KR20090011730A - Control method for electronics stability program in a vehicle - Google Patents

Abstract

A vehicle posture control method is provided that the rear and front wheel actuating ratio calculated and set up in advance are controlled through the electronic 4 wheel driving system based on the front wheel drive. A vehicle posture control method comprises following steps: if the vehicles comes under one situation among braking, accelerating, oversteering and understeering a step for calculating rear and front wheel actuating ratio which are set up in advance in order to correspond to the situation; a step controlling calculated rear and front wheel actuating ratio through the electronic four wheel driving system of the front wheel drive base.

Description

CONTROL METHOD FOR ELECTRONICS STABILITY PROGRAM IN A VEHICLE}

1 is a block diagram illustrating a system configuration of a vehicle attitude control apparatus, an engine controller, and a 4WD controller according to an exemplary embodiment of the present invention.

2 is a view for explaining whether the vehicle is understeer or oversteer using the difference between the reference yaw rate calculated from the vehicle model and the actual yaw rate of the vehicle.

FIG. 3 is a table for explaining a driving force distribution relationship between front wheels and rear wheels for each vehicle behavior by using an electronic four-wheel drive system based on front wheel driving for each vehicle behavior.

4 is a control flowchart of a vehicle attitude control method according to an embodiment of the present invention.

* Description of the symbols for the main functions of the drawings *

S100: Braking judgment step S110: ABS control situation judgment step

S140: Acceleration determination step S150: TCS control situation determination step

S170: Oversteer Situation Judgment Step S180: Understeer Situation Judgment Step

The present invention relates to a vehicle attitude control method, and more particularly, in the vehicle equipped with the electronic 4WD system and the ESP system, the driving torque of the front wheel and the rear wheel is appropriately distributed according to the vehicle behavior to optimize various driving modes. It relates to a vehicle attitude control method that can implement the driving ratio of.

In general, the vehicle attitude control device, called the ESPTRONIC STABILITY PROGRAM SYSTEM, is a device for securing the vehicle's driving stability. An excessive plow of the vehicle (the vehicle is pushed outward from the desired driving course) (understeer) Prevents spin-out (oversteer), which results in a sharp decrease in turning radius due to an undesired increase in the vehicle's turning speed. To this end, a method of compensating the unwanted vehicle turning moment by controlling the braking force and the driving force is used.

There is a difference in the behavior of the vehicle in the case of all-wheel drive (FWD) and four-wheel drive (4WD) by the characteristics of the drive line (Drive line), each driving method has advantages and disadvantages for the various driving modes.

In the oscillation acceleration situation, the acceleration performance of a 4WD vehicle is usually superior, and the acceleration performance of an FWD vehicle is inferior. In braking situations, the braking performance of a FWD vehicle usually prevails, and the braking performance of a 4WD vehicle is poor. The performance of the FWD driving method prevails in the case of a vehicle in which the basic characteristics of the vehicle show an oversteer tendency while turning, and the 4WD method in the case of a vehicle in which the basic characteristic of the vehicle exhibits an oversteering tendency in the turning situation The turning performance is inferior.

As described above, the vehicle equipped with the electronic 4WD system and the ESP system (Electronic Stability Program system) can appropriately distribute the driving torque of the front wheel and the rear wheel according to the vehicle behavior to implement the optimum driving ratio in various driving modes. There is a need.

An object of the present invention is to distribute the driving torque of the front wheel and the rear wheel according to the vehicle behavior according to various driving conditions in the vehicle equipped with the electronic 4WD system and ESP system according to the vehicle driving force distribution system that can realize the optimal driving ratio in various driving modes To provide.

Vehicle attitude control method of the present invention for achieving the above object is the four wheel speed sensor, yaw rate sensor, lateral acceleration sensor, steering angle sensor, the master is installed with an electronic four-wheel drive system based on the front wheel drive Sensing the driving information of the vehicle by using the cylinder pressure sensor, controlling the pressure of each wheel by using the hydraulic modulator, and detecting the engine information by communicating with the engine block through the can communication, the electronic 4WD through the can communication A vehicle attitude control method for controlling the driving ratio of the front and rear wheels in communication with a system, wherein the vehicle is in any one of braking, acceleration, oversteer or understeer conditions, And can communicate with the all-wheel drive-based electronic four-wheel drive system to communicate with the all-wheel drive-based electronic four-wheel drive system. And controlling the calculated front and rear wheel drive ratios.

If the driver is willing to brake the vehicle and the vehicle is not in ABS control, the driving ratio of the front and rear wheels is controlled to 100: 0 in 100 msec, and if the driver is willing to brake and the ABS is controlled, the driving ratio of the front and rear wheels Is controlled to 100: 0 in 20 msec, and the driver's driving ratio of the front and rear wheels is controlled to 60:40 in 100 msec, unless the driver is willing to accelerate and TCS is controlled. In the case of a steer situation, the driving ratio of the front wheel and the rear wheel is controlled to the driving ratio required by the ESP system within 100 msec.

Stopping the driving ratio control of the front and rear wheels when the vehicle speed of the vehicle is outside the preset speed range to the stable region, the driver stops braking or acceleration, or the vehicle leaves the oversteer or understeer situation. Characterized in that.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 is a block diagram illustrating a system configuration of a vehicle attitude control apparatus, an engine controller, and a 4WD controller according to an exemplary embodiment of the present invention. 2 is a view for explaining whether the vehicle is understeer or oversteer using the difference between the reference yaw rate calculated from the vehicle model and the actual yaw rate of the vehicle. FIG. 3 is a table for explaining a driving force distribution relationship between front wheels and rear wheels for each vehicle behavior by using an electronic four-wheel drive system based on front wheel driving for each vehicle behavior.

1 to 3, the vehicle equipped with the electronic 4WD system and the ESP system appropriately distributes the driving torque of the front wheel and the rear wheel according to the vehicle behavior, thereby realizing an optimal driving ratio in various driving modes.

This ESP add-on is called Torque On Demand (hereinafter referred to as TOD) control. As shown in FIG. 1, when the ESP system requests an optimal driving ratio through CAN communication, the TOD control may implement the driving ratio requested by the ESP within a predetermined time according to the electronic 4WD electronic control unit (ECU). Allocate the driving force so that it can

In general, a vehicle equipped with an electronic 4WD system maintains FWD or RWD performance without control of the electronic 4WD. The present invention relates to an FWD Based electronic 4WD system, wherein the vehicle is controlled to transmit the driving force requested by the ESP system to the rear axle as needed in the FWD state, which is a basic state, so that the driving force distribution ratio between the target front wheel and the rear wheel ( Drive ratio).

Entry conditions of TOD control are as follows.

First, when it is determined that the driver is performing braking through the brake light switch information and the master cylinder pressure sensor value, the TOD control is started.

In addition, it is determined that the driver is accelerating through the main throttle position value, which detects the position of the accelerator pedal, and accordingly, the TCS improves the acceleration performance by preventing the slip of the wheel during acceleration of the vehicle such as a quick start. If control by (Traction Control System) is being performed, start TOD control.

In addition, as shown in FIG. 2, the driver is controlled from the vehicle model by using steering sensor information, yaw and lateral acceleration sensor information, and wheel speed sensor information. TOD control is started when the difference between the target reference yaw rate and the target yaw rate actually generated in the vehicle is calculated and the oversteer situation exceeds the yaw rate difference "+ ?? r Threshold".

In the case where the TOD control is started under the above conditions, when the vehicle is a front wheel based (FWD Based) electronic 4WD vehicle, the driving ratio of the front wheel and the rear wheel is controlled according to the behavior of the vehicle as shown in FIG. 3.

That is, as shown in FIG. 4, if there is no ABS (Antilock brake system) control situation when the driver is willing to brake, the driving ratio of the front wheel and the rear wheel is made 100: 0 in 100 msec through the TOD control. (S100, S110, S120, S200).

In addition, in the ABS control situation when the driver is willing to brake, the driving ratio of the front wheel and the rear wheel is made 100: 0 in 20 msec through the TOD control (S100, S110, S130, and S200).

In addition, when there is a driver's willingness to accelerate, the TOD control makes the driving ratio of the front wheel and the rear wheel 60:40 in 100 msec (S100, S140, S150, S200).

In addition, if the behavior of the vehicle is determined to be an oversteer situation, the driving ratio of the front wheel and the rear wheel is made to the driving ratio required by the ESP system within 100 msec through the TOD control, and if the behavior of the vehicle is determined to be an understeer situation, the TOD control is performed. The driving ratio of the front wheel and the rear wheel is made to the driving ratio required by the ESP within 100 msec (S100, S140, S170, S180, S190, S200).

When the TOD control is performed in the above manner, the TOD control is terminated in the following situations.

If the vehicle speed is out of the preset speed range to the stable area, the driver's braking will disappear when the TOD control is started in braking situation, or the driver's acceleration will disappear when TOD control is started during TCS control in the acceleration situation. If the TCS control ends or the yaw rate difference of the vehicle enters the stable area and is out of the oversteer or understeer situation, the TOD control ends.

As described in detail above, according to the present invention, in the vehicle equipped with the electronic 4WD system and the ESP system, by appropriately distributing the drive torque of the front wheel and the rear wheel according to the vehicle behavior in accordance with various driving conditions, the optimum driving ratio in various driving modes There is an effect that can be implemented.

Claims (3)

Four wheel speed sensors equipped with an all-wheel drive electronic four-wheel drive system, yaw rate sensor, lateral acceleration sensor, steering angle sensor, and master cylinder pressure sensor detect the vehicle's driving information, Vehicle posture control to control the pressure of each wheel by using the modulate, detect engine information by communicating with the engine block through can communication, and control the driving ratio of the front and rear wheels by communicating with the electronic 4WD system through can communication. In the method, If the vehicle corresponds to any one of braking, acceleration, oversteer or understeer conditions, the front and rear wheel drive ratios preset to correspond to the situation are calculated, And can communicating with the all-wheel drive-based electronic four-wheel drive system to control the calculated front and rear wheel drive ratios through the all-wheel drive-based electronic four-wheel drive system. The method of claim 1, wherein if the driver has the braking intention to the vehicle and is not in the ABS control situation, the driving ratio of the front wheel and the rear wheel is controlled to 100: 0 in 100 msec, and if the driver has the braking intention and the ABS control situation, The driving ratio of the front and rear wheels is controlled to 100: 0 in 20 msec, and the driving ratio of the front and rear wheels is controlled to 60:40 in 100 msec unless the driver is willing to accelerate and is not in TCS control. If the behavior is an oversteer or understeer situation, controlling the drive ratio of the front and rear wheels to the drive ratio required by the ESP system in 100 msec. The driving ratio of the front wheel and the rear wheel according to claim 1, wherein when the vehicle speed of the vehicle is out of a preset speed range to the stable region, the driver stops braking or accelerating, or the vehicle leaves the oversteer or understeer situation. Vehicle attitude control method to stop the control.

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