A fiber optic pipe robot incorporating hydrophones and method of use

Abstract

The application discloses a kind of water hearing combination optical fiber pipeline robot and use method, it is related to pipeline detection and safe operation technical field.The device includes robot body and track in pipe, robot body lower part is connected with track in pipe, can travel along pipe axis high speed;Robot body tail is equipped with vibration exciter, track in pipe is fixed in pipe wall by annular sleeve, and track bottom is laid with distributed optical fiber hydrophone sensor.Robot travels, vibration exciter sequentially crosses annular sleeve and generates active acoustic signal, this signal is used to calculate travel distance according to the number of strokes and sleeve spacing, is also used to identify pipe wall defect by waveform comparison;Distributed optical fiber hydrophone sensor receives acoustic signal synchronously and carries out redundancy check, realizes high-precision positioning;When detecting abnormal acoustic signal, trigger front strobe underwater camera and carry out image review.The application realizes the high-speed, accurate, comprehensive detection of pipeline internal defect by the cooperative work of active acoustic signal excitation and distributed optical fiber hydrophone reception, with the advantages of high positioning accuracy, accurate defect identification, fast detection efficiency and the like.

Description

Technical Field

[0001] This invention belongs to the field of safe operation and maintenance technology of water transmission and regulation projects, and in particular, it relates to a low-cost pipeline defect detection robot that can operate at high speed, and especially to a fiber optic pipeline robot combined with hydrophone and its usage method. Background Technology

[0002] Fiber optic pipeline robots are widely used in the health monitoring of major infrastructure projects such as long-distance water transmission, oil and gas transportation, and urban integrated pipe corridors. They can effectively identify early-stage defects such as corrosion, cracks, leaks, and deformation in pipelines, providing crucial data support for preventative maintenance and emergency repair. However, in practical engineering applications, existing fiber optic pipeline robots and monitoring methods still face the following technical bottlenecks: The first type is vision-based in-pipe inspection technology. However, visual inspection methods have high requirements for water turbidity and lighting conditions within the pipeline. In pipelines operating with water or with poor water quality, the imaging quality drops significantly, making it difficult to identify minute leaks or hidden damage inside the pipe wall. Furthermore, visual inspection can only detect existing defects and cannot provide early warnings for fatigue damage or minute leaks that have not yet penetrated the pipe. The second type is passive acoustic monitoring technology based on distributed optical fibers. Limited by the optical pulse width and demodulation algorithm, it often suffers from positioning errors, and once an abnormal signal is detected, it cannot quickly reach the site for close-range verification. The third type is autonomous in-pipe inspection and fixed-point detection technology. Existing technologies include solutions that combine robotic platforms with acoustic sensors, using robots carrying hydrophones or accelerometers to collect vibration signals from the pipe walls as they move within the pipe. However, these solutions still suffer from limitations such as reliance on odometry for positioning accuracy, lack of active excitation sources, constraints on signal transmission and storage, and low efficiency in single-machine operation.

[0003] In summary, existing technologies lack a pipeline robot system and method capable of active acoustic excitation, precise positioning, distributed fiber optic collaborative verification, and dual-machine collaborative operation to solve technical challenges in pipeline defect detection, such as large positioning errors, numerous signal interferences, and difficulty in identifying hidden damage.

[0004] A review reveals that while there are numerous publicly disclosed patents related to pipeline inspection robots, very few technologies and methods claiming to combine hydrophones with high-speed, low-cost fiber optic pipeline robots are available. Summary of the Invention

[0005] The purpose of this invention is to provide a fiber optic pipeline robot combined with hydrophone and a method of using it, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A fiber optic pipeline robot with hydrophone integration is characterized by comprising a robot body and an internal pipe track for operation, wherein the lower part of the robot body is engaged with the internal pipe track to enable the robot to travel at high speed along the pipe axis; the robot body includes a vibration exciter, a drive wheel, and a signal receiving device; the vibration exciter is located at the tail of the robot body, and the drive wheel is in contact with the upper surface of the internal pipe track.

[0008] Furthermore, the internal track also includes an annular sleeve that is in close contact with the inner wall of the pipe. With the help of a small amount of assembly stress, the internal track is fixed to the inner wall of the pipe, avoiding the impact of traditional drilling or pasting on the pipe and water quality.

[0009] Preferably, the annular sleeve can be an open elastic ring structure with an adjusting bolt at the opening. The diameter of the annular sleeve can be adjusted by tightening the bolt to accommodate pipes of different diameters, while ensuring uniform and controllable assembly stress with the pipe wall.

[0010] Preferably, the surface of the annular sleeve that contacts the inner wall of the pipe is provided with annular grooves or raised textures to increase the friction coefficient and prevent axial slippage of the track during long-term use.

[0011] Preferably, the material of the annular sleeve is stainless steel spring steel or high-elasticity polymer, which has good corrosion resistance and fatigue resistance, and is suitable for long-term humid or water-immersed environments inside pipelines.

[0012] Furthermore, the annular sleeve also includes an acoustic signal excitation function. When the robot body travels at high speed along the pipe axis, its vibration exciter generates an active acoustic signal each time it passes the annular sleeve. This active acoustic signal has a dual function: firstly, it is used to record the robot body's travel distance, with the number of strokes recorded in the signal receiving device. The distance traveled by the robot body can be calculated based on the number of strokes and the spacing of the annular sleeves; secondly, it is used to identify pipeline defects. When the pipe wall is damaged, the active acoustic signal generated by the vibration exciter is significantly different from that of an intact pipe wall. The differences in the active acoustic signals generated by different annular sleeves can be analyzed to determine the location of the pipeline defect.

[0013] Furthermore, the vibration exciter is made of wear-resistant hard alloy or ceramic material, and its end that contacts the annular sleeve is designed as a spherical or arc surface to reduce frictional resistance when passing through the sleeve, while ensuring that a clear and stable acoustic signal pulse is generated each time it passes through.

[0014] Preferably, the connection between the vibration exciter and the robot body is provided with an elastic buffer structure to absorb the impact vibration when passing through the collar, so as to avoid the impact being transmitted to the robot body and affecting the stable operation of other components.

[0015] Furthermore, the drive wheel is made of wear-resistant rubber or polyurethane material, and the wheel surface is provided with anti-slip patterns to ensure that it can still provide sufficient driving force on wet or sediment-containing track surfaces, preventing mileage calculation errors caused by slippage.

[0016] Preferably, the drive wheel is equipped with an encoder to record the number of wheel rotations in real time and compare it with the distance calculated from the number of scratches, thereby further improving positioning accuracy.

[0017] Furthermore, a distributed fiber optic hydrophone sensor is installed at the bottom of the track inside the pipe. The active sound signals can be transmitted to the demodulator in real time for analysis, or compared and analyzed with those stored in the signal receiving device. The distributed fiber optic hydrophone sensor is laid along the entire pipeline, forming a continuous sound signal acquisition array, which can record and demodulate all active sound signals generated during the robot's movement, achieving dual acquisition and cross-verification of signals.

[0018] Preferably, the distributed fiber optic hydrophone sensor employs phase-sensitive optical time-domain reflectometry or a Bragg grating array to achieve high-sensitivity, high-resolution distributed measurement of acoustic signals.

[0019] Preferably, the distributed fiber optic hydrophone sensor is encapsulated in a flexible sheath, which is fixed to the bottom of the track inside the tube by a slot or adhesive method, ensuring a tight fit between the fiber optic cable and the track, while also facilitating installation and maintenance.

[0020] Preferably, the distributed fiber optic hydrophone sensor is provided with fiber optic connectors or couplers at regular intervals along the pipeline direction, which are used to connect to the demodulator in sections when needed to achieve segmented detection or fault location.

[0021] Furthermore, the signal receiving device includes a hydrophone or accelerometer for receiving the sound wave signal generated by the vibration exciter passing through the annular sleeve, and converting the analog signal into a digital signal for storage or transmission.

[0022] Preferably, the signal receiving device further includes a signal preprocessing module for filtering, amplifying, and performing analog-to-digital conversion on the acquired raw acoustic signal, eliminating background noise interference, and extracting effective signal features.

[0023] Furthermore, the robot body can be equipped with a flash-type underwater camera at the front, used to take supplementary photos of the pipe wall in front when abnormal active acoustic signals are received, recording possible pipe wall defects. The camera adopts a high-speed shutter and supplementary lighting design, which can clearly capture images of the pipe wall surface during the robot's high-speed movement. The image data is associated and stored with the corresponding acoustic signal data and position information to form an integrated audio-visual chain of evidence of defects.

[0024] Preferably, the underwater camera, when used with a high-brightness LED fill light, can capture clear images of the pipe wall in low-light, high-turbidity underwater environments.

[0025] Preferably, the underwater camera is equipped with an automatically opening and closing protective cover. When not shooting, the protective cover is closed to protect the lens from water flow impact and impurity abrasion; when shooting is triggered, the protective cover opens quickly and closes automatically after shooting is completed.

[0026] Preferably, the shooting triggering method of the flash underwater camera includes two types: active triggering and passive triggering. Active triggering is triggered by the signal receiving device at preset sampling intervals; passive triggering is triggered in real time by the abnormal sound signal detection results, so as to realize targeted verification of suspected defect locations.

[0027] Furthermore, the robot body can be composed of two robots forming a unit. Robot 1 moves forward and generates active sound signals, while robot 2 follows behind, replacing the signal receiving device with a storage device for capturing and storing image data. In the dual-robot collaborative working mode, robot 1 focuses on sound signal excitation and initial acquisition, while robot 2 is responsible for high-definition image capture and massive data storage. This clear division of labor improves detection efficiency and data quality.

[0028] Preferably, the No. 1 robot and the No. 2 robot in the dual-robot unit communicate with each other via wired or wireless means to synchronize their travel speed and position information in real time and maintain a set following distance.

[0029] Preferably, the second robot is also equipped with a backup power module, which can provide emergency power support to the first robot during the testing process and extend the continuous working time of the unit.

[0030] Furthermore, the fiber optic pipeline robot, combined with hydrophone technology, utilizes pre-embedded distributed fiber optic hydrophone sensors and a series of airborne acquisition systems to achieve high-speed acquisition of defects within the pipeline. The entire system forms a detection process of "active excitation - distributed reception - airborne recording - image verification," enabling rapid, accurate, and comprehensive detection of internal pipeline defects.

[0031] Preferably, the internal track is laid along the entire pipeline, and adjacent track sections are connected by quick connectors. The connectors are designed with guide structures to ensure that the robot passes through the connector positions smoothly.

[0032] Preferably, the internal track is equipped with specially designed transition sections at special locations such as pipe bends, tees, and diameter changes. The track shape and clamp spacing of the transition sections are customized according to the actual direction and size of the pipe to ensure that the robot can still pass normally in complex pipe sections.

[0033] Preferably, the robot body is also equipped with a positioning beacon transmitter, and corresponding beacon receivers are set at key positions on the track inside the tube. When the robot passes by, the beacon position is recorded to calibrate the cumulative mileage error based on the number of strokes.

[0034] Preferably, the device also includes a remote monitoring and control system, which is connected to the robot body via cable or underwater wireless communication, receives detection data in real time, and can send control commands to the robot, such as adjusting the travel speed or triggering the camera to take pictures.

[0035] Preferably, the remote monitoring system also includes a data storage and analysis platform, which fuses the received acoustic signal data, image data, and location data to automatically generate a pipeline health inspection report, identify the location, type, and severity of defects, and provide maintenance recommendations.

[0036] A method for using a fiber optic pipeline robot combined with hydrophone, characterized by comprising the following steps:

[0037] S1. Select a matching annular sleeve according to the inner diameter of the pipe to be tested, fix the inner track of the pipe to the inner wall of the pipe through the annular sleeve, and record the installation distance L of each annular sleeve as the distance reference.

[0038] Preferably, before step S1, a step of cleaning the inner wall of the pipe is included, using high-pressure water jet or mechanical brush to remove the deposits on the pipe wall, ensuring close contact between the annular sleeve and the pipe wall and smooth movement of the robot.

[0039] Preferably, in step S1, an initial acoustic calibration is also performed when installing the annular sleeves. That is, without the robot passing by, each annular sleeve is struck in turn with a standard hammer, and its acoustic response is recorded as the standard waveform of the sleeve, which is used to eliminate the differences caused by different sleeves due to manufacturing differences or different installation stresses.

[0040] S2. Place the robot body on the track inside the tube. The drive wheel drives the robot to move at high speed along the tube axis. During the movement, the vibration exciter at the tail passes through each ring hoop in sequence, generating an active sound signal pulse each time it passes through.

[0041] Preferably, in step S2, the robot's travel speed can be adjusted according to the detection requirements. A higher speed is used when performing a full-line rapid inspection, and the speed is reduced or paused when a suspected defect is found that requires fine inspection, so as to collect sound signals from multiple angles and capture images.

[0042] Preferably, in step S2, when using a dual-machine unit, the first robot and the second robot maintain a set distance. The first robot is responsible for generating the sound signal, while the second robot synchronously collects the sound signal and image from behind, thus achieving redundant signal acquisition and complete image capture.

[0043] S3. The signal receiving device records the number of strokes N and calculates the travel distance of the robot body according to the formula D=N×L. At the same time, the distributed fiber optic hydrophone receives the active sound signal, and the demodulator demodulates the sound signal waveform and compares it bidirectionally with the data recorded by the signal receiving device.

[0044] Preferably, in step S3, the data comparison between the signal receiving device and the distributed fiber optic hydrophone sensor adopts a timestamp alignment method, matching the acoustic signal events recorded by both according to their occurrence time, marking events that fail to match, and subsequently processing them through manual review or algorithm reanalysis.

[0045] S4. Compare the waveform of the active acoustic signal excited at each annular sleeve with the standard waveform:

[0046] S41. If the waveform characteristics are consistent with the standard waveform, the pipe wall at that location is determined to be intact.

[0047] S42. If the waveform shows amplitude attenuation, frequency shift or phase change, it is determined that there is a pipe wall defect. Record the number of scratches N corresponding to the abnormal waveform, and calculate the precise location of the defect according to the distance formula in S3.

[0048] Preferably, in step S4, the standard waveform is dynamically updated by averaging the waveforms that were determined to be intact in the previous few tests and using them as the standard waveform for the current test, so as to adapt to the slow changes in the acoustic characteristics of the pipeline caused by factors such as temperature changes and pressure fluctuations.

[0049] S43. Perform cluster analysis on the abnormal waveforms of multiple consecutive annular sleeves to determine the defect type as local pitting, circumferential crack or longitudinal crack.

[0050] S5. When S42 detects an abnormal signal, it triggers the front-mounted flash underwater camera to take supplementary photos and record the appearance of the abnormal pipe wall. The image data is stored in association with the corresponding acoustic signal data and location information.

[0051] Preferably, in step S5, the shooting parameters of the flash underwater camera are automatically adjusted according to the robot's travel speed and the turbidity of the water in the pipe, including shutter speed, supplementary light intensity and shooting frequency, to ensure that clear images of the pipe wall can be obtained under different working conditions.

[0052] Preferably, the method further includes a periodic re-inspection step, in which the same pipeline is repeatedly inspected at regular intervals, and the acoustic signal waveforms and image data from each inspection are compared to analyze the evolution trend of defects and predict the remaining life of the pipeline.

[0053] Beneficial effects of this invention:

[0054] Compared with the prior art, the fiber optic pipeline robot and its usage method combined with hydrophone provided by the present invention have the following beneficial effects:

[0055] 1. This invention generates active acoustic signals through the mechanical friction between a vibration exciter and an annular sleeve, achieving integrated functionality for measuring travel distance and identifying pipe wall defects. This solves the technical problems of traditional pipeline robots relying on wheeled odometers, which are prone to slippage and have large positioning errors. Each time the vibration exciter rubs against the annular sleeve, it generates an acoustic pulse. The signal receiving device records the number of pulses and, combined with the preset sleeve spacing, accurately calculates the travel distance. Simultaneously, a distributed fiber optic hydrophone sensor receives the acoustic signals for verification.

[0056] 2. This invention uses the elastic assembly stress of a ring-shaped clamp to fix the internal track to the inner wall of the pipe, eliminating the need for drilling holes or using adhesives. This protects the integrity of the pipe structure and avoids pollution of the transported water by chemical adhesives. The ring-shaped clamp adopts an open elastic ring structure and is equipped with adjusting bolts, allowing for adaptive adjustment according to different pipe diameters. This ensures uniform and controllable assembly stress. Simultaneously, the contact surface between the clamp and the pipe wall is textured with anti-slip grooves to prevent axial slippage of the track under long-term use or water flow impact, improving the long-term operational reliability of the system.

[0057] 3. This invention utilizes a dual acquisition mechanism of distributed fiber optic hydrophone sensors and an airborne signal receiving device to achieve coordinated operation of full-line recording of active acoustic signals and airborne backup, thus mitigating the risk of data loss due to equipment failure or transmission interruption that may occur with a single acquisition method. The fiber optic hydrophone sensors are laid along the entire pipeline, continuously demodulating all active acoustic signals generated during the robot's movement to ensure the integrity and accuracy of the detection data.

[0058] 4. This invention achieves the organic integration of acoustic detection and visual verification through a linkage triggering mechanism between a flash underwater camera and abnormal acoustic signals, solving the technical problem of false alarms caused by environmental interference in single-sensor detection. When the signal receiving device detects an abnormal acoustic signal, it immediately triggers the front camera to perform supplementary lighting imaging of the pipe wall in front, storing the acoustic signal characteristics and the appearance image of the pipe wall.

[0059] 5. This invention separates the acoustic signal excitation and acquisition functions from the image capture and storage functions through a dual-machine collaborative operation mode. The first robot focuses on high-speed movement and acoustic signal excitation, while the second robot follows behind to be responsible for high-definition capture and data storage. This solves the contradiction between movement speed and data acquisition quality when operating with a single machine, and improves detection efficiency and data quality. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the tube track installation structure of the present invention.

[0061] Figure 2 This is a schematic diagram of the appearance of the fiber optic pipeline robot of the present invention.

[0062] Figure 3 This is a schematic diagram of the fiber optic pipeline robot of the present invention moving on the track inside the pipe.

[0063] Figure 4 This is a schematic diagram of the No. 1 fiber optic pipeline robot of the present invention.

[0064] Figure 5 This is a schematic diagram of the second fiber optic pipeline robot of the present invention.

[0065] Figure 6 This is a schematic diagram of the operation of a set of fiber optic pipeline robots according to the present invention.

[0066] Figure 7 This is a flowchart illustrating the method of using a fiber optic pipeline robot combined with hydrophone according to the present invention.

[0067] In the diagram: 100, pipe; 200, annular sleeve; 300, distributed fiber optic hydrophone sensor; 400, internal track; 500, robot body; 510, vibration exciter; 520, drive wheel; 530, signal receiving device; 540, storage device; 550, flash underwater camera. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] It should be understood that the fiber optic sensor, demodulator, and flash underwater camera used in this invention are all mature products, and their mechanisms are widely known. They are not the innovative points of this invention, nor are they the content claimed by this patent.

[0070] First Embodiment

[0071] To address the problems of existing pipeline robots, such as reliance on odometers for positioning accuracy, lack of active excitation sources, and low single-machine operation efficiency, this embodiment details the specific structural composition and detection implementation method of a fiber optic pipeline robot combined with hydrophones. Figure 1 , Figure 2 , Figure 3 , Figure 7 As shown.

[0072] (1) Pipe (100) is the water supply pipe to be inspected, with an inner diameter of 1200mm and a prestressed concrete cylinder pipe (PCCP). Before inspection, the inner wall of the pipe is cleaned by high-pressure water jet to remove attached mud and biofilm, and to ensure that the annular sleeve (200) fits tightly with the pipe wall.

[0073] (2) The inner track (400) is made of aluminum alloy profiles in sections, each 2m long, and connected into a continuous track by quick connectors. The bottom of the track has a groove along the longitudinal direction for laying distributed fiber optic hydrophone sensors (300). The upper surface of the track is flat and 80mm wide for robot movement. The track is fixed to the inner wall of the pipe (100) by annular clamps (200). The annular clamps (200) are made of stainless steel spring steel strips, with an open structure and adjusting bolts at the opening. During installation, the bolts are tightened according to the inner diameter of the pipe to generate assembly stress and tighten the clamps to the pipe wall. The installation distance L between adjacent annular clamps (200) is set to 1.5m as a distance reference. The contact surface between the clamp and the pipe wall is machined with annular grooves to increase friction and prevent slippage.

[0074] (3) The distributed fiber optic hydrophone sensor (300) uses a phase-sensitive optical time-domain reflectometry (TDR) optical cable, which is encapsulated in a flexible sheath and fixed to the groove at the bottom of the track by a slot. An optical fiber connector is reserved every 500m of the optical cable to facilitate segmented access to the demodulator. The demodulator is placed outside the pipe, with a sampling rate of 10kHz and a spatial resolution of 1m.

[0075] (4) The robot body (500) consists of an aluminum alloy shell, drive wheels (520), vibration exciter (510), signal receiving device (530), and a flash underwater camera (550). There are four drive wheels (520), made of polyurethane material, with anti-slip patterns on the wheel surface. They are driven by a DC brushless motor with a maximum travel speed of 1 m / s. The drive wheels are equipped with photoelectric encoders to record the number of wheel rotations. The vibration exciter (510) is located at the tail of the robot, made of hard alloy, with a spherical end, and is pressed against the upper surface of the track by a spring. When the robot moves, the vibration exciter (510) passes through each annular collar (200) in sequence, generating mechanical impact sound signals. The signal receiving device (530) includes a piezoelectric hydrophone and a signal preprocessing circuit, installed inside the robot, and is used to receive sound signals and convert them into digital signals for storage. The flash underwater camera (550) is installed at the front of the robot and is equipped with an LED fill light and a protective cover.

[0076] (5) Inspection process

[0077] S1. Install the inner track (400) on the inner wall of the pipe (100) section by section using the annular sleeve (200), and record the installation spacing of each annular sleeve. After installation, perform initial calibration: use a standard hammer to strike each annular sleeve (200) in sequence, record its sound response as the standard waveform of the sleeve, and store it in the signal receiving device (530) and demodulator.

[0078] S2. Place the robot body (500) at the starting end of the track, start the drive wheel (520), and the robot moves along the pipe axis at a speed of 0.8 m / s. During the movement, the vibration exciter (510) sequentially passes over the annular collar (200), generating an active sound signal pulse with each pass. The signal receiving device (530) records the number of passes N in real time and calculates the travel distance according to D=N×L. At the same time, the distributed fiber optic hydrophone (300) receives all active sound signals, the demodulator demodulates the sound signal waveform, and compares it bidirectionally with the data recorded by the signal receiving device (530) through timestamp alignment to eliminate the mileage error caused by wheel slippage. If the two data fail to match, the event is marked for review.

[0079] S3. Compare the active acoustic signal waveform generated at each annular sleeve (200) with the calibrated standard waveform. If the waveform characteristics are consistent, the pipe wall at that location is considered intact; if the waveform shows amplitude attenuation or obvious phase change, the pipe wall at that location is considered defective. Record the number of scratches corresponding to the abnormal waveform and calculate the precise location of the defect.

[0080] S4. When S3 detects an abnormal signal, it immediately triggers the front-mounted flash underwater camera (550) to take supplementary photos and record the appearance of the abnormal pipe wall. The camera automatically adjusts the shutter speed according to the robot's travel speed. The image data, along with the corresponding acoustic signal data and position information, are stored in the local memory.

[0081] S5. After the inspection is completed, export all data to the analysis platform and identify the location, type, and severity of defects. For pipelines that require repeated inspections, the internal track (400) can be left in place for long-term use for subsequent periodic inspections.

[0082] Second Embodiment

[0083] To address the issue of mutual constraints between acoustic signal acquisition and image capture in single-robot detection, resulting in lower detection efficiency, this embodiment proposes a dual-robot collaborative working mode, such as... Figure 4 , Figure 5 , Figure 6 As shown.

[0084] (1) The unit consists of two robot bodies: Robot No. 1 (500) is equipped with a vibration exciter (510), drive wheel (520), and signal receiver (530) and is responsible for high-speed movement and active sound signal excitation; Robot No. 2 (500) is equipped with drive wheel (520), flash underwater camera (550), and large-capacity storage device (540) and is responsible for lagging behind and capturing images and storing data. The two robots synchronize their movement speed and position information in real time through a wireless communication module and maintain the set following distance.

[0085] (2) The original signal receiving device of the second robot was replaced with a storage device (540) with a capacity of 2TB, which can store 10 hours of continuous high-definition video and audio signal data. The second robot is also equipped with a hydrophone for synchronously receiving audio signals to form redundant acquisition.

[0086] (3) Inspection process

[0087] S1. Same as step S1 in the first embodiment, complete the track installation and calibration.

[0088] S2. Robot No. 1 moves forward at a speed of 1.0 m / s. The vibration exciter (510) sequentially sweeps across the annular collar (200) to generate active sound signals. The signal receiving device (530) records the number of sweeping sounds and transmits them to Robot No. 2 in real time. Robot No. 2 follows behind at the same speed, lagging by 10 m. Its underwater camera (550) automatically takes pictures of the pipe wall at preset intervals. At the same time, the hydrophone synchronously collects sound signals and stores them in the storage device (540).

[0089] S3. When Robot 1 detects an abnormal sound signal, it immediately notifies Robot 2 via wireless communication. Robot 2 adjusts its camera shooting parameters to focus on shooting the abnormal area and continuously collects images within a 2m range before and after the abnormal location.

[0090] S4. After the inspection is completed, the acoustic signal data of robot No. 1 is compared with that of robot No. 2 to confirm signal consistency; the images captured by robot No. 2 are associated with the abnormal location to generate an inspection report with image evidence. Dual-machine collaboration improves inspection speed while ensuring high-resolution image acquisition.

[0091] Third Embodiment

[0092] To address the problem that conventional straight tracks cannot pass through complex structures such as bends, diameter changes, and tees in pipelines, this embodiment proposes a track and robot design adapted to complex pipe sections.

[0093] (1) The pipe track (400) adopts segmented prefabricated curved rails at the bends, with the radius of curvature consistent with the pipe bends. The track cross-section remains flat, but the bottom fiber optic groove is correspondingly bent. Guide joints are provided at both ends of the curved rails to smoothly connect with the front and rear straight rails. The annular sleeves (200) are densely arranged at the bends, with the spacing shortened to 1.0m, to enhance the stability of the track in the curved section.

[0094] (2) In the pipe section with a change in diameter, a transition track with a change in diameter is used. The track width remains unchanged, but the bottom is equipped with adjustable support legs to keep the upper surface of the track level, which facilitates the robot's movement. The annular sleeve (200) is selected according to the inner diameter of the pipe after the change in diameter.

[0095] (3) At T-junctions or junctions, a turnout mechanism is installed on the track to switch directions, allowing the robot to select different branches according to instructions. A beacon receiver is installed at the turnout location, and the positioning beacon transmitter on the robot triggers a position record when it passes by, which is used to calibrate the mileage accumulation error.

[0096] (4) The robot body (500) and drive wheels (520) adopt an independent suspension structure. Each wheel can adapt to the slight undulations of the track through springs to ensure that all four wheels are always in contact with the track. An elastic buffer structure is added at the connection between the vibration exciter (510) and the robot body to reduce the impact when turning.

[0097] (5) Inspection process

[0098] S1. Based on the pipeline design drawings, prefabricate the track sections for complex pipe sections and install them on-site. Install beacon receivers at key locations such as elbows, reducers, and tees, and record their mileage.

[0099] S2. After the robot starts, it travels along the preset path. When it passes the beacon receiver, the positioning beacon transmitter is triggered, the robot records the current position, and compares it with the mileage calculated based on the number of swipes. If the deviation exceeds 0.5m, the accumulated mileage value is automatically corrected.

[0100] S3. At the bend, the robot automatically reduces its travel speed to 0.3 m / s to ensure that the vibration exciter (510) can still clearly pass through the annular collar (200) to generate an effective acoustic signal. The fiber optic hydrophone sensor (300) synchronously collects the signal, and the demodulator locates the position based on the optical delay and verifies it with the robot's mileage to ensure accurate positioning of the bend defect.

[0101] S4. After the inspection is completed, the curved rails and variable diameter rails can be disassembled as needed, while the straight rails can be retained for subsequent inspections, or all of them can be retained as permanent monitoring channels.

Claims

1. A fiber optic pipeline robot incorporating hydrophone, characterized in that, Includes a robot body (500) and an inner tube track (400) required for operation. The lower part of the robot body (500) is engaged with the inner tube track (400) to enable the robot to move at high speed along the tube axis. The robot body (500) includes a vibration exciter (510), a drive wheel (520) and a signal receiving device (530); the vibration exciter (510) is located at the tail of the robot body (500), and the drive wheel (520) is in contact with the upper surface of the tube track (400).

2. The fiber optic pipeline robot combined with hydrophone according to claim 1, characterized in that, The inner track (400) also includes an annular sleeve (200) that is in close contact with the inner wall of the pipe (100). With the help of a small amount of assembly stress, the inner track (400) is fixed to the inner wall of the pipe (100), avoiding the impact of traditional drilling or pasting on the pipe and water quality.

3. The fiber optic pipeline robot combined with hydrophone according to claim 1, characterized in that, The annular sleeve (200) also includes an acoustic signal excitation function. When the robot body (500) moves at high speed along the pipe axis, its vibration exciter (510) generates an active acoustic signal every time it passes the annular sleeve (200). The active sound signal is used to record the travel distance of the robot body (500). The number of scratches is recorded in the signal receiving device (530). The length of the robot body (500) can be calculated based on the number of scratches and the spacing of the ring sleeve (200). The active acoustic signal is also used to identify defects in the pipe (100). When the pipe wall is damaged, the active acoustic signal generated by the vibration exciter (510) is significantly different from that of an intact pipe wall. The differences in the active acoustic signals generated by different annular sleeves (200) can be analyzed to determine the location of the defect in the pipe (100).

4. The fiber optic pipeline robot combined with hydrophone according to claim 1, characterized in that, The bottom of the tube track (400) is equipped with a distributed fiber optic hydrophone sensor (300). The active acoustic signal can be transmitted to the demodulator in real time for analysis, or it can be compared and analyzed with the signal receiving device (530).

5. The fiber optic pipeline robot combined with hydrophone according to claim 1, characterized in that, The robot body (500) can also be equipped with a flash underwater camera (550) at the front, which is used to take supplementary photos of the pipe wall in front when receiving abnormal active sound signals, and record possible pipe wall defects.

6. The fiber optic pipeline robot combined with hydrophone according to claim 1, characterized in that, The robot body (500) can be composed of two robots. The first robot moves forward and generates active sound signals, while the second robot is located behind it. The signal receiving device (530) is replaced with a storage device (540) for taking pictures and storing image data.

7. A fiber optic pipeline robot combined with hydrophone according to claim 1, characterized in that, The aforementioned fiber optic pipeline robot, which incorporates hydrophones, enables high-speed acquisition of defects within the pipeline through pre-embedded distributed fiber optic hydrophone sensors (300) and a series of onboard acquisition systems.

8. A method for using a fiber optic pipeline robot combined with hydrophone, characterized in that, Includes the following steps: S1. Select a matching annular sleeve (200) according to the inner diameter of the pipe (100) to be tested, fix the inner rail (400) to the inner wall of the pipe (100) through the annular sleeve (200), and record the installation distance L of each annular sleeve (200) as the distance reference. S2. Place the robot body (500) on the inner track (400) of the tube. Drive wheel (520) drives the robot to move at high speed along the tube axis. During the movement, the vibration exciter (510) at the tail passes through each ring sleeve (200) in sequence, generating an active sound signal pulse each time it passes through. S3. The signal receiving device (530) records the number of strokes N and calculates the travel distance of the robot body (500) according to the formula D=N×L. At the same time, the distributed fiber optic hydrophone (300) receives the active sound signal, and the demodulator demodulates the sound signal waveform and compares it bidirectionally with the data recorded by the signal receiving device (530). S4. Compare the waveform of the active acoustic signal excited at each annular sleeve (200) with the standard waveform: S41. If the waveform characteristics are consistent with the standard waveform, the pipe wall at that location is determined to be intact. S42. If the waveform shows amplitude attenuation, frequency shift or phase change, it is determined that there is a pipe wall defect. Record the number of scratches N corresponding to the abnormal waveform, and calculate the precise location of the defect according to the distance formula in S3. S43. Perform cluster analysis on the abnormal waveforms of multiple consecutive annular sleeves (200) to determine the defect type as local pitting, circumferential crack or longitudinal crack. S5. When S42 detects an abnormal signal, it triggers the front-mounted flash underwater camera (550) to perform supplementary lighting and capture images of the abnormal pipe wall. The image data is then stored in association with the corresponding acoustic signal data and location information.

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