KR20130057841A - Torque vectoring systen for vehicle and control method for vehicle - Google Patents

Abstract

PURPOSE: A torque vectoring system of a vehicle and a control method thereof are provided to apply changes in a car height, which are generated by the turning movement of the car, to a torque vectoring control, thereby controlling the movement of the car accurately and stably. CONSTITUTION: A torque vectoring system of a car comprises a turning information detecting unit, a control unit, and a torque vectoring unit. The control unit decides the final torque according to the amount of distribution torque and of driving limit torque, and controls a vehicle by distributing driving power of torque vectoring. The torque vectoring unit distributes and controls the torque which is applied to each wheel according to the control of the control unit. [Reference numerals] (AA) Start; (BB,DD,FF,HH) No; (CC,EE,GG,II) Yes; (JJ) End; (S101) Detect steering angle, wheel speed, lateral acceleration, and yaw rate; (S102) Calculate target yaw rate; (S103) Compare real yaw rate and target yaw rate; (S104) Is it over a reference value?; (S105) Is understeer generated?; (S106) Turning inner wheel torque calculation; (S107) Turning outer wheel torque calculation; (S108) Compare a speed difference between a front wheel and a back wheel; (S109) Speed difference>reference value?; (S110) Slip torque calculation; (S111) Determine distribution torque in each wheel; (S112) Garage change measurement; (S113) Vertical reaction calculation; (S114) Determine driving limit torque; (S115) Distribution torque in each wheel and driving limit torque comparison; (S116) Distribution torque<driving restriction torque; (S117) Distribution torque application in each wheel; (S118) Driving limit torque application; (S119) Torque vectoring control

Description

TORQUE VECTORING SYSTEN FOR VEHICLE AND CONTROL METHOD FOR VEHICLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque vectoring system of a vehicle, and more particularly, to a turning control apparatus and method of a vehicle in which a vertical drag on a change in a garage generated by turning of a vehicle is applied to provide a torque vectoring control.

Torque Vectoring System is applied to four-wheel drive (4WD) vehicles based on the front engine rear drive, and it detects the information of the turning request when the vehicle turns and calculates the required torque in each wheel. Next, by actively distributing and controlling the driving torque of each wheel, it is a system that improves the starting performance of the vehicle and provides the stability of running and adjusting during turning.

When the vehicle is running, the load on the wheels changes in real time according to acceleration or geometry, and even if the target driving force is given to each wheel, it cannot be 100% exhibited.

Since the driving force F = W × ax, Wt = F / μ of the wheel is satisfied, it can be said that the limit of the driving force of the wheel changes as the height of the garage W, ie, the vertical drag, changes as shown in the equation.

In addition, since the load applied to each wheel is rapidly changed by the weight transformer in a state in which the vehicle is turning at a high speed or rapidly starting, the torque vectoring control for allocating driving force to increase steering stability can be greatly affected.

It is an object of the present invention to provide a more accurate and stable torque vectoring control by applying vertical drag to a change in height generated as the vehicle turns.

Features according to an embodiment of the present invention includes a turning information detector for detecting turning information of the vehicle; The distribution torque for each wheel is determined from the turning information, and the driving limit torque is determined by calculating the vertical force from the height change, and the final torque is determined according to the distribution torque and the magnitude of the driving limit torque, thereby allocating the driving force of torque vectoring. A control unit; According to the control of the controller, a torque vectoring system of a vehicle including a torque vectoring mechanism is provided to distribute torque applied to each wheel.

The turning information detection unit includes a steering angle detection unit that detects a steering angle and a steering direction; A wheel speed detection unit detecting a speed for each wheel; A lateral acceleration detector for detecting lateral acceleration of the vehicle; Yaw rate detection unit for detecting the yaw moment of the vehicle; It may include a garage detection unit mounted to the axle of the vehicle for detecting a change in the height of each axle generated in the turning process.

The control unit calculates a target yaw rate using the steering angle, the speed of each wheel, and the lateral acceleration, and if the difference between the detected actual yaw rate and the calculated target yaw rate is less than or equal to the set reference value, the controller compares the speeds of the front wheel and the rear wheel to the slip state. And the slip torque is calculated according to the slip degree of each wheel to determine the distribution torque for each wheel.

The controller may determine the distribution torque for each wheel by calculating the torque of the turning inner ring when the difference between the detected actual yaw rate and the calculated target yaw rate is equal to or greater than a set reference value and understeer occurs.

The controller may determine the distribution torque for each wheel by calculating the torque of the turning outer ring when the difference between the detected actual yaw rate and the calculated target yaw rate is equal to or greater than a set reference value and oversteer occurs.

The control unit may calculate the vertical drag from the change in the height of the inner and outer shafts according to the turning provided by the garage detection unit, and calculate the driving limit torque using the vertical drag.

The controller compares the distribution torque for each wheel with the driving limit torque calculated by the vertical force, and when the distribution torque for each wheel is greater than the driving limit torque, the torque vectoring can be controlled by applying the torque allocated to each wheel as the driving limit torque. .

The controller may control torque vectoring by applying torque distributed to each wheel as it is if the distribution torque for each wheel is smaller than the driving limit torque by comparing the distribution torque for each wheel and the driving limit torque calculated for the vertical drag.

According to another embodiment of the present invention, there is provided a method for determining slip torque of a wheel and distribution torque for each wheel by detecting turning information of a vehicle; Determining the driving limit torque by calculating the vertical force in the garage change; When the distribution torque is greater than the drive limit torque by comparing the distribution torque and the magnitude of the drive limit torque, torque vectoring is controlled by applying the drive limit torque. When the distribution torque is less than the drive limit torque, torque vectoring is controlled by applying the distribution torque. Provided is a method of controlling a torque vectoring system for a vehicle comprising a process.

The slip torque of the wheel may be determined according to the speed difference when the speed difference between the front wheel and the rear wheel is more than the reference value, and the distribution torque for each wheel may be determined as the turning inner wheel torque and the turning outer wheel torque according to the occurrence of understeer or oversteer.

A feature according to another embodiment of the present invention is a process of calculating a target yaw rate using the steering angle, the speed of each wheel, and the lateral acceleration, and determining whether a difference between the detected actual yaw rate and the calculated target yaw rate is greater than or equal to a set reference value. ; If the difference between the actual yaw rate and the target yaw rate is less than or equal to the reference value, determining the slip state by comparing the speeds of the front and rear wheels, and calculating the slip torque according to the slip degree of each wheel to determine the distribution torque for each wheel; If the difference between the actual yaw rate and the target yaw rate is greater than or equal to the reference value and understeer is generated, determining the torque distribution for each wheel by calculating the torque of the turning inner ring; If the difference between the actual yaw rate and the calculated target yaw rate is greater than or equal to the set reference value, and oversteer occurs, determining the torque distribution for each wheel by calculating the torque of the turning outer ring; Calculating the normal drag at the height change of the inner and outer shafts according to the turning, and calculating the driving limit torque using the vertical drag; Controlling torque vectoring by applying torque allocated to each wheel as a driving limit torque when the distribution torque for each wheel is compared with the driving limit torque calculated by the vertical force, and the driving torque is greater than the driving limit torque; Torque vectoring of a vehicle including the process of controlling torque vectoring by applying the torque allocated to each wheel as it is if the distribution torque for each wheel is smaller than the driving limit torque by comparing the distribution torque for each wheel with the driving limit torque calculated from the vertical drag. A system control method is provided.

As described above, the present invention can more accurately and stably adjust the behavior of the vehicle by applying the height change generated by the turning of the vehicle to the torque vectoring control.

1 is a view schematically showing a torque vectoring system of a vehicle according to an embodiment of the present invention.
2 is a flowchart schematically illustrating a control procedure of a torque vectoring system of a vehicle according to an exemplary embodiment of the present invention.
3 is a view showing a load movement according to the turning of the vehicle.
4 is a diagram illustrating a relationship between a driving force and a cornering force according to the turning of the vehicle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

The present invention can be embodied in various different forms, and thus the present invention is not limited to the embodiments described herein.

1 is a view schematically showing a torque vectoring system of a vehicle according to an embodiment of the present invention.

Referring to FIG. 1, an embodiment of the present invention includes a turning information detection unit 100, a control unit 200, and a torque vectoring mechanism 300.

The turning information detection unit 100 detects a change in the height of the steering angle and the steering direction, the speed for each wheel, the lateral acceleration, the yaw rate, and the turning, and provides the information to the controller 200.

The turning information detection unit 100 includes a steering angle detection unit 101, a wheel speed detection unit 102, a lateral acceleration detection unit 103, a yaw rate detection unit 104, and a garage detection unit 105.

The steering angle detector 101 may be mounted on the steering column, and detect the steering angle and the steering direction of the steering wheel according to the driver's turning request, and provide information about the steering angle to the controller 200.

The steering angle detector 101 may be applied as a component of a motor driven power steering (MDPS) system.

The wheel speed detection unit 102 is installed at each wheel to detect the speed for each wheel and provide information to the controller 200.

The lateral acceleration detector 103 detects lateral acceleration generated according to the turning of the vehicle and provides information about the lateral acceleration to the controller 200.

The yaw rate detector 104 detects a yaw moment that is about to be rotated with respect to the vehicle center and provides information about the yaw moment to the controller 200.

The garage detection unit 105 is mounted on the axle of the vehicle and detects a change in the height of each axle generated during the turning of the vehicle and provides information about the height to the controller 200.

The garage detection unit 105 may be applied as a sensor used in an electric control suspension (ECS).

The controller 200 calculates a target yaw rate using the steering angle provided from the turning information detector 100, the speed of each wheel, and the lateral acceleration in the driving state, and calculates the actual yaw rate provided from the yaw rate detector 104. If the difference is less than the set reference value by comparing the target yaw rate, the slip state is determined by comparing the speeds of the front and rear wheels, and then the slip torque is calculated according to the slip degree of each wheel to determine the distribution torque for each wheel.

In addition, the controller 200 compares the actual yaw rate provided by the yaw rate detector 104 with the calculated target yaw rate, and if the difference is greater than or equal to a set reference value, whether the under steer is generated or over steer. If it is an understeer occurrence, the torque of the turning inner ring is calculated, and if the oversteer is generated, the torque of the turning outer ring is calculated to determine the distribution torque for each wheel.

In addition, the controller 200 calculates the vertical drag from the change of the height of the inner and outer shafts according to the turning provided by the garage detector 105, and calculates the driving limit torque using the vertical drag.

Subsequently, the controller 200 compares the driving limit torque calculated by using the distribution torque for each wheel and the vertical drag, and when the distribution torque for each wheel is larger than the driving limit torque, the limit calculated from the change of the garage by the torque allocated to each wheel. The torque is applied to provide a torque vectoring control value to the torque vectoring mechanism 300.

In addition, the control unit 200 compares the distribution torque for each wheel and the driving limit torque calculated by using the vertical drag, and when the distribution torque for each wheel is smaller than the driving limit torque, torque vectoring is applied as it is applied to each wheel as it is. It is provided to the instrument 300 as a torque vectoring control value.

The torque vectoring mechanism 300 is composed of a planetary gear and a multi-plate clutch operated by electronic or hydraulic pressure, and distributes the driving force of the front, rear, left, and right wheels by operating the planetary gear and the multi-plate clutch according to a control signal applied from the controller 200. Is applied.

The operation of the present invention including the function as described above can be executed as follows.

When the vehicle to which the present invention is applied operates, the turning information detecting unit 100 detects a change in the height of the steering angle, the steering direction, the speed for each wheel, the lateral acceleration, the yaw rate, and the turning to the controller 200 (S101). .

At this time, the control unit 200 calculates the target yaw rate by using the steering angle provided by the turning information detector 100, the speed of each wheel, and the lateral acceleration (S102), the actual yaw rate provided by the yaw rate detector 104 And the calculated target yaw rate is compared (S103) to determine whether the difference between the yaw rate is greater than or equal to the set reference value (S104).

In step S104, the controller 200 determines whether understeer or oversteer occurs when the difference between the yaw rates is equal to or greater than the set reference value (S105).

When it is determined in S105 that the understeer is generated, the controller 200 calculates torque of the turning inner ring (S106) and determines distribution torque for each wheel (S111).

If it is determined in S105 that the oversteer is generated, the controller 200 calculates torque of the turning outer ring (S107) and determines distribution torque for each wheel (S111).

If the difference in yaw rate is less than or equal to the reference value, the controller 200 compares the speed difference between the front wheel and the rear wheel (S108) and determines whether the speed difference between the front wheel and the rear wheel is greater than or equal to the reference value (S109).

In S109, the controller 200 determines a slip state when the speed difference between the front wheel and the rear wheel is equal to or greater than a set reference value, and calculates a slip torque according to the slip degree of each wheel (S110) to determine the distribution torque for each wheel (S111). ).

In addition, the control unit 200 detects a change in the height of the inner and outer shafts according to the turning provided by the height detecting unit 105 (S112), calculates the vertical drag from the change of the garage (S113), and drives the limit torque using the vertical drag. Determine (S114).

The calculation of the vertical force according to the height change can be performed as follows.

As can be seen in FIG. 3, when the vehicle is turned, load movement by the roll occurs from the inner ring to the outer ring, so that the height of each axle varies by the amount of movement of the vehicle load.

At this time, as can be seen in Figure 4 the magnitude of the vertical load is proportional to the size of the friction source, the vector sum of the driving force and the cornering force (Cornering Force) of the vehicle should be smaller than this.

In FIG. 3, the force acting on the tire may be expressed as a sum of driving force / braking force and cornering force, and cornering force means frictional force between the tire and the road surface in balance with the centrifugal force.

Therefore, the calculation of the vertical force at which each tire presses the ground is as follows.

N = K × (L-present height)

Here, K is an intrinsic constant that can be set for each vehicle by a spring constant (kgf / mm).

L is an intrinsic constant that can be set for each vehicle as the height (mm) at full rebound.

Accordingly, the frictional limit point can be found after calculating the vertical drag of each wheel by detecting the change in the height of each wheel.

Thereafter, the control unit 200 compares the driving limit torque calculated by using the distribution torque for each wheel and the vertical drag (S115) and determines whether the driving limit torque is larger than the distribution torque for each wheel (S116).

In S116, when the distribution torque for each wheel is greater than the driving limit torque, the control unit 200 applies the torque allocated to each wheel as the limit torque calculated from the vehicle change (S118) and applies the torque vectoring control value to the torque vectoring mechanism 300. Provided (S119).

In addition, in S116, when the distribution torque for each wheel is smaller than the driving limit torque, the controller 200 applies the torque allocated to each wheel as it is (S117) and provides the torque vectoring control value to the torque vectoring mechanism 300 (S119). ).

Accordingly, the torque vectoring mechanism 300 operates the planetary gear and the multi-plate clutch according to the control signal applied from the controller 200 to distribute the driving force of the front, rear, left, and right wheels to execute torque vectoring control.

For example, suppose that a vehicle with a weight of 1400 kg is turning at 0.5 G and the measured variation in the height of the garage is +100 mm, the spring constant of the vehicle is 12 (Kgf / mm), and the vehicle load distribution is 60:40.

The change in normal drag (N) is 12 × 10 = 120 Kg, the front wheel inner ring is 1400 × 0.6 / 2-120 = 300 kg (+100 mm), and the front wheel outer ring is 1400 × 0.6 / 2 + 120 = 540 kg (-100 mm), The rear wheels have 1400 × 0.4 / 2-120 = 160 kg (+100 mm) and the rear wheels have 1400 × 0.6 / 2 + 120 = 400 kg (-100 mm), so the cornering force for each axle = 1400 (full load) × 0.5 ( Transverse G) / 4 (four axles) = 175 kgf + α (load movement proportional).

Limit of driving force (slip angle 30 ㅀ), front wheel inner ring 300kg (+ 100mm) × cos30 = 259.8 kgf, front wheel outer ring 540kg (-100mm) × cos30 = 467kgf, rear wheel inner 160kgf (+ 100mm), rear wheel outer 400kgf (- 100 mm).

Therefore, the torque vectoring logic including the height sensor can increase the stability of the vehicle by limiting the driving torque by the amount according to each load movement.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various modifications and changes may be made without departing from the scope of the appended claims.

100: turning information detection unit 200: control unit
105: torque vectoring mechanism

Claims (11)

A turning information detection unit detecting turning information of the vehicle;
The distribution torque for each wheel is determined from the turning information, and the driving limit torque is determined by calculating the vertical force from the height change, and the final torque is determined according to the distribution torque and the magnitude of the driving limit torque, thereby allocating the driving force of torque vectoring. A control unit;
Torque vectoring mechanism for controlling the distribution of the torque applied to each wheel according to the control of the controller;
Torque vectoring system of a vehicle comprising a. The method of claim 1,
The turning information detection unit includes a steering angle detection unit that detects a steering angle and a steering direction;
A wheel speed detection unit detecting a speed for each wheel;
A lateral acceleration detector for detecting lateral acceleration of the vehicle;
Yaw rate detection unit for detecting the yaw moment of the vehicle;
A garage detection unit mounted on the axle of the vehicle and detecting a change in the height of each axle generated during the turning process of the vehicle;
Torque vectoring system of a vehicle comprising a. The method of claim 1,
The control unit calculates a target yaw rate using the steering angle, the speed of each wheel, and the lateral acceleration, and if the difference between the detected actual yaw rate and the calculated target yaw rate is less than or equal to the set reference value, the controller compares the speeds of the front wheel and the rear wheel to the slip state. And determine the distribution torque for each wheel by calculating the slip torque according to the slip degree of each wheel. The method of claim 1,
The control unit is a torque vectoring system of a vehicle, characterized in that the difference between the detected actual yaw rate and the calculated target yaw rate is equal to or greater than a set reference value, and if the understeer occurs, the torque of the turning inner wheel is calculated to determine the distribution torque for each wheel. . The method of claim 1,
The controller is a torque vectoring system of a vehicle, characterized in that the difference between the detected actual yaw rate and the calculated target yaw rate is more than the set reference value, and if the oversteering occurs, the torque of the turning outer ring is determined to determine the distribution torque for each wheel. . The method of claim 1,
The control unit calculates the vertical drag from the height change of the inside and outside shaft according to the turning provided by the garage detection unit, and calculates the drive limit torque using the vertical force. The method of claim 1,
The control unit compares the distribution torque for each wheel with the driving limit torque calculated by the vertical force, and when the distribution torque for each wheel is greater than the driving limit torque, the torque applied to each wheel is applied as the driving limit torque to control torque vectoring. Vehicle torque vectoring system. The method of claim 1,
The control unit compares the distribution torque for each wheel and the driving limit torque for calculating the vertical drag, and when the distribution torque for each wheel is smaller than the driving limit torque, the torque vectoring is controlled by applying the torque allocated to each wheel as it is. Torque vectoring system of the vehicle. Detecting slip information of the vehicle to determine slip torque of the wheel and distribution torque for each wheel;
Determining the driving limit torque by calculating the vertical force in the garage change;
When the distribution torque is greater than the drive limit torque by comparing the distribution torque and the magnitude of the drive limit torque, torque vectoring is controlled by applying the drive limit torque. When the distribution torque is less than the drive limit torque, torque vectoring is controlled by applying the distribution torque. process;
Torque vectoring system control method of a vehicle comprising a. 10. The method of claim 9,
The slip torque of the wheel is determined according to the speed difference when the speed difference between the front wheel and the rear wheel is more than the reference value, and the distribution torque for each wheel is determined by the turning inner wheel torque and the turning outer wheel torque according to the occurrence of understeer or oversteer. Torque vectoring system control method of a vehicle. Calculating a target yaw rate using the steering angle, the speed of each wheel, and the lateral acceleration, and determining whether a difference between the detected actual yaw rate and the calculated target yaw rate is greater than or equal to a set reference value;
If the difference between the actual yaw rate and the target yaw rate is less than or equal to the reference value, determining the slip state by comparing the speeds of the front and rear wheels, and calculating the slip torque according to the slip degree of each wheel to determine the distribution torque for each wheel;
If the difference between the actual yaw rate and the target yaw rate is greater than or equal to the reference value and understeer is generated, determining the torque distribution for each wheel by calculating the torque of the turning inner ring;
If the difference between the actual yaw rate and the calculated target yaw rate is greater than or equal to the set reference value, and oversteer occurs, determining the torque distribution for each wheel by calculating the torque of the turning outer ring;
Calculating the normal drag at the height change of the inner and outer shafts according to the turning, and calculating the driving limit torque using the vertical drag;
Controlling torque vectoring by applying torque allocated to each wheel as a driving limit torque when the distribution torque for each wheel is compared with the driving limit torque calculated by the vertical force, and the driving torque is greater than the driving limit torque;
Controlling torque vectoring by applying torque allocated to each wheel as it is if the distribution torque for each wheel is smaller than the driving limit torque by comparing the distribution torque for each wheel with the driving limit torque calculated from the vertical drag;
Torque vectoring system control method of a vehicle comprising a.

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