KR100799972B1 - Steering assist control method and vehicle's attitude adjusting apparatus - Google Patents

Abstract

An apparatus and a method for controlling a steering operation for a vehicle attitude adjusting apparatus are provided to prevent a vehicle from moving toward one side upon asymmetrical friction of a road by compensating for a steering control using pressure information of left and right wheels. A method for controlling a steering operation for a vehicle attitude adjusting apparatus comprises the step of determining if a road is in a sprit-mu condition. If the road is in the sprit-mu condition, pressure difference information of a left wheel and a right wheel is calculated. A compensation torque value for controlling a steering is determined using the calculated pressure difference information and yaw variation information. A steering angle for the vehicle is controlled based on the compensation torque value.

Description

Steering assist control method and apparatus for vehicle attitude control apparatus

1 is an exemplary view showing a vehicle on a road surface having both frictional forces different from each other.

2 is a block diagram illustrating a steering cooperative control method according to an embodiment of the present invention.

3 is a simple operation flowchart of the vehicle attitude control device shown in FIG.

4A and 4B are graphs showing test results of a conventional vehicle and a vehicle performing a steering cooperative control method according to an embodiment of the present invention.

5 is an exemplary view showing the behavior of a conventional vehicle and a vehicle performing a steering cooperative control method according to an embodiment of the present invention on a chess board.

FIG. 6 is a graph showing test results of a vehicle performing the steering cooperative control method illustrated in FIG. 5.

<Explanation of symbols for the main parts of the drawings>

100: vehicle memory 200: vehicle attitude control device

210: braking control unit 220: road surface determination unit

230: steering coordination unit 231: yaw change calculation unit

232: pressure difference calculation unit 233: steering coordination control unit

300: braking device 400: steering device

500: yaw sensor 600: pressure sensor

700: steering angle sensor 800: vehicle speed sensor

900: Lateral Acceleration Sensor

)라 칭함)에서 휠의 조향각을 차량이 직진방향으로 제동되도록 조향각을 제어하는 차량 자세 제어 장치의 조향 협조 제어 및 그 장치에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle attitude control apparatus and a control method thereof, and more particularly to an asymmetric friction road surface (hereinafter, split_mu).

The steering angle control wheel and steering apparatus of the vehicle attitude control device for controlling the steering angle so that the vehicle is braking in a straight direction.

When a vehicle is suddenly braked in a place where the frictional force on both sides of the road is different, the vehicle body tends to lean toward the higher frictional force.

1 is an exemplary view showing a vehicle on a road surface having both frictional forces different from each other.

Referring to FIG. 1, the vehicle is very dangerous because it is slid from the low friction side (the left ice of the vehicle shown in FIG. 1) and is directed to the high friction side (the right pavement of the vehicle shown in FIG. 1). .

Therefore, companies use anti-lock braking (ABS) to reduce the difference between the left and right braking force on the front wheels and to lower the braking force on the rear wheels, and to drive the steering system using additional sensors. Incorporating a number of electronic controls (such as Electronic Stability Control (ESC), Active Front Steering (AFS) and Active Roll Stabilization (ARS)) BACKGROUND ART Researches for controlling vehicle behavior with electronic cooperative control devices (such as vehicle dynamics management (VDM)) have been actively conducted.

These research trends show that individual systems, such as brakes, have limitations in controlling the car on special roads such as split mues.

As a result, individual systems such as vehicle stability control (ESC), active front wheel steering (AFS), and electric power steering (EPS) systems are integrated into the Unified Chassis Control (UCC) system. In addition, the necessity of developing logic to improve the stability of the vehicle by sharing sensor information and control information of individual systems has emerged.

SUMMARY OF THE INVENTION The present invention has been devised for this need. When the vehicle is braking in a place where the frictional force of both road surfaces is different (split mu or a chess board), the vehicle controlling the steering angle of the wheel so that the vehicle is braked in a straight direction. The object is to provide a posture control device and its control method.

Another object of the present invention is to provide a vehicle attitude control device and a method of controlling the steering angle of a wheel so that the vehicle brakes in a straight direction even when the frictional force of both road surfaces enters another place after the vehicle is braked.

According to an aspect of the present invention for achieving the above object, if the braking is driven, the step of determining whether the current road surface is a split mu, and if the current road surface is determined to be split mu, the pressure difference between the left and right wheels of the vehicle Calculating information, determining the compensation torque value of the steering control of the vehicle using the calculated pressure difference information, and controlling the steering angle of the vehicle based on the determined compensation torque value. A steering cooperative control method for a vehicle attitude control device is provided.

Preferably, the determining step is characterized by determining the compensation torque value of the steering control of the vehicle using the yaw change information of the vehicle together with the pressure difference information of the left and right wheels.

More preferably, the determining step includes calculating moments corresponding to the yaw change information and the pressure difference information of the left and right wheels, respectively, and determining the compensation torque value of the steering control using the calculated moments. Characterized in that.

Even more preferably, the determining step is characterized by calculating the calculated torque by calculating the moments calculated.

According to another aspect of the present invention, a braking control unit that performs braking control on the left and right wheels of the vehicle, and a road surface determination unit that determines whether the current road surface is split mui when the left and right wheels are braked by the braking control unit. And a steering coordination unit configured to determine a compensation torque value of steering control by using pressure information of left and right wheels of the vehicle when the current road surface is determined to be split mu by the road surface determination unit. Provide a posture control device.

Preferably, the steering cooperative unit is a pressure calculation unit for calculating the pressure difference information of the left and right wheels using the pressure information of the left and right wheels of the vehicle, the compensation of the steering control according to the pressure difference information calculated by the pressure calculation unit It is configured to include a steering coordination control unit for determining the torque value.

More preferably, the vehicle attitude control apparatus further includes a yaw change calculation unit that calculates yaw change information of the vehicle using yaw rate information of the vehicle, wherein the steering coordination control unit is configured to calculate the pressure difference information of the left and right wheels and the calculated yaw rate information. The compensation torque value of the steering control is determined by using yaw change information.

Even more preferably, the steering cooperative control unit calculates the moments corresponding to the pressure difference information and the yaw change information of the left and right wheels, respectively, and calculates the calculated moments to determine the compensation torque value.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a block diagram illustrating a method of controlling a vehicle attitude control apparatus according to an embodiment of the present invention.

Referring to FIG. 2, an electronic control system for a vehicle includes a vehicle memory 100 storing environment information and vehicle driving information necessary for controlling a vehicle, and a vehicle attitude control apparatus 200 for controlling a vehicle braking and a vehicle attitude during braking. And a plurality of sensors (yaw sensor 500, pressure sensor 600, steering angle sensor 700, vehicle speed sensor) for outputting sensor values measured in the vehicle, the braking device 300, the steering device 400, and the vehicle. 800, the lateral acceleration sensor 900 is configured.

The vehicle attitude control device 200 may include a braking control unit 210 that performs driving and anti-lock braking control functions of the braking device 300, a road surface determination unit 220 that determines whether a current road surface is a split mu, And a steering coordination unit 230 for determining a compensation torque value of the steering control of the vehicle.

The braking control unit 210 drives the braking device 300 according to a known braking control method in accordance with a braking control signal received from the outside, and is applied to the left and right wheels of the vehicle according to the known anti-lock braking control method. Performs an anti-lock braking function.

The road surface determination unit 220 serves to determine whether the current road surface is split mute based on a known road surface determination method.

When the steering coordination unit 230 determines that the current road surface is the split mu by the road surface determination unit 220, the compensation torque of the steering control for improving the stability of the behavior of the vehicle in the split mu according to an embodiment of the present invention. The value is determined and sent to the steering apparatus 400.

To this end, the steering coordination unit 230 includes a pressure difference calculator 232 for calculating pressure difference information of the left and right wheels of the vehicle and a yaw change information of the vehicle, in order to determine a compensation torque value of the steering control. And a steering cooperative control unit 233 for calculating a compensation torque value of steering control by using the change calculator 231 and the calculated pressure difference information and yaw change information.

The pressure difference calculator 232 receives the pressure information of both sides from the pressure sensor 600 and calculates the difference between the pressure information of both sides.

The yaw change calculation unit 231 calculates yaw change information using the yaw information input from the yaw sensor 500.

The steering coordination control unit 233 calculates respective moments corresponding to the calculated pressure difference information and yaw change information, and determines the steering compensation torque value using each moment.

In detail, the steering coordination control unit 233 calculates a moment based on yaw change information based on a known steering control method according to a known yaw change, and calculates a moment based on pressure difference information according to an embodiment of the present invention. , By multiplying the pressure difference information by a predetermined gain) and determining the compensation torque value through calculation (eg, sum) of each moment, but the present invention is not limited thereto.

In addition, the steering coordination control unit 233 sets the determined compensation torque value to a value controlled to the left or right based on yaw change information according to an embodiment of the present invention, and then sets the set compensation torque value to the steering device ( 400, but the present invention is not limited thereto.

3 is a simple operation flowchart of the vehicle attitude control device 100 according to an embodiment of the present invention. Referring to FIG. 3, the braking control unit 210 controls the braking device 300 in response to an input control signal (S1).

Next, the road surface determination unit 220 determines whether the current road surface is split mute based on a known road surface determination method (S2).

Next, the yaw change calculation unit 231 calculates yaw change information by using yaw information input from the yaw sensor 500 (S3).

Next, the pressure difference calculator 232 calculates pressure difference information of both wheels by using pressure information of the left and right wheels of the vehicle input from the pressure sensor 600 (S4).

Next, the steering coordination control unit 233 calculates moments corresponding to the yaw change information and the corresponding pressure difference information by using the yaw change information calculated in step S3 and the pressure difference information calculated in step S4. To determine the compensation torque value of the steering control (S5).

At this time, the compensation torque value determined by the step S5 is transmitted to the steering device 400 through the CAN (), the steering device 400 controls the steering angle of the vehicle based on the transmitted compensation torque value.

(Ice+Dry Asphalt)) 노면에서 조향 협조 제어 방법을 수행하지 않는 차량이 제동시 핸들을 수동으로 조작하지 않는 경우에 측정되는 차량 정보를 나타내는 그래프이고, 도 4b는 도 4a와 동일한 스프릿 뮤 노면에서 본 발명의 일실시예에 따른 조향 협조 제어 방법을 수행하는 차량이 제동시 핸들을 수동으로 조작하지 않는 경우에 측정되는 차량 정보를 나타내는 그래프이다.4A shows split mu

(Ice + Dry Asphalt)) This is a graph showing vehicle information measured when a vehicle that does not perform the steering cooperative control method on the road surface does not manually operate a steering wheel. A graph showing vehicle information measured when a vehicle performing a steering cooperative control method according to an embodiment of the present invention does not manually operate a steering wheel during braking.

In this case, the vehicle information shown in FIGS. 4A and 4 includes a yaw rate, a steering angle, and a vehicle speed.

First, it can be seen that the maximum yaw rate of the vehicle of FIG. 4A is 20 deg / sec, and the maximum yaw rate of the vehicle of FIG. 4B is 3.13 deg / sec.

As a result of comparative experiments, the yaw rate maximum value of the vehicle of FIG. 4B is reduced by about 80% compared to the maximum value of the yaw rate of the vehicle of FIG. 4A. In FIG. 4B, the braking distance of the vehicle of FIG. 4B was shortened by about 5% compared to the braking distance of the vehicle of FIG. 4A.

5 is an exemplary view showing the behavior of the vehicle and the vehicle that does not perform the steering cooperative control method according to an embodiment of the present invention on the chessboard, Figure 6 is a handle when the vehicle braking the steering cooperative control method This is a graph showing vehicle information measured when the manual operation is not performed.

The vehicle information shown in FIG. 6 includes a yaw rate, a steering angle, and a vehicle speed calculated from the vehicle.

Referring to FIG. 6, the maximum yaw rate of the vehicle performing the steering cooperative control method is 7.57 deg / sec, which is relatively stable, and the steering engine is about 25 deg / sec to +25 deg / sec. It can be seen that braking (see FIG. 5) becomes possible.

According to the present invention, the braking control device compensates the steering control by using the pressure information of the left and right wheels of the vehicle during braking, thereby preventing the vehicle's behavior from being pulled to one side by different frictional forces of the road surface in the split mu, and braking straight. It is effective to make.

Claims (8)

Determining whether the current drawing is a split mu, when braking is driven, If it is determined that the current road surface is split mu, calculating pressure difference information between left and right wheels of the vehicle; Determining the compensation torque value of the steering control of the vehicle using the calculated pressure difference information, and determining the compensation torque value of the steering control of the vehicle using the yaw change information of the vehicle together with the pressure difference information of the left and right wheels. Wow, And controlling the steering angle of the vehicle based on the determined compensation torque value. delete The method of claim 1, wherein the determining step Calculating moments corresponding to the yaw change information and the pressure difference information of the left and right wheels, respectively; And determining the compensation torque value of the steering control by using the calculated moments. The method of claim 3, wherein the determining step And calculating the compensation torque value by calculating the calculated moments. A braking control unit which performs braking control on the left and right wheels of the vehicle, A road surface determination unit that determines whether the current road surface is split mu, when the left and right wheels are braked by the braking control unit; If it is determined by the road surface determination unit that the current road surface is split mu, steering steering unit for determining the compensation torque value of the steering control using the pressure information of the left and right wheels of the vehicle, The steering cooperative unit may include a pressure calculator configured to calculate pressure difference information of the left and right wheels using pressure information of the left and right wheels of the vehicle, and a compensation torque value of steering control according to the pressure difference information calculated by the pressure calculator. And a steering cooperative control unit for determining. delete The method according to claim 5, Further comprising a yaw change calculation unit for calculating yaw change information of the vehicle by using the yaw rate information of the vehicle, The steering coordination control unit And a compensation torque value of the steering control by using the pressure difference information of the left and right wheels and the calculated yaw change information. The method of claim 7, wherein the steering coordination control unit And calculating moments corresponding to the pressure difference information of the left and right wheels and the yaw change information, and calculating the calculated torques to determine the compensation torque value.

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