KR101290973B1 - Lane centering method and lane centering system - Google Patents

Abstract

The present invention relates to a method and a system for following a road center, comprising: detecting lanes on both sides to obtain lane information including information on a road center, and grasping a vehicle state and vehicle behavior to include a vehicle center information; The controller acquires the information, and generates assist steering torque for causing the vehicle to follow the center of the road based on the lane information and the vehicle information, thereby performing the road center following control.

According to the present invention, there is an effect that allows the vehicle to safely drive while following the road center.

Road-centered, following

Description

Road-centered tracking method and system {LANE CENTERING METHOD AND LANE CENTERING SYSTEM}

One embodiment of the invention relates to a road centered tracking method and system. More specifically, the present invention relates to a technology that enables a vehicle to safely drive while following a road center.

Conventionally, a lane keeping assistance system (LKAS) is mounted on a vehicle so that the vehicle can travel without leaving the lane in which it is traveling.

The conventional lane keeping assistance system generates an assist steering torque to prevent the vehicle from leaving the driving lane, thereby performing a lane keeping function. The assist steering torque generated at this time does not occur when the vehicle is traveling within a certain distance from the center of the lane (ie, the road center). That is, only when the vehicle deviates from the center of the road, the assist steering torque is generated to perform the lane keeping function, and when the vehicle does not deviate from the center of the road, the assist steering torque is generated to maintain the lane. It does not perform a function.

However, even when the vehicle does not deviate from a certain distance from the center of the road, there are frequent situations where a lane keeping function is required. For example, such a situation may be the case where a vehicle driving in the side lane is driving adjacent to the own lane, or the width of the own lane is narrow. The conventional lane keeping assistance system does not perform the lane keeping function in the above-described exemplary situation, and thus, it is impossible to drive safely and may cause a collision between vehicles or a lane departure accident during driving.

Against this background, it is an object of the present invention to allow a vehicle to safely drive while following a road center.

In addition, another object of the present invention is to enable the vehicle to travel while adaptively estimating the road center smoothly and safely according to the vehicle condition and vehicle behavior, and the road condition (for example, road curvature) being driven.

An embodiment of the present invention, the lane information acquisition unit for detecting lanes of both sides of the vehicle to obtain lane information including information on the center of the road; A vehicle information acquisition unit for acquiring vehicle information including information on a vehicle center by identifying a vehicle state and vehicle behavior of the vehicle; An assist steering torque generation unit configured to calculate and generate assist steering torque based on the lane information and the vehicle information so that the vehicle does not deviate from the center of the road by more than a predetermined distance; And a driving controller configured to perform driving control of the vehicle based on the assist steering torque.

In addition, an embodiment of the present invention, by detecting both lanes to obtain lane information including information on the center of the road; Obtaining vehicle information including information on a vehicle center by identifying a vehicle state and vehicle behavior; Generating assist steering torque to cause a vehicle to follow the road center based on the lane information and the vehicle information; And performing a driving control to cause the vehicle to follow the center of the road based on the final steering torque obtained by adding the assist steering torque and the input driver's steering torque to each other.

As described above, according to the present invention, there is an effect of allowing the vehicle to safely drive while following the road center.

In addition, according to the present invention, there is an effect that allows the vehicle to travel while adaptively estimating the center of the road smoothly and safely according to the vehicle condition and vehicle behavior and the road condition (for example, road curvature) being driven.

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 road center tracking system 100 according to an embodiment of the present invention.

As shown in FIG. 3, the road center tracking system 100 according to an embodiment of the present invention is a system for controlling the vehicle 300 to travel while following the road center 310 of the road being driven. . The road center tracking system 100 generates assist steering torque to prevent the vehicle 300 from escaping beyond a predetermined distance 320 which may be defined in the road center 310 or changed according to the road width. At the point where the vehicle 300 tries to deviate from the road center 310 by a predetermined distance 320 or more, the generated road steering 310 and the input driver steering torque may follow the road center 310. The driving control 3000 is performed through the steering control to perform the control.

Referring to FIG. 1, the road center tracking system 100 may detect lanes on both sides and acquire lane information including information on a road center 310, and a vehicle state and a vehicle. Vehicle information acquisition unit 140 for acquiring vehicle information including information on the vehicle center by grasping the behavior, and assist steering torque for causing the vehicle 300 to follow the road center 310 based on lane information and vehicle information. It includes an assist steering torque generation unit 150 for generating a.

The above-described lane information acquisition unit 120 detects both lanes on the left and right sides of the vehicle 300 through an image captured by the camera 110, and based on the detection result, the road center 310 and Obtain lane information including information about road curvature.

The above-described vehicle information acquisition unit 140, through the result of grasping the vehicle state and vehicle behavior of the current vehicle 300, one of the lateral speed, longitudinal speed, yaw rate and heading angle Vehicle information including the above information is obtained through the vehicle information obtaining apparatus 130. Here, the vehicle information obtaining apparatus 130 may be various in-vehicle sensors and in-vehicle systems capable of measuring or storing lateral speed, longitudinal speed, yaw rate, heading angle, and the like. Various in-vehicle sensors may include, for example, one or more of a vehicle speed sensor, a yaw rate sensor, a steering angle sensor, and the like, and the in-vehicle system may include, for example, an antilock brake system (ABS) and an electronic stability control (ESC). The system may include one or more of an EMS, an Engine Management System (EMS), a Motor Driven Power Steering (MDPS) system, and the like.

The assist steering torque generation unit 150 calculates and generates assist steering torque that causes the vehicle 300 to follow the road center 310 without departing from the road center 310 by a predetermined distance or more. For example, based on the lane information obtained by the lane information obtaining unit 120 and the vehicle information obtained by the vehicle information obtaining unit 140, the center deviation distance error, which is a distance error between the road center 310 and the vehicle center, and the transverse direction Calculates the speed error and the target attitude angle change error, and assists the vehicle 300 to follow the center of the road 310 based on the calculated deviation distance error, the lateral speed error and the target attitude angle change error. Steering torque is calculated and generated. Here, referring to FIG. 3, the assist steering torque is steering torque that prevents the vehicle 300 from escaping beyond a predetermined distance 320 from the road center 310, and through this, driving for road center following. Control is performed.

The predetermined distance 320 mentioned above is information that can be adaptively changed according to a vehicle state or a road state. For example, the predetermined distance 320 is information that is changed larger or smaller by a value determined according to one or more of a vehicle speed, a vehicle width, a vehicle length, a road width (lane width), and a road curvature of the vehicle 300. . For example, when the road on which the vehicle 300 runs is a curved road having a large road curvature, the distance 300 is changed larger in the rotation center direction so that the vehicle 300 smoothly rotates the curved road, and thus the road center 310 ) Can be followed. In addition, when the vehicle speed of the vehicle 300 is fast, since it is easier to move away from the road center 310 than when it is slow, changing the predetermined distance 320 to a smaller distance may prevent the departure better.

A method of calculating the assist steering torque generated by the assist steering torque generation unit 150 for the road center following of the vehicle 300 will be described below.

The assist steering torque generation unit 150 calculates the "center deviation distance error", "lateral direction speed error" and "target posture angle change amount error", and calculates assist steering torque therefrom.

In order to calculate the assist steering torque, a lateral velocity error is calculated. The lateral velocity error is based on the lateral component of the attitude angle formed by the vehicle 300 and the detected two lanes, and the longitudinal velocity. Can be calculated.

Next, the "target attitude angle change amount error" for the assist steering torque calculation may be calculated from the difference between the target attitude angle change amount calculated from the longitudinal speed and the road curvature and the actual attitude angle change amount measured from the yaw rate sensor. .

Referring to FIG. 1, in the road center tracking system 100 according to an exemplary embodiment of the present invention, an assist steering calculated and generated by the assist steering torque generation unit 150 according to the above-described method is applied to the input driver steering torque. The driving control unit 160 may further include a driving control unit 160 that adds torque to obtain a final steering torque and performs driving control to cause the vehicle 300 to follow the road center 310 based on the final steering torque. That is, the assist steering torque calculated by the assist steering torque generation unit 150 for the road center following of the vehicle 300 is a driving control unit for controlling the running of the vehicle 300 for the road center following. Input to 160 is added to the driver's steering torque. The driving controller 160 may be a component included in a steering system such as motor driven power steering (MDPS).

In addition, the road center tracking system 100 according to an embodiment of the present invention may further include a switch for receiving information on whether the road center tracking function is used or not, and a display for displaying road center tracking status information. have.

The road center following system 100 according to the embodiment of the present invention described above may be implemented as an electronic control unit (ECU) for road center following. Such an electronic control unit is referred to as a LCS ECU (Lane Centering System Electronic Control Unit, hereinafter referred to as "LCS ECU"). As such, FIG. 2 illustrates that the road center tracking system 100 according to an embodiment of the present invention is implemented as an LCS ECU.

Referring to FIG. 2, when a driver inputs a driver through the switch 220 to use the road center tracking function, the LCS ECU 200 starts to perform the road center tracking function and includes a camera 110. The lane information of both lanes detected from the vision system 210 is input. In addition, at the same time, the LCS ECU 200 may include various in-vehicle sensors (e.g., vehicle speed sensor, yaw rate sensor, steering angle sensor 270, etc.) or various in-vehicle systems (e.g., ABS / ESC 140, MDPS 250). And vehicle information including at least one of a lateral velocity, a longitudinal velocity, a yaw rate, a heading angle, and the like, from the vehicle information obtaining apparatus 130 including the EMS 260 and the like.

Referring to FIG. 2, the LCS ECU 200 calculates and generates assist steering torque for allowing the vehicle 300 to follow the center of the road 310 using the input lane information and the vehicle information. In connection with 250, the driving of the vehicle 300 may be controlled to allow the vehicle 300 to follow the center of the road 310 based on the assist steering torque generated and the input driver steering torque. . The LCS ECU 200 may display the road center following state on the display 230 in the vehicle 300 while performing the road center following function so that the driver may check the current driving state of the vehicle 300. have.

Information or signals may be transferred between the devices shown in FIG. 2 through a vehicle communication network such as a control area network (CAN).

In the following, the above-described method of calculating assist steering torque will be described in more detail with reference to exemplary equations. When describing the assist steering torque calculation method with reference to these equations, the information used in the equations for calculating the assist steering torque is referred to together with FIG.

As shown in FIG. 3, the assist steering torque for the center of the road is a steering torque that prevents the vehicle 300 from escaping beyond the predetermined distance 320 from the center of the road 310. ) Is information that can be defined in advance or changed according to the road width. Such assist steering torque may be adaptively calculated according to the current vehicle condition and vehicle behavior, and may be expressed using Equation 1 as an example.

In Equation 1, T _a is assist steering torque, e _x is the center deviation distance error that is the distance error between the vehicle center and the road center 310, e _vx is the lateral speed error, e _{ψ '} is the target attitude angle The change amount error, k ₁ , k ₂ , k ₃ is a proportional constant.

In Equation 1, the transverse velocity error e _vx is first calculated by multiplying the transverse component of the posture angle formed by the lane and the vehicle 300 by the longitudinal velocity of the vehicle 300 to calculate the transverse velocity. It can be calculated by taking negative numbers for the lateral velocity. The lateral component of the posture angle formed by the lane and the vehicle 300 is a sine value of the posture angle formed by the lane and the vehicle 300. This calculation can be confirmed through Equation 2.

In Equation 2, e _vx is a lateral speed error, v _x is a lateral speed, v _v is a vehicle speed, and ψ is an attitude angle between the lane and the vehicle 300.

In Equation 1, the target attitude angle change error may be calculated from the difference between the target attitude angle change amount and the actual attitude angle change amount measured from the yaw rate sensor, as shown in Equation 3 below. Here, the target attitude angle change amount and the actual attitude angle change amount are derivative components of the attitude angle.

In Equation 3, e _{ψ '} is a target attitude angle change error, ψ' _des Is the target attitude angle change amount, and ψ 'is the actual attitude angle change amount measured from the yaw rate sensor.

In Equation 3, the target attitude angle change amount error e _{ψ '} can be calculated from the longitudinal velocity and the road curvature, as shown in Equation 4 below.

In Equation 4,? ' _Des is the target attitude angle change amount, v _y is the longitudinal speed of the vehicle 300, and γ is the road curvature (= 1 / R).

Equation 1 is obtained by using the lateral velocity error e _vx , target attitude angle change amount e _{ψ '} and target attitude angle change amount ψ' _des calculated through Equation 2, Equation 3 and Equation 4. In other words, the following equation (5).

Assist steering torque used in accordance with the above-described method for the road-oriented tracking in the road-oriented tracking system 100 according to an embodiment of the present invention, and lane keeping in the conventional lane keeping assistance system (LKAS) The assist steering torque used for calculation can be compared as in FIG. 5.

Figure 5 (a) showing the assist steering torque 510 is calculated and used for lane keeping in a conventional lane keeping assistance system (LKAS), and the road center tracking system according to an embodiment of the present invention ( Comparing FIG. 5 (b) showing the assist steering torque 520 calculated and used for the road center following in FIG. 100, the conventional lane keeping assistance system (LKAS) calculates lane maintenance. The assist steering torque 510 to be used is generated only when the lateral error (distance between the center of the vehicle and the center of the vehicle) is greater than or equal to a predetermined value. The assist steering torque 520 to be used in this manner can be seen that the lateral error (distance between the center of the road and the center of the vehicle) is zero at all values. This can enable safer road driving in lanes more strictly.

As described above, according to the present invention, there is an effect of allowing the vehicle to safely drive while following the road center.

In addition, according to the present invention, there is an effect that allows the vehicle to travel while adaptively estimating the center of the road smoothly and safely according to the vehicle condition and vehicle behavior and the road condition (for example, road curvature) being driven.

6 is a flowchart illustrating a road center tracking method provided by the road center tracking system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 6, the road center tracking method provided by the road center tracking system 100 according to an embodiment of the present disclosure may detect lanes on both sides and acquire lane information including information on the road center 310. Acquiring vehicle information including information on the vehicle center by identifying the vehicle state and the vehicle behavior (S602), and the vehicle 300 based on the lane information and the vehicle information (310). Generating assist steering torque to follow the step S604 and driving control to cause the vehicle 300 to follow the road center 310 based on the final steering torque obtained by adding the assist steering torque and the driver steering torque. Step S606 and the like.

In accordance with another aspect of the present invention, a road center tracking system includes a lane information acquisition unit that detects both lanes and obtains lane information including information on a road center, and grasps a vehicle state and a vehicle behavior for a vehicle center. A vehicle information acquisition unit for acquiring vehicle information including information, and an assist steering torque generation unit for calculating and generating assist steering torque based on lane information and vehicle information so that the vehicle does not deviate from the center of the road by more than a predetermined distance; And a driving control unit that performs driving control of the vehicle on the basis of the generated assist steering torque (as shown in FIG. 5B).

The above-mentioned predetermined distance refers to a separation distance between the vehicle and the road center, which is a criterion for determining whether the road center tracking is necessary, and is information that may be differently defined according to one or more of the vehicle speed and the road curvature. For example, when the vehicle speed is high, a criterion for determining whether the center of the road is required for smooth road center following control may be set by changing a predetermined distance shorter than when the vehicle speed is slow. In addition, when the road being driven is curved, that is, when the curvature is greater than or equal to a certain value, the criterion for determining whether the center of gravity of the road is required so that the vehicle can travel along the curved road is greatly changed by a certain distance. Can also be set.

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 meanings as commonly understood by one of ordinary skill in the art 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.

1 is a block diagram of a road center tracking system according to an embodiment of the present invention;

2 is an exemplary view of implementing a road center tracking system according to an embodiment of the present invention;

3 is an exemplary diagram in which a vehicle is controlled to follow a road center by a road center following system according to an embodiment of the present invention;

4 is a view for explaining a method for generating assist steering torque in a road center tracking system according to an embodiment of the present invention;

FIG. 5 is a view comparing assist steering torque in a road center tracking system and assist steering torque in a conventional lane keeping assistance system according to an embodiment of the present invention; FIG.

6 is a flowchart illustrating a road center tracking method according to an embodiment of the present invention.

Description of the Related Art

100: Lane Centering System (LCS)

110: camera 120: lane information acquisition unit

130: vehicle information acquisition device 140: vehicle information acquisition unit

150: assist steering torque generation unit 160: driving control unit

200: Lane Centering System Electronic Control Unit (LCS)

210: vision system 220: switch

230: display 300: vehicle

310: road center

Claims (7)

A lane information acquisition unit for detecting lanes on both sides of the vehicle and obtaining lane information including information on a road center; A vehicle information acquisition unit for acquiring vehicle information including information on a vehicle center by identifying a vehicle state and vehicle behavior of the vehicle; An assist steering torque generation unit configured to calculate and generate assist steering torque based on the lane information and the vehicle information so that the vehicle does not deviate from the center of the road by more than a predetermined distance; And And a driving controller configured to perform driving control of the vehicle based on the assist steering torque. The constant distance is, And the information is changed to be larger or smaller by a predetermined value according to one or more of a vehicle speed, a vehicle width, a vehicle length, a road width, and a road curvature of the vehicle. delete The method of claim 1, The lane information acquisition unit, Detecting both lanes on the left and right sides of the vehicle through an image captured by a camera, and obtaining lane information including information on the road center and road curvature based on a detection result; Road-based tracking system. The method of claim 1, The vehicle information acquisition unit, Acquiring the vehicle information including information on at least one of a lateral velocity, a longitudinal velocity, a yaw rate, and a heading angle, based on the results of the vehicle status and vehicle behavior of the current vehicle. Characterized by road-oriented tracking system. 5. The method of claim 4, The assist steering torque generation unit, Based on the lane information and the vehicle information, a center deviation distance error, a lateral velocity error, and a target attitude angle change error, which are distance errors between the road center and the vehicle center, are calculated; The assist steering torque for allowing the vehicle to follow the center of the road without departing from the center of the road more than the predetermined distance based on the calculated center deviation distance error, the lateral speed error and the target attitude angle change amount error. Road-oriented tracking system, characterized in that the calculation. 6. The method of claim 5, The assist steering torque generation unit, Calculate the transverse velocity error based on the transverse component of the attitude angle formed between the vehicle and the sensed lanes, and the longitudinal velocity; And calculating the target attitude angle change error from the difference between the target attitude angle change amount calculated from the longitudinal speed and the road curvature and the actual attitude angle change amount measured from the yaw rate sensor. Detecting lanes on both sides of the vehicle to obtain lane information including information on a road center; Acquiring vehicle information including information on a vehicle center by identifying a vehicle state and vehicle behavior of the vehicle; Calculating and generating assist steering torque based on the lane information and the vehicle information so that the vehicle does not deviate from the center of the road by more than a predetermined distance; And Performing driving control to cause the vehicle to follow the center of the road based on the final steering torque obtained by adding the assist steering torque and the input driver's steering torque, The constant distance is, And the information is changed to be larger or smaller by a predetermined value according to at least one of a vehicle speed, a vehicle width, a vehicle length, a road width, and a road curvature of the vehicle.

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