Non-contact submarine pipeline deformation measuring method

Abstract

The invention belongs to the technical field of energy conveying, pipeline maintenance and nondestructive testing, and discloses a non-contact submarine pipeline deformation measuring method. According to the seabed turbidity, an adaptive piezoelectric wafer is selected to weaken the influence of tide or seabed turbidity on measurement; through an RS485 bus, the MCU converts an underwater front-end distance value from an analog quantity to a digital quantity and remotely transmits the digital quantity to a portable work station on an offshore mobile platform, so that the remote transmission anti-interference capability of a detection value is improved; a bent pipeline scanning device is used for carrying an ultrasonic detection front end to realize radial distance measurement of a pipeline, and a distance value is converted into diameter change so as to reflect pipeline deformation; in combination with the axial translation interval delta x and the circumferential rotation interval delta alpha, the distance value d is converted into point cloud data under a three-dimensional coordinate system, then three-dimensional curved surface reconstruction is conducted on the point cloud data, and the pipeline deformation quantity can be visually reflected.

Description

Technical Field

[0001] The invention belongs to the technical field of energy transmission, pipeline maintenance and non-destructive testing, and in particular relates to a non-contact submarine pipeline deformation measurement method. Background Art

[0002] The main failure forms of submarine pipelines are buckling, fatigue and rupture. Usually, submarine pipelines operate under high temperature and high pressure conditions (close to or exceeding 10MPa, close to or exceeding 100℃), and are subject to the main loads of temperature and pressure, which produce great stress in the axial and circumferential directions of the pipeline. Axial stress is difficult to release through the elongation of the pipeline itself, but it is easy to release it in the vertical or horizontal direction, that is, buckling deformation occurs. At the same time, due to the scouring of submarine tides, submarine pipelines will also experience drift, bending, sinking deformation caused by external forces.

[0003] For submarine pipeline observation, non-contact detection methods mainly include acoustic method and optical measurement method. Among them, the side scanning sonar based on acoustic method can detect the distribution of submarine pipelines or depth measurement, but it is not used to detect pipeline buckling and deformation; based on optical method, ROV / AUV carries underwater camera or laser radar to detect pipeline morphology, but the measurement accuracy is greatly affected by underwater turbidity. Summary of the invention

[0004] The purpose of the present invention is to provide a non-contact method for measuring the deformation of a submarine pipeline. According to the actual situation of the seabed turbidity, an adaptive piezoelectric chip is selected to weaken the influence of tide or seabed turbidity on the measurement. The low-frequency ultrasonic excitation / receiving stage, the amplification and filtering stage, the detection stage, the A / D acquisition, the MCU and the RS485 sending / receiving module are arranged at the detection front end (constituting the detection sensor front end), and the influence of the distributed capacitance between the transmission line and the seawater on the analog model is reduced to a minimum, the common mode rejection ratio is improved, and then the signal-to-noise ratio is improved. Using three-dimensional surface reconstruction, the point cloud data of the pipeline deformation is reconstructed to form a three-dimensional model of the pipeline morphology, which can vividly and intuitively reflect the pipeline deformation.

[0005] The present invention provides a non-contact submarine pipeline deformation measurement method. The device used in the measurement method is composed of a detection sensor front end, an RS485 to USB module, a control server, a curved pipeline scanning device and a portable workstation. The low-frequency ultrasonic sensor module (piezoelectric chip and damping block), a low-frequency ultrasonic excitation / receiving stage, an amplification and filtering stage, a detection stage, an A / D acquisition, an MCU and an RS485 sending / receiving module are waterproof and sealed to form the detection sensor front end.

[0006] The specific measurement steps are as follows:

[0007] 1) According to the seabed turbidity, calculate the wavelength λ, near-field length N, and half-diffusion angle θ of the ultrasonic wave excited by the piezoelectric chip, make λ much larger than the diameter of the turbid particles, select the appropriate piezoelectric chip, and match it with the damping block to form a low-frequency ultrasonic sensor module;

[0008] 2) The front end of the detection sensor is fixed in the sensor bracket in the curved pipe scanning device, and the portable workstation controls the sensor bracket to execute the scanning trajectory through the control server;

[0009] 3) The portable workstation adjusts the excitation pulse width, excitation voltage, repetition frequency, gain of the amplification and filtering stages, and RS485 bus transmission baud rate of the excitation stage in the low-frequency ultrasonic excitation / receiving stage through the RS485 to USB module;

[0010] 4) Under the detection parameter configuration of step 3), the excitation stage in the low-frequency ultrasonic excitation / receiving stage excites the low-frequency ultrasonic sensor module with the predetermined parameter configuration, and the ultrasonic echo signal is received by the low-frequency ultrasonic receiving stage, and the signal is amplified, filtered, and detected in sequence, and then converted into a digital quantity by A / D acquisition;

[0011] 5) MCU calculates the distance value carried by the ultrasonic echo signal, that is, d = v*T / 2, d is the distance value, v is the ultrasonic sound speed in water, and T is the round-trip time of ultrasonic propagation;

[0012] 6) The MCU transmits the distance value obtained in step 5) to the portable workstation on the offshore operating platform via the RS485 to USB module;

[0013] 7) At the detection time interval, the portable workstation obtains the axial translation interval Δx and the number of steps N1, the circumferential rotation angle Δα and the number of steps N2 from the control server, and the host computer software binds d, the axial translation x=Δx·N1, the circumferential rotation angle α=Δα·N2, and converts them into three-dimensional coordinates;

[0014] 8) Repeat step 7) until the detection is completed;

[0015] 9) After the detection is completed, the overall detection data of the pipeline deformation is converted into point cloud data, and the three-dimensional surface reconstruction is completed to form a pipeline deformation reconstruction model.

[0016] The non-contact submarine pipeline deformation measurement method provided by the present invention comprises the following steps: Near field length Half diffusion angle Make λ much larger than the diameter of the turbid particles, and take into account the diffraction of the sound wave and the directivity of the sound beam, and choose the appropriate piezoelectric chip, where D s is the diameter of the piezoelectric chip, c is the speed of ultrasound in water, and f is the frequency of ultrasound.

[0017] In the non-contact submarine pipeline deformation measurement method provided by the present invention, in the step 3), the excitation pulse width in the low-frequency ultrasonic excitation / receiving module is 0.5 or 1.0 or 2.5 us; the excitation voltage is 50 or 100 V; and the repetition frequency is 100 or 200 or 500 kHz.

[0018] In the non-contact submarine pipeline deformation measurement method provided by the present invention, the gain parameters of the amplification and filtering stages in step 3) are -20 to 60 dB, with an increment of 0.5 dB; the gain is controlled by the MCU module to realize program-controlled amplification of ultrasonic signals.

[0019] In the non-contact submarine pipeline deformation measurement method provided by the present invention, in the step 3), the RS485 bus transmission baud rate is 4800 or 9600 or 115200 Baud, and the MCU transmits the distance value carried by the ultrasonic echo signal to a portable workstation on the offshore operating platform, thereby eliminating common mode interference, improving the common mode rejection ratio, and further improving the anti-interference ability of data transmission.

[0020] The non-contact submarine pipeline deformation measurement method provided by the present invention realizes radial distance measurement of the pipeline by using the front end of the detection sensor carried by the curved pipeline scanning device, converts x, α and d into point cloud numbers (X, Y, Z) in a three-dimensional coordinate system, X=x, Y=R1·cosα, Z=(R2-d)·sinα, and finally obtains the overall point cloud data of the outer surface of the pipeline, and then reconstructs the three-dimensional surface of the point cloud data, which can intuitively reflect the pipeline deformation amount, and the deformation resolution is 1 cm; wherein x is the axial translation, α is the circumferential rotation angle, d is the distance value, R1 is the pipeline radius, and R2 is the scanning radius of the sensor bracket of the curved pipe scanning device.

[0021] The present invention also provides an application of the method for non-contact measurement of deformation of a submarine pipeline, by measuring the pipeline deformation (ie, the distance value d) and then binding the corresponding x and α to achieve three-dimensional visualization of the pipeline deformation.

[0022] The present invention has the following advantages:

[0023] 1) According to the actual underwater turbidity situation, select the appropriate piezoelectric chip and damping block, low-frequency ultrasonic excitation energy, and receiving amplification gain to improve the detection sensitivity.

[0024] 2) The buckling deformation point cloud data of the pipeline outer surface is reconstructed into three-dimensional surface. By comparing and analyzing the reconstructed model with the CAD model, the buckling deformation of the pipeline can be intuitively reflected, and the deformation resolution is 1 cm.

[0025] 3) Integrate the ultrasonic receiving / amplifying and other post-processing circuits into the detection front end and transmit the ranging value through the RS485 bus to reduce the influence of parasitic capacitance on the analog signal and improve the signal-to-noise ratio.

[0026] 4) The detection repetition frequency is adjustable from 200Hz to 1kHz to meet high and low speed detection needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the principle block diagram of the non-contact submarine pipeline deformation measurement system;

[0028] Figure 2 A schematic diagram of the detection path planning for the detection sensor;

[0029] Figure 3 Measure point cloud data for pipe outer surface deformation;

[0030] Figure 4 Reconstructed map of the buckling deformation in the local inspection area of ​​the pipeline. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0032] Embodiment 1:

[0033] The present invention provides a non-contact submarine pipeline deformation measurement method. The device used in the measurement method is composed of a detection sensor front end, an RS485 to USB module, a control server, a curved pipeline scanning device and a portable workstation. Among them, a low-frequency ultrasonic sensor module (piezoelectric chip and damping block), a low-frequency ultrasonic excitation / receiving stage, an amplification and filtering stage, a detection stage, an A / D acquisition, an MCU and an RS485 sending / receiving module are waterproof and sealed to form a detection sensor front end ( Figure 1 ).

[0034] The above device system was used to conduct a segmented detection experiment on a submarine pipeline in a turbid sea area in the East China Sea. The outer diameter of the submarine pipeline is 508mm. The detection trajectory is as follows: Figure 2 The specific detection parameters are shown in Table 1.

[0035] Table 1 Segment detection system parameter configuration

[0036] project parameter Excitation voltage(V) 50 Excitation pulse width (us) 1 Repetition rate (kHz) 0.2 Probe frequency (kHz) 200 Gain(dB) 35 Baud rate 4800 Axial translation interval Δx (mm) 10 Axial rotation interval Δα(°) 15 Detection time interval (s) 0.5

[0037] The detection steps of the above system for detecting the deformation of submarine pipelines in turbid waters are described in detail. The specific steps are as follows:

[0038] 1) According to the seabed turbidity, calculate the wavelength λ, near-field length N, and half-diffusion angle θ of the ultrasonic wave excited by the piezoelectric chip, make λ much larger than the diameter of the turbid particles, select the appropriate piezoelectric chip, and match it with the damping block to form a low-frequency ultrasonic sensor module;

[0039] 2) Fix the front end of the detection sensor in the sensor bracket of the curved pipe scanning device. The portable workstation controls the sensor bracket to execute the scanning trajectory through the control server. The detection trajectory is as follows: Figure 2 As shown;

[0040] 3) The portable workstation adjusts the excitation pulse width, excitation voltage, repetition frequency, gain of the amplification and filtering stages, and RS485 bus transmission baud rate of the excitation stage in the low-frequency ultrasonic excitation / receiving stage through the RS485 to USB module;

[0041] 4) Under the detection parameter configuration of step 3), the excitation stage in the low-frequency ultrasonic excitation / receiving stage excites the low-frequency ultrasonic sensor module with the predetermined parameter configuration, and the ultrasonic echo signal is received by the low-frequency ultrasonic receiving stage, and the signal is amplified, filtered, and detected in sequence, and then converted into a digital quantity by A / D acquisition;

[0042] 5) MCU calculates the distance value carried by the ultrasonic echo signal, that is, d = v*T / 2, d is the distance value, v is the ultrasonic sound speed in water, and T is the round-trip time of ultrasonic propagation;

[0043] 6) The MCU transmits the distance value obtained in step 5) to the portable workstation on the offshore operating platform via the RS485 to USB module;

[0044] 7) At the detection time interval, the portable workstation obtains the axial translation interval Δx and the number of steps N1, the circumferential rotation angle Δα and the number of steps N2 from the control server. The host computer software binds d, the axial translation x = Δx·N1, the circumferential rotation angle α = Δα·N2, and converts them into three-dimensional coordinates, such as Figure 3 As shown;

[0045] 8) Repeat step 7) until the detection is completed;

[0046] 9) After the detection is completed, the overall detection data of the pipeline deformation is converted into point cloud data, and the three-dimensional surface reconstruction is completed to form a pipeline deformation reconstruction model, such as Figure 4 shown.

[0047] Matters not covered by the present invention are known technologies.

[0048] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A non-contact method for measuring deformation of a submarine pipeline, characterized in that: The device used in this measurement method consists of a detection sensor front end, an RS485 to USB module, a control server, a curved pipe scanning device, and a portable workstation; Among them, the low-frequency ultrasonic sensor module (piezoelectric chip and damping block), low-frequency ultrasonic excitation / receiving stage, amplification and filtering stage, detection stage, A / D acquisition, MCU and RS485 sending / receiving module are waterproof and sealed to form the detection sensor front end; The specific measurement steps are as follows: 1) According to the seabed turbidity, calculate the wavelength λ, near-field length N, and half-diffusion angle θ of the ultrasonic wave excited by the piezoelectric chip, make λ much larger than the diameter of the turbid particles, select the appropriate piezoelectric chip, and match it with the damping block to form a low-frequency ultrasonic sensor module; 2) The front end of the detection sensor is fixed in the sensor bracket in the curved pipe scanning device, and the portable workstation controls the sensor bracket to execute the scanning trajectory through the control server; 3) The portable workstation adjusts the excitation pulse width, excitation voltage, repetition frequency, gain of the amplification and filtering stages, and RS485 bus transmission baud rate of the excitation stage in the low-frequency ultrasonic excitation / receiving stage through the RS485 to USB module; 4) Under the detection parameter configuration of step 3), the excitation stage in the low-frequency ultrasonic excitation / receiving stage excites the low-frequency ultrasonic sensor module with the predetermined parameter configuration, and the ultrasonic echo signal is received by the low-frequency ultrasonic receiving stage, and the signal is amplified, filtered, and detected in sequence, and then converted into a digital quantity by A / D acquisition; 5) MCU calculates the distance value carried by the ultrasonic echo signal, that is, d = v*T / 2, d is the distance value, v is the ultrasonic sound speed in water, and T is the round-trip time of ultrasonic propagation; 6) The MCU transmits the distance value obtained in step 5) to the portable workstation on the offshore operating platform via the RS485 to USB module; 7) At the detection time interval, the portable workstation obtains the axial translation interval Δx and the number of steps N1, the circumferential rotation angle Δα and the number of steps N2 from the control server, and the host computer software binds d, the axial translation x=Δx·N1, the circumferential rotation angle α=Δα·N2, and converts them into three-dimensional coordinates; 8) Repeat step 7) until the detection is completed; 9) After the detection is completed, the overall detection data of the pipeline deformation is converted into point cloud data, and the three-dimensional surface reconstruction is completed to form a pipeline deformation reconstruction model.

2. The non-contact submarine pipeline deformation measurement method according to claim 1 is characterized in that: The ultrasonic wavelength is calculated in step 1) Near field length Half diffusion angle Make α much larger than the diameter of the turbid particles, and take into account the diffraction of the sound wave and the directivity of the sound beam, and choose the appropriate piezoelectric chip, where D s is the diameter of the piezoelectric chip, c is the speed of ultrasound in water, and f is the frequency of ultrasound.

3. The non-contact submarine pipeline deformation measurement method according to claim 1 is characterized in that: In the step 3), the excitation pulse width in the low-frequency ultrasonic excitation / receiving module is 0.5 or 1.0 or 2.5 us; the excitation voltage is 50 or 100 V; and the repetition frequency is 100 or 200 or 500 kHz.

4. The non-contact submarine pipeline deformation measurement method according to claim 1 is characterized in that: In the step 3), the gain parameters of the amplification and filtering stages are -20 to 60 dB, with an increment of 0.5 dB; the gain is controlled by the MCU module to achieve program-controlled amplification of the ultrasonic signal.

5. The non-contact submarine pipeline deformation measurement method according to claim 1 is characterized in that: In the step 3), the RS485 bus transmission baud rate is 4800 or 9600 or 115200 Baud, and the MCU transmits the distance value carried by the ultrasonic echo signal to the portable workstation on the offshore operating platform to eliminate common mode interference, improve the common mode rejection ratio, and thus improve the anti-interference ability of data transmission.

6. The non-contact submarine pipeline deformation measurement method according to claim 1 is characterized by: The curved pipe scanning device is used to carry the detection sensor front end to realize the radial distance measurement of the pipeline, and x, α and d are converted into point cloud numbers (X, Y, Z) in the three-dimensional coordinate system, X=x, Y=R1·cosα, Z=(R2-d)·sinα, and finally the overall point cloud data of the outer surface of the pipeline is obtained. Then the point cloud data is reconstructed into a three-dimensional surface, which can intuitively reflect the deformation of the pipeline with a deformation resolution of 1 cm; among them, x is the axial translation, α is the circumferential rotation angle, d is the distance value, R1 is the pipeline radius, and R2 is the scanning radius of the sensor bracket of the curved pipe scanning device.

7. An application of the method according to any one of claims 1 to 6 for non-contact measurement of deformation of a submarine pipeline, by measuring the pipeline deformation (distance value d) and then binding the corresponding x and α to achieve three-dimensional visualization of the pipeline deformation.

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