KR20030008081A - Rear Wheel Phase Converting Method of 4Wheel Steering Vehicle and System thereof - Google Patents

Abstract

PURPOSE: A transforming method of the phase in rear wheels and its system are provided to reduce the bump against an object and to improve the parking property and the stability by controlling the phase for the steering angle of rear wheels. CONSTITUTION: A speed sensor(18) detects the speed of a vehicle. A steering angle sensor of front wheels(17) detects the steering status of the front wheels by a steering wheel(16). Object sensors(21,22) detect a distance from an object by installing the left and the right of the vehicle. A control unit(20) outputs control signals by deciding the detected signals from the speed sensor, the steering angle sensor of front wheels and object sensors. An electromotive steering device(26) controls the steering of rear wheels by the control signals from the control unit. An instrument panel(24) displays the steering of the electromotive steering device visually and acoustically when the electromotive steering device is steered as the same phase as the steering angle of the front wheels in a slow area. The phase of the rear wheels are transformed to improve the parking property and the stability in the slow area.

Description

Rear wheel phase converting method of 4 wheel steering vehicle and system

The present invention relates to a rear wheel phase shifting method and system thereof for a four-wheel steering vehicle, and more particularly, to a method and system for converting a phase of a rear wheel during rotation for parkingability and stability in a low speed region of a four-wheel steering vehicle. It is about.

Generally, there are many kinds of automobiles, and they are classified according to their purpose of use, type of prime mover, or structure or shape of the vehicle body. In other words, classification by engine and energy source, classification by engine installation location, classification by driving method, classification by number of wheels, classification by shape of vehicle body, classification by use, classification by law and international sports law It is divided into classification by.

In particular, it is divided into front wheel (front wheel drive, front wheel drive), rear wheel (rear wheel drive, rear wheel drive), front wheel (all wheel drive, all wheel drive). In addition, when the engine installation location and driving method are combined, the front engine rear wheel drive (FR), the front engine front wheel drive (FF) and the rear engine rear wheel drive method (Rear Engine Rear) Wheel Drive, RR).

Conventionally, in the case of a front wheel drive system, that is, a four-wheel steering vehicle, referring to the drawing showing the steering state at the low speed and the high speed of FIG. In the case of the right turning direction, in the low speed region (v≤v ₀ ; v ₀ is the set reference speed), to improve the heading performance (the vehicle moves in the direction intended by the driver). The rear wheels are steered in the opposite direction (δ _r = -kδ _f ) from the front wheel steering angle δ _f , and in the high speed range (v> v ₀ ; v ₀ is the set reference speed), the front wheel steering angle ( a rear wheel as δ _f) in the same direction (δ _r = kδ _f) it is steering.

However, when there is an obstacle such as another vehicle, a road surface, or a wall near the outside of the turning radius of the vehicle when the vehicle is started or parked, the rear wheel has an inverse phase with the front wheel steering angle. There was a problem that is likely to come in contact with the obstacle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. When an object is detected at a predetermined distance from an object detecting means mounted on the side of a vehicle when starting or parking in a low speed region of a four-wheel steering vehicle, the rear wheel steering angle is adjusted by adjusting the phase. It is an object of the present invention to provide a rear wheel phase shifting method of a four-wheel steering vehicle for reducing the possibility of contact and improving parking performance and safety.

Another object of the present invention is to provide a rear wheel phase shifting system of a four-wheel steering vehicle for automatically controlling the steering angle of the rear wheel according to a condition by determining and comparing signals detected from a plurality of sensing means mounted on the vehicle. .

1 is an explanatory diagram schematically showing a steering state at a low speed and a high speed of a conventional four-wheel steering vehicle;

2 is a block diagram of a rear wheel phase shift system of a four-wheel steering vehicle according to the present invention;

3 is an explanatory diagram schematically showing a steering state at low and high speeds of a four-wheel steering vehicle according to the present invention;

4 is a flow chart showing the rear wheel phase shift of a four-wheel steering vehicle according to the present invention.

♣ Explanation of symbols for main part of drawing ♣

10, 11: front wheels 12, 13: rear wheels

15: front wheel steering 16: steering wheel

18: vehicle speed detecting means 20: control means

21, 22: object detection means 24: instrument panel

26: electric steering system

In order to achieve the above object, the present invention provides a vehicle speed signal v detected by the vehicle speed detecting means, a front wheel steering angle signal δ _f detected by the front wheel steering angle detecting means, and a distance signal d between the object detected by the object detecting means. The first step of the control means recognizes; A second step of determining whether the vehicle speed signal v recognized by the control means is less than or equal to a set reference speed v ₀ ; A third step of determining whether the front wheel steering angle signal is clockwise or counterclockwise when the vehicle speed signal v recognized in the second step is less than or equal to the set reference speed v ₀ ; A fourth step of determining whether a collision distance with an object present on the left or right is within a set distance after the determination of the front wheel steering angle signal in the third step; A fifth step of converting and outputting the same phase signal as the phase of the front wheel when the distance is within the collision distance with the object in the fourth step or more than the reference speed set in the second step; A sixth step of converting and outputting a phase signal opposite to the phase of the front wheel if it is not within a collision distance with the object in the fourth step; A seventh step of driving the electric steering apparatus for steering the rear wheels with the phase signal of the control means output from the fifth and sixth steps; And an eighth step of continuously monitoring the driving state of the vehicle.

In addition, the present invention is a vehicle speed detection means for detecting the speed of the vehicle, a front wheel steering angle detection means for detecting the steering state of the front wheel according to the driving of the steering wheel, and at least one mounted on the left and right sides of the vehicle, respectively An object sensing means for sensing a distance from the vehicle, a control means for determining a sensing signal input from the vehicle speed sensing means, a front wheel steering angle sensing means, and an object sensing means, and outputting a control signal to the control signal of the control means; Provided is a rear wheel phase shifting system of a four-wheel steering vehicle including an electric steering device for controlling steering of a rear wheel.

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

2 is a block diagram of a rear wheel phase shifting system of a four-wheel steering vehicle according to the present invention.

The vehicle speed detecting means 18 is for detecting the speed of the vehicle 1 and outputting it as an electrical signal. The vehicle speed detecting means 18 is mounted on the speedometer driven gear of the transmission, and the output gear rotation speed of the transmission is provided. A sensor for inputting a pulse signal proportional to (vehicle speed) to the control means. It is composed of two systems, main and sub, to ensure operation reliability.

The front wheel steering angle detecting unit 17 detects a steering state of the front wheels 10 and 11 according to the driving of the steering wheel 16. When the driver rotates the steering wheel 16 to the left or right to rotate, It detects the driving angle and outputs an electrical signal.

One or more object detecting means (21, 22) are mounted on the left and right sides of the vehicle, that is, at the left or right side of the front bumper and / or immediately behind the front wheel to detect a distance from an obstacle and output a detection signal. For example, the size of the signal or the period of the signal varies depending on the sensing distance from the obstacle.

The control means 20 is for outputting a control signal by determining respective detection signals inputted from the vehicle speed detecting means 18, the front wheel steering angle detecting means 17, and the object detecting means 21 and 22. It is a control unit for driving and overall control.

The electric steering device 26 is for controlling steering of the rear wheels 12 and 13 by the control signal of the control means 20. The rear wheel (eg, by the electric motor and the rack gear) according to the control signal of the control means 20. 12, 13) to control the steering angle.

The instrument panel 24 is for visually and audibly displaying the electric steering device 26 when the electric steering device 26 is steered in the same phase as the steering angle of the front wheels 10 and 11 in the low speed region. , 11) to flash a lamp including a logo for indicating steering in the same phase as that of 11), and to output a sound having a predetermined period and frequency.

In addition, the steering method of the front wheel steering device 15 of the present invention is controlled by converting the steering state of the steering wheel 16 to hydraulic pressure, and the steering device of the rear wheels 12, 13 is preferably applied to the electric steering device. In addition, the steering angles of the front wheels 10 and 11 and the rear wheels 12 and 13 may be controlled by applying the electric motor to the front wheel steering device 15 and the electric steering device 26 in the same manner.

The rear wheel phase shifting method of the four-wheel steering vehicle using the system of the present invention configured as described above will be described in detail with reference to the explanatory diagram of FIG. 3 and the flowchart of FIG. 4.

That is, according to the present invention, the steering angle of the rear wheels 12 and 13 in the high speed range is not only converted to the same steering angle as the front wheels 10 and 11, but also the rear wheel when the object, that is, the obstacle is located in the rotational direction in the low speed area. The steering angle of (12, 13) is for causing the phase to be converted to the same steering angle as the front wheels (10, 11).

First, the front wheel steering angle signal detected by the vehicle speed signal v and the front wheel steering angle detection means (17) detected by the vehicle speed detecting means 18 for during running of the vehicle in the step 1 (S10) δ _f and object detection means (21, 22) The control means 20 recognizes the distance signal d from the detected obstacle. This is for detecting the speed of the vehicle, the steering angle of the front wheels 10 and 11, and the position of an object (obstacle) with respect to the rotation direction.

In the second step S11, it is determined whether the vehicle speed signal v recognized by the control means 20 is less than or equal to the set reference speed v ₀ . In other words, it is basically to determine whether the speed of the vehicle is a high speed region or a low speed region. In the low speed area, it will be less than or equal to the set reference speed, and in the high speed area, it will be greater than the set reference speed.

In the third step S12-S14, when the vehicle speed signal v recognized in the second step is a low speed region equal to or less than the set reference speed v ₀ , whether the front wheel steering angle signal is clockwise (δ _f = CW) or counterclockwise. It is determined whether the direction (δ _f = CCW, Counter Clock Wise). At this time, in step S13, when the front wheel steering angle is clockwise CW, that is, steering to the right, the object detecting means 21 mounted on the left side of the vehicle is operated, and in step S14, the front wheel steering angle is counterclockwise ( CCW), i.e. steering to the left, activates the object detecting means 22 mounted on the right side of the vehicle.

Therefore, after the determination of the front wheel steering angle signal in the third step (S12-S14), when the object detection means (21, 22) of the left or right in the fourth step (S15) is left or right, that is, an obstacle exists It is determined whether the collision distance with the obstacle is within the set distance (d≤d ₀ , d ₀ is the set reference distance).

As described above, when the driving distance is within the collision distance with the obstacle in the fourth step S15 or is equal to or higher than the reference speed set in the second step S11 (high speed area), the front wheels 10 and 11 are moved in the fifth step S16-S17. A phase signal δ _r = kδ _f equal to the phase δ _r = kδ _f of the output signal is output to the electric steering device 26 that drives the rear wheels 12 and 13. At this time, the control means 20 in the fifth step (S17) through the instrument panel 24 to periodically flash the lamp having the form of a predetermined logo in the abnormal conversion state of the low speed region to give a visual effect, At the same time it flashes and outputs an alarm of a certain frequency, which calls attention to the driver.

However, in the sixth step (S18), if not within the collision distance with the obstacle in the fourth step (S15), the phase signal (δ _r = opposite to the phase (δ _r = kδ _f ) of the front wheels 10, 11 -Kδ _f ) to output it.

Thus, the rear wheel 12 using the electric motor and the rack gear mounted as the phase signal of the control means 20 output from the fifth step (S16-S17) and the sixth step (S18) in the seventh step (S19). And 13) are steered at a predetermined steering angle.

The same as the direction of the front wheels 10 and 11 which are steered when there is an object (obstacle) outside the direction of rotation of the vehicle while the vehicle is traveling in the low speed region through the second step S11 to the seventh step S19. By driving the rear wheels (12, 13) in the direction to avoid collision with the object.

Finally, after sufficient rotation is made without collision with the object, the driving state of the vehicle is continuously monitored in the eighth step S20 to repeat the second step S11 to the seventh step S19. To be able.

As described above, the present invention is applied to a four-wheel steering vehicle capable of driving the front wheel, for example, a special vehicle such as a forklift or a general passenger car, and determines the steering state of the front wheel in a low speed region of the vehicle to determine the rear wheel according to the presence or absence of an obstacle. It is to be able to steer in the same direction or in the opposite direction with the bar, in consideration of the present invention will be able to be sufficiently changed, converted, substituted and replaced, not limited to the above.

As described above, the method and system for rear wheel phase shifting of a four-wheel steering vehicle according to the present invention are within a reference speed set by a vehicle from a vehicle speed detecting means, and detect a steering state in a left or right direction from a front wheel steering angle detecting means, and corresponding directions After the control means detects whether the object is within the radius of rotation and compares it with the set value, the steering of the rear wheels is steered in the same or opposite direction as the front wheels. By preventing contact, it is possible to prevent safety accidents in advance, and there is an effect of improving parkingability and stability by increasing the function of the four-wheel steering vehicle.

Claims (3)

A first step of the control means recognizing a distance signal d between the vehicle speed signal v detected by the vehicle speed detecting means and the front wheel steering angle signal δ _f detected by the front wheel steering angle detecting means and the obstacle detected by the object detecting means while the vehicle is running; A second step of determining whether the vehicle speed signal v recognized by the control means is less than or equal to a set reference speed v ₀ ; A third step of determining whether the front wheel steering angle signal is clockwise or counterclockwise when the vehicle speed signal v recognized in the second step is less than or equal to the set reference speed v ₀ ; A fourth step of determining whether the collision distance with the obstacle existing on the left or the right is within a set distance after the determination of the front wheel steering angle signal in the third step; A fifth step of converting and outputting the same phase signal as the phase of the front wheel when it is within the collision distance with the obstacle in the fourth step or more than the reference speed set in the second step; A sixth step of converting and outputting a phase signal opposite to the phase of the front wheel if it is not within a collision distance with the obstacle in the fourth step; A seventh step of driving the electric steering apparatus for steering the rear wheels with the phase signal of the control means output from the fifth and sixth steps; And And a eighth step of continuously monitoring a driving state of the vehicle. The method of claim 1, wherein in the fifth step, the rear wheel phase shifting method of the four-wheel steering vehicle comprises converting and outputting the same phase signal as the phase of the front wheel and visually and acoustically displaying it through the instrument panel. Vehicle speed detecting means for detecting a speed of the vehicle; Front wheel steering angle detection means for detecting a steering state of the front wheel according to the driving of the steering wheel, One or more object detection means mounted on the left and right sides of the vehicle to detect a distance from an obstacle; Control means for determining a detection signal input from the vehicle speed detecting means, the front wheel steering angle detecting means, and the object detecting means and outputting a control signal; An electric steering device for controlling steering of the rear wheels with a control signal of the control means; And an instrument panel for visually and audibly displaying the electric steering device when the electric steering device is steered in the same phase as the steering angle of the front wheel in the low speed region.