KR20170135072A - Apparatus and Method for Detecting Wheel Alignment State of Vehicle - Google Patents

Abstract

The present invention relates to an apparatus and a method for sensing a wheel alignment state of a vehicle. According to the present invention, a straight driving state of a vehicle is checked by using information or navigation map information of surrounding objects which are recognized through a vehicle radar or a camera, and vehicle speed and yaw rate information, and a wheel alignment of the vehicle is determined by using an accumulated value of a steering angle measured in the straight driving state. As such, the present invention enables a driver to recognize and cope with a misalignment state of the wheel alignment in a driving course without a separate wheel alignment sensing device. The present invention comprises: a structure sensor unit; a steering angle sensor; a yaw rate sensor; a straight driving determination unit; and a wheel alignment state determination unit. Thus, the present invention is able to reduce damage to vehicles or risks of accidents due to wheel misalignment.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and a method for detecting a vehicle wheel alignment state,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting a wheel alignment of a vehicle, and more particularly to an apparatus and a method for detecting a wheel alignment state of a vehicle using sensors such as a radar and a camera of a vehicle and a road structure such as a guardrail will be.

The electric power steering apparatus of the vehicle includes a torque sensor for detecting a twist of the steering shaft connected to the steering wheel, an electric motor for rotating / moving the steering output shaft or the rack bar in cooperation with the steering output shaft or the rack bar, And a steering ECU for controlling the rotation of the electric motor.

This electric steering apparatus basically operates to rotate the electric motor by generating a steering assist current so as to be proportional to the steering torque in accordance with the driver's steering wheel operation. That is, a basic operation for assisting the driver's steering force is performed.

In addition, front wheels on both sides are connected to the end portions of the vehicle steering apparatus through a rack bar, a tie rod, and the like.

Such an alignment state of the front wheels can be expressed by wheel alignment or wheel alignment, and when the steering apparatus is in the neutral position, the front wheels must also be in a neutral state and this state can be expressed as a state in which the wheel alignment is normal.

The front wheels of the vehicle support the weight of the front part of the vehicle body and must be geometrically assembled correctly in order to assure the function of the steering device and to ensure stable running and accurate and quick steering operation. Whether the front wheels are aligned can be determined by toe-in, camber, caster, king pin angle, SET BACK, TRUST ANGLE and the like .

However, depending on the assembling process of the front wheels or the long running of the front wheels, wheel misalignment or front wheel non-alignment may occur in which the neutral of the steering device and the neutral of the front wheels do not coincide with each other in relation to the steering device.

As described above, when the vehicle travels while the wheel alignment is in an abnormal state of wheel misalignment, the steering stability is deteriorated, the operation of the steering wheel becomes difficult, and abnormal wear of the tire is caused.

Therefore, in order to detect and correct the wheel alignment state, there has been a disadvantage that it is inconvenient to use another inspection equipment or the like which is conventionally disposed in the maintenance center.

In addition, since the driver can not easily recognize the unaligned state of the wheel alignment, there is a problem that the vehicle stability in the running process can not be secured.

That is, the conventional wheel alignment measurement method is not a method of detecting an abnormality in a running vehicle but a method of using a specific device at a predetermined position. Therefore, the driver must feel an abnormality while driving to find out whether or not the wheel alignment abnormality I could.

However, since each driver has different sensitivities to feel more than wheel alignment, in the case of an insensitive driver, the driver can not correct the wheel alignment until the wheel alignment is greatly changed,

In view of the foregoing, it is an object of the present invention to provide an apparatus and method for detecting and alerting a vehicle wheel alignment state using a vehicle sensor such as a radar or a camera and a straight road structure.

Another object of the present invention is to determine a straight road condition by detecting a lane or a guard rail by using a radar sensor installed in a vehicle, to determine a straight running state of the vehicle using a vehicle speed and a yaw rate in a straight road, And an object of the present invention is to provide an apparatus and method for detecting the state of wheel alignment using steering angle information generated in a driving condition.

Another object of the present invention is to confirm the straight running state of the vehicle using the information of the nearby objects recognized by the vehicle radar or the camera or the navigation map information, the vehicle speed and the yaw rate information, And determining the state of the wheel alignment of the vehicle by using the calculated wheel alignment value.

In addition, when the abnormal state of the wheel alignment is detected by the above-mentioned method, it is aimed to notify the abnormal state of the wheel alignment of the vehicle continuously by alarming stepwise according to the abnormal state.

In order to accomplish the above object, according to an embodiment of the present invention, there is provided a structure detection apparatus comprising: a structure detection sensor unit installed inside or outside a vehicle to detect a road structure outside the vehicle; A steering angle sensor for measuring a steering angle which is a rotation angle of the steering wheel; A yaw rate sensor for measuring a yaw rate, which is a time variation of a yaw angle of the vehicle; A straight running determining unit for determining a curvature of a road structure in front of the vehicle by receiving a signal from the structure detecting sensor unit and determining whether the vehicle is running straightly according to a curvature of the road structure, Wow; And a wheel alignment state determiner for determining the state of the wheel alignment of the vehicle using the steering angle information measured in the straight running state.

According to another embodiment of the present invention, there is provided a navigation system comprising: a navigation device installed in a vehicle and including map information; A steering angle sensor for measuring a steering angle which is a rotation angle of the steering wheel; A yaw rate sensor for measuring a yaw rate of the vehicle; A straight travel determining unit for determining a road curvature of a road currently in operation using the map information received from the navigation device and determining whether the vehicle is traveling straight ahead in accordance with the road curvature, the vehicle traveling speed, and the yaw rate; And a wheel alignment state determiner for determining the state of the wheel alignment of the vehicle using the steering angle information measured in the straight running state.

According to another embodiment of the present invention, there is provided a vehicular navigation system including: a curvature determination step of determining a curvature of a road structure in front of a vehicle using a structure sensor unit including a radar or a camera; Determining whether the vehicle is going straight ahead or not based on the curvature of the road structure, the vehicle speed of the vehicle, and the yaw rate of the vehicle; And a wheel alignment state determination step of determining a state of wheel alignment of the vehicle using steering angle information measured in a straight running state.

According to the present invention as described below, there is an effect that the wheel alignment state of the vehicle can be detected by using sensors such as a radar and a camera installed in the vehicle and a linear structure outside the vehicle.

More specifically, a straight road condition is detected by detecting a linear structure such as a lane or a guard rail using a radar or a camera sensor installed in the vehicle, and the state of the wheel alignment is determined by using the vehicle speed, yaw rate, cumulative steering angle information, And notifying the driver of the information, there is an effect that the wheel alignment state can be continuously detected without a separate inspection equipment.

Thereby, it is possible to prevent the vehicle from being damaged or exposed to danger by wheel misalignment by inducing the driver to take measures against wheel alignment.

1 shows a mechanical arrangement between a steering wheel and a wheel to which the present invention can be applied.
2 shows an overall configuration of a wheel alignment state sensing apparatus according to an embodiment of the present invention.
FIG. 3 shows an embodiment of the wheel alignment state sensing method according to FIG.
4 shows an overall configuration of a wheel alignment state sensing apparatus according to another embodiment of the present invention.
FIG. 5 illustrates an embodiment of the wheel alignment state sensing method according to FIG.
6 shows an overall flow of a wheel alignment state sensing method according to an embodiment of the present invention.
FIG. 7 is a detailed flowchart of a straight running determination process according to the present invention, and FIG. 8 is a detailed flowchart of a wheel alignment state determination process.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if 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 describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may 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 shows a mechanical arrangement between a steering wheel and a wheel to which the present invention can be applied.

1, a vehicle steering apparatus to which the wheel alignment state detecting apparatus according to the present invention can be applied includes a steering wheel or steering wheel 101 disposed in a driver's seat, a steering shaft 105 connected to the steering wheel or steering wheel, A gear box 130 having a rack gear 110 and a pinion gear 120 for converting a rotational force input from the steering shaft 105 into a linear motion, And a rack-bar 140 connected to the rack gear 110.

Two wheels 160 are connected to the ends of the rack bars 140 of the steering apparatus via tie rods 150. The rack bars 140 are linearly moved according to the rotation of the steering wheel to deflect the wheels to the left and right Steering is performed.

The steering shaft 105 is composed of an input shaft and an output shaft and the input shaft is connected to the steering wheel 101 and the output shaft is connected to the rack- .

In such a vehicle steering apparatus, Motor Driven Power Steering (MDPS) or Electronic Power Steering (EPS), which assists the steering of the steering wheel by the force of an electric motor, may be used.

Although not shown, the vehicle steering apparatus includes a steering torque sensor 127 installed inside or outside the steering column 103 to sense a steering torque generated by the operation of the steering wheel 101, And a steering angle sensor 129 for sensing a corresponding steering angle.

The steering torque sensor 127 is a sensor for measuring a steering torque generated by twisting of the steering wheel, and a torque sensor using an absorption dynamometer sensor or a torsion bar may be used.

The absorption dynamometer sensor can be classified into electric, water, air, and solid friction dynamometers. The torque sensors include a magnetostrictive torque sensor, a strain gauged torque sensor, and a phase difference detection type torque sensor.

The steering angle sensor 129 is a sensor that measures whether the steering wheel is in a neutral state, that is, at a certain degree of angle in the reference point state corresponding to the straight ahead.

1, although the steering wheel 101 is in a neutral state (that is, the steering angle is zero), the wheel alignment state detecting apparatus according to the present invention is configured such that the wheel is not aligned in the front direction, To detect an alignment state or an abnormal state of wheel alignment and warn him.

2 shows an overall configuration of a wheel alignment state sensing apparatus according to an embodiment of the present invention.

The wheel alignment state detecting apparatus 200 according to the embodiment of FIG. 2 includes sensors such as a structure detecting sensor unit 210, a steering angle sensor 220 and a yaw rate sensor 230, And a wheel alignment state determiner 250 for determining a wheel alignment state using the steering angle information measured in the straight running state, And the like.

The structure detection sensor 210 may include a radar sensor 212 or a camera 214 and the road structure sensed by the sensor may be a guard rail located at one or more sides of the road, have.

The vehicle radar sensor 212 may include a radar transmitter and a receiver for receiving a reflected signal reflected from an obstacle and may analyze the magnitude, frequency, and phase shift of the reflected signal, The profile of the obstacle can be detected.

Such a radar sensor 212 is a sensor having a detection distance of about 100 m or more and a detection angle of about 30 degrees or more and is a sensor for detecting the presence or absence of a ground structure existing in front or a front side, Can be measured.

The camera 214 is an image sensor module that captures an image having a viewing angle toward the front of the vehicle attached to the vehicle windshield, and captures and analyzes images of several tens frames per second.

Such a camera sensor analyzes an image existing in the image by applying an edge algorithm to the photographed image, and analyzes whether the image is a lane or traffic information printed on the road.

That is, in the present invention, when the radar sensor 212 is used as the structure detection sensor unit 210, the road structure is a protruding structure such as a guard rail and a median separator that can be detected by a radar, .

In the present invention, when the camera 214 is used as the structure detection sensor unit 210, the road structure may be a radar-driven lane information by a camera.

Of course, depending on the image processing performance of the camera 214, it may be possible to detect a protruding road structure such as a guard rail or a median separator in the photographed image.

The radar sensor 212 or the camera module 214 may output information on the sensed road structure to a straight travel determining unit 240 to be described later, and the information on the road structure output at this time may be a curvature of the road structure Information.

The steering angle sensor 220 is a sensor for measuring the steering angle, which is the rotational angle of the steering wheel, and performs the function of outputting the instantaneous steering angle information measured every judgment period to the outside as described later.

As described with reference to FIG. 1, the steering angle sensor 220 can be a sensor used in a general steering apparatus, and thus a detailed description thereof will be omitted.

The yaw rate sensor 230 is a sensor for measuring the yaw rate, which is the rotational angle degree of rotation of the longitudinal center axis of the vehicle per hour.

Generally, the vehicle may include a yaw sensor for measuring the yawing angle of the vehicle, a longitudinal acceleration sensor, and a lateral acceleration sensor. In place of the yaw sensor, the yawing angle And a yaw rate sensor for measuring the rate.

The yaw rate sensor 230 that can be used in the present invention performs a function of transmitting a yaw rate value, which is instantaneously measured under the control of the following straight traveling determining unit 240, to the straight running determining unit.

The straight run determination unit 240 receives a signal from the structure detection sensor unit to determine the curvature of the road structure at the front of the vehicle, and determines whether or not the vehicle is going straight, according to the curvature of the road structure, Function.

Generally, road structures such as guard rails, median separators or driving lanes are installed or arranged in line with the direction of the road.

Therefore, the straight running determination unit 240 can recognize the curvature of the road structure sensed by the radar, camera, or the like. When the curvature of the road structure is equal to or greater than a predetermined curvature threshold value, It can be assumed that it is a road.

If it is determined that the curved road structure has a curvature equal to or greater than the critical curvature and the current road is a straight road, the straight running determining unit 240 determines whether or not the vehicle is running straight, based on the measured vehicle speed and yaw rate .

More specifically, the straight run determination unit 240 determines whether or not the vehicle is running straight ahead only when the curvature of the road structure is equal to or greater than the threshold curvature and the vehicle radius (Path Radius) calculated from the vehicle speed and yaw rate values is equal to or greater than the threshold radius .

The vehicle path radius can be determined by Equation 1 below, and the critical radius may be, for example, about 10000 m, but is not limited thereto.

[Equation 1]

는 요레이트값(degree/s)를 의미한다.In Equation (1), R is a vehicle path radius, V is a vehicle speed (m / s)

Means the yaw rate value (degree / s).

In the present invention, the vehicle path radius according to Equation (1) used in the straight-ahead running determination has a unit of m / degree, which means a running distance until the yaw angle of the vehicle changes by 1 degree.

Therefore, when the vehicle path radius R calculated from the vehicle speed and the yaw rate value is equal to or greater than a critical radius value of about 10,000 meters, the straight running determination unit 240 can determine that the vehicle is almost in the straight running state.

As described above, according to the embodiment of FIG. 2, it is possible to accurately determine whether the vehicle is going straight ahead or not by using only the curvature value, the vehicle speed and the yaw rate value of the road structure without the information indicating the specific positional relationship of the vehicle with the driving lane, .

Further, the straight running determination unit 240 may determine whether or not the vehicle is traveling straight ahead, only when the vehicle speed is equal to or greater than the critical vehicle speed and the yaw rate is equal to or less than the critical yaw rate.

If the vehicle is running at a low speed, there may be an error in determining whether to run straight ahead. If the yaw rate is more than a certain level, the heading angle of the vehicle is also temporarily changed.

Therefore, only when the vehicle speed is equal to or greater than the critical vehicle speed and the yaw rate is equal to or less than the critical yaw rate, it is possible to improve the accuracy of the straight running determination by determining whether or not the vehicle is running straight ahead.

The wheel alignment state determination unit 250 determines one of the state of the wheel alignment, that is, the steady state of the wheel alignment or the abnormal state of the wheel alignment, using the steering angle information measured through the steering angle sensor in the straight running state of the vehicle.

More specifically, the wheel alignment state determiner 250 calculates the cumulative steering angle by measuring and accumulating the instantaneous steering angles at every determination period in the straight running state, and if the cumulative steering angles are equal to or greater than the predetermined steering threshold value, can do.

If steering wheel alignment is in a normal state, that is, if the neutral position of the steering apparatus and the neutral position of the wheel are synchronized, the steering angle should be kept at 0 in a state in which the vehicle runs straight.

Therefore, when the steering apparatus operates normally, that is, when the steering angle is in a normal state with an offset of 0, when the vehicle runs straight, the steer angle has a value other than 0 that the wheel alignment of the wheel is misaligned to some extent .

Therefore, the wheel alignment state determination unit 250 measures the instantaneous steering angle at every predetermined determination period during the period determined as the straight traveling of the vehicle by the linear travel state determination unit 240, and determines the wheel alignment state using the measured instantaneous steering angle can do.

If the wheel alignment is misaligned in one of the right and left directions, the instantaneous steering angle measured in the straight running state will always have a value of (+) or (-) and if the direction is misaligned in the other direction, (+) Value.

On the other hand, the wheel alignment state determiner 250 calculates the cumulative steering angle information by accumulating the instantaneous steering angle information measured for each determination period without determining the wheel alignment state only by the instantaneous instantaneous steering angle information at a certain point of time, It is possible to determine that the wheel alignment is in an abnormal state only when a certain threshold value (steering threshold value) is exceeded.

Even if the wheel alignment is in the normal state, the steer angle may be instantaneously changed due to the steering intention of the driver or the reverse input depending on the road state, although the vehicle is traveling straight ahead over a certain distance.

Therefore, it may be erroneous to determine the wheel alignment state only by the instantaneous steering angle information at a certain point of time. Accordingly, in the present invention, the instantaneous steering angle measured for each determination period is accumulated for more than a predetermined period to determine the wheel alignment state, It is possible to reduce judgment errors.

On the other hand, since the cumulative steering angle can have a value of (+) or (-) depending on the direction of misalignment of the wheel, the wheel alignment state determiner 250 may compare the absolute value of the cumulative steering angle with the steering threshold value desirable.

As shown in FIG. 2, the wheel alignment state sensing apparatus according to the present invention may further include an alarm unit 260 for outputting a warning signal when the wheel alignment state is determined to be abnormal.

The warning signal output by the warning unit may be output to the outside in the form of video, audio, vibration, or the like, and any form capable of recognizing the warning signal by the driver may be used.

In addition, the shape of the warning may be different depending on the degree of wheel alignment.

For example, the steering threshold value serving as a reference for determining the wheel alignment abnormality state may include a first threshold value and a second threshold value larger than the first threshold value, and the cumulative steering angle may be greater than or equal to the first threshold value, And outputs a second warning signal different from the first warning signal when the cumulative steering angle becomes equal to or greater than the second threshold value.

Of course, the warning method can be made in three or more stages rather than two stages.

Further, instead of considering only whether or not the cumulative steering angle reaches the steering threshold value, it is possible to use a warning method using the time information until reaching the steering threshold value, that is, May be set differently.

If the degree of misalignment of the wheel alignment is large, the cumulative steering angle will reach the steering threshold value even after a small number of determination period passes. In this case, the steering angle is more dangerous than when the steering threshold is reached , The level of warning is stronger.

In other words, when the steering threshold value is reached only in the first determination period of time based on the number of determination cycles until the cumulative steering angle reaches the steering threshold value using the same steering threshold value, And outputs the first warning signal, which is a warning signal at a lower level than the second warning signal, when the steering threshold value is reached only in the second determination period of times greater than the first determination period number.

As described above, in the embodiment of the present invention, by outputting the warning signal of 2 or more levels according to the degree of wheel alignment abnormality judged in the straight running state, the driver can be guided to recognize the misalignment degree of the wheel.

As described above, according to one embodiment of the present invention, the vehicle straight-running state is determined based on the curvature, the vehicle speed, and the yaw rate of the guard rail and the lane, The alignment state can be accurately determined.

Therefore, the driver recognizes the misalignment state of the wheel alignment in the course of running without a separate wheel alignment detection device, and copes with the misalignment state of the wheel alignment, thereby improving the risk of vehicle damage or accident due to wheel misalignment.

FIG. 3 shows an embodiment of the wheel alignment state sensing method according to FIG.

로 주행하고 있으며, 차량에 설치된 레이더 센서를 이용하여 가드레일(320)을 감지하는 것으로 가정한다.As shown in FIG. 3A, in the vehicle 310, the vehicle speed V,

And detects the guard rail 320 by using a radar sensor installed in the vehicle.

In this case, the radar sensor module receives / analyzes the reflection signal reflected from the guard rail, and detects the guard rail profile 320 'to which the point profile for the guard rail 320 is connected as shown in FIG. 3 (b) Can be generated.

In such a case, the radius of curvature R 'of the generated guardrail profile 320' can be calculated, which can be defined as the radius of curvature of the road or the radius of curvature of the road structure.

로부터 차량의 이동 경로가 이루는 곡률반경인 차량 경로 반경(R)을 산출하고 그 값을 임계 반경값과 비교함으로써 직진 주행 상태를 판정할 수 있다.On the other hand, the vehicle speed V, yaw rate

The vehicle running radius R, which is the radius of curvature formed by the moving path of the vehicle, is calculated, and the value is compared with the threshold radius value to determine the straight running state.

4 shows an overall configuration of a wheel alignment state sensing apparatus according to another embodiment of the present invention.

In the embodiment of Fig. 4, the map information of the navigation device installed in the vehicle is used without using a radar sensor or the like in order to recognize the radius of curvature of the road.

4 includes a navigation device 410 including a map DB and sensors such as a steering angle sensor 420, a yaw rate sensor 430 and a vehicle speed sensor, A straight traveling determining unit 440 for determining whether the vehicle is running straight ahead based on the road curvature, the vehicle speed and the yaw rate value confirmed from the map information of the map DB, And a wheel alignment state determiner 450 for determining an alignment state.

The navigation device 410 installed in the vehicle generally includes a GPS module and a map DB 412 capable of positioning the current position of the vehicle.

The map DB 412 stores map information, and curvature information of the road on which the vehicle is currently traveling is stored in the map information, or curvature information of the road can be calculated from at least road information.

Therefore, in the embodiment of FIG. 4, the curvature of the road is calculated from the map information of the navigation device 410 without using a separate sensor such as a radar or a camera.

4, the wheel alignment state determiner 450, and the warning unit 460 may have the same configuration as that of the embodiment of FIG. 2. In order to avoid redundancy, The description is omitted.

That is, the straight running determining unit 440 according to the embodiment of FIG. 4 determines the road curvature R 'of the road under the current driving by using the map information received from the navigation device, It is possible to judge whether or not the vehicle is traveling straight ahead by comparing the vehicle path radius R calculated from the speed and the yaw rate with the radius threshold value.

The wheel alignment state determination unit 450 determines the state of wheel alignment of the vehicle using the steering angle information measured in the straight running state. Specifically, the steering angle determination unit 450 measures the instantaneous steering angle at every determination period in the straight running state, The cumulative steering angle is calculated, and when the cumulative steering angle is equal to or greater than the steering threshold value, it is possible to determine the wheel alignment abnormality state.

The warning unit 460 may output two or more different warning signals depending on the degree of wheel alignment.

4 may further include a camera 414, and the straight-ahead running determining unit may determine that the distance between one of the lanes on both sides of the traveling road measured by the camera sensor and the distance between the vehicle and the vehicle Can be considered.

This will be described in more detail with reference to FIG. 5 below.

FIG. 5 shows an embodiment of the wheel alignment state sensing method according to FIG.

로 주행하고 있으며, 직진 주행 판단부(440)가 내비게이션장치의 맵정보로부터 산출되는 도로 곡률(R')과, 차속 및 요레이트로부터 산출되는 차량 경로 반경(R)을 기초로 차량의 직진 상태를 기본적으로 판정하는 것으로 가정한다.5, when the vehicle 510 is in a vehicle speed V,

And the straight running determination unit 440 determines the straight road state of the vehicle based on the road curvature R 'calculated from the map information of the navigation device and the vehicle path radius R calculated from the vehicle speed and the yaw rate It is assumed that the determination is basically made.

At this time, the distance between one of the lanes 520 and the vehicle is measured using the camera 414 installed on the vehicle 510.

The straight traveling state can be determined by further reflecting the condition that the distance change between the vehicle and the lane is a certain threshold value, that is, the distance threshold value or less.

5, the distance between the vehicle 510 and the lane 520 is measured at every determination period. As a result, the distance changes to d1, d2, and d3, and the change rate? D /? T Period) is less than or equal to the distance threshold value, the vehicle can be finally determined as a straight running state.

If the map information included in the navigation device is not accurate due to lack of updating, there may be an error in the road curvature calculated from the map information.

In this case, if the road is not a straight road but a curved road having a constant curvature, the yaw rate of the vehicle traveling along the curve may not change within a predetermined time. In this case, the vehicle path radius calculated from the vehicle speed and yaw rate And it can be erroneously judged as a straight running.

Further, even if the map information is accurate, it is natural that the vehicle has a constant steering angle when the vehicle does not travel along the center of the traveling lane.

Therefore, by further considering the rate of change of the distance between the vehicle and the lane as described above, it is possible to accurately determine whether the vehicle is traveling straight ahead, even when there is an error in the map information or when the vehicle is not traveling at the center.

In the above description, the curvature of a road structure (guardrail, lane, etc.) is detected using a radar or a camera (FIG. 2) and the curvature is detected using a navigation device (FIG. 4) , And in some cases, both methods may be applied.

For example, the curvature of a road structure (guardrail, lane, etc.) is sensed using a radar or a camera in contrast to the case where curvatures of roads (structures) are different from each other, The road curvature calculated using the navigation device can be used as a kind of verification.

In addition, it is also possible to use the curvatures of roads (structures) by two methods, and to use the average of two curvature values when the curvatures of roads (structures) according to the embodiments are different from each other.

6 shows an overall flow of a wheel alignment state sensing method according to an embodiment of the present invention.

)를 기초로 차량의 직진 주행여부를 판단하는 직진 주행 판단 단계(S630)와, 직진 주행인 상태에서 측정되는 조향각 정보를 이용하여 차량의 휠 얼라이먼트의 상태를 판정하는 휠 얼라이먼트 상태 판단 단계(S640)를 포함하려 구성될 수 있다.As shown in FIG. 6, the wheel alignment state sensing method according to the present invention detects a road structure in front of the vehicle using a structure sensor unit including a radar or a camera (S610), and determines a curvature of the road structure (S620), a curvature of a road structure, a vehicle speed (V) of a vehicle, and a yaw rate of a vehicle

A step S630 of determining a wheel alignment state of the vehicle based on the steering angle information measured in the straight running state S640, . ≪ / RTI >

FIG. 7 is a detailed flowchart of a straight running determination process according to the present invention, and FIG. 8 is a detailed flowchart of a wheel alignment state determination process.

As shown in FIG. 7, the straight-line driving determination step S630 is performed again on the basis of the curvature R 'of the road structure (guard rail, lane, median separator) detected by using the radar or the camera, (R ') is equal to or greater than a curvature threshold value (S632). If the curvature R'

When the curvature R 'of the road (structure) is equal to or greater than the curvature threshold, it is determined whether the vehicle speed of the vehicle at that time is not less than the critical vehicle speed and the yaw rate of the vehicle is less than or equal to the critical yaw rate (S634)

Of course, step S634 of comparing the vehicle speed and the yaw rate with the threshold value may be omitted in some cases.

)로부터 차량 경로 반경(R)을 산출한다.(S636)The vehicle speed V and the yaw rate of the vehicle (i.e.,

The vehicle path radius R is calculated from the vehicle path radius R (S636)

The calculated vehicle path radius R is compared with the threshold radius value, and if the vehicle path radius exceeds the threshold radius value, it is finally determined that the vehicle is running straight ahead (S638)

The wheel alignment state determination process (S640) as shown in FIG. 8 is performed only when it is determined that the vehicle is in the straight running state.

First, when it is determined that the vehicle is in the straight-ahead state, the steering angle outputted from the steering angle sensor at the initial determination time is measured as the instantaneous steering angle (S642)

Next, the determination period is incremented by one (S643), and the cumulative steering angle is updated by adding the measured instantaneous steering angle to the cumulative steering angle value (S644)

The updated cumulative steering angle value is compared with a second steering threshold value which is a larger value among the two steering threshold values in step S645. If the cumulative steering angle is equal to or greater than the second steering threshold value, the second warning signal is output using the warning unit. )

If the cumulative steering angle value is equal to or less than the second steering threshold value, the current steering angle value is compared with the first steering threshold value again (S647). If the cumulative steering angle value is equal to or greater than the first steering threshold value, )

If the cumulative steering angle value is smaller than the first steering threshold value, the process proceeds to the next determination period and repeats the above process.

As described above, by using the wheel alignment state detecting device according to the embodiment of the present invention, it is possible to recognize the curvature of the road structure such as a guard rail, a lane, or the road curvature by using a radar, a camera, or navigation map information, The vehicle straight-ahead running state can be determined based on the curvature, the vehicle speed, and the yaw rate value, and the wheel alignment state can be accurately determined using the cumulative cumulative steering angle during straight-ahead running.

Therefore, the driver recognizes the misalignment state of the wheel alignment in the course of running without a separate wheel alignment detection device, and copes with the misalignment state of the wheel alignment, thereby improving the risk of vehicle damage or accident due to wheel misalignment.

Further, by outputting a warning signal of two or more levels according to the degree of wheel alignment abnormality judged in the straight running state, the driver can recognize the misalignment degree of the wheel.

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. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them. 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. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (18)

A structure detection sensor installed inside or outside the vehicle to detect a road structure outside the vehicle;
A steering angle sensor for measuring a steering angle which is a rotation angle of the steering wheel;
A yaw rate sensor for measuring a yaw rate, which is a time variation of a yaw angle of the vehicle;
A straight running determining unit for determining a curvature of a road structure in front of the vehicle by receiving a signal from the structure detecting sensor unit and determining whether the vehicle is running straightly according to a curvature of the road structure, ;
A wheel alignment state determiner for determining a state of wheel alignment of the vehicle using steering angle information measured in a straight running state;
Wherein the wheel alignment state detecting device comprises: The method according to claim 1,
Wherein the structure detection sensor unit includes a radar, and the road structure is a guardrail sensed by the radar. The method according to claim 1,
Wherein the structure detection sensor unit includes a camera sensor, and the road structure is a guard rail or a driving lane sensed by the camera sensor. 3. The method of claim 2,
Wherein the straight run determination unit determines that the vehicle runs straight ahead only when the curvature of the road structure is not less than a critical curvature and the vehicle radius (Path Radius) calculated from the vehicle speed and the yaw rate is equal to or greater than a critical radius Wheel alignment state sensing device. 5. The method of claim 4,
Wherein the straight-ahead running determining unit determines that the vehicle runs straight-ahead only when the curvature of the road structure is not less than a critical curvature, the vehicle speed is not less than a critical vehicle speed, and the yaw rate is not more than a critical yaw rate. . 6. The method of claim 5,
Wherein the wheel alignment state determiner calculates a cumulative steering angle by measuring and accumulating an instantaneous steering angle at every determination period in a straight running state and determines the wheel alignment state to be a wheel alignment state if the cumulative steering angle is equal to or greater than a steering threshold value Sensing device. The method according to claim 6,
And a warning unit for outputting a warning signal when it is determined that the wheel alignment abnormality is detected. 8. The method of claim 7,
Wherein the steering threshold value includes a first threshold value and a second threshold value greater than the first threshold value and outputs a different warning signal according to a result of comparison between the cumulative steering angle and the first threshold value and the second threshold value And the wheel alignment state detection device. A navigation device installed in the vehicle and including map information;
A steering angle sensor for measuring a steering angle which is a rotation angle of the steering wheel;
A yaw rate sensor for measuring a yaw rate of the vehicle;
A straight travel determining unit for determining the road curvature of a road currently being operated using the map information received from the navigation device and determining whether the vehicle is traveling straight ahead in accordance with the road curvature, the vehicle traveling speed, and the yaw rate;
A wheel alignment state determiner for determining a state of wheel alignment of the vehicle using steering angle information measured in a straight running state;
Wherein the wheel alignment state detecting device comprises: 10. The method of claim 9,
Wherein the straight run determination unit determines that the vehicle runs straight ahead only when the curvature of the road structure is not less than a critical curvature and the vehicle radius (Path Radius) calculated from the vehicle speed and the yaw rate is equal to or greater than a critical radius Wheel alignment state sensing device. 11. The method of claim 10,
Further comprising a camera for detecting a lane ahead of the vehicle,
Wherein the straight-ahead driving determination unit determines that the vehicle is traveling straight-ahead only when the change in distance between one of the lanes on both sides of the driving road measured by the camera is less than a distance threshold value. 12. The method of claim 11,
Wherein the wheel alignment state determiner calculates a cumulative steering angle by measuring and accumulating an instantaneous steering angle at every determination period in a straight running state and determines the wheel alignment state to be a wheel alignment state if the cumulative steering angle is equal to or greater than a steering threshold value Sensing device. 13. The method of claim 12,
And a warning unit for outputting a warning signal when it is determined that the wheel alignment abnormality is detected. 14. The method of claim 13,
Wherein the steering threshold value includes a first threshold value and a second threshold value greater than the first threshold value and outputs a different warning signal according to a result of comparison between the cumulative steering angle and the first threshold value and the second threshold value And the wheel alignment state detection device. A curvature determination step of determining a curvature of a road structure in front of the vehicle using a structure sensor unit including a radar or a camera;
Determining whether the vehicle is running straight ahead based on a curvature of the road structure, a vehicle speed of the vehicle, and a yaw rate of the vehicle;
A wheel alignment state determination step of determining a state of wheel alignment of the vehicle using steering angle information measured in a straight running state;
And detecting the wheel alignment state. 16. The method of claim 15,
Further comprising a warning step of outputting a warning signal when it is determined that the wheel alignment abnormality is detected. 17. The method of claim 16,
The straight road running determination step determines that the vehicle runs straight ahead only when the curvature of the road structure is equal to or greater than the critical curvature and the vehicle radius (Path Radius) calculated from the vehicle speed and the yaw rate is equal to or greater than a critical radius Of the wheel alignment state. 18. The method of claim 17,
The wheel alignment state determination step may include:
Calculating a cumulative steering angle by measuring and accumulating instantaneous steering angles at every judging period in a straight running state;
And determining the wheel alignment abnormality state when the cumulative steering angle is equal to or greater than the steering threshold value.

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