KR950013088B1 - A method of steering control of vehicle - Google Patents

Abstract

The method is provided for controlling hydraulically the vehicle steering by regulating the fluid amount intaken to a hydraulic cylinder by means of controlling the current inputted into a solenoid according to the signals of both vehicle speed and steering angular velocity. It is characterized by calculating a transverse acceleration in an operation part of the control system and regulating the current inputted into the solenoid according to the operated transverse acceleration, the vehicle speed and the steering angular velocity.

Description

Steering Control Method of Vehicle

1 is a block diagram of a steering apparatus for a vehicle according to the present invention.

2 is a conceptual block diagram illustrating a steering control method of a vehicle according to the present invention.

3 is a flow rate change graph for various signals in the steering control method of the vehicle according to the present invention.

4 is a conceptual block diagram illustrating a conventional steering control method.

* Explanation of symbols for main parts of the drawings

10 flow control member 11 solenoid

20: control device 22: lateral acceleration calculation unit

50: hydraulic cylinder 60: vehicle speed detecting member

70: steering angle detection member 80: engine speed detection member

The present invention relates to a steering control method of an automobile, and more particularly to a steering control method of a hydraulic steering device.

In general, hydraulic steering devices are mainly used in small vehicles, and such steering devices are currently proposed and used in various forms.

In general, the hydraulic steering device is to reduce the steering reaction during low-speed driving and parking operation. Looking at the operation, when the driver rotates the steering wheel in a predetermined direction as needed while driving, the rotary valve rotates the orifice. At the same time as the pressure is generated in the oil supplied from the oil pump is supplied with hydraulic pressure to one side of the hydraulic cylinder.

As a result, the supplied hydraulic pressure causes pressure in the steering direction according to the driver's steering operation, thereby reducing the steering reaction force.

However, the steering apparatus of such a configuration is mainly designed to reduce the steering reaction when driving at low speed, and has a problem that the stability of adjustment is extremely degraded at the high speed of the vehicle.

On the other hand, while attempting to solve the above problems by adjusting the flow rate supplied to the hydraulic cylinder, in this case, when the driver suddenly rotates the steering wheel in response to a sudden accident during high-speed driving with a low supply flow rate to the hydraulic cylinder, the hydraulic cylinder Instantaneous vacuum occurs. Therefore, the catch-up phenomenon caused by this causes the driver to lose a sense of steering momentarily, causing various accidents, such as causing a bad effect on the safety of the vehicle.

Therefore, in recent years, in order to solve the problems of the conventional apparatus as described above, a steering apparatus for sensing the speed of the vehicle speed and the steering angle and controlling the flow rate in the hydraulic cylinder based on the detected speed has been developed. An example is that of the configuration shown in FIG.

As can be seen from the figure, the steering device of this type has a hydraulic cylinder 50 mounted on the tie rod 40 that directly transfers the steering force transmitted from the steering wheel to both wheels, and is driven by power generation of the vehicle body. It is interposed between the oil pump 110 and the hydraulic cylinder 50 and the oil pump 110 to supply an appropriate amount of flow rate to the cylinder, and cooperates with the steering shaft 100 based on the left and right steering as needed. It is provided with a rotary valve 90 for selectively distributing and supplying hydraulic pressure to both sides of the.

In addition, the conventional steering apparatus of the above-described type is installed between both sides of the hydraulic cylinder 50, the flow control member 10 for providing a flow path on both sides, and receives the operation information from the vehicle speed and steering angle speed sensing member flow control member The control device 20 for controlling the intermittent control is further provided. Moreover, the hydraulic cylinder 50 is provided with two division chambers 51 and 52 which are separated to both sides. This invention relates to the control apparatus which intermittently controls the said flow control material which provides a flow path to both sides of a hydraulic cylinder substantially.

Next, a conventional steering control method employed in a typical steering apparatus having the configuration as described above will be described. 4 is a conceptual block diagram illustrating a conventional steering control method, in which the control device 20 for performing steering control is a detection signal from an engine speed detecting member, as shown in the figure. Then, the steering signal of the vehicle is controlled by inputting a detection signal from the vehicle speed detecting member and the steering angular velocity detecting member.

Therefore, according to the conventional steering control method, the steering force is adjusted by controlling the solenoid conduction current based on the detection signal from the vehicle speed sensing member, and the catch is a problem when driving at high speed by measuring the steering angle speed member. Eliminate the phenomenon.

However, when only the increase in flow rate due to the steering angular velocity is considered in order to control the catch-up phenomenon at high speed, excessive steering occurs, which causes a phenomenon that is dangerous to the stability of the vehicle at high speed.

Accordingly, an object of the present invention is to provide a steering control method for a vehicle capable of overcoming the above-mentioned problems of the prior art and at the same time to prevent excessive steering occurring during rapid rotation of the steering wheel.

In order to achieve the above object, the present invention, based on the vehicle speed signal and the steering angular velocity signal from each sensing member disposed in a predetermined portion of the vehicle control the conduction current to the solenoid through the current control means in the transverse acceleration calculation unit in the control device In the steering control method of the vehicle to control the steering of the vehicle by adjusting the flow rate flowing into the hydraulic cylinder, the lateral acceleration is calculated based on the vehicle speed signal and the steering angular velocity signal, and the calculated lateral acceleration, vehicle speed and steering angle speed signal According to the present invention, there is provided a steering control method for a vehicle, characterized by controlling an energized current to a solenoid.

Other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

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

2 is a conceptual block diagram illustrating a steering control method for a vehicle according to the present invention. The constituent member denoted by reference numeral 20 in the drawing is a control device corresponding to the same reference numeral shown in FIG. 1, and is configured to input an engine speed signal, a vehicle speed signal, and a steering angular speed signal. Accordingly, as shown in FIG. 1, when the detection signals are input from the vehicle speed and steering angle speed sensing members 60 and 70, the control device 20 uses the lateral acceleration computing unit 22 built in on the basis of these signals. By calculating the vehicle driving information and controlling the energizing current to the solenoid 11 in accordance with the calculation result, the inflow flow rate into the hydraulic cylinder 50 shown in FIG. In addition, the engine speed signal input to the control device 20 is utilized to check for an abnormality of the vehicle speed detecting member as in the above-described prior art.

3 is a graph showing a flow rate variation for various signals, i.e., Q vehicle speed, Q 'angular velocity and Q "lateral acceleration, which are obtained based on these signals in the vehicle steering control method according to the present invention. With reference to the steering control method according to the invention in detail.

Q vehicle speed as shown in the figure is used to control (decrease or increase) the flow rate according to the speed of the vehicle, Q 'angular speed is the amount of movement of the hydraulic cylinder (reference numeral 50 in FIG. 1) as the steering wheel is moved. It is used to eliminate the catchup phenomenon caused when the flow rate cannot be compensated for the volume change instantaneously. That is, the flow rate is linearly increased according to the Q 'angular velocity by supplying a compensated flow rate for the steered steering (when a fast steering angular velocity is input to the controller 2 °). If this is expressed as an expression, it is expressed as Equation (1) below.

Q 'angular velocity = K angular velocity x W... … … … … … … … … … … … … … … … (One)

Here, K angular velocity represents steering angular velocity gain and W represents steering angular velocity, respectively.

Therefore, when the driver sharply steers the steering wheel due to an unexpected sudden curve or unexpected condition, that is, when the steering is performed at high speed and suddenly, it is necessary to reduce excessive steering accordingly. The present invention is directed to a vehicle speed signal and a steering angle speed signal from the vehicle speed and steering angle speed sensing members 60 and 70 shown in FIG. 1 through the control device 20 in order to prevent excessive steering occurring under such a situation. The lateral acceleration is calculated based on this, and the flow rate into the hydraulic cylinder (reference numeral 50 in FIG. 1) is adjusted by controlling the energizing current to the solenoid 11 based on the calculated lateral acceleration, the vehicle speed and the steering angle signal.

The lateral acceleration Q ", which is a reduced flow rate according to the lateral acceleration calculated based on the vehicle speed and the steering angular velocity signal, can be expressed by the following Equation (2).

Q "Lateral acceleration = Ka × A ………………………………………………………… (2)

Here, Ka represents the lateral acceleration gain and A represents the lateral acceleration, respectively.

However, when using a separate sensor for the measurement of the lateral acceleration as described above, the manufacturing cost of the overall steering control system is increased. Therefore, in the present invention, the lateral acceleration is approximated and used as the product of the vehicle speed and the steering angular velocity. If this is expressed as equation, it is as following (3).

Q "Lateral acceleration = Ka x V x W ………………………………………………… (3)

Here Ka is the lateral acceleration gain, V is the vehicle speed, and W is the steering angular velocity, respectively.

Accordingly, the controller 20 adjusts the energizing current to the solenoid 11 so that the flow rate Q "'cylinder supplied to the hydraulic cylinder 50 becomes Q"' cylinder = Q vehicle speed + Q'angular velocity-Q "lateral acceleration. The optimum flow rate suitable for the driving state of the vehicle is supplied to the hydraulic cylinder to prevent excessive steering occurring during rapid turning of the steering wheel.

As described above, according to the present invention, the lateral acceleration is calculated by the lateral acceleration calculation unit in the control device based on the vehicle speed signal and the steering angular velocity signal from the sensing member disposed in the predetermined portion of the vehicle, and the hydraulic pressure is calculated based on these three values. By controlling the inflow current by adjusting the flow rate into the cylinder, excessive steering caused during steep rotation of the steering wheel during high-speed driving can be effectively prevented.

Claims (1)

A vehicle that controls the steering of the vehicle by controlling the flow rate flowing into the hydraulic cylinder by controlling the energizing current to the solenoid through the current control means based on the vehicle speed signal and the steering angular velocity signal from each sensing member disposed in the predetermined portion of the vehicle. A steering control method according to claim 1, wherein the lateral acceleration calculation unit calculates lateral acceleration based on the vehicle speed signal and the steering angular velocity signal, and energizes the solenoid based on the calculated lateral acceleration and the vehicle speed and steering angular velocity signal. Steering control method for a vehicle, characterized in that for controlling the current.