JPH10287146A - Vehicle motion control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the steerablity of a vehicle in response to handle operations at all times, avoid axcessive under-steering/over-steering caused when the vehicle is turned around, and thereby enhance the running performance of the vehicle. SOLUTION: A control unit 29 is formed out of a revolving moment arithmetic circuit 30, and of an output signal setting circuit 31, and the revolving arithmetic operating circuit 30 is formed out of a first proportion operating circuit 32, a second proportion operating circuit 33, and of a revolving moment computing circuit 34. And the revolving moment arithmetic circuit 30 is connected with a revolving angular speed sensor 27 and a steering angle sensor 28, and computes the revolving moment which must be given to the vehicle in proportion to both the revolving angular speed and the steering angle. Besides, the output signal setting circuit 31 sets up a control signal to be outputted to a motor control part 25 based on the revolving moment computed by the revolving moment arithmetic circuit 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle motion control device for automatically controlling the running of a vehicle by detecting the steering angle and the turning angular velocity of the vehicle, and in particular, to avoid excessive understeer or oversteer occurring when the vehicle turns. Left,
The present invention relates to a vehicle motion control device that automatically controls distribution of a driving force applied to a right wheel.

[0002]

2. Description of the Related Art When a vehicle turns, depending on the road surface condition, the speed of the vehicle, and the like, the actual turning radius of the vehicle may be understeer larger than the target turning radius, or the actual turning radius of the vehicle may become larger than the target turning radius. Small oversteer may occur with respect to the turning radius. In some cases, it is difficult to avoid such excessive understeer and oversteer only by operating the steering wheel by the driver.

Therefore, the distribution of the driving force applied to the left and right driving wheels is automatically controlled based on the operation of the steering wheel by the driver,
A vehicle motion control device that avoids understeer and the like generated when the vehicle turns is described in, for example, a public relations document “Left and right driving force distribution system” issued by Honda Motor Co., Ltd. on May 29, 1996. Are known.

In the vehicle motion control apparatus according to the prior art, the amount of turning around the vertical axis of the center of gravity of the vehicle is determined from the steering angle of the steering wheel and the lateral acceleration of the vehicle body, and the turning amount is multiplied by the engine driving force. The driving force is distributed to the left and right wheels based on the calculation result, and the turning moment is variably controlled.

[0005]

Generally, regardless of whether the vehicle is accelerating or decelerating, the tire generating force (determined by the braking force, the driving force, the cornering power, etc.) is determined by the radius of the friction circle of the tire (the ground contact load of the tire). The vehicle may exhibit excessive understeer or excessive oversteer in a vehicle running state (vehicle running state in a tire limit area) approaching the tire generation force limit value determined by the road friction and the road surface friction. The prior art described above aims at avoiding understeer which occurs mainly when the vehicle is accelerated.

[0006] However, understeer may occur when the vehicle is traveling at a constant speed or deceleration, or when the vehicle is traveling at a high speed. In such a case, the vehicle motion control device according to the related art can avoid understeer that occurs during acceleration of the vehicle, but excessive understeer when the vehicle is traveling at a constant speed or deceleration, or when the vehicle is traveling at high speed. However, there is a problem that it is difficult to effectively avoid oversteer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and effectively avoids excessive understeer and oversteer that occur when the vehicle turns other than when the vehicle is accelerating, thereby improving the traveling performance of the vehicle. It is an object of the present invention to provide a vehicle motion control device capable of performing such operations.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a driving force applying means provided on a vehicle body for applying different driving forces to left and right wheels, and the driving force applying means. The present invention is applied to a vehicle motion control device including driving force distribution means for distributing driving force to be applied to left and right wheels in accordance with a control signal in order to operate.

A feature of the configuration adopted by the invention of claim 1 is that the driving force distribution means detects a turning angular velocity Ψ about a vertical axis of a center of gravity of the vehicle,
Steering angle detection means for detecting the steering angle δ of the vehicle, a vehicle in proportion to a detection signal of the turning angular velocity 出力 outputted from the turning angular velocity detection means and a detection signal of the steering angle δ outputted from the steering angle detection means. A turning moment amount calculating means for calculating a turning moment amount M to be applied to the vehicle, and an output signal for setting a control signal to be output to the driving force applying means based on the turning moment amount M calculated by the turning moment amount calculating means. And a setting unit.

With this configuration, the turning moment amount M is calculated by the turning moment amount calculating means based on the detection signal of the turning angular velocity Ψ from the turning angular velocity detecting means and the detection signal of the steering angle δ from the steering angle detecting means. Is calculated, and the output signal setting means outputs a control signal to the driving force applying means so as to generate the turning moment amount M.

Thus, the driving force applying means can apply different driving forces to the left and right wheels, and can apply a turning moment M proportional to the turning angular velocity 旋回 and the steering angle δ to the vehicle.

According to the second aspect of the present invention, the turning moment amount calculating means calculates a _first calculation value S ₁ corresponding to the turning angular velocity 基 づ き based on a detection signal output from the turning angular velocity detecting means. Based on a detection signal output from the steering angle detecting means and a second calculating means corresponding to the steering angle δ.
A second proportional operation means for calculating an operation value S ₂ of
First subtracting the calculation values S ₁ according to the first proportional calculation means second from the arithmetic value S ₂ by the proportional calculation means, the turning moment amount to calculate the turning moment amount M as M = S ₂ -S ₁ And calculation means.

With this configuration, the turning moment amount calculating means can calculate the second calculated value S corresponding to the steering angle δ.
By subtracting the first calculation value S ₁ corresponding to the turning angular velocity ₂ from ₂ and calculating the turning moment M as M = S ₂ −S ₁ , the turning moment M is increased in proportion to the steering angle δ. And the amount of turning moment M is proportional to the turning angular velocity Ψ.
Decrease. In other words, the turning moment M generates a moment in the direction opposite to the turning angular velocity Ψ.

Thus, the output signal setting means outputs a control signal to the driving force applying means so as to generate the turning moment M, and the driving force applying means applies different driving forces to the left and right wheels. This can attenuate the turning angular velocity Ψ of the vehicle and turn the vehicle in proportion to the steering angle δ.

Further, in the invention according to claim 3, the output signal setting means sets the steering angle δ in the left turning direction to δ> 0, sets the steering angle δ in the right turning direction to δ <0, and turns the vehicle in the left turning direction. Angular velocity Ψ
> 0, when the turning angular velocity 右 in the right turning direction is Ψ <0, when the turning moment M is M> 0, the driving force applied to the left wheel is reduced, and the driving force applied to the right wheel is reduced. A control signal for increasing the force is output, and when the turning moment M is M <0, the control signal for increasing the driving force applied to the left wheel and decreasing the driving force applied to the right wheel. Is output.

With this configuration, for example, when understeer occurs during a left turn, the first proportional operation means outputs the first operation value S ₁ corresponding to the turning angular velocity Ψ, and outputs the second proportional value. The calculating means calculates the second calculated value S ₂ corresponding to the steering angle δ that is larger than the first calculated value S _1.
(S ₂ > S ₁ ) is output. Then, the turning moment amount calculation means outputs a positive turning moment amount M (M> 0) from the first operation value S ₁ and the second operation value S ₂ .

Thus, the output signal setting means determines that the vehicle is in an understeer state during a left turn, and reduces the driving force applied to the left wheel and increases the driving force applied to the right wheel. Output a signal. The driving force applying means applies a turning moment in the left turning direction to the vehicle according to the control signal.

For example, when oversteering occurs during a left turn, the first proportional operation means outputs a _first operation value S ₁ corresponding to the turning angular velocity Ψ, and the second proportional operation means outputs the first operation value S 1. And outputs a _second calculated value S ₂ (S ₂ <S ₁ ) corresponding to the steering angle δ that is smaller than the calculated value S ₁ .
Then, the turning moment amount calculating means calculates the first calculated value S
₁ and the turning moment amount M of the second calculation value S ₂ from a negative value
(M <0) is output.

Thus, the output signal setting means determines that the vehicle is in an oversteer state during a left turn, and increases the driving force applied to the left wheel and decreases the driving force applied to the right wheel. Output a signal. Then, the driving force applying means applies a turning moment in the right turning direction to the vehicle according to the control signal.

For example, when understeer occurs during a right turn, the first proportional operation means outputs a _first operation value S ₁ corresponding to the turning angular velocity Ψ, and the second proportional operation means The second calculated value S ₂ (S ₂ <S ₁ ) corresponding to the steering angle δ that is smaller than the calculated value S _{1 of 1} is output.
Then, the turning moment amount calculating means calculates the first calculated value S
₁ and the turning moment amount M of the second calculation value S ₂ from a negative value
(M <0) is output.

Thus, the output signal setting means determines that the vehicle is in an understeer state during a right turn, and increases the driving force applied to the left wheel and decreases the driving force applied to the right wheel. Outputs control signal. Then, the driving force applying means applies a turning moment in the right turning direction to the vehicle according to the control signal.

Further, for example, when oversteer occurs during a right turn, the first proportional operation means sets the turning angular velocity Ψ
Outputting a first calculation values S ₁ corresponding to the second proportional calculation means, the steering angle as a first value larger than the calculation values S ₁ [delta]
Is output as the second operation value S ₂ (S ₂ > S ₁ ). Then, the turning moment amount calculation means outputs a positive turning moment amount M (M> 0) from the first operation value S ₁ and the second operation value S ₂ .

With this, the output signal setting means determines that the vehicle is in an oversteer state during a right turn, and reduces the driving force applied to the left wheel and increases the driving force applied to the right wheel. Outputs control signal. The driving force applying means applies a turning moment in the left turning direction to the vehicle according to the control signal.

Further, in the invention according to claim 4, the first proportional computing means computes the first computed value S ₁ as S ₁ = α ₁ × 但 (provided that a proportional constant satisfying α ₁ > 0). The second proportional calculation means is configured to calculate the second calculated value S ₂ as S ₂ = α ₂ × δ (where α ₂ ≧ 5 × α _{1 is} a proportional constant).

With the above configuration, the turning moment amount calculating means calculates the second calculated value S ₂ from S ₂ = α ₂ × δ.
_{The first} operation value S ₁ of ₁ = α ₁ × Ψ is subtracted, and the turning moment M is calculated as M = S ₂ −S ₁ .

With this, the output signal setting means sets the understeer state during, for example, a left turn to (α ₂ × δ)> (α ₁ ×
The judgment is made when Ψ), and a control signal for turning the vehicle to the left is output. The driving force applying means applies a turning moment in the left turning direction to the vehicle according to the control signal.

The output signal setting means determines, for example, the oversteer state when turning left when (α ₂ × δ) <(α ₁ × Ψ), and outputs a control signal for turning the vehicle to the right. Output. Then, the driving force applying means applies a turning moment in the right turning direction to the vehicle according to the control signal.

The output signal setting means determines, for example, the understeer state when turning right when (α ₂ × δ) <(α ₁ × Ψ), and outputs a control signal for turning the vehicle right. Is output. Then, the driving force applying means applies a turning moment in the right turning direction to the vehicle according to the control signal.

The output signal setting means determines, for example, the oversteer state when turning right when (α ₂ × δ)> (α ₁ × Ψ), and outputs a control signal for turning the vehicle to the left. Output. The driving force applying means applies a turning moment in the left turning direction to the vehicle according to the control signal.

According to the fifth aspect of the present invention, assuming that the moment of inertia about the vertical axis of the center of gravity of the vehicle is I, the proportional constant α ₁ of the first proportional calculation means is set to α ₁ ≧ (2/3) × I. Is set in advance, and the proportionality constant α ₂ of the second proportional operation means is α
₂ ≧ (10/3) × I is set in advance.

[0031] With the above configuration, the first proportional operation means includes:
| S ₁ | ≧ (2/3) × I × corresponding to the moment of inertia I
Outputs a _first operation value S ₁ that satisfies | Ψ |, and the second proportional operation means outputs a second operation value that satisfies | S ₂ | ≧ (10/3) × I × | δ |
And outputs the calculated value S _2. Then, the turning moment amount calculating means calculates the turning moment amount M as M = S ₂ −S ₁ according to the inertia moment I.

Thus, the output signal setting means outputs a control signal to the driving force applying means so as to generate the turning moment M according to the inertia moment I, and the driving force applying means outputs the control signal to the left and right wheels. By applying different driving forces to each other, it is possible to apply an optimum turning moment to the vehicle according to the weight, shape, and the like of the vehicle, and it is possible to improve the steerability and traveling performance of the vehicle.

[0033] In the invention according to claim 6, the driving force is applied.
The provision means depends on the propulsion axis. Differential rotated
Actuator that transmits the torque of the case to the left and right wheel axles
And one of the left and right wheel axles incorporated in the actuator.
Relative rotation between the side and the differential case side.
And a rotation source for applying a rolling force.

Thus, by controlling the rotation direction and the rotation torque of the rotation source, the ratio of the distribution of the driving force to the left and right wheel shafts can be positively controlled.

[0035]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 to 3 show an example in which the vehicle motion control apparatus according to the embodiment of the present invention is applied to a front-wheel drive vehicle.

First, the driving force applying means of the vehicle motion control device according to the present embodiment will be described with reference to FIGS.

In the figure, reference numeral 1 denotes a vehicle body having an engine (not shown) as a drive source mounted thereon and capable of running on its own,
The vehicle body 1 has left and right front wheels 2 and 3 and left and right rear wheels 4 and 5.
The front wheels 2 and 3 are steered by a steering device 6. The vehicle body 1 has a power storage device 2 described later.
4 and a motor control unit 25 together with a differential device 7 which constitutes a driving force applying means. The differential device 7 is connected to the engine via a propulsion shaft 8 and is also provided via a wheel shaft 9, 10. It is connected to the wheels 4 and 5 and transmits the driving force from the engine to the rear wheels 4 and 5.

As shown in FIG. 2, the differential device 7 generally includes a differential housing 11 as a main body of the differential device 7 and a differential case 12 provided in the differential housing 11. Then, the differential device 7 transmits the torque of the propulsion shaft 8 to the differential case 12 via the reduction gear 13 and the reduction gear 14, and differentially transmits the torque of the differential case 12 to the differential gear 15. The gears 16, 17 distribute equally to the left and right wheel shafts 9, 10. In addition, the differential device 7 rotates the wheel shafts 9 and 1 by the rotation of the differential small gear 15.
It absorbs a rotation speed difference of zero. Thus, the differential device 7
Transmits the rotational force of the differential case 12 rotated by the propulsion shaft 8 to the wheel shafts 9 and 10.

Reference numeral 18 denotes an electric motor as a rotation source incorporated in the operating device 7. The electric motor 18 is provided in the differential housing 11, and rotates relatively between the left wheel shaft 9 and the differential case 12. It is constituted by a DC motor or the like capable of applying a force. Also,
The electric motor 18 has a stator 19 fitted and fixed inside the differential case 12, and a rotor 20 located on the inner peripheral side of the stator 19 and fitted and fixed to the left wheel shaft 9.
The rotor 20 is provided so as to be relatively rotatable in the forward and reverse directions with respect to the stator 19, and its rotational torque changes according to the drive current.

A generator 21 is provided in the differential housing 11 and generates electric power by rotation of the differential case 12. The generator 21 includes a stator 22 fitted and fixed inside the differential housing 11, And a rotor 23 which is located on the circumferential side and fitted and fixed to the differential case 12.

Reference numeral 24 denotes a power storage device that is connected to the generator 21 and stores the electric energy generated by the generator 21. The power storage device 24 is connected to the electric motor 18 via a motor control unit 25 and a slip ring 26. The electric energy in the power storage device 24 is supplied to the electric motor 18.

Reference numeral 25 denotes a motor control unit for controlling the drive of the electric motor 18 in accordance with a control signal output from a control unit 29 described later. The motor control unit 25 controls the forward and reverse rotation directions and the rotational torque of the electric motor 18. I do.

Reference numeral 26 denotes an electric motor 18 and a motor control unit 25.
And a slip ring 26 which is electrically connected at all times. The slip ring 26 is made up of a pair of ring members which are in sliding contact with each other. One ring member is provided in the differential housing 11 and the other ring member is provided in the differential case 12. Have been. The slip ring 26 is interposed in a circuit between the electric motor 18 on the rotating differential case 12 side and a fixed-side motor control unit 25 provided for external localization.

Here, the operation of the differential device 7 will be described. The generator 21 is driven by the rotation of the differential case 12, and the generated electric energy is stored in the power storage device 24. The motor control unit 25 receives the signal from the control unit 29 and
Is driven.

Then, the electric motor 18 is driven to rotate in one direction, and the inner rotor 2 is
If 0 is forcibly rotated in the direction of increasing the speed of the left wheel shaft 9, the left wheel shaft 9 is accelerated and the right wheel shaft 10 is decelerated by the relative rotation therebetween. ,
A turning moment in the right turning direction is generated in the vehicle. Also, the rate of acceleration / deceleration of these wheel shafts 9, 10
That is, the ratio of the distribution of the driving force is continuously adjusted by the motor control unit 25 controlling the rotation torque of the electric motor 18.

On the other hand, the electric motor 18 is driven to rotate in the other direction, and the inner rotor 20 is
Is forcibly rotated in a direction for decelerating the left wheel axle 9, the left wheel axle 9 is rotated by a relative rotation therebetween.
Is decelerated, the right wheel shaft 10 is accelerated, and a turning moment in the left turning direction is generated in the vehicle. Further, the rate of acceleration / deceleration of these wheel shafts 9, 10, that is, the rate of distribution of the driving force, is continuously adjusted by the motor control unit 25 controlling the rotation torque of the electric motor 18.

As described above, the control unit 29 controls the motor control unit 25 according to the running state such as when the vehicle is turning, so that the ratio of the distribution of the driving force to the left and right wheel shafts 9 and 10 is positively controlled. Control, the turning moment of the vehicle can be controlled, and the traveling performance at the time of turning of the vehicle and the like can be improved. Also, since the electric motor 18 is incorporated in the operating device 7, the operating device 7
Can be reduced in size and weight. Further, since the operation device 7 can have a simple configuration, the cost of the entire device can be reduced.

Next, the driving force distribution means of the vehicle motion control device according to this embodiment will be described with reference to FIGS.

Reference numeral 27 denotes a turning angular velocity sensor for detecting a turning angular velocity about the vertical axis of the center of gravity of the vehicle. The turning angular velocity sensor 27 is constituted by an angular velocity sensor for detecting Coriolis force such as a tuning fork type strain gauge. Is provided at the position of the center of gravity. The turning angular velocity sensor 27 detects a turning angular velocity Ψ in the left turning direction as Ψ> 0, detects a turning angular velocity 右 in the right turning direction as Ψ <0, and outputs a detection signal corresponding to the turning angular velocity Ψ. I do.

Numeral 28 denotes a steering angle sensor which is provided, for example, in the steering device 6 and detects steering angle δ of the vehicle from the rotation angle θ of the steering wheel.
Reference numeral 8 denotes an optical sensor using a phototransistor or the like, a potentiometer, or the like. The steering angle sensor 28 detects the steering angle δ of the vehicle as, for example, a quotient of the steering gear ratio N with respect to the rotation angle θ (δ = θ / N). The steering angle sensor 28 detects a steering angle δ in the left turning direction as δ> 0, detects a steering angle δ in the right turning direction as δ <0, and outputs a detection signal corresponding to the steering angle δ. I do.

Reference numeral 29 denotes a control unit which constitutes driving force distribution means together with the turning angular velocity sensor 27 and the steering angle sensor 28. The control unit 29 comprises a microcomputer or the like, and calculates a turning moment amount as turning moment amount calculating means. It comprises a circuit 30 and an output signal setting circuit 31 as output signal setting means. A turning angular velocity sensor 27 and a steering angle sensor 28 are connected to the input side of the turning moment amount calculation circuit 30,
The motor control unit 25 is connected to the output side of the output signal setting circuit 31.

In addition, the turning moment amount calculation circuit 30
First proportional operation circuit 32, second proportional operation circuit 3, which will be described later.
3. A turning moment amount calculating circuit 34 is provided to the vehicle in proportion to the turning angular velocity Ψ detection signal output from the turning angular velocity sensor 27 and the steering angle δ detection signal output from the steering angle sensor 28. The power turning moment amount M is calculated. The output signal setting circuit 31 sets a control signal to be output to the motor control unit 25 based on the turning moment amount M by the turning moment amount calculation circuit 30.

Reference numeral 32 denotes a first proportional operation circuit as first proportional operation means. The first proportional operation circuit 32 corresponds to the turning angular velocity 基 づ き based on the detection signal of the turning angular velocity 出力 outputted from the turning angular velocity sensor 27. to and calculates, as shown in the first equation of calculation values S ₁ number 1 below.

[0055]

[Equation 1] S ₁ = α ₁ × Ψ

Here, the proportionality constant α ₁ is a positive value (α ₁ >
0), which is preset to a value of about α ₁ = (２) × I with respect to the moment of inertia I about the vertical axis of the center of gravity of the vehicle. Further, the proportionality constant α ₁ has a relationship of the following equation 2 with the moment of inertia I.

[0057]

(Equation 2)

Reference numeral 33 denotes a second proportional operation circuit as second proportional operation means. The second proportional operation circuit 33 corresponds to the steering angle δ based on the detection signal of the steering angle δ output from the steering angle sensor 28. the second calculated value S ₂ and calculates as shown in the following equation (3) to be.

[0059]

[Equation 3] S ₂ = α ₂ × δ

Here, the proportionality constant α ₂ has the following relationship with the proportionality constant α ₁ in the following equation (4).

[0061]

[Equation 4] α ₂ ≧ 5 × α ₁

Accordingly, the proportionality constant α ₂ is calculated from the equations (2) and (4) as α
_It is preset to a value of about ₂ = (10/3) × I.

Reference numeral 34 denotes a turning moment amount calculating circuit as turning moment amount calculating means. The turning moment amount calculating circuit 34 converts the second operation value S ₂ by the second proportional operation circuit 33 into a first proportional operation circuit. 32 first subtracts the calculation values S ₁ by a turning moment amount M is calculated as shown in the following equation equation 5.

[0064]

M = S ₂ −S ₁ = α ₂ × δ−α ₁ × Ψ

The output signal setting circuit 31 reduces the driving force applied to the left wheel shaft 9 when the turning moment M is a positive value (M> 0) and applies the driving force to the right wheel shaft 10. A control signal for increasing the driving force is output, and when the turning moment M is a negative value (M <0), the driving force applied to the left wheel shaft 9 is increased, and the right wheel shaft 10 is increased.
And outputs a control signal for reducing the driving force applied to the control signal. Thereby, the motor control unit 25 controls the electric motor 18
Change the forward and reverse rotation directions and the rotation torque of the wheel shafts 9 and 1
0 is increased or decreased, and the turning moment of the vehicle is controlled.

The output signal setting circuit 31 does not need to distribute the driving force to the wheel shafts 9 and 10 when the turning moment M is zero (M = 0). And outputs a control signal for stopping the operation. Thereby, the motor control unit 25 controls the electric motor 1
The supply of current to 8 is stopped.

The vehicle motion control device according to the present embodiment has the above-described configuration, and its operation will be described next with reference to FIG.

FIG. 4 shows a two-wheeled vehicle model in which a four-wheeled vehicle is replaced by an equivalent two-wheeled vehicle, in which front wheels 2 and 3 are replaced by one front wheel 35 and rear wheels 4 and 5 are replaced by one. Are replaced by rear wheels 36. The vehicle motion in the lateral direction (Y direction) when the vehicle is controlled by the vehicle motion control device of the present embodiment has the relationship shown in the following Expression 6.

[0069]

(Equation 6) However, m: vehicle mass V: vehicle speed beta: slip angle F _1: front wheel cornering force F _2: rear wheel cornering force

Here, the sideslip angular velocity (dβ / dt) is an angular velocity with respect to the sideslip angle β as an angle between the traveling direction of the vehicle (the direction of the vehicle speed V) and the longitudinal direction of the vehicle body 1. In addition, the cornering force F ₁ of the front wheel is a front wheel 2,
Y caused by the deformation of No. 3 occurring on the contact surface of the road surface
Is the direction of the force, cornering force F ₂ of the rear wheels is the Y direction of the force caused by the deformation of the rear wheels 4 and 5 occurs on the contact surface of the road. Further, cornering force F ₁ of the front wheel between the side slip angle beta ₁ and the front wheel cornering power C ₁ of the front wheels, a relationship of the following Expression 7.

[0071]

## EQU7 ## F ₁ = C ₁ × β ₁

The cornering force F ₂ of the rear wheel has the following equation 8 between the side slip angle β ₂ of the rear wheel and the cornering power C _{2 of the} rear wheel.

[0073]

[Equation 8] F ₂ = C ₂ × β ₂

Here, the sideslip angle β ₁ of the front wheels and the sideslip angle β _{2 of the} rear wheels have the following relationship with the sideslip angle β in the following equation (9).

[0075]

(Equation 9) Where a is the center of gravity O and the center of rotation O1 -O of the front wheels 2 and 3.
B: Distance between center of gravity O and center of rotation O2 -O2 of rear wheels 4, 5

Further, from the expressions of the expressions 7 to 9, the expression of the expression 6 can be replaced with the expression of the following expression 10.

[0077]

(Equation 10)

The motion of the vehicle in the turning direction (Ψ direction) about the vertical axis of the center of gravity of the vehicle has a relationship with the turning moment amount M as shown in the following equation (11).

[0079]

[Equation 11]

When the vehicle is rewritten using the Laplace operator s based on the equations (10) and (11), the vehicle can be represented by a second-order lag system, and the vehicle shows the rate at which the turning angular velocity 変 化 changes according to the steering angle δ. the transfer function H _V of the relation of the following Expression 12.

[0081]

(Equation 12) Where K _r : coefficient _Tr : coefficient ω ₀ : coefficient 2ζ ₀ ω ₀ : coefficient

Here, the coefficient K _r in the equation (12) is a numerical value indicating the gain of the turning angular velocity に 対 す る with respect to the steering angle δ.
There is a relationship shown in FIG.

[0083]

(Equation 13) Where L: constant K _S : coefficient

In the equation (13), the constant L is the distance between the rotation centers O1 -O1 of the front wheels 2 and 3 and the rotation centers O2 -O2 of the rear wheels 4 and 5, and the coefficient K _S is expressed by the following equation (14). Have a relationship.

[0085]

[Equation 14]

[0086] In addition, in the number 12, each coefficient T _r, 2ζ ₀ ω
₀ and ω ₀ have the following relationship, respectively.

[0087]

(Equation 15)

Further, the lateral acceleration during running increases, and the front wheels 3
5. At the time of the tire limit (or when approaching the time of the tire limit) at which the rear wheel 36 slips, the cornering power C _{1 of the} front wheel and the cornering power C _{2 of the} rear wheel become
It is thought that it becomes.

[0089]

## EQU16 ## C ₁ = C ₂ = 0

As described above, the cornering power C of the front wheel
_1, the cornering power C ₂ of the rear wheels is zero (C ₁ = C ₂ =
0), the transfer function H _V of the vehicle at this time becomes
Expression 16 can be replaced by Expression 17 below, and the vehicle can be represented as a first-order lag system.

[0091]

[Equation 17] Where _Km : coefficient _Tm : time constant

At this time, the coefficient K _m and the time constant T _m have the relations of Expressions 18 and 19, respectively.

[0093]

(Equation 18)

[0094]

[Equation 19]

[0095] Here, the coefficient K _m is a numerical value indicating the gain of the turning angular velocity Ψ for δ the steering angle, the change in turning angular velocity Ψ increases relative as steering angle δ coefficient K _m is large. The time constant _Tm is 63% of the target turning angular velocity of the vehicle.
And a constant corresponding to a response delay of the vehicle until the turning angular velocity 変 化 changes according to the steering. Then, time constant T _m response of the vehicle is slow with respect to the turning direction is too large, the steering resistance is deteriorated. Therefore, by presetting the proportional constants α ₁ and α ₂ so as to increase the coefficient K _m and decrease the time constant T _m , the turning angular velocity 制 御 can be freely controlled by operating the steering wheel even at the time of the tire limit. It was confirmed that it was possible.

Next, the effects of the proportional constants α ₁ and α ₂ on the vehicle will be described.

First, the effect on the proportionality constant α ₁ will be described. When a vehicle enters a curve of a road, the driver is required to measure the deviation of the road from the traveling direction (V1 direction) just before the curve as shown in FIG. e, and distance dimension L1
The steering angle δ to be given to the vehicle just before is determined. In this manner, the driver and the vehicle constitute a feedback control system that reduces the road deviation dimension e as shown in FIG. At this time, the driver's transfer function H _S from when the driver visually recognizes the deviation dimension e to when the driver operates the steering wheel corresponding to the steering angle δ.
Has the relationship of the following equation (20).

[0098]

(Equation 20) Where G: driver's steering gain T _S : driver's time constant T _P : preview time

Here, the steering gain G of the driver is a constant corresponding to the operation amount when the driver operates the steering wheel, and the time constant T _S of the driver is the steering wheel gain after the driver visually recognizes the deviation dimension e. This is a constant corresponding to the response delay before the operation.
The time T _P foreseen is the time required to pass through a position visible from the viewing dimensions e shift the driver, the following equation between the distance dimension L1 and the vehicle speed V1 to the viewing position 21 There is a relationship.

[0100]

## EQU21 ## T _P = L1 / V1

Further, the transfer function H _V of the vehicle at the time of the tire limit is obtained.
Since there is a relationship shown in the equation (17), the overall transfer function including the driver and the vehicle has a relationship shown in the following equation (22) from the equations (17) and (20).

[0102]

(Equation 22)

Here, for a normal driver, the preview time T _P
It is known that, as disclosed in, for example, “Automotive Technology Vol. 49, No. 12,” p.

[0104]

[Equation 23] 0.5 seconds ≦ _TP ≦ 2.0 seconds

That is, when the preview time T _P is 2 seconds (T _P =
2) is the limit of visibility when the driver is gazing at a distance, and when the preview time T _P is 0.5 seconds (T _P = 0.5)
Is a limit of a time margin for appropriately determining an operation amount or the like.

The time constant T _S of the driver is 0.1 seconds (T
_Since it is generally known that the value becomes as small as about _S = 0.1), if the time constant T _S of the driver is set to zero (T _S ≒ 0), the equation of Equation 22 becomes the equation of Equation 24 below. Can be replaced as

[0107]

(Equation 24)

[0108] Thus, as shown in FIG. 7, it can be confirmed that has a configuration that can be compensated by predicting time T _P of the response delay of the vehicle until the change of the turning angular velocity Ψ according to the driver's handle operation . That is, when there is no response delay of the vehicle and the turning angular velocity 車 両 of the vehicle changes immediately in response to the driver's operation of the steering wheel, the driver operates the vehicle 2 to 0.5 seconds before reaching the curve. By judging the amount, the vehicle can be driven to be displaced by the deviation dimension e of the curve, but there is a response delay of the vehicle, and the turning angular velocity of the vehicle with respect to the steering wheel operation of the driver Ψ
If the change of delay would constant T _m by foreseeing time T _P when corresponds to the constant T _m when the vehicle is reduced.

Here, the time constant T _m according to the present embodiment is given by
From equation (9), it is a constant that depends on the proportionality constant α ₁ and the moment of inertia I. Further, since the proportionality constant α ₁ has a relationship expressed by Equation 2 with the moment of inertia I, the time constant T _m is 1.5
Seconds or less (T _m ≦ 1.5). Therefore, the preview time T
_P is 0.5 seconds or more, which is the limit of the time margin (T _P ≧ 0.
5), and the response delay of the vehicle can be predicted for the foreseeing time T _P
It was confirmed that the driver could operate the steering wheel of the vehicle by compensating for this.

Next, the operation of the proportionality constant α ₂ will be described. The proportionality constant α ₂ is related to the coefficient K _m indicating the gain of the turning angular velocity に 対 す る with respect to the steering angle δ at the time of the tire limit, as shown in the equation (18). Is a constant. As can be seen from Equations ( ₁₂ ) and (17), the coefficient K _m is calculated based on the cornering force F ₁ (F ₂ ) and the side slip angle β ₁ (β
₂ ) is a constant corresponding to a coefficient K _r indicating the gain of the turning angular velocity に 対 す る with respect to the steering angle δ in the tire linear range, which is substantially proportional to the steering angle δ.
The coefficient K _m according to the present embodiment is 5 or more (K _m ≧ 5) from the relationship of Expressions 18 and 4.

Here, the coefficient K _r is 1 in the linear region of the tire.
It is known that it is about 0 (K _r = 10). Then, the coefficient K _r is very small as compared with 10 (K _r ≪1
0), the change in the turning angular velocity に 対 す る with respect to the steering angle δ becomes small, and the vehicle does not easily turn, so that the steerability of the vehicle deteriorates. However, in general it is known that the coefficient K _r are possible steering of the vehicle by steering operation if more than half of the tire linear region, the coefficient K _m at more than half the value of the coefficient K _r of the tire linear range Therefore, in this example, it was confirmed that the vehicle could be steered even at the time of the tire limit.

Next, the response characteristics of the turning angular velocity に 対 す る to the steering angle δ will be described. First, the cornering power C _{1 of the} front wheel and the cornering power C _{2 of the} rear wheel are determined as follows, and the following equation is satisfied with respect to the cornering power C ₁₀ of the front wheel and the cornering power C _{20 of the} rear wheel on a dry road surface. I do.

[0113]

C ₁ = λ × C ₁₀ C ₂ = λ × C ₂₀ where λ: reduction coefficient

Here, the decrease coefficient λ is a constant in the range of 0 to 1 (0 ≦ λ ≦ 1), and the smaller the decrease coefficient λ, the more the vehicle is likely to cause a relatively large side slip, ie, the tire This indicates that the state is near the limit.

Each proportional constant α is used as a response characteristic of a conventional vehicle.
FIGS. 8 and 9 show a comparative example in which ₁ and α ₂ are set to zero (α ₁ = α ₂ = 0). The characteristic lines 37 and 38 shown in FIG.
Numerals 39 and 40 denote gains of the turning angular velocity に 対 す る of the vehicle with respect to the frequency of the steering wheel operation, and correspond to the amount of change in the traveling direction of the vehicle when the steering wheel operation for steering the vehicle in the left and right directions is performed at a constant cycle. It is. Also, the case where the steering wheel is operated more rapidly as the frequency is higher is shown, and the case where the steering wheel is operated more slowly as the frequency is lower is shown.

The characteristic lines 37, 38, 39, and 40 show the cases where the reduction coefficient λ is 0.001, 0.01, 0.1, and 1.0, respectively. It is known that a high frequency range when a general driver performs steering is 1 to 10 rad / sec. However, at the time of the tire limit, the gain hardly occurs in this frequency range. That is, in the case of the conventional vehicle, the transfer function H of the vehicle at the time of the tire limit is expressed by the equation (17).
_V becomes zero (H _V = 0), and the turning angular velocity 変 化 does not change with respect to the steering angle δ. Therefore, at the time of the tire limit, the vehicle cannot be steered by operating the steering wheel.

The characteristic lines 41, 42, 43,
Reference numeral 44 denotes the phase of the vehicle with respect to the frequency of the steering operation, and corresponds to the operation delay of the vehicle when the steering operation for steering the vehicle in the left and right directions is performed at a constant cycle. The characteristic lines 41, 42, 43, and 44 show the cases where the reduction coefficient λ is 0.001, 0.01, 0.1, and 1.0, respectively. In a high frequency frequency range (1 to 10 rad / sec) when a general driver steers, the phase is also delayed to the limit, so that the turning angular velocity 車 両 of the vehicle cannot be changed quickly by operating the steering wheel. It was confirmed that the change in the traveling direction of the vehicle with respect to the operation was extremely delayed, and the responsiveness of the vehicle was extremely poor, so that it was practically impossible to steer the vehicle.

On the other hand, the characteristics of the vehicle according to the present embodiment are shown in FIG.
0, shown in FIG. Characteristic lines 45, 46, and 4 shown in FIG.
Reference numerals 7 and 48 denote gains of the turning angular velocity Ψ of the vehicle with respect to the frequency of the steering wheel operation, and the reduction coefficient λ is 0, 0.01, 0.
Cases at 1 and 1.0 are shown. At this time, in the frequency range of 1 to 10 rad / sec, a gain of the turning angular velocity Ψ can be obtained even at the time of the tire limit (λ = 0). Therefore, the turning angular speed Ψ of the vehicle changes according to the operation of the steering wheel, and the driver can turn the vehicle.

The characteristic lines 49, 50, 5 in FIG.
Numerals 1 and 52 indicate the phases of the vehicle with respect to the frequency of the steering wheel operation, and show cases where the reduction coefficient λ is 0, 0.01, 0.1 and 1.0, respectively. At this time, 1-10r
In the frequency range of ad / sec, the phase does not reach the limit (the phase delay is small), so that the vehicle can be quickly turned following the driver's steering operation, and the vehicle is steered by the steering operation. can do.

Further, the gain of the turning angular velocity 車 両 of the vehicle in the tire linear range (λ = 1) indicated by the characteristic line 48 in FIG. 10 shows almost the same characteristics as the characteristic line 40 in FIG. FIG.
The vehicle phase in the tire linear region (λ = 1) indicated by the characteristic line 52 in FIG. 1 shows almost the same characteristics as the characteristic line 44 in FIG. This is because the cornering power C ₁ of the front wheel and the cornering power C _{2 of the} rear wheel have extremely large values (C ₁ , C ₂ ≫α ₁ , α ₂ ) with respect to the respective proportional constants α ₁ , α ₂ . As can be seen from Equations 12 to 15, the transfer function H _V of the vehicle does not depend on the proportional constants α ₁ and α _2, and the transfer function of the conventional vehicle and the transfer function of the vehicle of the present embodiment are substantially the same. . That is, in the tire linear region where the frictional force between the front wheels 35 and the rear wheels 36 and the road surface is large, the turning moment of the vehicle by the differential device 7 hardly changes, and the vehicle according to the present embodiment is similar to the conventional vehicle. Steering can be performed by operating the steering wheel.

Thus, according to the present embodiment, since the turning moment is controlled based on the respective detection signals output from the turning angular velocity sensor 27 and the steering angle sensor 28, the turning angular velocity Ψ is attenuated. A large turning moment according to the steering angle δ can be applied, and the steering performance of the vehicle in accordance with the steering operation can be always secured, and the traveling performance of the vehicle can be improved.

That is, understeer occurs when the vehicle makes a left turn, and as shown in FIG. 12, when the actual traveling direction deviates to the right with respect to the operation direction in which the vehicle should turn as shown in FIG. Since the value decreases (lower), the first proportional operation circuit 32 outputs the first operation value S ₁ corresponding to the turning angular velocity 、, and the second proportional operation circuit 33 outputs the first operation value S 1. _A second calculated value S ₂ (S ₂ > S ₁ ) corresponding to the steering angle δ that is a value larger than ₁ is output. Then, the turning moment amount calculating circuit 34 outputs a turning moment amount M (M> 0) of a positive value from the first operation value S ₁ and the second operation value S ₂ .

Thus, the output signal setting circuit 31 determines that the vehicle is in an understeer state during a left turn, reduces the driving force applied to the left wheel shaft 9, and reduces the driving force applied to the right wheel shaft 10. Outputs a control signal for increasing. Then, the operating device 7 decelerates the left rear wheel 4 and increases the right rear wheel 5 in response to the control signal, and generates a turning moment in the left turning direction in the vehicle turning left,
The operation direction and the actual traveling direction of the vehicle can be made coincident with each other to avoid understeer during a left turn.

When the vehicle makes a left turn, oversteer occurs, and as shown in FIG. 13, when the actual traveling direction is deviated to the left with respect to the operation direction to which the vehicle should turn, as shown in FIG. Since the value increases (is high), the first proportional operation circuit 32 outputs a _first operation value S ₁ corresponding to the turning angular velocity 、, and the second proportional operation circuit 33 outputs the first operation value S _A second calculated value S ₂ (S ₂ <S ₁ ) corresponding to a steering angle δ smaller than ₁ is output. Then, the turning moment amount calculation circuit 34 outputs a turning moment amount M (M <0) of a negative value from the first operation value S ₁ and the second operation value S ₂ .

Thus, the output signal setting circuit 31 determines that the vehicle is in an oversteer state during a left turn, increases the driving force applied to the left wheel shaft 9, and increases the driving force applied to the right wheel shaft 10. Outputs a control signal for reduction. The operating device 7 increases the speed of the left rear wheel 4 and decelerates the right rear wheel 5 in response to the control signal, and generates a turning moment in the right turning direction for the vehicle turning left,
The operation direction and the actual traveling direction of the vehicle can be made coincident with each other to avoid oversteering when turning left.

Further, when the vehicle makes a left turn, a relatively large skid occurs. As shown in FIG. 14, when the vehicle skids to the right with respect to the operation direction, the turning angular velocity Ψ
Is larger than the steering angle δ. Therefore, the first proportional operation circuit 32 calculates the first operation value S corresponding to the turning angular velocity Ψ.
₁ and the second proportional operation circuit 33 outputs a _second operation value S ₂ (S ₂ > S ₁ ) corresponding to the steering angle δ that is larger than the first operation value S _1. . Then, the turning moment amount calculating circuit 34 outputs a turning moment amount M (M> 0) of a positive value from the first operation value S ₁ and the second operation value S ₂ .

Thus, the output signal setting circuit 31 determines that the vehicle is in the same state as the understeer state during the left turn, reduces the driving force applied to the left wheel axle 9, and applies the driving force to the right wheel axle 10. And outputs a control signal for increasing the driving force. Then, the operating device 7 decelerates the left rear wheel 4 and increases the right rear wheel 5 according to the control signal,
A turning moment in the left turning direction can be generated in the vehicle that is skidding, and the actual traveling direction of the vehicle can be corrected toward the operation direction determined by operating the steering wheel. Therefore, for example, when the driver returns the accelerator and the frictional force with the road surface increases due to a decrease in the rotation speed of the front wheels 2, 3 and the rear wheels 4, 5, the vehicle is quickly recovered in the operation direction. be able to.

On the other hand, when the vehicle turns to the right, understeer occurs, and as shown in FIG. 15, when the actual traveling direction deviates to the left with respect to the operation direction to which the vehicle should turn as shown in FIG. Is decreased (lower), the first proportional operation circuit 32 outputs the first operation value S ₁ corresponding to the turning angular velocity Ψ, and the second proportional operation circuit 33 outputs the first operation value outputting a second calculation value S ₂ corresponding to the steering angle becomes smaller than _{S 1 δ (S 2 <S} 1). Then, the turning moment amount calculation circuit 34 outputs a turning moment amount M (M <0) of a negative value from the first operation value S ₁ and the second operation value S ₂ .

Thus, the output signal setting circuit 31 determines that the vehicle is in an understeer state during a right turn, increases the driving force applied to the left wheel shaft 9, and increases the driving force applied to the right wheel shaft 10. And outputs a control signal for reducing. The operating device 7 increases the speed of the left rear wheel 4 and decelerates the right rear wheel 5 in response to the control signal, and generates a turning moment in the right turning direction in the vehicle turning right. ,
The operation direction and the actual traveling direction of the vehicle can be made coincident with each other to avoid understeer during a right turn.

When the vehicle makes a right turn, oversteer occurs, and as shown in FIG. 16, when the actual traveling direction deviates to the right with respect to the operation direction to which the vehicle should turn as shown in FIG. Is increased (high), the first proportional operation circuit 32 outputs a _first operation value S ₁ corresponding to the turning angular velocity Ψ, and the second proportional operation circuit 33 outputs the first operation value second calculation value corresponding to the steering angle becomes greater than _{S 1 δ S 2 (S 2} > S 1) and outputs a. Then, the turning moment amount calculating circuit 34 outputs a turning moment amount M (M> 0) of a positive value from the first operation value S ₁ and the second operation value S ₂ .

Thus, the output signal setting circuit 31 determines that the vehicle is in an oversteer state during a right turn, reduces the driving force applied to the left wheel shaft 9, and reduces the driving force applied to the right wheel shaft 10. And outputs a control signal for increasing. Then, the operating device 7 decelerates the left rear wheel 4 and increases the right rear wheel 5 in response to the control signal, and generates a turning moment in the left turning direction in the vehicle turning right,
The operation direction and the actual traveling direction of the vehicle can be made coincident with each other to avoid oversteer during a right turn.

Further, when the vehicle makes a right turn, the skid occurs, and as shown in FIG. 17, when the vehicle makes a relatively large left skid with respect to the operation direction, the value of the turning angular velocity が becomes the steering angle. is larger than δ, the first proportional operation circuit 32 outputs the first operation value S ₁ corresponding to the turning angular velocity Ψ, and the second proportional operation circuit 33 outputs the first operation value S ₁
The second calculated value S corresponding to the steering angle δ that is smaller than
₂ (S ₂ <S ₁ ) is output. Then, the turning moment amount calculating circuit 34 calculates the first calculated value S ₁ and the second calculated value S
A turning moment M of a negative value from ₂ (M <0) is output.

Thus, the output signal setting circuit 31 determines that the vehicle is in a state similar to the understeer state during a right turn, increases the driving force applied to the left wheel shaft 9, and applies the driving force to the right wheel shaft 10. A control signal for reducing the applied driving force is output. Then, the operating device 7 increases the speed of the left rear wheel 4 and decelerates the right rear wheel 5 according to the control signal,
A turning moment in the right turning direction can be generated in the vehicle that is skidding, and the actual traveling direction of the vehicle can be corrected toward the operation direction determined by operating the steering wheel. Therefore, for example, when the driver returns the accelerator and the frictional force with the road surface increases due to a decrease in the rotation speed of the front wheels 2, 3 and the rear wheels 4, 5, the vehicle is quickly recovered in the operation direction. be able to.

[0134] Furthermore, alpha proportional constant alpha ₁ of ₂ ≧ 5 × to satisfy the alpha ₁ relationship first proportional calculation circuit 32, because I proportionality constant alpha ₂ of second proportional calculation circuit 33 set in advance, the tire The gain of the turning angular velocity に 対 す る with respect to the steering angle δ at the limit can be kept at half or more of the tire linear range, and the vehicle can be steered even at the time of the tire limit at which the vehicle skids. The turning moment amount calculating circuit 34 calculates S ₁ = α
_{On the} basis of the first calculated value S _{1 of 1} × Ψ and the second calculated value S _{2 of} S ₂ = α ₂ × δ, the turning moment M
Is calculated as M = S ₂ −S ₁ , the output signal setting circuit 31 determines whether the value of the turning moment M is positive or negative, that is, α ₁ ×
Ψ, by determining the magnitude of α ₂ × δ, the understeer state and the oversteer state can be reliably determined.

Further, the proportional constant α ₁ of the first proportional operation circuit 32 is set in advance so as to satisfy the relation α ₁ ≧ (2/3) × I with respect to the moment of inertia I about the vertical axis of the center of gravity of the vehicle. Therefore, the response delay of the vehicle can be suppressed to 1.5 seconds or less, and the vehicle can be quickly steered by the driver's steering operation even at the time of the tire limit.

Further, since the electric motor 18 is incorporated in the operating device 7, the distribution of the driving force to the left and right wheel shafts 9 and 10 is achieved while reducing the size, weight and cost of the entire device. The ratio can be actively controlled.

In this embodiment, the case where the vehicle motion control device is applied to a rear wheel drive vehicle has been described as an example. However, the present invention is not limited to this, and is applicable to a front wheel drive vehicle and a four wheel drive vehicle. May be.

In this embodiment, the case where the electric motor 18 is used as the rotation source has been described as an example. However, a hydraulic motor is used as the rotation source, and the hydraulic motor is used to connect the left wheel axle to the differential case. It is good also as a structure which gives a relative rotational force to. In this case, the driving force applying means includes a hydraulic motor provided in the differential case for rotating the left wheel shaft, and a hydraulic pump for supplying pressure oil to the hydraulic motor via a hydraulic pipe provided in the differential housing. It is provided with a switching valve provided in a hydraulic pipe for switching the direction of pressure oil supplied to a hydraulic motor, and a pressure adjusting valve provided in a hydraulic pipe between the switching valve and the hydraulic pump for adjusting the pressure of the pressure oil. .

The switching valve is controlled by the driving force distribution means to switch the rotation direction of the hydraulic motor, and the pressure regulating valve is controlled by the driving force distribution means to control the rotation torque of the hydraulic motor. I can do it. Thereby, the driving force distribution means controls the distribution ratio of the driving force to the left and right wheel shafts, and the driving force applying means increases the speed of one wheel and decelerates the other wheel to the vehicle. A turning moment can be generated.

Further, in this embodiment, the steering angle δ is detected and
Although the configuration is such that the amount of turning moment M is calculated based on the detection signal of the steering angle δ, the configuration may be such that the amount of turning moment is calculated based on the detection signal of the rotation angle θ of the steering wheel. The proportionality constant α _{2 of} 33 is α ₂ ≧ (10/3) × (I /
N) may be set in advance.

[0141]

As described in detail above, according to the first aspect of the present invention, the driving force distribution means includes: a turning angular velocity detecting means for detecting a turning angular velocity Ψ; a steering angle detecting means for detecting a steering angle δ;
A turning moment amount calculating means for calculating a turning moment amount M based on respective detection signals output from the turning angular velocity detecting means and the steering angle detecting means; and a driving force applying means based on a calculation result of the turning moment amount calculating means. And output signal setting means for setting a control signal to be output, so that a turning moment M according to the steering angle δ is applied to the vehicle while decreasing the turning angular velocity Ψ, and the steering performance of the vehicle according to the steering operation is controlled. Can be secured at all times, and understeer and oversteer that occur when the vehicle turns can be avoided, and the traveling performance of the vehicle can be improved.

According to the second aspect of the present invention, the turning moment amount calculating means includes a first proportional calculating means for calculating a _first calculated value S ₁ corresponding to the turning angular velocity Ψ, and a steering angle δ. The second momentum M is calculated as M = S ₂ −S ₁ from a second proportional operation means for calculating a _second operation value S ₂ to be calculated, and the first operation value S ₁ and the second operation value S _2. The turning moment calculating means increases the turning moment M in proportion to the steering angle δ, decreases the turning moment M in proportion to the turning angular velocity 角, and sets the output signal. The turning moment M is generated in the vehicle by the means and the driving force applying means, so that the turning angular velocity Ψ of the vehicle is attenuated and the vehicle can be turned in proportion to the steering angle δ.

According to the third aspect of the invention, the output signal setting means reduces the driving force applied to the left wheel when the turning moment M is M> 0, and applies the output signal to the right wheel. Output a control signal to increase the driving force,
When the turning moment M is M <0, the control signal for increasing the driving force applied to the left wheel and decreasing the driving force applied to the right wheel is output.
An understeer state, an oversteer state, and the like can be reliably determined, and a turning moment in the left turning direction and the right turning direction can be generated in the vehicle, so that excessive understeer and oversteer can be avoided.

According to the invention of claim 4, α ₂ ≧ 5
Proportionality constant alpha ₁ of the first proportional calculation means to satisfy × alpha ₁ relationship, because I proportionality constant alpha ₂ of second proportional calculation means preset, the turning angular velocity Ψ for the steering angle δ when the tire limit Gain can be kept more than half of the tire linear range,
The vehicle can be steered even at the time of a tire limit at which the vehicle skids. Further, the turning moment amount calculating means calculates the first calculated values S ₁ and S ₂ = S ₁ = α ₁ × Ψ
Since the turning moment M is calculated as M = S ₂ −S ₁ based on the _second operation value S _{2 of} α ₂ × δ, the output signal setting means determines whether the value of the turning moment M is positive or negative, that is, By determining the magnitude of α ₁ × Ψ and α ₂ × δ, the understeer state and the oversteer state can be reliably determined.

Further, according to the fifth aspect of the present invention, the proportional constant α ₁ of the first proportional operation means is set so that α ₁ ≧ (2/3) × I Since the relationship is satisfied and the proportional constant α ₂ of the second proportional calculation means is set in advance so as to satisfy the relationship α ₂ ≧ (10/3) × I, the response delay of the vehicle is suppressed to 1.5 seconds or less. The vehicle can be quickly steered by the driver's steering wheel operation even at the time of tire limit.

Further, according to the invention of claim 6, the driving force applying means is constituted by an operating device for transmitting the rotating force of the differential case to the left and right wheel shafts, and a rotation source incorporated in the operating device. Accordingly, the ratio of the distribution of the driving force to the left and right wheel shafts can be positively controlled while reducing the size, weight, and cost of the entire apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a vehicle to which a turning moment control device according to an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view showing the actuator in FIG.

FIG. 3 is a block diagram illustrating a configuration of a control unit according to the present embodiment.

FIG. 4 is an explanatory diagram showing a relationship among a steering angle, a turning angular velocity, and a turning moment of the vehicle.

FIG. 5 is an explanatory diagram showing a relationship between a vehicle and a deviation dimension of a road when entering a curve.

FIG. 6 is a control block diagram of a vehicle explaining a movement including a driver.

FIG. 7 is an explanatory diagram showing a relationship between a driver's preview time and a response delay of a vehicle.

FIG. 8 is a characteristic diagram showing a relationship between a steering wheel operating frequency and a vehicle gain in the related art.

FIG. 9 is a characteristic diagram showing a relationship between a frequency of a steering wheel operation and a phase of a vehicle in the related art.

FIG. 10 is a characteristic diagram showing a relationship between a steering wheel operating frequency and a vehicle gain in the embodiment.

FIG. 11 is a characteristic diagram showing a relationship between a steering wheel operating frequency and a vehicle phase in the present embodiment.

FIG. 12 is an explanatory diagram illustrating an operation of avoiding understeer during a left turn.

FIG. 13 is an explanatory diagram illustrating an operation of avoiding oversteer during a left turn.

FIG. 14 is an explanatory diagram showing an operation of the vehicle in a skid state when turning left.

FIG. 15 is an explanatory diagram illustrating an operation of avoiding understeer during a right turn.

FIG. 16 is an explanatory diagram showing an operation of avoiding oversteer during a right turn.

FIG. 17 is an explanatory diagram showing an operation of the vehicle in a skidding state during a right turn.

[Explanation of symbols]

Reference Signs List 1 vehicle body 2, 3 front wheel 4, 5 rear wheel 7 differential device 18 electric motor (rotation source) 24 power storage device 25 motor control unit 27 turning angular speed sensor (turning angular speed detecting means) 28 steering angle sensor (steering angle detecting means) 29 Control unit 30 Turning moment amount calculation circuit (Turning moment amount calculation means) 31 Output signal setting circuit (Output signal setting means) 32 First proportional calculation circuit (First proportional calculation means) 33 Second proportional calculation circuit (No. 2 Proportional calculation means) 34 Turning moment amount calculation circuit (Turning moment amount calculation means)

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B62D 117: 00

Claims (6)

[Claims] 1. A driving force applying means provided on a vehicle body for applying different driving forces to left and right wheels, and applying the driving force to the left and right wheels in response to a control signal to operate the driving force applying means. A driving force distributing means for distributing a driving force to be applied, the driving force distributing means comprising: a turning angular velocity detecting means for detecting a turning angular velocity 回 り about a vertical axis of a center of gravity of the vehicle; The steering angle detection means for detecting the angle δ, the turning angle velocity Ψ output from the turning angular velocity detection means and the steering angle δ detection signal output from the steering angle detection means should be applied to the vehicle in proportion to the detection signal. A turning moment calculating means for calculating a turning moment M, and an output signal setting means for setting a control signal to be output to the driving force applying means based on the turning moment M calculated by the turning moment calculating means. A vehicle motion control device, comprising: 2. The turning moment amount calculating means includes: first proportional calculating means for calculating a _first calculated value S ₁ corresponding to the turning angular velocity 基 づ き based on a detection signal output from the turning angular velocity detecting means; A second proportional operation means for calculating a _second operation value S ₂ corresponding to the steering angle δ based on a detection signal output from the angle detection means;
Calculated value S ₂ of the first operational values S ₁ according to the first proportional calculation means subtracts from, the turning moment amount M M = S ₂ -
Vehicle motion control apparatus according to claim 1 comprising consist of the turning moment amount calculating means for calculating as S _1. 3. The output signal setting means sets the steering angle δ in the left turning direction to δ> 0, sets the steering angle δ in the right turning direction to δ <0, sets the turning angular velocity in the left turning direction to Ψ> 0, When the turning angular velocity 右 in the right turning direction is Ψ <0, the turning moment amount M is M
When> 0, the driving force applied to the left wheel is reduced,
A control signal for increasing the driving force applied to the right wheel is output. When the turning moment M is M <0, the driving force applied to the left wheel is increased, and the driving force applied to the right wheel is increased. The vehicle motion control device according to claim 1 or 2, wherein a control signal for reducing the vehicle speed is output. 4. The first proportional operation means calculates the first operation value S ₁ as S ₁ = α ₁ × Ψ (where α ₁ > 0). vehicle motion control apparatus according to the second calculation value S ₂ to S ₂ = α ₂ × δ (where, α ₂ ≧ 5 × proportionality constant consists of alpha ₁₎ according to claim 2 or 3 comprising a configuration that calculates as the. 5. When a moment of inertia about a vertical axis of the center of gravity of the vehicle is represented by I, a proportional constant α ₁
Is set in advance to α ₁ ≧ (2/3) × I, and the proportional constant α ₂ of the second proportional operation means is set in advance to α ₂ ≧ (10/3) × I. A vehicle motion control device according to claim 1. 6. An actuating device for transmitting a rotational force of a differential case rotated by a propulsion shaft to left and right wheel axles, and said driving force applying means is incorporated in said operating device and said left and right wheel axles. 6. The vehicle motion control device according to claim 1, further comprising a rotation source that applies a relative rotational force between one side of the vehicle and the differential case.