , Fmax ₂ , Fmax ₃ , Fmax ₄ of each wheel 1 to ₄ and the driving force minimum values Fmin ₁ , Fmin ₂ , Fmin ₃ , Fmin ₄ of each wheel 1 to ₄ , and each wheel From the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of 1 to 4, the driving force margin Fmx ₁ , Fmx ₂ , Fmx ₃ , Fmx of each wheel 1 to 4 is obtained. _{4 is obtained according} to the following equations (97a) to (97d) and equations (98a) to (98d).

[1] _{∂∂Fx 1 '≧ 0, ∂∂Fx 2} ' ≧ 0, ∂∂Fx 3 '≧ 0, ∂∂Fx 4' For _{≧ 0 Fmx 1 = Fmax 1 -Fx} 1 ** ... (97a)
Fmx ₂ = Fmax ₂ -Fx ₂ ** (97b)
Fmx ₃ = Fmax ₃ -Fx ₃ ** (97c)
Fmx ₄ = Fmax ₄ -Fx ₄ ** (97d)
[2] When ∂∂Fx ₁ ′ <0, ∂∂Fx ₂ ′ <0, ∂∂Fx ₃ ′ <0, ∂∂Fx ₄ ′ <0 Fmx ₁ = Fx ₁ ** − Fmin ₁ (98a)
Fmx ₂ = Fx ₂ ** − Fmin ₂ (98b)
Fmx ₃ = Fx ₃ ** − Fmin ₃ (98c)
Fmx ₄ = Fx ₄ ** − Fmin ₄ (98d)
In step 4040, by using the driving force margin _{Fmx 1, Fmx 2, Fmx 3} , Fmx 4 of the wheels 1 to 4 are set in this manner, the error ΔM predetermined amount ∂M for yaw moment The amount ψ ′ [anonymous number] of how much can be corrected is obtained according to the following equation (99).

Ψ ′ = min (Fmx ₁ / ∂∂Fx ₁ ′, Fmx ₂ / ∂∂Fx ₂ ′, Fmx ₃ / ∂∂Fx ₃ ′, Fmx ₄ / ∂∂Fx ₄ ′)
... (99)
Equation (99) is a value obtained by dividing the driving force margin for each wheel 1 to 4 by the driving force recorrection amount (that is, Fmx ₁ / ∂∂Fx ₁ ′, Fmx ₂ / ∂∂Fx ₂ ′, Fmx ₃ / ∂∂). The minimum value among the four values Fx ₃ ′, Fmx ₄ / ∂∂Fx ₄ ′) is adopted.

In step 4050, a value obtained by multiplying the predetermined amount ∂M by this ratio ψ 'is replaced as an error ΔM for the yaw moment, and each wheel 1 that realizes ΔFx = 0, ΔFy = 0, ΔM = ψ' × ∂M again. ˜4 driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ are obtained using the same process as in step 100 of FIG. 25, and the obtained driving force correction amounts ΔFx ₁ , ΔFx _{2 of} the respective wheels 1 to 4 are obtained. , ΔFx ₃ , ΔFx ₄ are converted into driving force recorrection amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, ∂Fx ₄ for each wheel 1 to ₄ as in the following formulas (100a) to (100d): Set as'.

∂Fx ₁ '= ΔFx ₁ (100a)
∂Fx ₂ '= ΔFx ₂ (100b)
∂Fx ₃ '= ΔFx ₃ (100c)
∂Fx ₄ '= ΔFx ₄ (100d)
However, at this time, the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of the wheels 1 to 4 are the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ ** of the wheels 1 to 4, respectively. , Fx ₄ ** by referring to the driving force correction amount map. In addition, when the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ of each wheel 1 to 4 are obtained based on the flowchart of FIG. Refers to the vehicle behavior sensitivity map from Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ **, and the sensitivity of the vehicle longitudinal force, vehicle lateral force, and yaw moment for each wheel driving force change _Find K _ix , K _iy , and K _iM . When the driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , and ΔFx ₄ for each wheel 1 to 4 are obtained based on the flowchart of FIG. The tire lateral force sensitivities k ₁ , k ₂ , k ₃ , and k ₄ with respect to the driving force change of each wheel at Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** are obtained.

As described above, in the fourth embodiment (the invention according to claim 9), in a vehicle capable of independently driving four wheels, the target value Fx ** of the vehicle longitudinal force and the target value of the vehicle lateral force are determined. Fy ** is determined as a target value of the vehicle behavior (see step 62 in FIG. 24), and the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1-4. (See step 72 in FIG. 24), and the vehicle front and rear realized by the set driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 The basic value Fx ## of the directional force and the basic value Fy ## of the vehicle lateral force are calculated as the basic values of the vehicle behavior (see step 82 in FIG. 24), and the target values Fx ** and Fy ** of the vehicle behavior are calculated. And errors ΔFx and ΔFy between the calculated vehicle behavior basic values Fx ## and Fy ## are calculated as vehicle behavior errors (see step 92 in FIG. 24). The computed vehicle behavior of the error DerutaFx, driving force correction amount DerutaFx ₁ for the wheels 1 to 4 to reduce the ΔM, ΔFx _2, ΔFx _3, calculates the ΔFx ₄ (see step 100 in FIG. 25), each wheel 1 Is the sum of the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## to _{4 and} the calculated driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ The driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the wheels 1 to ₄ are determined (see step 110 in FIG. 25), and the determined wheels 1 to ₄ are determined. The driving force of each of the wheels 1 to 4 is controlled so as to obtain the driving force target value (see step 61 in FIG. 24). That is, according to the fourth embodiment (the invention described in claim 9), the target value M ** is not set for the yaw moment M, and only the target value Fx * for the vehicle longitudinal force Fx and the vehicle lateral force Fy. *, Fy ** are determined, and the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx of the wheels 1 to 4 that realize these two target values Fx **, Fy ** _{4 Because} ** is determined, it is no longer necessary to design the target value of yaw moment M and hold the target value of yaw moment M in controller 8, reducing the design man-hours and memory consumption of in-vehicle computer The vehicle price can be reduced by reducing the amount.

As described in the effect of the third embodiment, since there is a degree of freedom between the vehicle lateral force Fy and the yaw moment M, according to the fourth embodiment (the invention according to claim 12), the yaw moment For M, the driving force recorrection amount of each wheel 1 to 4 that approaches the target value M **, that is, the driving force of each wheel 1 to 4 that changes the yaw moment M within a range of error from zero to a predetermined amount ∂M. Re-correction amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, and ∂Fx ₄ ′ are calculated (see step 113 in FIG. 25), and the driving force target values Fx ₁ **, Fx of the wheels 1 to ₄ are calculated. _The value obtained by adding the calculated driving force re-correction amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′ and ∂Fx ₄ ′ to ₂ **, Fx ₃ **, Fx ₄ ** again for each wheel 1-4 the driving force target value _{Fx 1 **, Fx 2 **,} Fx 3 **, reconfigure as Fx ₄ ** because (see step 114 in FIG. 25), Yomo Can be brought close to cement M to the target value M ** of the yaw moment is suitable for the driver in the range of the degrees of freedom and will be expected to improve drivability.

In the fourth embodiment (the invention described in claim 13), the driving force maximum values Fxmax ₁ , Fxmax ₂ , Fxmax ₃ , and Fxmax ₄ of the wheels 1 to ₄ are set (see step 4020 in FIG. 26). Based on the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, Fx ₄ ** of _{1 to 4} and the set driving force maximum values Fxmax ₁ , Fxmax ₂ , Fxmax ₃ , Fxmax ₄ Then, an amount ∂Mreal (= Ψ ′ × ∂M) that can change the yaw moment M within a range of error from zero to a predetermined amount ∂M is calculated (see steps 4030 to 4050 in FIG. 26), and the yaw moment M is calculated. The driving force correction amounts ΔFx ₁ , ΔFx ₂ , ΔFx ₃ , ΔFx ₄ for changing the moment M by this amount ∂Mreal are changed to the driving force recorrection amounts ∂Fx ₁ ′, ∂Fx ₂ for each wheel 1-4. It is set as', ∂Fx ₃ ', ∂Fx ₄ ' (Figure 25, step 114). That is, according to the fourth embodiment (the invention described in claim 13), the driving force target values Fx ₁ **, Fx ₂ **, Fx ₃ **, and Fx ₄ ** of the respective wheels 1 to ₄ are respectively set. driving force maximum value Fxmax ₁ ring _{1~4, Fxmax 2, Fxmax 3,} Fxmax whether is varied how much driving force after against ₄ the driving force margin _{Fmx 1, Fmx 2, Fmx 3} , the Fmx ₄ Since the driving force margin Fmx ₁ , Fmx ₂ , Fmx ₃ , Fmx ₄ is used to determine how much the yaw moment M can be asymptotic to the target value M **, each wheel 1 to 4 is obtained. It is possible to bring the yaw moment M close to the target value M ** that is suitable for the driver without exceeding the limit of the driving force, and improvement in drivability can be expected.

  FIG. 27 is a flowchart of the fifth embodiment, which replaces steps 81 to 110 in FIGS. 20 and 21 of the third embodiment. The same step number is attached | subjected to the part same as FIG. 16 of 2nd Embodiment.

27, operations in steps 201 and 211 are the same as steps 81 and 91 in FIG. That is, in step 201, the basic value of the vehicle behavior realized by the basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 (the basic value of the vehicle longitudinal force). Fx ##, the basic value M ## of the yaw moment) is estimated, and in step 211, the target value of the vehicle behavior (the dynamic target value Fx ** of the vehicle longitudinal force, the dynamic target value γ ** of the yaw rate) and , Errors ΔFx and ΔM from the basic values of the vehicle behavior obtained in step 201 (basic value Fx ## of the vehicle longitudinal force and basic value M ## of the yaw moment) are expressed by the following equations (101) and (102 ) Respectively.

ΔFx = Fx ** − Fx ## (101)
ΔM = M ** − M ## (102)
Since the dynamic target value Fy ** of the vehicle lateral force and the basic value Fy ## of the vehicle lateral force are not obtained, the dynamic target value Fy ** of the vehicle lateral force and the basic value Fy of the vehicle lateral force are determined. As an error ΔFy from ##, zero is set as in the following equation (103).

ΔFy = 0 (103)
In step 251, the driving force recorrection amounts ∂Fx ₁ , ｘFx ₂ , ∂Fx ₃ , and ∂Fx ₄ of each wheel 1 to ₄ are obtained according to the flowchart of FIG. Re-correction amounts ∂Fx ₁ , ∂Fx ₂ , ∂Fx ₃ , ∂Fx ₄ are added to the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1-4 The obtained values are again set as the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to 4, that is, according to the following equations (104a) to (104d). The driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to ₄ are reset.

Fx ₁ ## ← Fx ₁ ## + ∂Fx ₁ (104a)
Fx ₂ ## ← Fx ₂ ## + ∂Fx ₂ (104b)
Fx ₃ ## ← Fx ₃ ## + ∂Fx ₃ (104c)
Fx ₄ ## ← Fx ₄ ## + ∂Fx ₄ (104d)
FIG. 28 is a flowchart of the sixth embodiment, which replaces steps 82 to 110 in FIGS. 24 and 25 of the fourth embodiment. The same step number is attached | subjected to the part same as FIG. 16 of 2nd Embodiment.

In FIG. 28, operations in steps 202 and 212 are the same as steps 82 and 92 in FIG. That is, in step 202, the basic value of the vehicle behavior realized by the basic driving force values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of each wheel 1 to 4 (the basic value of the vehicle longitudinal force). Fx ##, the vehicle lateral force basic value Fy ##) is estimated. In step 212, the vehicle behavior target value (vehicle longitudinal force dynamic target value Fx **, vehicle lateral force dynamic target value). Fy **) and errors ΔFx and ΔFy between the basic values of the vehicle behavior obtained in step 202 (the basic value Fx ## of the vehicle longitudinal force and the basic value Fy ## of the vehicle lateral force) are expressed by the following equations: (105) and Equation (106). The yaw moment error ΔM is set to zero as shown in the following equation (83).

ΔFx = Fx ** − Fx ## (105)
ΔFy = Fy ** − Fy ## (106)
Since the dynamic target value M ** of the yaw moment and the basic value Fy ## of the yaw moment are not obtained, the error ΔM between the dynamic target value M ** of the yaw moment and the basic value M ## of the yaw moment is as follows: As shown in equation (107), zero is set.

ΔM = 0 (107)
In step 253, the driving force recorrection amounts ∂Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, ∂Fx ₄ ′ of the respective wheels 1 to ₄ are obtained in accordance with the flowchart of FIG.力 Fx ₁ ′, ∂Fx ₂ ′, ∂Fx ₃ ′, and ∂Fx ₄ ′ are the basic values of the driving force Fx ₁ ##, Fx ₂ ##, Fx ₃ ## , Fx ₄ ##, the driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to 4 are renewed, that is, the following equation (108a) The driving force basic values Fx ₁ ##, Fx ₂ ##, Fx ₃ ##, Fx ₄ ## of the wheels 1 to ₄ are reset by the formula (108d).

Fx ₁ ## ← Fx ₁ ## + ∂Fx ₁ '(108a)
Fx ₂ ## ← Fx ₂ ## + ∂Fx ₂ '(108b)
Fx ₃ ## ← Fx ₃ ## + ∂Fx ₃ '(108c)
Fx ₄ ## ← Fx ₄ ## + ∂Fx ₄ '(108d)
The present invention is not limited to the vehicle shown in FIG. 1 but a vehicle in which the rear wheels can be steered at an angle different from the front wheels, and the steering angles δ ₁ , δ of the wheels 1 to 4 independently of the steering amount θ of the steering 5. _{The present} invention is also applicable to vehicles equipped with steer-by-wire, such as vehicles that can control ₂ , δ ₃ and δ ₄ .

  The function of the vehicle behavior target value determining means according to claim 1 is the function of step 60 in FIG. 6, the function of the driving force basic value setting means is the step 70 of FIG. 6, and the function of the vehicle behavior basic value calculating means is the function of FIG. In step 80, the function of the vehicle behavior error calculating means is in step 90 of FIG. 6, the function of the driving force correction amount calculating means is in step 100 of FIG. 7, and the function of the driving force target value determining means is in step 110 of FIG. The function of each wheel driving force control means is performed by step 120 in FIG.

  The function of the vehicle behavior target value determining means according to claim 8 is the function of step 61 in FIG. 20, the function of the driving force basic value setting means is the step 71 of FIG. 20, and the function of the vehicle behavior basic value calculating means is the function of FIG. In step 81, the function of the vehicle behavior error calculating means is in step 91 in FIG. 20, the function of the driving force correction amount calculating means is in step 100 in FIG. 21, and the function of the driving force target value determining means is in step 110 in FIG. The function of each driving force control means is fulfilled by step 120 in FIG.

  The function of the vehicle behavior target value determining means according to claim 9 is the function of step 62 in FIG. 24, the function of the driving force basic value setting means is the step of FIG. 24, and the function of the vehicle behavior basic value calculating means is the function of FIG. 24, the function of the vehicle behavior error calculating means is according to step 92 in FIG. 24, the function of the driving force correction amount calculating means is according to step 100 in FIG. 25, and the function of the driving force target value determining means is according to step 110 in FIG. The function of each driving force control means is fulfilled by step 120 in FIG.

The schematic block diagram of the four-wheel independent drive vehicle of 1st Embodiment of this invention. The figure showing the braking / driving force, tire lateral force, steering angle, etc. of each wheel in a four-wheel independent drive vehicle. The figure showing the braking / driving force, tire lateral force, and tire force which is the resultant force in a certain wheel. The tire characteristic view showing the relationship between driving force and tire lateral force. Considering the non-linear relationship between the driving force and the tire lateral force for each wheel, the target value for the vehicle longitudinal force, the target value for the vehicle lateral force, and the target value for the yaw moment are achieved. The wave form diagram for demonstrating the method of calculating | requiring by feedforward. The flowchart for demonstrating the torque distribution control of 1st Embodiment. The flowchart for demonstrating the torque distribution control of 1st Embodiment. The characteristic diagram of a target driving force. The characteristic figure of target braking force. The characteristic figure of the static target value of vehicle lateral force. The characteristic figure of the static target value of a yaw rate. The characteristic figure of the driving force static target value of each wheel. The tire characteristic figure showing the relationship between the driving force and tire lateral force which change corresponding to a side slip angle. The tire characteristic view showing the relationship between the driving force and tire lateral force which change corresponding to a side slip angle and a road surface friction coefficient (or wheel load). The characteristic diagram of the driving force correction amount of each wheel. The flowchart for demonstrating how to obtain | require the driving force target value of each wheel of 2nd Embodiment. The flowchart for demonstrating how to obtain | require the driving force correction amount of each wheel. The flowchart for demonstrating how to obtain | require the driving force correction amount of each wheel. FIG. 6 is a characteristic diagram of vehicle longitudinal force sensitivity, vehicle lateral force sensitivity, and yaw moment sensitivity with respect to changes in driving force for the left front wheel. The flowchart for demonstrating the torque distribution control of 3rd Embodiment. The flowchart for demonstrating the torque distribution control of 3rd Embodiment. The flowchart for demonstrating how to obtain | require the driving force recorrection amount of each wheel of 3rd Embodiment. The characteristic view showing the relationship between motor temperature and the maximum output which can suppress motor overheating. The flowchart for demonstrating the torque distribution control of 4th Embodiment. The flowchart for demonstrating the torque distribution control of 4th Embodiment. The flowchart for demonstrating how to obtain | require the driving force recorrection amount of each wheel of 4th Embodiment. The flowchart for demonstrating how to obtain | require the driving force target value of each wheel of 6th Embodiment. The flowchart for demonstrating how to obtain | require the driving force target value of each wheel of 7th Embodiment.

Explanation of symbols

1 to 4 wheels 8 controller 11 to 14 motor (actuator)

Claims (13)

In vehicles that can drive all four wheels independently,
Vehicle behavior target value determining means for determining a vehicle longitudinal force target value, a vehicle lateral force target value, and a yaw moment target value as a vehicle behavior target value;
Driving force basic value setting means for setting the driving force basic value of each wheel;
Vehicle behavior basic value calculation means for calculating the basic value of the vehicle longitudinal force, the basic value of the lateral force of the vehicle, and the basic value of the yaw moment as the basic values of the vehicle behavior realized by the set basic driving force value of each wheel. When,
Vehicle behavior error calculating means for calculating an error between the target value of the vehicle behavior and the calculated basic value of the vehicle behavior as an error of the vehicle behavior;
Driving force correction amount calculating means for calculating the driving force correction amount of each wheel for reducing the error of the calculated vehicle behavior;
Driving force target value determining means for determining a driving force target value of each wheel by the sum of the driving force basic value and the calculated driving force correction amount;
A driving force distribution device for a four-wheel independent driving vehicle, comprising: wheel driving force control means for controlling the driving force of each wheel so as to obtain the determined driving force target value of each wheel. The driving force target value determining means includes
A driving force temporary value calculating means for calculating the sum of the driving force correction amount and the driving force basic value as a driving force temporary value of each wheel;
Vehicle behavior basic value recalculation means for calculating again the basic value of the vehicle longitudinal force, the basic value of the lateral force of the vehicle, and the basic value of the yaw moment as the basic value of the vehicle behavior realized by the calculated driving force temporary value; ,
Vehicle behavior error recalculation means for calculating again an error between the vehicle behavior target value and the recalculated vehicle behavior basic value as a vehicle behavior error;
Driving force correction amount recalculating means for calculating again the driving force correction amount of each wheel that reduces the error of the vehicle behavior calculated again;
Vehicle behavior error compensation processing means for performing processing for compensating for an error in vehicle behavior by replacing the sum of the driving force temporary value and the recalculated driving force correction amount with the driving force target value. The driving force distribution device for a four-wheel independent drive vehicle according to claim 1.   Vehicle behavior change sensitivity calculating means for calculating the sensitivity of the vehicle longitudinal direction force, the vehicle lateral force sensitivity, and the yaw moment sensitivity with respect to the driving force change for each wheel as the vehicle behavior change sensitivity is provided. The driving force distribution device for a four-wheel independent drive vehicle according to claim 1 or 2, wherein the means calculates the driving force correction amount based on the calculated sensitivity of the vehicle behavior change.   Tire lateral force sensitivity estimation means for estimating the sensitivity of the tire lateral force with respect to the driving force change for each wheel is provided, and the driving force correction amount calculating means is configured to determine the driving force based on the estimated tire lateral force sensitivity. The driving force distribution device for a four-wheel independent drive vehicle according to claim 1 or 2, wherein a correction amount is calculated.   Steering angle detection means for detecting the steering angle of each wheel, wherein the vehicle behavior basic value calculation means calculates the basic value of the vehicle behavior based on the detected steering angle of each wheel, and the driving force The driving force distribution device for a four-wheel independent driving vehicle according to claim 1 or 2, wherein the correction amount calculating means calculates the driving force correction amount based on the detected steering angle of each wheel.   Wheel load estimation / detection means for estimating or detecting the wheel load of each wheel is provided, and the vehicle behavior basic value calculation means calculates the basic value of the vehicle behavior based on the estimated or detected wheel load of each wheel. The four-wheel independent vehicle according to claim 1, wherein the driving force correction amount calculating means calculates the driving force correction amount based on the estimated or detected wheel load of each wheel. Driving force distribution device for driving vehicles.   Road surface friction coefficient estimating means for estimating the road surface friction coefficient of each wheel, and the vehicle behavior basic value calculating means calculates the basic value of the vehicle behavior based on the estimated road surface friction coefficient of each wheel; The drive of a four-wheel independent drive vehicle according to claim 1 or 2, wherein the driving force correction amount calculating means calculates the driving force correction amount based on the estimated road surface friction coefficient of each wheel. Power distribution device. In vehicles that can drive all four wheels independently,
Vehicle behavior target value determining means for determining a target value of the vehicle longitudinal force of the vehicle and a target value of the yaw moment as a target value of the vehicle behavior;
Driving force basic value setting means for setting the driving force basic value of each wheel;
Vehicle behavior basic value calculation means for calculating the basic value of the vehicle longitudinal force and the basic value of the yaw moment, which are realized by the set driving force basic value of each wheel, as the basic value of the vehicle behavior;
Vehicle behavior error calculating means for calculating an error between the target value of the vehicle behavior and the calculated basic value of the vehicle behavior as an error of the vehicle behavior;
Driving force correction amount calculating means for calculating the driving force correction amount of each wheel for reducing the error of the calculated vehicle behavior;
Driving force target value determining means for determining a driving force target value of each wheel by the sum of the driving force basic value and the calculated driving force correction amount;
A driving force distribution device for a four-wheel independent drive vehicle, comprising: driving force control means for controlling the driving force of each wheel so as to obtain the determined driving force target value of each wheel. In vehicles that can drive all four wheels independently,
Vehicle behavior target value determining means for determining a target value of the vehicle longitudinal force of the vehicle and a target value of the vehicle lateral force as a target value of the vehicle behavior;
Driving force basic value setting means for setting the driving force basic value of each wheel;
Vehicle behavior basic value calculation means for calculating the basic value of the vehicle longitudinal force realized by the set driving force basic value of each wheel and the basic value of the vehicle lateral force as the basic value of the vehicle behavior;
Vehicle behavior error calculating means for calculating an error between the target value of the vehicle behavior and the calculated basic value of the vehicle behavior as an error of the vehicle behavior;
Driving force correction amount calculating means for calculating the driving force correction amount of each wheel for reducing the error of the calculated vehicle behavior;
Driving force target value determining means for determining a driving force target value of each wheel by the sum of the driving force basic value and the calculated driving force correction amount;
A drive force distribution device for a four-wheel independent drive vehicle, comprising: drive force control means for controlling the drive force of each wheel so that the determined drive force target value of each wheel is obtained. A driving force recorrection amount calculating means for calculating a driving force recorrection amount of each wheel that changes the vehicle lateral force within a range of a predetermined amount of error from zero;
9. A driving force target value resetting unit for resetting a value obtained by adding the calculated driving force recorrection amount to the driving force target value as the driving force target value again. The drive power distribution device for the four-wheel independent drive vehicle described. The driving force recorrection amount calculating means includes
Driving force maximum value setting means for setting the driving force maximum value of each wheel;
A vehicle lateral force changeable amount that calculates an amount by which the vehicle lateral force can be changed within a range of the predetermined amount from zero based on the driving force target value and the set driving force maximum value. Computing means;
11. The four-wheel independent vehicle according to claim 10, further comprising: a driving force recorrection amount setting unit that sets a driving force correction amount of each wheel that changes the lateral force of the vehicle as the driving force recorrection amount. Driving force distribution device for driving vehicles. Driving force recorrection amount calculating means for calculating a driving force recorrection amount of each wheel that changes the yaw moment within a range of a predetermined amount from zero;
The driving force target value resetting means which resets a value obtained by adding the calculated driving force recorrection amount to the driving force target value as the driving force target value again. The drive power distribution device for the four-wheel independent drive vehicle described. The driving force recorrection amount calculating means includes
Driving force maximum value setting means for setting the driving force maximum value of each wheel;
Based on the driving force target value and the set driving force maximum value, a yaw moment changeable amount calculating means for calculating an amount capable of changing the yaw moment within a range of the predetermined amount from zero;
The four-wheel independent drive vehicle according to claim 12, further comprising driving force recorrection amount setting means for setting a driving force correction amount of each wheel that changes the yaw moment as the driving force recorrection amount. Drive power distribution device.

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