KR101224239B1 - Method and system for lane-keeping control - Google Patents

Abstract

The present invention relates to lane keeping control, and more particularly, to a lane keeping control method and system for stably and efficiently performing lane keeping control according to a predicted result by predicting a vehicle condition in advance of a predetermined distance. will be.

Description

Lane Keeping Control Method and System {METHOD AND SYSTEM FOR LANE-KEEPING CONTROL}

The present invention relates to lane keeping control, and more particularly, to a lane keeping control method and system for stably and efficiently performing lane keeping control according to a predicted result by predicting a vehicle condition in advance of a predetermined distance. will be.

As vehicles become intelligent these days, various control techniques have been applied to vehicles. Such various control technologies include lane keeping control technology that detects a lane using a camera and controls the vehicle not to leave the lane or controls the vehicle to follow the center of the lane by using the lane detection result.

However, in the conventional lane keeping control technology, delay time may occur due to various factors until the lane departure occurs and the control is actually performed, which may cause a problem of preventing lane departure.

In this background, it is an object of the present invention to efficiently perform lane keeping control based on the calculated forward head distance according to the vehicle condition.

Another object of the present invention is to predict the state of the vehicle ahead of a certain distance in advance so that the lane maintenance control is performed stably and efficiently according to the predicted result.

In order to achieve the above object, in one aspect, the present invention provides a lane keeping control system for calculating a forward peripheral distance based on the vehicle condition, and performing lane maintenance control based on the calculated forward peripheral distance. .

The lane keeping control system includes: an entry boundary arrival prediction time setting unit configured to set an entry boundary arrival prediction time for the vehicle to reach an entry boundary set for entry of lane keeping control for the vehicle; A forward peripheral distance calculation unit configured to calculate a forward peripheral distance based on the predicted arrival time and the vehicle speed; A lateral error calculator configured to calculate a lateral error of the vehicle predicted in front of the front view distance; A lane maintenance control entry determination unit determining whether to enter the lane keeping control based on the lateral error and the entry boundary line; The lane maintenance control torque generation unit for generating a lane maintenance control torque for causing the vehicle to return to the inside of the entry boundary when it is determined that the lane maintenance control should be entered; And a lane keeping control torque releasing unit for releasing the lane keeping control torque when it is determined that the vehicle has been returned to the inside of a release boundary set for release of the lane keeping control for the vehicle after the lane keeping control torque is generated. .

The above-described entry boundary arrival prediction time setting unit may set the entry boundary arrival prediction time to satisfy a system transmission characteristic condition defined by a camera data calculation cycle, a vehicle network transmission cycle, and a torque rise time.

The above-mentioned forward looking distance calculator may calculate the forward looking distance by multiplying the predicted arrival time of the arrival boundary line and the vehicle speed.

The above-described lateral error calculator may calculate the lateral error of the vehicle predicted in front of the front peripheral viewing distance based on the lane information obtained from the camera and the yaw rate of the vehicle.

The lane keeping control system described above connects a first point located at a first distance in an inward direction from a lane to set the entry boundary line, and connects a second point located at a second distance in an inward direction from the entry boundary line. The apparatus may further include a boundary line setting unit configured to set the release boundary line.

The boundary line setting unit described above may set the entrance boundary line based on the road width.

The boundary line setting unit may adjust a distance between the entrance boundary line and the release boundary line according to a road curvature.

In another aspect, the present invention provides a lane keeping control method provided by a lane keeping control system, comprising: calculating an entry boundary arrival predicted time required for the vehicle to reach an entrance boundary set for entry of lane keeping control for a vehicle; Calculating an entry boundary arrival prediction time; A forward peripheral distance calculation step of calculating a forward peripheral distance based on the predicted arrival time and the vehicle speed; A lateral error calculation step of calculating a lateral error of the vehicle predicted in front of the front view distance; Determining whether to enter the lane maintenance control based on the lateral error and the entrance boundary line; If it is determined that the lane keeping control is to be entered, the lane keeping control torque for performing the lane keeping control is generated by generating a lane keeping control torque for causing the vehicle to return to the inside of the entry boundary in the opposite direction. Developmental step; And when the vehicle is returned to the inside of a release boundary set for the release of the lane keeping control for the vehicle after the lane keeping control torque is generated, by releasing the lane keeping control torque, the lane keeping control is released. It provides a lane keeping control method comprising a lane keeping control torque release step.

As described above, according to the present invention, there is an effect of efficiently performing lane keeping control based on the calculated forward head distance according to the vehicle condition.

In addition, according to the present invention, there is an effect of performing a stable and efficient lane keeping control according to the predicted result by predicting the vehicle condition in advance in a certain distance.

As a result, it is possible to solve a problem that could not be achieved when the lane keeping control is required due to the delay time in the system.

In addition, according to the present invention, by performing the lane keeping control more precisely, it is possible to prevent the phenomenon that frequent entry and release of the lane keeping control occurs.

1 is a block diagram of a lane keeping control system according to an exemplary embodiment of the present invention.
2 is a diagram for describing lane keeping control by the lane keeping control system according to an exemplary embodiment of the present invention.
FIG. 3 is a diagram for describing a method of determining whether the lane keeping control is entered by the lane keeping control system according to an exemplary embodiment of the present invention, based on a forward peripheral distance and an entry boundary line.
4 is a graph showing an entrance boundary line, which is a reference for entering the lane keeping control, by the lane keeping control system according to an exemplary embodiment, with respect to the road width.
FIG. 5 is a diagram illustrating a release boundary line which serves as a reference for releasing lane keeping control by the lane keeping control system according to an exemplary embodiment of the present invention.
FIG. 6 is a graph illustrating an entry boundary line and a release boundary line as a reference for entering and releasing lane keeping control according to an embodiment of the present invention with respect to road curvature.
7 is a flowchart illustrating a lane keeping control method according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

1 is a block diagram of a lane keeping control system 100 according to an embodiment of the present invention.

In the lane keeping control system 100 according to the exemplary embodiment of the present invention illustrated in FIG. 1, the lane keeping control is entered based on the vehicle state predicted in front of the vehicle in consideration of the inherent time delay and the required time for the control rising. It is a system that generates the lane maintenance control torque required for the lane maintenance control when determining whether to enter the lane maintenance control accordingly.

Referring to FIG. 2, when the calculated lane heading distance is d1 based on a preset entrance boundary arrival time and a current vehicle speed, the lane keeping control system 100 predicts the vehicle ahead of the heading distance d1. It is predicted that the lateral error (also referred to as the lateral position value) of 200 will not reach the preset entry boundary line so as not to enter the lane keeping control.

On the other hand, the lane keeping control system 100, when the value of calculating the forward heading distance according to the preset entrance boundary arrival time and the current vehicle speed is d2, the lane keeping control system 100 of the vehicle 200 predicted in front of the front heading distance d2 By predicting that the lateral error will exceed a predetermined entry boundary, it is determined that the lane keeping control should be entered, and start generating the lane keeping control torque required for this.

In more detail, the lane keeping control system 100 according to an embodiment of the present invention, as shown in Figure 1, the vehicle reaches the "entry boundary line" set for the entry of the lane keeping control for the vehicle The entry boundary arrival prediction time setting unit 110 that sets the "entry boundary arrival prediction time" that is required to take, and the front peripheral viewing distance calculation unit 120 that calculates the "front direction viewing distance" based on the entry boundary arrival prediction time and the vehicle speed. And a lateral error calculator 130 that calculates a lateral error of the vehicle predicted in front of the front view distance, and a lane maintenance control entry that determines whether to enter the lane maintenance control based on the lateral error and the entry boundary line. If it is determined that the lane keeping control is to be entered, and the determination result 140 and the determination result, leaving the "lane holding control torque" for causing the vehicle to return to the inside of the entry boundary line Lane maintenance control torque generation unit 150 to generate in the direction and after maintaining the lane maintenance control torque, if it is determined that the vehicle returned to the inside of the "release boundary line" set for the release of the lane maintenance control for the vehicle lane maintenance control And a lane keeping control torque releasing unit 160 for releasing torque.

The above-described entry boundary arrival prediction time setting unit 110 predicts the entry boundary arrival to satisfy a system transfer characteristic condition as shown in Equation 1 below, which may be defined by a camera data operation period, a vehicle network transmission period, and a torque rise time. You can set the time.

In Equation 1, T _entry is an entry boundary arrival prediction time, t1 is a camera data calculation period, and t2 is a vehicle network transmission period. t3 is a torque rise time, and can be defined by the maximum torque tolerance and the maximum torque change rate. For example, the torque rise time may be a value obtained by dividing the maximum torque allowance by the maximum torque change rate.

The above-described forward peripheral distance calculator 120 calculates an entry boundary arrival time estimate T _entry and a current vehicle speed v set by the entry boundary arrival prediction time setting unit 110 as shown in Equation 2 below. By multiplying the forward peripheral distance (d) can be calculated.

The above-described horizontal error calculator 130 may include a front view distance calculator 120 based on lane information obtained from a camera (for example, location information of a center point of a road) and a yaw rate of a current vehicle. The transverse error of the vehicle predicted in front of the forward circumference can be calculated. Here, the lateral error may mean a distance away from a reference point (for example, a road center point), and if the position value of the reference point is zero, the distance of the lateral error remains as it is. Since it can be a value, a horizontal error can also be called a horizontal position value.

In addition, the above-described lateral error calculator 130 may calculate the lateral error of the vehicle that is predicted in front of the front peripheral viewing distance by reflecting the current behavior state of the vehicle when calculating the lateral error.

The above-described lateral error calculation method will be exemplarily described with reference to FIG. 3.

FIG. 3 is a diagram for describing a method of calculating a transverse error of a vehicle predicted in front of a front peripheral viewing distance by reflecting a current behavior state of the vehicle.

Referring to FIG. 3, when the reference point is referred to as a road center point, the lateral error calculation unit 130 obtains x (0), which is a lateral error of the road center point, through lane information or the like, or obtains from the lane information acquisition unit. You can get it by input.

The lateral error calculation unit 130 calculates the lateral error (distance away from the center of the road laterally from the road center point) at the front peripheral distance d in a straight line from the camera. At this time, the transverse error at the forward peripheral distance d in a straight line from a sensor such as a camera is referred to as x (c).

Thereafter, the lateral error calculator 130 predicts the lateral movement amount x (v) of the vehicle predicted in front of the front peripheral viewing distance d by reflecting the behavior of the vehicle. The transverse movement amount x (v) of the vehicle predicted in front of the front peripheral distance d may be calculated by Equation 3 below.

In Equation 3, d is the forward peripheral distance, YR is the yaw rate of the vehicle, v is the speed of the vehicle.

Next, the lateral error calculation unit 130 subtracts the lateral movement amount x (v) of the vehicle predicted from the obtained x (c), and calculates the lateral error X (d) of the vehicle predicted in front of the front view distance d. Finally it can be calculated. (That is, X (d) = x (c) -x (v))

On the other hand, the lane keeping control system 100 according to an embodiment of the present invention, as shown in Figure 1, connecting the first point at a first distance in the direction of the road from the lane to set the entry boundary line, The boundary line setting unit 170 may further include a boundary line setting unit 170 configured to connect the second point at a second distance in an inward direction of the road to set the release boundary line.

The lane keeping control may enter too frequently depending on how the boundary line setting unit 170 sets the entry boundary line. In particular, when the road width is narrow, the lateral error of the vehicle reaches the entrance boundary line too easily, so that frequent lane keeping control can be performed. Accordingly, the boundary line setting unit 170 needs to set the entry boundary line closely according to lane information such as road width and road curvature (which may be lane information obtained through a camera).

For example, the boundary line setting unit 170 may set an entrance boundary line based on the road width. Referring to FIG. 4, when the road width falls within a specific road width range, the first distance from the lane to the inside of the road may be set. The entry boundary line can be set such that the distance between the lane and the entry boundary line is proportional to the road width. That is, the narrower the road width, the shorter the first distance may be set to make the entrance boundary line closer to the lane, and the wider the road width, the longer the first distance may be set to make the entrance boundary line farther from the lane.

In addition, the boundary line setting unit 170 carefully adjusts the distance between the entry boundary line and the release boundary line in order to prevent unnecessary repeated entry and release of the lane keeping control in setting the entry boundary line and the release boundary line. You need to set it. For example, if the distance between the entry boundary line and the release boundary line is set too narrow, after the lane keeping control is entered, the entered lane keeping control can be easily released, and the lane keeping control released again can be easily entered.

Such frequent repetition of the entry and release of the lane keeping control may occur well on a road having a large road curvature, and may not occur well on a road having a small road curvature.

Taking advantage of the fact that the frequent repetition of the entry and release of the lane keeping control varies according to the road curvature, the boundary line setting unit 170 sets, for example, the entry boundary line and the release boundary line to coincide with the straight road. (See Fig. 5 (a)), in the curve road can be set so that the entry boundary line and the release boundary line does not coincide (see Fig. 5 (b)).

When the frequent repetition of the entry and release of the lane keeping control generalizes the setting of the entry boundary and the release boundary line using the fact that the frequency of occurrence varies according to the road curvature, the boundary line setting unit 170 determines the entry boundary line and the release boundary line according to the road curvature. You can adjust the distance between the boundary lines, and if the road curvature falls within a certain road curvature range, set the entry and release boundaries so that the distance between the entry and exit boundary lines is proportional to the road curvature. The distance can be adjusted (see FIG. 6).

The lane keeping control torque generating unit 150 described above has a lane error control after the lateral error of the vehicle reaches or exceeds the entry boundary line, and thus the lateral error of the vehicle re-enters the inside of the entry boundary line. When there is a vehicle between the release boundaries, and in the case of a curved road, torque is generated to follow the curved road in order to maintain the lane keeping control without releasing it.

Hereinafter, the lane keeping control method provided by the lane keeping control system 100 according to the exemplary embodiment of the present invention described above will be briefly described again.

7 is a flowchart illustrating a lane keeping control method according to an embodiment of the present invention.

Referring to FIG. 7, in the lane keeping control method according to an exemplary embodiment of the present invention, calculating an entry boundary arrival time estimate for the vehicle to reach an entrance boundary line set for entry of the lane keeping control for the vehicle (S700). Calculating a forward circumferential distance based on the estimated arrival time and vehicle speed (S702), calculating a lateral error of the vehicle predicted before the forward circumferential distance (S704), and a lateral error of the vehicle. Determining whether or not to enter the lane maintenance control on the basis of the entrance boundary line (S706) and, if it is determined that the lane maintenance control should be entered, the lane maintenance control torque is released to the vehicle to return to the inside of the entry boundary line By performing in the opposite direction (road center direction), the lane keeping control is performed (S708), and after the lane keeping control torque is generated, If it is determined in the inside of the turn is set to the release of the lane keep control borders that the vehicle is returned, by releasing the lane keep control torque, it comprises a step (S710) such as to turn off the lane keep control.

As described above, according to the present invention, there is an effect of efficiently performing lane keeping control based on the calculated forward head distance according to the vehicle condition.

In addition, according to the present invention, there is an effect of performing a stable and efficient lane keeping control according to the predicted result by predicting the vehicle condition in advance in a certain distance.

As a result, it is possible to solve a problem that could not be achieved when the lane keeping control is required due to the delay time in the system.

In addition, according to the present invention, by performing the lane keeping control more precisely, it is possible to prevent the phenomenon that frequent entry and release of the lane keeping control occurs.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented as one independent hardware, some or all of the components may be selectively combined to perform a part or all of the functions in one or a plurality of hardware. As shown in FIG. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing embodiments of the present invention. As the storage medium of the computer program, a magnetic recording medium, an optical recording medium, a carrier wave medium, or the like may be included.

It is also to be understood that the terms such as " comprises, "" comprising," or "having ", as used herein, mean that a component can be implanted unless specifically stated to the contrary. But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (14)

Calculate the forward looking distance based on the vehicle condition, and perform lane keeping control based on the calculated forward looking distance,
An entry boundary arrival prediction time setting unit that sets an entry boundary arrival prediction time for the vehicle to reach an entry boundary line set for entry of lane keeping control for the vehicle;
A forward peripheral distance calculation unit configured to calculate a forward peripheral distance based on the predicted arrival time and the vehicle speed;
A lateral error calculator configured to calculate a lateral error of the vehicle predicted in front of the front view distance;
A lane maintenance control entry determination unit determining whether to enter the lane keeping control based on the lateral error and the entry boundary line;
The lane maintenance control torque generation unit for generating a lane maintenance control torque for causing the vehicle to return to the inside of the entry boundary when it is determined that the lane maintenance control should be entered; And
And a lane keeping control torque releasing unit for releasing the lane keeping control torque when it is determined that the vehicle has been returned to an inside of a release boundary set for releasing lane keeping control for the vehicle after the lane keeping control torque is generated.
The entry boundary arrival prediction time setting unit sets the entry boundary arrival prediction time so as to satisfy a system transmission characteristic condition defined by a camera data calculation period, a vehicle network transmission period, and a torque rise time. . delete delete The method of claim 1,
The torque rise time is,
Lane maintaining control system, characterized in that defined by the maximum torque allowance and the maximum torque change rate. The method of claim 1,
The front peripheral distance calculation unit,
And calculating the forward peripheral distance by multiplying the predicted arrival time of the entrance boundary and the vehicle speed. The method of claim 1,
The lateral error calculation unit,
And a lateral error of the vehicle, which is predicted in front of the front peripheral viewing distance, based on the lane information obtained from the camera and the yaw rate of the vehicle. The method of claim 1,
A boundary line that connects a first point at a first distance in an inward direction from a lane to set the entrance boundary line, and a boundary line that connects a second point at a second distance in an inward direction from the entrance boundary line and sets it as the release boundary line. Lane keeping control system further comprising a setting unit. The method of claim 7, wherein
The border line setting unit,
And the entry boundary line is set based on a road width. 9. The method of claim 8,
The border line setting unit,
And when the road width falls within a specific road width range, setting the entrance boundary line such that the first distance from the lane toward the road inward direction is proportional to the road width. The method of claim 7, wherein
The border line setting unit,
And controlling the distance between the entrance boundary line and the release boundary line according to a road curvature. The method of claim 10,
The border line setting unit,
And when the road curvature falls within a specific road curvature range, setting the entry boundary line and the release boundary line so that a distance between the entry boundary line and the release boundary line is proportional to the road curvature. The method of claim 10,
The border line setting unit,
And the entry boundary line and the release boundary line coincide with each other on the straight road, and the entry boundary line and the release boundary line with the release boundary line. The method of claim 12,
The lane keeping control torque generating unit,
And when the vehicle is between the entry boundary line and the release boundary line on the curve road, generating a torque to follow the curve road. In the lane keeping control method provided by the lane keeping control system,
An entry boundary arrival prediction time calculation step of calculating an entry boundary arrival prediction time taken for the vehicle to reach an entry boundary line set for entry of lane keeping control for the vehicle;
A forward peripheral distance calculation step of calculating a forward peripheral distance based on the predicted arrival time and the vehicle speed;
A lateral error calculation step of calculating a lateral error of the vehicle predicted in front of a front peripheral viewing distance;
Determining whether to enter the lane maintenance control based on the lateral error and the entrance boundary line;
If it is determined that the lane keeping control is to be entered, the lane keeping control torque for performing the lane keeping control is generated by generating a lane keeping control torque for causing the vehicle to return to the inside of the entry boundary in the opposite direction. Developmental step; And
After the lane keeping control torque is generated, if it is determined that the vehicle has returned to the inside of the release boundary set for the release of the lane keeping control for the vehicle, the lane keeping control torque is released, thereby releasing the lane keeping control. Lane keeping control torque releasing step,
In the step of calculating the entry boundary arrival prediction time, the lane keeping control time is calculated so that the entry boundary arrival prediction time is calculated to satisfy the system transmission characteristic condition defined by the camera data calculation period, the vehicle network transmission period, and the torque rise time. Way.

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