KR102004344B1 - Steering control device and method thereof - Google Patents

Abstract

The present invention relates to a steering control apparatus and method thereof, and more particularly, to a steering control apparatus and method thereof, which includes an image pickup apparatus that is mounted on a vehicle and outputs an image of the surroundings of the vehicle and includes a plurality of cameras; An obstacle detecting unit for detecting an obstacle around the vehicle; A contact angle calculation unit for calculating a contact angle at which the wheel should be rotated to contact the obstacle by using the image when an obstacle is detected in the obstacle detection unit; And a steering control section for reducing an assist current value provided to the steering motor before a predetermined angle to reach the contact angle. As a result, an excessive load is generated in the steering motor, the battery, and the related parts, thereby preventing the service life and the durability from deteriorating.

Description

STEERING CONTROL DEVICE AND METHOD THEREOF BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The embodiments relate to a steering control apparatus and method.

Generally, a vehicle is provided with an electronic power steering (EPS) so as to easily steer the steering wheel, and the EPS assists the steering force of the driver by using the turning force of the steering motor.

The EPS includes an electronic control unit (ECU) that controls the steering motor driving when the steering wheel is steered. The ECU receives a signal from a steering angle sensor, a torque sensor, a vehicle speed sensor, an engine speed sensor, And provides it to the steering motor to adjust the steering feeling of the steering wheel.

On the other hand, when the wheels of the vehicle come into contact with the curb or obstacle during driving, the torque sensed by the torque sensor increases and the steering angle speed sensed by the steering angle sensor decreases, as shown in FIG. In this case, the ECU determines that the wheels are in contact with the curb or the obstacle when the torque is equal to or greater than a preset threshold value and the steering angle velocity is constant or less for a preset time, reduces the assist current with a certain gradient, So that a minimum assist current is provided.

However, if the assist current is reduced by the torque and the steering angle velocity after the wheels come into contact with the curb or the obstacle, the steering motor will not need more than the necessary time (t) until the wheel contacts the curb or obstacle and reduces the assist current An assist current is provided. As a result, the steering motor is overloaded, and the durability of the steering motor as well as the battery and related electronic parts is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a steering control device and a control method thereof, which can prevent an overload from being applied to a steering motor, a battery and related electronic components by controlling an assist current in anticipation of a curb or an obstacle coming into contact with a wheel A steering control device and a control method thereof.

The above-described object is achieved by an image pickup apparatus comprising: an image pickup device provided in a vehicle and outputting an image of the surroundings of the vehicle; An obstacle detection unit for detecting an obstacle around the vehicle; A contact angle calculating unit for calculating a contact angle at which the wheel should be rotated to contact the obstacle by using the image when the obstacle detecting unit detects the obstacle; And a steering control unit for reducing an assist current value provided to the steering motor before a predetermined angle to reach the contact angle.

The above object is achieved by an image pickup apparatus comprising: a photographing step of photographing the surroundings of a vehicle and outputting an image; Sensing an obstacle around the vehicle; A contact angle calculation step of calculating, when an obstacle is detected around the vehicle, a contact angle at which the wheel should turn to contact the obstacle using the image; And a current control step of reducing an assist current value provided to the steering motor before a predetermined angle to reach the contact angle.

According to the embodiments as described above, the curb is detected around the wheel of the vehicle in advance, and when the curb is judged to be in contact with the wheel, by reducing the assist current before the wheel contacts the curb, It is possible to prevent the lifetime and the durability from deteriorating due to the occurrence of an excessive load on the parts and related parts.

FIG. 1 is a graph showing a relationship between a torque and an assist current in a conventional curved contact.
2 is a schematic configuration diagram of a steering control apparatus according to the present invention.
Figs. 3 to 5 are schematic diagrams for calculating a contact angle at which a wheel contacts a curb according to the present invention. Fig.
FIG. 6 is a graph showing the relationship between the torque and the assist current at the time of contact with the tread according to the steering control of the present invention.
7 is a flowchart illustrating a process of controlling the assist current value according to the curb detection in the steering control apparatus of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

2 is a schematic configuration diagram of a steering control apparatus according to the present invention.

The steering control apparatus according to the present invention can reduce the load by controlling the assist current in advance before the wheel 3 contacts the curb when sensing the curb.

The steering control device includes a torque sensor 10, a steering angle sensor 20, an image pickup device 30, an obstacle detecting portion 40, a contact angle calculating portion 50, a memory 70, a steering control portion 60, (80).

The torque sensor 10 is installed in a steering column connected to a steering wheel and detects a torque of a steering column generated when the steering wheel is steered left and right to output a torque value and outputs the output torque value to the steering control unit 60 . At this time, the torque value may have a positive or negative value depending on whether the steering wheel is steered counterclockwise or clockwise from the neutral position.

The steering angle sensor 20 senses the steering angle indicating the degree of rotation of the steering wheel and the steering direction indicating the rotational direction when the steering wheel is steered, and provides the steering angle to the steering control unit 60. In this case, the steering direction of the steering wheel may be represented by plus or minus. In the present invention, the steering direction of the steering wheel is set to be positive in the clockwise direction for convenience of explanation, and the case where the steering direction is counter- . Accordingly, the steering angle sensed by the steering angle sensor 20 has a positive angle value when steering in the clockwise direction, and a negative angle value when steering in the counterclockwise direction.

The image pickup apparatus 30 may include a plurality of cameras 31 and an image processing section 33 for processing images photographed by the camera 31. [ A plurality of cameras 31 are mounted at predetermined intervals along the periphery of the vehicle 1 and arranged in the direction from the top of the wheel 3 of the vehicle 1 to the bottom of the floor in this embodiment, The wheels 3 of the vehicle 1 and the objects around the vehicle 1 can be photographed. The image processing unit 33 may integrate the images photographed by the plurality of cameras 31 into one image, and may perform the monochrome processing and / or binarization processing on the combined image.

The obstacle detecting unit 40 can set the vicinity of the vehicle 1 as a region of interest (ROI) in the image processed by the image processing unit 33 and determine an obstacle such as a curb in the ROI. Generally, a curb is formed long on one side, and has a roughness different from that of the bottom surface due to differences in level, color, and material from the bottom surface. Accordingly, the obstacle detecting unit 40 can determine the curb using the illuminance difference in the area of interest. On the other hand, the obstacle detecting unit 40 may detect an edge in a binarized image, and may detect an obstacle such as a curb using an edge detected in a region of interest.

The obstacle detecting unit 40 may include an ultrasonic sensor, a laser sensor, a radar sensor, or the like. When an obstacle is detected by these sensors, the obstacle detecting unit 40 can compare the image captured by the camera 31 and determine whether the obstacle is located or not.

The obstacle detecting unit 40 may detect an obstacle such as a curb by various methods, and the present invention is not limited to the specific obstacle determining method used in the obstacle detecting unit 40. [

In the contact angle calculating unit 50, when an obstacle such as a curb is detected in the obstacle detecting unit 40, the contact angle calculating unit 50 calculates the contact angle? Of the wheel 3 ) Can be calculated.

3, the contact angle calculating section 50 measures the distance a between the center of the wheel 3 and the curb and calculates the contact point at which the curb and the wheel 3 meet when the wheel 3 rotates, (P2). At this time, since the distance a between the center of the wheel 3 and the curb is already in the state of knowing the size of the vehicle body or the wheel 3, the distance between the center of the wheel 3 and the curb The straight line distance a between the straight line and the straight line can be calculated. Here, a point where a straight line connecting the center of the wheel 3 and the curb meets the curb is referred to as a contact point P1.

The distance a between the center of the wheel 3 and the curb and the distance between the center of the wheel 3 and the known wheel 3 ), The contact point P2 can be grasped. Here, the distance c between the center of the wheel 3 and the contact point P2 is the radius of the wheel 3.

Then, the contact angle calculating section 50 can calculate the distance b between the contact point P1 and the contact point P2. The distance b between the contact point P1 and the contact point P2 and the distance a from the center of the wheel 3 to the curb are used to determine the contact angle of the wheel 3 for contacting the wheel 3 with the curb, (?) can be calculated.

4, when the vehicle 1 is located at an angle to the curb, the contact angle calculating section 50 calculates the distance a from the center of the wheel 3 to the curb, The contact point P2 at which the wheel 3 meets is detected and then the linear distance d between the wheel 3 and the contact point P2 is calculated. Then, the distance b between the contact point P2 and the contact point P1 is calculated. Then, it is possible to calculate the contact angle [alpha] of the wheel 3 using these three distances.

5, when the wheel 3 is positioned obliquely with respect to the vehicle 1 and the curb, the contact angle calculating section 50 calculates the distance a from the center of the wheel 3 to the curb And the straight line distance d between the wheel 3 and the contact point P2 is calculated after grasping the contact point P2 at which the curb and the wheel 3 meet. Then, the distance b between the contact point P2 and the contact point P1 is calculated. Then, it is possible to calculate the contact angle [alpha] of the wheel 3 using these three distances.

The memory 70 stores information about the diameter of the wheel 3 of the vehicle 1 and the rotation trajectory of the wheel 3. Also stored in the memory 70 is an algorithm for calculating the assist current value provided to the steering motor in accordance with the torque input from the torque sensor 10 and the contact angle alpha.

The steering control unit 60 can calculate the assist current value applied to the steering motor by using the algorithm stored in the memory 70 in accordance with the contact angle alpha calculated by the contact angle calculating unit 50. [ At this time, as shown in FIG. 6, the steering control unit 60 outputs a general assist current value according to the torque up to a predetermined angle before the steering wheel reaches the contact angle [alpha], but the steering wheel rotates at a predetermined angle , The assist current value is decreased along a predetermined slope.

At this time, the predetermined angle may be variously selected by the designer, may be a predetermined angle selected, or may be an angle of a certain ratio with respect to the calculated contact angle [alpha]. For example, when the predetermined angle is set to 5 degrees, if the contact angle? Is 30 degrees, the steering control unit 60 decreases the assist current value according to the predetermined inclination when the steering angle of the steering wheel is 25 degrees. As another example, when the predetermined angle is set to 10% of the contact angle [alpha], when the contact angle [alpha] is 30 degrees, the steering control unit 60 sets the assist current value to the predetermined inclination Lt; / RTI >

On the other hand, the steering control unit 60 can calculate the assist current value based on the maximum steering angle of the steering wheel when the contact angle? Exceeds the maximum steering angle of the steering wheel. That is, when the contact angle? Exceeds the maximum steering angle of the steering wheel, the steering control of the steering wheel stops before the wheel 3 touches the curb, so that the steering control unit 60 steers the assist current value rapidly There is no need to reduce it.

The driving circuit unit 80 receives the control signal corresponding to the assist current value selected by the steering control unit 60 and controls the current supplied to the steering motor.

A process of controlling the assist current value according to the curb detection in the steering control apparatus having such a configuration will now be described with reference to FIG.

A plurality of cameras 31 photographs the periphery of the vehicle 1 during the operation or parking of the vehicle 1 (S700), and the photographed images are integrated in the image processing unit 33 and subjected to monochrome processing and / And transmitted to the obstacle detecting unit 40 (S710).

The obstacle detecting unit 40 may detect an obstacle such as a curb using a sensor or an image (S720). When an obstacle such as a curb is detected, the contact angle calculation unit 50 may calculate the contact angle alpha for contacting the wheel 3 with the curb using the method disclosed in Figs. 3 to 5 (S730).

The steering control unit 60 is provided with information on the contact angle?. When the contact angle alpha is smaller than the maximum steering angle of the steering wheel in step S740, the steering control unit 60 calculates the assist current value based on the torque and the steering angle up to a predetermined angle (S750-N, S755) Above the angle, the assist current value is decreased according to the preset slope (S750-Y, S760).

On the other hand, if the contact angle? Is larger than the maximum steering angle of the steering wheel, the steering control unit may calculate the assist current value based on the steering angle, the torque, the steering angle speed, and the like (S745).

The assist current value calculated by the steering control unit 60 is transmitted to the drive circuit unit 80 as a control signal and the drive circuit unit 80 supplies the assist current corresponding to the assist current value calculated by the steering control unit 60 to the steering motor (S770).

As described above, in the present invention, the curb is detected beforehand around the wheel 3 of the vehicle 1, and when the curb is judged to contact the wheel 3, the assist current is reduced before the wheel 3 contacts the curb It is possible to prevent an excessive load from being generated in the steering motor, the battery, and related parts, so that the service life and the durability are prevented from being lowered.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

1: vehicle 3: wheels
30: Image pickup device 31: Camera
40: an obstacle detecting unit 50: a contact angle calculating unit
60:

Claims (12)

An image pickup apparatus, comprising: a plurality of cameras; an image pickup device mounted on the vehicle and outputting an image of the surroundings of the vehicle;
An obstacle detection unit for detecting an obstacle around the vehicle;
A contact angle calculating unit for calculating a contact angle at which the wheel should be rotated to contact the obstacle by using the image when the obstacle detecting unit detects the obstacle; And
And a steering control section for reducing an assist current value provided to the steering motor before a predetermined angle to reach the contact angle,
The contact angle calculating unit calculates the contact angle between the contact point at which the wheel contacts the obstacle at the time of turning the wheel and the contact point at which the straight line connecting the obstacle at the axis of the wheel contacts the obstacle, And calculates the contact angle using a distance. delete The method according to claim 1,
Wherein the contact angle calculating section calculates the contact angle by further using a straight line connecting the wheel at a contact point at which the wheel contacts the obstacle when the wheel rotates. The method according to claim 1,
Wherein the steering control unit sets a certain ratio of the contact angle to a predetermined angle and decreases the assist current along a preset predetermined slope when the predetermined angle is reached. The method according to claim 1,
Wherein the steering control unit sets the predetermined angle to a predetermined angle and decreases the assist current according to a predetermined slope when the predetermined angle is reached. The method according to claim 1,
Wherein the steering control unit calculates the assist current value provided to the steering motor according to the steering angle when the contact angle is larger than the maximum steering angle of the steering wheel. A photographing step of photographing the surroundings of the vehicle and outputting an image;
Sensing an obstacle around the vehicle;
A contact angle calculation step of calculating, when an obstacle is detected around the vehicle, a contact angle at which the wheel should turn to contact the obstacle using the image; And
And a current control step of reducing an assist current value provided to the steering motor before a predetermined angle to reach the contact angle,
The contact angle calculating step may include calculating a contact distance between the contact point at which the wheel contacts the obstacle at the time of the rotation of the wheel and a straight line connecting the obstacle at the axis of the wheel at a contact point And calculating the contact angle using a distance between the steering angle and the steering angle. delete 8. The method of claim 7,
Wherein the contact angle calculating step includes calculating the contact angle by further using a straight line connecting the wheel at a contact point at which the wheel contacts the obstacle when the wheel rotates. 8. The method of claim 7,
Wherein the current control step includes setting a certain ratio of the contact angle to a predetermined angle and decreasing the assist current along a predetermined constant slope when the predetermined angle is reached. 8. The method of claim 7,
Wherein the current control step includes setting the predetermined angle at an angle and decreasing the assist current according to a predetermined constant slope when the predetermined angle is reached. 8. The method of claim 7,
Wherein the current control step includes calculating an assist current value provided to the steering motor according to the steering angle when the contact angle is larger than the maximum steering angle of the steering wheel.

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