KR100250253B1 - Control device and its method of a power steering system - Google Patents

Abstract

PURPOSE: A power steering controller and its method controls steering optimally by judging the accurate road surface condition information by the changes of damping force and car height. CONSTITUTION: A power steering controller comprises a car speed sensor(100), a throttle position sensor(110), a first micro computer(120), a solenoid valve driving part(130), a car height sensor(150), an acceleration sensor(160) and a second micro computer(170). The throttle position sensor(110) detects the opening angle of a throttle valve. The first micro computer(120) determines car speed based on the signals inputted by the car speed sensor(100) and the throttle position sensor(110) and outputs current duty ratio to give steering force of a steering wheel appropriate to the car speed. The solenoid valve driving part(130) controls current to change the throttle area of a solenoid valve(140) by the duty ratio outputted by the first micro computer(120). The second micro computer(170) determines the road surface condition based on the signals inputted by the car height sensor(150) and the acceleration sensor(160), outputs current duty ratio to the solenoid valve driving part(130) to give steering force of the steering wheel appropriate to the road surface condition and communicates with the first micro computer(120). If the car drives on a rough road in low speed, The steering force of the steering wheel is adjusted to be heavy.

Description

Power steering control device and method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to power steering control of an automobile, and more particularly, to a vehicle power steering control apparatus and a method for controlling a power ratio of a steering wheel by determining a vehicle speed and a road surface condition.

In general, power steering is a hydraulic power source based on the hydraulic pressure of the hydraulic pump driven by the engine, as it can turn the car with light steering force.

As an example, a general power steering system is divided into a steering gear box 10, a dividing valve 20, and a solenoid valve 30 as shown in FIG. 1.

The steering gearbox 10 is coupled to the control valve shaft 12 at the upper end of the torsion bar 11 and coupled to the lower end with pins of the pinion shaft 13. A rotary valve 14 is coupled to the upper end of the pinion shaft 13 by a pin, and the steering wheel 15 is connected via the control valve shaft 12 and the steering shaft. Therefore, when the steering wheel 15 is rotated, the rotational force is transmitted to the pinion shaft 13 via the torsion bar 11 and the control valve shaft 12 so that the rack 17 engaged with the pinion 16 moves left and right. While rotating the wheels 18 and 19.

The dividing valve 20 is a valve for classifying oil discharged from the pump 21 into the rotary valve 14 side and the solenoid valve 30 side, and the rotary valve 14 side and the solenoid valve ( Even if the hydraulic pressure on the 30 side changes, the oil of constant flow is always supplied to the solenoid side.

The solenoid valve 30 adjusts the power of the steering wheel 15 by adjusting the oil amount by changing the throttle area according to the duty ratio of the current flowing through the coil.

The throttle area of the solenoid valve is controlled by the microcomputer 40 in accordance with the input signal of the vehicle speed sensor.

The electronically controlled power steering changes the hydraulic pressure of the power steering hydraulic control circuit according to the vehicle speed as the solenoid valve is controlled as shown in FIG. 2 (a), and the steering force is light at idle and low speed and reacts at low and medium speeds. Doing.

However, the conventional control method only controls the steering force in proportion to the speed of the vehicle, so there is a problem that the operation of the steering wheel becomes lighter when driving on an uneven road surface at low speed, which may cause an accident.

The present invention has been made to solve the above problems, and in particular, the vehicle steering control device to determine the optimum road condition information of the vehicle through the damping force and the garage height controlled in the electronically controlled suspension device to control the optimum handling and The purpose is to provide a method.

Steering wheel control device of the present invention for achieving this object is a vehicle speed sensor for detecting the vehicle speed, a throttle position sensor for detecting the opening angle of the throttle valve, and a vehicle speed based on the signal input from the vehicle speed sensor and the throttle position sensor And a first microcomputer for outputting a current duty ratio for giving steering force to the steering wheel corresponding to the vehicle speed, and a solenoid valve for controlling a current for changing the throttle area of the solenoid valve according to the duty ratio output from the microcomputer. A drive unit;

Determination of the road surface state of the road according to the height sensor to detect the position of the axle and the body according to the height of the vehicle body, the acceleration sensor for detecting the deceleration of the vehicle, and the signal input from the height sensor and the acceleration sensor In order to provide a steering wheel steering force according to the present invention, the current duty ratio is output to the solenoid valve driving unit and is characterized in that it is configured as a second microcom that can communicate with the first microcomputer.

In the steering wheel control method of the present invention, the road surface state determination step of determining the road surface state through the change of the height and the damping force, and when the road surface state is normal in the road state determination step, the solenoid by the duty ratio signal of the first microcomputer The valve is controlled, and when the road surface state is abnormal, the first microcomputer output is stopped and the solenoid valve is controlled by the duty ratio signal of the second microcomputer.

The road surface determination step is characterized in that it is determined as a bad road when the damping force changes in a high garage.

According to this configuration, the present invention detects the change of the garage and the damping force change when driving on the rough road rough road, and determines the rough road and reduces the current duty ratio applied to the solenoid valve to control the steering steering force heavily.

1 is a block diagram of a general power steering system;

2 is a current distribution diagram of the solenoid valve according to the vehicle speed, (a) is a conventional graph, (b) is a graph according to the present invention.

3 is a power steering control apparatus of the present invention.

Figure 4 is a flow chart for explaining the power steering control method of the present invention.

5 is a flowchart for explaining a road surface determination method of the present invention.

* Explanation of symbols for the main parts of the drawings

100: vehicle speed sensor 110: throttle position sensor

120: first microcomputer 130: solenoid valve drive unit

140: solenoid valve 150: height sensor

160: acceleration sensor 170: the second microcomputer

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

3 is a block circuit diagram for controlling the duty ratio of the current flowing in the solenoid valve according to the road surface condition and the change in the height, which is a vehicle speed sensor 100 for detecting a vehicle speed and a throttle position sensor 110 for detecting an opening angle of the throttle valve. And a first microcomputer for determining a vehicle speed based on a signal input from the vehicle speed sensor 100 and the throttle position sensor 110 and outputting a current duty ratio for giving steering force to the steering wheel corresponding to the vehicle speed. 120), the solenoid valve driver 130 for controlling the current for changing the throttle area of the solenoid valve 140 according to the duty ratio output from the microcomputer, the garage for detecting the position of the axle and the vehicle according to the height of the vehicle body The road surface state of the driving path may be determined based on a signal input from the sensor 150, the acceleration sensor 160 detecting the deceleration of the vehicle, and the height sensor 150 and the acceleration sensor 160. Is to impart a steering wheel steering force according to a road surface state, the output current duty ratio to the solenoid valve driver 130, and comprises a first microcomputer and a second microcomputer communicable 170.

The solenoid valve control method for controlling the steering force of the steering wheel of the present invention configured as described above will be described in detail with reference to FIGS. 4 and 5.

The present invention determines the road surface state based on the signal input to the height sensor 150 and the acceleration sensor 160 (S10-S30).

At this time, the road surface state determination method is determined as the abnormal road surface where the road surface is rough when the damping force increases in the state of the height "high" as shown in Figure 5, otherwise it is determined as normal road ( S31-S34).

In other words, when the vehicle speed is normally reduced on a normal road, the damping force decreases. On the contrary, the damping force increases when the humway or the bounding road is low, and the second microcomputer 170 determines whether the humway is based on this. do.

In the road surface determination method, if the road surface state is normal, the solenoid valve driving unit 130 is controlled by the duty ratio signal output from the first microcomputer 120 to the solenoid valve 140 as in the usual method. On the contrary, when the road surface state is abnormal, the first microcomputer 120 stops controlling the duty ratio and controls the solenoid valve driver 130 in the second microcomputer 170 (S40-S70). do.

At this time, it will be obvious that the first microcomputer 120 and the second microcomputer 170 should be able to communicate with each other.

Therefore, the present invention can provide optimal handling by heavily controlling the steering force of the steering wheel when driving the rough road at low speed.

As described above, the present invention controls the solenoid valve that controls the steering force of the steering wheel by classifying the road surface when driving on a normal road or a rough road, and when driving the rough road, the steering force of the steering wheel is heavy to the driver. This has the effect of making handling easier.

Claims (3)

Determining the vehicle speed based on signals input from the vehicle speed sensor for detecting the vehicle speed, the throttle position sensor for detecting the opening angle of the throttle valve, and the vehicle speed sensor and the throttle position sensor and providing steering force corresponding to the vehicle speed A first microcomputer for outputting a current duty ratio for the first microcomputer; a solenoid valve driving unit for controlling a current for changing the throttle area of the solenoid valve according to the duty ratio output from the microcomputer; and a position of the axle and the vehicle according to the height of the vehicle body The solenoid valve to determine the road surface condition of the driving path according to a signal input from the height sensor and the acceleration sensor, and to give a steering wheel steering force according to the road surface condition. A second microcomputer that outputs a current duty ratio to the driver and communicates with the first microcomputer A power steering control device according to claim. A power steering control method comprising vehicle speed determining means and road surface condition determining means, comprising: a road surface determination step of determining a road surface state through a change in a garage and a change in damping force, and when the road surface state is normal in the road surface determination step The solenoid valve is controlled by the duty ratio signal of the first microcomputer, and when the road surface state is abnormal, the first microcomputer output is stopped and the solenoid valve is controlled by the duty ratio signal of the second microcomputer. The power steering control method according to claim 2, wherein the road surface determination step is determined as a bad road when the damping force is changed in a state where the garage height is high.