KR20120008621A - Electronic stability control apparatus by using wheel lateral acceleration - Google Patents

Abstract

PURPOSE: A vehicle posture control apparatus using wheel horizontal acceleration is provided to control the brake pressure on an each wheel based on a calculated wheel lateral slip angle. CONSTITUTION: A vehicle posture control apparatus using wheel horizontal acceleration comprises a measuring unit(100), a data acquisition unit(110), and a controller(120). The measuring unit measures the horizontal acceleration in the wheel. The data acquisition unit receives the wheel horizontal acceleration information. The controller calculates the lateral slip angle based on wheel lateral acceleration signals. The controller controls the brake pressure of each wheel based on the wheel lateral slip angle.

Description

Vehicle attitude control device using wheel lateral acceleration {ELECTRONIC STABILITY CONTROL APPARATUS BY USING WHEEL LATERAL ACCELERATION}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for performing electronic stability control (ESC), and more particularly, to a vehicle attitude control apparatus using wheel lateral acceleration suitable for performing vehicle attitude control by measuring lateral acceleration at a wheel.

In general, the vehicle attitude control (ESC) method is also called ESP (Electronic Stability Program) or VDC (Vehicle Dynamic Control), and the road conditions such as slippery roads due to rain, snow, and sand during driving and sudden zigzag driving When the vehicle's posture is unstable due to exercise inertia, it is to maintain the vehicle's posture stably and to maintain the posture of the vehicle stably by controlling the brake and engine torque in a dangerous posture.

The vehicle attitude control (ESC) determines the state of the vehicle and the road surface state through a plurality of sensors such as a wheel speed sensor, a brake pressure sensor, a steering angle sensor, a yaw rate sensor, a lateral acceleration sensor, and the like. To determine whether the vehicle is under steer or over steer and to braking the inner and outer wheels to control the vehicle's attitude to a stable state. A method of controlling the vehicle attitude based on the measured lateral force of the wheel using a change in the rotational speed of the retainer has been proposed.

In the conventional vehicle attitude control system operating as described above, the wheel lateral force is measured using the change in the rotational speed of the retainer caused by the change of the contact angle of the hub bearing ball, and the vehicle attitude control is measured using the measured lateral force of the wheel. However, the vehicle attitude control method using the lateral force of the wheel as described above has a problem in that the contact angle is frequently changed due to the change in contact angle and rotational wear in the assembling process so that the reliability may be deteriorated and the structure is complicated.

Accordingly, the present invention provides a vehicle attitude control apparatus using wheel lateral acceleration that can measure lateral acceleration at a wheel to perform vehicle attitude control.

In addition, the present invention, by measuring the lateral acceleration in the wheel, calculates the lateral slip angle of the front wheel based on the measured wheel lateral acceleration information, the wheel that can control the brake pressure of each wheel based on the calculated wheel lateral slip angle Provided is a vehicle attitude control device using lateral acceleration.

According to an embodiment of the present invention, an apparatus includes a measuring unit for measuring lateral acceleration in a wheel, a data obtaining unit for receiving and processing wheel lateral acceleration information measured by the measuring unit, and a wheel lateral acceleration in which the data obtaining unit processes a signal. And a control unit for calculating the front and rear wheel side slip angles based on the signal, and controlling the brake pressure of each wheel based on the calculated wheel side slip angle.

The control unit may calculate the wheel lateral slip angle by using the wheel lateral acceleration signal, the wheel speed signal, the yaw rate signal, and the steering angle signal.

The controller may calculate the wheel lateral slip angle through the following equation.

,

,

는 전륜 휠 횡 슬립각,

은 후륜 휠 횡 슬립각,

은 전륜 휠 횡가속도,

은 후륜 휠 횡가속도,

는 전륜 휠 종속도,

는 후륜 휠 종속도,

은 차체 요레이트,

은 조향각임.here,

Front wheel lateral slip angle,

Silver rear wheel lateral slip angle,

Front wheel lateral acceleration,

Rear wheel lateral acceleration,

Front wheel wheel dependent road,

Rear wheel dependent road,

Silver body yorate,

Is the steering angle.

The control unit may determine an understeer or an oversteer using the size of the wheel lateral slip angle, and determine the pressure of the entire brake using the difference of the wheel lateral slip angle.

On the other hand, the measuring unit, the lateral acceleration measuring unit for measuring the lateral acceleration in the wheel, the wheel speed measuring unit for measuring the wheel speed in the travel direction, the measuring unit for measuring the yaw rate of the vehicle, the steering angle measuring unit for measuring the steering angle It is characterized by including.

The vehicle attitude control device may further include a brake pressure measuring unit configured to measure the pressure applied to the brake in real time and transmit the measured pressure to the controller.

In the present invention, effects obtained by representative ones of the disclosed inventions will be briefly described as follows.

The present invention, by using the vehicle posture control device using the wheel lateral acceleration to detect the time of sliding the vehicle at the snow road, ice road or high-speed turning than the conventional ESC vehicle control system to start the vehicle control to improve safety It is possible to prevent the accident caused by the lateral slip in advance.

1 is a block diagram showing the structure of a vehicle attitude control apparatus according to an embodiment of the present invention;
2 is a block diagram showing the structure of a measuring unit according to an embodiment of the present invention;
3 is a flowchart illustrating an operation procedure of the vehicle attitude control apparatus according to an embodiment of the present invention;
4 is a flowchart illustrating an operation procedure of the vehicle attitude control apparatus according to another embodiment of the present invention;
5A to 5C are graphs showing simulation results for vehicle attitude control performance according to an embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be based on the contents throughout this specification.

Combinations by each block in the accompanying block diagrams may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions executed by the processor of the computer or other programmable data processing equipment are described in each block of the block diagram. It creates a means to perform the functions. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in each block of the block diagram. Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions that perform processing equipment may also provide steps for executing the functions described in each block of the block diagram.

In addition, each block may represent a portion of a module, segment, or code that includes one or more executable instructions for executing a specified logical function (s). It should also be noted that in some alternative embodiments, the functions noted in the blocks may occur out of order. For example, the two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the corresponding function.

An embodiment of the present invention is to perform the vehicle attitude control by measuring the lateral acceleration at the wheel, by measuring the lateral acceleration at the wheel, and calculating the front and rear wheel lateral slip angle based on the measured wheel lateral acceleration information, The brake pressure of each wheel is controlled based on the wheel lateral slip angle. Existing vehicle attitude control device (ESC) is controlled by measuring the lateral acceleration signal measured at the outer ring or knuckle of the hub bearing, that is, the lateral acceleration in the vehicle body, in the embodiment of the present invention by measuring the lateral acceleration in the wheel to control This allows for fast and improved control.

1 is a block diagram showing the structure of a vehicle attitude control apparatus according to an embodiment of the present invention, Figure 2 is a block diagram showing the structure of a measuring unit according to an embodiment of the present invention.

Referring to FIG. 1, the vehicle attitude control apparatus may include a measurement unit 100, a data acquisition unit 110, a controller 120, a brake 130, a brake pressure measurement unit 132, and the like.

Specifically, the measurement unit 110 measures information necessary for vehicle attitude control and transmits the measured data to the data acquisition unit 110. As shown in FIG. 2, the lateral acceleration measurement unit 102 and the wheel speed are shown. The measuring unit 104, the yaw rate measuring unit 106 and the steering angle measuring unit 108 may be included.

Here, the lateral acceleration measurement unit 102 measures the lateral acceleration for the front wheel and the rear wheel through the lateral acceleration sensor attached to each wheel, the wheel speed measurement unit 104 is the front wheel as the speed of the wheel with respect to the vehicle's forward direction And wheel dependence on the rear wheels. In addition, the yaw rate measuring unit 106 may measure the yaw rate based on the yaw rate sensor of the vehicle body, and may measure the steering angle through the steering angle sensor detecting the steering angle of the steering wheel of the steering angle measuring unit 108.

The data acquiring unit 110 receives the data measured by the measuring unit 100, processes the signal, and then transmits the signal to the control unit 120. The lateral acceleration measuring unit 102 of the measuring unit 100 and the wheel speed measuring unit ( 104) periodically obtains various results (lateral acceleration, wheel speed, yaw rate, steering angle, etc.) provided from the yaw rate measuring unit 106 and the steering angle measuring unit 108, and the like. Through the signal processing, the processing data may be synchronized and provided to the controller 120.

The brake 130 receives the pressure adjustment control signal from the controller 120 to perform hydraulic pressure adjustment of the brake, and the brake pressure measurement unit 132 detects the pressure applied to the brake, for example, a pressure inside the master cylinder. By transmitting to the controller 120, the controller 120 may determine whether the brake is braked in the vehicle.

The controller 120 calculates wheel lateral slip angles for the front wheels and the rear wheels based on the lateral acceleration signal, the wheel speed signal, the yaw rate signal, and the steering angle signal received from the data acquisition unit 110, and calculates the calculated wheel slip angles for the front wheels and the rear wheels. The ratio of the lateral slip angle can be used to derive a value for continuously distributing the brake force of each wheel.

On the other hand, a control model for calculating the wheel lateral slip angle using the lateral acceleration measured in the wheel can be implemented based on Equation 1 below.

[Equation 1]

,

,

는 전륜 휠 횡 슬립각,

은 후륜 휠 횡 슬립각,

은 전륜 휠 횡가속도,

은 후륜 휠 횡가속도,

는 전륜 휠 종속도,

는 후륜 휠 종속도,

은 차체 요레이트,

은 조향각이다.here,

Front wheel lateral slip angle,

Silver rear wheel lateral slip angle,

Front wheel lateral acceleration,

Rear wheel lateral acceleration,

Front wheel wheel dependent road,

Rear wheel dependent road,

Silver body yorate,

Is the steering angle.

And the ratio of the wheel lateral slip angle with respect to the front wheel and the rear wheel can be calculated based on Equation 2 below.

[Equation 2]

,

,

과

은 각각 전륜 및 후륜에 대한 휠 횡 슬립각 비이다.here,

and

Is the wheel lateral slip angle ratio for the front and rear wheels, respectively.

In addition, the controller 120 determines whether it is understeer or oversteer using the magnitudes of the front and rear wheel lateral slip angles calculated by Equation 1, and determines whether the brake is understeered or oversteered. The vehicle attitude control may be performed by adjusting the pressure of 130.

At this time, the pressure to be controlled to the entire brake 130 may be determined using the difference between the front and rear wheel slip angles, and the pressure may be continuously distributed to the brakes 130 of the wheels using the front wheel and rear wheel horizontal slip angle ratios.

3 is a flowchart illustrating an operation procedure of the vehicle attitude control apparatus according to an embodiment of the present invention.

Referring to FIG. 3, in step 300, the lateral acceleration measuring unit 102 of the measuring unit 100 measures the lateral acceleration in the wheel, and in step 302, the wheel speed measuring unit 104 determines the wheel in the traveling direction of the vehicle. Measure the speed.

In operation 304, the yaw rate measuring unit 106 measures the yaw rate of the vehicle body. In step 306, the steering angle measuring unit 108 measures the steering angle of the vehicle steering wheel, and each measured data is obtained by the data obtaining unit 110. And the signal is processed, the signal processed information is transmitted to the control unit 120.

The controller 120 calculates the wheel lateral slip angles for the front wheels and the rear wheels based on the measurement signals including the wheel lateral acceleration signals in step 308, and uses the ratio of the wheel lateral slip angles for the front wheels and the rear wheels in step 310. The pressure of the brake for each wheel is distributed, and the distributed pressure control command is transmitted to the brake 130.

4 is a flowchart illustrating an operation procedure of the vehicle attitude control apparatus according to another embodiment of the present invention.

Referring to FIG. 4, in operation 400, the lateral acceleration measurement unit 102 of the measurement unit 100 measures the lateral acceleration of the wheels at each wheel of the vehicle, and in step 402, the wheel speed measurement unit 104 proceeds with the vehicle. As wheel speed relative to direction, the wheel dependency is measured.

In operation 404, the yaw rate measuring unit 106 measures the yaw rate of the vehicle body. In operation 406, the steering angle measuring unit 108 measures the steering angle of the vehicle steering wheel, and each measured data is obtained by the data obtaining unit 110. And the signal is processed, and the signal processed information is transmitted to the controller 120.

Accordingly, the control unit 120 calculates the wheel lateral slip angles for the front wheels and the rear wheels based on the measurement signals including the wheel lateral acceleration signals in step 408, and uses the magnitude of the wheel lateral slip angles for the front wheels and the rear wheels in step 410. To determine whether it is understeer or oversteer.

In step 412, after the understeer or oversteer is determined, the pressure to be controlled for the entire brake 130 is determined using the difference between the front and rear wheel slip angles, and in step 414, each wheel is determined using the front and rear wheel slip ratios. The pressure is continuously distributed to the brake 130.

5A to 5C are graphs showing simulation results of vehicle attitude control performance according to an embodiment of the present invention, in which the vertical axis represents an angular velocity and the horizontal axis represents an angle, thereby determining a horizontal slip amount. Can be.

5A is a performance graph using a conventional vehicle attitude control method, and FIG. 5B is a performance graph in which pressure distribution of the brake is improved through an embodiment of the present invention, and the amount of lateral slip can be reduced by about 22% compared with the conventional method. It can be confirmed.

In addition, Figure 5c is a performance graph to further improve the pressure distribution of the brake and the determination of the understeer and oversteer through another embodiment of the present invention, it can be confirmed that the amount of lateral slip can be reduced by 22% compared to the conventional Can be.

As described above, an embodiment of the present invention is to perform vehicle attitude control by measuring lateral acceleration at a wheel, and measure lateral acceleration at the wheel, and determine the front and rear wheel lateral slip angles based on the measured wheel lateral acceleration information. It calculates and controls the brake pressure of each wheel based on the calculated wheel side slip angle. By performing the vehicle attitude control using the wheel lateral acceleration as described above, it is possible to bring the control point faster than the existing vehicle attitude control device, thereby improving stability, thereby preventing an accident such as an extreme situation in which the vehicle slips severely. Can be.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

100: measuring unit 102: lateral acceleration measuring unit
104: wheel speed measuring unit 106: yaw rate measuring unit
108: steering angle measurement unit 110: data acquisition unit
120: control unit 130: brake
132: brake pressure measuring unit

Claims (7)

Measuring unit for measuring the lateral acceleration on the wheel,
A data acquisition unit for receiving and processing wheel lateral acceleration information measured by the measurement unit;
A controller for calculating front and rear wheel lateral slip angles based on the wheel lateral acceleration signal processed by the data acquisition unit and controlling brake pressure of each wheel based on the calculated wheel lateral slip angle
Vehicle attitude control device using a wheel lateral acceleration including a. The method of claim 1,
The control unit,
And the wheel lateral slip angle is calculated using the wheel lateral acceleration signal, the wheel speed signal, the yaw rate signal, and the steering angle signal. The method of claim 1,
The control unit,
Vehicle attitude control apparatus using the wheel lateral acceleration, characterized in that for calculating the wheel side slip angle through the following equation.

,

here,

Front wheel lateral slip angle,

Silver rear wheel lateral slip angle,

Front wheel lateral acceleration,

Rear wheel lateral acceleration,

Front wheel wheel dependent road,

Rear wheel dependent road,

Silver body yorate,

Is the steering angle. The method of claim 3, wherein
The control unit,
Vehicle attitude control device using a wheel lateral acceleration characterized in that to distribute the brake pressure of each wheel by using the wheel lateral slip angle ratio for the front wheel and the rear wheel calculated through the following equation.

,

here,

and

Is the wheel lateral slip angle ratio for the front and rear wheels, respectively. The method of claim 1,
The control unit,
Understeer or oversteer is determined using the size of the wheel lateral slip angle,
The vehicle attitude control apparatus using the wheel lateral acceleration, characterized in that for determining the pressure of the entire brake by using the difference of the wheel side slip angle. The method of claim 1,
The measuring unit,
Lateral acceleration measurement unit for measuring the lateral acceleration on the wheel,
A wheel speed measuring unit for measuring the wheel speed in a traveling direction;
A measurement unit for measuring the vehicle yaw rate,
Steering angle measuring unit for measuring steering angle
Vehicle attitude control device using the wheel lateral acceleration, characterized in that it comprises a. The method of claim 1,
The vehicle attitude control device,
Brake pressure measuring unit for measuring the pressure applied to the brake in real time to deliver to the controller
Vehicle attitude control device using the wheel lateral acceleration, characterized in that it further comprises.

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