CN111354036A - Underwater optical positioning algorithm applied to pressure container - Google Patents

Underwater optical positioning algorithm applied to pressure container Download PDF

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CN111354036A
CN111354036A CN201811565142.7A CN201811565142A CN111354036A CN 111354036 A CN111354036 A CN 111354036A CN 201811565142 A CN201811565142 A CN 201811565142A CN 111354036 A CN111354036 A CN 111354036A
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rov
camera
angle
pressure vessel
algorithm applied
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CN111354036B (en
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陈姝
魏文斌
张志义
冯美名
张益成
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Research Institute of Nuclear Power Operation
China Nuclear Power Operation Technology Corp Ltd
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Research Institute of Nuclear Power Operation
China Nuclear Power Operation Technology Corp Ltd
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/70—Determining position or orientation of objects or cameras
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C11/00—Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C17/00—Monitoring; Testing ; Maintaining
    • G21C17/003—Remote inspection of vessels, e.g. pressure vessels
    • G21C17/01—Inspection of the inner surfaces of vessels
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C17/00—Monitoring; Testing ; Maintaining
    • G21C17/003—Remote inspection of vessels, e.g. pressure vessels
    • G21C17/013—Inspection vehicles
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10004—Still image; Photographic image
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Abstract

The invention belongs to an underwater positioning technology, and particularly relates to an underwater optical positioning algorithm applied to a pressure container environment. Under existing inspection conditions, positioning of the underwater ROV must first be achieved to make it possible to guide the ROV to a specified location. The method comprises the following steps: step 1, inputting the length a and radius data r of a pressure vessel bus, a vertical field angle A of a camera and the height B of a CCD target surface of the camera; step 2, solving a critical angle; step 3, calculating an angle theta corresponding to the unit radial length of the image plane of the camera0Step 4, turning on an LED lamp on the ROV, and step 5, adjusting the pitch angle α of the camera arranged in the center of the remote control platform according to the principle from large to small until a bright spot enters the central line of the field of view of the cameraThe rotation angle at this time is the azimuth angle of the ROV; step 6 record the bright spot position (0, y)0) And calculating the central variable. Step 7 calculates the depth x of the ROV. By using the method, the position of the ROV can be obtained by using the LED lamp on the ROV under the assistance of the camera.

Description

Underwater optical positioning algorithm applied to pressure container
Technical Field
The invention belongs to an underwater positioning technology, and particularly relates to an underwater optical positioning algorithm applied to a pressure container environment.
Background
Nuclear reactor pressure vessels are typically constructed of an upper cylinder with water inlets and outlets on the sides of the cylinder and a lower hemisphere. FIG. 1 is a schematic cross-sectional view of a nuclear reactor pressure vessel. The pressure vessel has welding seams at the junction of the water outlet, the water inlet, the cylinder body and the bottom hemisphere and at some other specific positions. If these welds are damaged, there is a greater risk of continued use at high temperatures and pressures. Therefore, periodic inspection and repair of the pressure vessel is required. Usually, an underwater remote control underwater vehicle (ROV) has to carry out ultrasonic detection on a welding seam at a specified position to check whether a damage defect exists. For this purpose, the positioning of the underwater ROV must first be achieved, in order to be able to guide the ROV to a given location.
In order to realize the positioning of the ROV, a camera is arranged on a central beam remote control platform above the pressure container, the underwater vehicle ROV is arranged in the pressure container, and an LED lamp is arranged on the ROV. The camera on the remote platform has azimuth rotation and pitch adjustment functions, see fig. 2.
The position of the ROV can be obtained by using an LED lamp on the ROV with the assistance of a camera.
Disclosure of Invention
The invention aims to provide an underwater ROV optical positioning algorithm applied to a pressure vessel environment, which can establish a mathematical model by utilizing the size parameters of the pressure vessel, the installation position of a camera and the parameters of LED lamp light on an ROV on a CCD target surface of the camera to obtain the accurate position of an ROV of a submersible vehicle.
The technical scheme of the invention is as follows:
an underwater ROV optical positioning algorithm applied to a pressure vessel environment, comprising the following steps:
step 1, inputting the length a (m) of a pressure container bus and radius data r (m), the vertical field angle A (rad) (or horizontal field angle) of a camera and the height B (mm) (or width) of a CCD target surface of the camera;
step 2) solving the critical angle
Figure BDA0001914339290000021
Step 3) calculating the angle theta corresponding to the unit radial length of the image plane of the camera0(rad)
Figure BDA0001914339290000022
Step 4), turning on an LED lamp on the ROV;
step 5) adjusting the pitch angle α rad of the camera arranged in the center of the remote control platform according to the principle from large to small, wherein the times are not more than
Figure BDA0001914339290000023
Which comprises
Figure BDA0001914339290000024
(not adjusted) and
Figure BDA0001914339290000025
rotating until the bright spot enters the central line of the camera view field, wherein the rotating angle is the azimuth angle of the ROV;
step 6) recording the position (0, y) of the bright spot0) To find the central variable
Figure BDA0001914339290000026
Step 7) the depth x (m) of the ROV is calculated by using the following algorithm:
Figure BDA0001914339290000027
the invention has the following remarkable effects: according to the underwater ROV optical positioning algorithm for the pressure container environment, the position of the submersible vehicle ROV can be accurately obtained by utilizing the size parameter of the pressure container, the installation position parameter of the camera and the LED bright light on the ROV, and the method is scientific, full-coverage in detection and strong in calculation real-time.
Drawings
FIG. 1 is a schematic cross-sectional view of a nuclear reactor pressure vessel
FIG. 2 schematic diagram of sectional view camera shooting and ROV measurement of a certain nuclear reactor pressure vessel
FIG. 3 is a graph of variable θ as a function of depth x
FIG. 4 is a schematic view of sectional view of a nuclear reactor pressure vessel, showing the camera shooting and ROV measuring angles
Detailed Description
The following detailed description of the patent refers to the accompanying drawings and specific embodiments:
the invention is described in further detail below with reference to the figures and the embodiments.
An underwater ROV optical positioning algorithm applied to a pressure vessel environment, comprising the following steps:
for a pressure vessel shaped as in fig. 2, the relationship between the variable θ and the depth x is established using knowledge about the analytical geometry, see fig. 3.
And establishing a rectangular coordinate system Oxy by taking O as a coordinate origin, OC as an x axis and OA as a y axis, wherein the coordinates of O (0,0), O (a,0), A (0, r), B (a, r) and C (a + r,0) and the coordinates of the points are as follows, and if the abscissa of the point D between the points AB is x and ∠ COD is theta, the point D is as follows
Figure BDA0001914339290000031
If the abscissa of the point E on the arc BC is x, the ordinate is y, and ∠ COE is θ, then:
Figure BDA0001914339290000032
and (x-a)2+y2＝r2. Obtaining a result according to the characteristic that the E point is positioned at the upper right
Figure BDA0001914339290000041
At the point of the boundary B,
Figure BDA0001914339290000042
the above discussion illustrates the basic principle of solving for the depth x of an ROV.
Step 1, inputting the length a (m) of a pressure container bus and radius data r (m), the vertical field angle A (rad) (or horizontal field angle) of a camera and the height B (mm) (or width) of a CCD target surface of the camera; the data can be obtained through parameter introduction on a product specification;
step 2) solving the critical angle of the depth formula according to the length and radius data of the pressure vessel bus
Figure BDA0001914339290000043
Step 3) calculating the angle corresponding to the unit radial length of the CCD target surface of the camera by using the view field of the camera and the size of the CCD target surface
Figure BDA0001914339290000044
Step 4), turning on an LED lamp on the ROV for the camera to search ROV target information;
step 5) adjusting the pitch angle α rad of the camera arranged in the center of the remote control platform according to the principle from large to small, wherein the times are not more than
Figure BDA0001914339290000045
Which comprises
Figure BDA0001914339290000046
(not adjusted) and
Figure BDA0001914339290000047
rotating until the bright spot enters the central line of the camera view field, wherein the rotating angle is the azimuth angle of the ROV;
step 6) recording the position (0, y) of the bright spot0) To find outVariables of
Figure BDA0001914339290000048
y0The positive and negative of (a) reflect the up-and-down position relation between the position D of the ROV and the intersection point Ox of the normal line of the mirror surface of the camera and the curved surface of the container, as shown in FIG. 4;
step 7), the depth x (m) of the ROV is calculated by using a plane analytic geometry method:
Figure BDA0001914339290000051
in the above steps, step 1) is to obtain the known parameters required by the algorithm: the length and radius of the pressure vessel generatrix, the camera field angle parameter, and the camera image plane size. And 2) solving a critical angle by using the length and the radius of the pressure vessel bus. Step 3) calculating an angle theta corresponding to the unit radial length of the CCD target surface of the camera according to the field angle and the size of the image plane of the camera0(rad), for example, a camera field of view of 60 ° × 45 °, a camera CCD target surface of 6mm × 4.5.5 mm, a length of 1mm corresponding to a 10 ° field of view, steps 4) and 5) are operations performed to measure the orientation and depth of the ROV, from which the orientation of the ROV is obtained simultaneously, steps 6) and 7) are key algorithms to solve for the depth of the ROV.

Claims (7)

1. An underwater optical positioning algorithm applied to a pressure vessel environment, characterized in that: the method comprises the following steps:
step 1, inputting the length a and radius data r of a pressure vessel bus, a vertical field angle A of a camera and the height B of a CCD target surface of the camera;
step 2, solving a critical angle;
step 3, calculating an angle theta corresponding to the unit radial length of the image plane of the camera0；
Step 4, turning on an LED lamp on the ROV;
step 5, adjusting a pitch angle α of the camera arranged in the center of the remote control platform according to a principle from large to small until a bright spot enters the central line of the field of view of the camera, wherein the rotating angle at the moment is the azimuth angle of the ROV;
step 6 record the bright spot position (0, y)0) Calculating a central variable;
step 7 calculates the depth x of the ROV.
2. An underwater optical locating algorithm applied to a pressure vessel environment as claimed in claim 1 wherein: the step 2: the specific way to solve the critical angle is as follows:
Figure FDA0001914339280000011
3. an underwater optical locating algorithm applied to a pressure vessel environment as claimed in claim 1 wherein: the step 3: calculating the angle theta corresponding to the unit radial length of the image plane of the camera0The specific mode is as follows:
Figure FDA0001914339280000012
4. an underwater optical locating algorithm applied to a pressure vessel environment as claimed in claim 3 wherein the step 5 of adjusting the pitch angle α is performed no more than once
Figure FDA0001914339280000013
5. An underwater optical locating algorithm applied to a pressure vessel environment as claimed in claim 4 wherein step 5 is adjusting the pitch angle α wherein
Figure FDA0001914339280000021
(i ═ T-1, T-2, …, 1); when in use
Figure FDA0001914339280000022
It is not adjusted.
6. An underwater optical locating algorithm applied to a pressure vessel environment as claimed in claim 1 wherein: and 6: the specific way to find the central variable is
Figure FDA0001914339280000023
7. An underwater optical locating algorithm applied to a pressure vessel environment as claimed in claim 1 wherein: in step 7, the calculation method for calculating the depth x of the ROV is
Figure FDA0001914339280000024
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104464849A (en) * 2013-09-23 2015-03-25 核动力运行研究所 Device for checking reactor pressure vessel of nuclear power station
CN105190234A (en) * 2012-12-14 2015-12-23 Bp北美公司 Apparatus and method for three dimensional surface measurement
CN107314768A (en) * 2017-07-06 2017-11-03 上海海洋大学 Underwater terrain matching aided inertial navigation localization method and its alignment system
NO20161239A1 (en) * 2016-07-28 2018-01-29 4Subsea As Method for detecting position and orientation of a subsea structure using an ROV
WO2018186750A1 (en) * 2017-04-05 2018-10-11 Blueye Robotics As Camera assisted control system for an underwater vehicle

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105190234A (en) * 2012-12-14 2015-12-23 Bp北美公司 Apparatus and method for three dimensional surface measurement
CN104464849A (en) * 2013-09-23 2015-03-25 核动力运行研究所 Device for checking reactor pressure vessel of nuclear power station
NO20161239A1 (en) * 2016-07-28 2018-01-29 4Subsea As Method for detecting position and orientation of a subsea structure using an ROV
WO2018186750A1 (en) * 2017-04-05 2018-10-11 Blueye Robotics As Camera assisted control system for an underwater vehicle
CN107314768A (en) * 2017-07-06 2017-11-03 上海海洋大学 Underwater terrain matching aided inertial navigation localization method and its alignment system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
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