JPH09309357A - Yaw moment control method for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve an over-steering tendency so as to stabilize the behavior of a vehicle by determining the distribution quantity of driving force or braking force by feedforward control, and decreasing the distribution quantity by feedback control at the time of detecting the over-steering state of the vehicle. SOLUTION: An electronic control unit U inputting signals of a vehicle speed sensor 10a, a steering angle sensor 10b, a lateral acceleration sensor 10c and a yaw rate sensor 10d is provided with a feedforward control part and a feedback control part, and during driving of a vehicle, a normal yaw rate is computed in the feedback control part. The deviation between an actual yaw rate and the normal yaw rate is then computed. This deviation is inputted to the feedforward control part so as to be converted into the driving force distribution quantity, and this distribution quantity is deducted from the driving force distribution quantity, computed in the feedforward control part, to make a correction. That is, when the driving force distribution quantity becomes excessive to generate an over-steering tendency to the vehicle, the driving force distribution quantity is corrected in a decrease direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yaw moment control method for a vehicle that distributes a driving force or a braking force to the left and right wheels of the vehicle to control the yaw moment.

[0002]

2. Description of the Related Art In a driving force distribution device for distributing a driving force to left and right wheels to control a yaw moment, a driving force distribution amount is fed based on an accelerator opening, an engine speed, a vehicle speed, a steering force and a lateral acceleration. The one that performs forward control is known from Japanese Patent Application Laid-Open No. 1-182127.

[0003]

By the way, the above-mentioned conventional one can perform highly responsive control by adopting the feedforward control, but since the feedback control is not performed, the accuracy is not necessarily high. It was not possible to perform high control.

The present invention has been made in view of the above-mentioned circumstances, and achieves both control response and accuracy in a yaw moment control by distributing a driving force or a braking force to the left and right wheels of a vehicle. With the goal.

[0005]

In order to achieve the above object, the invention described in claim 1 is a yaw of a vehicle for controlling a yaw moment by distributing a driving force or a braking force to the left and right wheels of the vehicle. In the moment control method, the distribution amount of the driving force or the braking force is determined by the feedforward control, and when the oversteer state of the vehicle is detected, the distribution amount is reduced by the feedback control.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 7 show an embodiment of the present invention. FIG. 1 is a skeleton diagram showing a power transmission system of a vehicle, and FIG.
1 is an enlarged view of part 2 of FIG. 1, FIG. 3 is an enlarged view of part 3 of FIG. 1, FIG. 4 is a first partial view of a hydraulic circuit, FIG. 5 is a second partial view of a hydraulic circuit, and FIG.
Is a block diagram of a control system, and FIG. 7 is a graph showing a method for setting a standard yaw rate.

As shown in FIG. 1, a transmission M is connected to the right end of an engine E mounted laterally on the front of the vehicle body, and a driving force distribution device T is arranged at the rear of the engine E and the transmission M. It A left front wheel W _FL and a right front wheel W _FR , which are drive wheels, are connected to the left drive shaft A _L and the right drive shaft A _R extending from the left end and the right end of the driving force distribution device T to the left and right.

The driving force distribution device T is a differential D in which driving force is transmitted from an external gear 3 that meshes with an input gear 2 provided on an input shaft 1 extending from a transmission M.
Is provided. The differential D is composed of a double pinion type planetary gear mechanism, and meshes with the ring gear 4 formed integrally with the external gear 3, a sun gear 5 coaxially arranged inside the ring gear 4, and the ring gear 4. An outer planetary gear 6 and an inner planetary gear 7 that meshes with the sun gear 5 are supported by a planetary carrier 8 that supports them in a mutually meshing state. The differential D has its ring gear 4
, Which functions as an input element, and the sun gear 5, which functions as one output element, is connected to the left drive shaft A _L via the half shaft 9, and the planetary carrier 8 which functions as the other output element has a right drive shaft A _R. Connected to.

A carrier member 11 rotatably supported on the outer circumference of the half shaft 9 is provided with four pinion shafts 12 ... Which are arranged at 90 ° intervals in the circumferential direction,
The three pinion members 16 ... In which the first pinion 13, the second pinion 14, and the third pinion 15 are integrally formed are rotatably supported by the respective pinion shafts 12. The number of the triple pinion members 16 ... Is four in the embodiment, but the number is not limited to four and may be two or more.

A first sun gear 1 which is rotatably supported on the outer periphery of the half shaft 9 and meshes with the first pinion 13.
7 is connected to the planetary carrier 8 of the differential D. The second sun gear 18 fixed to the outer circumference of the half shaft 9 meshes with the second pinion 14.
Further, the third sun gear 19 rotatably supported on the outer periphery of the half shaft 9 meshes with the third pinion 15.

The number of teeth of the first pinion 13, the second pinion 14, the third pinion 15, the first sun gear 17, the second sun gear 18, and the third sun gear 19 in the embodiment are as follows.

The number of teeth P of the first pinion 13 P₁= 16 Number of teeth of the second pinion 14 P_Two= 16 Number of teeth of the third pinion 15 P_Three= 32 Number of teeth of the first sun gear 17 S₁= 30 Number of teeth of the second sun gear 18 S_Two= 26 Number of teeth of the third sun gear 19 S_Three= 28 Therefore, the first pinion 13 and the first sun that mesh with each other
The gear ratio of the gear 17 is R ₁(= P₁/ S₁) And then mutually
Gears of the second pinion 14 and the second sun gear 15 that mesh with each other
Ratio to R_Two(= P_Two/ S_Two), And the third pin meshes with each other.
Set the gear ratio of the union 15 and the third sun gear 19 to R_Three(= P
_Three/ S_Three), Then R₁: R_Two: R_Three= 16/30: 16/26: 32/28 = 1.00: 1.15: 2.14.

A third sun gear 19 can be connected to the casing 20 via a left hydraulic clutch C _L, the rotational speed of the carrier member 11 is increased by the engagement of the left hydraulic clutch C _L. The carrier member 11 can be coupled to the casing 20 via a right hydraulic clutch C _R, the rotation speed of the carrier member 11 is reduced by the engagement of the right hydraulic clutch C _R.

The left hydraulic clutch C _L and the right hydraulic clutch C _R are composed of a vehicle speed sensor 10a and a steering angle sensor 1
0b, lateral acceleration sensor 10c, and yaw rate sensor 10
The electronic control unit U, to which the signal from d is input, is controlled via the hydraulic circuit H.

Next, the structure of the differential D will be further described with reference to FIG.

The differential D is housed inside the left casing 21 and the right casing 22 which form the casing of the transmission M. Left casing 21
The roller bearing 23 provided on the right casing 22 and the roller bearing 24 provided on the right casing 22,
The differential gear box 25 having the above is rotatably supported. Differential gearbox 25
The planetary carrier 8 is rotatably supported inside, and a first sleeve 26 splined to the center of the left side of the planetary carrier 8 extends through the differential gearbox 25 and the left casing 21 to the left side. At the same time, the right drive shaft A _R splined to the right center of the planetary carrier 8 is connected to the differential gear box 25 and the right casing 22.
Through and extend to the right.

The right shaft half 28 of the half shaft 9 divided into two is spline-coupled to the center of the sun gear 5 which is rotatably supported at the center of the planetary carrier 8 via a needle bearing 27. Plural planetary gear shafts 29 provided on the planetary carrier 8
In addition, the outer planetary gear 6 that meshes with the ring gear 4 provided in the differential gear box 25.
And the inner planetary gear 7 that meshes with the sun gear 5.
And are supported (only the outer planetary gear 6 is shown in FIG. 2).

Next, the structure of the driving force distribution device T will be further described with reference to FIG.

The casing 20 of the driving force distribution device T comprises a left casing 30, a central casing 31 and a right casing 32 which are axially divided into three parts. Right casing 32
A second sleeve 33, which is spline-coupled to the left end of the first sleeve 26, is supported via a ball bearing 34. Inside the second sleeve 33, a left shaft half 35 of the half shaft 9 is a needle. It is rotatably supported via bearings 36, 36. The half shaft 9 housed inside the first sleeve 26 and the second sleeve 33, which are spline-coupled, is integrally formed by coaxially fitting the left end inner circumference of the right shaft half body 28 to the right end outer circumference of the left shaft half body 35. Splined to. The left end of the left shaft half 35 of the half shaft 9 supported by the left casing 30 via a ball bearing 37 extends from the left casing 30 to the outside and extends to the left drive shaft A _L.
Are spline-connected.

The carrier member 11 is rotatably supported by a clutch housing 38 and a right casing 32, which are integrally formed inside the central casing 31, via a pair of ball bearings 39 and 40. The plurality of pinion shafts 12 provided on the carrier member 11 support the triple pinion members 16 including the first pinion 13, the second pinion 14, and the third pinion 15, respectively.
The first pinion 13 meshes with the first sun gear 17 that is splined to the outer circumference of the second sleeve 33, and the second pinion 14 meshes with the second sun gear 18 that is splined with the left shaft half 35 of the half shaft 9. The third pinion 15 is a third sleeve 4 rotatably supported on the outer periphery of the left shaft half 35 through a needle bearing 42.
3 meshes with the third sun gear 19 formed integrally.

The left hydraulic clutch C _L includes a plurality of friction engagement elements 44, which are arranged between the central casing 31 and the third sleeve 43, a piston 45 for hydraulically engaging the friction engagement elements 44, and a piston. And a return spring 46 for urging 45 in the non-engaging direction. Also, the right hydraulic clutch C
_R is a plurality of friction engagement elements 47 ... Arranged between the central casing 31 and the carrier member 11, and a friction engagement element 47.
A piston 48 that hydraulically engages each other and a return spring 49 that biases the piston 48 in the non-engaging direction are provided.

The hydraulic pump 51 provided on the left casing 30 and covered by the pump cover 50 is a trochoid pump having an outer rotor 52 and an inner rotor 53. Left casing 30 and pump housing 5
The pump shaft 56 supported by the ball bearings 54 and 55 at 0 is provided with a pump driven gear 57 at the shaft end portion protruding rightward from the pump cover 50, and the pump driven gear 57 of the half shaft 9 is provided. It is driven by meshing with a pump drive gear 58 that is splined to the left shaft half body 35.

A gear cover 59 made of a steel plate press is mounted on the right side surface of the pump cover 50 so as to cover the pump drive gear 58 and the pump driven gear 57. The lower part of the pump drive gear 58 is soaked in the oil accumulated at the bottom of the casing 20, and if oil splashes are scattered inside the casing 20 as the pump drive gear 58 rotates, the oil level of the oil may change greatly. Although the oil may leak from the breather passage, by mounting the gear cover 59, it is possible to reliably prevent the oil from scattering and solve the problem. Since the gear cover 59 is made of pressed steel plate, it is lightweight and inexpensive, and can be easily attached and detached so that the material and shape can be easily changed.

Left casing 30 and central casing 31
An oil reservoir 60 is formed in the lower portion of the oil reservoir 60, and the oil stored in the oil reservoir 60 is pumped up to the hydraulic pump 51 via a strainer 61. A valve block 62 for controlling engagement / disengagement of the left hydraulic clutch C _L and the right hydraulic clutch C _R with oil from the hydraulic pump 51 is provided on the upper surface of the central casing 31.

Next, the hydraulic circuit H will be described with reference to FIGS. 4 and 5.
The configuration of will be described.

The hydraulic pump 51 moves from the oil reservoir 60 to the oil passage L.
₁Oil pumped through the regulator valve 65
After the primary pressure adjustment in the
Road L _TwoIs supplied to the linear solenoid valve 67 via
Secondary pressure is adjusted. Extending from the linear solenoid valve 67
Oil path L_ThreeSplit into two in the middle and left shift
Renoid valve 68_LAnd right shift solenoid valve 6
8_RConnected to. And left shift solenoid valve 6
8_LIs the left oil pressure sensor 69_LOil passage L_FourThrough
Left hydraulic clutch C_LConnected to the right shift
Renoid valve 68_RIs the right oil pressure sensor 69_RThrough
Oil passage L_FiveVia right hydraulic clutch C_RConnected to. Ma
Oil passage L for lubrication extending from the regulator valve 65₆
Passes through the clutch housing 38 and the half shaft
It communicates with the outer circumference of 9.

The oil passages L _{1 to} L ₆ for transmitting the oil pressure from the hydraulic pump 51 and the oil passages connected to the oil passages L _{1 to} L ₆ are connected to the casing 20 of the driving force distribution device T and the valve block 62 directly connected to the casing 20. And formed.

In FIG. 4, reference numeral 70 is a cooler relief valve, reference numeral 71 is a lubrication / cooler relief valve, reference numeral 72 is a drain filter, and reference numeral 73 is a cold water cooler with a built-in radiator.

The linear solenoid valve 67, the left shift solenoid valve 68 _L and the right shift solenoid valve 68 _R are connected to and controlled by the electronic control unit U. The linear solenoid valve 67 further secondarily regulates the hydraulic pressure that has been primarily regulated by the regulator valve 65 to arbitrarily adjust the engagement force of the left hydraulic clutch C _L and the right hydraulic clutch C _R. Also left shift solenoid valve 68 _L
Open and close the the ON / OFF controlled by the oil passage L _4, to control the engagement / disengagement of the left hydraulic clutch C _L, right shift solenoid valve 68 _R is is ON / OFF control of the oil passage L ₅ It opens and closes to control engagement / disengagement of the right hydraulic clutch C _R.

As described above, since the hydraulic pump 51 is arranged inside the casing 20 of the driving force distribution device T, the oil passages L ₁ to L ₁ connecting the hydraulic pump 51 to the left and right hydraulic clutches C _L and C _R are connected. L ₅ and its associated oil passages may be formed in the casing 20 and the valve block 62 directly coupled to the casing 20. As a result, the length of the oil passage can be minimized, and the pipe extending to the outside of the casing 20 can be eliminated. If the hydraulic pump 51 is provided in the engine E or the transmission M, not only the length of the oil passage is increased, but also the pipe needs to be installed outside the casing, which is used in the driving force distribution device T. It is difficult to cope with the case where the type of oil and the type of oil used in the engine E or the transmission M are different. Further, since the oil pump 51 is driven by the half shaft 9 connected to one wheel (the front left wheel W _{FL in the} embodiment), the drive system for transmitting the driving force to the hydraulic pump 51 can be simplified.

Next, the operation of the embodiment of the present invention having the above construction will be described.

In FIG. 6, the electronic control unit U includes a feedforward control unit and a feedback control unit, and the feedforward control unit has a vehicle speed sensor 10 therein.
a, the steering angle sensor 10b, and the lateral acceleration sensor 10c, as well as the engine torque and the engine speed, are input, and the feedback control unit includes the vehicle speed sensor 10a,
The signals from the lateral acceleration sensor 10c and the yaw rate sensor 10d are input.

The feedforward controller determines the lateral acceleration based on the output of the lateral acceleration sensor 10c, and estimates the lateral acceleration based on the output of the vehicle speed sensor 10a and the output of the steering angle sensor 10b. The turning amount of the vehicle is calculated based on the lateral acceleration of the vehicle. The estimated lateral acceleration rises faster than the lateral acceleration determined based on the output of the lateral acceleration sensor 10c. On the other hand, the gear ratio is determined based on the output of the vehicle speed sensor 10a and the engine speed, and the driving force of the vehicle is calculated based on this gear ratio and the engine torque.

In order to obtain the driving force distribution amount ΔT, the driving force distribution device determines the driving force distribution amount ΔT to be distributed to the left and right front wheels W _FL and W _FR based on the product of the driving force and the turning amount. The linear solenoid 6 so that the hydraulic pressure required for the left hydraulic clutch _CL or the right hydraulic clutch _CR is output.
The amount of electricity supplied to 7 is controlled. Further, the turning direction is judged based on the turning amount, the left shift solenoid valve 68 _L is energized to engage the left hydraulic clutch C _L when turning left, and the right hydraulic clutch C _R is engaged when turning right. Therefore, the right shift solenoid valve 68 _R is energized.

The feedback control unit is used for the vehicle speed sensor 10
Based on the output of a and the output of the lateral acceleration sensor 10c,
A standard yaw rate is calculated from the vehicle model shown in FIG. Then, a deviation β between the actual yaw rate detected by the yaw rate sensor 10d and the reference yaw rate is calculated, the deviation β is input to the feedforward control unit to be converted into the driving force distribution amount ΔT, and the driving force distribution amount ΔT is calculated. Correction is performed by subtracting from the driving force distribution amount ΔT calculated by the feedforward control unit. Specifically, when the driving force distribution amount ΔT becomes excessive and an oversteer tendency occurs in the vehicle, the driving force distribution amount ΔT is corrected in a decreasing direction to eliminate the oversteering tendency. Thus, the driving force distribution amount ΔT distributed to the left and right front wheels W _FL and W _FR by the driving force distribution device T is controlled by both feedforward control and feedback control.

As described above, by the feedforward control, the driving force distribution amount required to generate an appropriate yaw moment in the vehicle is estimated based on the vehicle speed, the steering angle lateral acceleration, etc., and the driving force distribution amount is obtained. Since the left and right hydraulic clutches C _L and C _R are controlled as described above, highly responsive control can be performed. If oversteer tendency occurs in the vehicle by feedback control that converges the deviation between the actual yaw rate and the standard yaw rate to zero with high accuracy, the oversteer tendency can be eliminated and the behavior of the vehicle can be stabilized. .

Next, the operation of the driving force distribution device T will be described.

When the vehicle is traveling straight, the left hydraulic clutch C_L
And right hydraulic clutch C_RAre disengaged. This
As a result, the carrier member 11 and the third sun gear 19 are restrained.
Bundle is released, half shaft 9, left drive shaft
A_L, Right drive shaft A _R, Differential D
All planetary carriers 8 and carrier members 11 are
It becomes a body and rotates. At this time, the torque of the engine E is
Left and right front wheels W from differential D_FL, W_FREqual to
Be transmitted to.

When the vehicle turns right, the right hydraulic clutch C _R is engaged via the electronic control unit U and the hydraulic circuit H to connect the carrier member 11 to the casing 20 and stop it. At this time, the half shaft 9 and the left drive shaft A _L integrated with the left front wheel W _FL and the right drive shaft A _R integrated with the right front wheel W _FR (that is, the planetary carrier 8 of the differential D) are the second sun gear 18 ,
Since the second pinion 14, the first pinion 13 and the first sun gear 17 are connected, the rotational speed N _L of the left front wheel W _FL is expressed by the following equation with respect to the rotational speed N _R of the right front wheel W _FR. Be accelerated.

[0041]

[Equation 1]

As described above, the rotation speed N of the left front wheel W _FL
L can be transmitted when it is increased relative to the rotational rate N _R of the right front wheel W _FR, a part of the torque of an inner wheel right front wheel W _FR to the left front wheel W _FL is the outer turning wheel.

The carrier member 11 is connected to the right hydraulic clutch C.
Instead of stopping by _R, if reducing the rotational speed of the carrier member 11 by appropriately adjusting the engagement force of the right hydraulic clutch C _R, the right front wheel W _FR and rotation speed N _L of the left front wheel W _FL in accordance with the deceleration It is possible to increase the speed with respect to the rotation speed N _{R of the above} , and to transmit an arbitrary torque from the right front wheel W _FR which is the turning inner wheel to the left front wheel W _FL which is the turning outer wheel.

On the other hand, when the vehicle turns left, the electronic control unit
The left hydraulic clutch C via the valve U and the hydraulic circuit H._LBut
The third pinion 15 through the third sun gear 19.
Connected to the housing 20. As a result, half shaft
The rotation speed of the carrier member 11 is increased with respect to the rotation speed of 9.
Right front wheel W_FRNumber of revolutions N_RLeft front wheel W_FLNumber of revolutions N _L
The speed is increased according to the following equation.

[0045]

[Equation 2]

As described above, the rotation speed N of the right front wheel W _FR
When _R is increasing relative to the rotational rate N _L of the left front wheel W _FL, it is possible to transmit the part of the torque of a turning inner front left wheel W _FL to a turning outer front right wheel W _FR. Also in this case,
If the rotational speed of the carrier member 11 is increased by appropriately adjusting the engaging force of the left hydraulic clutch C _L , the rotational speed N _R of the right front wheel W _FR is changed to the rotational speed N _{L of the} left front wheel W _FL according to the increased speed. As a result, it is possible to increase the speed and to transmit an arbitrary torque from the left front wheel W _FL which is the turning inner wheel to the right front wheel W _FR which is the turning outer wheel.

As is clear by comparing the equations (1) and (2), the first pinion 13, the second pinion 14, and the third pinion 13
By setting the number of teeth of the pinion 15, the first sun gear 17, the second sun gear 18, and the third sun gear 19 as described above, the speed increasing ratio from the right front wheel W _FR to the left front wheel W _FL (about 1.1
538) and the speed increasing ratio (about 1.1555) from the left front wheel W _FL to the right front wheel W _FR are made substantially equal, and the difference is only 0.15.
It can be kept within%. Accordingly, the driving force transmission capacity of the left hydraulic clutch C _L and the right hydraulic clutch C _R, or left hydraulic clutch C _L and without specially providing a difference in hydraulic pressure supplied to the right hydraulic clutch C _R, the left front wheel W _FL and The driving force can be distributed symmetrically between the right front wheels W _FR , and the left hydraulic clutch C _L and the right hydraulic clutch C _R can be used in common and the control system can be simplified to reduce costs. Become.

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention.

For example, in the embodiment, the standard yaw rate is calculated using the vehicle speed and the lateral acceleration as parameters, but it is also possible to calculate the standard yaw rate from the vehicle model shown in FIG. 7B using the vehicle speed and the steering angle as parameters. is there.
Further, although the embodiment relates to the driving force distribution device, the present invention can be applied to a braking force distribution device that distributes the braking force to the left and right wheels to generate a yaw moment.

[0050]

As described above, according to the invention described in claim 1, since the distribution amount of the driving force or the braking force is determined by the feedforward control, the yaw moment of the vehicle is highly responsive and without delay. When the oversteer state of the vehicle that can be controlled is detected, the distribution amount is reduced by highly accurate feedback control, so that the oversteer tendency can be effectively eliminated and the behavior of the vehicle can be stabilized. it can.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing a power transmission system of a vehicle.

FIG. 2 is an enlarged view of part 2 of FIG.

FIG. 3 is an enlarged view of a part of FIG. 1;

FIG. 4 is a first diagram of a hydraulic circuit.

FIG. 5 is a second diagram of the hydraulic circuit;

FIG. 6 is a block diagram of a control system.

FIG. 7 is a graph showing a standard yaw rate setting method.

[Explanation of symbols]

H Hydraulic circuit U Electronic control unit W _FL Left front wheel (wheel) W _FR Right front wheel (wheel)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kenji Honda 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Honda R & D Co., Ltd.

Claims (1)

[Claims] 1. A yaw moment control method for a vehicle, wherein a yaw moment is controlled by distributing a driving force or a braking force to left and right wheels of the vehicle, wherein the distribution amount of the driving force or the braking force is determined by feedforward control. A yaw moment control method for a vehicle, wherein the distribution amount is reduced by feedback control when an oversteer state of the vehicle is detected.