KR102377070B1 - Pose and Distance Control Method of CCS Inspection Robot - Google Patents

Abstract

The present invention relates to a method of maintaining the posture and distance of an inspection robot (20) mounted and flying with a camera (25): the inspection robot (20) uses a laser irradiator (23) to display a standard on the surface of an object. The shape and the actual shape are input to the camera 25, and the inspection robot 20 is rotated up and down, left and right, and moves forward and backward according to a set algorithm by comparing the images of the reference shape and the actual shape.
Accordingly, in the process of inspecting the cargo hold, the flying robot has the effect of maintaining the posture and distance required to perform a set task through calculations based on a laser of a specific shape.

Description

How to maintain the posture and distance of a cargo hold inspection robot {Pose and Distance Control Method of CCS Inspection Robot}

The present invention relates to a cargo hold inspection robot, and more specifically, to a method of maintaining the posture and distance of a cargo hold inspection robot that allows easy inspection of large cargo holds installed in LNGCs, etc.

The demand for gas carriers and FLNG is increasing due to shale gas development. The core of LNGC and FLNG lies in the insulation system (CCS) that stores the gas, and regular inspection and maintenance are that important. However, the conventional method of installing scaffolding in a CCS and having a person visually check it is not practical because it is very costly and time-consuming. Accordingly, efforts are being made to use flying robots equipped with cameras.

In relation to this, known prior art documents that can be referred to include Korea Registered Utility Model Publication No. 0452737 (Prior Document 1), Korean Patent Publication No. 0537780 (Prior Document 2), etc.

Prior document 1 has upper and lower vertical wings and left and right horizontal wings at the rear of the air bag filled with helium, a wireless camera is installed at the front and lower part of the air bag, and a propeller that changes direction through a hole formed on the surface of one vertical wing, A rear motor that drives the propeller is installed. Accordingly, the effect of filming with an airship with stability and turning ability is expected.

Prior document 2 is a photography robot equipped with a digital camera capable of changing the direction of the lens and capable of levitating; and a levitation control device for remotely controlling the levitation of the photography robot, a lens control device for controlling the direction and zoom of the camera lens, a viewfinder for the camera, and a remote control equipped with a shutter button for the camera. . Accordingly, it is expected to be used for industrial purposes, such as remotely taking pictures of dangerous places.

In order to easily operate the LNGC cargo hold inspection robot, the inspection robot must look vertically at the cargo hold surface and move while maintaining a certain distance. However, because the cargo hold and the inspection robot are mechanically separated, there is no information to know the attitude and distance of the inspection robot with respect to the cargo hold. Not only do prior documents 1 and 2 lack structural suitability for application to cargo holds, but even if the wireless camera and wireless transceiver of prior document 1 are used or the motion data and image data of prior document 2 are partially used, there are limits to the performance of inspection tasks. see.

1. Korean Registered Utility Model Publication No. 0452737 “Radio-controlled unmanned airship” (Publication date: 2010.04.27.) 2. Korean Patent Publication No. 0537780 “Digital flight filming device” (Publication date: 2005.07.12.)

The purpose of the present invention to improve the above-described conventional problems is to effectively maintain the attitude of the cargo hold flying robot perpendicular to the cargo hold surface by using a laser of a specific shape and at the same time maintain a certain distance from the cargo hold inspection robot. The goal is to provide a way to maintain distance.

In order to achieve the above object, the present invention relates to a method of maintaining the posture and distance of an inspection robot that flies with a camera mounted on it: the inspection robot uses a laser irradiator to determine the reference shape and the actual shape displayed on the surface of the object. It is characterized in that the inspection robot is inputted using a camera, and the inspection robot is rotated up and down, left and right, and moves back and forth according to a set algorithm by comparing the image of the reference shape and the actual shape.

As a detailed configuration of the present invention, the reference figure and the actual figure are characterized in that they are examined in a shape selected from square, triangle, circle, and oval.

As a detailed configuration of the present invention, the vertical rotation algorithm determines the rotation speed by comparing distance data from the image center of the reference figure to the upper and lower sides, and distance data from the image center of the actual figure to the upper and lower sides, respectively. It is characterized by

As a detailed configuration of the present invention, the left and right rotation algorithm determines the rotation speed by comparing distance data from the image center of the reference shape to the left and right sides, respectively, and distance data from the image center of the actual shape to the left and right sides, respectively. It is characterized by

As a detailed configuration of the present invention, the forward and backward movement algorithm is characterized in that the movement speed is determined by comparing the area of the reference shape and the area of the actual shape.

As described above, according to the present invention, during the process of inspecting a cargo hold, a flying robot has the effect of maintaining the posture and distance required to perform a set task through calculations based on a laser of a specific shape.

1 is a configuration diagram showing an example of application of the method according to the present invention.
Figure 2 is a block diagram showing the main circuit connection state of Figure 1
Figure 3 is a schematic diagram illustrating a reference shape and an actual shape according to the present invention.
Figure 4 is a flow chart showing the main steps of the method according to the invention

Hereinafter, embodiments of the present invention will be described in detail based on the attached drawings.

The present invention proposes a method for maintaining the posture and distance of an inspection robot (20) flying with a camera (25) mounted on it. Figure 1 illustrates a state of inspecting a large cargo hold 10 installed in an LNGC, etc. using a flight-capable inspection robot 20, but is not necessarily limited thereto. The inspection robot 20 is equipped with a propellant 22, such as an omnidirectional thruster, on the lower side of a buoyant body 21, such as a helium balloon. A laser irradiator 23, a camera 25, and a control module 26 are mounted on the inspection robot 20.

In addition, it is recommended to use a separate control unit 30 to miniaturize the inspection robot 20. The control unit 30 is equipped with a calculation unit 32, an input/output unit 34, and a communication unit 36, and can process information communication with an externally installed repeater 38. The calculation unit 32 is based on a microprocessor and memory, and the input/output unit 34 is based on an interface circuit for input/output signals. The communication unit 36 communicates information with the control module 26 of the inspection robot 20 through wireless communication.

According to the present invention, the inspection robot 20 uses the laser irradiator 23 to input the reference shape and actual shape displayed on the surface of the object into the camera 25. The object refers to an expensive insulation material installed on the inner wall of the cargo hold 10, but is not limited thereto. The reference figure is an image created by manually manipulating the inspection robot 20 to obtain an image at an appropriate distance from the object. In Figure 3, the image center (CR) of the reference shape can be calculated using a camera calibration method. Accordingly, the distance from the image center (CR) to the top point, the distance to the bottom point, the distance to the left point, and the distance to the right side point are obtained. The actual shape is an image created by acquiring it at a sampling cycle set during the automatic flight process of the inspection robot 20. The image center (CA) of the actual figure shown in FIG. 3 is obtained on the same principle as the image center (CR) of the reference figure, and the distances from the image center (CA) to the top, bottom, left, and right points are also the same. Saved.

As a detailed configuration of the present invention, the reference figure and the actual figure are characterized in that they are examined in a shape selected from square, triangle, circle, and oval. In Figure 3, the reference shape and the actual shape are illustrated as squares, but they are not limited to this and other shapes may be selected depending on the shape of the object. Of course, this is determined in hardware terms according to the specifications of the laser irradiator 23.

In addition, according to the present invention, the inspection robot 20 is rotated up and down, left and right, and moves back and forth according to a set algorithm by comparing the images of the reference shape and the actual shape. By adjusting each propellant 22 radially disposed on the inspection robot 20, the vertical tilt posture, left and right tilt posture, and front and rear distance can be changed. The algorithm for changing the posture and distance of the inspection robot 20 is calculated based on distance data from the above-described image center (CR) (CA) to the upper, lower, left, and right side points, respectively.

As a detailed configuration of the present invention, the vertical rotation algorithm determines the rotation speed by comparing distance data from the image center of the reference figure to the upper and lower sides, and distance data from the image center of the actual figure to the upper and lower sides, respectively. It is characterized by The speed for vertical rotation of the inspection robot 20 can be determined using the following [Equation 1]. Here, k1 is a proportional control gain for vertical rotation and can be set appropriately depending on the system.

[Formula 1]

Up and down rotation speed = k1*(Distance from CR to upper side / Distance from CR to lower side - Distance from CA to upper side / Distance from CA to lower side)

If the comparison value of [Formula 1] is negative, the inspection robot (20) is facing above the standard posture and must be rotated downward. Conversely, if the comparison value is positive, the inspection robot (20) is facing below the reference posture. Therefore, it must be rotated upward. In other words, a positive (+) vertical rotation speed means rotating upward, and a negative (-) vertical rotation speed means rotating downward.

Meanwhile, Figure 3 illustrates the image comparison state in the algorithm for vertical rotation of the inspection robot 10.

As a detailed configuration of the present invention, the left and right rotation algorithm determines the rotation speed by comparing distance data from the image center of the reference shape to the left and right sides, respectively, and distance data from the image center of the actual shape to the left and right sides, respectively. It is characterized by The speed for vertical rotation of the inspection robot 20 can be determined using the following [Equation 2]. Here, k2 is the proportional control gain for left and right rotation and can be set appropriately depending on the system.

[Formula 2]

Left and right rotation speed = k2*(distance from CR to left side / distance from CR to right side - distance from CA to left side / distance from CA to right side)

If the comparison value of [Formula 2] is negative, the inspection robot 20 is facing to the left compared to the standard posture, so it must be rotated to the right. Conversely, if the comparison value is positive, the inspection robot 20 is facing to the right compared to the standard posture. Therefore, it must be rotated to the left. In other words, a positive (+) left/right rotation speed means rotating to the left, and a negative (-) left/right rotation speed means rotating to the right.

As a detailed configuration of the present invention, the forward and backward movement algorithm is characterized in that the movement speed is determined by comparing the area of the reference shape and the area of the actual shape. The speed for forward and backward movement of the inspection robot 20 can be determined using the following [Equation 3]. Here, k3 is the proportional control gain for maintaining a constant distance and can be set appropriately depending on the system.

[Formula 3]

Forward and backward movement speed = k3*(reference square area - actual square area)

If the comparison value of [Formula 3] is negative, the inspection robot (10) is closer than the standard distance and must be moved backward. Conversely, if the comparison value is positive, the inspection robot (10) is farther than the standard distance and must be moved forward. You have to do it. In other words, a positive (+) forward and backward movement speed means moving forward, and a negative (-) forward and backward movement speed means moving backward.

The present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Therefore, it should be said that such variations or modifications fall within the scope of the patent claims of the present invention.

10: cargo hold 20: inspection robot
21: buoyancy body 22: propellant
24: Laser irradiator 25: Camera
26: Control module 30: Control unit
32: calculation unit 34: input/output unit
36: Communication Department 38: Repeater

Claims (5)

In the method of maintaining the posture and distance of the inspection robot 20 flying with the camera 25:
The inspection robot 20 uses the laser irradiator 23 to input the reference shape and actual shape displayed on the surface of the object into the camera 25,
The inspection robot 20 is rotated up and down, left and right, and moves forward and backward according to an algorithm set by comparing the image of the reference shape and the actual shape,
The vertical rotation algorithm determines the rotation speed of the cargo hold inspection robot by comparing distance data from the image center of the reference shape to the upper and lower sides, respectively, and distance data from the image center of the actual shape to the upper and lower sides, respectively. How to maintain posture and distance. In claim 1,
A method of maintaining the posture and distance of a cargo hold inspection robot, characterized in that the reference shape and the actual shape are examined in a shape selected from square, triangle, circle, and oval. delete In claim 1,
The left and right rotation algorithm determines the rotation speed of the cargo hold inspection robot by comparing distance data from the image center of the reference shape to the left and right sides, respectively, and distance data from the image center of the actual shape to the left and right sides, respectively. How to maintain posture and distance. In claim 1,
The forward and backward movement algorithm is a method of maintaining the posture and distance of a cargo hold inspection robot, characterized in that the movement speed is determined by comparing the area of the reference shape and the area of the actual shape.

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