Flexible net body state online perception monitoring system and method

Abstract

The application relates to the technical field of flexible net body structure state monitoring, and discloses a flexible net body state online perception monitoring system and method. The system comprises a flexible net body, a plurality of optical fiber composite sensing cables, a watertight optical fiber jointing box, a multi-core transmission optical cable, an optical fiber demodulator, a data processing module and a state identification display terminal. The optical fiber composite sensing cable is fused with the net body weaving, the integration of the flexible net body bearing structure and the sensing structure is realized, and the problems of internal strain distribution unable to be continuously and online perceived and abnormal positioning unclear are solved.

Description

Technical Field

[0001] This application relates to the field of flexible mesh structure status monitoring technology, and in particular to an online sensing and monitoring system and method for the status of flexible mesh structures. Background Technology

[0002] With the rapid development of marine engineering and water conservancy facilities, flexible nets are widely used in numerous scenarios such as nuclear power plant cold source intake interception, hydropower station or pumping station intake debris interception, river floating debris interception, and marine aquaculture. As the first physical barrier for underwater protection, flexible nets are constantly subjected to complex and variable hydrodynamic environments, continuously enduring water flow impacts, wave fluctuations, tidal changes, and the impact of various floating objects, facing extremely high operational safety pressures. To ensure the safe and stable operation of flexible net structures and prevent foreign objects from intruding into critical facilities due to net failure, it is urgent to conduct comprehensive and accurate monitoring of their stress and deformation states under complex operating conditions.

[0003] Furthermore, in existing technologies, underwater visual or acoustic detection techniques are often used to obtain the spatial morphology of the net, by deploying cameras and sonar equipment underwater to image the outline of the net from the outside. However, visual monitoring is easily affected by water turbidity, low light, and biological attachment under high current speeds, and acoustic detection mainly reflects the external outline and cannot penetrate to obtain the internal stress state. As a result, in complex marine environments (such as the cold source intake of a nuclear power plant), the image recognition effect is poor, and it is impossible to directly obtain the true strain state of the internal load-bearing components such as the main rigging and side rigging of the net. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to propose an online sensing and monitoring system and method for the state of a flexible net body, so as to solve the problem that the prior art cannot continuously sense the actual stress and strain distribution in each region inside the flexible net body online.

[0005] To achieve the above and other related objectives, the present invention provides an online sensing and monitoring system for the state of a flexible network based on fiber optic sensing, comprising: The flexible net body includes a main frame and side frames for bearing the overall tensile load, and reinforcing ribs for improving local stiffness and transmitting the force of the net. Multiple fiber optic composite sensing cables are laid on the key load-bearing paths of the flexible mesh body. The fiber optic composite sensing cables directly participate in the mesh weaving as at least one of the main strand, the side strand, or the reinforcing rib. Watertight fiber optic splice box, used to converge optical signals; Multi-core optical fiber cables are used for long-distance transmission; fiber optic demodulators are used to transmit and receive optical signals and analyze wavelength or phase changes. The data processing module is used for data cleaning and algorithm analysis; Status recognition and display terminal, used for status assessment and visual early warning.

[0006] In a specific embodiment of the present invention, the optical fiber composite sensing cable comprises, from the inside out: The sensing fiber is located at the very center; A tight-cladding layer tightly covering the outside of the sensing optical fiber; A reinforcing layer disposed on the outside of the tight-fitting layer; Fixed-point coupling structures are spaced apart along the length of the optical cable, and the fixed-point coupling structures are used to limit the relative slippage between the optical cable and the outer braided layer; Outer sheath layer; The outer braided load-bearing layer is made of multiple strands of high-strength fiber rope wrapped around the outside of the outer sheath layer.

[0007] In a specific embodiment of the present invention, the sensing fiber is a fiber Bragg grating, a weak fiber grating array, or a distributed sensing fiber. The reinforcing layer is made of steel wire, aramid, or fiber reinforcement; the outer sheath is made of polyethylene or polyurethane.

[0008] In a specific embodiment of the present invention, the outer braided load-bearing layer adopts a 6-strand or 8-strand symmetrical braided topology, so that the sensing optical fiber at the very center is always located at the geometric neutral axis of the cross section.

[0009] In a specific embodiment of the present invention, the optical fiber composite sensing cable is arranged on the flexible mesh body in the manner of main load-bearing sensing cable and zone sensing cable to form a plurality of interconnected sensing squares, each sensing square corresponding to at least one optical fiber measuring point or optical fiber segment.

[0010] In a specific embodiment of the present invention, when the flexible net body is a planar net, multiple optical fiber composite sensing cables are respectively laid out along the horizontal and vertical directions to form multiple interconnected sensing squares; when the flexible net body is a three-dimensional net bag, the optical fiber composite sensing cables are laid out along the opening, tail, vertical and circumferential directions of the net bag to divide the three-dimensional net bag into multiple spatial sensing areas.

[0011] In one specific embodiment of the present invention, multiple single-core sensing optical fibers inside each of the flexible mesh bodies converge in the same watertight optical fiber splice box, convert and output a multi-core transmission optical cable; multiple flexible mesh bodies each use a single multi-core transmission optical cable as an independent monitoring module, and are connected in parallel to the same optical fiber demodulator.

[0012] In a specific embodiment of the present invention, the data processing module establishes a spatial channel mapping relationship between the network body number, splice box number, channel number, measurement point number and the sensing grid based on the access channel of the multi-core transmission optical cable.

[0013] In a specific embodiment of the present invention, the data processing module uses strain-free compensating fiber optic measuring points for temperature compensation to calculate the actual axial strain of each measuring point.

[0014] In a specific embodiment of the present invention, the state recognition display terminal operates a three-dimensional deformation reconstruction algorithm to convert the one-dimensional strain data of each sensing grid boundary cable into spatial curvature, and reconstruct the deformation surface equation of the flexible net body in three-dimensional space through integration.

[0015] In a specific embodiment of the present invention, the state recognition display terminal performs overall blockage diagnosis, local blockage or foreign object attachment diagnosis, mesh damage or loose connection diagnosis, and posture abnormality diagnosis logic based on the strain change characteristics and regional strain difference of different regions.

[0016] This invention also provides an online sensing and monitoring method for the status of a flexible mesh, applied to an online sensing and monitoring system for the status of a flexible mesh based on fiber optic sensing. The system includes fiber optic composite sensing cables deployed on the flexible mesh body and forming multiple sensing squares. The method includes: To obtain the raw wavelength or phase data output by the fiber optic demodulator; Temperature compensation is applied to the original wavelength or phase data to calculate the actual axial strain at each measuring point. The one-dimensional strain data of the boundary cables of each sensing grid are converted into spatial curvature, and the deformation surface equation of the flexible mesh body in three-dimensional space is reconstructed by integration. Based on the strain change characteristics and strain difference of different regions, execute the abnormal state diagnosis logic.

[0017] The technical advantages of this invention are as follows: By directly using multiple fiber optic composite sensing cables as at least one of the main strands, side strands, or reinforcing ribs in the weaving of the net, this application abandons traditional external or isolated end-mounted monitoring methods, achieving a high degree of integration between the load-bearing structure and the sensing structure of the flexible net. Because the sensing elements and the actual load-bearing skeleton of the net are integrated in physical space and mechanical transmission, every inch of the net's load-bearing network possesses self-sensing capabilities, overcoming the blind spot defects of traditional end-mounted monitoring that rely on point measurements. This solution enables maintenance personnel to grasp the real strain distribution at any location within the net in real time, continuously, and quantitatively, thereby enabling timely detection and accurate location of risks such as local blockages, damage, or abnormal posture of the net. Simultaneously, by combining a spatial three-dimensional deformation reconstruction algorithm and abnormal state diagnosis logic, this application achieves visualized reconstruction from one-dimensional optical signals to three-dimensional spatial states and intelligent identification of fault types, providing a reliable, intuitive, and intelligent monitoring method for the safe operation of flexible nets in complex hydrodynamic environments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an optical fiber composite sensing cable provided in an optional embodiment of this application; Figure 2 This is a cross-sectional view of an optical fiber composite sensing cable provided in an optional embodiment of this application; Figure 3 This is a structural diagram of the flexible net body status online sensing and monitoring system provided in an optional embodiment of this application.

[0020] Explanation of reference numerals in the attached figures: 1. Sensing fiber; 2. Outer sheath layer; 3. External braided load-bearing layer; 4. Reinforcing layer; 11. Fiber optic composite sensing cable; 12. Watertight fiber optic splice box; 13. Fiber optic demodulator; 14. Status recognition and display terminal. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0022] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and its component layout may also be more complex.

[0023] Flexible netting is widely used in scenarios such as cold water intake interception in nuclear power plants and pollution control in hydropower stations. In actual operation, flexible netting is subjected to the combined effects of multiple factors, including water flow, tidal currents, waves, floating debris impacts, and biological attachment. Related technologies typically employ manual inspection, underwater video observation, or tension gauges installed at the netting ends to monitor the netting's safety status. However, manual inspection and video observation are limited by underwater visibility and adverse sea conditions, making 24 / 7 online monitoring impossible; and end tension gauges can only obtain concentrated force data at the connection points between the netting boundary and anchorages.

[0024] Existing monitoring methods cannot continuously and online sense the true stress and strain distribution in different regions within a flexible mesh. The root cause of this technical deficiency lies in the fact that traditional monitoring elements (such as tension gauges) are physically independent of the actual load-bearing framework of the mesh, belonging to "externally attached" or "end-isolated" monitoring. Due to the extreme flexibility of the flexible mesh, when a local blockage occurs in the center of the mesh or the mesh is damaged, the stress will undergo a complex redistribution within the mesh, resulting in extremely weak changes in tension transmitted to the end tension gauges or significant time lags.

[0025] Based on the above technical logic, see Figures 1 to 3 In some embodiments, this application provides an online sensing and monitoring system for the status of a flexible network based on fiber optic sensing. The system includes: a flexible network body, a multi-fiber composite sensing cable 11, a watertight fiber optic splice box 12, a multi-core transmission fiber optic cable, a fiber optic demodulator 13, a data processing module, and a status recognition and display terminal 14.

[0026] Specifically, the flexible net body is the physical foundation of the entire system. The flexible net body includes main and side strands for bearing the overall tensile load, and reinforcing ribs for improving local stiffness and transmitting the force on the net. The main and side strands form the outer skeleton of the net and are directly connected to anchors or floats; the reinforcing ribs are interwoven within the net, responsible for converting the planar impact force of the water flow into linear tensile force and transmitting it to the outer skeleton.

[0027] Multiple fiber optic composite sensing cables 11 are deployed along the critical load-bearing paths of the flexible mesh body. Unlike the externally attached sensors used in related technologies, in this embodiment, the fiber optic composite sensing cables 11 directly participate in the mesh weaving as at least one of the main strand, the side strand, or the reinforcing rib. This means that while the fiber optic composite sensing cables 11 withstand hydrodynamic tension, their internal optical fibers simultaneously sense extremely small axial strains.

[0028] The watertight fiber optic splice box 12 is used to converge optical signals. Since multiple fiber optic composite sensing cables 11 are deployed on the flexible mesh body, the single-core optical fibers inside these cables need to be physically converged underwater. The watertight fiber optic splice box 12 provides a high-strength waterproof sealing environment, coupling and outputting multiple single-core optical signals.

[0029] Multi-core optical fiber cable is used for long-distance transmission. One end is connected to the watertight optical fiber splice box 12, and the other end extends out of the water and to the shore-based control room, transmitting the converged optical signal to the back-end resolution equipment with low loss.

[0030] The fiber optic demodulator 13 is used to transmit and receive optical signals and analyze wavelength or phase changes. The fiber optic demodulator 13 transmits a broadband light source or pulsed laser to the multi-core transmission optical cable and receives the optical signals reflected or scattered back by the fiber optic composite sensing cable 11 in real time. Through the internal optical interference or spectral analysis module, the wavelength or phase shift at each physical measurement point is analyzed at high frequency.

[0031] The data processing module is used for data cleaning and algorithm analysis. This module receives the raw optical data output by the fiber optic demodulator 13, performs operations such as temperature compensation and filtering to reduce noise, and converts optical parameters into mechanical strain parameters.

[0032] The status recognition and display terminal 14 is used for status assessment and visual early warning. It receives strain data output from the data processing module, runs relevant algorithms to reconstruct the net body morphology, judges the health status of the net body according to preset logic, and finally outputs the visual results and alarm information on the screen.

[0033] Through the aforementioned basic implementation method, this application achieves a high degree of integration between the load-bearing structure and the sensing structure of the flexible net. When the net is impacted by floating objects or experiences partial blockage, the force is transmitted through the net to the fiber optic composite sensing cable 11, which acts as a reinforcing rib, and then to the main or side ribs. The optical fibers inside the cable undergo axial stretching, causing a shift in the wavelength of the optical signal. By capturing this subtle optical change, the system can monitor the force state at any location within the net in real time, continuously, and quantitatively.

[0034] In some preferred embodiments, to further address the technical problems of the sensing fiber being easily damaged and strain transmission being easily distorted in complex underwater environments, this application has customized the internal microstructure of the fiber optic composite sensing cable 11 at multiple levels. See [link to relevant documentation] Figure 2 The fiber optic composite sensing cable 11 comprises, from the inside out: a sensing fiber 1 located at the very center; a tight-packing layer tightly covering the outside of the sensing fiber 1; a reinforcing layer 4 disposed on the outside of the tight-packing layer; fixed-point coupling structures spaced apart along the length of the optical cable; an outer sheath layer 2; and an outer braided load-bearing layer 3.

[0035] In the aforementioned cable structure, the sensing fiber 1 is the core of the sensing process. The tight-closing layer, typically made of special resin or plastic, provides the first line of physical protection for the fragile silica glass fiber, absorbing minor lateral impacts. The reinforcing layer 4 is designed to withstand the transient tensile and lateral pressures generated during the cable's manufacturing, transportation, and underwater towing, preventing the sensing fiber 1 from being accidentally broken or crushed.

[0036] Furthermore, the fixed-point coupling structure is a key feature in this embodiment that ensures the fidelity of strain transmission. In composite cables of related technologies, there are often tiny gaps between the inner optical cable and the outer strands. When the outer strand is stretched, the inner optical cable is prone to relative slippage, causing the strain sensed by the sensing fiber 1 to be much smaller than the actual strain. In this embodiment, the fixed-point coupling structure is used to limit the relative slippage between the optical cable and the outer braided layer. This structure can be manifested as protrusions, crimping points, or locally wrapped reinforcement sections periodically arranged along the optical cable axis. Through mechanical interlocking or high-friction engagement, the fixed-point coupling structure forces the macroscopic deformation of the outer braided load-bearing layer 3 to be transmitted to the inner sensing fiber 1 without damage, significantly enhancing the strain transmission efficiency and measurement linearity.

[0037] The outer sheath layer 2 serves as a robust barrier against water and corrosion, isolating it from highly corrosive seawater, silt abrasion, and the adhesion and erosion of marine organisms. The outer braided load-bearing layer 3, composed of multiple strands of high-strength fiber rope wrapped around the outside of the outer sheath layer 2, is the true load-bearing body of the cable, acting as the main structure or reinforcing rib.

[0038] In some more specific embodiments, depending on the monitoring scale and accuracy requirements, the sensing fiber 1 can be a fiber Bragg grating (FBG), a weak fiber Bragg grating array, or a distributed sensing fiber. If the flexible network body is small and only high-frequency dynamic monitoring of key nodes is required, a fiber Bragg grating can be selected; if the network body is large, a distributed sensing fiber is preferred to achieve blind-spot-free coverage. The reinforcing layer 4 uses steel wire, aramid, or fiber reinforcement to balance extremely high tensile strength with the overall flexibility of the cable. The outer sheath layer 2 uses polyethylene (PE) or polyurethane (PU) material, where polyethylene has excellent hydrolysis resistance and polyurethane exhibits excellent abrasion resistance and tear resistance.

[0039] In some preferred embodiments, to address the measurement accuracy issue of the fiber optic composite sensing cable 11 under complex underwater deformation conditions, this application has specifically limited the weaving process of the outer braided load-bearing layer 3. See [link to relevant documentation]. Figure 2 The outer braided load-bearing layer 3 has a six- or eight-strand symmetrical braided topology, so that the sensing optical fiber 1 at the center is always at the geometric neutral axis of the cross section.

[0040] The technical logic behind this feature is as follows: In actual operation, the cable is not only subjected to axial tension but also to severe bending and torsion due to water vortex or wave fluctuations. According to the principles of materials mechanics, when the cable bends, the outer side is under tension and the inner side is under compression. If the sensing fiber 1 deviates from the neutral axis, it will bear additional strain caused by bending, leading to distortion of the demodulated data. This embodiment uses a six-strand or eight-strand symmetrical braided topology to ensure that each strand is symmetrically cross-braided around the center with equal tension and pitch angle. This high degree of geometric and mechanical symmetry ensures that no matter which direction the cable bends, the geometric center of its cross-section always coincides with the mechanical neutral axis. This design maximizes the shielding of crosstalk caused by complex deformations such as bending and torsion on the axial strain measurement of the optical fiber, ensuring that the sensing fiber 1 is only sensitive to pure tensile loads along the cable axis, thereby improving measurement accuracy.

[0041] In some embodiments, in order to achieve accurate spatial positioning of abnormal states inside the flexible mesh, this application defines the topology of the fiber optic composite sensing cable 11 on the mesh. The fiber optic composite sensing cable 11 is arranged on the flexible mesh body in the manner of main load-bearing sensing cable and zone sensing cable, forming multiple interconnected sensing squares, each sensing square corresponding to at least one fiber optic measuring point or fiber optic segment.

[0042] Specifically, the main load-bearing sensing cables are typically positioned at the main and side strands to macroscopically control the overall tension and boundary constraints of the netting; the zone sensing cables are positioned at the reinforcing ribs, extending deep into the core of the netting. The crisscrossing cables physically discretize the continuous netting into multiple independently monitorable "sensing squares." Since the fiber optic demodulator 13 can accurately analyze the strain at any location on the fiber optic cable, the system can establish a correspondence between fiber optic measuring points and specific sensing squares. When a foreign object attaches to a sensing square, the zone sensing cables surrounding that square will experience a sudden change in strain, thus providing a physical structural basis for the precise location of the abnormal area.

[0043] Furthermore, this application provides adaptive deployment schemes for flexible net structures of different shapes. When the flexible net structure is a planar net, multiple optical fiber composite sensing cables 11 are deployed along the horizontal and vertical directions respectively, forming multiple interconnected sensing squares. The horizontal cables mainly sense the normal deflection changes caused by the water flow impact, while the vertical cables mainly sense the net structure's own weight and the longitudinal tension caused by the water flow.

[0044] As an alternative implementation, when the flexible net body is a three-dimensional net bag, its stress state is typical of three-dimensional spatial stress. In this case, the fiber optic composite sensing cable 11 is deployed along the opening, tail, longitudinal direction, and circumferential direction of the net bag, dividing the three-dimensional net bag into multiple spatial sensing areas. The opening and tail cables bear the opening tension and the gravity of the accumulated waste, the longitudinal cable transmits the load, and the circumferential cable resists the radial lateral pressure caused by the expansion of internal waste. This adaptable deployment ensures that the core mechanical transmission path can be covered by the sensing network, whether it is a two-dimensional plane or a three-dimensional structure.

[0045] In some embodiments, to reduce the wiring complexity of joint monitoring of multiple interception networks in large-scale water conservancy projects, this application optimizes the convergence and transmission topology of optical signals. See also Figure 3 Multiple single-core sensing optical fibers 1 within each flexible mesh body converge within the same watertight optical fiber splice box 12, converting and outputting a single multi-core transmission optical cable. Furthermore, each of the multiple flexible mesh bodies uses a single multi-core transmission optical cable as an independent monitoring module, connected in parallel to the same optical fiber demodulator 13.

[0046] This "single-core aggregation - multi-core output - parallel access" topology greatly reduces the number of underwater cables. More importantly, it enables modular and pluggable operation of the system. When a section of the interception network needs to be replaced due to severe damage, it is only necessary to disconnect the connection between the corresponding watertight fiber optic splice box 12 and the multi-core transmission fiber optic cable underwater. This will not interfere with the continuous online monitoring of other parallel network sections, thus improving the maintainability of the large-scale interception network system.

[0047] Based on the aforementioned hardware network topology, the data processing module establishes a spatial channel mapping relationship between the network body number, splice box number, channel number, measurement point number, and the sensing grid, based on the access channel of the multi-core transmission optical cable. Through this mapping relationship, the underlying one-dimensional optical signal can be instantly converted into specific coordinates in macroscopic three-dimensional physical space, realizing structured management and precise addressing of massive monitoring data.

[0048] In some embodiments, to eliminate the interference of underwater ambient temperature changes on mechanical monitoring, the data processing module uses strain-free compensating fiber optic measuring points for temperature compensation to calculate the actual axial strain at each measuring point. Since the wavelength drift of a fiber optic grating is affected by the cross-sensitivity of strain and temperature, this embodiment uses a parallel section of compensating fiber optic cable, free from mechanical tension, to obtain the wavelength drift caused purely by ambient temperature changes. Subtracting this compensation amount from the total wavelength drift at the working measuring points reveals the true mechanical strain, ensuring the objectivity and accuracy of the data.

[0049] After acquiring high-precision actual axial strain, the state recognition display terminal 14 runs a three-dimensional deformation reconstruction algorithm to convert the one-dimensional strain data of the boundary cables of each sensing square into spatial curvature. Through integration, it reconstructs the deformation surface equation of the flexible net body in three-dimensional space. This algorithm utilizes the beam-cable bending theory in materials mechanics, equating discrete linear strain to local bending curvature, and deriving the three-dimensional coordinates of the net surface through spatial integration. This enables the system to render a real-time three-dimensional dynamic color cloud map on the terminal screen, showing the flexible net swaying with the water flow or local bulging, transforming one-dimensional light signals into an intuitive three-dimensional spatial state visualization reconstruction.

[0050] Furthermore, the status recognition display terminal 14 not only displays images, but also performs overall blockage diagnosis, local blockage or foreign object attachment diagnosis, netting damage or loose connection diagnosis, and posture abnormality diagnosis logic based on the strain change characteristics and regional strain differences of different areas. By comparing the data linkage relationship between different sensing squares, the system can automatically infer the specific fault type of the netting, providing accurate decision support for on-site operation and maintenance.

[0051] Based on the same inventive concept as the aforementioned system, in some embodiments, this application also provides an online sensing and monitoring method for the state of a flexible mesh. This method is applied to the aforementioned online sensing and monitoring system for the state of a flexible mesh based on fiber optic sensing, the system comprising fiber optic composite sensing cables 11 deployed on the flexible mesh body and forming multiple sensing squares. The method includes the following steps: Step S1: Acquire the raw wavelength or phase data output by the fiber optic demodulator. The system captures the raw optical data generated by the fiber optic demodulator 13 in real time through the communication interface, serving as the data source for subsequent algorithms.

[0052] Step S2: Perform temperature compensation on the original wavelength or phase data to calculate the actual axial strain at each measuring point.

[0053] Step S3: Convert the one-dimensional strain data of each sensing grid boundary cable into spatial curvature, and reconstruct the deformation surface equation of the flexible mesh body in three-dimensional space through integration.

[0054] Step S4: Execute the abnormal state diagnosis logic based on the strain change characteristics and strain difference of different regions.

[0055] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0056] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

Claims

1. A flexible network state online sensing and monitoring system based on fiber optic sensing, characterized in that, include: The flexible net body includes a main frame and side frames for bearing the overall tensile load, and reinforcing ribs for improving local stiffness and transmitting the force of the net. Multiple fiber optic composite sensing cables are laid on the key load-bearing paths of the flexible mesh body. The fiber optic composite sensing cables directly participate in the mesh weaving as at least one of the main strand, the side strand, or the reinforcing rib. Watertight fiber optic splice box, used to converge optical signals; Multi-core optical fiber cables are used for long-distance transmission; fiber optic demodulators are used to transmit and receive optical signals and analyze wavelength or phase changes. The data processing module is used for data cleaning and algorithm analysis; Status recognition and display terminal, used for status assessment and visual early warning.

2. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 1, characterized in that, The fiber optic composite sensing cable comprises, from the inside out: The sensing fiber is located at the very center; A tight-cladding layer tightly covering the outside of the sensing optical fiber; A reinforcing layer disposed on the outside of the tight-fitting layer; Fixed-point coupling structures are spaced apart along the length of the optical cable, and the fixed-point coupling structures are used to limit the relative slippage between the optical cable and the outer braided layer; Outer sheath layer; The outer braided load-bearing layer is made of multiple strands of high-strength fiber rope wrapped around the outside of the outer sheath layer.

3. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 2, characterized in that, The sensing fiber is a fiber Bragg grating, a weak fiber grating array, or a distributed sensing fiber. The reinforcing layer is made of steel wire, aramid, or fiber reinforcement; the outer sheath is made of polyethylene or polyurethane.

4. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 2, characterized in that, The outer braided load-bearing layer uses a 6-strand or 8-strand symmetrical braided topology, ensuring that the central sensing fiber is always positioned at the geometric neutral axis of the cross section.

5. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 1, characterized in that, The fiber optic composite sensing cables are arranged on the flexible mesh body in the manner of main load-bearing sensing cables and zone sensing cables, forming multiple interconnected sensing squares. Each sensing square corresponds to at least one fiber optic measuring point or fiber optic segment.

6. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 5, characterized in that, When the flexible net body is a planar net, multiple fiber optic composite sensing cables are laid out along the horizontal and vertical directions to form multiple interconnected sensing squares; when the flexible net body is a three-dimensional net bag, the fiber optic composite sensing cables are laid out along the opening, tail, vertical and circumferential directions of the net bag to divide the three-dimensional net bag into multiple spatial sensing areas.

7. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 5, characterized in that, Multiple single-core sensing optical fibers inside each of the flexible mesh bodies converge in the same watertight optical fiber splice box, convert and output a multi-core transmission optical cable; multiple flexible mesh bodies each use a single multi-core transmission optical cable as an independent monitoring module, and are connected in parallel to the same optical fiber demodulator.

8. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 7, characterized in that, The data processing module establishes a spatial channel mapping relationship between the network body number, splice box number, channel number, measurement point number and the sensing grid based on the access channel of the multi-core transmission optical cable.

9. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 5, characterized in that, The data processing module uses strain-free compensating fiber optic measuring points for temperature compensation to calculate the actual axial strain at each measuring point.

10. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 9, characterized in that, The state recognition display terminal operates a three-dimensional deformation reconstruction algorithm, which converts the one-dimensional strain data of the boundary cables of each sensing square into spatial curvature, and reconstructs the deformation surface equation of the flexible net body in three-dimensional space through integration.

11. The flexible network status online sensing and monitoring system based on fiber optic sensing according to claim 10, characterized in that, The status recognition and display terminal performs overall blockage diagnosis, local blockage or foreign object attachment diagnosis, mesh damage or loose connection diagnosis, and posture abnormality diagnosis logic based on the strain change characteristics and regional strain differences of different areas.

12. A method for online sensing and monitoring of the status of a flexible mesh, applied to an online sensing and monitoring system for the status of a flexible mesh based on fiber optic sensing, the system comprising fiber optic composite sensing cables deployed on the flexible mesh body and forming multiple sensing squares, characterized in that, The method includes: To obtain the raw wavelength or phase data output by the fiber optic demodulator; Temperature compensation is applied to the original wavelength or phase data to calculate the actual axial strain at each measuring point. The one-dimensional strain data of the boundary cables of each sensing grid are converted into spatial curvature, and the deformation surface equation of the flexible mesh body in three-dimensional space is reconstructed by integration. Based on the strain change characteristics and strain difference of different regions, execute the abnormal state diagnosis logic.

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