Patent Description:
A steel bar straightener includes a plurality of rollers and may be largely divided into a roller pressure system and a rotary system according to a straightening system. Both systems control a pressure of the roller to straighten a steel bar, and according to the pressure applied to the roller, the steel bar coming out of the steel bar straightener may be bent. Therefore, in the related art, there is an inconvenience of manually controlling the pressure applied to the roller by manually checking, or with the naked eye, whether the steel bar coming out through an outlet of the steel bar straightener is bent. <CIT> discloses a cutting machine to correct and bend coil rebar.

An object of the present disclosure is to provide a method and an apparatus capable of automatically controlling a pressure applied to each roller of a steel bar straightener by detecting bending of a steel bar through imaging of an image.

According to an embodiment of the present disclosure, there is provided a method of controlling a steel bar straightener, the method including: acquiring an image that is obtained by imaging an end point of a steel bar when the steel bar output through an outlet of the steel bar straightener arrives at a preset position; detecting a region of a control map that matches with an end point of the steel bar of an image when matching the image with the control map configured of a plurality of regions; and controlling the steel bar straightener based on a preset control value mapped in a region of the control map.

According to another embodiment of the present disclosure, there is provided an apparatus for controlling a steel bar straightener, the apparatus including: an imaging unit that acquires an image obtained by imaging a steel bar output through an outlet of a steel bar straightener; a region detecting unit that detects a region of a control map that matches with an end point of the steel bar of an image when matching the image with the control map configured of a plurality of regions; and a control unit that controls the steel bar straightener based on a preset control value mapped in a region of the control map.

According to an embodiment of the present disclosure, it is possible to correct bending of the steel bar output from the steel bar straightener through automatic control. According to another embodiment, in a case where the steel bar straightener is capable of simultaneously straightening two or more steel bars, straightening control for two or more steel bars may be performed simultaneously.

Hereinafter, a method of and apparatus for controlling a steel bar straightener according to the present disclosure will be described in detail with reference to the accompanying drawings.

<FIG> is a diagram illustrating a schematic configuration of an entire system for straightening a steel bar according to an embodiment of the present disclosure.

Referring to <FIG>, a steel bar straightener <NUM> largely includes an inlet <NUM> into which the steel bar is inserted, a large pressure roll <NUM> and a fine correction roll <NUM> that straighten the steel bar, and an outlet <NUM> through which the steel bar is discharged. The large pressure roll <NUM> and the fine correction roll <NUM> include a plurality of rollers and control a position and a pressure of each roller to straighten the steel bar. In some embodiments, a steel bar guide <NUM> may be or may not be further included in front of the outlet <NUM> to guide a discharging direction of the steel bar so that the steel bar may be directly discharged to the front. In the present embodiment, the steel bar straightener <NUM> is only an example for aiding understanding and the present disclosure is not necessarily limited thereto.

The control apparatus <NUM> images the steel bar output from the steel bar straightener <NUM> by using an image capturing apparatus <NUM>, analyzes the captured image, automatically detects whether the steel bar is normally straightened or bent, and then automatically generates a control signal if the steel bar is bent to control the large pressure roll <NUM> or the fine correction roll <NUM> of the steel bar straightener <NUM>. A configuration of an embodiment of the control apparatus <NUM> is illustrated in <FIG>.

The image capturing apparatus <NUM> is an apparatus for capturing a moving image or a still image, and captures an image of an end point of the steel bar at a location spaced at a certain distance from the outlet <NUM> of the steel bar straightener <NUM>. The image capturing apparatus <NUM> is preferably located in front of the outlet <NUM> so that the bending of the steel bar may be grasped, but it may be installed anywhere at a position where the bending of the steel bar may be grasped.

<FIG> is a view illustrating an example of a detailed configuration of a steel bar straightener used in an embodiment of the present disclosure.

Referring to <FIG>, the steel bar straightener includes a large pressure roll <NUM> that is configured of a plurality of rollers and applies a large pressure to a steel bar <NUM>, and fine correction rolls <NUM> and <NUM> capable of finely correcting the bending of the steel bar, or the like.

In some embodiments, in the steel bar straightener, the large pressure rolls <NUM> and the fine correction rolls <NUM> and <NUM> may be present in pairs so that two steel bars may be straightened simultaneously. The fine correction roll may be configured of a left-right correction roll <NUM> moving left and right, and a vertical correction roll <NUM> moving up and down. It is possible to control the bending of the steel bar discharged through the outlet <NUM> according to the left-right movement of the left-right correction roll <NUM> or the vertical movement of the vertical correction roll <NUM>.

An influence of the movement of the left-right correction roll <NUM> and the vertical correction roll <NUM> on the steel bar <NUM> output through the outlet <NUM> may be grasped in advance through an experimental or empirical analysis. Therefore, in the following embodiments, control values to be input to the left-right correction roll <NUM> and the vertical correction roll <NUM> according to a degree of bending of the steel bar <NUM> output through the outlet <NUM> are assumed to be set in advance as illustrated in <FIG> and <FIG>.

<FIG> is a view illustrating an example in which a steel bar straightener according to an embodiment of the present disclosure outputs one steel bar.

Referring to <FIG>, steel bars <NUM> and <NUM> may be bent when being output for a certain length from the outlet <NUM> of the steel bar straightener. If bending of the steel bar <NUM> occurs, it is necessary to control the large pressure roll <NUM> or the fine correction roll <NUM> in the steel bar straightener <NUM>. For example, it is possible to correct the bending of the steel bar through the movement of the left-right correction roll or the vertical correction roll of the fine correction roll <NUM>.

The control apparatus <NUM> obtains an X-Y plane image by using the image capturing apparatus <NUM> located at a position spaced apart from the steel bar straightener <NUM> by a certain distance in a Z-axis direction in order to grasp the bending of the steel bar. An example of an image capturing method for grasping the end point of the steel bar is illustrated in <FIG>.

<FIG> is a view illustrating an example in which a steel bar straightener according to an embodiment of the present disclosure simultaneously outputs two steel bars.

Referring to <FIG>, two steel bars <NUM> and <NUM> are output simultaneously from the outlet <NUM> of the steel bar straightener. Bending patterns of the two steel bars <NUM> and <NUM> may be different. Therefore, the control apparatus <NUM> needs to control the steel bar straightener by generating respective control values for the two steel bars <NUM> and <NUM>.

The two steel bars <NUM> and <NUM> output simultaneously may be twisted and bent in different directions. In this case, it may be difficult to grasp which steel bar is output from which position of the outlet <NUM> if only the positions of the end points of the two steel bars, which are output for a certain length, are grasped. As in the present embodiment, the positions of the end points of the two steel bars <NUM> and <NUM> at the starting position of the outlet <NUM> and the positions thereof after output for a certain length are changed. Therefore, the steel bar straightener may not be controlled by simply grasping only the end points of the two steel bars which are output for a certain length. A method of mapping the end point of the steel bar output for a certain length and the starting position of the outlet of the steel bar will be described with reference to <FIG>.

<FIG> is a view illustrating an example of an image capturing method according to an embodiment of the present disclosure.

Referring to <FIG>, an image capturing apparatus <NUM> includes an infrared generator, an infrared detection sensor, and an infrared camera. The infrared ray generator emits an infrared ray <NUM> in an imaging direction, and the infrared detection sensor is a kind of a Time of Flight (ToF) sensor and measures a time until the infrared ray hits the steel bar <NUM> and returns after the infrared ray is emitted to grasp a distance between the image capturing apparatus <NUM> and an object. The infrared camera captures the infrared image.

For example, in order to, by the image capturing apparatus <NUM>, capture an image of the steel bar <NUM> output from the outlet <NUM> to a certain length A, a position that is a certain distance B away from the image capturing apparatus <NUM> may be set as an imaging position. The image capturing apparatus <NUM> grasps whether the steel bar <NUM> arrives at the imaging position (that is, when the steel bar is located at the distance B from the image capturing apparatus) through the infrared detection sensor, and uses the infrared camera when the steel bar <NUM> arrives at the imaging position to image the end point of the steel bar. The image capturing apparatus <NUM> emits an infrared ray <NUM> and captures an image by using the infrared ray <NUM> that hits the steel bar <NUM> and returns. Accordingly, since the end point of the steel bar is displayed brighter than a background region in the infrared image, the control apparatus <NUM> may easily identify the end point of the steel bar. In addition, the image capturing apparatus <NUM> may capture an image of the starting position where the steel bar is output from the outlet <NUM> to obtain the image.

In some embodiments, in front of the outlet <NUM> of the steel bar straightener, there may be the steel bar guide <NUM> that guides the direction of the steel bar. The steel bar guide <NUM> guides the advancing direction of the steel bar only when the steel bar is output for a certain length from the outlet <NUM>, and the steel bar guide may not guide the advancing direction of the steel bar away from the steel bar when the steel bar is output for a certain length or more. In order to accurately grasp the degree of bending of the steel bar, it is preferable that the steel bar guide does not guide the advancing direction of the steel bar.

Therefore, if the steel bar guide <NUM> is separated from the steel bar <NUM> before the steel bar <NUM> output from the outlet <NUM> arrives at the image capturing position (distance A), there may be a case where the end point of the steel bar is shaken at the image capturing position. If the end point of the steel bar is shaken, it is difficult to grasp the exact location of the end point of the steel bar. As an example for solving this problem, the image capturing apparatus <NUM> captures infrared images of several tens of frames per second when the steel bar arrives at the imaging position (that is, the distance B from the image capturing apparatus), and the control apparatus <NUM> may grasp the position of the end point of the steel bar by averaging the positions of the end points of the steel bars grasped in the plurality of frames.

If the number of steel bars output from the outlet <NUM> is one as illustrated in <FIG>, the control apparatus <NUM> grasps the end point of one steel bar, and if the number of steel bars output from the outlet is two as illustrated in <FIG>, the control apparatus <NUM> grasps the end points of the two steel bars.

In a case of grasping the end points of the two steel bars in the images captured by the image capturing apparatus, it is necessary to grasp where each end point is output from the outlet so that the control value for the steel bar may be correctly input to the steel bar straightener.

<FIG> is a diagram illustrating an example of a captured image of an end point of a steel bar output from a steel bar straightener according to an embodiment of the present disclosure.

Referring to <FIG>, the image capturing apparatus captures the image of the end point of the steel bar until the steel bar is output for a certain length from the starting position of the outlet. The image capturing apparatus may capture an image by using the infrared camera as illustrated in <FIG> or may capture an image by using a general camera utilizing visible light. The image capturing apparatus may capture the images of several tens of frames per second.

The control apparatus sequentially analyzes the images of several tens of frames imaged by the image capturing apparatus to grasp a movement trajectory of the end point of the steel bar output from the outlet <NUM>. For example, in this embodiment, a case is illustrated in which a steel bar <NUM> located on the left from the starting position of the outlet <NUM> is output and bent right upwards (<NUM>-<NUM>-<NUM>-<NUM>), and a steel bar <NUM> located on the right from the starting position of the outlet <NUM> is output and bent left upwards (<NUM>-<NUM>-<NUM>-<NUM>).

In a case where the steel bars are twisted and output as in the example of <FIG>, it is possible to know which steel bar is output from which position of the outlet through the movement trajectories of the two end point of the steel bars in the images of several tens of frames imaged by the image capturing apparatus.

If the movement trajectory of any one of the two steel bars is grasped, the movement trajectory of the other steel bar is naturally grasped. Therefore, in some embodiments, the control apparatus <NUM> may grasp only the movement trajectory of one of the two steel bars.

In one embodiment, the control apparatus <NUM> may apply simultaneously the two methods of <FIG> and <FIG>. For example, as illustrated in <FIG>, the image capturing apparatus <NUM> uses the infrared camera or the general camera to capture a plurality of images at predetermine time intervals until the steel bar is output for a certain length from the starting position of the outlet <NUM>. In addition, as illustrated in <FIG>, the image capturing apparatus <NUM> captures the infrared image when the steel bar is output for a certain length and arrives at the imaging position. The control apparatus <NUM> grasps the movement trajectory of at least one end point of the steel bar through the image captured by the method of <FIG>, and grasps the end point of the steel bar outputting for a certain length grasped by the method of <FIG> is at which starting position of the outlet by using the movement trajectory.

In another embodiment, the control apparatus <NUM> may use deep learning to better distinguish between the end point of the steel bar and the background when analyzing a plurality of frame images to grasp the movement trajectory of the end point of the steel bar. For example, the control apparatus <NUM> accurately identifies the end point of the steel bar in the image acquired through the image capturing apparatus <NUM> after deep learning by using a plurality of sample images for the end point of the steel bar and a plurality of sample images for the background. For example, a Haar like feature or Haar Training may be applied to the deep learning.

<FIG> and <FIG> are diagrams illustrating examples of control maps according to the present disclosure.

<FIG> and <FIG> illustrate the control maps representing control values for a pair of fine correction rolls in a case where the steel bar straightener straightens simultaneously two steel bars. For example, in a case where the steel bar straightener is configured of a pair of a first inside fine correction rolls (that is, a first left-right correction roll and a first vertical correction roll) and a second outside fine correction rolls (that is, a second left-right correction roll and a second vertical correction roll), <FIG> may be a control map <NUM> for controlling the first inside fine correction rolls, and <FIG> may be a control map <NUM> for controlling the second outside fine correction rolls.

Referring to <FIG> and <FIG>, the control maps <NUM> and <NUM> are configured of a plurality of regions for grasping the degree of bending of the steel bar. In addition, each region of the control maps <NUM> and <NUM> is mapped with control values of the fine correction rolls (left-right correction roll and vertical correction roll). The control value of the fine correction roll is preset according to characteristics of the straightener.

The control maps <NUM> and <NUM> respectively include original points <NUM> and <NUM> for matching the end point of the first steel bar at the output starting position of the outlet <NUM>. If the steel bar is bent while being output from the outlet <NUM>, the end point of the second steel bar according to the degree of bending is relatively far from the end point of the first steel bar.

<FIG> is a diagram illustrating an example in which a control map and an end point of a steel bar are matched according to an embodiment of the present disclosure.

Referring to <FIG>, the control apparatus matches an end point <NUM> of the first steel bar at the output starting position of the outlet <NUM> of the steel bar straightener with an original point of a control map <NUM>. In addition, the control apparatus grasps which region of the control map <NUM> matches an end point of the second steel bar <NUM> when the steel bar is output for a preset length from the outlet <NUM>.

In the present embodiment, if the control map <NUM> is equal to the control map <NUM> of <FIG>, the region of the control map <NUM>, with which the end point <NUM> of the second steel bar is matched, is a region of the number <NUM>. Referring to <FIG>, control values of the first left-right correction roll and the first vertical correction roll that match the region of the number <NUM> are <NUM> and <NUM>, respectively. The control apparatus controls the steel bar straightener by using the corresponding control values.

<FIG> is a flowchart illustrating an example of a method of controlling the steel bar straightener according to the present disclosure.

Referring to <FIG>, the control apparatus <NUM> captures the image of the steel bar output through the outlet <NUM> of the steel bar straightener (S1000). When the steel bar output through the outlet passes through at least two preset locations, the control apparatus <NUM> captures the image of the end point of the steel bar. For example, the control apparatus <NUM> controls the image capturing apparatus <NUM> to capture the images at the starting position when the steel bar is output from the outlet <NUM> and at a position where the steel bar is output for a certain length (for example, <NUM>) from the outlet <NUM>.

In one embodiment, the control apparatus <NUM> may grasp the end point of the steel bar by capturing an infrared image by using the image capturing apparatus <NUM> illustrated in <FIG> when the steel bar is output for a certain length from the outlet. When the end point of the steel bar is imaged, if there is shaking of the steel bar, the control apparatus <NUM> may grasp the end point of the steel bar by averaging the positions of the end points of the steel bars grasped in the images of several tens of frames.

In another embodiment, the control apparatus <NUM> may grasp the movement trajectory of the end point of the steel bar by capturing images at predetermine time intervals (for example, several tens of frames per second) by the method illustrated in <FIG> until the steel bar is output for a certain length from the starting position of the outlet <NUM>. In particular, when two or more steel bars are simultaneously output from the outlet <NUM>, it may grasp, through the movement trajectory, which steel bar is output from which position of the outlet <NUM>. Therefore, the control values according to the bending of each steel bar are respectively generated, and the steel bar straightener is controlled.

In another embodiment, by applying simultaneously the methods of <FIG> and <FIG>, the position of the end point of the steel bar may be grasped when the steel bar is output for a certain length along with the movement trajectory of the steel bar. In a case where two or more steel bars are output simultaneously from the outlet <NUM>, the control apparatus <NUM> may grasp that the end point of the steel bar grasped by the method of <FIG> is output from which starting position of the outlet, through the movement trajectory grasped by the method of <FIG>.

The control apparatus <NUM> respectively grasps the positions of the end points of the steel bars from at least two captured images, and then matches the end point of the steel bar with the original point of the control map to correspond thereto (S1010). For example, the control apparatus <NUM> aligns the end point of the steel bar of the first captured image (that is, the image when the steel bar is at the starting position of the outlet <NUM>) with the original point of the control map, and then grasps whether the position of the end point of the steel bar of the captured image (that is, the image at the location where the steel bar is output for a certain length) corresponds to which region of the control map.

The control apparatus <NUM> controls the steel bar straightener by using the control value set in the region of the control map corresponding to the second imaged end point of the steel bar (S1020).

<FIG> is a diagram illustrating a configuration of an embodiment of a control apparatus according to the present disclosure.

Referring to <FIG>, the control apparatus <NUM> of the steel bar straightener includes an imaging unit <NUM>, a region grasping unit <NUM>, and a control unit <NUM>.

The imaging unit <NUM> images, through the image capturing apparatus <NUM>, the steel bar output through the outlet <NUM> of the steel bar straightener <NUM>. The imaging unit <NUM> may image the steel bar whenever the steel bar output through the outlet <NUM> of the steel bar straightener <NUM> passes through at least two or more preset positions. For example, referring to <FIG>, the imaging unit <NUM> may respectively capture the first image and the second image at time points when the steel bar <NUM> is output from the outlet <NUM> and when the steel bar <NUM> is output for a certain length (for example, <NUM>) from the outlet <NUM>.

The imaging unit <NUM> may receive a trigger signal for capturing the image from the steel bar straightener <NUM> at two predetermine positions. When the steel bar straightener <NUM> detects that the steel bar arrives at the end of the outlet <NUM> through a sensor located at the end of the outlet <NUM>, the trigger signal may be generated and transmitted to the imaging unit <NUM>. Alternatively, the steel bar straightener <NUM> detects the rotation of the roller at either of the large pressure roll <NUM> or the fine correction roll <NUM>, so that it is possible to detect how much of the steel bar located at the end of the outlet <NUM> is output out of the outlet <NUM>, and when the steel bar is output for a preset length, the trigger signal may be generated and transmitted to the imaging unit <NUM>.

In another embodiment, the imaging unit <NUM> may capture the image by detecting that the steel bar is output for a certain length from the outlet by using the infrared sensor with the method illustrated in <FIG>.

In another embodiment, the imaging unit <NUM> may include a first imaging unit <NUM> that captures an image by using visible light and a second imaging unit <NUM> that captures infrared image. The first imaging unit <NUM> may capture the image by using the method of <FIG>, and the second imaging unit <NUM> may capture the image by using the method of <FIG>. In some embodiments, the imaging unit <NUM> may include only one of the first imaging unit and the second imaging unit. In another embodiment, the imaging unit <NUM> may grasp the image of the end point of the steel bar and the movement trajectory thereof by using only the second imaging unit <NUM> with the method of <FIG> and <FIG>. Various conventional image analysis methods may be applied to grasp the end point of steel bar in the captured image.

The region grasping unit <NUM> grasps the movement (that is, bending) of the end points of the steel bars by causing each end point of the steel bar grasped in at least two images captured by the imaging unit <NUM> to correspond to the control map configured of a plurality of regions. An example of the control map is illustrated in <FIG> and <FIG>.

For example, the imaging unit <NUM> captures the first image at the time point when the steel bar is output through the outlet <NUM> and the second image at the time point when the steel bar is output for a certain length (for example, <NUM>) from the outlet <NUM>. The region grasping unit <NUM> matches the end points of the steel bars grasped in the first image with the original points <NUM> and <NUM> of the control maps <NUM> and <NUM> including a plurality of regions as illustrated in <FIG> or <FIG>, and grasps which region of the control map <NUM> or <NUM> matches with a relative position of the end point of the steel bar grasped in the second image. An example of the method of matching the control map with the end point of the steel bar is also illustrated in <FIG>.

The control unit <NUM> grasps the region indicated by the end point of the steel bar of the second image in the control map, and controls the steel bar straightener <NUM> by using a preset control value mapped to the region. The control maps <NUM> and <NUM> are divided into the plurality of regions as illustrated in <FIG> or <FIG>, and the preset control value is mapped in each region. Therefore, as illustrated in <FIG>, after matching the end point <NUM> of the steel bar of the first image with the original point <NUM> of the control map <NUM>, if the end point <NUM> of the steel bar of the second image corresponds to the region of the number <NUM> of the control map <NUM>, the control unit <NUM> controls the left-right correction roll, the vertical correction roll, or the like by using a preset control value in the region of the number <NUM> of the control map <NUM>.

Claim 1:
A method of controlling a steel bar straightener (<NUM>), the method comprising:
acquiring an image that is obtained by imaging an end point of a steel bar when the steel bar output through an outlet (<NUM>) of the steel bar straightener arrives at a preset position;
determining a region of a control map (<NUM>; <NUM>; <NUM>) that matches with an end point of the steel bar of an image when matching the image with the control map configured of a plurality of regions; and
controlling the steel bar straightener (<NUM>) based on a preset control value mapped in a region of the control map (<NUM>; <NUM>; <NUM>).