KR20110032707A - Method and system for assisting lane keeping - Google Patents

Abstract

PURPOSE: A lane keeping assist system is provided to sense error of vehicle position, lane curvature, and posture angle and to assist steering torque through the sensed information. CONSTITUTION: A lane keeping assist system comprises: a vehicle speed sensor for detecting vehicle speed; a lane sensing camera for obtaining vehicle position error, lane curvature, and posture angle with respect to the lane; a control unit(220) for calculating control value of assist steering torque and outputting the control value; and a steering driving unit for controlling assist steering torque by receiving the control value.

Description

Lane Keeping Assistance System and Method [Method and System for Assisting Lane Keeping}

Embodiments of the present invention relate to lane keeping assist systems and methods. More specifically, the lane maintenance assistance to detect the position error, the curvature of the lane, the attitude angle and to assist the steering torque of the vehicle by using the speed of the vehicle, the position error of the vehicle, the attitude angle and the curvature of the lane A system and method thereof are provided.

Lane Keeping Assist System (LKAS) is a system that assists the driving of a vehicle by generating steering torque so that the vehicle does not leave the lane by receiving lane information and vehicle position information from a lane detection camera mounted on the vehicle. .

In the conventional lane keeping assistance system, the steering torque assist amount transmitted to the electric power steering system (EPS) to calculate the position of the vehicle running on the road is calculated using the error value of the vehicle position on the road.

However, after steering torque assist, the behavior of the vehicle may vary depending on the speed of the vehicle and the angle of the vehicle with the lane.

1 is a view showing an example of the behavior of the vehicle in the case of using a conventional lane keeping assistance system.

When the speed of the vehicle is the same as in the case of FIGS. 1A, 1B and 1C, the lateral speed of the vehicle after the steering torque assist varies according to the attitude of the vehicle.

When driving toward the outside of the lane as shown in FIG. 1B rather than when the vehicle is running parallel to the lane as shown in FIG. The lane return speed of the vehicle after the assist increases. In particular, when the speed of the vehicle is greater than that of FIG. 1A and the driving direction of the vehicle is in the lane, as shown in FIG. have.

According to an exemplary embodiment of the present invention, the vehicle detects a position error, a curvature of a lane, and an attitude angle of a driving vehicle and assists the steering torque of the vehicle by using the speed of the vehicle, a position error of the vehicle, an attitude, and a curvature of the lane.

According to one embodiment of the present invention, a lane maintenance assistance system, the vehicle speed sensor for detecting a vehicle speed of the vehicle; A lane detection camera for generating a vehicle position error, a curvature of a lane, and an attitude angle formed with a lane on a road on which the vehicle is driven; An assist steering torque is calculated using the vehicle position error (e) received from the lane detection camera, the curvature of the lane (γ), the attitude angle (ψ) and the vehicle speed (v) received from the vehicle speed sensor. A controller for outputting the assist steering torque; And a steering drive unit configured to control steering by receiving the assist steering torque from the control unit.

In addition, according to another embodiment of the present invention, a lane keeping assistance system, the lane detection camera for generating a vehicle position error, the curvature of the lane, the attitude angle with the lane on the road on which the vehicle is traveling; Using the curvature of the lane (γ) received from the lane detection camera to calculate the change rate of the lane curvature (γ '), the curvature of the lane (γ), the change rate of the curvature (γ'), the attitude angle (ψ) to the lane And calculating the transverse error e _la of the future trajectory with respect to the preset forward distance d _la using the position error e of the vehicle, and calculating assist steering torque proportional to the future trajectory transverse error. A control unit for outputting assist steering torque; And a steering drive unit configured to control steering by receiving the assist steering torque from the control unit.

Further, according to another embodiment of the present invention, a lane keeping assistance method, comprising: detecting a vehicle speed of a vehicle; Generating a vehicle position error, a curvature of the lane, and an attitude angle formed with the lane on a road on which the vehicle is traveling; Calculating assist steering torque using the vehicle position error (e), the curvature of the lane (γ), the attitude angle (ψ) and the vehicle speed (v); Outputting the assist steering torque; And receiving the assist steering torque to control steering.

According to another exemplary embodiment of the present invention, there is provided a lane maintenance assistance method, comprising: generating a vehicle position error, a curvature of a lane, and an attitude angle formed with a lane on a road on which a vehicle is traveling; Calculating a rate of change (γ ') of the lane curvature using the curvature of the lane (γ); The lateral error of the future trajectory with respect to the preset forward distance d _la using the curvature γ of the lane, the rate of change of the curvature γ ', the attitude angle ψ, and the position error e. e _la ) and calculating assist steering torque proportional to the future trajectory transverse error; Outputting the assist steering torque; And receiving the assist steering torque to control steering.

Hereinafter, some embodiments of the present invention will be described in detail through 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 describing the embodiments of the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

2 is a block diagram illustrating a lane keeping assist system according to a first embodiment of the present invention.

As shown in FIG. 2, the lane keeping assistance system according to the first embodiment of the present invention includes a lane detecting camera 212, a vehicle speed sensor 214, a controller 220, and a steering driving device. As the driving device, EPS 230 is used.

The lane detection camera 212 is mounted on the vehicle to generate vehicle position error, lane curvature, and attitude angle information forming the lane on the road on which the vehicle is traveling. Here, the position error means a distance away from the center of the lane on the basis of the lane detection camera 212, the curvature of the lane means the curvature of the lane at the current position of the lane detection camera 212, the attitude angle of the vehicle It means the angle that the direction makes with the lane.

The vehicle speed sensor 214 detects a vehicle speed of the vehicle.

The controller 220 receives vehicle position error, lane curvature, and attitude angle information of the lane from the lane detection camera 212 and receives the vehicle speed from the vehicle speed sensor 214 to assist assist steering torque. It calculates and outputs it to EPS230.

The EPS 230 controls steering by receiving assist steering torque from the controller 220.

3 is a diagram illustrating a positional relationship between a lane and a vehicle in the lane keeping assisting system according to a first embodiment of the present invention, and FIG. 4 is a diagram illustrating a positional relationship between a lane detecting camera 212 and a lane. to be.

As shown in FIGS. 3 and 4, the control unit 220 determines the vehicle position error received from the lane detection camera 212 by e, the curvature of the lane γ, and the speed of the vehicle received from the vehicle speed sensor by v (v Assume that the direction steering component v _y and the lateral velocity component v _x ), the assist steering torque (T _a ) can be obtained as shown in Equation (1).

T _a = k ₁ * e + k ₂ * v _x + k ₃ * γ (where k ₁ , k ₂ and k ₃ are proportional constants)

At this time, when the control unit 220 assumes the posture angle formed by the lane received from the lane detection camera 212 as ψ, the lateral velocity of the vehicle is (v _x = v * sinψ). do.

T _a = k ₁ * e + k ₂ * v * sinψ + k ₃ * γ

By calculating the assist steering torque as shown in Equation 2, not only the position error of the vehicle and the curvature of the lane, but also the speed of the vehicle and the attitude angle formed by the vehicle can be simultaneously used.

The assist steering torque may not be calculated when the vehicle position error e is smaller than the critical control distance l _a by setting a point away from the center of the lane (ie, _{a a} ) as the critical control distance.

5 is a block diagram illustrating a lane keeping assistance system according to a second embodiment of the present invention.

As shown in FIG. 5, the lane keeping assistance system according to the second embodiment of the present invention includes a lane detecting camera 212, a control unit 220, and a steering driving device. In this embodiment, the steering driving device includes an EPS ( 230).

The functions of the lane detection camera 212 and the EPS 230 in this embodiment are the same as the functions of the lane detection camera 212 and the EPS 230 in the lane keeping assist system according to the first embodiment of the present invention. .

In the present embodiment, the control unit 220 calculates the change rate of the lane curvature γ 'using the lane curvature γ received from the lane detection camera 212, the lane curvature γ, the rate of change of curvature ( γ '), the posture angle (ψ) with the lane, and the position error (e) of the vehicle, are used to calculate the transverse error (e _la ) of the future trajectory with respect to the preset forward distance (d _la ). Assist steering torque can also be calculated.

FIG. 6 is a diagram illustrating a positional relationship between a lane and a vehicle in the lane keeping assistance system according to the second embodiment of the present invention.

When the preset forward distance is called d _la , the lateral error e _la of the future trajectory can be calculated from Equation 3.

e _la = e + d _la * ψ + d _la ² * γ + d _la ³ * γ '

Therefore, the assist steering torque T _a may be calculated to have a value proportional to the future trajectory lateral error e _la as shown in Equation 4.

T _a = k * e _la = k * (e + d _la * ψ + d _la ² * γ + d _la ³ * γ '), where k is proportional constant

Even in this case, the assist steering torque can be calculated only when the vehicle position error e is larger than the critical control distance l _a by setting a point away from the center of the lane (ie, _{a a} ) as the critical control distance.

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

A lane keeping assisting method according to a first embodiment of the present invention will be described with reference to FIGS. 2 to 4.

As shown in FIG. 7, the lane keeping assistance method according to the first exemplary embodiment of the present invention first detects the vehicle speed of the vehicle from the vehicle speed sensor 214 (S702), and uses the lane detection camera 212 on the road on which the vehicle is driving. Receives a vehicle position error, the curvature of the lane, the attitude angle with the lane is received (S704).

Check whether the received vehicle position error exceeds the threshold control distance (S706), and if the vehicle position error exceeds the threshold control distance, the vehicle position error (e), the curvature of the lane (γ), the attitude angle (ψ) and The assist steering torque is calculated using the vehicle speed v (S708).

The calculated assist steering torque is output to the EPS 230 and the EPS ECU (Electronic Control Unit) 232 drives the EPS driver 234 to control steering (S710).

8 is a flowchart illustrating a lane keeping assistance method according to a second embodiment of the present invention.

A lane keeping assisting method according to a second embodiment of the present invention will be described with reference to FIGS. 5 to 6.

As shown in FIG. 8, the lane keeping assistance method according to the first exemplary embodiment of the present invention first receives a vehicle position error, a curvature of a lane, and an attitude angle formed by a lane from a lane detection camera 212. (S802).

Check whether the received vehicle position error exceeds the threshold control distance (S804), and if the vehicle position error exceeds the threshold control distance, calculate the rate of change (γ ') of the lane curvature using the curvature γ of the lane. Lateral error of the future trajectory (e _la ) with respect to the preset forward distance (d _la ) using the curvature of the lane (γ), the rate of change of the curvature (γ '), the attitude angle (ψ), and the position error (e). To calculate (S806).

After calculating the future trajectory lateral error, the assist steering torque proportional to the future trajectory lateral error is calculated (S808).

The calculated assist steering torque is output to the EPS 230 and the EPS ECU 232 drives the EPS driver 234 to control steering (S810).

As described above, according to an exemplary embodiment of the present invention, a lane detection camera mounted on a vehicle detects a position error, a curvature of a lane, and an attitude angle of a driving vehicle, and detects a vehicle speed, a position error of a vehicle, and an attitude angle. And assisting the steering torque of the vehicle by using the curvature of the lane, thereby increasing driving stability.

In the above description, all elements constituting the embodiments of the present invention are described as being combined or operating in combination, but the present invention is not necessarily limited to the embodiments. That is, all of the components may operate selectively in combination with one or more of them. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. 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. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In addition, the terms "comprise", "comprise", or "having" described above mean that the corresponding component may be embedded unless otherwise stated, and thus, other components. It should be construed that it may further include other components rather than to exclude them. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or excessively formal sense unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe 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.

1 is a view showing an example of the behavior of the vehicle in the case of using a conventional lane keeping assistance system,

2 is a block diagram illustrating a lane keeping assist system according to a first embodiment of the present invention;

3 is a diagram illustrating a positional relationship between a lane and a vehicle in the lane keeping assisting system according to a first embodiment of the present invention, and FIG. 4 is a diagram illustrating a positional relationship between a lane detecting camera 212 and a lane. ego,

5 is a block diagram illustrating a lane keeping assist system according to a second embodiment of the present invention;

6 is a diagram illustrating a positional relationship between a lane and a vehicle in the lane keeping assisting system according to the second embodiment of the present invention;

7 is a flowchart illustrating a lane keeping assistance method according to a first embodiment of the present invention;

8 is a flowchart illustrating a lane keeping assistance method according to a second embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

212: lane detection camera 214: vehicle speed sensor

220, 520: control unit 230: EPS

232: EPS ECU 234: EPS driver

Claims (7)

In the lane keeping assistance system, A vehicle speed sensor detecting a vehicle speed of the vehicle; A lane detection camera for generating a vehicle position error, a curvature of a lane, and an attitude angle formed with a lane on a road on which the vehicle is driven; An assist steering torque control value is obtained by using the vehicle position error (e) received from the lane detection camera, the curvature of the lane (γ), the attitude angle (ψ), and the vehicle speed (v) received from the vehicle speed sensor. A control unit for calculating and outputting the assist steering torque control value; And A steering drive unit for controlling steering by receiving the assist steering torque control value from the controller. Lane maintenance assistance system comprising a. The method of claim 1, The assist steering torque, T _a = k ₁ * e + k ₂ * v * sinψ + k ₃ * γ (where k ₁ , k ₂ and k ₃ are proportional constants) Lane maintenance assistance system, characterized in that calculated as. In the lane keeping assistance system, A lane detection camera for generating a vehicle position error, a curvature of a lane, and an attitude angle formed with a lane on a road on which the vehicle is driven; Using the curvature of the lane (γ) received from the lane detection camera to calculate the change rate of the lane curvature (γ '), the curvature of the lane (γ), the change rate of the curvature (γ'), the attitude angle (ψ) to the lane And calculating the transverse error e _la of the future trajectory with respect to the preset forward distance d _la using the position error e of the vehicle, and calculating assist steering torque proportional to the future trajectory transverse error. A control unit for outputting an assist steering torque control value; And A steering drive unit for controlling steering by receiving the assist steering torque control value from the controller. Lane maintenance assistance system comprising a. The method of claim 3, wherein The assist steering torque, T _a = k * e _la = k * (e + d _la * ψ + d _la ² * γ + d _la ³ * γ '), where k is proportional constant Lane maintenance assistance system, characterized in that calculated as. The method of claim 1 or 3, And the assist steering torque is calculated when the vehicle position error is greater than a critical position distance. In the lane keeping assistance method, Detecting a vehicle speed v of the vehicle and generating a vehicle position error e on the road on which the vehicle is traveling, a curvature of the lane, and an attitude angle ψ with the lane; Calculating an assist steering torque control value using the vehicle position error, the curvature of the lane, the attitude angle, and the vehicle speed; Outputting the assist steering torque control value; And Controlling steering by receiving the assist steering torque control value; Lane maintenance assistance method comprising a. In the lane keeping assistance method, Generating a vehicle position error, a curvature of the lane, and an attitude angle formed with the lane on a road on which the vehicle is traveling; Calculating a rate of change (γ ') of the lane curvature using the curvature of the lane (γ); The lateral error of the future trajectory with respect to the preset forward distance d _la using the curvature γ of the lane, the rate of change of the curvature γ ', the attitude angle ψ, and the position error e. e _la ) and calculating assist steering torque proportional to the future trajectory transverse error; Outputting the assist steering torque; And Controlling steering by receiving the assist steering torque; Lane maintenance assistance method comprising a.

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