KR20170136765A - Steering control apparatus and steering control method, and steering-state determination apparatus therefor - Google Patents

Abstract

The present invention relates to a steering control apparatus and a steering control method. Only measurement information such as a vehicle speed (), a steering angle (), and a yaw rate () of a vehicle and vehicle characteristic information of a wheelbase (L) between a front wheel and a rear wheel of the vehicle and a steering angle/front wheel rotation ratio (i) are used to easily determine five steering states of the vehicle including a neutral steering state, a simple understeer state, an understeer state with a slip, a simple oversteer state, and an unstable oversteer state and calculate a compensation current or compensation torque for abnormal steering state compensation to control the compensation current or the compensation torque to secure vehicle stability in an abnormal steering state.

Description

TECHNICAL FIELD [0001] The present invention relates to a steering control device, a steering control method, and a steering state determining device for the steering control device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a steering control apparatus and a steering state determining apparatus therefor, and more particularly to a steering control apparatus and a steering state determining apparatus, The present invention relates to a technique for checking the steering behavior state of a vehicle such as an understeer or an oversteer.

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.

On the other hand, when accelerating at the time of vehicle turning, a tendency to go outward beyond the target can be issued, which is commonly referred to as understeer.

This understeer phenomenon is a phenomenon in which the actual steering radius becomes larger than the front wheel steering angle, which occurs when the cornering force generated in the rear wheel is large, and although the collected vehicle basically has a weak understeer tendency, If the magnitude increases, it must be compensated through appropriate adjustment such as steering or braking.

Further, when the degree of understeer becomes severe, a slip phenomenon in which the wheel slips may occur, and this state can be expressed as a slip understeer state (Understeer with Slip). Such a slip-under-steer phenomenon can have a significant impact on vehicle stability, requiring immediate compensation or vehicle attitude control.

On the other hand, there is an oversteer which is a phenomenon that the vehicle body turns more than the steering angle as a concept opposite to understeer.

This over-steering phenomenon is caused by the turning of a constant radius and speed, but when the cornering force or revolute centripetal force generated at the front wheel suddenly accelerates, the moment of inertia of the inner front wheel becomes larger than that of the outer front and rear wheels. .

When this oversteer phenomenon occurs, the turning radius of the vehicle becomes smaller as the course of the vehicle becomes inward.

When the degree of oversteering is weak, it becomes a simple oversteer state that can return to a neutral steering state by a steering force or a braking force. However, if oversteering occurs over a certain degree, instability of the vehicle is diverted ) Is an unstable oversteer state (Unstable Oversteer).

Meanwhile, unlike the oversteer or understeer, the state in which the vehicle body is controlled in synchronization with the steering control of the vehicle can be expressed as a neutral steering state.

Thus, when the vehicle is turning, it can be placed in a normal neutral steering state or an abnormal steering state such as an over / understeer. In an abnormal steering state, specifically, a slip-under steering, a simple understeer, an oversteer, It is necessary to check the one and then perform the compensation control corresponding to the one.

In the conventional method, a reference yaw rate model in which the steering input of the driver and the running speed of the vehicle are input values is made, and the value obtained from the model is compared with the yaw rate value measured from the yaw rate sensor, The situation is judged.

In this conventional method, it is difficult to accurately determine the steering state according to the friction force of the road surface. Recently, efforts have been made to more accurately determine the vehicle condition using the vehicle slip angle information. However, The steering angle is not accurately measured because the steering angle is a value that can be obtained only through estimation.

Also, in order to accurately determine the steering state, the yaw angle, the yaw rate, the steering angle of the vehicle, or the slip of the wheel are detected. However, There is a disadvantage in that it is inconvenient for each state to be specifically identified because a separate measurement method is required.

In view of the foregoing, it is an object of the present invention to provide a steering control apparatus and method that can specifically confirm a steering state of a vehicle.

) 등으로부터 산출되는 특성 속도 제곱값(Characteristic Speed Square;

)의 부호와, 특성 속도값(

)과 현재 차속(ν)과의 관계 등을 기초로 차량의 비정상 조향 상태의 종류를 용이하게 확인할 수 있는 조향제어 장치 및 방법을 제공하는 것이다.
It is another object of the present invention to provide a vehicle having a vehicle speed v, a wheel base L and a steering angle? Between the front and rear wheels of the vehicle, and a yaw rate?

) And the like (Characteristic Speed Square;

), The sign of the characteristic speed value (

) And a current vehicle speed (?), And the like, and to provide a steering control apparatus and method that can easily confirm the type of an abnormal steering state of a vehicle.

) 등으로부터 산출되는 특성 속도 제곱값(Characteristic Speed Square;

)의 부호와, 특성 속도값(

)과 현재 차속(ν)과의 관계 등을 기초로 차량의 비정상 스티어링 상태의 종류를 용이하게 확인하고, 비정상 스티어링 상태 보상을 위한 보상토크 또는 보상전류를 산출하여 제어함으로써, 비정상 조향에 따른 조향 불안전성을 감소시키는 조향 제어 장치 및 방법을 제공하는 것이다.
It is another object of the present invention to provide a vehicle having a vehicle speed v, a wheel base L and a steering angle? Between the front and rear wheels of the vehicle, and a yaw rate?

) And the like (Characteristic Speed Square;

), The sign of the characteristic speed value (

) And the current vehicle speed (v), and by calculating and controlling the compensation torque or the compensation current for compensating for the abnormal steering state, the steering instability Of the steering angle of the steering wheel.

)의 측정정보와 상기 저장부로부터 독출된 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i)의 차량 특성 정보를 이용하여 차량의 현재 조향 상태를 판단하는 조향 상태 판단부와, 비정상 조향상태인 경우 그를 보상하기 위한 보상토크를 생성하여 조향제어부로 출력하는 보상부, 및 조향휠에 인가되는 인가 조향토크와 상기 보상토크를 이용하여 조향 보조 전류를 생성하여 조향모터를 제어하는 조향 제어부를 포함하는 조향 제어 장치를 제공한다.In order to achieve the above object, in one embodiment of the present invention, there is provided an information processing apparatus including a sensor unit including a vehicle speed sensor, a steering angle sensor and a yaw rate sensor, a storage unit for storing vehicle characteristic information, The vehicle speed?, The steering angle? And the yaw rate?

) Of the vehicle and the vehicle characteristics information of the wheel base (L) between the front and rear wheels of the vehicle and the rotation ratio (i) of the steering angle and the front wheel rotation angle read from the storage unit to determine the current steering state of the vehicle And a compensating unit configured to generate a steering assist current by using the applied steering torque applied to the steering wheel and the compensating torque to generate a steering assist current, And a steering control section for controlling the motor.

)의 측정정보와 상기 저장부로부터 독출된 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i)의 차량 특성 정보를 이용하여 차량의 현재 조향 상태를 판단하는 조향 상태 판단 단계와, 비정상 조향상태인 경우 그를 보상하기 위한 보상토크를 생성하여 조향제어부로 출력하는 보상 단계, 및 조향휠에 인가되는 인가 조향토크와 상기 보상토크를 이용하여 조향 보조 전류를 생성하여 조향모터를 제어하는 조향 제어 단계를 포함하는 조향 제어 방법을 제공한다.
According to another embodiment of the present invention, there is provided an information processing method including steps of: receiving measurement information from a sensor unit including a vehicle speed sensor, a steering angle sensor, and a yaw rate sensor; reading the vehicle characteristic information from a storage unit storing the vehicle characteristic information; (?), A steering angle (?) And a yaw rate (?) Of the vehicle received from the sensor unit.

) Of the vehicle and the vehicle characteristics information of the wheel base (L) between the front and rear wheels of the vehicle and the rotation ratio (i) of the steering angle and the front wheel rotation angle read from the storage unit to determine the current steering state of the vehicle And a control unit that generates a steering assist current by using the applied steering torque applied to the steering wheel and the compensating torque to generate a steering assist current, And a steering control step of controlling the motor.

) 등의 측정정보와, 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i) 등의 차량 특성정보만을 이용하여 차량의 조향 상태를 정확하게 확인할 수 있는 효과가 있다.According to the present invention as described below, the vehicle speed v, the steering angle? And the yaw rate?

) And the like, and the vehicle state information such as the wheelbase (L) between the front and rear wheels of the vehicle and the rotation ratio (i) of the steering angle and front wheel rotation angle can be accurately confirmed .

) 등의 측정정보와, 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i) 등의 차량 특성정보 등으로부터 산출되는 특성 속도 제곱값(Characteristic Speed Square;

)의 부호와, 특성 속도값(

)과 현재 차속(ν)과의 관계 등을 기초로 차량의 비정상 조향 상태의 종류를 용이하게 확인할 수 있는 효과가 있다.More specifically, the vehicle speed v, the steering angle? And the yaw rate?

) And the like, and vehicle characteristic information such as the wheelbase (L) between the front and rear wheels of the vehicle and the rotation ratio (i) of the steering angle and front wheel rotation angle.

), The sign of the characteristic speed value (

) And the current vehicle speed (v) and the like, it is possible to easily confirm the type of the abnormal steering state of the vehicle.

) 등의 측정정보와, 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i) 등의 차량 특성정보만을 이용하여 차량의 조향 상태를 정확하게 확인한 후, 비정상 조향 상태에 맞는 보상 제어를 할 수 있는 효과가 있다.
Furthermore, the vehicle speed v, the steering angle? And the yaw rate?

) And the like and the vehicle characteristic information such as the wheel base L between the front and rear wheels of the vehicle and the rotation ratio i of the steering angle and the front wheel rotation angle are precisely checked to determine the steered state of the vehicle, There is an advantageous effect that the compensation control can be performed in accordance with the above.

1 schematically shows a block diagram of a steering control device according to an embodiment of the present invention.
FIG. 2 is a graph showing five steering state regions determined using the steering control apparatus according to the present invention.
3 shows the overall flow of the steering control method according to the embodiment of the present invention.
FIG. 4 shows a detailed flow of the steering state determination step according to the present invention.
5 shows a configuration for generating a compensating torque and a final steering assist current for compensating the abnormality when judged to be an abnormal steering condition.

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 schematically shows a block diagram of a steering control device according to an embodiment of the present invention.

) 등의 측정정보와, 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i) 등의 차량 특성정보를 이용하여 차량의 조향 상태, 즉 정상적인 중립 조향(Neutral Steer), 비정상 조향상태인 언더스티어(Understeer) 또는 오버스티어(Oversteer) 상태를 판단하는 기능을 한다.The steering control apparatus according to the embodiment of the present invention calculates the steering angle?, The steering angle? And the yaw rate? Of the vehicle.

) And the like, and the vehicle characteristics information such as the wheel base L between the front and rear wheels of the vehicle and the rotation ratio i of the steering angle and the front wheel rotation angle, ) And an understeer state or an oversteer state, which is an abnormal steering state.

Of course, the steering control device according to the present invention may further include a compensating function for controlling the magnitude of the auxiliary current applied to the steering motor when the steered state is an abnormal steering state, .

1, the steering control apparatus according to the present invention includes a sensor unit 110 including a vehicle speed sensor, a steering angle sensor, and a yaw rate sensor, a storage unit 120 storing vehicle characteristic information, And a steering state determination unit (130) for determining a current steering state of the vehicle based on the measurement information received from the vehicle and the vehicle characteristics information stored in the storage unit.

Further, when it is determined by the steering state determination unit 130 that the current steering state is the understeer with slip state, the compensation torque value for compensating the state or the compensation current value corresponding to the compensation torque value A steering torque applied to the steering wheel and a compensating torque value or a compensating current value transmitted from the compensating unit to generate a steering assist current to control the steering motor And may further include a steering control unit 150.

)를 측정하는 요레이트 센서(116)를 포함한다.The sensor unit 110 includes a vehicle speed sensor 112 for outputting the current speed of the vehicle, a steering angle sensor 114 for measuring the rotational angle of the steering shaft connected to the steering wheel or the steering wheel, The yaw rate (Yaw Rate;

And a yaw rate sensor 116 for measuring the yaw rate.

) 등의 측정정보를 센싱하여 조향 상태 판단부(130)로 전송한다.The sensor unit 110 periodically determines the vehicle speed v, the steering angle? And the yaw rate? Of the vehicle when the steering state determination unit 140 requests the vehicle steering state measurement.

And transmits the sensed information to the steering state determination unit 130. The steering state determination unit 130 determines the steering angle based on the measured information.

The storage unit 120 is a storage unit such as an EEPROM included in the steering control ECU or the like. The storage unit 120 stores vehicle characteristics information such as the wheel base L between the front and rear wheels of the vehicle and the rotation ratio i of the steering angle and front wheel rotation angle, Is stored.

The wheel base L between the vehicle front wheel and the rear wheel is a value determined for each vehicle as a distance between the front wheel and the rear wheel and is not necessarily limited to the term wheel base L between the vehicle front wheel and the rear wheel, Distance, axle distance, and so forth.

The rotation ratio i of the steering angle and the front wheel rotation angle is a ratio between the steering angle of the steering wheel, that is, the steering angle and the corresponding front wheel rotation angle, and may be expressed as a gear ratio have.

) 또는 특성 속도값(

)을 산출하는데 사용된다.
The information of the wheel base L and the steering angle / front wheel rotation ratio (i) between the front and rear wheels of the vehicle is stored in advance in the storage unit at the time of vehicle manufacture or at the time of designing the steering system. Characteristic Speed Square;

) Or characteristic speed value (

). ≪ / RTI >

) 등의 측정정보와 저장부(120)에서 독출한 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각/전륜 회전비율(i)의 차량 특성정보를 이용하여 특성 속도 제곱값(Characteristic Speed Square;

)을 산출하고, 그 특성 속도 제곱값(Characteristic Speed Square;

)의 부호(양 또는 음)와, 특성 속도값(

)과 현재 차속(v)과의 대소관계 및 임계 속도값(

)과 현재차속(v)과의 대소관계에 따라서 차량의 비정상 조향 상태를 판단하는 기능을 한다.Steering state determination unit 130 determines the steering angle?, The steering angle?, And the yaw rate? Of the vehicle provided from the sensor unit 110,

And the vehicle characteristic information of the wheel base L and the steering angle / front wheel rotation ratio i between the front and rear wheels of the vehicle read out from the storage unit 120,

), And calculates the characteristic speed square (Characteristic Speed Square;

(Positive or negative) and the characteristic speed value (

) And the present vehicle speed (v) and the critical speed value (

) And the present vehicle speed v in accordance with the magnitude relationship between the vehicle speed V and the present vehicle speed v.

)을 산출하는 구성과, 산출된 특성 속도 제곱값(Characteristic Speed Square;

)을 이용하여 차량의 비정상 조향상태, 즉 단순 언더스티어(Understeer), 슬립있는 언더스티어(Understeer with slip), 단순 오버스티어(Oversteer), 불안정 오버스티어(Unstable Oversteer)를 판단하는 구성에 대하여 설명한다.Hereinafter, the characteristic speed square value (hereinafter referred to as " characteristic speed square value "

), And a configuration for calculating the calculated characteristic speed square value (?

A simple understeer, a slip understeer, a simple oversteer, and an unstable oversteer will be described with reference to FIG. 1 .

)은 아래 수학식 1에 의하여 결정될 수 있다.
First, the characteristic speed square (Characteristic Speed Square;

) Can be determined by the following equation (1).

[Equation 1]

는 요레이트값으로서, 센서부에서 측정되는 측정정보이고, i는 조향각에 대한 전륜 회전각도 비율인 조향각/전륜 회전비율, L은 전륜-후륜 사이의 휠베이스값으로서 차량마다 정해지는 차량 특성 정보이다.In Equation (1), v (t) is the current vehicle speed, δ (t) is the steering angle,

I is the steering angle / front wheel rotation ratio, which is the front wheel rotation angle ratio to the steering angle, and L is the vehicle characteristic information, which is determined for each vehicle as the wheelbase value between the front and rear wheels .

)은 특정한 조향각(δ)에서 차속(v)을 증가시킬 때 전륜 슬립 발생이 시작되는 시점의 속도의 제곱값을 의미한다.The characteristic speed square value < RTI ID = 0.0 > (I) < / RTI >

Denotes a square value of the speed at which the front wheel slip is started when the vehicle speed v is increased at a specific steering angle delta.

)은 특정한 조향각(δ)에서 차속(v)을 증가시킬 때 전륜 횡력이 한계점에 도달하는 시점의 속도의 제곱값을 의미한다.In other words, the Characteristic Speed Square

Denotes a square value of the speed at which the front wheel lateral force reaches the limit point when the vehicle speed v is increased at a specific steering angle delta.

)의 물리적인 의미는 특성 속도 제곱값(

)이 양(+)의 값을 가지는 경우에 유효하며, 그 때의 조향상태는 언더스티어 상태를 나타낸다.On the other hand, the characteristic speed square value

) Means the characteristic velocity square value (

) Has a positive value, and the steering state at that time is an understeer state.

)이 음(-)의 값인 경우에는 오버스티어 상태임을 나타내며, 그 때의 특성속도 제곱값(

)의 절대값을 기초로 임계 속도값(

)이 결정될 수 있다.Further, the characteristic velocity square value (

) Is negative (-), it indicates that it is an over-steering state, and the characteristic speed square value

) On the basis of the absolute value of the threshold velocity value

) Can be determined.

)은 차속이 증가함에 따라 차량 불안정성이 발산(Diverse)하기 시작하는 시점의 차속을 의미하며, 단순 오버스티어 상태와 불안정 오버스티어(Oversteer Unstable) 상태를 구분하는 경계속도의 의미를 가진다. The critical velocity value (

Means the vehicle speed at which the vehicle instability begins to diverge as the vehicle speed increases, and has a boundary speed that distinguishes between a simple oversteer state and an unstable oversteer state.

)은 아래와 같은 수학식 2를 기초로 산출될 수 있다.
In other words, a critical velocity value ("

) Can be calculated based on the following Equation (2).

&Quot; (2) "

) 등의 측정정보와 저장부(120)에서 독출한 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각/전륜 회전비율(i)의 차량 특성정보를 이용하여 산출한

의 값이 1보다 큰 경우에는 언더스티어 상태가 되며, 이 때에는 수학식 1에 의하여 산출되는 특성 속도 제곱값(

)만을 조향 상태 판단에 이용하며,

의 값이 1보다 작은 경우에는 오버스티어 상태가 되며 이 때에는 수학식 2에 의하여 산출되는 임계 속도 제곱값(

)이용하여 조향상태를 판단한다.That is, the vehicle speed v, the steering angle? And the yaw rate?

) And the vehicle characteristic information of the wheel base L and the steering angle / front wheel rotation ratio (i) between the vehicle front-rear wheel read from the storage unit 120

When the value of the characteristic velocity value is greater than 1, the understeer state is obtained. In this case, the characteristic velocity value (

) Is used for steering state determination,

Is in the oversteer state. In this case, the value of the critical speed square value < RTI ID = 0.0 >

) To determine the steering state.

)의 부호가 양(+)인 경우에는 언더스티어 상태로 판단하고, 다시 현재 차속(v)과 특성속도값(

)을 비교하여 현재 차속(v)이 특성속도값(

) 이상인 경우에는 슬립있는 언더스티어(Understeer with slip) 상태로, 현재 차속(v)이 특성속도값(

)보가 작은 경우에는 단순 언더스티어 또는 슬립없는 언더스티어(Understeer without slip) 상태로 판단한다.More specifically, the steering state determination unit 130 determines the steering angle?

) Is positive (+), it is determined that the vehicle is in the understeer state, and the current vehicle speed v and the characteristic speed value

) To compare the present vehicle speed v with the characteristic speed value (

), The present vehicle speed v is changed to the characteristic speed value (V) by the understeer with slip state,

) If the beam is small, it is judged to be a simple understeer or understeer without slip.

)의 부호가 음(-)이거나, 수학식 2에 의하여 산출되는 임계 속도 제곱값(

)이 양(+)의 값인 경우에는 오버스티어 상태로 판단하고, 다시 현재 차속(v)과 임계속도값(

)을 비교하여 현재 차속(v)이 임계속도값(

) 이상인 경우에는 불안정한 오버스티어(Oversteer Unstable) 상태로, 현재 차속(v)이 임계속도값(

)보다 작은인 경우에는 단순 오버스티어 상태로 판단한다.In addition, the steering state determination unit 130 determines the steering state of the steering wheel based on the characteristic speed square value (

) Is negative (-), or the critical velocity square value (

) Is a positive value, it is determined to be in the oversteer state, and the current vehicle speed v and the critical speed value (

) To compare the present vehicle speed v with the threshold speed value (

), It is determined that the present vehicle speed v is in an unstable oversteer state,

), It is determined to be a simple oversteer state.

On the other hand, when the present vehicle speed v is equal to or less than the threshold vehicle speed v0, the steering state determiner 130 may determine that the vehicle is in a neutral steer state.

The steered state determination unit 130 determines whether or not the current vehicle speed v is equal to or greater than the threshold vehicle speed v0 and the yaw rate gain error? Defined by Equation (3) It is possible to determine that the vehicle is in the neutral steering state.

&Quot; (3) "

)의 절대값이 일정한 임계값 이하인 경우에도 중립 조향상태로 판단할 수도 있다.The steering state determination unit 130 determines whether the current vehicle speed v is equal to or greater than the threshold vehicle speed v0 by using the characteristic speed square value

) Is less than or equal to a predetermined threshold value, it can be determined as a neutral steering state.

으로 정의되는 요레이트 게인(Yaw Rate Gain)을 기준으로 전술한 특성속도값(

) 및 임계속도값(

)을 정의하면, 특성속도(

)는 언더스티어시 최대 요레이트 게인을 가지는 차량의 속도를 의미하며, 임계속도(

)는 오버스티어시 요레이트 게인이 무한대가 되는 차속을 의미한다.Meanwhile,

(Yaw Rate Gain) defined by the above-described characteristic velocity value

) And the critical velocity value (

), The characteristic speed (

) Denotes the speed of the vehicle having the maximum yaw rate gain under the understeer, and the critical speed

) Means a vehicle speed at which the yaw rate gain at the time of oversteering becomes infinite.

)이 0인 경우에는 중립 조향상태가 되며, 0보다 큰 경우에는 언더스티어 상태가 되고, 0보다 작은 경우에는 오버스티어 상태가 된다.That is, the characteristic speed square value (

) Is 0, the steering is in the neutral state. When the steering angle is larger than 0, the steering wheel is in the understeer state. When the steering angle is smaller than 0, the steering wheel is in the oversteer state.

) 등의 측정정보와, 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각/전륜 회전비율(i)의 차량 특성정보만을 이용하여 특성 속도 제곱값(Characteristic Speed Square;

)을 산출하고, 그 특성 속도 제곱값(Characteristic Speed Square;

)의 부호(양 또는 음)와, 특성 속도제곱값(

)으로부터 도출되는 특성속도값(

) 또는 임계속도값(

)과 현재 차속(v)의 대소관계에 따라서 차량의 조향 상태, 즉 중립조향상태, 단순 언더스티어 상태, 술립있는 언더스티어 상태, 단순 오버스티어 상태, 불안정 오버스티어 상태의 5가지 조향 상태를 용이하게 판단할 수 있는 효과가 있다.As described above, the steering control device according to the present invention is capable of controlling the vehicle speed v, the steering angle? And the yaw rate?

) And the like, and vehicle characteristic information of the wheel base L and the steering angle / front wheel rotation ratio i between the vehicle front-rear wheel and the rear wheel.

), And calculates the characteristic speed square (Characteristic Speed Square;

(Positive or negative) and the characteristic velocity square value (

) ≪ / RTI >

) Or threshold velocity value (

The steering state of the vehicle, that is, the neutral steering state, the simple understeer state, the understeer state, the simple oversteer state, and the unstable oversteer state, depending on the magnitude of the present vehicle speed v There is an effect that can be judged.

Also, as will be described later, when the current steering state of the vehicle is in a state requiring compensation through control of the steering system, specifically, in a slip-under-steer state or an unstable oversteer state, the EPS steering system appropriately performs steering- It is necessary to maintain the stability of the vehicle.

To this end, the steering control apparatus of the present invention includes a compensator 140 for generating a compensating torque for compensating for an unsteady steering state and outputting the compensation torque to the steering control unit, and a control unit 140 for using the compensating torque And a steering control unit 150 for generating a steering assist current to control the steering motor.

The compensating unit 140 generates a compensating torque for compensating for an abnormal steering state after the steered state of the vehicle is confirmed by the steering state determining unit 130, and the compensating torque can be determined according to the yaw rate gain error.

), 차량 전륜-후륜 사이의 휠베이스(L)로부터 산출되는 요레이트 게인 에러값에 비례하도록 결정될 수 있으며, 이 때의 요레이트 게인 에러값은 전술한 수학식 3에 의하여 정의된다.
That is, the compensating torque output from the compensating unit 140 is a vehicle speed v, a steering angle? And a yaw rate?

) And the yaw rate gain error value calculated from the wheel base L between the vehicle front wheel and the rear wheel, and the yaw rate gain error value at this time is defined by Equation (3).

In the case where the steering state is an understeer state in which the steering state is slip, the steering control unit 150 controls to decrease the applied steering torque by the compensating torque, and when the steering state is the unstable oversteer, Can be controlled.

5 shows a configuration for generating a compensating torque and a final steering assist current for compensating the abnormality when judged to be an abnormal steering condition.

5, the compensating torque has a proportional relationship with respect to the yaw rate gain error, and the compensating unit 140 of the present invention sets the compensating torque to 0 when the yaw rate gain error is equal to or less than a, It can be expressed as a zone (Dead Zone).

Further, when the yaw rate gain error is between a and b (b > a), the compensation unit 140 determines the compensation torque as a value proportional to the yaw rate gain error value, and this interval can be represented as a proportional region .

Of course, in the proportional region, as shown in FIG. 5, the compensating torque may be linearly proportional to the yaw rate gain error value, but the present invention is not limited thereto. It is also possible to have another proportional relation (second proportional function, logarithmic function proportional function, etc.) There will be.

In addition, when the yaw rate gain error is equal to or greater than b, the compensating unit 130 determines the compensating torque as a constant first upper limit value, and this interval can be expressed as a saturation zone.

When the understeer state of the slip is confirmed as a result of the determination by the steering state determination unit 130, the compensation unit 140 calculates a compensation torque according to the yaw rate gain error, and then, So that the assist current is reduced and the steering feeling is heavy.

That is, when the slip occurs, the auxiliary steering force is reduced to stably maintain the overall behavior of the vehicle.

On the other hand, the steering control unit 150 calculates the final control torque using the compensation torque value transmitted from the compensation unit and the applied steering torque value measured from the torque sensor according to the steering wheel rotation, and applies the final control torque to the steering motor Generates a steering assist current.

At this time, the compensation torque can be determined by the compensation torque calculated by the yaw rate gain error. If the value is negative, the compensation torque is transmitted to the steering control unit 150, Can be added to the torque value.

Further, when the compensation torque is calculated as a positive value, the steering control unit 150 determines the final torque by subtracting the final compensation torque from the applied steering torque value according to the steering wheel rotation, and generates the steering assist current accordingly do.

5 (b) shows the steering current map for generating the steering assist current by using the applied steering torque value and the compensating torque value by the steering control section 150 of the present invention.

As shown in the figure, the applied steering torque T1 is generated in accordance with the steering wheel rotation of the driver. If the present invention is not applied, the steering assist current I1 corresponding to the applied steering torque T1 in the current curve is generated, Lt; / RTI >

However, when the present invention is applied, the final torque T2 is determined by subtracting the compensating torque T 'from the applied steering torque T1, and the steering assist current I2 corresponding to the final torque is applied to the steering motor .

As described above, when the present invention is applied, in the case of a slip understeer, by applying a steering assist current as small as a compensating torque determined according to a yaw rate gain error and a vehicle speed, the steering feeling is heavily weighted to prevent excessive steering in the understeer state will be.

Further, although not shown, the steering control section of the present invention may control not only the control in the slip-under-steered state but also the compensation torque in the case of an unstable oversteer state to add to the applied steering torque.

In the case of an unstable oversteer, the driver performs a counter-steer operation in which the driver steers in the opposite direction of the steering. That is, steering in the opposite direction of the steering direction.

At this time, the compensation steering torque is added to the applied steering torque to be controlled in the return steering or countersteering operation so as to be quickly brought to the steering neutral state.

That is, when the driver is determined to be in an unstable oversteer state and the current driver performs the return steering or countersteering operation, the steering control unit 150 adds the compensating torque calculated by the compensating unit 140 to the applied steering torque, Generating an auxiliary current.

In this unstable oversteer state, the compensating torque value generated by the compensating unit 140 may also be calculated as a value proportional to the yaw rate gain error value defined by Equation (3).

 FIG. 2 is a graph showing five steering state regions determined using the steering control apparatus according to the present invention.

In FIG. 2, the abscissa indicates the vehicle speed (v) and the ordinate indicates the yaw rate gain defined in Equation (3), and the slope of the reference line 210 as a reference of the steady state is 1 / L. Here, L is the wheel base L between the front and rear wheels of the vehicle.

As shown in FIG. 2, when the yaw rate gain with respect to the vehicle speed is within a predetermined range from the reference line (that is, the normal region 220), it is determined as a neutral steering state or a neutral state.

Meanwhile, the neutral steering state may be divided into a first steady region 222 whose vehicle speed is equal to or lower than a predetermined critical vehicle speed and a second steady region 224 whose vehicle speed is not lower than a critical vehicle speed. And the vehicle speed is equal to or less than the critical vehicle speed among the conditions in which the state determining unit determines that the vehicle is in the neutral steering state.

On the other hand, the second steady-state region 224 is a state in which the vehicle speed is equal to or higher than the critical vehicle speed and the yaw rate error value defined by Equation (3) is equal to or less than the threshold error value .

)의 부호가 음(-)이 되고, 반대로 수학식 2로 정의되는 임계 속도 제곱값(

)이 양의 값이 된다.When the yaw rate gain value with respect to the vehicle speed is above the normal region 220, the oversteer state is established. In this state, the characteristic speed square value (

) Is negative (-), and conversely, the sign of the critical velocity square value (

) Is a positive value.

)을 기준으로, 현재 차속(v)이 임계속도값(

) 이상인 영역이 불안정한 오버스티어(Oversteer Unstable) 상태 영역(244)로, 현재 차속(v)이 임계속도값(

)보다 작은 영역이 단순 오버스티어 영역(242)으로 정의된다.At this time, the critical velocity value (

), The current vehicle speed v is calculated as the critical speed value (

(Oversteer Unstable) state region 244 in which the current vehicle speed v is equal to or less than the threshold speed value

) Is defined as a simple oversteer area 242. [0050]

)의 부호가 양(+)이 되고 그로부터 산출되는 특성속도값(

)이 정의된다.Further, when the yaw rate gain value relative to the vehicle speed is below the normal region 220, the understeer state is obtained. In this state, the characteristic speed square value (

) Becomes positive (+) and the characteristic speed value (

) Is defined.

)을 기준으로, 현재 차속(v)이 특성속도값(

) 이상인 영역이 슬립있는 언더스티어(Understeer with slip) 상태 영역(234)로, 현재 차속(v)이 특성속도값(

)보다 작은 영역이 단순 언더스티어 영역(232)으로 정의된다.Characteristic speed value (

), The current vehicle speed v is the characteristic speed value

Of the vehicle speed V is in the understeer with slip state area 234 where the current vehicle speed v is the characteristic speed value

) Is defined as a simple under-steer region 232. In this case,

) 또는 임계속도값(

)을 결정하고, 현재 차속(v)을 그와 비교함으로써 차량의 조향상태를 판단할 수 있다.As described above, according to the present invention, by using only the yaw rate, the steering angle, the vehicle speed, the wheel base between the front and rear wheels, and the steering angle /

) Or threshold velocity value (

) And determine the steering state of the vehicle by comparing the current vehicle speed v with the current vehicle speed v.

Accordingly, it is possible to easily determine the steering state of the vehicle as compared with the existing technology in which a separate sensor is required to determine an abnormal steering state, such as a slip-understeer or an unstable oversteer.

FIG. 3 shows an overall flow of a steering control method according to an embodiment of the present invention, and FIG. 4 shows a detailed flow of a steering state determination step according to the present invention.

)의 측정정보와 상기 저장부로부터 독출된 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i)의 차량 특성 정보를 이용하여 차량의 현재 조향 상태를 판단하는 조향 상태 판단 단계(S330)를 포함할 수 있다.3, the steering control method according to the embodiment of the present invention includes a measurement information reception step (S310) of receiving measurement information from a sensor unit including a vehicle speed sensor, a steering angle sensor and a yaw rate sensor, A vehicle characteristic information extracting step (S320) for reading vehicle characteristics information from a storage unit storing information, a vehicle speed (?), A steering angle (?) And a yaw rate (?

) Of the vehicle and the vehicle characteristics information of the wheel base (L) between the front and rear wheels of the vehicle and the rotation ratio (i) of the steering angle and the front wheel rotation angle read from the storage unit to determine the current steering state of the vehicle And a state determination step S330.

In addition, when a steady state is determined to be an unsteady steering state as a result of the steering state determination, a compensation step (S340) for generating and outputting a compensation torque for compensating the steering torque is performed. And a steering control step (S350) of generating a steering assist current to control the steering motor.

The detailed flow of the steering state confirmation step (S330) will be described in more detail below with reference to FIG.

The steering state determination unit 130 compares the current vehicle speed received from the sensor with the vehicle speed threshold value v0 to determine whether the current vehicle speed v is smaller than the vehicle speed threshold value or whether the calculated yaw rate gain error? If it is smaller than the value (? 0), it is determined that the vehicle is in the neutral steering state and the process is terminated (S450).

)의 측정정보와 상기 저장부로부터 독출된 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각과 전륜 회전각의 회전비율(i)의 차량 특성 정보를 이용하여 수학식 1로부터 특성 속도 제곱값(Characteristic Speed Square;

)을 산출한다. (S415)On the other hand, when the current vehicle speed exceeds the vehicle speed threshold value and the yaw rate gain error is larger than the threshold error value, the vehicle speed v, the steering angle? And the yaw rate?

And the vehicle characteristic information of the wheel base L between the front and rear wheels of the vehicle and the rotation ratio (i) of the steering angle and the front wheel rotation angle read from the storage unit, Characteristic Speed Square;

). (S415)

)의 절대값이 임계값보다 큰지 확인(S420)한 후, 특성 속도 제곱값(Characteristic Speed Square;

)의 절대값이 임계값 이하인 경우에는 중립 조향상태로 판단한 후 종료한다(S450). 물론, 이러한 중립 조향 판단과정은 경우에 따라서 생략될 수 있다.Next, the calculated characteristic speed square value

) Is greater than a threshold value (S420), and then a characteristic speed square value is calculated.

) Is less than or equal to the threshold value, it is determined that the vehicle is in the neutral steering state and the process is terminated (S450). Of course, such a neutral steering determination process may be omitted in some cases.

)의 부호를 확인하여(S425), 특성 속도 제곱값(

)이 양의 값을 가지는 경우에는 언더스티어 상태를 가정하고, 특성 속도 제곱값(

)의 제곱근인 특성 속도값(

)으로 결정하고, 현재 차속(v)과 특성 속도값(

)을 비교한다.(S430)The calculated characteristic velocity square value (

(S425), and the characteristic speed square value (

) Has a positive value, the understeer state is assumed, and the characteristic speed square value (

) ≪ / RTI >

) And determines the current vehicle speed v and the characteristic speed value

) (S430)

)보다 큰 경우에는 슬립있는 언더스티어 상태로 판단(S434)하고, 현재 차속(v)이 특성 속도값(

)보다 작은 경우에는 단순 언더스티어 상태로 판단한다.(S432)As a result of comparison, if the current vehicle speed v is less than the characteristic speed value

(S434), the current vehicle speed v is determined as the characteristic speed value ("

), It is determined to be a simple under-steering state (S432)

)이 음의 값을 가지는 경우에는 오버스티어 상태를 가정하고, 특성 속도 제곱값(

)의 절대값의 제곱근을 임계속도값(

)으로 결정하고, 현재 차속(v)과 임계속도값(

)을 비교한다.(S440)On the other hand, in step S425, the characteristic speed square value (

) Has a negative value, the oversteer state is assumed, and the characteristic speed square value (

) Is the critical velocity value (

), And determines the current vehicle speed v and the critical speed value (

) (S440)

)보다 큰 경우에는 불안정한 오버스티어 상태로 판단하고(S444), 현재 차속(v)이 임계속도값(

)보다 작은 경우에는 단순 오버스티어 상태로 판단한다.(S442)As a result of comparison, if the current vehicle speed v is less than the threshold speed value

(S444). If the current vehicle speed v is less than the threshold speed value < RTI ID = 0.0 >

), It is determined to be a simple oversteer state (S442)

On the other hand, when it is determined that the current steering state is an abnormal steering state requiring steering control, that is, a sleeping understeer state or an unstable oversteer state, a compensation torque proportional to a yaw rate gain error defined by Equation 3 is calculated And then applies it to the steering control unit.

The steering control unit controls the steering motor by adding or subtracting the compensating torque to the applied steering torque applied to the steering wheel by the driver to determine the final torque and generating the steering assist current accordingly.

More specifically, in the steering control step, when the steering state is an understeer in which the steering is slip, it is controlled to decrease by the compensating torque at the applied steering torque, and when the steering state is the unstable oversteer, .

) 등의 측정정보와, 차량 전륜-후륜 사이의 휠베이스(L) 및 조향각/전륜 회전비율(i)의 차량 특성정보만을 이용하여 차량의 조향 상태, 즉 중립조향상태, 단순 언더스티어 상태, 술립있는 언더스티어 상태, 단순 오버스티어 상태, 불안정 오버스티어 상태의 5가지 조향 상태를 용이하게 판단할 수 있는 효과가 있다.As described above, according to the present invention, the vehicle speed v, the steering angle? And the yaw rate?

The steering angle of the vehicle, the neutral steering state, the simple understeer state, the braking state, and the like, using only the vehicle characteristic information of the wheel base L and the steering angle / front wheel rotation ratio i between the vehicle front- There is an effect that it is possible to easily determine five steering states, i.e., an understeer state, a simple oversteer state, and an unstable oversteer state.

)을 산출하고, 그 특성 속도 제곱값(Characteristic Speed Square;

)의 부호(양 또는 음)와, 특성 속도제곱값(

)으로부터 도출되는 특성속도값(

) 또는 임계속도값(

)과 현재 차속(v)의 대소관계에 따라서 차량의 조향 상태를 용이하게 판단할 수 있는 효과가 있다.More specifically, by using only the measurement information and the vehicle characteristic information described above, the characteristic speed square value

), And calculates the characteristic speed square (Characteristic Speed Square;

(Positive or negative) and the characteristic velocity square value (

) ≪ / RTI >

) Or threshold velocity value (

And the current vehicle speed v, it is possible to easily determine the steering state of the vehicle.

Further, when it is determined that the vehicle is in an abnormal steering state, a compensating torque is generated and steering control is performed on the basis of the compensation torque, thereby enabling the EPS steering system to appropriately perform the steering torque feedback compensation in the slip-under- The stability can be maintained.

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 (20)

A sensor unit including a vehicle speed sensor, a steering angle sensor and a yaw rate sensor;
A storage unit for storing vehicle characteristic information;
A steering angle and a yaw rate of the vehicle received from the sensor unit, and vehicle characteristics information of a wheelbase between the front and rear wheels of the vehicle and a rotation ratio of the front wheel rotational angle read from the storage unit A steering state determining unit for determining a current steering state of the vehicle by using the steering state determining unit;
A compensation unit for generating a compensation torque to compensate for the abnormal steering state and outputting the compensation torque to the steering control unit;
A steering control unit for generating a steering assist current by using the applied steering torque applied to the steering wheel and the compensating torque to control the steering motor;
And a steering angle of the steering wheel. The method according to claim 1,
The steering state determination unit determines the steering angle and the yaw rate based on the measured information of the vehicle speed, the steering angle and the yaw rate, and the characteristic information of the wheelbase and the steering angle / (Positive or negative) of the characteristic speed square and the characteristic speed value or critical speed value derived from the characteristic speed square value and the current vehicle speed, And determines one of the steering angles. 3. The method of claim 2,
The steering state determination unit determines the square root of the characteristic speed square value as the characteristic speed value when the characteristic speed square is a positive value, and determines the slip-state understeer state when the current vehicle speed is greater than the characteristic speed value And when the current vehicle speed is smaller than the characteristic speed value, it is determined to be a simple understeer state. 3. The method of claim 2,
Wherein the steering state determiner determines a square root of an absolute value of a characteristic speed square value as a critical speed value when the characteristic speed square is a negative value and when the current vehicle speed is greater than a critical speed value, Steering state when the current vehicle speed is smaller than the threshold speed value. The method according to claim 1,
Wherein the steering state determination unit determines that the vehicle is in the neutral steering state when the current vehicle speed is equal to or less than the critical vehicle speed. The method according to claim 1,
Wherein the steering state determining unit determines that the vehicle is in the neutral steering state when the vehicle speed, the steering angle, the yaw rate, and the yaw rate gain error calculated from the wheel base between the front and rear wheels of the vehicle are equal to or less than the threshold error value. . The method according to claim 1,
Wherein the compensation torque output from the compensation unit is determined to be proportional to a vehicle speed, a steering angle and a yaw rate, and a yaw rate gain error value calculated from a wheel base between the front and rear wheels of the vehicle. 8. The method of claim 7,
The steering control unit may be controlled so as to decrease by the compensating torque at the applied steering torque when the steering state is an understeer with slip and to control so that the compensating torque is added to the applied steering torque when the steering state is an unstable oversteer The steering control device comprising: A sensor unit including a vehicle speed sensor, a steering angle sensor and a yaw rate sensor;
A storage unit for storing vehicle characteristic information;
A steering angle and a yaw rate of the vehicle received from the sensor unit, and vehicle characteristics information of a wheelbase between the front and rear wheels of the vehicle and a rotation ratio of the front wheel rotational angle read from the storage unit A steering state determining unit for determining a current steering state of the vehicle by using the steering state determining unit;
And a steering angle sensor for detecting steering angle of the steering wheel. 10. The method of claim 9,
The steering state determination unit determines the steering angle and the yaw rate based on the measured information of the vehicle speed, the steering angle and the yaw rate, and the characteristic information of the wheelbase and the steering angle / (Positive or negative) of the characteristic speed square and the characteristic speed value or critical speed value derived from the characteristic speed square value and the current vehicle speed, And determines one of the steering angle and the steering angle. 11. The method of claim 10,
The steering state determination unit determines the square root of the characteristic speed square value as the characteristic speed value when the characteristic speed square is a positive value, and determines the slip-state understeer state when the current vehicle speed is greater than the characteristic speed value , And if the current vehicle speed is smaller than the characteristic speed value, it is determined to be a simple understeer state. 11. The method of claim 10,
Wherein the steering state determiner determines a square root of an absolute value of a characteristic speed square value as a critical speed value when the characteristic speed square is a negative value and when the current vehicle speed is greater than a critical speed value, State, and when the current vehicle speed is smaller than the threshold speed value, it is determined to be a simple oversteer state. 10. The method of claim 9,
The steered state determining unit may determine whether the current vehicle speed is equal to or less than the threshold vehicle speed, the vehicle speed, the steering angle and the yaw rate, and the condition that the yaw rate gain error calculated from the wheel base between the vehicle front- And if so, a neutral steering state. A measurement information receiving step of receiving measurement information from a sensor unit including a vehicle speed sensor, a steering angle sensor and a yaw rate sensor;
A vehicle characteristic information extracting step of reading vehicle characteristic information from a storage unit storing vehicle characteristic information;
A steering angle and a yaw rate of the vehicle received from the sensor unit, and vehicle characteristics information of a wheelbase between the front and rear wheels of the vehicle and a rotation ratio of the front wheel rotational angle read from the storage unit A steering state determining step of determining a current steering state of the vehicle by using the steering state determining step;
A compensating step of generating a compensating torque for compensating for an abnormal steering state and outputting the compensation torque to the steering control part;
A steering control step of generating a steering assist current by using the applied steering torque applied to the steering wheel and the compensating torque to control the steering motor;
And a steering angle of the steering wheel. 15. The method of claim 14,
In the steering state determination step, the vehicle speed, the steering angle, and the yaw rate are measured and the vehicle characteristic information of the wheel base and the steering angle / (Positive or negative) of a characteristic speed square and a characteristic speed value or critical speed value derived from the characteristic speed square value and an actual steering speed according to a magnitude relation between the present vehicle speed and an abnormal steering State of the steering wheel is determined. 16. The method of claim 15,
In the steering state determination step, when the characteristic speed square is a positive value, the square root of the characteristic speed square value is determined as the characteristic speed value. When the current vehicle speed is greater than the characteristic speed value, the sleeping understeer state , And when the present vehicle speed is smaller than the characteristic speed value, it is determined to be a simple under-steering state. 16. The method of claim 15,
In the steering state determination step, when the characteristic speed square is a negative value, the square root of the absolute value of the characteristic speed square value is determined as a critical speed value. When the current vehicle speed is greater than the critical speed value, Steer state, and when the present vehicle speed is smaller than the critical speed value, it is determined to be a simple oversteer state. 15. The method of claim 14,
In the steering state determination step, at least one of a condition that the present vehicle speed is equal to or less than a critical vehicle speed, a vehicle speed, a steering angle and a yaw rate, and a condition that a yaw rate gain error calculated from a wheel base between the vehicle front- The steering control system determines that the vehicle is in the neutral steering state. 15. The method of claim 14,
Wherein the compensating step determines that the compensating torque is proportional to the vehicle speed, the steering angle and the yaw rate, and the yaw rate gain error value calculated from the wheel base between the front and rear wheels of the vehicle. 15. The method of claim 14,
In the steering control step, when the steered state is an understeer with slip, the control is performed so that the applied steering torque is reduced by a compensating torque, and when the steered state is an unstable oversteer, the compensating torque is added to the applied steering torque Wherein the steering control method comprises the steps of:

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