Intelligent composite cable based on modal isolation and preparation method thereof

Abstract

The invention discloses an intelligent composite cable based on modal isolation and a preparation method thereof. The cable comprises a power transmission layer, a control signal layer, an optical fiber communication layer and an intelligent protection and external shielding layer which are sequentially arranged from inside to outside. The power transmission layer comprises a conductor layer, a conductor insulation layer and a first shielding layer for attenuating a low-frequency strong magnetic field which are sequentially arranged from inside to outside; the control signal layer comprises a total shielding layer and a plurality of control wire cores which are uniformly arranged between the total shielding layer and the power transmission layer along the circumferential direction, and each control wire core is provided with a branch shielding layer; the optical fiber communication layer comprises a plurality of optical fiber groups which are uniformly arranged along the circumferential direction, each optical fiber group is provided with a second shielding layer for electric absorption, and the second shielding layer is a non-metal shielding layer; the intelligent protection and external shielding layer is provided with a third shielding layer used for equipotential shielding. According to the invention, a layered composite structure is adopted, the reliability of mechanical performance is ensured, and an asymmetric shielding framework is adopted, so that full-spectrum interference suppression from extremely low frequency to high frequency is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cables, in particular to an intelligent composite cable based on modal isolation and a preparation method thereof. BACKGROUND

[0002] With the rapid development of intelligent manufacturing, industrial internet and automated production lines, modern industrial equipment puts forward higher requirements for the transmission performance, integration and reliability of cables. Traditional cable systems usually adopt a discrete wiring scheme, i.e. power cables, control cables and optical fibers are laid separately, which leads to inherent disadvantages such as large space occupation, serious signal interference and high maintenance cost. In response to the above problems, the industry has begun to study composite cable technology that integrates multiple functions in one, however, the existing composite cable technology still has the following serious defects and technical bottlenecks to be solved: (1) Insufficient shielding effectiveness and incomplete frequency spectrum coverage: Existing technologies mostly use simple shielding layer stacking (such as aluminum foil + copper wire braid) or homogenized shielding design. This design only has a certain effect on high-frequency electromagnetic interference (EMI), but has very weak suppression ability for low-frequency strong magnetic fields (50 / 60Hz and harmonics) generated by power lines.

[0003] (2) Poor dynamic mechanical reliability: The existing structure simply combines rigid metal materials (such as shielding layers), brittle materials (such as optical fibers) and flexible polymers, and the mechanical properties (modulus, elasticity) between layers are severely mismatched. In high-frequency bending and twisting dynamic applications, internal shear stress is easily generated.

[0004] (3) Inherent conflict between grounding and compatibility design: The full-metal shielding layer is easy to form a complex ground loop, and the potential difference between different grounding points will introduce ground loop interference, which is fatal to control signals.

[0005] Therefore, the intelligent composite cable in the prior art is mostly a "patched" integration, which fails to truly solve a series of systematic problems such as interference coordination suppression and mechanical property matching. SUMMARY

[0006] The present application aims to overcome the deficiencies of the prior art by providing an intelligent composite cable based on modal isolation and a preparation method thereof. The layered composite structure is adopted to ensure mechanical property reliability, and the asymmetric shielding architecture is adopted to achieve full-spectrum interference suppression from very low frequency to high frequency, thereby completely solving the signal distortion problem caused by the coexistence of high and low frequency interference in complex industrial environments, and providing an ultimate solution for high-reliability data transmission.

[0007] The technical solution for achieving the purpose of the present application is: The application discloses a smart composite cable based on modal isolation, which comprises a power transmission layer, a control signal layer, an optical fiber communication layer and a smart protection and external shielding layer arranged in sequence from inside to outside; the power transmission layer comprises a conductor layer, a conductor insulation and a first shielding layer for attenuating low-frequency strong magnetic field arranged in sequence from inside to outside; the control signal layer comprises a total shielding layer and a plurality of control line cores arranged uniformly along the circumference between the total shielding layer and the power transmission layer, and the control line core is provided with a partial shielding layer; the optical fiber communication layer comprises a plurality of optical fiber groups arranged uniformly along the circumference, and the optical fiber group is provided with a second shielding layer for electric absorption, and the second shielding layer is a non-metal shielding layer; and the smart protection and external shielding layer is provided with a third shielding layer for equipotential shielding.

[0008] Further, the conductor layer is formed by tightly pressing a plurality of wires with a fan-shaped cross section, the conductor insulation is a ceramicized silicone rubber insulation layer, and the first shielding layer adopts a high-permeability nanocrystalline alloy belt and is formed into a continuous magnetic flux path through a longitudinal laser seamless welding process.

[0009] Further, the optical fiber group further comprises an elastic buffer layer, a stainless steel tube and a plurality of optical fiber units which are sequentially sleeved in the second shielding layer, and the gap between the optical fiber unit and the stainless steel tube is filled with water-blocking ointment.

[0010] Further, the second shielding layer is a carbon nanotube gradient distribution polymer-based composite material layer.

[0011] Further, the smart protection and external shielding layer further comprises an outer sheath wrapped outside the third shielding layer and a conformal smart sensing layer and a high-strength aramid yarn braiding layer which are sequentially arranged in the third shielding layer, and the braiding density of the high-strength aramid yarn braiding layer is greater than or equal to 95%, and the tensile strength is greater than or equal to 3000N.

[0012] Further, the conformal smart sensing layer comprises a sensing optical fiber which is pasted on the outer surface of the high-strength aramid yarn braiding layer in a sinusoidal wave path through coating of flexible adhesive, and the sensing optical fiber is engraved with an FBG grating.

[0013] Further, an isolation layer is arranged outside the conformal smart sensing layer, so that the conformal smart sensing layer is wrapped, fixed and protected flatly, is isolated from the third shielding layer, is prevented from short circuit or abrasion, and the isolation layer is made of flexible TPU or PE material.

[0014] Further, the third shielding layer is a silver-plated nylon filament braiding layer, and the braiding angle of the silver-plated nylon filament braiding layer is 55-65°.

[0015] Further, the outer sheath is made of thermoplastic polyurethane added with a halogen-free environment-friendly flame retardant, and has a continuous corrugated annular structure in cross section.

[0016] Further, the height difference between the trough and the crest of the outer sheath is 0.8-1.2 mm, and the corrugation pitch is 10-15 mm.

[0017] Further, the continuous corrugation of the annular structure forms an array of grooves extending in the axial direction on the inner wall of the outer sheath, the cross section of the grooves is semicircular or trapezoidal, the depth is 0.2-0.3 mm, the width is 0.5-1 mm, and the distance between adjacent grooves is 3-5 mm.

[0018] A preparation method of a smart composite cable based on modal isolation, for preparing the smart composite cable as described above, specifically comprising the following steps: Step S1: preparing a power transmission layer, a control line core and an optical fiber group respectively; Step S2: overall cabling, using a concentric twisting device, twisting the prepared power transmission layer, the control line core and the optical fiber group in a synchronous manner according to the structure design requirements, and wrapping with a water-blocking tape to form a cable core; adjusting the wire laying tension of each unit in real time through an online tension monitoring system to ensure that the twisted body structure is compact and round, and the concentricity deviation of each layer is less than ±0.1 mm; Step S3: preparing a smart protection and external shielding layer; The twisted cable core is passed through a high-speed braiding machine to tightly braid high-strength aramid yarn outside the cable core, and the braiding density is ≥95% to form a high-strength aramid yarn braiding layer as a load-bearing layer that bears the main tensile strength; The cable core is guided through a programmable eccentric guide roller to guide the sensing optical fiber with the FBG array to make a precise sinusoidal path around the high-strength aramid yarn braiding layer for one round, and the low-modulus flexible adhesive is synchronously and uniformly coated on the surface of the sensing optical fiber and the high-strength aramid yarn braiding layer, and the adhesive is quickly cured through a UV curing furnace to firmly "paste" and shape the sensing optical fiber on the surface of the load-bearing layer; The cable core with the attached sensing layer is passed through another high-speed braiding machine to braid silver-plated nylon filaments outside the cable core to form a third shielding layer with electromagnetic shielding and physical protection functions; then a plastic extruder is used to extrude a thermoplastic polyurethane material, and a halogen-free environmentally friendly flame retardant is blended into the material by a double-screw blending technology, a corrugated mold corresponding to the structure design of the cable is installed at the outlet of the plastic extruder to form a corrugated outer sheath as the outermost layer.

[0019] By adopting the above technical scheme, the present application has the following beneficial effects: (1) The asymmetric shielding architecture of the present application innovatively combines the first shielding layer for magnetic shielding, the second shielding layer for electric absorption and the third shielding layer for equipotential shielding, breaking through the limitations of traditional single shielding technology, realizing full-spectrum interference suppression from extremely low frequency to high frequency, and completely solving the signal distortion problem caused by the coexistence of high and low frequency interference in complex industrial environments, providing an ultimate solution for high reliability data transmission; at the same time, the power line core is taken as the center, the control line core is arranged around the power line core in the circumferential direction, and the optical fiber group is arranged around the control line core layer to form a multi-layer bundle, which simplifies the cable process, and the overall structure is compact, high integration, and the wiring is more reasonable, compared with the traditional design, more than 60% of the space is saved, which helps the miniaturization and lightweight design of the equipment.

[0020] (2) The present application adopts a plurality of fan-shaped section conductors to form a conductor layer with a circular cross section, which takes into account the space utilization and flexibility under the premise of the same conductor cross-sectional area, and adopts a high-permeability nanocrystalline alloy strip with an initial relative magnetic permeability μ i ≥80000, which can efficiently attenuate low-frequency strong magnetic field interference.

[0021] (3) The optical fiber group of the present application adopts a stainless steel tube loose sleeve structure as the core protection and accommodation structure of the internal optical fiber, and fills with waterproof ointment, which can block water and also play a buffering and chemical protection role; by setting an elastic buffer layer, external vibration and impact energy can be effectively absorbed and dispersed, preventing force from being directly transmitted to the optical fiber, when the cable is bent, the layer deforms to provide space for the internal stainless steel tube, avoiding excessive strain on the optical fiber, thereby solving the mechanical mismatch problem.

[0022] (4) The present application adopts a carbon nanotube gradient design to realize the transition from high reflection inside to high absorption outside, efficiently suppress high-frequency electromagnetic interference, as a non-metal shielding layer, fundamentally eliminating the grounding loop interference problem caused by the metal shielding layer, and at the same time, as the outermost sheath of the optical fiber group, providing preliminary physical and environmental protection for the internal elastic buffer layer and optical fiber unit.

[0023] (5) The present application adopts a high-strength aramid yarn braiding layer to bear most of the axial tension generated during cable operation and installation, ensuring that the internal precise functional line core (such as the optical fiber group and the control line core) is in a "zero tension" or low tension state, and is free from stress damage, and at the same time, its flexible braiding structure provides radial buffering for the internal line core, resisting external impact and extrusion, forming a tensile buffer layer; in addition, by setting a conformal intelligent sensing layer between the high-strength aramid yarn braiding layer and the third shielding layer, on the one hand, the sensing signal is fully protected from external electromagnetic interference, and on the other hand, the strain of the high-strength aramid yarn braiding layer can be most directly sensed, so that the overall tension and bending stress of the cable can be more accurately monitored.

[0024] (6) The sensing optical fiber is engraved with FBG gratings, real-time sensing of the surface temperature distribution of the cable is realized, overheat early warning is realized, the temperature measurement accuracy is ±0.5 DEG C, combined with the OTDR technology, vibration, impact and other events along the cable length can be positioned and recognized, meanwhile, the laying mode of the sine wave is adopted, so that the axial tension and bending strain are extremely sensitive, the overload tension, bending radius and vibration state of the cable can be accurately monitored, and the measurement accuracy can reach ±5με.

[0025] (7) The third shielding layer adopts a silver-plated nylon silk braiding layer as the third shielding layer, the tough nylon base material provides excellent cutting resistance, tear resistance and wear resistance, and serves as an entity barrier against external mechanical damage, and a specific braiding angle is adopted to optimize the flexibility, while providing the last shield against low-frequency radiation interference and electrostatic discharge (ESD) of the external environment, the high resistance characteristic effectively inhibits the formation of ground loop current.

[0026] (8) The outer sheath adopts a continuous corrugated annular structure, so that the longitudinal flexibility and radial compression strength of the cable are greatly improved.

[0027] (9) The recess array is adopted as the micro flow guide groove, the flow guide groove and the mesh gap of the external silver-plated nylon braiding layer jointly form a distributed capillary drainage channel network, once the outer sheath is locally damaged and water enters, the liquid will be first limited in the capillary network and flow along the axial direction, rather than immediately penetrate and erode the internal core layer, and the design realizes the physical water sensitivity sensing. When the water flows to the cable end portion along the flow guide groove, the water can be directly found, or the water can be detected by the humidity sensor arranged at the end portion, so that the water entering early warning can be timely sent, and valuable response time is provided for the maintenance personnel, meanwhile, the flow guide groove structure of the inner wall increases the elastic deformation space inside the outer sheath to a certain extent, further improves the overall flexibility of the cable, and increases the heat dissipation area of the inner surface of the outer sheath, and improves the heat dissipation performance of the cable.

[0028] (10) The preparation method adopts a modular layered manufacturing strategy, the power transmission layer, the control signal layer and the optical fiber communication layer are respectively manufactured first, then overall integration is carried out, and finally the construction of the external intelligent protection and external shielding layer is completed, so that the manufacturing difficulty and risk are greatly reduced, and the product consistency and reliability are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments and in combination with the drawings, in which: Figure 1 It is a structural schematic diagram of the application; Figure 2 It is a structural schematic diagram of the optical fiber group of the application.

[0030] The labels in the attached diagram are: Power transmission layer 1, conductor layer 1-1, conductor insulation 1-2, first shielding layer 1-3; Control signal layer 2, main shielding layer 2-1, sub-shielding layer 2-2, control conductor 2-3, control insulation 2-4; Fiber optic communication layer 3, second shielding layer 3-1, elastic buffer layer 3-2, stainless steel tube 3-3, multiple fiber optic units 3-4, water-blocking grease 3-5; Intelligent protection and external shielding layer 4, high-strength aramid yarn woven layer 4-1, conformal intelligent sensing layer 4-2, isolation layer 4-3, third shielding layer 4-4, outer sheath 4-5, flow guide groove 4-6; Water-blocking strip 5. Detailed Implementation

[0031] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0032] Example 1, such as Figure 1 The intelligent composite cable based on modal isolation shown includes a power transmission layer 1, a control signal layer 2, an optical fiber communication layer 3, and an intelligent protection and external shielding layer 4 arranged sequentially from the inside out. The overall structural design adopts a layered composite structure to ensure the reliability of mechanical performance, and adopts an asymmetric shielding architecture to achieve full-spectrum interference suppression from extremely low frequency to high frequency. It completely solves the signal distortion problem caused by the coexistence of high and low frequency interference in complex industrial environments, and provides the ultimate solution for high-reliability data transmission.

[0033] Specifically, the power transmission layer 1 includes, from the inside out, a conductor layer 1-1, conductor insulation 1-2, and a first shielding layer 1-3 for attenuating low-frequency strong magnetic fields. The conductor layer 1-1 is formed by tightly pressing multiple high-purity oxygen-free copper wires with fan-shaped cross-sections, improving space utilization and flexibility. The conductor insulation 1-2 is a ceramicized silicone rubber insulation layer with a high temperature resistance rating of ≥180℃. The first shielding layer 1-3 uses a high-permeability nanocrystalline alloy strip, such as Fe... 73.5 Si 13.5 B9Nb3Cu1, and formed a continuous magnetic path through longitudinal laser seamless welding process, with an initial relative permeability μi≥80000 (test conditions: frequency 1kHz, AC magnetic field strength ≤0.1A / m), is specifically designed for efficient attenuation of low-frequency strong magnetic field interference.

[0034] The control signal layer 2 includes a main shielding layer 2-1 and multiple control wire cores evenly distributed circumferentially between the main shielding layer 2-1 and the power transmission layer 1. Each control wire core adopts a wire pair structure, including a sub-shielding layer 2-2 and a pair of control conductors 2-3 disposed within the sub-shielding layer 2-2. The control conductors 2-3 are made of multi-strand silver-plated copper wire with a specification of 18~24AWG and a stranding pitch ≤10 times the wire diameter to reduce the skin effect. Each control conductor 2-3 is covered with foamed polyethylene extrusion to form control insulation 2-4, and the dielectric constant of the control insulation 2-4 is ≤1.5 to reduce signal delay. The sub-shielding layer 2-2 is an aluminum-plastic composite film, and the main shielding layer 2-1 is a tin-plated copper wire braided main shielding layer with a coverage of ≥90% for dissipating high-frequency interference current.

[0035] The fiber optic communication layer 3 comprises multiple fiber optic groups evenly arranged circumferentially. The structural design of these fiber optic groups follows a logical sequence of "core transmission → mechanical protection → electromagnetic protection," such as... Figure 2 As shown, the structure includes, from the outside in, a second shielding layer 3-1, an elastic buffer layer 3-2, a stainless steel tube 3-3, and multiple optical fiber units 3-4. Water-blocking grease 3-5 is filled between the optical fiber units 3-4 and the stainless steel tube 3-3 for water blocking, buffering, and chemical protection. The optical fiber units 3-4 use G.657.A2 bend-resistant single-mode optical fiber and are placed side-by-side inside the stainless steel tube 3-3. The corrugated wall of the stainless steel tube 3-3 facilitates the close fit of the outer elastic buffer layer 3-2, preventing mutual rotation and forming a loose-tube core transmission unit that provides a stable and reliable optical signal transmission channel. The stainless steel tube 3-3 provides strong resistance to pressure and lateral impact. The elastic buffer layer 3-2 is a layer of silicone gel elastomer covering the stainless steel tube 3-3. Its soft elastic modulus forms a soft transition zone between the rigid stainless steel tube 3-3 and the outer shielding layer, effectively absorbing and dispersing external vibration and impact energy, preventing direct force transmission to the optical fiber units 3-4. When the cable bends, this layer deforms, providing space for the internal stainless steel tube 3-3 to move, preventing excessive strain on the fiber optic unit 3-4 and effectively solving the "mechanical mismatch" problem. The second shielding layer 3-1 is used for electrical absorption and is a layer of polymer-based composite material with a gradient distribution of carbon nanotubes. Its gradient design achieves a transition from high reflection inside to high absorption outside, effectively suppressing high-frequency electromagnetic interference. As a non-metallic shielding layer, it fundamentally eliminates the grounding loop interference problem caused by metallic shielding layers. At the same time, as the outermost sheath of this functional unit, it provides preliminary physical and environmental protection for the internal elastic buffer layer 3-2 and fiber optic unit 3-4.

[0036] The intelligent protection and external shielding layer 4 consists of a high-strength aramid yarn woven layer 4-1, a conformal intelligent sensing layer 4-2, an isolation layer 4-3, a third shielding layer 4-4, and an outer sheath 4-5, from the inside out, achieving a deep integration of mechanical strength, intelligent sensing, and multiple protections.

[0037] The high-strength aramid yarn braid layer 4-1 is made of aramid yarn produced by Kevlar® or Technora®, with a braid density ≥ 95% and a tensile strength ≥ 3000N, serving as a force-bearing layer to bear most of the axial tension generated during cable operation and installation, ensuring that the internal precision functional core, such as optical fiber and control wire, is in a "zero tension" or low tension state, free from stress damage, while its flexible braid structure provides radial cushioning for the internal core, resisting external impact and compression.

[0038] The conformal intelligent sensing layer 4-2 includes a sensing optical fiber pasted on the outer surface of the high-strength aramid yarn braid layer in a sinusoidal path by coating flexible adhesive, with FBG gratings engraved on the sensing optical fiber, which can sense the temperature distribution on the cable surface in real time, realize overheating warning, and has a temperature measurement accuracy of ±0.5°C. Combined with OTDR technology, it can locate and identify events such as vibration and impact along the length of the cable. At the same time, the "sinusoidal" layout makes it extremely sensitive to axial tension and bending strain, allowing accurate monitoring of cable overload stretching, bending radius, and vibration state, with a measurement accuracy of ±5με. This layer is set inside the third shielding layer 4-4, so the sensing signal is fully protected from external electromagnetic interference and can most directly sense the strain of the aramid force-bearing layer, thus more accurately monitoring the overall tension and bending stress of the cable.

[0039] The isolation layer 4-3 is made of flexible TPU or PE material, which wraps, fixes and protects the conformal intelligent sensing layer 4-2 flatly, isolates it from the third shielding layer 4-4, and prevents short circuiting or wear and tear.

[0040] The third shielding layer 4-4 is a silver-plated nylon braid layer with a braid angle of 55-65°, which provides excellent cut resistance, tear resistance and wear resistance with its tough nylon substrate, serving as a physical barrier against external mechanical damage, and uses a specific braid angle to optimize flexibility, providing the last layer of shielding against low-frequency radiation interference and electrostatic discharge (ESD) from the external environment, while its high resistance effectively suppresses the formation of ground loop current.

[0041] The outer sheath 4-5 is made of thermoplastic polyurethane added with a halogen-free environmentally friendly flame retardant, has a continuous corrugated annular structure, the height difference between the valleys and the peaks of the outer sheath is 0.8-1.2 mm, the corrugated pitch is 10-15 mm, the longitudinal flexibility and the radial compression strength of the cable are greatly improved, and the minimum bending radius is ≤5D. The continuous corrugated annular structure forms an array of grooves extending in the axial direction on the inner wall of the outer sheath 4-5, each groove has a semi-elliptical or trapezoidal cross section, the depth is 0.2-0.3 mm, the width is 0.5-1 mm, and the distance between adjacent grooves is 3-5 mm, so that a micro flow guide groove 4-6 is creatively formed on the inner surface of the outer sheath 4-5. The flow guide groove and the mesh gap of the outer silver-plated nylon braided layer together form a distributed capillary drainage channel network. Once the outer sheath is locally damaged and water enters, the liquid will first be confined in the capillary network and flow in the axial direction, rather than immediately penetrating and eroding the internal core layer horizontally. This design realizes physical water sensitivity. When the water flows along the flow guide groove to the end of the cable, it can be directly observed, or detected by a humidity sensor installed at the end, thereby timely issuing a water entry warning and providing valuable response time for maintenance personnel. In addition, the flow guide groove structure on the inner wall increases the elastic deformation space inside the outer sheath to some extent, further improves the overall flexibility of the cable, and increases the heat dissipation area of the inner surface of the outer sheath, thereby improving the heat dissipation performance of the cable.

[0042] The cable structure of the embodiment innovatively adopts an asymmetric shielding architecture of "nanocrystalline alloy (magnetic shielding), CNT gradient material (electric absorption), and silver-plated nylon (equipotential shielding)", breaks through the limitations of traditional single shielding technology, and realizes deep integration of four functions of power transmission, control signal, optical fiber communication, and intelligent monitoring in a single cable structure; the wiring space is saved by more than 60%, which helps to miniaturize and lightweight the equipment, and realizes full-spectrum interference suppression from extremely low frequency (50Hz power frequency magnetic field, shielding effectiveness >35dB) to high frequency (1MHz-10GHz, shielding effectiveness >65dB).

[0043] The bionic buffer structure of "stainless steel pipe, silicone elastomer, and aramid force bearing layer" perfectly solves the mechanical performance mismatch problem of heterogeneous materials, and the reciprocating bending life exceeds 1 million times under the harsh condition of a diameter bending ratio ≤5D, which is more than 10 times higher than that of a traditional structure, meets the long-term reliability requirements of high-frequency bending and flexing scenes of industrial robots, mobile equipment, and the like, and greatly reduces the maintenance cost.

[0044] The FBG sensing network is precisely embedded in a sine wave path by using an innovative "coating, bonding and isolation layer fixing" process. The sensing system is double protected by the isolation layer and the shielding layer, completely isolating external electromagnetic interference, and the signal signal-to-noise ratio is extremely high. It realizes in-situ monitoring of multiple parameters such as temperature (±0.5℃), strain (±5με), vibration, etc., and the fault response time is shortened by more than 60% compared with the external bonding method. The cable is transformed from a passive transmission component to an intelligent sensing terminal, providing accurate data basis for predictive maintenance.

[0045] The silver-plated nylon braided layer is placed under the outer sheath 4-5 to form an effective "Faraday cage". Any static charge accumulated on the surface of the outer sheath 4-5 can be quickly discharged, realizing true electrostatic discharge (ESD) protection, and providing excellent physical protection capabilities such as anti-cutting and abrasion resistance.

[0046] The base material of the outer sheath 4-5 uses flame-retardant reinforced thermoplastic polyurethane (FR-TPU) and reaches the highest flame-retardant level of UL94 V-0 through halogen-free and environmentally friendly flame retardants, which is safe and reliable, has excellent oil resistance, ultraviolet (UV) resistance and high wear resistance, and is suitable for complex and harsh working environments. The continuous corrugated structure on the outer surface has a very small bending radius (≤5D), making it easy to install and lay in narrow spaces. The micro-flow guide grooves on the inner surface form a distributed network with the braided layer, which can limit the invading water in the grooves and guide it along the axial direction, effectively preventing water from penetrating and corroding the internal core horizontally, realizing physical water-sensitive sensing function, significantly increasing the heat dissipation area of the inner wall of the outer sheath, improving the heat conduction and dissipation path inside the cable, and helping to reduce the operating temperature and improve safety and service life. The coordinated design of the outer corrugation and the inner flow guide groove of the outer sheath 4-5 improves the overall flexibility of the cable, making it have high strength and protection while maintaining flexibility and ease of use.

[0047] When the outer sheath is damaged and water enters, on the one hand, water can be guided to both ends of the cable through the flow guide grooves, and on the other hand, if water penetrates into the core area of the cable, the isolation layer, the water-blocking tape at the concentric cable of the three core components, and the water-blocking paste in the optical fiber layer can all play a role in radial and longitudinal water blocking in time, realizing excellent waterproof function.

[0048] Embodiment 2 provides a method for preparing the modal isolation-based intelligent composite cable of embodiment 1, specifically including the following steps: Step S1: preparing a power transmission layer, a control line core and an optical fiber group respectively; Step S11: preparing the power transmission layer: Conductor stranding: multiple strands of high-purity oxygen-free copper wire are tightly pressed and fan-shaped stranded through a tubular stranding machine to obtain a conductor with high packing density and excellent flexibility.

[0049] Insulation extrusion: after the conductor is twisted, the twisted conductor is extruded by an extruder to form a ceramicized silicone rubber insulation layer, and the insulation layer is cross-linked and cured by passing through a high-temperature vulcanization channel, so as to form an insulation core with high temperature resistance (≥180℃).

[0050] First shielding layer 1-3 forming: using longitudinal wrapping process, tightly wrap high permeability nanocrystalline alloy tape outside the insulation core. Immediately use longitudinal laser welding equipment to perform high-speed and seamless welding on the longitudinal seam of the alloy tape to form a continuous, complete and sealed metal tubular magnetic shielding layer, which completely eliminates magnetic leakage.

[0051] Step S12: control line core preparation: Unit line pair making: twist a plurality of silver-plated copper wires by a regular pitch ≤10 times the wire diameter by a stranding machine to form a differential pair. Extrude foamed polyethylene insulation on the twisted line pair to form a unit line with low dielectric constant (εr≤1.5). Wrap an aluminum-plastic composite film outside each unit line to form a sub-shielding layer 2-2.

[0052] Cabling and overall shielding: twist a plurality of sub-shielded unit line pairs into cables by a cage stranding machine, and increase a filler rope together according to the cable requirements. After cabling, braid a tinned copper wire braid layer (coverage rate ≥90%) outside the assembly as an overall shielding layer 2-1 for discharging high-frequency interference.

[0053] Step S13: preparation of optical fiber group: Place a plurality of G.657.A2 bend-resistant single-mode optical fibers in a stainless steel tube, and inject waterproof ointment to form a core transmission unit. Extrude a layer of silicone gel elastomer outside the stainless steel tube by an extruder to form an elastic buffer layer. Then, extrude a layer of carbon nanotube (CNT) gradient distribution polymer composite material by a second extruder to form a non-metallic electric absorption shielding layer, i.e., a second shielding layer 3-1.

[0054] Step S2: overall cabling, using concentric stranding equipment, twisting the power transmission layer, the control line core and the optical fiber group prepared above in a synchronous manner according to the structure design requirements, and wrapping with a water-blocking tape 5 to form a cable core; adjusting the tension of each unit in real time by an online tension monitoring system to ensure that the twisted structure is compact and round, and the concentricity deviation of each layer is less than ±0.1mm; Step S3: preparation of intelligent protection and external shielding layer; Twist the twisted cable core by a high-speed braiding machine to tightly braid high-strength aramid yarn outside the cable core, and the braiding density is ≥95% to form a high-strength aramid yarn braid layer as a load-bearing layer to bear the main tensile strength. The cable core passes through a programmable eccentric guide roller to guide the sensing optical fiber with the FBG array to make a precise sinusoidal path around the high-strength aramid yarn woven layer, to synchronously and uniformly coat the low-modulus flexible adhesive on the surface of the sensing optical fiber and the high-strength aramid yarn woven layer, to make the adhesive quickly cured through a UV curing furnace, and to firmly "paste" and shape the sensing optical fiber on the surface of the load-bearing layer; The cable core with the completed sensing layer attached passes through another high-speed weaving machine to weave silver-plated nylon wires outside the cable core to form a third shielding layer with electromagnetic shielding and physical protection functions; then a thermoplastic polyurethane material is extruded through an extruder, and a halogen-free environmentally friendly flame retardant is blended into the material through a double-screw blending technology; a corrugated mold corresponding to the structural design of the cable is installed at the outlet of the extruder to form a corrugated outer sheath as the outermost layer.

[0055] The manufacturing method of the embodiment adopts a modular layered manufacturing strategy, i.e., the power transmission layer, the control signal layer and the optical fiber communication layer are respectively manufactured first, then integrated as a whole, and finally the external intelligent protection and external shielding layer is constructed, which greatly reduces the manufacturing difficulty and risk, and guarantees the high consistency and reliability of the product.

[0056] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the present application. It should be understood that the above description is only for specific embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A smart composite cable based on modal isolation, characterized in that: The system comprises, from the inside out, a power transmission layer, a control signal layer, an optical fiber communication layer, and an intelligent protection / external shielding layer. The power transmission layer includes, from the inside out, a conductor layer, conductor insulation, and a first shielding layer for attenuating low-frequency strong magnetic fields. The control signal layer includes a main shielding layer and multiple control cores evenly distributed circumferentially between the main shielding layer and the power transmission layer; each control core has a sub-shielding layer. The optical fiber communication layer includes multiple optical fiber groups evenly distributed circumferentially; each optical fiber group has a second shielding layer for electro-absorption, and this second shielding layer is a non-metallic shielding layer. The intelligent protection / external shielding layer has a third shielding layer for equipotential shielding.

2. The intelligent composite cable based on modal isolation according to claim 1, characterized in that: The conductor layer is formed by pressing together multiple fan-shaped wires. The conductor insulation is a ceramicized silicone rubber insulation layer. The first shielding layer is made of a high-permeability nanocrystalline alloy strip and a continuous magnetic path is formed by longitudinal laser seamless welding process.

3. The intelligent composite cable based on modal isolation according to claim 1, characterized in that: The optical fiber assembly also includes an elastic buffer layer, a stainless steel tube, and multiple optical fiber units sequentially nested within the second shielding layer. The gap between the optical fiber units and the stainless steel tube is filled with water-blocking grease.

4. The intelligent composite cable based on modal isolation according to claim 1, characterized in that: The second shielding layer is a polymer-based composite material layer with a gradient distribution of carbon nanotubes.

5. The intelligent composite cable based on modal isolation according to claim 1, characterized in that: The intelligent protection and external shielding layer also includes an outer sheath wrapped around the third shielding layer and a conformal intelligent sensing layer and a high-strength aramid yarn braided layer arranged sequentially within the third shielding layer. The braiding density of the high-strength aramid yarn braided layer is ≥95%, and the tensile strength is ≥3000N.

6. The intelligent composite cable based on modal isolation according to claim 5, characterized in that: The conformal intelligent sensing layer includes a sensing optical fiber that is coated with flexible adhesive and attached to the outer surface of a high-strength aramid yarn braided layer in a sinusoidal path, and the sensing optical fiber is engraved with an FBG grating.

7. The intelligent composite cable based on modal isolation according to claim 5, characterized in that: The third shielding layer is a silver-plated nylon filament braided layer, and the braiding angle of the silver-plated nylon filament braided layer is 55~65°.

8. The intelligent composite cable based on modal isolation according to claim 7, characterized in that: The outer sheath is made of thermoplastic polyurethane with added halogen-free environmentally friendly flame retardant, and has a continuous corrugated annular structure in cross section.

9. A smart composite cable based on modal isolation according to claim 8, characterized in that: The continuous corrugations of the annular structure form an array of grooves extending axially on the inner wall of the outer sheath. The cross-section of the grooves is semi-elliptical or trapezoidal, with a depth of 0.2~0.3mm, a width of 0.5~1mm, and a spacing of 3~5mm between adjacent grooves.

10. A method for preparing a smart composite cable based on modal isolation, used to prepare the smart composite cable as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step S1: Prepare the power transmission layer, control core, and optical fiber assembly separately; Step S2: Overall cabling. Using a concentric stranding device, according to the structural design requirements, the prepared power transmission layer, the required number of control cores and optical fiber groups are stranded synchronously and wrapped with water-blocking tape to form the cable core. The tension of each unit is adjusted in real time through the online tension monitoring system to ensure that the stranded structure is tight and round, and the concentricity deviation of each layer is less than ±0.1mm. Step S3: Prepare the intelligent protection and external shielding layer; The stranded cable core is tightly braided with high-strength aramid yarn on its outside by a high-speed braiding machine, with a braiding density of ≥95%, forming a high-strength aramid yarn braided layer, which serves as a load-bearing layer to bear the tensile strength. The cable core is guided by a programmable eccentric guide wheel to guide the sensing optical fiber with the FBG array written on it to circle the outside of the high-strength aramid yarn braided layer in a precise sine wave path. Low modulus flexible adhesive is simultaneously and uniformly coated on the surface of the sensing optical fiber and the high-strength aramid yarn braided layer. The adhesive is then cured quickly in a UV curing oven, which firmly "attaches" and shapes the sensing optical fiber on the surface of the load-bearing layer. The cable core, after the sensing layer has been attached, is braided with silver-plated nylon filaments on the outside by another high-speed braiding machine to form a third shielding layer that has both electromagnetic shielding and physical protection functions. Then, thermoplastic polyurethane material is extruded through an extruder and a halogen-free environmentally friendly flame retardant is incorporated using twin-screw blending technology. The outlet of the extruder is equipped with a corrugated mold that matches the structural design of the cable to form the outermost corrugated outer sheath.

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