Coaxial cable for inhibiting high-frequency complex motion shielding fatigue and method for wrapping same

Abstract

The present application relates to the field of radio frequency transmission technology, and more particularly to a coaxial cable for suppressing high-frequency composite motion shielding fatigue and a wrapping forming method thereof, comprising obtaining a voltage standing wave ratio deviation to determine an outer conductor dynamic health degree index; determining a unit cycle health degree change rate based on the outer conductor dynamic health degree index and equivalent fatigue cycle number to locate the running state of the cable corresponding to the current joint; determining an optimal wrapping interval under the current bending working condition, or determining a target tension ratio based on the wrapping parameters of each layer of the bidirectional outer conductor, and adjusting the actual wrapping pitch and the wrapping tension of each layer of the outer conductor in combination with the dominant damage factor; and determining whether to obtain an interlayer contact resistance based on the adjusted unit cycle health degree change rate to determine an interlayer contact state degradation index to determine the interlayer contact condition between the outer conductors. The present application optimizes the wrapping pitch and tension by detecting the joint working condition and combining the cable performance change, thereby suppressing the fatigue cracking of the outer conductor.

Description

Technical Field

[0001] This invention relates to the field of radio frequency transmission technology, and in particular to a coaxial cable for suppressing high-frequency composite motion shielding fatigue and its wrapping and forming method. Background Technology

[0002] With the rapid development of humanoid robots and industrial automation technology, radio frequency (RF) coaxial cables are increasingly used in robot joints, camera modules, millimeter-wave radar, and other components, undertaking key functions such as high-speed signal transmission and antenna feeder connections. However, the shoulder, elbow, wrist, and knee joints of humanoid robots exhibit high-frequency, large-angle composite motion characteristics during operation, specifically characterized by small bending radii (≤8D), high-frequency torsion (±180° or even continuous rotation), simultaneous superposition of bending and torsion, and ultra-long cycle times exceeding 1 million cycles. This special operating condition places far more stringent requirements on the mechanical integrity and electrical performance stability of RF coaxial cables than in traditional application scenarios.

[0003] Currently, humanoid robots require radio frequency coaxial cables to be laid in areas such as the shoulders, elbows, wrists, and knees for camera signal transmission, millimeter-wave communication, high-speed data transmission, and antenna feeder connections. Existing solutions generally use automotive-grade RG-174 cables, which are characterized by single-strand or few-strand stranded copper conductors, single-layer braided shielding, and ordinary PVC or PE sheaths. This structure is mainly designed for the vibration environment of automobiles. However, humanoid robots are used in environments with the following characteristics: 1. small bending radius (≤8D), 2. high-frequency torsion (±180° or even continuous rotation), 3. bending + torsion composite cycles, and 4. long cycle times (>1 million cycles). Under the above conditions, the existing RG-174 structure is prone to: broken center conductor wires, fatigue cracking of outer conductors, impedance drift and insertion loss degradation. Currently, there is no radio frequency coaxial cable structure specifically optimized for the dynamic working conditions of humanoid robots.

[0004] Chinese Patent Publication No. CN121122816A discloses a special cable for complex environments and its manufacturing method. This special cable includes a cable core, a composite protective layer, an armor layer, and an outer sheath. The composite protective layer comprises an inner sheath, a middle reinforcing layer, and an outer sheath. The armor layer is formed by wrapping a metal strip, and its inner side has a continuous raised structure that interlocks with the spiral grooves on the surface of the outer sheath, forming a mechanical interlock to effectively prevent armor layer displacement and loosening. A reinforcing core is embedded in the grooves on the outer side of the metal strip, and the reinforcing core is fixed to the metal strip by spring plates, forming a reinforced buffer, significantly improving fatigue resistance and impact resistance. It is suitable for complex working conditions involving frequent dynamic bending, torsion, and vibration, such as marine cables, towing cables, and robot cables, and has the advantages of stable structure, strong fatigue resistance, and long service life. Therefore, the aforementioned special cable for complex environments and its manufacturing method have the following problems: There is a lack of quantitative assessment of the fatigue degradation rate of the external conductor under high-frequency bending and torsional combined motion conditions of humanoid robot joints, and a lack of directional optimization of wrapping pitch and tension based on the dominant damage factors. Summary of the Invention

[0005] To address this, the present invention provides a coaxial cable for suppressing fatigue during high-frequency composite motion and a wrapping forming method thereof, in order to overcome the lack of quantitative assessment of the fatigue degradation rate of the external conductor under high-frequency bending and torsional composite motion conditions of humanoid robot joints in the prior art, and to achieve directional optimization of wrapping pitch and tension based on the dominant damage factors.

[0006] To achieve the above objectives, the present invention provides a method for forming a coaxial cable wrapping to suppress high-frequency composite motion shielding fatigue, comprising: The motion parameters of the joints through which the cable passes are periodically acquired. The voltage standing wave ratio deviation under the equivalent fatigue cycle number is combined with the unit cyclic impedance degradation rate to determine the dynamic health index of the outer conductor. The motion parameters include the joint bending angle time series, the joint torsion angle time series, and the joint motion angular velocity time series. Based on the external conductor dynamic health index and the equivalent fatigue cycle number, the unit cycle health change rate is determined to locate the operating status of the cable corresponding to the current joint. In response to the operating state of the cable, the bending-dominant period and the torsion-dominant period are divided, and the duration ratio and average motion amplitude of each period are obtained. The damage contribution ratio is determined by combining the average deviation of the standing wave ratio in each period to distinguish the dominant damage factors of the bidirectional outer conductor. Determine the optimal wrapping spacing under the current bending condition, or determine the target tension ratio based on the wrapping parameters of each layer of the bidirectional outer conductor, and adjust the actual wrapping pitch and the wrapping tension of each layer of the outer conductor in combination with the dominant damage factors; Whether to obtain the interlayer contact resistance is determined based on the adjusted unit cycle health change rate, and the interlayer contact status between the outer conductors is determined based on the determined interlayer contact status degradation index. The axial change of the cable outer diameter is obtained to determine the wrapping quality index. Combined with the interlayer contact condition, it is determined whether to correct the second layer wrapping tension based on the interlayer contact condition degradation index or adjust the wrapping pitch based on the wrapping quality index. Based on the motion parameters, the operating condition characteristic parameters are obtained to determine the operating condition severity factor, and the cable withstand capability factor is determined based on the voltage standing wave ratio change, so as to determine the cable matching degree index under operating conditions and judge the matching status of cable withstand capability and operating condition severity. In response to the matching state, a threshold correction factor is determined to correct the rate of change threshold of the unit cycle health change rate.

[0007] Furthermore, the cumulative number of bending cycles and torsion cycles of the joint are accumulated in real time and converted into equivalent fatigue cycles; The external conductor dynamic health index is the product of the unit cyclic impedance degradation rate and the motion mode correction factor, and the motion mode correction factor is determined according to the joint motion angular velocity time sequence. If the rate of change of unit cycle health is less than or equal to the first rate of change threshold, the cable is judged to be in a stable operating state and the current cable wrapping process meets the operating conditions. If the rate of change of unit cycle health is greater than the first rate of change threshold and less than the second rate of change threshold, the cable is judged to be under attention assessment and the cable has a progressive fatigue damage trend. If the rate of change of unit cycle health is greater than or equal to the second rate of change threshold, the cable is judged to be in a warning replacement state, and the damage to the outer conductor of the cable is significant.

[0008] Furthermore, the bending-dominant period is the period when the absolute value of the joint bending angle is greater than the absolute value of the joint torsion angle, and the torsion-dominant period is the period when the absolute value of the joint torsion angle is greater than the absolute value of the joint bending angle. The duration percentage includes the percentage of flexion duration during the flexion-dominant period and the percentage of torsion duration during the torsion-dominant period; the average motion amplitude includes the average joint flexion angle during the flexion-dominant period and the average joint torsion angle during the torsion-dominant period. The mean deviation of the standing wave ratio at each time period includes the mean bending deviation in the bending phase interval and the mean torsional deviation in the torsional phase interval.

[0009] Furthermore, the process of distinguishing the dominant damage factors in bidirectional outer conductors includes, If the damage contribution ratio is greater than the first contribution threshold, then joint bending is determined to be the dominant damage factor. Repeated bending causes the outer conductor's wrapped spiral to bear alternating tensile and compressive stress. If the damage contribution ratio is less than or equal to the first contribution threshold and greater than or equal to the second contribution threshold, it is determined that the joint bending and torsion work together, and the outer conductor is simultaneously subjected to bending and torsional alternating stress under the combined motion. If the damage contribution ratio is less than the second contribution threshold, then joint torsion is determined to be the dominant damage factor, and the torque cancellation efficiency of the double-layer reverse wrapping is insufficient.

[0010] Furthermore, since joint flexion is the dominant injury factor, the actual wrapping distance is adjusted to the optimal wrapping pitch, and the tension of the first and second wrapping layers is adjusted according to the ratio of the optimal wrapping pitch to the actual wrapping pitch. When the joint is bent and twisted together, the torque cancellation efficiency of the double-layer reverse wrapping is insufficient. Based on the target tension ratio, the wrapping tension ratio is changed by adjusting the tension of the second layer of wrapping.

[0011] Furthermore, if the adjusted rate of change of unit cycle health is greater than the first rate of change threshold, the current contact resistance between the first outer conductor and the second outer conductor is obtained to determine the interlayer contact state degradation index. If the interlayer contact degradation index is less than or equal to the first index threshold, then the interlayer contact between the outer conductors is considered to be good. If the interlayer contact degradation index is greater than the first index threshold and less than or equal to the second index threshold, then the interlayer contact between the outer conductors is judged to be slightly degraded. If the interlayer contact degradation index is greater than the second index threshold, then the interlayer contact between the outer conductors is judged to be significantly degraded.

[0012] Furthermore, when the interlayer contact between the outer conductors is slightly degraded, a tension correction based on the contact state is performed, and the tension of the second layer wrapping is increased based on the interlayer contact state degradation index. The cable outer diameter non-uniformity along the axial direction is obtained to define the wrapping quality index. If the wrapping quality index is less than the critical index threshold, it is determined that there is non-uniformity in the wrapping pitch or tension. Pitch correction based on the outer diameter uniformity is performed, and the wrapping pitch is adjusted according to the wrapping quality index.

[0013] Furthermore, the working condition characteristic parameters include the 90th percentile values ​​corresponding to several average angular velocities, several joint bending angles, and several joint torsional angles, denoted as high-frequency motion intensity index, large-angle bending frequency index, and large-angle torsional frequency index. The cable withstand capability factor and the operating condition severity factor are used to determine the cable matching degree index. If the cable matching degree index is greater than or equal to the first matching degree, it is judged that the cable withstand capability is greater than the operating condition severity and the matching is good. If the cable matching degree index under operating conditions is less than the first matching degree but greater than or equal to the second matching degree, the cable is judged to be in a critical matching state, and the change rate threshold is corrected. If the cable matching degree index under operating conditions is less than the second matching degree, it is determined that the cable has insufficient endurance and is not suitable for the current operating conditions.

[0014] Furthermore, when the cable is in a critical matching state, a threshold correction factor is determined to correct the rate of change threshold, the rate of change threshold including a first rate of change threshold and a second rate of change threshold; If the threshold correction factor is greater than one, the actual degradation is judged to be faster than expected; if the threshold correction factor is less than one, the actual degradation is judged to be slower than expected. The expected degradation rate benchmark is determined based on the operating condition severity factor and the cable endurance factor, and the threshold correction factor is determined based on the ratio of the unit cycle health change rate to the expected degradation rate benchmark. If the cable is in a critical matching state and the threshold correction factor is greater than one, it is determined that the cable degradation is accelerated, and the first rate of change threshold and the second rate of change threshold are reduced. If the cable is well matched with the operating conditions and the threshold correction factor is less than one, then the cable performance is judged to be better than expected, and the first rate of change threshold and the second rate of change threshold are increased.

[0015] A coaxial cable for suppressing high-frequency composite motion shielding fatigue, comprising: The radio frequency coaxial cable consists of a center conductor, a dielectric, a first outer conductor, a second outer conductor, an isolation layer, and an outer sheath from the inside out. The center conductor is a composite stranded structure of metal conductor and high-strength fiber. The outer conductor is a double-layer reverse spiral wrapping structure. The outer conductor is the shielding layer of the radio frequency coaxial cable. The shielding layer includes a first spiral wrapping layer and a second spiral wrapping layer, with the two wrapping directions being opposite. The center conductor consists of multiple silver-plated copper alloy wires or silver-plated copper-clad steel wires, and at least one high-strength fiber; the outer conductor consists of bare copper foil wires, silver-plated copper foil wires, and flat copper strips. The high-strength fiber is selected from one or more of aramid fiber, ultra-high molecular weight polyethylene fiber, and liquid crystal polymer fiber; The fiber arrangement methods include being located at the center of the conductor as a tensile core, being twisted together with the metal conductor, or having multiple fibers evenly distributed in the stranded structure.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the composite stranded structure of the metal conductor and high-strength fiber in the center conductor of the coaxial cable can reduce stress concentration in the metal conductor, suppress plastic deformation during bending, improve tensile strength, increase cyclic bending life, and reduce the probability of wire breakage. Unlike the prior art that only increases the number of copper wires to improve flexibility, the present invention introduces non-metallic high-strength fibers to bear part of the mechanical load, realizing a mechanical load-sharing mechanism. The double-layer reverse spiral wrapping structure of the outer conductor of the present invention can improve the cable's resistance to torsional fatigue, reduce cracking of the outer conductor, maintain the integrity of the outer conductor, and improve the stability of the outer conductor. The key point is that the double-layer reverse wrapping forms a torque balance structure during torsion, rather than simply superimposing the outer conductor.

[0017] Furthermore, the robot deploys radio frequency coaxial cables at joints such as the shoulder, elbow, wrist, and knee. This invention establishes a dynamic health index to quantify the fatigue degradation rate of the outer conductor by real-time monitoring of joint motion parameters and cable VSWR response. Based on the damage contribution ratio, it identifies the dominant factors of bending or torsion to optimize the wrapping pitch and tension in a directional manner. After adjustment, it introduces two-dimensional detection of interlayer contact resistance and outer diameter uniformity for depth compensation. At the same time, it adaptively corrects the judgment threshold based on the matching degree between the severity of the working conditions and the cable's endurance, forming a closed-loop control system of "monitoring-diagnosis-optimization-feedback". This effectively suppresses fatigue cracking of the outer conductor, extends the service life of the cable under the combined motion conditions of the robot joints, maintains stable electrical performance under long-term bending, torsion, and combined cyclic motion conditions, and suppresses high-cycle combined motion shielding fatigue.

[0018] Furthermore, this invention establishes a quantitative index and its rate of change criterion for health metrics reflecting the dynamic degradation of the outer conductor by real-time monitoring of robot joint motion parameters and cable VSWR response. This enables accurate online assessment of the cable's fatigue state under bending-torsion combined conditions. The invention unifies the conversion of joint bending and torsion cycles into equivalent fatigue cycle numbers and introduces a torsional equivalence coefficient determined by the material's shear modulus, tensile modulus, and wrapping pitch, thus closely linking the degradation rate calculation with the cable's structural characteristics and actual motion loads. Based on a threshold criterion for the rate of change of health per unit cycle, it provides timely warnings during the progressive damage stage, preventing signal transmission failure caused by fatigue cracking of the outer conductor. This provides a quantitative basis for the condition maintenance and process optimization of radio frequency cables for humanoid robot joints.

[0019] Furthermore, when the cable is in a progressive fatigue damage trend, this invention separates the bending-dominant and torsional-dominant periods of the joint, extracts the duration ratio, average motion amplitude, and average standing wave ratio deviation of each period, and constructs a damage contribution ratio index to quantitatively distinguish the relative contribution of bending and torsional damage. After locating the dominant damage factor based on the damage contribution ratio, for bending-dominant damage, the optimal wrapping pitch is accurately solved by calculating the ratio of the actual bending strain of the outer conductor edge to the allowable strain of the material, and the double-layer tension is adjusted accordingly. For torsional-dominant damage, the target tension ratio is calculated based on the mechanical relationship between the double-layer pitch and the helix angle to optimize the torque cancellation efficiency. For combined bending and torsional damage, a composite adjustment of pitch and tension is performed. This achieves a closed-loop linkage between damage pattern recognition and process parameter directional optimization, effectively suppressing fatigue cracking of the outer conductor and extending the service life of the cable under the combined motion conditions of robot joints.

[0020] Furthermore, if the degradation rate still fails to meet the standard after initial optimization of process parameters, this invention calculates the interlayer contact degradation index by measuring the contact resistance between the two outer conductors and comparing it with the factory baseline value, thus quantitatively assessing the degree of interlayer contact degradation. Simultaneously, a wrapping quality index is defined based on the axial non-uniformity of the cable's outer diameter to identify non-uniformity in the wrapping pitch or tension. For slight contact degradation, the tension of the second wrapping layer is increased proportionally to the degradation index to enhance interlayer adhesion. For insufficient wrapping uniformity, the wrapping pitch is fine-tuned according to the quality index deviation. Through dual-dimensional detection of electrical contact parameters and geometric dimensional parameters, in-depth diagnosis and precise compensation for hidden defects in the wrapping process are achieved, further suppressing the fatigue degradation rate of the outer conductor and improving the long-term operational reliability of the cable under complex working conditions of robot joints.

[0021] Furthermore, this invention extracts the 90th percentile values ​​of angular velocity, bending angle, and torsional angle from the cable's entire lifecycle operation data as operating condition characteristic parameters, constructs an operating condition severity factor to quantify the joint motion load level, and defines a cable tolerance factor by combining static standing wave ratio degradation and interlayer contact degradation index, thereby establishing an operating condition-cable matching index to achieve a comprehensive assessment of cable adaptability. When the cable is in a critical matching state, a threshold correction factor is determined based on the ratio of the actual degradation rate to the expected degradation rate, adaptively adjusting the first and second rate of change thresholds, and introducing a matching correction term to constrain the adjustment range. This allows the health criterion threshold to dynamically adjust with the actual operating condition severity and the cable's own degradation state, avoiding misjudgments or omissions caused by fixed thresholds, and improving the accuracy of condition assessment and the adaptability of process optimization. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the coaxial cable structure in an embodiment of the present invention; Figure 2 This is a schematic flowchart of a coaxial cable for suppressing high-frequency composite motion shielding fatigue and its wrapping forming method in an embodiment of the present invention. Figure 3 This is a flowchart illustrating the process of locating the operating state of the cable corresponding to the current joint in an embodiment of the present invention. Figure 4 This is a flowchart illustrating the process of differentiating the dominant damage factors of a bidirectional outer conductor in an embodiment of the present invention. In the diagram: 1-Center conductor, 2-Dielectric, 31-First outer conductor, 32-Second outer conductor, 4-Insulation layer, 5-Outer sheath. Detailed Implementation

[0023] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0024] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0025] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0026] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] Please see Figures 1-4 As shown, Figure 1 This is a schematic diagram of the coaxial cable structure in an embodiment of the present invention; Figure 2 This is a schematic flowchart of a coaxial cable for suppressing high-frequency composite motion shielding fatigue and its wrapping forming method in an embodiment of the present invention. Figure 3 This is a flowchart illustrating the process of locating the operating state of the cable corresponding to the current joint in an embodiment of the present invention. Figure 4 This is a flowchart illustrating the process of distinguishing the dominant damage factors of a bidirectional outer conductor in an embodiment of the present invention.

[0028] This invention provides a coaxial cable for suppressing high-frequency composite motion shielding fatigue and a wrapping forming method thereof, comprising: Step S1: Periodically acquire the motion parameters of the joints through which the cable passes, and determine the unit cyclic impedance degradation rate by combining the voltage standing wave ratio deviation under the equivalent fatigue cycle number to determine the dynamic health index of the outer conductor. The motion parameters include the joint bending angle time sequence, the joint torsion angle time sequence, and the joint motion angular velocity time sequence. Step S2: Based on the dynamic health index of the outer conductor and the equivalent fatigue cycle number, determine the rate of change of health per unit cycle to locate the operating status of the cable corresponding to the current joint. Step S3: In response to the operating state of the cable, divide the bending-dominant period and the torsion-dominant period to obtain the duration ratio and average motion amplitude of each period. Combine the average deviation of the standing wave ratio deviation in each period to determine the damage contribution ratio and distinguish the dominant damage factors of the bidirectional outer conductor. Step S4: Determine the optimal wrapping spacing under the current bending condition, or determine the target tension ratio based on the wrapping parameters of each layer of the bidirectional outer conductor, and adjust the actual wrapping pitch and the wrapping tension of each layer of the outer conductor in combination with the dominant damage factors. Step S5: Determine whether to obtain the interlayer contact resistance based on the adjusted unit cycle health change rate, so as to determine the interlayer contact state degradation index and judge the interlayer contact status between the outer conductors. Step S6: Obtain the axial change of the cable outer diameter to determine the wrapping quality index, and combine it with the interlayer contact condition to determine whether to correct the second layer wrapping tension based on the interlayer contact condition degradation index or adjust the wrapping pitch based on the wrapping quality index. Step S7: Based on the motion parameters, obtain the working condition characteristic parameters to determine the working condition severity factor, and based on the voltage standing wave ratio change, determine the cable withstand capability factor, so as to determine the working condition cable matching index and judge the matching status of cable withstand capability and working condition severity. Step S8: In response to the matching state, determine a threshold correction factor to correct the rate of change threshold of the unit cycle health change rate.

[0029] Specifically, the robot deploys radio frequency coaxial cables at joints such as the shoulder, elbow, wrist, and knee. This invention establishes a dynamic health index to quantify the fatigue degradation rate of the outer conductor by real-time monitoring of joint motion parameters and cable standing wave ratio response. Based on the damage contribution ratio, it identifies the dominant factors of bending or torsion to optimize the wrapping pitch and tension in a directional manner. After adjustment, it introduces two-dimensional detection of interlayer contact resistance and outer diameter uniformity for depth compensation. At the same time, it adaptively corrects the judgment threshold based on the matching degree between the severity of the working conditions and the cable's endurance, forming a closed-loop control system of "monitoring-diagnosis-optimization-feedback". This effectively suppresses fatigue cracking of the outer conductor, extends the service life of the cable under the complex motion conditions of the robot joints, maintains stable electrical performance under long-term bending, torsion, and complex cyclic motion conditions, and suppresses shielding fatigue of high-cycle complex motion.

[0030] In this embodiment, the radio frequency coaxial cable consists of a center conductor 1, a dielectric 2, a first outer conductor 31, a second outer conductor 32, an isolation layer 4, and an outer sheath 5 from the inside out. The center conductor is a composite stranded structure of metal conductor and high-strength fiber, and the outer conductor is a double-layer reverse spiral wrapping structure. The material used is a metal fiber composite material with high-performance fiber life. The double-layer outer conductor is the shielding layer of the radio frequency coaxial cable.

[0031] Specifically, the central conductor is a composite reinforced central conductor structure, which includes multiple silver-plated copper alloy wires or silver-plated copper-clad steel wires, and at least one high-strength fiber; The high-strength fiber is selected from one or more of aramid fiber, ultra-high molecular weight polyethylene fiber, and liquid crystal polymer fiber; The fiber arrangement methods include being located at the center of the conductor as a tensile core, being twisted together with the metal conductor, or having multiple fibers evenly distributed in the stranded structure.

[0032] In this embodiment, the center conductor material is 19 strands of silver-plated copper alloy with a size of 0.52 mm and a tolerance of ±0.03; the dielectric material is PFA with a size of 1.62 mm and a tolerance of ±0.08; the outer conductor is copper foil wire, with the first outer conductor having a size of 1.78 mm and a tolerance of ±0.08, and the second outer conductor having a size of 1.94 mm and a tolerance of ±0.10; the insulating layer material is PTFE with a size of 2.20 mm and a tolerance of ±0.10; and the outer sheath material is black PUR with a size of 2.80 mm and a tolerance of ±0.20.

[0033] Specifically, the composite stranded structure of the metal conductor and high-strength fiber in the center conductor can reduce stress concentration in the metal conductor, suppress plastic deformation during bending, improve tensile strength, increase cyclic bending life, and reduce the probability of wire breakage. Unlike the existing technology that only increases the number of copper wires to improve flexibility, this invention introduces non-metallic high-strength fibers to bear part of the mechanical load, thus realizing a mechanical load-sharing mechanism.

[0034] Specifically, the outer conductor has a double-layer reverse spiral wrapping structure, which includes a first spiral wrapping layer and a second spiral wrapping layer, with the two wrapping directions being opposite.

[0035] The pitch of the skew-wrapped conductor is 10 to 15 times the outer diameter. The tension of the two outer conductors must be balanced to avoid stress and to counteract torsional stress.

[0036] The outer conductor material includes bare copper foil wire, silver-plated copper foil wire, and flat copper strip. Compared with the traditional braided outer conductor, the traditional braided structure has intersections, which are fatigue sources and prone to torsion and opening. The structure of the present invention has no intersections, and the stress is continuously distributed in opposite directions to cancel the torque. In practice, the dielectric is a solid extruded layer, and the material is selected from FEP, PFA or XLPE. The dielectric thickness is controlled to maintain a characteristic impedance of 50Ω or 75Ω.

[0037] The outer sheath material is selected from polyurethane (TPU), TPEE or oil-resistant elastomer, and has high wear resistance, tear resistance and oil resistance.

[0038] Specifically, the double-layer reverse spiral wrapping structure of the outer conductor of the present invention can improve the cable's resistance to torsional fatigue, reduce outer conductor cracking, maintain the integrity of the outer conductor, and improve the stability of the outer conductor. The key point is that the double-layer reverse wrapping forms a torque balance structure when torsion, rather than simply superimposing the outer conductor.

[0039] During the actual operation of the robot joint, real-time monitoring is carried out through sensors built into the joint and sensing devices arranged along the cable. The motion parameters of the joints through which the cable passes are periodically and in real time obtained by the robot joint encoder, including the joint bending angle timing φb(t) (°), the joint torsion angle timing φt(t) (°), and the joint motion angular velocity timing ω(t) (° / s). The change in the standing wave ratio (VSWR) of the cable signal is used to indirectly monitor the condition of the outer conductor. The VSWR deviation ΔVSWR(t) is determined based on the VSWR time series value VSWR(t). VSWR deviation = VSWR time series value - initial VSWR. It is understandable that the initial voltage standing wave ratio (VSWR) is the VSWR measured under standard static test conditions when the cable is manufactured, in a brand new and unused state; the VSWR time series value is the sequence data of the VSWR changing over time obtained by periodic sampling during the actual operation of the cable.

[0040] Based on zero-crossing detection of joint angle signals, the cumulative number of bending cycles and torsional cycles is accumulated in real time. The cumulative number of bending cycles and the cumulative number of torsion cycles are converted into the equivalent fatigue cycle number. The equivalent fatigue cycle number = cumulative number of bending cycles + torsional fatigue equivalent coefficient × cumulative number of torsion cycles. In the formula, the torsional fatigue equivalence coefficient is determined by the cable structure. The torsional fatigue equivalence coefficient = 1 + (outer conductor material shear modulus × cable outer diameter) / (outer conductor material tensile modulus × average wrapping pitch) × (maximum torsion angle under working conditions / maximum bending angle under working conditions). The torsional fatigue equivalence coefficient is a semi-empirical dimensionless parameter, in which the shear modulus / tensile modulus of the outer conductor material characterizes the ratio of the material's shear and tensile modulus, the cable outer diameter / average wrapping pitch characterizes the ratio of the cable's radial dimension to the characteristic length of the wrapping structure, and the maximum torsion angle / maximum bending angle under operating conditions characterizes the load mode under operating conditions. The product of these three factors constitutes the equivalent conversion factor of torsional damage relative to bending damage.

[0041] In practice, the maximum torsion angle under the working condition is the maximum value of the joint torsion angle sequence, and the maximum bending angle under the working condition is the maximum value of the joint bending angle sequence; the copper alloy shear modulus is 44 GPa, and the copper alloy tensile modulus is 110 GPa; the average wrapping pitch is the arithmetic mean of the first layer wrapping pitch and the second layer wrapping pitch in the cable outer conductor wrapping process.

[0042] The unit cyclic impedance degradation rate is defined as the average change in VSWR relative to the initial value within each equivalent cycle, with the unit being "per cycle". The unit cyclic impedance degradation rate = (VSWR deviation after equivalent fatigue cycles / initial voltage VSWR) / equivalent fatigue cycle number. The physical meaning of the unit cyclic impedance degradation rate is the rate of impedance stability degradation caused by changes in the outer conductor structure within each equivalent cyclic period.

[0043] The dynamic health index of the outer conductor is determined based on the unit cyclic impedance degradation rate, wherein the dynamic health index of the outer conductor = unit cyclic impedance degradation rate × motion mode correction factor. The motion mode correction factor is 1 + k × (ωavg / ωref), where k is the velocity influence coefficient, which is taken as 0.1~0.2 in practice, ωavg is the average motion angular velocity of the joint within the current monitoring window, which is exemplarily taken as 30° / s~120° / s, and ωref is the reference angular velocity, which is taken as 60° / s in practice.

[0044] A stable external conductor dynamic health index near its initial value indicates that the external conductor is in a healthy state. A continuous increase in the external conductor dynamic health index indicates that the external conductor has entered a progressive damage stage. An accelerated increase in the external conductor dynamic health index indicates that damage accumulation is accelerating and the risk of fatigue cracking is increasing. The monitoring window is set to calculate the actual dynamic health index of the external conductor every 5000 equivalent cycles, obtain the recorded initial dynamic health index, and determine that the health increment = actual dynamic health index - initial dynamic health index, and the health change rate per unit cycle = health increment / corresponding equivalent fatigue cycle number. If the rate of change of unit cycle health is less than or equal to the first rate of change threshold, the cable is judged to be in a stable operating state and the current cable wrapping process meets the operating conditions. If the rate of change of unit cycle health is greater than the first rate of change threshold but less than the second rate of change threshold, the cable is judged to be in a state of attention assessment, and the cable has a progressive fatigue damage trend. If the rate of change of unit cycle health is greater than or equal to the second rate of change threshold, the cable is judged to be in a warning replacement state, and the cumulative damage to the outer conductor of the cable is significant. Wherein, the first rate of change threshold is 1×10 -6 cycle-2 The second rate of change threshold is 5 × 10 -6 cycle -2 .

[0045] Specifically, this invention establishes a quantitative index and its rate of change criterion for health metrics reflecting the dynamic degradation of the outer conductor by real-time monitoring of robot joint motion parameters and cable VSWR response. This enables accurate online assessment of the cable's fatigue state under bending-torsion combined conditions. The invention unifies the conversion of joint bending and torsion cycles into equivalent fatigue cycle numbers and introduces a torsional equivalence coefficient determined by the material's shear modulus, tensile modulus, and wrapping pitch, closely linking the degradation rate calculation with the cable's structural characteristics and actual motion loads. Based on a threshold criterion for the rate of change of health per unit cycle, it provides timely warnings during progressive damage stages, preventing signal transmission failure caused by fatigue cracking of the outer conductor. This provides a quantitative basis for the condition maintenance and process optimization of radio frequency cables for humanoid robot joints.

[0046] When a cable is under close monitoring and evaluation and shows a tendency for progressive fatigue damage, the main driving factors of the damage should be identified in order to determine the direction of optimization of process parameters.

[0047] Determine the flexion-dominant period and the torsion-dominant period. The flexion-dominant period is the moment when the absolute value of the joint flexion angle is greater than the absolute value of the joint torsion angle, and the torsion-dominant period is the moment when the absolute value of the joint torsion angle is greater than the absolute value of the joint flexion angle. The duration percentage and average motion amplitude of the flexion-dominant and torsion-dominant periods are obtained respectively, including the flexion duration percentage of the flexion-dominant period and the torsion duration percentage of the torsion-dominant period, as well as the average joint flexion angle and the average joint torsion angle during the flexion-dominant and torsion-dominant periods. Align the standing wave ratio deviation with the joint motion phase, determine the average bending deviation of the standing wave ratio deviation in the bending phase interval, and determine the average torsional deviation of the standing wave ratio deviation in the torsional phase interval, wherein the bending phase interval is the phase segment of the bending-dominant period, and the torsional phase interval is the phase segment of the torsional-dominant period.

[0048] It is understandable that when a cable is in a bending-dominated motion state, the outer conductor mainly bears the bending alternating stress, indicating that bending deformation is the main cause of impedance mismatch. The larger the average bending deviation, the more obvious the damage to the cable caused by bending, and vice versa.

[0049] The injury contribution ratio is determined based on the mean deviation, the duration of the deviation, and the average amplitude of motion. The injury contribution ratio is calculated as follows: (mean bending deviation × percentage of bending duration × average joint bending angle) / (mean torsion deviation × percentage of torsion duration × average joint torsion angle). If the damage contribution ratio is greater than the first contribution threshold, then joint bending is determined to be the dominant damage factor. Repeated bending causes the outer conductor's wrapped spiral to bear alternating tensile and compressive stress. If the damage contribution ratio is less than or equal to the first contribution threshold and greater than or equal to the second contribution threshold, it is determined that the joint bending and torsion work together, and the outer conductor is simultaneously subjected to bending and torsional alternating stress under the combined motion. If the damage contribution ratio is less than the second contribution threshold, then joint torsion is determined to be the dominant damage factor, and the torque cancellation efficiency of the double-layer reverse wrapping is insufficient. In practice, the first contribution threshold is 1.5 and the second contribution threshold is 0.67.

[0050] Joint flexion is the dominant injury factor. The actual wrapping distance is adjusted to the optimal wrapping pitch, and the tension of the first and second wrapping layers is adjusted according to the ratio of the optimal wrapping pitch to the actual wrapping pitch.

[0051] Adjust the actual wrapping pitch to the optimal wrapping pitch, where the optimal wrapping pitch = 2π × outer conductor mid-diameter radius / .

[0052] Specifically, the radius of the outer conductor is the distance from the center line of the outer conductor cross-section to the cable axis. The allowable strain of the outer conductor material is the maximum elastic strain that the outer conductor material can withstand under fatigue life requirements. The unit is dimensionless and can be determined according to the material supplier's datasheet or through fatigue test calibration. For copper alloy outer conductor materials, the strain is taken as 0.15%~0.25% under high-cycle fatigue conditions. When this strain value is exceeded, the material will enter the low-cycle fatigue region, and the life will be significantly shortened. The actual strain under bending conditions is the maximum tensile strain borne by the outer edge of the outer conductor of the cable at the minimum bending radius. The actual strain under bending conditions = outer conductor outer diameter / (2 × minimum bending radius). When a cable is bent, the outer conductor is stretched and the inner conductor is compressed. The actual strain under bending conditions represents the tensile strain of the outermost fiber. The typical value of actual strain under bending conditions in practice ranges from 0.3% to 0.8%, where the outer diameter of the outer conductor is the diameter of the outermost surface of the outer conductor, and the minimum bending radius is the minimum bending radius experienced by the cable during the joint movement of the robot, that is, the radius of curvature at the position where the cable bends most severely.

[0053] When the joint is bent and twisted together, the torque cancellation efficiency of the double-layer reverse wrapping is insufficient. The wrapping tension ratio is adjusted to the target tension ratio, which is the tension ratio of the second layer to the first layer required to achieve complete torque cancellation of the double-layer outer conductor. The second layer wrapping tension is adjusted to be the product of the first layer wrapping tension and the target tension ratio. The target tension ratio is calculated as P2 × sin(2α2) / P1 × sin(2α1), where P1 and P2 are the first and second layer wrapping pitches, and α1 and α2 are the first and second layer wrapping helix angles. The pitch, a process setting value, determines the inclination angle of the wrapping helix, thus affecting the mechanical response of the outer conductor to torsion. The helix angle determines the magnitude of the circumferential stress component generated by the outer conductor during torsion. sin(2α) is the characteristic function of the torsional stiffness of a helical structure in mechanics of materials.

[0054] When the outer conductor is subjected to bending and torsional alternating stress under combined motion, the wrapping pitch and wrapping tension are adjusted in combination. The actual wrapping pitch is reduced to 0.95 times, and the first layer wrapping tension and the second layer wrapping tension are increased to 1.05 times.

[0055] Specifically, when a cable is experiencing progressive fatigue damage, this invention separates the bending-dominant and torsional-dominant periods, extracts the duration percentage, average motion amplitude, and average standing wave ratio deviation of each period, and constructs a damage contribution ratio index to quantitatively distinguish the relative contributions of bending and torsional damage. After locating the dominant damage factor based on the damage contribution ratio, for bending-dominant damage, the optimal wrapping pitch is accurately calculated by determining the ratio of the actual bending strain at the outer edge of the outer conductor to the allowable strain of the material, and the double-layer tension is adjusted accordingly. For torsional-dominant damage, the target tension ratio is calculated based on the mechanical relationship between the double-layer pitch and the helix angle to optimize torque cancellation efficiency. For combined bending and torsional damage, a composite adjustment of pitch and tension is performed. This achieves a closed-loop linkage between damage pattern recognition and directional optimization of process parameters, effectively suppressing fatigue cracking of the outer conductor and extending the service life of the cable under combined robot joint motion conditions.

[0056] If the adjusted unit cycle health change rate is still greater than the first change rate threshold, then DC resistance measurement is performed on the outer conductors at both ends of the cable to measure the current contact resistance between the first layer of shielding and the second layer of shielding. The current contact resistance is compared with the factory reference value of the contact resistance between the first layer of outer conductor and the second layer of outer conductor, and the interlayer contact state degradation index is calculated as (current contact resistance - factory reference value of contact resistance) / factory reference value of contact resistance. If the interlayer contact degradation index is less than or equal to the first index threshold, then the interlayer contact between the outer conductors is considered to be good. If the interlayer contact degradation index is greater than the first index threshold and less than or equal to the second index threshold, then the interlayer contact between the outer conductors is judged to be slightly degraded. If the interlayer contact degradation index is greater than the second index threshold, then the interlayer contact between the outer conductors is judged to be significantly degraded.

[0057] Specifically, when the interlayer contact between the outer conductors is slightly degraded, tension correction based on the contact state is performed, and the tension of the second layer wrapping is increased to improve the interlayer contact. The adjusted second layer wrapping tension = the current second layer wrapping tension × (1 + 0.1 × interlayer contact state degradation index).

[0058] Define the wrapping quality index as 1 - outer diameter non-uniformity. Measure the change in cable outer diameter along the axial direction to obtain the maximum outer diameter, minimum outer diameter, and average outer diameter. The outer diameter non-uniformity is defined as (maximum outer diameter - minimum outer diameter) / average outer diameter. If the wrapping quality index is less than the critical index threshold, it is determined that there is non-uniformity in the wrapping pitch or tension. Pitch correction based on the outer diameter uniformity is performed. The wrapping pitch is adjusted according to the wrapping quality index to improve the wrapping uniformity. The adjusted wrapping pitch = current wrapping pitch × (1 + 0.02 × (1 - wrapping quality index)). Wherein, the first index threshold is 0.1, the second index threshold is 0.3, and the critical index threshold is 0.95.

[0059] Specifically, if the degradation rate still fails to meet the standard after initial optimization of process parameters, this invention calculates the interlayer contact degradation index by measuring the contact resistance between the two outer conductors and comparing it with the factory baseline value, thus quantitatively assessing the degree of interlayer contact degradation. Simultaneously, it defines a wrapping quality index based on the axial non-uniformity of the cable's outer diameter to identify non-uniformity in wrapping pitch or tension. For slight contact degradation, the tension of the second wrapping layer is increased proportionally to the degradation index to enhance interlayer adhesion. For insufficient wrapping uniformity, the wrapping pitch is fine-tuned according to the quality index deviation. Through dual-dimensional detection of electrical contact parameters and geometric dimensional parameters, this invention achieves in-depth diagnosis and precise compensation for hidden defects in the wrapping process, further suppressing the fatigue degradation rate of the outer conductor and improving the long-term operational reliability of the cable under complex working conditions of robot joints.

[0060] The average angular velocity, joint bending angle and joint torsion angle of several detection cycles in the current cable's full life cycle operation parameter data are obtained to determine the working condition characteristic parameters. The working condition characteristic parameters include the 90th percentile values ​​corresponding to the average angular velocity, joint bending angle and joint torsion angle, which are denoted as high-frequency motion intensity index, large-angle bending frequency index and large-angle torsion frequency index. The operating condition severity factor is determined based on the aforementioned operating condition characteristic parameters to evaluate the cable's adaptability to the current joint motion operating conditions. Operating condition severity factor = (high-frequency motion intensity index / reference angular velocity) × (large angle bending frequency index / reference bending angle) × (large angle torsion frequency index / reference torsion angle); In practice, the reference angular velocity is 60° / s, the reference bending angle is 90°, and the reference torsional angle is 90°.

[0061] The severity factor comprehensively reflects the frequency and amplitude of joint movement. A severity factor >1 indicates that the severity of the working condition is higher than the baseline working condition.

[0062] Perform shutdown status detection, measure the current voltage standing wave ratio (VSWR) of the cable in a static state, calculate the static degradation amount based on the initial factory value of the VSWR, static degradation amount = current VSWR - initial factory value of VSWR, and measure the current interlayer contact resistance; Define the cable withstand capability factor as 1 / (1 + static degradation amount / voltage standing wave ratio initial value) × 1 / (1 + interlayer contact condition degradation index). It is understood that the first term of the cable withstand capability factor reflects the degree of static degradation of electrical performance, and the second term reflects the degree of contact degradation of mechanical structure. A cable withstand capability factor of 1 indicates that the cable is in brand new and healthy condition, while a cable withstand capability factor of <1 indicates that the cable has undergone irreversible degradation and its withstand capability has decreased.

[0063] The cable compatibility index is determined based on the cable withstand capability factor and the operating condition severity factor. The cable compatibility index = cable withstand capability factor / operating condition severity factor. If the cable matching degree index under operating conditions is greater than or equal to the first matching degree, then the cable's withstand capability is greater than the severity of the operating conditions, and the matching is good. If the cable matching degree index under operating conditions is less than the first matching degree but greater than or equal to the second matching degree, the cable is judged to be in a critical matching state, and the change rate threshold is corrected. If the cable matching degree index under the working condition is less than the second matching degree, it is determined that the cable has insufficient endurance and is not suitable for the current working condition. In practice, the first matching degree is 1.0 and the second matching degree is 0.7.

[0064] When the cable is in a critical matching state, a threshold correction factor is determined to correct the rate of change threshold, which includes a first rate of change threshold and a second rate of change threshold. Specifically, if the threshold correction factor is greater than one, it is determined that the actual degradation is faster than expected, and the threshold should be lowered; if the threshold correction factor is less than one, it is determined that the actual degradation is slower than expected, and the threshold can be relaxed.

[0065] In this embodiment, if the cable is in a critical matching state and the threshold correction factor is greater than one, it is determined that the cable degradation is accelerating, and the first rate of change threshold and the second rate of change threshold are reduced.

[0066] Specifically, the corrected first rate of change threshold = the current first rate of change threshold × (1 / threshold correction factor) × matching degree correction term; The corrected second rate of change threshold = the current second rate of change threshold × (1 / threshold correction factor) × matching degree correction term; If the cable is well matched with the operating conditions and the threshold correction factor is less than one, then the cable performance is judged to be better than expected, and the first rate of change threshold and the second rate of change threshold are increased.

[0067] Specifically, the increased first rate of change threshold = min(corrected first rate of change threshold, 2.0 × 10⁻⁶) -6 The increased second rate of change threshold = min(corrected second rate of change threshold, 8.0 × 10⁻⁶) -6 ).

[0068] In practice, the lower limit of the first rate of change threshold is 0.5 × 10⁻⁶. -6 cycle -2 The upper limit is 2.0×10 -6 cycle -2 The lower limit of the second rate of change threshold is 3.0 × 10⁻⁶. -6 cycle -2 The upper limit is 8.0×10 -6 cycle -2 .

[0069] Wherein, the matching degree correction term = min(1.5, max(0.7, 1 / working condition cable matching degree index)), and the threshold correction factor = current unit cycle health change rate / expected degradation rate benchmark. In practice, the degradation rate of cables of the same specification under reference operating conditions is the factory-calibrated value. The expected degradation rate reference represents the theoretically expected degradation rate under the current operating conditions and current cable health status.

[0070] The expected degradation rate benchmark = degradation rate of the same specification cable under benchmark operating conditions × operating condition severity factor α × (1 / Cable endurance factor) β ; In the formula, α is the operating condition influence index, which is taken as 0.5~0.8 in practice, and β is the degradation acceleration index, which is taken as 1.0~1.5 in practice.

[0071] Specifically, this invention extracts the 90th percentile values ​​of angular velocity, bending angle, and torsional angle from the cable's full life-cycle operation data as operating condition characteristic parameters. It constructs an operating condition severity factor to quantify the joint motion load level and defines a cable tolerance factor by combining static standing wave ratio degradation and interlayer contact degradation index. This establishes an operating condition-cable matching index, achieving a comprehensive assessment of the cable's adaptability. When the cable is in a critical matching state, a threshold correction factor is determined based on the ratio of the actual degradation rate to the expected degradation rate. The first and second rate of change thresholds are adaptively increased or decreased, and a matching correction term is introduced to constrain the adjustment range. This allows the health criterion threshold to dynamically adjust with the actual operating condition severity and the cable's own degradation state, avoiding misjudgments or omissions caused by fixed thresholds, and improving the accuracy of condition assessment and the adaptability of process optimization.

[0072] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for forming a coaxial cable wrapping to suppress fatigue caused by high-frequency composite motion shielding, characterized in that, include: The motion parameters of the joints through which the cable passes are periodically acquired. The voltage standing wave ratio deviation under the equivalent fatigue cycle number is combined with the unit cyclic impedance degradation rate to determine the dynamic health index of the outer conductor. The motion parameters include the joint bending angle time series, the joint torsion angle time series, and the joint motion angular velocity time series. Based on the external conductor dynamic health index and the equivalent fatigue cycle number, the unit cycle health change rate is determined to locate the operating status of the cable corresponding to the current joint. In response to the operating state of the cable, the bending-dominant period and the torsion-dominant period are divided, and the duration ratio and average motion amplitude of each period are obtained. The damage contribution ratio is determined by combining the average deviation of the standing wave ratio in each period to distinguish the dominant damage factors of the bidirectional outer conductor. Determine the optimal wrapping spacing under the current bending condition, or determine the target tension ratio based on the wrapping parameters of each layer of the bidirectional outer conductor, and adjust the actual wrapping pitch and the wrapping tension of each layer of the outer conductor in combination with the dominant damage factors; Whether to obtain the interlayer contact resistance is determined based on the adjusted unit cycle health change rate, and the interlayer contact status between the outer conductors is determined based on the determined interlayer contact status degradation index. The axial change of the cable outer diameter is obtained to determine the wrapping quality index. Combined with the interlayer contact condition, it is determined whether to correct the second layer wrapping tension based on the interlayer contact condition degradation index or adjust the wrapping pitch based on the wrapping quality index. Based on the motion parameters, the operating condition characteristic parameters are obtained to determine the operating condition severity factor, and the cable withstand capability factor is determined based on the voltage standing wave ratio change, so as to determine the cable matching degree index under operating conditions and judge the matching status of cable withstand capability and operating condition severity. In response to the matching state, a threshold correction factor is determined to correct the rate of change threshold of the unit cycle health change rate.

2. The coaxial cable wrapping and forming method for suppressing high-frequency composite motion shielding fatigue according to claim 1, characterized in that, The cumulative number of bending cycles and torsion cycles of the joint are accumulated in real time and converted into equivalent fatigue cycles. The external conductor dynamic health index is the product of the unit cyclic impedance degradation rate and the motion mode correction factor, and the motion mode correction factor is determined according to the joint motion angular velocity time sequence. If the rate of change of unit cycle health is less than or equal to the first rate of change threshold, the cable is judged to be in a stable operating state and the current cable wrapping process meets the operating conditions. If the rate of change of unit cycle health is greater than the first rate of change threshold and less than the second rate of change threshold, the cable is judged to be under attention assessment and the cable has a progressive fatigue damage trend. If the rate of change of unit cycle health is greater than or equal to the second rate of change threshold, the cable is judged to be in a warning replacement state, and the damage to the outer conductor of the cable is significant.

3. The method for forming a coaxial cable wrapping to suppress high-frequency composite motion shielding fatigue according to claim 2, characterized in that, The flexion-dominant period is the period when the absolute value of the joint flexion angle is greater than the absolute value of the joint torsion angle, and the torsion-dominant period is the period when the absolute value of the joint torsion angle is greater than the absolute value of the joint flexion angle. The duration percentage includes the percentage of flexion duration during the flexion-dominant period and the percentage of torsion duration during the torsion-dominant period; the average motion amplitude includes the average joint flexion angle during the flexion-dominant period and the average joint torsion angle during the torsion-dominant period. The mean deviation of the standing wave ratio at each time period includes the mean bending deviation in the bending phase interval and the mean torsional deviation in the torsional phase interval.

4. The method for forming a coaxial cable wrapping to suppress high-frequency composite motion shielding fatigue according to claim 3, characterized in that, The process of differentiating the dominant damage factors in a bidirectional external conductor includes, If the damage contribution ratio is greater than the first contribution threshold, then joint bending is determined to be the dominant damage factor. Repeated bending causes the outer conductor's wrapped spiral to bear alternating tensile and compressive stress. If the damage contribution ratio is less than or equal to the first contribution threshold and greater than or equal to the second contribution threshold, it is determined that the joint bending and torsion work together, and the outer conductor is simultaneously subjected to bending and torsional alternating stress under the combined motion. If the damage contribution ratio is less than the second contribution threshold, then joint torsion is determined to be the dominant damage factor, and the torque cancellation efficiency of the double-layer reverse wrapping is insufficient.

5. The coaxial cable wrapping and forming method for suppressing high-frequency composite motion shielding fatigue according to claim 4, characterized in that, Joint flexion is the dominant injury factor. The actual wrapping distance is adjusted to the optimal wrapping pitch, and the tension of the first and second wrapping layers is adjusted according to the ratio of the optimal wrapping pitch to the actual wrapping pitch. When the joint is bent and twisted together, the torque cancellation efficiency of the double-layer reverse wrapping is insufficient. Based on the target tension ratio, the wrapping tension ratio is changed by adjusting the tension of the second layer of wrapping.

6. The method for forming a coaxial cable wrapping to suppress high-frequency composite motion shielding fatigue according to claim 5, characterized in that, If the adjusted unit cycle health change rate is greater than the first change rate threshold, the current contact resistance between the first outer conductor and the second outer conductor is obtained to determine the interlayer contact state degradation index. If the interlayer contact degradation index is less than or equal to the first index threshold, then the interlayer contact between the outer conductors is considered to be good. If the interlayer contact degradation index is greater than the first index threshold and less than or equal to the second index threshold, then the interlayer contact between the outer conductors is judged to be slightly degraded. If the interlayer contact degradation index is greater than the second index threshold, then the interlayer contact between the outer conductors is judged to be significantly degraded.

7. The method for wrapping and forming a coaxial cable to suppress high-frequency composite motion shielding fatigue according to claim 6, characterized in that, When the interlayer contact between the outer conductors is slightly degraded, tension correction based on the contact state is performed, and the second layer wrapping tension is increased based on the interlayer contact state degradation index. The cable outer diameter non-uniformity along the axial direction is obtained to define the wrapping quality index. If the wrapping quality index is less than the critical index threshold, it is determined that there is non-uniformity in the wrapping pitch or tension. Pitch correction based on the outer diameter uniformity is performed, and the wrapping pitch is adjusted according to the wrapping quality index.

8. The method for forming a coaxial cable wrapping to suppress high-frequency composite motion shielding fatigue according to claim 7, characterized in that, The working condition characteristic parameters include the 90th percentile values ​​corresponding to several average angular velocities, several joint bending angles, and several joint torsional angles, denoted as high-frequency motion intensity index, large-angle bending frequency index, and large-angle torsional frequency index. The cable withstand capability factor and the operating condition severity factor are used to determine the cable matching degree index. If the cable matching degree index is greater than or equal to the first matching degree, it is judged that the cable withstand capability is greater than the operating condition severity and the matching is good. If the cable matching degree index under operating conditions is less than the first matching degree but greater than or equal to the second matching degree, the cable is judged to be in a critical matching state, and the change rate threshold is corrected. If the cable matching degree index under operating conditions is less than the second matching degree, it is determined that the cable has insufficient endurance and is not suitable for the current operating conditions.

9. The method for wrapping and forming a coaxial cable to suppress high-frequency composite motion shielding fatigue according to claim 8, characterized in that, When the cable is in a critical matching state, a threshold correction factor is determined to correct the rate of change threshold, which includes a first rate of change threshold and a second rate of change threshold. If the threshold correction factor is greater than one, it is determined that the actual degradation is faster than expected; If the threshold correction factor is less than one, it is determined that the actual degradation is slower than expected; The expected degradation rate benchmark is determined based on the operating condition severity factor and the cable endurance factor, and the threshold correction factor is determined based on the ratio of the unit cycle health change rate to the expected degradation rate benchmark. If the cable is in a critical matching state and the threshold correction factor is greater than one, it is determined that the cable degradation is accelerated, and the first rate of change threshold and the second rate of change threshold are reduced. If the cable is well matched with the operating conditions and the threshold correction factor is less than one, then the cable performance is judged to be better than expected, and the first rate of change threshold and the second rate of change threshold are increased.

10. A coaxial cable prepared using the coaxial cable wrapping and forming method for suppressing high-frequency composite motion shielding fatigue as described in any one of claims 1-9, characterized in that, include: The radio frequency coaxial cable consists of a center conductor, a dielectric, a first outer conductor, a second outer conductor, an isolation layer, and an outer sheath from the inside out. The center conductor is a composite stranded structure of metal conductor and high-strength fiber. The outer conductor is a double-layer reverse spiral wrapping structure. The outer conductor is the shielding layer of the radio frequency coaxial cable. The shielding layer includes a first spiral wrapping layer and a second spiral wrapping layer, with the two wrapping directions being opposite. The center conductor consists of multiple silver-plated copper alloy wires or silver-plated copper-clad steel wires, and at least one high-strength fiber; the outer conductor consists of bare copper foil wires, silver-plated copper foil wires, and flat copper strips. The high-strength fiber is selected from one or more of aramid fiber, ultra-high molecular weight polyethylene fiber, and liquid crystal polymer fiber; The fiber arrangement methods include being located at the center of the conductor as a tensile core, being twisted together with the metal conductor, or having multiple fibers evenly distributed in the stranded structure.

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