Circle center positioning method in ultrasonic detection of shoal buried pipeline

A technology of circle center positioning and ultrasonic detection, which is applied in the field of ultrasonic detection of buried pipelines in shoals, can solve the problems of water seepage in cofferdams, unable to accurately determine the position information of pipeline edges, and must be rebuilt, etc., and achieve the effect of accurate positioning.

Active Publication Date: 2018-10-09
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (2) If the location of the cofferdam construction deviates from the leakage site, it must be rebuilt;
[0005] (3) There are safety risks of collapse and water seepage in traditional cofferdams
[0009] The above methods can only qualitatively obtain the sonar image and depth orientation of the pipeline, but cannot accurately locate the radial cross-section of the pipeline, and cannot accurately determine the edge position information of the pipeline

Method used

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  • Circle center positioning method in ultrasonic detection of shoal buried pipeline
  • Circle center positioning method in ultrasonic detection of shoal buried pipeline
  • Circle center positioning method in ultrasonic detection of shoal buried pipeline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] A method for locating the center of a circle in ultrasonic detection of buried pipelines in shoals, the method for locating the center of a circle is based on the time of arrival and the least square method, see figure 1 , the center location method includes the following steps:

[0052] 101: Construct a simplified bright spot model of buried pipelines; use MATLAB to design simulation parameters and obtain simulated echo signals;

[0053] 102: Build a simple single-channel ultrasonic transmitting and receiving experimental platform in the laboratory environment;

[0054] 103: Simulate the complex environment of the shoal, and add Gaussian noise with a signal-to-noise ratio of a certain threshold to the original experimental echo signal to obtain the echo signal;

[0055] 104: Estimate the echo TOA of the echo signal by using the maximum amplitude method, the characteristic parameter correlation detection method, and the fast energy center convergence method, and select...

Embodiment 2

[0076] Combined with the specific calculation formula, Figure 1-Figure 7 , the scheme in embodiment 1 is further introduced, see the following description for details:

[0077] 201: Construct a simplified bright spot model of buried pipelines;

[0078] The detailed operation of this step 201 is:

[0079] 1) if figure 2 As shown, the position of the transducer is taken as the origin O, and the radial cross-section of the pipe is taken as the two-dimensional plane (XOY plane), and a single underwater acoustic transducer and the pipe position coordinate system are constructed. Assuming that the cross-section of the pipe, that is, the circle O', is within the -3dB beam width angle of the transducer as a whole, figure 2 The edge AB of the middle arc is the illuminated area of ​​the sound beam, and the other arc areas are the sound shadow area.

[0080] It can be obtained from the geometrical acoustic theory that the point L is the intersection point of OO' and AB, which is a...

Embodiment 3

[0129] Below in conjunction with concrete example, table 1-table 4, carry out feasibility verification to the scheme in embodiment 1 and 2, see the following description for details:

[0130] According to the center fitting method given in the above-mentioned examples 1 and 2, the experimental signal is used for calculation to verify the accuracy of the proposed method for locating the center of the circle by ultrasonic detection of buried pipelines. The detailed operation is as follows:

[0131] 1) Use the experimental platform and relevant experimental parameters in step 201 to carry out 7 repeated tests;

[0132] 2) Using the fast energy center convergence method to estimate and compare the TOA of 7 groups of water tank experimental echo signals and simulated echo signals, the results are shown in Table 1;

[0133] 3) use the numerical solution of the method fitting circle center in step 202;

[0134] with |δ x |,|δ y |Represent the error size between the fitted value an...

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Abstract

The invention discloses a circle center positioning method in ultrasonic detection of a shoal buried pipeline. The circle center positioning method is based on a time of arrival and least square method, and comprises the steps of: constructing a simplified bright spot model of the buried pipeline; using a MATLAB to design simulation parameters to obtain a simulated echo signal; constructing a simple single-channel ultrasonic transmitting and receiving experimental platform in a laboratory environment; simulating a shoal complex environment, adding Gaussian noise with a signal-to-noise ratio being a certain threshold value into an original experimental echo signal to obtain an echo signal; performing echo TOA estimation on the echo signal by adopting a maximum amplitude method, a characteristic parameter correlation detection method and a fast energy center convergence method respectively, and selecting the optimal estimation method therefrom; calculating a sonic path distance between atransducer and a theoretical mirror bright spot according to the simplified bright spot model and echo TOA estimation; and fitting a pipeline circle center objective function according to the sonic path distance and calculating an approximate numerical solution, taking the approximate numerical solution as initial coordinates, and calculating a precise solution of the circle center of the pipeline through iterative operation.

Description

technical field [0001] The invention relates to the field of ultrasonic detection of buried pipelines in shoals, in particular to a method for locating the center of pipelines based on time of arrival and the least square method. Background technique [0002] Long oil pipelines buried in shoal areas (rivers, swamps, ponds, rice fields, etc.) are generally laid below 1 to 2 meters of soil. After a leakage accident, conventional pipeline repair cofferdam operations usually have the following three deficiencies: [0003] (1) The scope of cofferdam construction is much larger than the actual required operation area; [0004] (2) If the location of the cofferdam construction deviates from the leakage site, it must be rebuilt; [0005] (3) There are safety risks of collapse and water seepage in traditional cofferdams. [0006] Therefore, if there is an automatic and intelligent machine equipment in cofferdam repair work for oil pipeline leakage, it can accurately locate the pos...

Claims

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Application Information

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IPC IPC(8): G01S15/88G01S7/539F17D5/06
CPCF17D5/06G01S7/539G01S15/88
Inventor 白志亮陈世利谢思捷曾周末
Owner TIANJIN UNIV
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