KR20210125139A - Controlling Method and Apparatus for Electronic Stability Control system - Google Patents

Abstract

Disclosed are a method and a device for controlling an electronic stability control (ESC) system. According to one embodiment of the present disclosure, the method for controlling an ESC system performing deceleration control by forming braking pressure in each wheel of a vehicle comprises: a process of detecting driving information of the vehicle; a process of determining forward or backward driving of the vehicle; a process of calculating control volume and control timing of hydraulic pressure based on the driving information to determine a first control mode operated by the calculated control volume and the calculated control timing; a process of applying correction to the control volume and the control timing of the first control mode when it is determined that the vehicle drives backward to determine a second control mode operated by the corrected control volume and the corrected control timing; a process of determining whether power of the ESC system is turned on or off; and a process of controlling the hydraulic pressure transmitted to each wheel of the vehicle according to the first control mode when it is determined that the vehicle drives forward and the second control mode when it is determined that the vehicle drives backward.

Description

Control method and apparatus of ESC system {Controlling Method and Apparatus for Electronic Stability Control system}

The present disclosure relates to an ESC (Electronic Stability Control) system control method and apparatus. More particularly, it relates to a method for controlling an ESC system when a vehicle is reversing, and an apparatus therefor.

The content described in this section merely provides background information for the present disclosure and does not constitute the prior art.

The ESC (Electronic Stability Control) system refers to a system for securing driving stability of the vehicle by controlling the brake hydraulic pressure so that the driver can turn as intended when the vehicle turns. In general, a vehicle is equipped with various functions that can grasp the driving information of the vehicle, and among them, the ESC system controls the hydraulic pressure transmitted to each wheel based on the driving information. When the ESC system is activated, the vehicle can be steered safely and quickly according to the driver's intention, such as when an obstacle suddenly appears in front while driving or when the wheel loses grip with the road surface while turning.

On the other hand, when the vehicle is traveling in reverse, for example, when parking, if the road surface is in a low friction state, oversteer or understeer unintended by the driver may occur, so the ESC system needs to be operated. . In addition, at the time when autonomous driving becomes common, since the vehicle is electrified, it is possible to drive in reverse even on a general road, so the ESC system operation is necessary even when driving in reverse.

As prior art related thereto, there is disclosed Korean Patent Publication No. 10-2019-0108687 'Reverse Driving Assistant System of Vehicle and Control Method Thereof'.

However, since this prior art stores the forward exit path and follows the path when parking, if a sudden turn is required regardless of the driver's intention during parking, the stability of the vehicle cannot be secured. there is

In addition, when driving in reverse, most of the prior art designs are designed to operate only ABS (Anti-lock Brake System) and TCS (Traction Control System), so that an ESC system is not separately provided. Accordingly, there is a problem in that the behavior control performance of the vehicle is deteriorated when the vehicle travels in reverse on the road other than when the vehicle is parked.

Accordingly, the present disclosure is intended to solve these problems, and provides an ESC system control method and apparatus that can secure vehicle stability even when reverse parking at medium and low speed on a low-friction road surface or driving backward at medium speed or higher it has its purpose

Another object of the present invention is to provide an ESC system control method and apparatus with improved performance for controlling the behavior of a vehicle even when driving in reverse.

According to an embodiment of the present disclosure for achieving this object, in an ESC (Electronic Stability Control) system control method for performing deceleration control by forming braking pressure on each wheel of a vehicle, driving information of the vehicle (driving information) information); determining whether the vehicle is traveling forward or backward; determining a first control mode operating with the calculated control amount and the calculated control timing by calculating a control volume and control timing of hydraulic pressure based on the driving information; determining a second control mode operating with the corrected control amount and the corrected control time by applying correction to the control amount and control time of the first control mode when it is determined that the vehicle is traveling in reverse; determining whether the power of the ESC system is ON/OFF; and controlling the hydraulic pressure transmitted to each wheel of the vehicle according to the first control mode when it is determined that the vehicle travels forward and the second control mode when it is determined that the vehicle travels backward. It provides an ESC system control method characterized in that.

The process of detecting the driving information of the vehicle may include: detecting a wheel speed of the vehicle; detecting a yaw rate of the vehicle; detecting the acceleration of the vehicle; and detecting a steering angle of the vehicle.

)는 수학식

에 의해 산출되며, 상기

는 차량의 종방향 속도, 상기

은 전륜과 후륜 사이의 직선거리, 상기

는 특성 속도, 상기

는 조향각이고, The process of determining the first control mode may include calculating a limit yaw rate and an Ackerman yaw rate through wheel speed, yaw rate, acceleration, and steering angle; and calculating a target yaw rate based on the reflection ratio of the road surface limit and the Ackerman yaw rate, wherein the Ackerman yaw rate (

) is the formula

is calculated by

is the longitudinal speed of the vehicle, where

is the straight-line distance between the front and rear wheels,

is the characteristic speed, said

is the steering angle,

)는 수학식

에 의해 산출되며, 상기

는 차량의 횡방향 가속도, 상기

는 차량의 수직항력인 것을 특징으로 할 수 있다.The road surface limit (

) is the formula

is calculated by

is the lateral acceleration of the vehicle, where

may be characterized as the vertical drag of the vehicle.

after calculating the target yaw rate, calculating a control amount using a difference value between the yaw rate and the target yaw rate; and calculating a control point using the target yaw rate.

The process of determining the second control mode may include calculating a reverse driving control volume by performing gain correction for a difference value between a yaw rate and a target yaw rate; and calculating a reverse driving control timing by performing gain correction for the reflection ratio of the road surface limit and the Ackerman yaw rate.

The process of calculating the reverse control amount may include: a process of correcting a gain so that the control amount for the inside rear wheel is reduced when the vehicle is in an understeer state; and correcting a gain so that a control amount of an outside front wheel is increased when the vehicle is in an oversteer state.

The process of calculating the reverse control timing may include: a process of correcting a gain to advance the control timing when the vehicle is in an understeer state; And when the vehicle is in an oversteer state, it may include a process of correcting the gain to delay the control time.

According to an embodiment of the present disclosure, a driving information detecting unit for detecting driving information of a vehicle; a controller unit for controlling a control volume and a control timing of hydraulic pressure based on the information obtained from the driving information detection unit; and a hydraulic apparatus transmitting hydraulic pressure to each wheel of the vehicle under the control of the controller, wherein the controller calculates a control amount and control time of hydraulic pressure according to the driving information detected by the driving information detection unit to the control calculating unit (control calculating unit); a control correcting unit for correcting the control amount and control time calculated by the control calculation unit when the vehicle travels in reverse; an operation determining unit that determines whether the power of the ESC system is ON/OFF; and a hydraulic controller unit for controlling the hydraulic device based on the control amount and control time calculated by the control calculation unit or the control correction unit when the power of the ESC system is in an ON state It provides an ESC system control device.

The driving information detecting unit may include: a wheel speed sensor measuring a wheel rotation speed of the vehicle; a yaw rate sensor for measuring the yaw rate of the vehicle; an acceleration sensor for measuring the acceleration of the vehicle; and a steering angle sensor for measuring a steering angle of the vehicle.

)는 수학식

에 의해 산출되며, 상기

는 차량의 종방향 속도, 상기

은 전륜과 후륜 사이의 직선거리, 상기

는 특성속도, 상기

는 조향각이고, 상기 노면한계(

)는 수학식

에 의해 산출되며, 상기

는 차량의 횡방향 가속도, 상기

는 차량의 수직항력인 것을 특징으로 할 수 있다.The control calculation unit calculates a road surface limit and an Ackerman yaw rate through a wheel speed sensor, a yaw rate sensor, an acceleration sensor, and a steering angle sensor, and based on the reflection ratio of the road surface limit and the Ackerman yaw rate Calculate the target yaw rate, wherein the Ackerman yaw rate (

) is the formula

is calculated by

is the longitudinal speed of the vehicle, where

is the straight-line distance between the front and rear wheels,

is the characteristic speed, where

is the steering angle, and the road surface limit (

) is the formula

is calculated by

is the lateral acceleration of the vehicle, where

may be characterized as the vertical drag of the vehicle.

The control calculator may calculate a control amount using a difference value between the yaw rate and the target yaw rate, and may calculate a control point using the target yaw rate.

The control correction unit may calculate a reverse control amount by performing gain correction for a difference value between the yaw rate and the target yaw rate, but may calculate a reverse control time point by performing gain correction for a reflection ratio of the road surface limit and the Ackerman yaw rate.

The control correction unit may perform gain correction so that the amount of control for the inner rear wheels is reduced when the vehicle is in an understeer state, and may perform gain correction so that the amount of control for the outer front wheels is increased when the vehicle is in an oversteer state.

The control correction unit may perform gain correction to advance the control timing when the vehicle is in the understeer state, but may perform gain correction to delay the control timing when the vehicle is in the oversteer state.

As described above, according to the present embodiment, even when driving in reverse, as the ESC system operates, it is possible to prevent understeer or oversteer of the vehicle, thereby securing the stability of the vehicle.

In addition, when the vehicle is traveling in reverse, the ESC system is applied together with the ABS and TCS, thereby improving the performance of controlling the vehicle's behavior.

1 is a functional block diagram of an ESC system control apparatus according to an embodiment of the present disclosure.
FIG. 2 is a conceptual diagram illustrating understeer and oversteer states when the vehicle moves backward according to an embodiment of the present disclosure.
3 is a flowchart of a method for controlling an ESC system according to an embodiment of the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description thereof will be omitted.

In describing the components of the embodiment according to the present disclosure, reference numerals such as first, second, i), ii), a), b) may be used. These signs are only for distinguishing the elements from other elements, and the nature, order, or order of the elements are not limited by the signs. When a part in the specification 'includes' or 'includes' a certain component, it means that other components may be further included, rather than excluding other components, unless explicitly stated to the contrary. .

1 is a functional block diagram of an ESC system control apparatus according to an embodiment of the present disclosure.

Referring to FIG. 1 , the ESC system control apparatus according to an embodiment of the present disclosure includes all or all of a driving information detecting unit 100 , a controller unit 120 , and a hydraulic apparatus 140 . includes some

The driving information detection unit 100 detects driving information such as wheel speed, yaw rate, acceleration, and steering angle of the vehicle and transmits it to the controller 120 . The control unit 120 calculates the control amount and control time of the hydraulic pressure based on the detected driving information, and controls the hydraulic device 140 according to the calculated control amount and the control time. The hydraulic device 140 transmits hydraulic pressure to each wheel of the vehicle under the control of the controller 120 .

In order to detect the driving information, the driving information detection unit 100 includes a wheel speed sensor 102 , a yaw rate sensor 104 , an acceleration sensor 106 , and a steering angle sensor. , 108) in whole or in part.

A total of four wheel speed sensors 102 are disposed on each wheel of the vehicle, and may measure not only the rotational speed of the wheel but also the speed of the vehicle through a change in a magnetic field generated while the wheel rotates.

The yaw rate sensor 104 may measure an angular speed of rotation with respect to a vertical axis of the vehicle, that is, a yaw rate. The yaw rate sensor 104 is located at the front of the vehicle, and whether the vehicle is in an understeer state or over is based on a target yaw rate calculated based on driving information different from the yaw rate measured by the yaw rate sensor 104 . It can be determined whether the state is oversteer.

The acceleration sensor 106 measures the lateral acceleration of the vehicle. However, the present invention is not limited thereto, and the longitudinal acceleration of the vehicle may be measured. The slip phenomenon of the tire can be detected through the measured lateral acceleration, and the surface condition of the road surface can also be determined. In order to measure the lateral acceleration, the acceleration sensor 106 is preferably located at the center of gravity of the vehicle, but is not limited thereto.

The steering angle sensor 108 is located at the lower end of the steering wheel, and may measure the adjustment speed and angle of the steering wheel when the driver controls the steering wheel. Through the measured speed and angle, it is possible to determine the driver's intention to turn.

Values measured from the wheel speed sensor 102 , the yaw rate sensor 104 , the acceleration sensor 106 , and the steering angle sensor 108 are transmitted to the controller 120 .

The control unit 120 includes all of a control calculating unit 122 , a control correcting unit 124 , an operation determining unit 126 , and a hydraulic controller unit 128 . or includes some.

The control calculator 122 calculates a control volume and control timing of hydraulic pressure based on the driving information detected by the driving information detection unit 100 . The control amount and control time of the hydraulic pressure calculated by the control calculation unit 122 correspond to the first control mode.

The control calculator 122 uses the values measured from the wheel speed sensor 102 , the yaw rate sensor 104 , the acceleration sensor 106 , and the steering angle sensor 108 to calculate the control amount and control time of the hydraulic pressure. Ackerman yaw rate and limit yaw rate can be calculated. Here, the Ackerman yaw rate is a numerical value indicating the amount of turning intended by the driver, and the road surface limit is a numerical value indicating the limit at which the wheel can maintain traction with the road surface.

)는 수학식 1에 의해 산출된다.In this case, Ackerman yawrate (

) is calculated by Equation 1.

는 차량의 종방향 속도,

은 전륜과 후륜 사이의 직선거리,

는 특성 속도,

는 조향각을 의미한다. 특성 속도란 운전자에게 요구되는 조향각이 애커먼 각도의 2배가 되는 시점의 차량 속도를 말한다. 애커먼 각도는 차량이 선회하는데 필요한 이상적인 조향각을 의미한다. here,

is the longitudinal speed of the vehicle,

is the straight-line distance between the front and rear wheels,

is the characteristic speed,

is the steering angle. The characteristic speed refers to the vehicle speed at which the steering angle required by the driver becomes twice the Ackerman angle. The Ackerman angle refers to the ideal steering angle required for a vehicle to turn.

Since the Ackerman yaw rate has a negative value when the vehicle is reversing, it is preferable to calculate it as an absolute value in order to obtain the control amount and control time.

)는 수학식 2에 의해 산출된다.road limit (

) is calculated by Equation (2).

는 차량의 횡방향 가속도,

는 차량의 수직항력을 의미한다.here,

is the lateral acceleration of the vehicle,

is the vertical drag of the vehicle.

The control calculator 122 calculates the target yaw rate by adjusting the reflection ratio of the Ackerman yaw rate and the road surface limit calculated by Equations 1 and 2 .

The hydraulic control amount is calculated through a yaw rate error. Here, the yaw rate error refers to a difference value between the yaw rate measured by the yaw rate sensor 104 and the target yaw rate. The hydraulic control point is calculated using the target yaw rate.

The control correction unit 124 corrects the control amount and the control timing calculated by the control calculation unit 122 when the vehicle is traveling in reverse. Whether the vehicle is traveling in reverse may be determined based on the driving information detected by the driving information detection unit 100 .

The control amount and control time corrected by the control correction unit 124 correspond to the second control mode. Since the second control mode is calculated when the vehicle travels in reverse, the control amount by the second control mode becomes the reverse control amount, and the control time by the second control mode becomes the reverse control time.

The reverse control amount is calculated by multiplying the difference between the yaw rate and the target yaw rate measured by the yaw rate sensor 104 by a gain correction value. It is calculated by multiplying the gain correction value. When performing gain correction for the reflection ratio of the Ackerman yaw rate and road limit, the position of the yaw rate sensor 104 and the size of the turning radius are taken into consideration.

The control correction unit 124 compares the size of the yaw rate measured by the yaw rate sensor 104 with the target yaw rate, and when the measured yaw rate is greater than the target yaw rate, determines that the yaw rate is oversteer, and the measured yaw rate is If the target yaw rate is less than the target yaw rate, it is judged as understeer. The control correction unit 124 secures driving stability of the vehicle by performing different corrections according to whether the vehicle is in an understeer state or an oversteer state.

Since the reverse control amount and control time are obtained by correcting the control amount and control time of the first control mode, the data of the forward driving can be used, and thus, when the ESC system is applied, the memory overload phenomenon does not occur in the case of reverse driving.

The operation determination unit 126 determines whether the power of the ESC system is ON/OFF while the vehicle is driving. The driver can forcibly shut down the ESC system of the vehicle if necessary, such as when the wheel is buried in snow. Even if the time point is calculated, hydraulic control is not performed.

The hydraulic control unit 128 controls the hydraulic system 140 according to the control amount and control time calculated by the control calculation unit 122 and the control correction unit 124 when the power of the ESC system of the vehicle is in an ON state. That is, when the vehicle moves forward, the hydraulic pressure is controlled according to the control amount and control time according to the first control mode, and when the vehicle moves backward, the hydraulic pressure is controlled according to the control amount and the control time according to the second control mode.

FIG. 2 is a conceptual diagram illustrating understeer and oversteer states when the vehicle moves backward according to an embodiment of the present disclosure.

Referring to FIG. 2 , in the case of a reverse driving vehicle 200 , as opposed to a forward vehicle, a rear wheel becomes a steering wheel. That is, the steering wheel becomes a front wheel when moving forward, but becomes a rear wheel when moving backward. When the rear wheel becomes the steering wheel, it is driven in the same way as a forklift, and it can be driven sufficiently on a straight-line road with few sharply changing corners.

In the case of the reverse vehicle 200 , the direction of rotation of the steering wheel is also reversed compared to the case of driving forward through the same corner. Therefore, in order to obtain the control amount of the reverse vehicle 200, it is preferable to correct the control amount of the first control mode.

)의 경로를 따르는 것이 바람직하다. 다만, 노면이 저마찰로인 경우나 운전자가 급제동 또는 급가속을 하는 경우에는 후진 언더스티어(reverse driving understeer,

) 또는 후진 오버스티어(reverse driving oversteer,

)가 발생할 수 있다.When the reverse vehicle 200 turns, for stable turning, reverse driving neutral steer,

) is preferred. However, if the road surface is a low-friction road or if the driver brakes or accelerates rapidly, reverse driving understeer

) or reverse driving oversteer,

) may occur.

)는 후진 차량(200)의 전륜이 노면과의 접지력을 상실하는 상황이므로 내측 후륜(inside rear wheel, 210)에 제동을 가하면 안정적인 선회가 가능하다. 한편, 차량이 후진으로 주행하고 있는 도중 후진 언더스티어(

)가 발생하면 내측 후륜(210)의 방향과 차량 후방의 슬립 발생방향이 동일하므로 전진하는 경우보다 내측 후륜(210)의 제어량을 감소시킬 수 있다. reverse understeer (

) is a situation in which the front wheels of the reversing vehicle 200 lose traction with the road surface, so that stable turning is possible when braking is applied to the inside rear wheels 210 . On the other hand, while the vehicle is traveling in reverse, reverse understeer (

) occurs, since the direction of the inner rear wheel 210 and the slip generation direction at the rear of the vehicle are the same, the amount of control of the inner rear wheel 210 can be reduced compared to the case of moving forward.

That is, since the inner rear wheel 210 tries to turn inside the turning radius and the rear of the vehicle also slips in the same direction, it is possible to safely turn even if the braking force on the inner rear wheel 210 is reduced.

)는 후진 차량(200)의 후륜이 노면과의 접지력을 상실하는 상황이므로 외측 전륜(outside front wheel, 220)에 제동을 가하면 안정적인 선회가 가능하다. 한편, 차량이 후진으로 주행하고 있는 도중 후진 오버스티어(

)가 발생하면 외측 전륜(220)의 방향과 차량에 슬립이 발생하는 방향은 일치하지 않으므로 전진하는 경우보다 외측 전륜(220)의 제어량을 증가시키는 것이 바람직하다. reverse oversteer (

) is a situation in which the rear wheel of the reversing vehicle 200 loses traction with the road surface, so that stable turning is possible when braking is applied to the outside front wheel 220 . On the other hand, while the vehicle is traveling in reverse, reverse oversteer (

) occurs, the direction of the outer front wheel 220 and the direction in which slip occurs in the vehicle do not match, so it is preferable to increase the control amount of the outer front wheel 220 rather than moving forward.

That is, since the outer front wheel 220 tries to move forward and the front of the vehicle slips inside the turning radius, the direction of the rear wheels is reversed and the amount of control for the outer front wheels 220 is increased to enable stable turning.

)가 발생한 경우 내측 후륜(210)에 대한 제어량을 감소시킨다. 반면에, 제어보정부(124)는 후진 오버스티어(

)가 발생한 경우 외측 전륜(220)에 대한 제어량을 증가시킨다. The control correction unit 124 performs the reverse understeer (

) occurs, the amount of control for the inner rear wheel 210 is reduced. On the other hand, the control correction unit 124 reverses oversteer (

) occurs, the amount of control for the outer front wheel 220 is increased.

)의 경우에는 요레이트 센서(104)가 측정한 요레이트와 목표 요레이트의 차이값에 대해 감소 게인하고, 후진 오버스티어(

)의 경우에는 요레이트 센서(104)가 측정한 요레이트와 목표 요레이트의 차이값에 대해 증가 게인한다.That is, reverse understeer (

), a gain is reduced for the difference between the yaw rate measured by the yaw rate sensor 104 and the target yaw rate, and reverse oversteer (

), an increase is obtained for the difference value between the yaw rate measured by the yaw rate sensor 104 and the target yaw rate.

For the calculation of the control point, the position and the rotation radius of the yaw rate sensor 104 are considered. Since the yaw rate sensor 104 is generally located at the front of the vehicle, in the case of the reversing vehicle 200 , the position of the yaw rate sensor 104 is at the rear of the vehicle. In addition, when the rear wheel becomes the steering wheel, the turning radius becomes larger when compared with the case where the front wheel becomes the steering wheel. That is, even if the driver controls the steering wheel with the same steering angle, the turning radius is larger in the case of rear wheel steering than the case of front wheel steering.

Assuming that the steering wheel is adjusted with the same steering angle in forward and reverse, the turning radius is larger when driving in reverse, and the position of the yaw rate sensor 104 is also changed to the rear of the vehicle. Therefore, in order to calculate the control time of the reverse vehicle 200, it is preferable to correct the control time of the first control mode.

)의 경우에는 전륜조향으로 전진하는 경우와 대비해 요레이트 센서(104)가 후방에 위치하고 선회반경도 커지므로 늦은 제어시점으로 계산된다. 즉, 후진 차량(200)의 전륜이 노면과의 접지력을 상실한 상태에서 요레이트 센서(104)가 차량의 후방에 위치하면 전방에 위치할 때보다 둔감하게 반응할 수 있다. 또한, 선회반경이 전진 주행할 때보다 크므로 후진 언더스티어(

)의 경우 제어시점을 앞당기는 것이 바람직하다. 따라서, 후진 언더스티어(

)의 경우 제어시점을 앞당기도록 애커먼 요레이트 및 노면한계의 반영비율에 대해 게인 보정을 한다.reverse understeer (

) is calculated as a late control point because the yaw rate sensor 104 is located at the rear and the turning radius is also increased compared to the case of forward wheel steering. That is, when the yaw rate sensor 104 is located at the rear of the vehicle in a state in which the front wheels of the reverse vehicle 200 lose grip with the road surface, the response may be less sensitive than when the yaw rate sensor 104 is located at the front. Also, since the turning radius is larger than when driving forward, reverse understeer (

), it is desirable to advance the control time. Therefore, reverse understeer (

), gain correction is made for the reflection ratio of the Ackerman yaw rate and road limit to advance the control time.

)의 경우에는 전륜조향으로 전진하는 경우와 대비해 요레이트 센서(104)가 후방에 위치하고 선회반경도 커지므로 빠른 제어시점으로 계산된다. 즉, 후진 차량(200)의 후륜이 노면과의 접지력을 상실한 상태에서 요레이트 센서(104)가 차량의 후방에 위치하면 전방에 위치할 때보다 민감하게 반응할 수 있다. 또한, 선회반경이 전진 주행할 때보다 크므로 후진 오버스티어(

)의 경우 제어시점을 늦추는 것이 바람직하다. 따라서, 후진 오버스티어(

)의 경우 제어시점을 늦추기 위해 애커먼 요레이트 및 노면한계의 반영비율에 대해 게인 보정을 한다.reverse oversteer (

In the case of ), the yaw rate sensor 104 is located at the rear and the turning radius is also large, so it is calculated as a fast control point in comparison with the case of moving forward with the front wheel steering. That is, when the yaw rate sensor 104 is located at the rear of the vehicle in a state in which the rear wheels of the reversing vehicle 200 lose grip with the road surface, it may respond more sensitively than when located at the front. In addition, since the turning radius is larger than when driving forward, reverse oversteer (

), it is desirable to delay the control point. Therefore, reverse oversteer (

), in order to delay the control point, gain correction is made for the reflection ratio of the Ackerman yaw rate and road limit.

As described above, the control correction unit 124 corrects the control amount and control time of the hydraulic pressure according to the first control mode, so that the ESC system can operate even when traveling in reverse, and thus, the effect of securing the stability of the vehicle is increased. have. In particular, when the vehicle needs to be parked on a slippery surface such as a low-friction road surface in polar regions or a black ice road surface in a general area, or when reverse driving is required, an unintentional understeer or oversteer situation may occur. By operating the ESC system in this situation, it is possible to prevent the vehicle from sliding.

3 is a flowchart of a method for controlling an ESC system according to an embodiment of the present disclosure.

Referring to FIG. 3 , the driving information detecting unit 100 continuously detects driving information such as wheel speed, yaw rate, acceleration, and steering angle of the vehicle ( S300 ). The controller 120 determines whether the vehicle is traveling forward or backward ( S310 ). When it is determined that the vehicle is traveling forward, the first control mode is determined.

The control amount in the first control mode is calculated based on the yaw rate error, that is, the difference between the yaw rate measured by the yaw rate sensor 104 and the target yaw rate, and the control point is the reflection ratio of the Ackerman yaw rate and the road limit. It is calculated by calculating the target yaw rate by adjusting the yaw rate (S320).

When it is determined that the vehicle is traveling in reverse, the second control mode is determined. The control amount of the second control mode is calculated by gain correction for the yaw rate error of the first control mode. In the case of understeer, the gain correction reduces the amount of control for the inner rear wheel 210, and in the case of oversteer, the outside A gain correction for increasing the amount of control for the front wheel 220 is performed (S330).

The control time in the second control mode is calculated by gain correction for the reflection ratio of the first control mode. In the case of understeer, gain correction to move up the control time is controlled, and in the case of oversteer, the control time is controlled. A gain correction for delaying a viewpoint is performed (S330).

When the control amount and control time are calculated by the control calculation unit 122 and the control correction unit 124, the operation determination unit 126 determines whether the power of the ESC system is ON/OFF (S340).

When it is determined that the power of the ESC system is OFF, hydraulic control by the ESC system is not performed, and the driving information detection unit 100 continues to detect driving information of the vehicle.

When it is determined that the power of the ESC system is turned on, the hydraulic control unit 128 starts controlling the hydraulic system 140 according to the control amount and control time of the first control mode or the second control mode ( S350 ).

As described above, when the vehicle travels in reverse, the ESC system operates in addition to the ABS (Anti-lock Brake System) and TCS (Traction Control System), so that the vehicle's behavior can be controlled quickly. In particular, at a point in time when autonomous driving becomes common, it is preferable that the ESC system controls the behavior of the vehicle together with the ABS and TCS as in the present embodiment because the vehicle can be driven backward even on a general road.

The above description is merely illustrative of the technical idea of this embodiment, and various modifications and variations will be possible by those skilled in the art to which this embodiment belongs without departing from the essential characteristics of the present embodiment. Accordingly, the present embodiments are intended to explain rather than limit the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the following claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present embodiment.

: 후진 뉴트럴스티어

: 후진 언더스티어

: 후진 오버스티어100: driving information detection unit 102: wheel speed sensor 104: yaw rate sensor
106: acceleration sensor 108: steering angle sensor 120: control unit
122: control calculation unit 124: control correction unit 126: operation determination unit
128: hydraulic control unit 140: hydraulic system 200: reverse vehicle
210: inner rear wheel 220: outer front wheel

: reverse neutral steer

: reverse understeer

: reverse oversteer

Claims (14)

In the ESC (Electronic Stability Control) system control method for performing deceleration control by forming braking pressure on each wheel of a vehicle,
detecting driving information of the vehicle;
determining whether the vehicle is traveling forward or backward;
determining a first control mode operating with the calculated control amount and the calculated control timing by calculating a control volume and control timing of hydraulic pressure based on the driving information;
determining a second control mode operating with the corrected control amount and the corrected control time by applying correction to the control amount and control time of the first control mode when it is determined that the vehicle is traveling in reverse;
determining whether the power of the ESC system is ON/OFF; and
A process of controlling hydraulic pressure transmitted to each wheel of the vehicle according to the first control mode when it is determined that the vehicle travels forward and the second control mode when it is determined that the vehicle travels backward
ESC system control method comprising a. The method of claim 1,
The process of detecting the driving information of the vehicle,
detecting a wheel speed of the vehicle;
detecting a yaw rate of the vehicle;
detecting the acceleration of the vehicle; and
The process of detecting the steering angle of the vehicle
ESC system control method comprising a. 3. The method of claim 2,
The process of determining the first control mode includes:
calculating a limit yaw rate and an Ackerman yaw rate based on the wheel speed, the yaw rate, the acceleration, and the steering angle; and
Comprising the process of calculating a target yaw rate (target yaw rate) based on the reflection ratio of the road surface limit and the Ackerman yaw rate,
The Ackerman Yorrate (

) is the formula

is calculated by

is the longitudinal speed of the vehicle, where

is the straight-line distance between the front and rear wheels,

is the characteristic speed, where

is the steering angle,
The road surface limit (

) is the formula

is calculated by

is the lateral acceleration of the vehicle, where

is the ESC system control method, characterized in that the vertical drag of the vehicle. 4. The method of claim 3,
After calculating the target yaw rate,
calculating a control amount using a difference value between the yaw rate and the target yaw rate; and
The process of calculating a control point using the target yaw rate
ESC system control method comprising a. 5. The method of claim 4,
The process of determining the second control mode includes:
calculating a reverse driving control volume by gain-correcting a difference between the yaw rate and the target yaw rate; and
A process of calculating a reverse driving control timing by correcting a gain for the reflection ratio of the road surface limit and the Ackerman yaw rate
ESC system control method comprising a. 6. The method of claim 5,
The process of calculating the reverse control amount is,
a process of correcting a gain so that a control amount for an inside rear wheel is reduced when the vehicle is in an understeer state; and
A process of correcting a gain so that a control amount for an outside front wheel is increased when the vehicle is in an oversteer state
ESC system control method comprising a. 7. The method of claim 6,
The process of calculating the reverse control time is,
when the vehicle is in an understeer state, gain correction to move up a control point; and
When the vehicle is in the oversteer state, the process of correcting the gain to delay the control point.
ESC system control method comprising a. a driving information detecting unit for detecting driving information of the vehicle;
a controller unit for controlling a control volume and a control timing of hydraulic pressure based on the information obtained from the driving information detection unit; and
Including a hydraulic apparatus for transmitting hydraulic pressure to each wheel of the vehicle under the control of the control unit,
The control unit is
a control calculating unit for calculating a control amount and a control time of hydraulic pressure according to the driving information detected by the driving information detecting unit;
a control correcting unit for correcting the control amount and control time calculated by the control calculation unit when the vehicle travels in reverse;
an operation determining unit that determines whether the power of the ESC system is ON/OFF; and
When the power of the ESC system is in an ON state, a hydraulic controller unit for controlling the hydraulic device based on the control amount and control time calculated by the control calculation unit or the control correction unit.
ESC system control device comprising a. 9. The method of claim 8,
The driving information detection unit,
a wheel speed sensor for measuring a wheel rotation speed of the vehicle;
a yaw rate sensor for measuring the yaw rate of the vehicle;
an acceleration sensor for measuring the acceleration of the vehicle; and
A steering angle sensor for measuring a steering angle of the vehicle
ESC system control device comprising a. 10. The method of claim 9,
The control calculation unit,
Calculating a road surface limit and an Ackerman yaw rate through the wheel speed sensor, the yaw rate sensor, the acceleration sensor, and the steering angle sensor,
Calculating the target yaw rate based on the reflection ratio of the road surface limit and the Ackerman yaw rate,
The Ackerman Yorrate (

) is the formula

is calculated by

is the longitudinal speed of the vehicle, where

is the distance between the front and rear wheels, above

is the characteristic speed, said

is the steering angle,
The road surface limit (

) is the formula

is calculated by

is the lateral acceleration of the vehicle, where

ESC system control device, characterized in that the normal force of the vehicle. 11. The method of claim 10,
The control calculation unit,
A control amount is calculated using the difference between the yaw rate and the target yaw rate,
ESC system control device, characterized in that for calculating a control point using the target yaw rate. 12. The method of claim 11,
The control correction unit,
A reverse control amount is calculated by performing gain correction for the difference between the yaw rate and the target yaw rate,
The ESC system control device, characterized in that the reverse control time is calculated by correcting the gain for the reflection ratio of the road surface limit and the Ackerman yaw rate. 13. The method of claim 12,
The control correction unit,
When the vehicle is in an understeer state, the gain correction is performed so that the amount of control for the inner rear wheel is reduced,
The ESC system control device, characterized in that when the vehicle is in an oversteer state, gain correction is performed so that the amount of control for the outer front wheel is increased. 14. The method of claim 13,
The control correction unit,
When the vehicle is in an understeer state, the gain is corrected to advance the control time,
ESC system control device, characterized in that the gain correction to delay the control time when the vehicle is in an oversteer state.

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