KR20180116832A - Apparatus for detecting a pipe position and pose, and its method for detecting a pipe position and pose - Google Patents

Abstract

According to the present invention, pipe position and posture detection device and method are disclosed. The device and method obtain an image of a pipe through a laser and a camera mounted on a hand climbing a pipe, process the image, and calculate position data required for an operation by detecting the position of an adjacent pipe, thereby providing the position data to an operation requiring the position data. The disclosed pipe position and posture detection device is a device for detecting a position and a posture of a pipe to be moved in a work place in which one or more pipes are connected to each other, and comprises: a main board; a camera unit which is mounted on the upper side of the main board and includes a camera for photographing the pipe; a laser scanning unit which is mounted on the lower side of the camera unit on the main board and emits laser beams to the pipe to scan the pipe; a rotation cam which adjusts a transmission angle of the laser beams of the laser scanning unit by a rotation operation; a motor unit which provides rotation force generated according to the rotation of the motor to the rotation cam; and a control unit which transmits laser beams to the pipe through the laser scanning unit, obtains a pipe image by photographing a pipe in which laser beams appear in a line form at regular time intervals through the camera unit, and detects and controls the outline, position, and posture of the pipe by processing the obtained pipe image.

Description

TECHNICAL FIELD The present invention relates to a pipe position and posture detection apparatus, and a pipe position and posture detection method using the same.

The present invention relates to a pipe position and attitude detection apparatus and a pipe position and attitude detection method using the same. More particularly, the present invention relates to a robot and a pipe for climbing a pipe, By obtaining the image of the pipe, the position of an arbitrary nearby pipe is detected by using the slope and slice value of the pipe outline obtained by processing the image, and the position data necessary for the operation is calculated to provide the position data to the necessary work, Pipe position and attitude detection device, which improves productivity by omitting the guide lane installation work necessary for automatic welding and enables the robot hand to catch the peripheral pipe for the work according to the pipe shape, and the pipe position and attitude detection method using it .

In general, a pipe climbing robot is a robot that is installed in a very high area, such as a spray pipe installed in a reactor containment vessel, and enables safety inspection of main equipment at a point which is very difficult for human access.

When inspecting a large structure or pipe system installed in a large stadium or a power plant and inspecting a very high area, it is possible to replace a person's role by sending a pipe climbing robot.

Such a pipe climbing robot is required to ascertain the position and attitude data of the target pipe in order to ascend the pipe to examine the piping installed in the stadium of the stadium or the nuclear power plant.

However, since the position data of a pipe is generally difficult to obtain and its accuracy is low, it is often the case that a person constructs an environment necessary for a direct operation. For example, in the case of welding a pipe, there is a case where a pipe is fixed for welding and a guide lane is installed to perform robot welding. In such a case, it is troublesome to install a guide rail every welding.

Korean Registered Patent No. 10-1502394 (registered on March 09, 20150)

An object of the present invention to solve the above-mentioned problems is to obtain an image of a pipe through a camera mounted on a robot hand and a laser in an environment where a robot or pipe climbing a pipe is cut and processed, By using the slope and slice values of the obtained pipe outline, it is possible to detect the position of an arbitrary neighboring pipe, calculate the position data necessary for the work, and provide the position data to the necessary work, thereby omitting the guide lane installation work The present invention provides a pipe position and posture detection device and a pipe position and posture detection method using the pipe position and posture detection device.

According to an aspect of the present invention, there is provided an apparatus for detecting a position and a pose of a pipe to be moved in a workplace where one or more pipes are connected to each other, the apparatus comprising: a main board; A camera unit mounted on the main board and having a camera for photographing the pipe; A laser scanning unit mounted on the main board on a lower side of the camera unit, for scanning the pipe by sending a laser beam to the pipe; A rotation cam for adjusting a delivery angle of the laser beam of the laser scanning unit by a rotation operation; A motor part for providing a rotational force to the rotation cam in accordance with rotation of the motor; And a controller for controlling the laser scanning unit to transmit the laser beam to the pipe, to photograph the pipe in the form of a line of the laser beam through the camera unit at a predetermined time to acquire the pipe image, And a control unit for detecting and controlling a position and a posture.

The rotation cam may include: a coupling portion for coupling to the motor portion; A coupling hole through which the shaft of the motor is inserted into the coupling portion; A first convex portion having a convex semi-circular cross section at one side with respect to a center line in a direction perpendicular to the axial direction of the motor; And a second convex portion having a semicircular shape convex to the half of the semicircular shape of the first convex portion on the other side with respect to a center line in a direction perpendicular to the axial direction of the motor.

In addition, in the rotation cam, the first convex portion and the second convex portion are formed symmetrically with respect to the center line, and the first convex portion is not symmetrical with the second convex portion, A rectangular surface having a length corresponding to the radius of the rectangular surface can be formed.

In addition, the laser scanning unit may have a cylindrical shape and may include a delivery unit for delivering a laser beam to the pipe; And a coupling part for fixing and coupling the delivery part to the main board, wherein the delivery part is fixed by the coupling part so as to contact the rotation cam in a state of being mounted on the rotation cam, And can be fixedly coupled to the main board through the coupling unit so as to be rotatable so that the feeding angle of the laser beam is adjusted according to the operation.

In addition, in the laser scanning unit, the feeder may be lifted up along the circular arc of the first convex portion in accordance with the rotation operation of the rotation cam, and may be adjusted upwards And the second convex portion is brought into contact with the second convex portion after passing through a point where the arc of the first convex portion ends according to the continuous rotation operation of the rotation cam, so that the delivery angle of the laser beam can be adjusted to the maximum downward angle.

The camera unit may further include: a camera for photographing the pipe; A fixing unit for fixing the camera; And a base portion for supporting and supporting the fixing portion on the main board.

In addition, the controller obtains the pipe image at a predetermined time interval, calculates two end point coordinates of the laser line appearing in each frame obtained, connects the two end point coordinates of the laser line calculated for each frame, The two straight lines obtained are recognized as a pipe outline, and the distance to the pipe object corresponding to the size of the pipe image is calculated.

Also, the controller compares the previous frame and the current frame with respect to the pipe image obtained in units of frames at the predetermined time intervals to obtain a difference image, and calculates coordinates of the two end points of the laser line through the obtained difference image , The most similar regression line can be obtained with the coordinates calculated for all the difference images and recognized as the pipe outline.

The control unit may perform preprocessing on the pipe image obtained on a frame-by-frame basis at predetermined time intervals through Gaussian filter and canny edge detection, and output the preprocessed image to the outline of the pipe through a Hough Line Transform The candidate group is detected, and the outline candidate groups detected for each frame are compared with each other, so that the final pipe outline can be derived.

According to another aspect of the present invention, there is provided a method for detecting a pipe position and an attitude, comprising the steps of: (a) transmitting a laser beam to a laser scanning unit; (b) capturing a pipe, in which the camera unit displays the line of the laser beam, with a camera to obtain a pipe image; (c) adjusting the feeding angle of the laser beam as the rotating cam rotates by the rotational force of the motor unit in the laser scanning unit; (d) storing, by a frame, the pipe image obtained by the control unit at predetermined time intervals through the camera unit; And (e) the control unit processes the obtained pipe image to obtain a pipe outline and a position and a position.

In addition, in the step (c), the laser scanning unit may be lifted along the arc of the first convex portion in accordance with the rotation of the rotation cam while the delivery unit is placed on the rotation cam, And the delivery portion is brought into contact with the second convex portion so that the delivery angle of the laser beam is adjusted to the maximum downward angle when the circular arc of the first convex portion is finished according to the continuous rotation operation of the rotation cam .

In the step (e), the controller obtains the pipe image at a predetermined time interval, calculates coordinates of two end points of the laser line in each frame obtained, Two parallel straight lines obtained by connecting the coordinates of the two end points are recognized as a pipe outline, and the distance to the pipe object corresponding to the size of the pipe image is calculated.

In the step (e), the controller compares the previous frame and the current frame with respect to the pipe image obtained in units of frames at the predetermined time intervals to obtain a difference image, And obtains the most similar regression line with the calculated coordinates for all the difference images and recognizes the pipe as the pipe outline.

In the step (e), the controller performs preprocessing on the pipe image obtained on a frame-by-frame basis at predetermined time intervals through Gaussian filter and canny edge detection, and performs a Hough Line Transform ), And the outline candidate groups detected for each frame are compared with each other to derive the final pipe outline.

Other aspects, advantages and features of the present invention will become more apparent on the basis of the following description in the entire specification, including the following sections: Brief Description of the Drawings, Detailed Description, and Claims.

According to the present invention, a method using a difference image obtained through a laser line with respect to a pipe image is combined with a line extraction method using Hough transform to finally derive the outline of the pipe. Therefore, the reliability is very high, Can be detected. In other words, it can detect the position and posture of the pipe, more specifically, detect the position of any nearby pipe in the environment of cutting and processing the robot or pipe climbing the pipe, and present the position data necessary for the work, .

In addition, the process of detecting the outline in the image processing process for determining the position of the gripper can be completed more quickly and accurately by the pipe climbing robot.

In addition, by reducing the mass of the entire image recognition unit, it is possible to minimize the overload that may occur in the joint of the robot.

In addition, it is possible to reduce the inconvenience that a person directly inputs the outline of the pipe to the control unit, and automatically recognize the outline of the pipe, thereby contributing to the detection of the outline of the pipe more quickly and accurately.

Then, the pipe climbing robot estimates the position and posture of the pipe so that the robot can grasp the pipe accurately and quickly. The robot cutting and processing the pipe detects the position of the nearby pipe and presents the position data required for the work Can be used to automate tasks.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram schematically showing the configuration of a pipe position and orientation detecting apparatus according to an embodiment of the present invention; FIG.
2 is an external perspective view schematically showing a configuration of a camera unit according to an embodiment of the present invention.
3 is an external perspective view schematically showing a configuration of a laser scanning unit according to an embodiment of the present invention.
4 is an external perspective view showing a configuration of a rotation cam according to an embodiment of the present invention.
5 is a flowchart illustrating a method for detecting a pipe position and posture according to an embodiment of the present invention.
6 is a flowchart illustrating a pipe image processing process of the controller according to the embodiment of the present invention.
FIG. 7 is a diagram illustrating coordinate transformation between an actual pipe image and a camera image image by a pipe climbing robot according to an embodiment of the present invention.
8 is a view showing a camera image before moving a hand of a pipe climbing robot according to an embodiment of the present invention.
9 is a view showing a camera image after moving a hand of a pipe climbing robot according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as " comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

If any part is referred to as being " on " another part, it may be directly on the other part or may be accompanied by another part therebetween. In contrast, when a section is referred to as being " directly above " another section, no other section is involved.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

Terms indicating relative space such as " below ", " above ", and the like may be used to more easily describe the relationship to other portions of a portion shown in the figures. These terms are intended to include other meanings or acts of the apparatus in use, as well as intended meanings in the drawings. For example, when inverting a device in the figures, certain portions that are described as being " below " other portions are described as being " above " other portions. Thus, an exemplary term " below " includes both up and down directions. The device can be rotated by 90 degrees or rotated at different angles, and terms indicating relative space are interpreted accordingly.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram schematically showing the configuration of a pipe position and orientation detecting apparatus according to an embodiment of the present invention; FIG.

1, a pipe position and orientation detecting apparatus 100 according to the present invention includes a main board 110, a camera unit 120, a laser scanning unit 130, a rotation cam 140, A control unit 150 and a motor unit 160.

The apparatus 100 for detecting a pipe position and attitude according to the present invention detects the position and posture of a pipe to move in order to move one pipe to another pipe while climbing one pipe in a workplace where one or more pipes are connected to each other. Therefore, in the embodiment of the present invention, the pipe position and attitude detection apparatus 100 will be described as a robot for climbing a pipe.

The main board 110 is a board for mounting and supporting the camera unit 120 and the laser scanning unit 130.

The camera unit 120 is mounted on the upper side of the main board and has a camera for photographing the pipe, and photographs the pipe through which the laser line appears through the camera. Here, the camera unit 120 includes a camera 122 for photographing a pipe as shown in FIG. 2; A fixing part (124) for fixing the camera; And a base portion 126 for seating and supporting the fixing portion on the main board. 2 is an external perspective view schematically showing a configuration of a camera unit according to an embodiment of the present invention. Here, the camera unit 120 may be fixed at a central upper end of the main board 110 by a washer at a distance of 3 mm.

The laser scanning unit 130 is mounted on the main board 110 on the lower side of the camera unit 120 and transmits a laser beam for scanning the pipe to the pipe.

3, the laser scanning unit 130 is rotatably jig-mounted at the center of the main board 110, and has a cylindrical shape and includes a feeder (not shown) for sending a laser beam to the pipe 132); And a coupling portion 134 for coupling and fixing the ejecting portion to the main board. 3 is an external perspective view schematically showing a configuration of a laser scanning unit according to an embodiment of the present invention. Therefore, the feeding part 132 is fixed by the engaging part 134 so as to come into contact with the rotating cam 140 while being placed on the rotating cam, so that the feeding angle of the laser beam is adjusted in accordance with the rotating operation of the rotating cam And can be fixedly coupled to the main board 110 through a coupling part 134 so as to be rotatable.

The rotation cam 140 adjusts the delivery angle of the laser beam of the laser scanning unit 130 by a rotation operation. At this time, the rotation cam 140 includes an engaging portion 142 for engaging with the motor portion as shown in FIG. 4; An engaging hole 144 through which a hole is passed through the engaging portion so that the shaft of the motor is inserted; A first convex portion 146 having a convex semi-circular cross section at one side with respect to a center line in a direction perpendicular to the axial direction of the motor; And a second convex portion 148 having a convex semi-circular cross-section at half the size of the semicircular shape of the first convex portion on the other side with respect to the center line in the direction perpendicular to the axial direction of the motor. 4 is an external perspective view showing a configuration of a rotation cam according to an embodiment of the present invention. 4, the first convex portion 146 and the second convex portion 148 are formed symmetrically with respect to the center line, and the first convex portion is formed symmetrically with respect to the center line, Shaped portion having a length corresponding to the radius of the semicircular shape.

In the laser scanning unit 130, the feeding unit 132 is placed on the rotation cam 140, and the circular arc of the first convex portion 146 is moved in accordance with the rotation of the rotation cam 140 The angle of the laser beam is adjusted upward so that the second convex portion 148 reaches the point where the arc of the first convex portion 146 ends in accordance with the continuous rotation of the rotation cam, The delivery angle can be adjusted to the maximum downward angle.

The control unit 150 transmits the laser beam to the pipe through the laser scanning unit 130, captures the pipe image of the laser beam in the form of a line through the camera unit 120 at predetermined time intervals to acquire the pipe image, And processes the pipe image to control the outline of the pipe and the position and posture of the pipe.

Here, the control unit 150 may be included in the robot, but may be implemented as a control computer system that transmits and receives signals wirelessly with the robot.

In addition, the controller 150 obtains the pipe image at a predetermined time interval, calculates the coordinates of the two end points of the laser line in each frame obtained, connects the coordinates of the two end points of the laser line calculated for each frame And recognizes the two parallel straight lines obtained as a pipe outline (boundary line).

Also, the controller 150 can calculate the distance to the pipe object corresponding to the size of the pipe image.

In addition, the control unit 150 compares the previous frame and the current frame with respect to the pipe image obtained on a frame-by-frame basis at predetermined time intervals to obtain a difference image, and calculates coordinates of the two end points of the laser line through the obtained difference image , The most similar regression line can be obtained with the coordinates calculated for all the difference images and recognized as the pipe outline.

In addition, the controller 150 performs preprocessing on the pipe image obtained on a frame-by-frame basis at predetermined time intervals through Gaussian filter and canny edge detection, and preprocesses the preprocessed image through a Hough Line Transform The outline candidate group is detected, and the outline candidate groups detected for each frame are compared with each other to derive the final pipe outline.

Then, the motor unit 160 provides rotational force generated by the rotation of the motor to the rotation cam 140. Here, the motor can be implemented as a geared motor such as RA-12WGM.

5 is a flowchart illustrating a method for detecting a pipe position and posture according to an embodiment of the present invention.

As described above, in the embodiment of the present invention, the pipe position and attitude detection apparatus 100 is applied to a pipe climbing robot, and the pipe climbing robot 100 executes the pipe position and attitude detection method.

Referring to FIG. 5, in the pipe position and attitude detection apparatus 100 according to the present invention, the laser scanning unit 130 first transmits a laser beam to the pipe (S510).

Next, the camera unit 120 acquires a pipe image by photographing a pipe in which the laser beam appears in the form of a line with a camera (S520).

Then, as the rotation cam 130 is rotated by the rotational force of the motor unit 140 in the laser scanning unit 130, the delivery angle of the laser beam is adjusted (S530).

That is, the laser scanning unit 130 moves along the arc of the first convex 146 as the rotating cam 140 rotates while the feeding unit 132 is placed on the rotation cam 140 The feeding angle of the laser beam is adjusted upward so that the feeding part 132 passes the point where the arc of the first convex part 146 ends in accordance with the continuous rotation of the rotation cam 140, 148 so that the delivery angle of the laser beam is adjusted to the maximum downward angle. Since the diameter of the first convex portion 146 is two times or more larger than the diameter of the second convex portion 148, the feed portion 132 is formed on the first convex portion 146 at an upward angle When the laser beam is moved to the second convex portion 148, the delivery angle of the laser beam starts from the maximum downward angle by the difference in diameter between the first convex portion 146 and the second convex portion 148.

Next, the control unit 150 stores the pipe images obtained at predetermined time intervals through the camera unit 120 in a storage unit in step S540.

Next, the controller 150 processes the obtained pipe image to acquire the pipe outline and the position and posture (S550).

At this time, the control unit 150 obtains the pipe image at a predetermined time interval, calculates the two end point coordinates of the laser line appearing in each frame obtained, connects the two end point coordinates of the laser line calculated for each frame And the distance to the pipe object corresponding to the size of the pipe image is also calculated.

In general, it is not easy to extract the outline of a straight pipe from a camera image. Because there are objects with various linear components such as pillars, ceilings, bookshelves, and furniture in the background of pipe images, it is impossible to tell which is actually a straight line that represents the outline of the pipe we want.

Two methods are used in combination as appropriate for pipe edge detection. The first is a method of using a laser to scan the pipe surface while the line type laser scans the pipe surface and detect the outer edge of the pipe using the car image.

Accordingly, the control unit 150 compares the previous frame and the current frame with respect to the pipe image obtained on a frame-by-frame basis at predetermined time intervals to obtain a difference image, and calculates coordinates of the two end points of the laser line through the obtained difference image , The most similar regression line is obtained with the coordinates calculated for all the difference images and recognized as the pipe outline.

The second method is to detect using Hough Line Transform. That is, the control unit 150 performs preprocessing on the pipe image obtained on a frame-by-frame basis at predetermined time intervals through Gaussian filter and canny edge detection, detects the outline candidate group of the pipe through the Huff linear transformation of the preprocessed image , The outline candidates detected for each frame are compared with each other, and the final pipe outline can be derived.

In the embodiment of the present invention, a method of deriving a pipe contour is performed as shown in FIG. 6, which is a series of processes using image information obtained through a camera attached to a robot hand of the robot 100. It detects the outline of the pipe in the image and uses the position and angle information of the outline. This information is used to control the position and angle of an appropriate robot through inverse kinematics to grasp the pipe.

In the present invention, two methods are appropriately used in combination to accurately detect the outline of the pipe. By using these two methods, the detected outline is compared according to the appropriate condition, and the final outline is derived. The finally detected outline is converted into a vector form (v _x , v _y , x ₀ , y ₀ ) having four elements and transmitted to the control computer system. (v _x , v _y ) is a normalized vector of straight lines, and (x ₀ , y ₀ ) represents a point on the line.

Two types of edge detection methods using laser can be used. The first method is to wait for the laser to move from top to bottom or bottom to top and then to detect the edge (Once Detection). This is a bit more accurate because it is slow but results from a large part of the pipe. The second method is a method (real-time detection) in which the laser has previously memorized past points and derives the line to the previously stored points when receiving the edge detection command. The basic flowchart will proceed as shown in FIG.

6 is a flowchart illustrating a pipe image processing process of the controller according to the embodiment of the present invention.

Referring to FIG. 6, the control unit 150 according to the present invention acquires a pipe image through the camera unit 120 as described above (S602-Yes), and performs a preprocessing operation on the pipe image (S604).

Here, the Post Process includes operations such as Calibration, Color Convert, and Smoothing.

Since the color space is different for each device and the color reproducibility is different according to the setting, the image is calibrated by using the calibration to make the optimum state so that the color difference between the devices by a certain profile is minimized. For example, a camera mounted on a robot can be used for calibration using data values obtained by photographing check boards of various angles.

In addition, a proper Hough transform result can be obtained only through a smoothing process for removing image noise and an edge detection process before performing the Hough transform. For example, smoothing is performed using a 5x5 average filter, and the edge is detected using a Canny Edge Detector. If the edge is not detected correctly and the line due to Hough transform does not come out properly, you can adjust the threshold value.

Then, the control unit 150 checks the edge detection flag (True Detect Flag) (S606-True), and detects the laser line for each frame in the pipe image (S608).

If the detected state of the laser line is good (YES in S610), the control unit 150 sets the communication flag to the true state and the edge detection flag to the false state (S612).

Meanwhile, if the edge detection flag is in the false state (S606-False), the controller 150 executes Canny Edge Detection and Hough Line Transform (S620).

Hough line transformation is an algorithm that is easy to detect straight lines in an image. The basic algorithm can express a straight line in the x-y plane by the following equation (1), and the distance (?) And the angle (?) From the image origin are constant.

In other words, if a point is on a straight line, there will be a line that passes the point with the same (ρ, θ). Therefore, the lines passing through a point for all the pixels in the image are expressed on the ρ-θ plane. Then, curves are encountered at any one (ρ, θ), and when the number of curves to be encountered is more than a certain number, it is regarded as a straight line.

Next, the control unit 150 compares the Huff line and the laser detection line (S622).

A method of detecting a pipe edge information using a laser is a method of detecting the outline of a pipe by using a movement of a laser by constituting the laser line beam to move upward and downward constantly by using a motor and a cam. The laser line beam is scanned into the pipe, and the next frame image is compared with the next frame image to make a difference image. After that, we find the end points of both edges of the contour of the laser obtained through the car image, and find the most similar regression line with these end points and recognize it as the boundary of the pipe.

The pipe edge information detection method using the Hough Line Transform proceeds through the Gaussian filter and the Canny edge detection before the Huff transformation. Then, to detect a straight line, a Hough linear transformation is applied to detect the outline candidate group of the pipe. At this time, the threshold is changed through the number of lines. Since the pipe to be detected extends over the entire image, it is not necessary to determine whether the point on the line is a real line, and the entire edge of the pipe can be cut off due to the environment such as illumination and background, Conversion.

The outline is derived by comparing the derived outlines by two methods. In the case of using the laser, if the image has noise or the illumination is bright, the outline of the pipe can not be recognized correctly, which may cause problems. Also, in the case of the method using the Hough transform, even if there is an outline of the pipe among the detected linear candidates, there may be no reference as to which is the closest. Therefore, the outline drawn through the laser-based method is searched for the nearest Hough line and the outline is determined as the final line.

Then, if the state is good (YES in S626), the control unit 150 updates the scan line (S626). That is, an instruction to acquire the next image frame is issued.

Then, the control unit 150 transmits a signal transmission message (Emit signal send message), processes the line update flag to a false state, and sets the communication flag to a false state (S630) .

If the control unit 150 is in a return state (S632-YES), the control unit 150 returns to the initial operation and repeats the above-described process. Otherwise (S632-NO), the control unit 150 ends all the operations.

Meanwhile, the slope and the slice value are calculated for the pipe contour (boundary line) obtained by the above-described process, and the coordinate transformation equation is obtained therefrom. Then, information is transmitted to the remote control system, and through the inverse kinematics, And instructs the robot to grasp the pipe.

This will be described with reference to Figs. 7 to 9. Fig. FIG. 7 is a diagram illustrating coordinate transformation between an actual pipe image and a camera image image by a robot for climbing a pipe according to an embodiment of the present invention. FIG. FIG. 9 is a view showing a camera image after moving a hand of a robot for climbing a pipe according to an embodiment of the present invention. FIG.

The robot 100 for pipe climbing recognizes the pipe which is originally stably gripped among a plurality of pipes as a base portion and senses the position and attitude of an adjacent pipe to be moved.

At this time, the position conversion matrix formula between the base portion of the robot 100 for climbing the pipe and the pipe to be gripped can be briefly expressed by the following Equation (2).

θ ₁ , θ ₂ , θ ₃ , θ ₄ , θ ₅ represent the current joint angles between the respective links.

Therefore, if only the position conversion matrix formula between the camera 122 and the pipe of the camera unit 120 is determined, the position conversion matrix between the base part of the robot 100 for pipe climbing and the pipe to be moved can be determined. The position / attitude conversion equation between the camera and the pipe can be expressed by the following equation (3).

을 단순화하기 위해 아래 3가지를 가정할 수 있다.Here, the position / posture conversion equation between the camera 122 and the pipe

The following three can be assumed.

First, the actual pipe is in the form of a three-dimensional cylinder, but it can be assumed to be a flat rectangular shape.

Second, the pipe is assumed to be cylindrical and symmetrical about the z-axis. Thus, we can simplify the pipe angle φ _z to zero.

Third, it is assumed that when the pipe climbing robot 100 grasps a pipe, it can be held anywhere on the pipe center line. That is, the Z _pipe is not important when the robot catches the _pipe , and the pipe coordinate system can be set with D _{z set} to zero.

을 다음 수학식 4와 같이 단순화 할 수 있다. In the above three assumptions, the position / posture conversion equation between the camera 122 and the pipe

Can be simplified as shown in Equation (4).

Here, in order to obtain the position / posture conversion equation between the camera 122 and the pipe, only four unknowns D _x , D _y , φ _x , and φ _y need to be considered. In other words, only the four unknowns of the x-axis displacement, the y-axis displacement, the rotation angle around the x-axis, and the rotation angle around the y-

7, the relationship between the point Q on the actual pipe manifold 10 and the expected P in the image plane 11 is calculated by the following mathematical expression Expression 5 is expressed as follows.

If this is solved, it can be expressed as the following equation (6).

In Equations 5 and 6, the determinant G is a perspective transformation matrix, and the variable f represents the focal length of the camera.

Referring to Figs. 7-9, when viewing the pipe through the camera 122, the shape of the actual pipe is projected onto the image plane 11 in a trapezoidal shape. A straight line at both ends in the pipe plane appears as an oblique slant with a slope of A ₀ and an x intercept of C ₀ .

이고, 우측단을 구성하는 직선의 방정식은

이다.That is, the equation of the straight line constituting the left end in the trapezoidal pipe projected on the image plane 11

, And the equation of the straight line constituting the right end is

to be.

Here, A ₀ representing the slope can be calculated by the following equation (7).

Here, C ₀ representing the x-intercept can be calculated by the following equation (8).

와

, x절편

및

를 구할 수 있다.That is, the control unit 150 controls the inclination

Wow

, x intercept

And

Can be obtained.

,

,

,

가 포함된 네 개의 방정식이 나오고, 이 네 개의 비선형 연립방정식을 풀면, 우리가 원하는 미지수 위해 D_x, D_y, φ_x, φ_y를 구할 수 있게 된다.Finally, with four unknowns,

,

,

,

And solving these four nonlinear simultaneous equations, we can find D _x , D _y , φ _x , and φ _y for the unknown we want.

Finally, this value is substituted into Equation (2) to obtain the position conversion matrix equation between the base portion and the pipe of the robot 100 for pipe climbing, and the joint angles? ₁ ,? ₂ ,? ₃ ,? ₄ , and θ ₅ can be obtained.

However, to solve the four nonlinear simultaneous equations, it is necessary to use numerical calculations, which can take a lot of time to control the robot joints.

,

,

,

)은 다음 수학식 9와 같은 연관 관계가 있다. Therefore, we can propose the following method to obtain four unknowns D _x , D _y , φ _x , and φ _y . The four unknowns D _x , D _y , φ _x , and φ _y are the slope of the projected slope and the intercepts (

,

,

,

) ≪ / RTI >

Therefore, the controller 150 can calculate the unknowns D _x , D _y , φ _x , and φ _y using the following Equation (10).

Here, k is a sampling time, K _DX is a gain determined experimentally, and (k-1) represents a value immediately before.

In this way, the unknowns D _x , D _y , φ _x , and φ _y are determined, and this value is substituted into the equation (2) to obtain the position conversion matrix between the base of the robot 100 for pipe climbing and the pipe to be moved. Through the kinematics, joint angles θ ₁ , θ ₂ , θ ₃ , θ ₄ , θ ₅ of the robot are obtained.

Accordingly, the control unit 150 drives the joint motor to control the operation of the robot 100 for pipe climbing with the angles? ₁ ,? ₂ ,? ₃ ,? ₄ ,? ₅ between the links .

As described above, according to the present invention, in an environment in which a robot or a pipe climbing a pipe is cut and processed, an image of the pipe is obtained through a camera and a laser attached to the robot hand, and then the slope of the pipe outline It is possible to increase the productivity by omitting the guide lane installation work which is indispensable for automatic welding of pipes by providing the position data necessary for the work by calculating the position data required for the work by detecting the position of any nearby pipe using the slice value, It is possible to realize a pipe position and posture detecting device and a pipe position and posture detecting method using the same to enable a hand to properly catch peripheral pipes for work in accordance with the pipe shape.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. Only. It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. .

100: Pipe position and posture detection device 110: Main board
120: camera unit 122: camera
124: fixing part 126: base part
130: laser scanning unit 132:
134: engaging portion 140: rotation cam
142: engaging portion 144: engaging hole
146: first convex portion 148: second convex portion
150: control unit 160: motor unit

Claims (14)

An apparatus for detecting a position and a pose of a pipe to be moved in a workplace where one or more pipes are connected to each other,
A main board;
A camera unit mounted on the main board and having a camera for photographing the pipe;
A laser scanning unit mounted on the main board on a lower side of the camera unit, for scanning the pipe by sending a laser beam to the pipe;
A rotation cam for adjusting a delivery angle of the laser beam of the laser scanning unit by a rotation operation;
A motor part for providing a rotational force to the rotation cam in accordance with rotation of the motor; And
A laser beam is transmitted to the pipe through the laser scanning unit, a pipe image in which a laser beam appears in a line form is photographed through the camera unit at a predetermined time to acquire a pipe image, and the obtained pipe image is processed, And a pose;
And a pipe position and attitude detection device.
The method according to claim 1,
The rotation cam
A coupling part for coupling to the motor part;
A coupling hole through which the shaft of the motor is inserted into the coupling portion;
A first convex portion having a convex semi-circular cross section at one side with respect to a center line in a direction perpendicular to the axial direction of the motor; And
A second convex portion having a convex semi-circular cross-section at half the size of the semicircular shape of the first convex portion on the other side with respect to a center line in a direction perpendicular to the axial direction of the motor;
And a position detector for detecting the position of the pipe.
3. The method of claim 2,
Wherein the first convex portion and the second convex portion are formed symmetrically with respect to the center line in the rotation cam, and the other portion of the first convex portion, which is not symmetrical with the second convex portion, Wherein the first and second sides of the pipe form a rectangular surface having two sides corresponding to the length of the pipe.
3. The method of claim 2,
The laser scanning unit includes:
A delivery portion having a cylindrical shape and delivering a laser beam to the pipe; And
An engaging portion for fixing and connecting the dispensing portion to the main board;
Lt; / RTI >
Wherein the feeding portion is fixed by the coupling portion so as to contact the rotation cam while being placed on the rotation cam so that the feeding angle of the laser beam is adjusted according to the rotation operation of the rotation cam, And is fixedly coupled to the main board through the second connector.
5. The method of claim 4,
Wherein the feeder is lifted up along the arc of the first convex portion in accordance with the rotation of the rotation cam so that the feed angle of the laser beam is adjusted upward, Wherein the second convex portion is in contact with the second convex portion so that the dispensing angle of the laser beam is adjusted to the maximum downward angle when passing the point where the arc of the first convex portion ends according to the continuous rotation operation of the rotation cam. .
The method according to claim 1,
The camera unit includes:
A camera for photographing the pipe;
A fixing unit for fixing the camera; And
A base portion for seating and supporting the fixing portion on the main board;
And a position detector for detecting the position of the pipe.
The method according to claim 1,
The control unit obtains the pipe image at a predetermined time interval for the pipe image, calculates two end point coordinates of the laser line appearing in each frame obtained, and connects the two end point coordinates of the laser line calculated for each frame And a distance between the pipe object and the pipe object corresponding to the size of the pipe image is calculated.
8. The method of claim 7,
Wherein the control unit compares the previous frame and the current frame with respect to the pipe image obtained at the predetermined time intervals to obtain a difference image, calculates coordinates of the two end points of the laser line through the obtained difference image, And acquires the most similar regression line with the coordinates calculated for the difference image to recognize the pipe as the pipe outline.
8. The method of claim 7,
The control unit performs preprocessing on the pipe image obtained on a frame-by-frame basis at predetermined time intervals through Gaussian filter and canny edge detection, and outputs the preprocessed image to the outline candidate group of the pipe through a Hough Line Transform And comparing the detected outline candidates for each frame to derive a final pipe outline.
(a) delivering a laser beam to a laser scanning section pipe;
(b) capturing a pipe, in which the camera unit displays the line of the laser beam, with a camera to obtain a pipe image;
(c) adjusting the feeding angle of the laser beam as the rotating cam rotates by the rotational force of the motor unit in the laser scanning unit;
(d) storing, by a frame, the pipe image obtained by the control unit at predetermined time intervals through the camera unit;
(e) the control unit processes the obtained pipe image to obtain a pipe outline and a position and a pose;
Wherein the pipe position and posture detection method comprises:
11. The method of claim 10,
In the step (c), the laser scanning unit may be lifted up along the arc of the first convex portion in accordance with the rotation operation of the rotation cam while the delivery unit is placed on the rotation cam, And the delivery portion is brought into contact with the second convex portion so that the delivery angle of the laser beam is adjusted to the maximum downward angle by passing the point where the arc of the first convex portion ends in accordance with the continuous rotation operation of the rotation cam , Pipe location and attitude detection method.
11. The method of claim 10,
In the step (e), the controller obtains the pipe image at a predetermined time interval, calculates the coordinates of the two end points of the laser line in each of the obtained frames, and calculates two end points of the laser line calculated for each frame The two parallel straight lines obtained by connecting the coordinates are recognized as a pipe outline and the distance between the pipe object and the pipe object corresponding to the size of the pipe image is calculated.
13. The method of claim 12,
In the step (e), the controller compares the previous frame and the current frame with respect to the pipe image obtained in units of frames at the predetermined time intervals to obtain a difference image, And obtaining the most similar regression line with the calculated coordinates for all the difference images and recognizing the pipe line as the pipe outline.
13. The method of claim 12,
In the step (e), the controller may perform preprocessing on a pipe image obtained on a frame-by-frame basis at predetermined time intervals through Gaussian filter and canny edge detection, and perform Hough Line Transform And detecting a candidate outline of the pipe through each of the frames and comparing the detected outline candidates for each frame to derive a final pipe outline.

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