KR19990059747A - Control Mode Determination Method of Traction Control System - Google Patents

Abstract

The present invention relates to a control mode determination method of a traction control system for controlling a traction of a vehicle through an appropriate control mode according to a driving road situation. After calculating the target speed of the drive wheels and detecting the speed of each drive wheel, the wheel speed of the counterpart drive wheel after a predetermined time after the wheel slip has been restored by the control of one drive wheel in which excessive slip has occurred is equal to or greater than the calculated drive wheel target speed and the average of both drive wheels If it is greater than the speed, it is determined as a uniform road surface and the engine output control mode is set for traction control, and the wheel speed of the counterpart drive wheel after a predetermined time after the wheel slip is restored by the control of one drive wheel that has excessive slip is less than the calculated drive wheel target speed. If it is less than the average speed of both driving wheels, it is judged as asymmetric road surface As to set the brake control mode improves the driving stability of the vehicle by the traction control, but also to maximize the effect of the traction control.

Description

Control Mode Determination Method of Traction Control System

The present invention relates to a traction control system (TRACTION CONTROL SYSTEM), and more particularly to a control mode determination method of the traction control system to control the traction of the vehicle through the appropriate control mode according to the situation of the driving road. .

In general, when the accelerator is stepped and accelerated on a slippery road surface while the vehicle is in operation, the driving wheels may revolve and the vehicle may not move, or the vehicle may be sideways and become dangerous.

In order to prevent this, a traction control system has been developed, and the traction control controls the driving wheels at a slip ratio in the traction control area without the driver's accelerator control when the vehicle is accelerated to secure sufficient corner force and driving force. It is. As a method of detecting slip of the driving wheel to act in the traction control region, there is a method of controlling engine output control and driving wheel brake.

Engine output control operates in the uniform road surface and the entire speed range by lowering the engine output through opening and closing of the throttle valve, reducing or blocking fuel injection amount, and ignition timing, and driving wheel brake control directly controls the driving wheel itself. It is effective for escape from muddy roads and asymmetric roads and slopes below medium to low speeds.

In the traction control system as described above, the engine power control and the driving wheel brake control should be appropriately performed according to the driving road condition, that is, the uniform road surface, the asymmetric road surface, and the like. Otherwise, the driving wheels of the vehicle are not controlled at an appropriate slip ratio, and thus the stability of the vehicle is not secured.

For example, when the driving wheel brake control is performed on a uniform road surface, a phenomenon such as a hunt (HUNT) in which the driving direction of the vehicle moves from side to side occurs, thereby preventing stable driving.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to identify a driving road state of a vehicle at an early stage so that proper traction control is achieved.

1 is a block diagram schematically illustrating a traction control system according to the present invention;

2 is a flowchart illustrating a control mode determination method of a traction control system according to the present invention;

3 and 4 are signal waveform diagrams showing the speed of each drive wheel due to the initial excessive slip of the actual vehicle, FIG. 3 is a uniform road surface, and FIG. 4 is a drive wheel speed on an asymmetric road surface.

In order to achieve the above object, the present invention is to detect the speed of the vehicle body during acceleration of the vehicle, calculate the target speed of the drive wheel for controlling to the slip ratio in the traction control region, detect the speed of each drive wheel, and then excessive slip If the wheel speed of the counterpart drive wheel after the predetermined time after the wheel slip is restored by the control of the generated one side drive wheel is greater than the calculated drive wheel target speed and is greater than the average speed of both drive wheels, it is determined that the road surface is uniform and the engine output control mode is set for traction control. do.

When the vehicle is accelerated, the target speed of the driving wheel for detecting the speed of the vehicle and controlling the slip rate in the traction control region is calculated, the speed of each driving wheel is detected, and the wheel slip is recovered by the control of one side of the driving wheel in which excessive slip occurs. If the wheel speed of the counterpart drive wheel after the predetermined time is less than the calculated drive wheel target speed and smaller than the average speed of both drive wheels, it is determined that it is an asymmetric road surface, and the drive wheel brake control mode is set to perform traction control.

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

As can be seen in FIG. 1, the traction control system according to the present invention includes a vehicle speed sensor 11, a wheel speed sensor 12, a traction control unit 20, a brake control unit 31, and an engine output control unit 32.

The vehicle speed sensor 11 detects the traveling speed of the vehicle (body) while the vehicle is running and outputs a predetermined signal accordingly.

The wheel speed sensor 12 detects the rotational speed of the driving wheel while the vehicle is running and outputs a predetermined signal accordingly.

The traction control unit 20 analyzes the signals of the vehicle speed sensor 11 and the wheel speed sensor 12 to grasp the state of the current driving road, and selects an appropriate traction mode accordingly so that traction control is performed.

The brake control unit 31 operates according to the signal of the traction control unit 20 to control the driving wheel brake.

The engine output control unit 32 controls the engine output by controlling the opening and closing of the throttle valve, the fuel injection amount, and the ignition timing according to the signal of the traction control unit 20.

The traction control mode determination method according to an embodiment of the present invention in the traction control system configured as described above will be described in detail with reference to the accompanying drawings.

When the driver accelerates by pressing the accelerator pedal during the initial driving of the vehicle or during the driving of the vehicle, the traction control unit 20 analyzes a signal received from the vehicle speed sensor 11 to detect the vehicle speed (body speed) V (S1), The target speed TW of the drive wheels for controlling the drive wheels at the slip ratio in the traction control region is calculated according to the detected vehicle speed V (S2).

That is, since the slip rate during acceleration of the vehicle is expressed as in Equation 1 below, it can be easily obtained from the speed of the detected vehicle body.

Thereafter, the traction control unit 20 analyzes a signal received from the wheel speed sensor 12 to detect wheel speeds WL and WR of each driving wheel (S3), and travels according to the detected wheel speeds WL and WR of each driving wheel. Determine the state of the road (S4).

At this time, since the initial excessive driving wheel slip is transferred to the one side driving wheel WL due to the influence of the differential gear, the wheel speed WR of the opposite side driving wheel in which excessive slip has occurred is almost similar to the vehicle speed V as shown in FIGS. 3 and 4. Done. Subsequently, the wheel speed WL of the driving wheel is restored by the control of the driving wheel WL, and after the predetermined time T1, the wheel speed WR of the driving wheel of the other side is driven according to the slip ratio in the traction control region as shown in FIG. 3. Speed (TW) or more, and the average speed of both drive wheels ( If greater than), the traction control unit 20 determines that the current road is a uniform road surface having the same left and right friction coefficient (S4). On the contrary, after the wheel speed WL of the driving wheel is restored by the control of the one side driving wheel WL and a predetermined time T1 has elapsed, the wheel speed WR of the counterpart driving wheel has a target driving wheel according to the slip ratio in the traction control region as shown in FIG. 4. Below the speed TW and the average speed of both drive wheels If smaller than), the traction control unit 20 determines that the current driving road is an asymmetric road surface with different left and right friction coefficients (S4).

When the current driving road is determined to be a uniform road surface (S4), the traction control unit 20 sets the traction control mode to engine output control (S5), and opens and closes the throttle valve and reduces the fuel injection amount through the engine output control unit 32. Alternatively, by lowering the output of the engine due to interruption, perception of the ignition timing (S6), the excessive excessive driving wheel slip is controlled at the slip ratio in the traction control region so that sufficient cornering force and driving force can be obtained.

In addition, if it is determined that the current driving road is an asymmetrical road surface (S4), the traction control unit 20 sets the traction control mode to drive wheel brake control (S5) and controls the braking force of each drive wheel through the brake control unit 31 (S6). The initial excessive driving wheel slip is controlled at the slip ratio in the traction control region so that sufficient cornering force and driving force can be obtained.

As described above, the present invention determines whether the current driving road is a uniform road surface or an asymmetric road surface at the time of controlling the initial acceleration of the vehicle and performs the engine output control or the driving wheel brake control accordingly, thereby improving the driving stability of the vehicle as well as the traction. The effect of control can be maximized.

Claims (3)

Calculating a target speed of the drive wheel for detecting the speed of the vehicle body during acceleration of the vehicle and controlling the slip rate in the traction control region; Detecting a speed of each driving wheel and determining a state of a current driving road by comparing the driving wheel target speed calculated in the step; And setting the traction control mode according to the state of the current driving road determined in the step to perform traction control. The method of claim 1, wherein the determination of the state of the current driving road in the step is determined that the wheel speed of the counterpart drive wheel after a predetermined time after the wheel slip is restored by the control of one drive wheel in which excessive slip has occurred, the drive wheel target speed calculated in the above step, both drive wheels The control mode determination method of the traction control system, characterized in that it is determined to be a uniform road surface if the average speed is greater than, and that the wheel speed of the opposing driving wheel is less than the target speed of the driving wheel, and is less than the average speed of both driving wheels. The method of claim 1 or 2, wherein the setting of the traction control mode in the step is to control the traction control by setting the engine output control mode when it is determined as the uniform road surface in the step, and by setting the drive wheel brake control mode when it is determined as an asymmetric road surface Control mode determination method of the traction control system, characterized in that the.