Pipe inspection robot and pipe inspection method

Abstract

The present invention relates to a pipe inspection robot which can inspect the internal condition of a pipe by capturing an image of the inside of the pipe while entering and moving in the pipe. An embodiment of the present invention relates to a pipe inspection robot for inspecting the internal condition of a pipe. The pipe inspection robot comprises: a body having a battery and a control device for estimating the position of the pipe inspection robot and adjusting the position and movement direction of the pipe inspection robot; a camera unit in which heterogeneous cameras for capturing an image of the inside of a pipe are combined; and a front wheel unit and a rear wheel unit, which are each a pair of wheels capable of independently rotating on the left and right sides of the front end and the rear end of the body.

Description

Robot for pipe inspection and inspection method thereof

[0001] The present invention relates to a robot for pipe inspection and an inspection method thereof, and more particularly, to a robot for pipe inspection and an inspection method thereof capable of inspecting the condition of the inside of a pipe by capturing the inside of the pipe while entering and moving inside the pipe.

[0002] In general, bridges for the passage of people, vehicles, etc. can be installed in terrain that cuts off passageways, such as rivers and valleys, as needed, and pipes that function as irrigation channels can be installed in bridges as needed. Pipes installed in such bridges are called bridge-added pipes.

[0003] These bridge-added pipes must be inspected periodically and maintained accordingly. This periodic inspection is common to all pipes installed in buildings, not just bridge-added pipes. However, due to various reasons such as the location of the bridge installation, the height of the building or bridge, and the length of the bridge, it is difficult for workers to access them.

[0004] Accordingly, there is a trend of proposing inventions related to robots for pipe inspection that can be equipped with inspection equipment and inspect pipes in place of workers, and inventions related to robots for pipe inspection have been proposed and published, including "Mobile robot for external inspection of pipes" in Korean Patent Publication No. 10-1281255, "Pipe inspection robot" in Korean Patent Publication No. 10-1292999, "Method for controlling pipe climbing robot" in Korean Patent Publication No. 10-1323452, and "Robot for inspecting pipe condition" in Korean Patent Publication No. 10-1430251.

[0005] However, the above-mentioned conventional technologies have the problem that it is difficult to conduct a free and detailed inspection of the pipes using only images taken by the robot, so there is a need for an invention regarding a device such as a robot that can conduct a detailed inspection of the pipes.

[0006] Prior art literature

[0007] Patent documents

[0008] Republic of Korea Patent No. 10-1281255 (registered on June 26, 2013)

[0009] Republic of Korea Patent No. 10-1292999 (registered on July 29, 2013)

[0010] Republic of Korea Patent No. 10-1323452 (registered on October 23, 2013)

[0011] Republic of Korea Patent No. 10-1430251 (registered on August 7, 2014)

[0012] Accordingly, the present invention has been devised to solve the above-mentioned problems, and the purpose of the present invention is to provide a robot for pipe inspection and an inspection method thereof, which can precisely capture the inside of a pipe that is difficult for a worker to access through a camera unit that combines a multi-camera module having multiple RGB cameras and a heterogeneous camera such as a PTZ camera, and closely inspect the condition of the inside of the pipe.

[0013] However, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0014] As a technical means for achieving the above object, a pipe inspection robot according to one embodiment of the present invention is a pipe inspection robot for inspecting the internal state of a pipe, wherein the pipe inspection robot may include a main body having a battery, a control device for estimating the position of the pipe inspection robot and controlling the position and movement direction of the pipe inspection robot; a camera unit in which different types of cameras are combined for capturing the inside of the pipe; and a front wheel unit and a rear wheel unit which are a pair of wheels capable of independently rotating on the left and right sides of the front and rear ends of the main body, respectively.

[0015] In addition, the camera unit may include a multi-camera module comprising a plurality of RGB cameras that photograph the inside of the pipe to capture a front measurement image; an angle adjustment hinge for adjusting the angles of the plurality of RGB cameras; a camera housing that accommodates the multi-camera module coupled to the angle adjustment hinge therein, the camera housing having one side and the other side open and an opening formed on the side; a PTZ camera coupled to one side of the camera housing to close one side of the camera housing, and that captures a precise measurement image by enlarging and photographing a specific area inside the pipe; a cover unit coupled to the other side of the camera housing to close the other side of the camera housing; a lens unit made of a transparent material coupled to the opening and comprising a plurality of lenses for protecting the plurality of RGB cameras; and an LED light that provides light so that the plurality of RGB cameras can capture the front measurement image.

[0016] And the camera continuously collects a front measurement image through the multi-camera module and a precision measurement image through the PTZ camera, respectively, and transmits them to the control device, and the control device assigns a time stamp to the front measurement image and the precision measurement image to synchronize them temporally and match images at the same time, and detects feature points of the front measurement image and the precision measurement image based on a feature point detection algorithm, and then estimates a relationship between the front measurement image and the precision measurement image by matching the feature points, and calculates a transformation matrix between the front measurement image and the precision measurement image based on the feature point matching, and then calculates a geometric transformation so that the precision measurement image is aligned to the front measurement image, and then superimposes the aligned precision measurement image on the front measurement image and then converts it based on a blending technique to synthesize the front measurement image and the precision measurement image, and continuously updates and synthesizes the front measurement image and the precision measurement image to create a composite image.

[0017] In addition, the control device removes noise from the composite image, then performs edge detection to emphasize the boundary of the pipe, converts points of the composite image in which the boundary of the pipe is emphasized through noise removal and edge detection into a parameter space to detect multiple straight lines, and then uses the straight lines to detect the boundary line of the pipe, calculates the center point of the detected straight line to detect the center inside the pipe, and then determines the center coordinates according to the center, calculates the error between the current position of the pipe inspection robot and the center coordinates of the pipe, and then adjusts the position and movement direction of the pipe inspection robot and the shooting angle of the camera according to the calculated error, and continuously adjusts the position and movement direction of the pipe inspection robot and the shooting angle of the camera based on the composite image collected in real time from the camera, and controls the pipe inspection robot to move along the center of the pipe inside the pipe through repeated feedback.

[0018] And the camera, the plurality of RGB cameras continuously photograph the inside of the pipe while the pipe inspection robot moves in one direction inside the pipe to obtain a portion of the pipe image and then transmit the image to the control device, and the control device corrects the distortion of the portion of the pipe image and then converts the distortion-corrected portion of the pipe image into a plane, and can create a single image of the inside of the pipe by connecting the portion of the pipe images converted into planes.

[0019] In addition, the control device can control the pipe inspection robot to move in the one direction while generating the pipe interior image when the pipe interior image is generated for the first time after the pipe inspection robot enters the interior of the pipe.

[0020] And, when the control device generates the pipe internal image and there are two or more pipe internal images generated to date, the control device calculates a matching point between each pipe internal image based on an overlapping area of ​​each pipe internal image generated to date using a matching algorithm, and connects the multiple pipe internal images based on the matching point to synthesize them into one continuous front measurement image.

[0021] In addition, the control device includes a first encoder, which is a reel counter, for estimating a current position of the pipe inspection robot based on the rotational speed of cable reels provided in the front and rear wheel sections, respectively; a second encoder, which is a wheel counter, for estimating a current position of the pipe inspection robot based on the rotational speed of the front and rear wheel sections; a data combining unit for primarily determining a current position of the pipe inspection robot by combining the current position information of the pipe inspection robot estimated by the first encoder and the current position information of the pipe inspection robot estimated by the second encoder; a data calculating unit for calculating a moving distance of the pipe inspection robot by analyzing a frame of a front measurement image transmitted from the multi-camera module based on a visual odometer technique, and for tracking the movement of the pipe inspection robot by matching feature points between frames of consecutive front measurement images to calculate a moving direction and distance of the pipe inspection robot; And it may include a position estimation unit that finally estimates the current position of the pipe inspection robot based on the current position information of the pipe inspection robot transmitted from the data combination unit and the movement direction and distance information of the pipe inspection robot transmitted from the data calculation unit.

[0022] And the front wheel part and the rear wheel part may include a tire; a tire mount bracket that is fitted to the tire and houses a driving part for driving the front wheel part and the rear wheel part therein; a sealing cap that is coupled to the tire mount bracket and prevents the driving part from being separated from the tire mount bracket; a waterproof / heat dissipating housing that is coupled to the sealing cap and prevents water and moisture from penetrating the inside of the pipe into the driving part and simultaneously dissipates heat generated from the driving part to the outside of the tire mount bracket; a hub having a communication / power connector provided on one side so that the driving part receives power from the battery and receives a control signal from the control device; and a fixing bracket that fixes the tire mount bracket so that it is maintained in a state where it is fitted to the tire.

[0023] Additionally, the driving unit may be an in-wheel type modular unit accommodated on the inside of the tire mount bracket.

[0024] The present invention enables a camera unit that combines a multi-camera module equipped with multiple RGB cameras and a PTZ camera to precisely capture the inside of a pipe that is difficult for workers to access, thereby allowing a close inspection of the condition inside the pipe.

[0025] However, the effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0026] FIG. 1 is a drawing illustrating the structure of a robot for pipe inspection according to one embodiment of the present invention.

[0027] Figure 2 is an exploded perspective view of a camera unit according to one embodiment of the present invention.

[0028] FIG. 3 is a drawing showing an example of a front measurement image and a precision measurement image according to one embodiment of the present invention.

[0029] FIG. 4 is a flowchart illustrating a process of a composite image collection method using a camera unit according to one embodiment of the present invention.

[0030] FIG. 5 is a flowchart illustrating a process of a high-speed pipe inspection method using a multi-camera module according to one embodiment of the present invention.

[0031] Figure 6 is a flowchart illustrating a process of a robot direction control method for pipe inspection according to one embodiment of the present invention.

[0032] Figure 7 is a drawing to explain the difference between a robot for pipe inspection when direction control is not applied and when it is applied.

[0033] FIG. 8 is a block diagram illustrating a control device and a device constituting the control device according to one embodiment of the present invention.

[0034] Figure 9 is an exploded perspective view of a front wheel according to one embodiment of the present invention.

[0035] FIG. 10 is a block diagram illustrating a driving unit and a device constituting the driving unit according to one embodiment of the present invention.

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. However, the description of the present invention is merely an embodiment for structural and functional explanation, and therefore the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, since the embodiments can be modified in various ways and can have various forms, the scope of the present invention should be understood to include equivalents that can realize the technical idea. In addition, the purposes or effects presented in the present invention do not mean that a specific embodiment must include all of them or only such effects, and therefore the scope of the present invention should not be construed as being limited thereby.

[0037] The meanings of terms described in the present invention should be understood as follows.

[0038] Terms such as "first" and "second" are intended to distinguish one component from another, and the scope of the rights should not be limited by these terms. For example, a first component could be referred to as a second component, and similarly, a second component could also be referred to as a first component. When a component is referred to as being "connected" to another component, it should be understood that it may be directly connected to that other component, but there may also be other components in between. Conversely, when a component is referred to as being "directly connected" to another component, it should be understood that there are no other components in between. Meanwhile, other expressions describing the relationship between components, such as "between" and "immediately between" or "adjacent to" and "directly adjacent to", should be interpreted similarly.

[0039] Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "comprises" or "has" should be understood to specify the presence of stated features, numbers, steps, operations, components, parts, or combinations thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0040] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted to be consistent with their meaning within the context of the relevant technology, and should not be interpreted as having ideal or overly formal meanings unless explicitly defined herein.

[0041] Structure of a robot for pipe inspection

[0042] Hereinafter, the configuration of a preferred embodiment will be described in detail with reference to the attached drawings.

[0043] FIG. 1 is a drawing illustrating the structure of a robot for pipe inspection according to one embodiment of the present invention.

[0044] Referring to FIG. 1, a robot (100) for pipe inspection according to one embodiment of the present invention is a robot for inspecting the internal state of a pipe (10) that is difficult for a worker to access, and includes a main body (110), a camera unit (120), a front wheel unit (130), and a rear wheel unit (140).

[0045] In one embodiment, the main body (110) may be equipped with (built-in) a battery (not shown) for the operation of the camera unit (120), front wheel unit (130), and rear wheel unit (140), although not shown in the drawing.

[0046] In addition, the main body (110) may be provided with a front wheel steering unit (111) and a rear wheel steering unit (112) on one side (front) and the other side (rear) for rotating and tilting the front wheel (130) and the rear wheel (140), respectively.

[0047] And the main body (110) may be equipped with an anti-overturning module (113) to prevent the pipe inspection robot (100) from tipping over while moving along the inside of the pipe (10).

[0048] In one embodiment, the rollover prevention module (113) collects sensor data including the angular velocity and acceleration of the pipe inspection robot (100) collected through a gyroscope (not shown) and an accelerometer (not shown) built into the main body (110), and then confirms that the center of gravity of the pipe inspection robot (100) is in contact with the bottom surface of the pipe (10) at all of the plurality of support points (preferably, tires of the front wheel (130) and the rear wheel (140) that are in contact with the bottom surface of the pipe (10), and then tilts the front wheel (130) and / or the rear wheel (140) through linkage with the front wheel steering unit (111) and the rear wheel steering unit (112) so that the balance of the pipe inspection robot (10) is maintained inside the pipe (10).

[0049] In addition, the main body (110) may be equipped with (built-in) a control device (115) for estimating the position of the pipe inspection robot (100) inside the pipe (10) and controlling the position and movement direction of the pipe inspection robot (100).

[0050] In one embodiment, the control device (115) can control the front wheel steering unit (111) and the rear wheel steering unit (112) to move the pipe inspection robot (100) in one direction (forward) or the other direction (rearward).

[0051] The camera unit (120) is provided on the front side of the pipe inspection robot (100) to photograph the front of the pipe inspection robot (100).

[0052] In one embodiment, the camera unit (120) may be a device in which heterogeneous cameras, such as a multi-camera module (121) and a PTZ camera (122), are combined to precisely capture the inside of a pipe (10).

[0053] The front wheel (130) and the rear wheel (140) are provided on the left and right sides of the front and rear ends of the main body (110), and are a pair of wheels (wheels) that can be independently rotated and rotated by the front wheel steering unit (111) and the rear wheel steering unit (112) so that the pipe inspection robot (100) that has entered the interior of the pipe (10) moves in one direction (forward) or the other direction (rear).

[0054] In one embodiment, the front wheel (130) may be a wheel that has a steering function so that the pipe inspection robot (100) moves in a movement direction controlled by the control device (115).

[0055] In one embodiment, the rear wheel (140) may be a wheel that provides propulsion to the pipe inspection robot (100) so that the pipe inspection robot (100) moves forward in one direction (forward) or backward in the other direction (rearward) inside the pipe (10).

[0056] In one embodiment, the front wheel (130) and the rear wheel (140) may be tilted up and down by the rollover prevention module (113) so as not to come into contact with the bottom surface of the pipe (10) or to prevent the robot (100) for pipe inspection from being impeded from moving due to contact with a tall obstacle (e.g., accumulated foreign matter, etc.) generated on the bottom surface of the pipe (10).

[0057] That is, the robot (100) for pipe inspection can avoid obstacles created on the bottom surface of the pipe (10) while checking the internal condition of the pipe (10) by vertical tilting of the front wheel (130) and the rear wheel (140) and can drive along the bottom surface of the pipe (10) by making contact with the bottom surface of the pipe (10).

[0058] Camera section structure

[0059] Below, the structure of the camera unit (120) that captures the inside of the pipe (10) of the pipe inspection robot (100) will be described in detail.

[0060] FIG. 2 is an exploded perspective view of a camera unit according to one embodiment of the present invention, and FIG. 3 is a drawing showing an example of a front measurement image and a precision measurement image according to one embodiment of the present invention.

[0061] Referring to FIG. 2, the camera unit (120) may be equipped with a multi-camera module (121) and a PTZ camera (122), which are heterogeneous cameras for capturing the inside of the pipe (10).

[0062] In one embodiment, the multi-camera module (121) operates via a battery (not shown) built into the main body (110) to capture the inside of the pipe (10) via multiple cameras, thereby capturing a front measurement image (1210) as shown in FIG. 3.

[0063] At this time, the number of multiple cameras is not limited, but in one embodiment, they may be first to fourth RGB cameras (121a to 121d), and the first to fourth RGB cameras (121a to 121d) can capture a front measurement image (1210) by photographing the inside of the pipe (10) while being attached to an angle adjustment hinge (123) that can adjust a specific angle and offset on the camera unit (120).

[0064] That is, the multi-camera module (121) can capture a front measurement image (1210) by combining images of the inside of the pipe taken by each RGB camera (121a to 121d).

[0065] In one embodiment, the PTZ camera (122) operates through a battery (not shown) built into the main body (110), is positioned in front of the multi-camera module (121) due to the structure of the camera unit (120), and captures a precise measurement image (1220) by enlarging a specific area inside the pipe (10) and then taking a picture through an optical zoom or digital zoom function, as shown in FIG. 3.

[0066] In addition, the PTZ camera (122) is equipped with a pan for horizontal rotation and a tilt for vertical rotation for angle adjustment, so that it can capture a precise measurement image (1220) by photographing a specific area inside the pipe (10) from various angles.

[0067] In one embodiment, the camera unit (120) is a combination of heterogeneous cameras, such as a multi-camera module (121) composed of 1st to 4th RGB cameras (121a to 121d) and a PTZ camera (122), and based on a composite image combining a front measurement image (1210) and a precision measurement image (1220) measured from each camera, the interior of a pipe (10) that is difficult for a worker to access can be closely inspected.

[0068] This camera part (120) may further be equipped with an angle adjustment hinge (123), a camera housing (124), a lens part (125), an LED light (126), and a cover part (127).

[0069] In one embodiment, the angle adjustment hinge (123) is coupled with the multi-camera module (121) to adjust the angles of the first to fourth RGB cameras (121a to 121d) constituting the multi-camera module (121).

[0070] In one embodiment, the camera housing (124) accommodates a multi-camera module (121) therein in combination with an angle adjustment hinge (123), and one side and the other side are opened respectively to accommodate the multi-camera module (121), and one side can be closed when combined with a PTZ camera (122), and the other side can be closed when combined with a cover (127).

[0071] In one embodiment, the lens unit (125) is coupled to an opening formed in a side portion of the camera housing (124), and can protect the first to fourth RGB cameras (121a to 121d) accommodated inside the camera housing (124) from water, moisture, falling foreign substances, etc. inside the pipe (10), and can be made of a transparent material so that the first to fourth RGB cameras (121a to 121d) can photograph the inside of the pipe (10).

[0072] Since the multi-camera module (121) is composed of 1st to 4th RGB cameras (121a to 121d), it is preferable that a plurality of openings be formed in the camera housing (124), and thus the lens unit (125) may be composed of 1st to 4th lenses (125a to 125d) that can be connected to each opening.

[0073] In one embodiment, the LED light (126) can be operated by a battery (not shown) built into the main body (110) so that the first to fourth RGB cameras (121a to 121d) constituting the multi-camera module (121) can capture a front measurement image (1210) by photographing the inside of the pipe (10) in a dark environment.

[0074] That is, the first to fourth RGB cameras (121a to 121d) can capture the inside of the pipe (10) through the light provided by the LED light (126), and the front measurement image (1210) captured by the first to fourth RGB cameras (121a to 121d) is affected by the light provided by the LED light (126).

[0075] In one embodiment, the cover portion (127) can be coupled to the open side of the camera housing (124) to close the other side of the camera housing (124).

[0076] In addition, the cover part (127) not only serves as a cover for the camera housing (124), but also allows the camera part (120) to be fastened (joined) to the main body part (110) through a fastening means provided on the other side opposite to the one side facing the internal space of the camera housing (124).

[0077] Composite image collection method

[0078] Below, the process of the composite image collection method (S10) using the above-described camera unit (120) will be described in detail.

[0079] FIG. 4 is a flowchart illustrating a process of a composite image collection method using a camera unit according to one embodiment of the present invention.

[0080] Referring to FIG. 4, the composite image collection method (S10) may proceed in the following order: data collection step (S11), image synchronization step (S12), image alignment and matching step (S13), and image synthesis and composite image creation step (S14).

[0081] In the above data collection step (S11), the camera unit (120) can continuously collect a front measurement image (1210) and a precision measurement image (1220) by taking pictures of the inside of the pipe (10) using the first to fourth RGB cameras (121a to 121d) and the PTZ camera (122) constituting the multi-camera module (121) after the pipe inspection robot (100) enters the inside of the pipe (10).

[0082] In the above image synchronization step (S12), the camera unit (120) continuously transmits the collected front measurement image (1210) and precision measurement image (1220) to the control device (115), and the control device (115) assigns a time stamp to each of the front measurement image (1210) and precision measurement image (1220) transmitted in real time to synchronize them temporally and then match the images at the same point in time.

[0083] In the above image alignment and matching step (S13), the control device (115) detects feature points of the front measurement image (1210) and the precision measurement image (1220) based on a feature point detection algorithm (e.g., SIFT, SURF algorithm), and then matches the feature points to estimate the relationship between the front measurement image (1210) and the precision measurement image (1220).

[0084] Additionally, the control device (115) can calculate a transformation matrix (e.g., homography) between the front measurement image (1210) and the precision measurement image (1220) based on the feature point matching, and then calculate a geometric transformation so that the precision measurement image (1220) is aligned to an appropriate position of the front measurement image (1210).

[0085] In the image synthesis step among the image synthesis and composite image generation steps (S14) above, the control device (115) can superimpose the aligned precision measurement image (1220) on the front measurement image (1210) and synthesize the front measurement image (1210) and the precision measurement image (1220) by switching based on a blending technique (e.g., alpha blending, pyramid blending, etc.).

[0086] In the composite image generation step among the above image synthesis and composite image generation steps (S14), the control device (115) can continuously update and synthesize the front measurement image (1210) and the precision measurement image (1210) to generate a composite image, and can update the composite image by reflecting the movement and zoom operation of the PTZ camera (122).

[0087] High-speed pipe inspection method

[0088] Below, the process of the pipe high-speed inspection method (S20) using the above-described multi-camera module (121) will be described in detail.

[0089] FIG. 5 is a flowchart illustrating a process of a high-speed pipe inspection method using a multi-camera module according to one embodiment of the present invention.

[0090] Referring to FIG. 5, the pipe high-speed inspection method (S20) may proceed in the following order: a movement step (S21), a focus adjustment step (S22), a continuous shooting and pipe partial image acquisition step (S23), a pipe internal image generation step (S24), and a front measurement image synthesis step (S25).

[0091] In the above movement step (S21), the robot (100) for pipe inspection can enter and start moving inside the pipe (10) through the control of the control device (115).

[0092] At this time, the control device (115) can receive a signal from a terminal (e.g., smartphone, PC, tablet, etc.) provided by the manager of the pipe inspection robot (100) and control the pipe inspection robot (100) to enter and move into the interior of the pipe (10).

[0093] In the above focus adjustment step (S22), the control device (115) can adjust the focus of the first to fourth RGB cameras (121a to 121d) constituting the multi-camera module (121) so that the interior of the pipe (10) can be photographed by the first to fourth RGB cameras (121a to 121d).

[0094] In the above continuous shooting and pipe part image acquisition step (S23), the first to fourth RGB cameras (121a to 121d) constituting the multi-camera module (121) can continuously capture the inside of the cylindrical pipe (10) while moving in one direction (forward) to acquire a pipe part image.

[0095] In the above pipe internal image generation step (S24), the first to fourth RGB cameras (121a to 121d) transmit the acquired pipe part images to the control device (115), and the control device (115) corrects the distortion of the pipe part images received, converts the distortion-corrected pipe part images into a plane, and connects the pipe part images converted into planes to generate one pipe internal image.

[0096] At this time, if the pipe inspection robot (100) enters the inside of the pipe (10) and an image of the inside of the pipe is generated for the first time, the control device (115) can control the pipe inspection robot (100) to move in one direction (forward) while generating the image of the inside of the pipe.

[0097] In this way, the pipe internal image generation step (S24) for generating a pipe internal image and the movement step (S21) for generating the next pipe internal image to be connected to the pipe internal image can be performed simultaneously until the process of synthesizing a front measurement image (1210) based on connecting a plurality of pipe internal images is completed.

[0098] In contrast, if the number of internal pipe images generated to date is two or more due to the internal pipe image being generated in the internal pipe image generation step (S24), the control device (115) can perform a front measurement image synthesis step (S25) of synthesizing the multiple internal pipe images into a front measurement image (1210).

[0099] In the above front measurement image synthesis step (S25), the control device (115) calculates a matching point between each pipe internal image based on the overlapping area of ​​each pipe internal image generated up to now using a matching algorithm, and connects the multiple pipe internal images based on the matching point to synthesize them into one continuous front measurement image (1210).

[0100] This high-speed pipe inspection method (S20) is a method for synthesizing a front measurement image (1210), and is also a method for the multi-camera module (121) of the present invention to capture the front measurement image (1210).

[0101] Robot direction control method for pipe inspection

[0102] Below, the process of the pipe inspection robot direction control method (S30) for controlling the movement direction of the pipe inspection robot (100) will be described in detail.

[0103] FIG. 6 is a flowchart illustrating a process of a method for controlling the direction of a robot for pipe inspection according to one embodiment of the present invention, and FIG. 7 is a drawing for explaining the difference between a state in which the direction of a robot for pipe inspection is not applied and a state in which the direction is applied.

[0104] Referring to Fig. 6, the robot direction control method for pipe inspection (S30) may proceed in the following order: a composite image preprocessing step (S31), a straight line detection step (S32), a center point calculation and center coordinate determination step (S33), an error calculation and direction control step (S34), and a real-time feedback and adjustment step (S35).

[0105] In the above composite image preprocessing step (S31), the control device (115) can remove noise from a composite image that combines a front measurement image (1210) and a precision measurement image (1220), and emphasize the boundary of the pipe (10) through edge detection within the composite image.

[0106] At this time, the control device (115) can remove noise from the composite image based on Gaussian blur, Median filter, etc.

[0107] Additionally, the control device (115) can emphasize the boundary of the pipe (10) within the composite image using a Canny edge detector or the like.

[0108] In the above straight line detection step (S32), the control device (115) converts points of a composite image in which the boundary of the pipe (10) is emphasized into a parameter space through noise removal and edge detection based on the Hough transform method to detect multiple straight lines (1151), and can detect the boundary line of the pipe (10) using the straight lines (1151).

[0109] At this time, the boundary line of the pipe (10) means a line forming the interior of the pipe (10) among the plurality of detected straight lines (1151).

[0110] In the above center point calculation and center coordinate determination step (S33), the control device (115) can calculate the center point of the detected straight line to detect the center (1152) inside the pipe (10) and determine the center coordinate according to the center (1152).

[0111] In the above error calculation and direction control step (S34), the control device (115) calculates the error between the current position of the pipe inspection robot (100) and the center coordinates of the pipe (10), and can adjust the position and movement direction of the pipe inspection robot (100) and the shooting angle of the camera unit (120) according to the calculated error.

[0112] In the above real-time feedback and adjustment step (S35), the control device (115) can continuously adjust the position and movement direction of the pipe inspection robot (100) and the shooting angle of the camera unit (120) based on the composite image collected in real time from the camera unit (120), and through this repetitive feedback loop, the pipe inspection robot (100) can be controlled to move along the center of the pipe (10) inside the pipe (10).

[0113] At this time, it is desirable for the robot (10) for pipe inspection to move in a straight line along the center of the pipe (10) through the feedback loop of the real-time feedback adjustment step (S35) while inspecting the inside of the pipe (10).

[0114] Referring to (A) of FIG. 7, the robot (10) for pipe inspection may not be able to move in a straight line along the center of the pipe (10) inside the pipe (10) because the direction of movement is not accurately set before the process of the high-speed inspection method (S30) for the robot for pipe inspection is performed.

[0115] Referring to (B) of FIG. 7, the robot (10) for pipe inspection can inspect the inside of the pipe (10) by moving in a straight line along the center of the pipe (10) as the process of the high-speed inspection method (S30) for pipe inspection progresses.

[0116] Control devices and devices constituting the control devices

[0117] Below, the structure of the control device (115) provided in the pipe inspection robot (10) of the present invention will be described in detail.

[0118] FIG. 8 is a block diagram illustrating a control device and a device constituting the control device according to one embodiment of the present invention.

[0119] In one embodiment, a control device (115) is provided in the main body (110) and can estimate the position of the pipe inspection robot (100) inside the pipe (10) and control the position and movement direction of the pipe inspection robot (100).

[0120] Such a control device (115) may be equipped with a first encoder (115a), a second encoder (115b), a data combining unit (115c), a data calculating unit (115d), and a position estimation unit (115e), as shown in FIG. 8.

[0121] In one embodiment, the first encoder (115a) may be attached to a cable reel (not shown) for driving the front wheel (130) and the rear wheel (140).

[0122] At this time, a cable reel (not shown) is provided on each of the front wheel (130) and rear wheel (140), and refers to a device that winds or unwinds a connected cable according to the movement of the robot (100) for pipe inspection.

[0123] In addition, the first encoder (115a) may be a reel counter that converts the rotational motion of the cable reel into a digital signal and estimates the current position of the pipe inspection robot (100) inside the pipe (10) based on the number of rotations of the cable reel.

[0124] More specifically, the first encoder (115a) calculates the number of rotations of the cable reel when the pipe inspection robot (100) moves forward in one direction (forward) inside the pipe (10), calculates the travel distance by which the cable is unwound based on the number of rotations of the cable reel, calculates the travel distance of the pipe inspection robot (100) based on the travel distance by which the cable is unwound, and accumulates the calculated travel distance based on the position of the pipe inspection robot (100) when calculating the number of rotations of the reel, thereby estimating the current position of the pipe inspection robot (100).

[0125] That is, it is preferable that the first encoder (115a) operates only when the pipe inspection robot (100) moves forward in one direction to calculate the rotational speed of the cable reels provided in the front wheel (130) and the rear wheel (140), respectively.

[0126] In one embodiment, the second encoder (115b) may be a device that is attached to a cable reel (not shown) like the first encoder (115a) and converts the rotational motion of the cable reel into a digital signal, but unlike the first encoder (115a), it may be a wheel counter that estimates the current position of the pipe inspection robot (100) inside the pipe (10) based on the rotational speed of the front wheel (130) and the rear wheel (140).

[0127] More specifically, the second encoder (115b) calculates the number of rotations of the cable reel when the pipe inspection robot (100) moves backward in the other direction (rearward) inside the pipe (10), calculates the number of rotations of the front wheel (130) and the rear wheel (140) based on the number of rotations of the cable reel, calculates the movement distance of the pipe inspection robot (10) based on the number of rotations of the front wheel (130) and the rear wheel (140), and accumulates the movement distance calculated based on the position of the pipe inspection robot (100) when calculating the number of rotations of the front wheel (130) and the rear wheel (140), thereby estimating the current position of the pipe inspection robot (100).

[0128] That is, it is desirable that the second encoder (115b) operate only when the pipe inspection robot (100) moves backward in the other direction to calculate the rotational speed of the front wheel (130) and the rear wheel (140).

[0129] In one embodiment, the data combining unit (115c) can primarily determine the current position of the pipe inspection robot (100) by combining the current position information of the pipe inspection robot (100) estimated from the first encoder (115a) and the current position information of the pipe inspection robot (100) estimated from the second encoder (115b).

[0130] Additionally, the data combining unit (115c) can transmit the current location information of the primarily determined pipe inspection robot (100) to the location estimation unit (115e).

[0131] In one embodiment, the data calculation unit (115d) may receive a front measurement image (1210) influenced by light provided by an LED light (126) from a multi-camera module (121).

[0132] In addition, the data calculation unit (115d) can calculate the movement distance of the pipe inspection robot (100) by analyzing the frame of the front measurement image (1210) based on the visual odometry technique for tracking the movement of the pipe inspection robot (100).

[0133] At this time, the data calculation unit (115d) can extract feature points from the frame of the front measurement image (1210) based on an image processing algorithm, and the image processing algorithm can be at least one of SIFT (Scale-Invariant Feature Transform), SURF (Speeded-Up Robust Features), and ORB (Oriented FAST and Rotated BRIEF).

[0134] And the data calculation unit (115d) can calculate the movement direction and distance of the pipe inspection robot (100) by matching feature points between frames of continuous front measurement images (1210) to track the movement of the pipe inspection robot (100), and then transmit the movement direction and distance information of the pipe inspection robot (100) to the position estimation unit (115e).

[0135] However, since the visual odometry technique is sensitive to changes in lighting, its accuracy may decrease in a dark environment such as the inside of a pipe (10). Accordingly, the data calculation unit (115d) may calculate the accuracy of the movement direction and distance information of the pipe inspection robot (100) and then transmit the movement direction and distance information of the pipe inspection robot (100) to the position estimation unit (115e).

[0136] At this time, if the data calculation unit (115d) calculates the accuracy of the movement direction and distance information of the pipe inspection robot (100) based on whether the feature points are accurately matched due to the influence of the light provided by the LED light (126), and when the percentile (%) of the accuracy of the movement direction and distance information of the pipe inspection robot (100) is equal to or higher than a preset percentile, the calculated movement direction and distance information of the pipe inspection robot (100) can be transmitted to the position estimation unit (115e).

[0137] In contrast, if the percentile of accuracy of the movement direction and distance information of the pipe inspection robot (100) is less than a preset percentile, the data calculation unit (115d) may not transmit the calculated movement direction and distance information of the pipe inspection robot (100) to the position estimation unit (115e).

[0138] In one embodiment, the position estimation unit (115e) can finally estimate the current position of the pipe inspection robot (100) based on the current position information of the pipe inspection robot (100) transmitted from the data combination unit (115c) and the movement direction and distance information of the pipe inspection robot (100) transmitted from the data calculation unit (115d).

[0139] However, if the position estimation unit (115e) does not receive information on the movement direction and distance of the pipe inspection robot (100) from the data calculation unit (115d), the current position of the pipe inspection robot (100) can be finally estimated using the current position information of the pipe inspection robot (100) received from the data combination unit (115c).

[0140] Front and rear wheel structure

[0141] Hereinafter, the structures of the front wheel (130) and the rear wheel (140) provided in the pipe inspection robot (10) of the present invention will be described in detail based on the front wheel (130).

[0142] FIG. 9 is an exploded perspective view of a front wheel according to one embodiment of the present invention, and FIG. 10 is a block diagram illustrating a driving unit and a device constituting the driving unit according to one embodiment of the present invention.

[0143] Referring to FIG. 9, the front wheel (130) may be equipped with a tire (131), a tire mount bracket (132), a sealing cap (133), a waterproof / heat-dissipating housing (134), a hub (135), and a fixed bracket (136).

[0144] The tire (131) is made of a rubber material to absorb vibration and shock generated while the pipe inspection robot (100) moves inside the pipe (10), and can support the load of the main body (110) and the camera unit (120) connected to the main body (110).

[0145] The tire mount bracket (132) is fitted to the tire (131) and can absorb vibration and shock generated while the pipe inspection robot (100) moves inside the pipe (10) together with the tire (131).

[0146] In one embodiment, the tire mount bracket (132) can house therein a driving unit (1320) for driving the front wheel unit (130).

[0147] Referring to FIG. 10, the driving unit (1320) may be equipped with an in-wheel motor (1321), a reducer (1322), a control unit (1323), and a sensor (1324).

[0148] In one embodiment, the in-wheel motor (1321) is a motor that drives the front wheel (130), and may differ from a conventional motor mounted within the vehicle chassis in that it is positioned inside the tire mount bracket (132).

[0149] In one embodiment, the reducer (1322) can convert the torque of the in-wheel motor (1321) and transmit it to the front wheel (130).

[0150] In one embodiment, the control unit (1323) can implement the driving performance of the robot (100) for pipe inspection by controlling the speed and torque of the in-wheel motor (1321).

[0151] Additionally, the control unit (1323) can independently control the rotation of a pair of front wheels (130) for precise driving of the pipe inspection robot (100).

[0152] In one embodiment, the sensor (1324) can measure the speed, torque, and position of the front wheel (130) to provide feedback to the control unit (1323) for precise control of the front wheel (130) and stable driving of the pipe inspection robot (100).

[0153] This driving unit (1320) may be an in-wheel type modular unit in which the in-wheel motor (1321), reducer (1322), control unit (1323), and sensor (1324) are implemented in the form of a single module and are placed inside the tire mount bracket (132).

[0154] Referring again to FIG. 9, the sealing cap (133) functions as a cover coupled to the tire mount bracket (132) to prevent the in-wheel type modular driving unit (1320) disposed inside the tire mount bracket (132) from being separated from the tire mount bracket (132).

[0155] In one embodiment, a waterproof / heat-proof housing (134) is combined with a sealing cap (133), and while a pipe inspection robot (100) inspects the inside of the pipe (10), water, moisture, etc. inside the pipe (10) can be prevented from infiltrating into the drive unit (1320) disposed inside the tire mount bracket (132) (waterproofing), and at the same time, heat generated in the drive unit (1320) can be released (heat dissipated) to the inside of the pipe (10) outside the tire mount bracket (132).

[0156] In one embodiment, the hub (135) may be provided with a communication / power connector (135a) on one side to enable the driving unit (1320) to receive power from a battery (not shown) built into the main body (110) and to transmit a control signal from the control device (115).

[0157] In one embodiment, the fixed bracket (136) is a member that fixes the tire mount bracket (132) so that it remains in a state of being fitted to the tire (131), and can absorb vibration and shock generated while the pipe inspection robot (100) moves inside the pipe (10) together with the tire (131) and the tire mount bracket (132).

[0158] The detailed description of the preferred embodiments of the present invention disclosed above has been provided to enable those skilled in the art to implement and practice the present invention. While the above description has been made with reference to preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the scope of the present invention. For example, those skilled in the art can utilize the individual components described in the above-described embodiments in combination with each other. Accordingly, the present invention is not intended to be limited to the embodiments described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0159] The present invention may be embodied in other specific forms without departing from the technical spirit and essential characteristics thereof. Therefore, the above detailed description should not be construed as limiting in all respects but should be considered as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all changes coming within the equivalent scope of the present invention are intended to be included therein. The present invention is not intended to be limited to the embodiments set forth herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Furthermore, claims that are not explicitly cited in the claims may be combined to form an embodiment or incorporated into a new claim by post-application amendment.

[0160] Description of the symbol

[0161] 10: Piping, 100: Robot for pipe inspection,

[0162] 110: main body, 111: front wheel steering unit,

[0163] 112: Rear wheel steering, 113: Rollover prevention module,

[0164] 115: Control device, 115a: Cable reel,

[0165] 115b: 1st encoder, 115c: 2nd encoder,

[0166] 115d: Data combining unit, 115d: Data calculation unit,

[0167] 115e: Position estimation unit, 120: Camera unit,

[0168] 121: Multi-camera module, 121a~121b: 1st~4th RGB cameras,

[0169] 122: PTZ camera, 123: Angle adjustment hinge,

[0170] 124: Camera housing, 125: Lens section,

[0171] 125a~125d: 1st~4th lenses, 126: LED lighting,

[0172] 127: Cover, 130: Front wheel,

[0173] 131: Tire, 132: Tire mount bracket,

[0174] 133: Sealing cap, 134: Waterproof / heat-resistant housing,

[0175] 135: Hub, 135a: Communication / Power Connector,

[0176] 136: Fixed bracket, 140: Rear wheel,

[0177] 1151: Imaginary straight line, 1152: Imaginary center,

[0178] 1210: Front measurement image, 1220: Precision measurement image,

[0179] 1320: Drive unit, 1321: In-wheel motor,

[0180] 1322: Reducer, 1323: Control unit,

[0181] 1324: Sensor.

Claims

1. In a pipe inspection robot for checking the internal condition of pipes, The above pipe inspection robot is, A main body having a battery, a position estimation device for the robot for inspecting the pipe, and a control device for controlling the position and movement direction of the robot for inspecting the pipe; A camera unit in which heterogeneous cameras are combined to capture the interior of the above pipe; and A robot for pipe inspection, characterized in that it includes a front wheel and a rear wheel, which are a pair of wheels capable of independent rotational driving on the left and right sides of the front and rear ends of the main body.

2. In paragraph 1, The above camera part, A multi-camera module comprising a plurality of RGB cameras that capture a front measurement image by photographing the inside of the above pipe; An angle adjustment hinge for adjusting the angle of the plurality of RGB cameras; A camera housing that houses a multi-camera module coupled with the above angle adjustment hinge, is open on one side and the other side, and has an opening formed on the side; A PTZ camera that is coupled to one side of the camera housing to close one side of the camera housing, enlarges a specific area inside the pipe, and then captures a precise measurement image by taking a picture; A cover part that is coupled to the other side of the camera housing and closes the other side of the camera housing; A lens unit made of a transparent material and consisting of a plurality of lenses for protecting the plurality of RGB cameras by being connected to the above opening; and A robot for pipe inspection, characterized in that it includes an LED light that provides light so that the plurality of RGB cameras can capture the front measurement image.

3. In paragraph 2, The above camera, After continuously collecting front measurement images through the above multi-camera module and precision measurement images through the above PTZ camera, they are transmitted to the above control device. The above control device, By assigning a timestamp to each of the above front measurement image and precision measurement image, they are synchronized temporally and then images of the same point in time are matched. After detecting the feature points of the front measurement image and the precision measurement image based on the feature point detection algorithm, the relationship between the front measurement image and the precision measurement image is estimated by matching the feature points. After calculating a transformation matrix between the front measurement image and the precision measurement image based on the above feature point matching, a geometric transformation is calculated so that the precision measurement image is aligned with the front measurement image. After superimposing the above-mentioned aligned precision measurement image on the front measurement image, the front measurement image and the precision measurement image are synthesized by converting based on a blending technique, A robot for pipe inspection characterized in that it continuously updates and synthesizes the above-mentioned front measurement image and precision measurement image to create a composite image.

4. In paragraph 3, The above control device, After removing noise from the above composite image, the boundary of the pipe is emphasized through edge detection, By converting the points of the composite image with the boundary of the pipe emphasized through noise removal and edge detection into a parameter space, multiple straight lines are detected, and then the boundary line of the pipe is detected using the straight lines. The center point of the detected straight line is calculated to detect the center inside the pipe, and then the center coordinates are determined according to the center. After calculating the error between the current position of the pipe inspection robot and the center coordinates of the pipe, the position and movement direction of the pipe inspection robot and the shooting angle of the camera are adjusted according to the calculated error. A pipe inspection robot characterized in that the position and movement direction of the pipe inspection robot and the shooting angle of the camera are continuously adjusted based on composite images collected in real time from the camera, and the pipe inspection robot is controlled to move along the center of the pipe inside the pipe through repetitive feedback.

5. In paragraph 2, The above camera, The above plurality of RGB cameras continuously photograph the inside of the pipe while the pipe inspection robot moves in one direction inside the pipe, and then acquires an image of a portion of the pipe and transmits it to the control device. The above control device, A robot for pipe inspection characterized in that it corrects the distortion of a portion of the pipe image, converts the distorted portion of the pipe image into a plane, and then connects the portion of the pipe image converted into a plane to create a single internal image of the pipe.

6. In paragraph 5, The above control device, A pipe inspection robot characterized in that, when the pipe inspection robot enters the interior of the pipe and an internal image of the pipe is generated for the first time, the pipe inspection robot is controlled to move in the one direction while generating the internal image of the pipe.

7. In paragraph 5, The above control device, A robot for pipe inspection characterized in that, when the number of pipe internal images generated to date is two or more, a matching algorithm is used to calculate a matching point between each pipe internal image based on an overlapping area of ​​each pipe internal image generated to date, and the multiple pipe internal images are connected based on the matching point to synthesize a single continuous front measurement image.

8. In paragraph 2, The above control device, A first encoder, which is a reel counter that estimates the current position of the pipe inspection robot based on the rotational speed of the cable reels provided on the front and rear wheel sections, respectively; A second encoder, which is a wheel counter that estimates the current position of the pipe inspection robot based on the rotational speed of the front and rear wheels; A data combining unit that primarily determines the current position of the pipe inspection robot by combining the current position information of the pipe inspection robot estimated from the first encoder and the current position information of the pipe inspection robot estimated from the second encoder; A data calculation unit that calculates the movement distance of a pipe inspection robot by analyzing frames of front measurement images transmitted from the multi-camera module based on a visual odometer technique, and tracks the movement of the pipe inspection robot by matching feature points between frames of continuous front measurement images to calculate the movement direction and distance of the pipe inspection robot; and A pipe inspection robot, characterized in that it includes a position estimation unit that finally estimates the current position of the pipe inspection robot based on the current position information of the pipe inspection robot transmitted from the data combination unit and the movement direction and distance information of the pipe inspection robot transmitted from the data calculation unit.

9. In paragraph 1, The above front wheel part and the above rear wheel part, tire; A tire mount bracket that is fitted to the tire and houses a driving unit for driving the front and rear wheels inside; A sealing cap coupled to the tire mount bracket to prevent the driving unit from being separated from the tire mount bracket; A waterproof / heat-dissipating housing combined with the sealing cap to prevent water and moisture from entering the inside of the pipe into the driving unit and at the same time to release heat generated from the driving unit to the outside of the tire mount bracket; A hub having a communication / power connector provided on one side so that the driving unit receives power from the battery and transmits a control signal from the control device; and A robot for pipe inspection, characterized in that it includes a fixing bracket for fixing the tire mount bracket so that it is maintained in a state of being fitted to the tire.

10. In paragraph 9, The above driving part, A robot for pipe inspection, characterized in that it is an in-wheel type modular type accommodated on the inside of the above tire mount bracket.

Images