KR20180136161A - Stability control system amd method in a vehicle - Google Patents

Abstract

The present invention provides a system and a method for controlling the posture of an automobile. The system for controlling the posture of an automobile according to one embodiment of the present invention comprises: a sensor unit for measuring the speed and acceleration of the automobile; and a control unit increasing the allowable speed when a wheel spin calculated based on the automotive speed is smaller than a first threshold value and deceleration obtained based on the automotive acceleration is smaller than a second threshold value in traction control system (TCS) operation.

Description

TECHNICAL FIELD [0001] The present invention relates to a vehicle control system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a system and method for controlling an attitude of a vehicle, and more particularly, to an electronic braking system and a control method thereof. More particularly, And a control method.

BACKGROUND ART [0002] Generally, an electronic attitude control system of a vehicle is for obtaining a strong and stable braking force by effectively preventing a slip phenomenon of a vehicle, and includes an anti-lock brake system (ABS) A traction control system (TCS: Traction Control System) that prevents slippage of the drive wheels when the vehicle suddenly rises or suddenly accelerates, a vehicle that stably maintains the running state of the vehicle by controlling the brake hydraulic pressure by combining the anti-lock brake system and traction control And an electronic stability control system (ESC).

The ESC system is basically designed to control the yawing behavior of the vehicle. It controls the braking device and the engine in a dangerous driving situation reaching the contact limit of the tire when the vehicle turns, Device.

Usually, when the vehicle is turning, an oversteer, which is a spin-out in which the vehicle rolls inward on the basis of a stable turning locus, or an understeer, which is a drift out, The stability of the vehicle is deteriorated.

In order to prevent this, the ESC system generates a compensating moment acting on the outer side of the vehicle by applying a braking force to the outer wheel of the front wheel during oversteering in which the vehicle is inwardly curled inward compared with the trajectory desired by the driver, In the understeer, the braking force is applied to the inner wheel of the rear wheel, which prevents the vehicle from leaning inward from the trajectory of the vehicle and, conversely, the vehicle is pushed out of the trajectory desired by the driver, Thereby preventing the vehicle from being pushed outwardly from a desired trajectory and keeping the trajectory of the vehicle in a stable state.

As described above, the ESC system ensures appropriate stability of the turning vehicle by applying appropriate braking pressures to the front and rear wheels, while securing the turning stability by controlling the TCS engine torque.

However, since the ESC system is applied according to the driver's acceleration intention, there are some drivers who want to make stable turning according to the driver tendency, but there are some drivers who are not satisfied with stable turning due to dynamic driving tendency.

That is, the conventional ESC system has a problem in that the torque is reduced at the present time when detecting the running over the limit of the road surface during turning, and the driver can not satisfy the demand of the driver who wants faster acceleration in the turning acceleration situation.

Korean Patent Publication No. 10-2007-0106130

In an embodiment of the present invention, in an attitude control system, a vehicle attitude control that reflects the driver's acceleration will be performed in accordance with sensing the driving behavior of the driver.

According to an aspect of the present invention, there is provided a control method for a vehicle, comprising: a sensor unit for measuring a speed and an acceleration of a vehicle; and a control unit for controlling, during operation of a TCS (Traction Control System), a wheel spin calculated based on the speed of the vehicle, And a control unit for increasing the permissible speed if the deceleration acquired based on the acceleration of the vehicle is smaller than the second threshold value.

Further, the sensor unit further measures a steering angle, the control unit calculates a turning radius based on the steering angle, calculates a road surface friction coefficient on the basis of the acceleration, calculates an allowable speed according to the turning radius and the road surface friction coefficient Can be calculated.

In addition, the controller may set the required time to the permissible speed to be shorter as the calculated road surface friction coefficient is larger.

Further, the control unit can calculate the allowable torque based on the allowable speed and the required time to the allowable speed.

According to another aspect of the present invention, there is provided a method for controlling a Traction Control System (TCS) of a vehicle, comprising: measuring a speed and an acceleration of the vehicle; Calculating a wheel spin based on the speed of the vehicle; And increasing the allowable speed if the calculated wheel spin is smaller than the first threshold value and the deceleration acquired based on the measured acceleration is smaller than the second threshold value have.

Further, the method may further include the step of measuring the steering angle, and the allowable speed may be calculated according to the turning radius calculated on the basis of the measured steering angle, and the road surface friction coefficient calculated on the basis of the acceleration.

Further, as the calculated road surface friction coefficient is larger, the required time to the permissible speed can be set shorter.

The method may further include calculating an allowable torque based on the allowable speed and the required time to the allowable speed.

In an embodiment of the present invention, in the posture control system, the vehicle posture control that reflects the driver's acceleration will be performed as the driver's propensity to drive is sensed.

1 is a block diagram of an attitude control system according to an embodiment.
2 is a graph showing a turning radius of the vehicle and a vehicle speed according to road surface friction according to an embodiment.
FIG. 3 is a graph showing a time to reach an allowable speed according to the road surface friction according to an embodiment.
4 is a graph showing the operation of the posture control system according to an embodiment.
5 is a flowchart for explaining an attitude control method according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the present invention to a person having ordinary skill in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. For the sake of clarity, the drawings are not drawn to scale, and the size of the elements may be slightly exaggerated to facilitate understanding.

1 is a block diagram of an attitude control system according to an embodiment.

Referring to FIG. 1, a vehicle posture control system 100 includes a sensor unit 110, a pedal sensing unit 120, an electronic control unit 130, and a driving unit 140.

First, the sensor unit 10 includes an acceleration sensor 11 for measuring the longitudinal acceleration and lateral acceleration of the vehicle, a steering angle sensor 112 for measuring the steering angle of the vehicle, and a speed sensor 113 for measuring the speed of the vehicle can do.

The sensor unit 10 may further include various sensors required to measure the attitude of the vehicle, in addition to the acceleration sensor 11, the steering angle sensor 112, and the speed sensor 113 shown in FIG.

First, the acceleration sensor 11 measures the acceleration of the vehicle, and may include a lateral acceleration sensor and a longitudinal acceleration sensor.

The steering angle sensor 112 measures the steering angle. (Not shown) included in the vehicle, and can detect the steering speed, the steering direction, and the steering angle of the steering wheel.

The speed sensor 113 can be installed inside the wheel of the vehicle to detect the rotational speed of the vehicle wheel.

The pedal sensing unit 120 includes a pedal sensor (not shown). The pedal sensing unit 120 includes a brake pedal sensor (not shown) installed on the brake pedal for sensing the driver's will to braking, And an excel pedal sensor (not shown).

Next, the electronic control unit 130 collectively controls the attitude control system 100 according to the present invention. Specifically, the electronic control unit 130 determines the driver's will to be accelerated based on the sensing signal received by the sensor unit 110 and the pedal sensing unit 120, And a memory for storing various data necessary for performing operations of the main processor 131 and the electronic control unit 130 to be performed.

Hereinafter, a control method of the main processor 131 will be described based on FIG. 2 and FIG.

FIG. 2 is a graph showing the turning radius of the vehicle and the vehicle speed according to the road surface friction according to an embodiment. FIG. 3 is a graph showing a time of arrival to an allowable speed according to the road surface friction according to an embodiment.

2, the main processor 131 calculates the turning radius of the vehicle based on the steering angle information obtained from the steering angle sensor 112 included in the sensor unit 110. [

The main processor 131 calculates friction information (road surface friction coefficient) between the road surface and the vehicle on which the vehicle is running based on the acceleration / deceleration information and the lateral acceleration information of the acceleration sensor 111 included in the sensor unit 110.

Thus, the main processor 131 can set the allowable speed according to the road friction information and the turning radius. For example, as shown in Fig. 2, when the road surface friction coefficient is 0.2 g, 0.5 g and 0.8, the allowable speed according to the turning radius can be set differently.

As described above, the larger the road surface friction and the larger the turning radius, the larger the permissible speed can be set.

This is because the main processor 131 has a tendency that the road surface friction is large and the turning radius is large and the posture of the vehicle becomes unstable. Therefore, the main processor 131 sets the allowable speed of the vehicle to be high,

Also, although not shown, the main processor 131 may display a graph that continuously increases in accordance with the calculated road surface friction coefficient. For example, when the road surface friction coefficient is 0.6 g, the main processor 131 can control the road surface friction coefficient to have an allowable speed greater than 0.5 g and an allowable speed smaller than 0.8 g.

Further, the main processor 131 can set the time required until the permissible speed is reached based on the calculated road surface friction coefficient.

Specifically, FIG. 3 is a graph showing the arrival time to an allowable speed according to the road surface friction coefficient. As shown in FIG. 3, the main processor 131 reduces the time for reaching the allowable speed obtained in FIG. 2 as the road surface friction coefficient increases, and reaches the allowable speed obtained in FIG. 2 as the road surface friction coefficient becomes smaller The time will be longer.

This is because the larger the road surface friction is, the less the tendency of the vehicle to become unstable, so that the main processor 131 can reflect the driving behavior of the driver as fast as possible.

As shown in FIG. 3, the arrival time to the allowable speed according to the road surface friction coefficient can be a linear shape that decreases as the road surface friction coefficient increases.

Next, the main processor 131 calculates an acceptable torque based on the allowable speed calculated in Fig. 2 and the required speed up to the allowable speed obtained in Fig. Specifically, the main processor 131 can calculate the allowable torque based on the following equation (1).

[Formula 1]

F = m * (V _t - V) / S _t

Where F is the allowable torque, m is the weight of the vehicle, V _t is the permissible velocity, V is the current velocity of the vehicle, and S _t is the time required up to the permissible velocity.

Therefore, the main processor 131 obtains the speed of the vehicle from the speed sensor 113 included in the sensor unit 110, and calculates the allowable torque based on [Equation 1].

That is, according to [Expression 1], the larger the required time to the allowable speed is, the smaller the required allowable torque is calculated, and the required allowable torque is calculated to be larger as the required time to allowable speed is shorter.

Next, the main processor 131 transmits the calculated allowable torque information to the driving unit 140 to operate the engine and the motor included in the driving unit.

The memory 132 may be a volatile memory such as a S-RAM or a D-RAM, as well as a flash memory, a ROM, an erasable programmable read only memory (EPROM) (Electrically Erasable Programmable Read Only Memory (EEPROM)).

The non-volatile memory may semi-permanently store a control program and control data for controlling the operation of the vehicle attitude control system 100, wherein the volatile memory temporarily retrieves control programs and control data from the non-volatile memory, And various control signals output from the main processor can be temporarily stored.

Next, the driving unit 140 includes an engine driving unit 141 and a motor driving unit 142.

The engine drive unit 141 and the motor drive unit 142 drive the engine and the motor to secure the calculated allowable torque in the electronic control unit 130. [

The configuration of the vehicle posture control system 100 according to the present invention has been described above.

Hereinafter, the operation of the vehicle attitude control system 100 according to the present invention will be described. 4 is a graph illustrating an operation of the posture control system according to an embodiment of the present invention, and FIG. 5 is a flowchart illustrating a posture control method according to an embodiment of the present invention.

Fig. 4 shows the TCS control on / off signal, the lateral acceleration, the steering angle, the allowable turning torque, the driver's requested torque, the engine torque and the vehicle speed with respect to time.

4, when the TCS control signal is turned on at time t1 [sec], the attitude control system 100 calculates the acceleration obtained in the sensor unit 110 And the turning allowable torque is calculated on the basis of the steering angle.

At this time, when the calculated wheel spin amount exceeds the preset threshold value, the TCS control is turned on so that the vehicle posture stabilization control can be performed.

Further, when the TCS control is performed, the vehicle posture control method according to the present invention is performed only when the driver is dynamic on the basis of the wheel spin of the vehicle and the vehicle deceleration.

That is, when the obtained wheel spin of the vehicle is smaller than the first threshold value set in advance and the deceleration of the vehicle is smaller than the second threshold value, the main processor 131 does not perform the deceleration running even when the driver turns the vehicle , It is determined that a dynamic running is to be performed, and the turning allowable torque can be set differently from the conventional TCS.

At this time, the wheel spin can calculate the wheel spin as it grasps the rotational speed of the wheel based on the acceleration sensor 111 and the speed sensor 113 included in the sensor unit 110 of the vehicle.

The driver's requested torque can be obtained based on the driver's pedaling power. That is, the driver's requested torque can be obtained through the pedal pressure measured by the pedal sensing unit 120.

However, the vehicle secures the engine torque at the maximum value of the turning allowance torque calculated by the main processor 131 in order to perform the turning acceleration driving while maintaining the stability of the minimum vehicle.

Accordingly, as shown in FIG. 4, the vehicle attitude control system 100 can secure an increased torque amount reflecting the tendency of the driver as compared with the conventional TCS control.

4, the vehicle attitude control system 100 can secure an allowable speed that reflects the tendency of the driver that is larger than the vehicle speed value in the conventional TCS control.

Next, FIG. 5 is a flowchart for explaining an attitude control method according to an embodiment.

First, the vehicle posture control system 100 according to the present invention calculates the wheel spin amount of the vehicle (1000). Thereafter, the posture control system 100 performs TCS control based on the calculated wheel spin amount (2000).

That is, the posture control system 100 may perform TCS control to prevent a case where the posture of the vehicle suddenly rises or slips of the drive wheels occur in a rapid acceleration.

However, if the calculated wheel spin amount is smaller than the preset first threshold value (example of 3000) and the deceleration of the vehicle is smaller than the preset second threshold value (example of 4000), the attitude control system 100 determines that the torque Amount increase control is performed (5000).

If the wheel spin amount calculated by the attitude control system 100 is greater than a first threshold value set in advance (NO in 3000) or the deceleration of the vehicle is greater than a preset second threshold value (NO in 4000) Normal TCS control is performed (7000).

At this time, the torque amount increase control of the attitude control system 100 can be performed by calculating the allowable torque based on the above-described Figs. 2, 3 and 1 (5000).

Specifically, the allowable torque can be calculated based on the current speed of the vehicle, the road surface friction coefficient, and the calculated permissible speed.

At this time, the posture control system 100 operates the engine drive unit 141 and the motor drive unit 142 in the vehicle posture control system 100 according to the calculated allowable torque. Specifically, the engine and the motor are driven to increase the torque amount to the allowable torque, and then the normal TCS control is performed (7000) after the arrival time (S _t ) up to the permissible speed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein; It will be understood that various modifications may be made without departing from the spirit and scope of the invention.

100: Vehicle attitude control system

Claims (9)

A sensor unit for measuring a speed and an acceleration of the vehicle;
When the wheel spin calculated based on the speed of the vehicle is smaller than the first threshold value and the deceleration obtained based on the acceleration of the vehicle is smaller than the second threshold value in the operation of the Traction Control System (TCS) And a control unit for increasing the vehicle speed. The method according to claim 1,
The sensor unit further measures the steering angle,
Wherein the control unit calculates a turning radius based on the steering angle, calculates a road surface friction coefficient based on the acceleration, and calculates an allowable speed based on the turning radius and the road surface friction coefficient. 3. The method of claim 2,
Wherein the controller sets the required time to the permissible speed to be shorter as the calculated road surface friction coefficient is larger. The method according to claim 2 or 3,
And the control unit calculates the allowable torque based on the allowable speed and the required time to the permissible speed. In a TCS (Traction Control System) operation of a vehicle,
Measuring a speed and an acceleration of the vehicle;
Calculating a wheel spin based on the speed of the vehicle; And
And increasing the permissible speed if the calculated wheel spin is smaller than the first threshold value and the deceleration acquired based on the measured acceleration is smaller than the second threshold value. 6. The method of claim 5,
Further comprising: measuring a steering angle,
Wherein the allowable speed is calculated according to a turning radius calculated on the basis of the measured steering angle and a road surface friction coefficient calculated on the basis of the acceleration. 6. The method of claim 5,
And sets the required time to the permissible speed to be shorter as the calculated road surface friction coefficient increases. The method according to claim 5 or 6,
And calculating an allowable torque based on the allowable speed and the required time to the allowable speed. 9. The method of claim 8,
And driving the motor included in the vehicle to secure the allowable torque.

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