Cable life prediction method based on working condition movement

Abstract

The invention relates to the technical field of electric signal data processing, in particular to a cable life prediction method based on working condition movement. The method comprises the following steps of: sleeving a leakage flux ring on the periphery of a cable shielding layer, wherein a Hall array is arranged in the leakage flux ring; an acoustic emission patch is attached to the surface of the shielding layer; a mechanical trigger is arranged at the joint of the cable drag chain; when the mechanical trigger detects a complete bending stroke every time, the Hall array and the acoustic emission patch are started synchronously, and a magnetic flux leakage pulse amplitude value and an ultrasonic elastic wave energy value of the current stroke number are generated; dividing the magnetic flux leakage pulse amplitude value of the same stroke number by the ultrasonic elastic wave energy value to obtain a broken wire coefficient of the stroke number; and accumulating the broken wire coefficients of the continuous stroke numbers of the cable to form a theoretical accumulated broken wire index. According to the invention, through the magnetic flux leakage and acoustic emission monitoring technology and in combination with the accelerated bending test, accurate quantification and life prediction of the broken wire state of the cable are realized, and finally, the reliability of the whole life cycle management of the cable is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical signal data processing, and in particular to a cable life prediction method based on working condition motion. BACKGROUND

[0002] The technical features of cable life under working condition motion mainly reflect the performance and attenuation law of the cable under complex conditions such as dynamic load, mechanical stress, and environmental change. Specifically, during actual operation, the cable will be subjected to repeated mechanical stress such as bending, stretching, and twisting, and may also be subjected to harsh environmental conditions such as high temperature and high humidity. These factors together cause the performance of the cable's insulation layer and conductor to gradually decline, ultimately affecting its service life.

[0003] The traditional method lacks real-time quantitative monitoring capability for the broken wire state of the cable under dynamic working conditions, resulting in inaccurate broken wire state evaluation; the existing cable life prediction technology has errors due to subjective judgment and lacks a scientific failure threshold as a basis; and the existing data processing is complex, making it difficult to efficiently integrate multiple monitoring data and quickly convert it into an intuitive prediction result of the cable life, thereby increasing management costs and failing to provide strong support for stable operation of the equipment. SUMMARY

[0004] Therefore, it is necessary to provide a cable life prediction method based on working condition motion to solve at least one of the above technical problems.

[0005] To achieve the above-mentioned purpose, a cable life prediction method based on working condition motion, the method comprising the following steps:

[0006] Step S1: a magnetic leakage ring is sleeved on the outer periphery of the cable shielding layer, and a Hall array is built-in the magnetic leakage ring; an acoustic emission patch is attached to the surface of the shielding layer; a mechanical trigger is installed at the cable chain joint;

[0007] Step S2: when the mechanical trigger detects a complete bending stroke each time, the Hall array and the acoustic emission patch are started synchronously to generate a magnetic leakage pulse amplitude value and an ultrasonic elastic wave energy value of the current stroke number;

[0008] Step S3: the magnetic leakage pulse amplitude value and the ultrasonic elastic wave energy value of the same stroke number are divided to obtain a broken wire coefficient of the stroke number; the broken wire coefficients of the continuous stroke numbers of the cable are accumulated to form a theoretical cumulative broken wire index;

[0009] Step S4: on an accelerated bending test equipment, an accelerated bending test is performed on the same type of cable until the cable fails, and the theoretical cumulative broken wire index at the time of failure is recorded as a failure threshold;

[0010] Step S5: monitoring and obtaining the real-time cumulative wire breakage index, performing proportional operation on the real-time cumulative wire breakage index and the failure threshold, and outputting the cable remaining life prediction value.

[0011] The beneficial effects of the present application are:

[0012] By sleeving the magnetic flux leakage ring outside the shielding layer and embedding the Hall array, and by attaching the acoustic emission patch on the surface of the shielding layer, and by installing the mechanical trigger at the joint of the cable chain, the precise quantitative monitoring of the wire breakage state of the cable during actual working motion is realized. When the mechanical trigger detects a complete bending stroke, the Hall array and the acoustic emission patch are started synchronously, and the magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value of the current stroke number can be accurately obtained, and then the wire breakage coefficient of the stroke number is calculated. This monitoring method can reflect the wire breakage in the dynamic use process of the cable in real time, avoiding the problem of inaccurate wire breakage state evaluation caused by lack of dynamic monitoring in traditional methods, and providing a reliable basis for the maintenance and replacement of the cable.

[0013] The same type of cable is tested on the accelerated bending test equipment until the cable function fails, and the theoretical cumulative wire breakage index at the time of failure is recorded as the failure threshold, ensuring the reliability of the failure threshold. In actual application, by monitoring and obtaining the real-time cumulative wire breakage index, and performing proportional operation on the real-time cumulative wire breakage index and the failure threshold, the remaining life prediction value of the cable can be accurately output. This life prediction method based on the failure threshold avoids the prediction error caused by subjective judgment, provides scientific decision support for the whole life cycle management of the cable, and effectively reduces the safety risk caused by cable failure.

[0014] The magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value of the same stroke number are divided to obtain the wire breakage coefficient, and the wire breakage coefficients of the continuous stroke numbers of the cable are accumulated to form the theoretical cumulative wire breakage index. This data processing method can efficiently integrate various monitoring data into an index with clear physical meaning. In actual application scenarios, whether it is a cable chain on an industrial automation production line or a flexible cable at the joint of a robot, monitoring data can be quickly processed and converted into an intuitive prediction result of the cable life. This efficient data processing and application method improves the efficiency of cable life management, reduces the increase in management cost caused by complex data processing, and provides a strong guarantee for the stable operation of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 It is a step flowchart of a cable life prediction method based on working condition motion;

[0016] Fig. 2 It is a cable remaining life prediction curve diagram;

[0017] Fig. 3 To accelerate the bending test equipment diagram;

[0018] The object, the function characteristics and the advantages of the present application will be further explained with reference to the embodiments, with reference to the drawings. DETAILED DESCRIPTION

[0019] The technical method of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0020] In addition, the drawings are only schematic illustrations of the present application, and are not necessarily drawn to scale. The same reference signs in the drawings represent the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities, which do not necessarily have to correspond to physically or logically independent entities. The functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0021] It should be understood that although the terms "first", "second" and the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the example embodiments. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] To achieve the above object, please refer to Figs. 1 to 3 A cable life prediction method based on working condition motion, the method comprising the following steps:

[0023] Preferably, step S1: a magnetic leakage ring is sleeved outside the periphery of the cable shielding layer, and a Hall array is built-in the magnetic leakage ring; an acoustic emission patch is attached to the surface of the shielding layer; a mechanical trigger is installed at the joint of the cable chain;

[0024] In an embodiment, when the cable to be tested enters the installation station, first manually or by a mechanical arm to slide the magnetic flux leakage ring along the axial direction to the outer periphery of the shielding layer; the magnetic flux leakage ring is selected to be an open type magnetic ring with a gap of not more than 1mm between the inner diameter and the outer diameter of the cable, 6 radial through holes are uniformly arranged on the circumference of the ring body, one linear Hall element is inserted into each hole, the Hall sensitive surface faces the shielding layer, the leads are led out along the tangential direction of the ring body and are collected to the connector; and at the outer surface of the shielding layer, 50mm away from the two ends of the magnetic flux leakage ring, two rectangular acoustic emission patches are respectively attached using cyanoacrylate adhesive, the patch is 10mm x 5mm x 0.3mm in length x width x thickness, and an insulating film is further covered on the surface to prevent mechanical scratching.

[0025] In another embodiment, the cable chain is placed on the workbench, and the number of joints of the cable chain is not less than 5. On the hinge center line of each joint, an on-off micro mechanical trigger is fixed using an M2 stainless steel screw, the trigger roller is in contact with the inner side of the cable chain, the trigger stroke is 0.5mm, and the reset force is not greater than 0.2N. All trigger signal lines are collected to the end interface along the wire slot on the outer side of the cable chain.

[0026] Preferably, step S2: when the mechanical trigger detects a complete bending stroke each time, the Hall array and the acoustic emission patch are started synchronously to generate the magnetic flux pulse amplitude value and the ultrasonic elastic wave energy value of the current stroke number;

[0027] Optionally, the mechanical trigger includes a first position sensor and a second position sensor respectively arranged at the two end positions of the cable movement track, and step S2 includes the following when the mechanical trigger detects a complete bending stroke each time:

[0028] When the first position sensor detects that the cable reaches the first limit bending position for the first time, a timer is started and marked as the starting point of the stroke;

[0029] The cable continues to move to the second limit bending position, and when the second position sensor detects that the cable reaches the position, it is recorded as the middle point of the stroke;

[0030] The cable returns from the second limit bending position, and when the first position sensor detects that the cable reaches the first limit bending position again, the timer is stopped and marked as the end point of the stroke.

[0031] In this embodiment, the first position sensor and the second position sensor are arranged at the limit positions of the two ends of the cable chain, both of which are roller limit switches, the same type, the contact rated current is 5A, and the effective stroke of the roller is 0.5mm. The first position sensor is installed on the fixed end side plate when the cable chain is fully retracted, and the roller is in rolling contact with the front end baffle of the cable chain; the second position sensor is installed on the moving end side plate when the cable chain is fully extended, and the roller is in rolling contact with the tail end baffle of the cable chain. The center lines of the two sensors are collinear and parallel to the movement axis of the cable chain, and the installation tolerance is ≤±0.5mm.

[0032] In an implementation of the embodiment, when the cable moves to the first position sensor trigger position, the sensor contact is closed, the timer is started and marked as the starting point of the stroke; the cable continues to move to the second position sensor trigger position, the contact is closed and recorded as the middle point of the stroke; the cable reverses and when the first position sensor is triggered again, the timer stops and is marked as the end point of the stroke. The sensor signal is connected to the control unit through the shielded cable and the cable slot outside the cable tray, and the time collection of a complete bending stroke is completed.

[0033] Optionally, the step S2 further includes the following when the mechanical trigger detects a complete bending stroke each time:

[0034] Defining the movement process of the cable in the time interval recorded by the timer as a complete bending stroke, and taking the time interval recorded by the timer as the cycle parameter of the complete bending stroke;

[0035] When the first position sensor and the second position sensor complete the corresponding detection actions and the timer completes a complete timing cycle, it is determined that a complete bending stroke is detected.

[0036] In the embodiment of the application, in order to accurately record the complete bending stroke of the cable in the cable tray and obtain the cycle parameter thereof, the following operation process is adopted:

[0037] When the cable moves to the first position sensor trigger point at the starting end along with the cable tray, the timer starts timing immediately, and the starting time of the stroke is recorded at this time; the cable continues to move along the cable tray path until it reaches the second position sensor trigger point at the end, and the middle time of the stroke is marked at this time; then the cable reverses and returns to the starting end and triggers the first position sensor again, and the timer stops timing, and the time interval of the complete process is defined as the cycle parameter of a complete bending stroke.

[0038] Only when the first position sensor and the second position sensor accurately complete their respective detection actions and the timer successfully completes a complete timing cycle, the system will determine that a complete cable bending stroke is successfully detected, thereby ensuring the accuracy and integrity of the stroke recording.

[0039] Optionally, the step S2 includes the following when the Hall array and the acoustic emission patch are simultaneously started to generate the magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value of the current stroke number:

[0040] When the mechanical trigger detects a complete bending stroke and outputs a stroke trigger signal, the rising edge of the stroke trigger signal is taken as the starting point, and the starting instruction is simultaneously sent to the Hall array and the acoustic emission patch;

[0041] After receiving the start instruction, the Hall array collects a set of magnetic flux leakage signals near each of the two extreme bending positions of the stroke, and each set of signals contains continuous pulse waveforms.

[0042] The pulse amplitude sum of each set of signals is calculated, and the sum of the two sets is added as the magnetic flux leakage pulse amplitude value of the current stroke number.

[0043] After receiving the start instruction, the acoustic emission patch continuously collects ultrasonic elastic wave signals throughout the stroke, and monitors the energy value of the ultrasonic elastic wave signals in real time. When the energy value exceeds the preset energy value threshold, an effective pulse is recorded.

[0044] The total number of effective pulses in the stroke is counted and the total energy of all effective pulses is calculated, and the total energy is taken as the ultrasonic elastic wave energy value of the current stroke number.

[0045] In the implementation mode of the present embodiment, when the mechanical trigger detects a complete bending stroke and outputs a stroke trigger signal, the system sends start instructions to the Hall array and the acoustic emission patch synchronously based on the rising edge of the trigger signal.

[0046] In one operation step of the present embodiment, after receiving the start instruction, the Hall array collects a set of magnetic flux leakage signals near each of the two extreme bending positions of the stroke. The collection of magnetic flux leakage signals is completed by a plurality of high-sensitivity Hall elements, which are distributed in an array form within the magnetic flux leakage ring and cover the outer periphery of the cable shielding layer. At each extreme bending position, the Hall array continuously collects a set of magnetic flux leakage signals, and each set of signals contains a plurality of continuous pulse waveforms.

[0047] It should be noted that the calculation method of the magnetic flux leakage pulse amplitude value is as follows: the amplitude sum of all pulses in each set of signals is calculated, i.e. the amplitude values of each pulse are added to obtain the sum of each set of signals. The sum of the two sets of signals is added to obtain the magnetic flux leakage pulse amplitude value of the current stroke number.

[0048] In another operation step of the present embodiment, after receiving the start instruction, the acoustic emission patch starts to continuously collect ultrasonic elastic wave signals throughout the stroke. During the collection process, the system monitors the energy value of the ultrasonic elastic wave signals in real time. When the energy value of the signal exceeds the preset energy value threshold, the system records an effective pulse.

[0049] It should be noted that the ultrasonic elastic wave energy value is obtained as follows: the total number of effective pulses in the stroke is counted, and the total energy of all effective pulses is calculated. Finally, the total energy is taken as the ultrasonic elastic wave energy value of the current stroke number.

[0050] Preferably, step S3: dividing the magnetic flux leakage pulse amplitude value of the same stroke number by the ultrasonic elastic wave energy value to obtain the broken wire coefficient of the stroke number; accumulating the broken wire coefficients of consecutive stroke numbers of the cable to form a theoretical cumulative broken wire index;

[0051] In one operating procedure of this embodiment, for each trip number, the system divides the collected magnetic flux leakage pulse amplitude value by the ultrasonic elastic wave energy value to obtain the wire breakage coefficient for that trip number. Specifically, the magnetic flux leakage pulse amplitude value and ultrasonic elastic wave energy value corresponding to the current trip number are read from a data storage unit, and then a division operation is performed. The result is the wire breakage coefficient for that trip number. For example, if the current trip number is 1, its magnetic flux leakage pulse amplitude value is 100, and its ultrasonic elastic wave energy value is 50, then the wire breakage coefficient is 2.

[0052] In another operation step of this embodiment, the wire breakage coefficients of consecutive cable runs are accumulated. Specifically, starting with run number 1, the wire breakage coefficients for each run number are read one by one and added together. For example, if the wire breakage coefficient for run number 1 is 2, the wire breakage coefficient for run number 2 is 1.5, and the wire breakage coefficient for run number 3 is 1.8, then the theoretical cumulative wire breakage index is 2 + 1.5 + 1.8 = 5.3. The accumulated result is stored as the theoretical cumulative wire breakage index and used in subsequent cable life prediction analysis.

[0053] Preferably, step S4: performing an accelerated bending test on the same type of cables on an accelerated bending test device until the cables fail, and recording the theoretical cumulative broken wire index at the time of failure as the failure threshold;

[0054] Optionally, performing the accelerated bending test on cables of the same model in step S4 includes:

[0055] Cut a cable sample from the middle of the same roll of cable and mark the starting point of the shield braiding direction before cutting;

[0056] Measure the shielding layer thickness and insulation layer thickness of each cable sample, and filter out cable samples whose measurement value fluctuation range is within the preset range.

[0057] In this embodiment, cable samples are cut from the middle section of the same roll of cable. Before cutting, the starting point of the braiding direction is marked on the shielding layer with a marking pen to facilitate subsequent identification of the directionality of the cable. Several cable samples with a length of 1 meter are cut to ensure that the sample quantity meets the test requirements.

[0058] In one implementation of this embodiment, a high-precision micrometer or thickness gauge is used to measure the shielding and insulation thicknesses of each cable sample. Measurements are taken at three different locations on the cable sample, and the average values ​​are taken as the shielding and insulation thicknesses for that sample.

[0059] For example, for a certain cable sample, the measured values of the shielding layer thickness at three positions are 0.5 mm, 0.52 mm and 0.48 mm, and the average value 0.5 mm is taken as the shielding layer thickness of the sample; the measured values of the insulation layer thickness at three positions are 1.2 mm, 1.22 mm and 1.18 mm, and the average value 1.2 mm is taken as the insulation layer thickness of the sample.

[0060] In another implementation of the embodiment, according to the preset thickness fluctuation range, the cable sample whose measured value fluctuation range is within the preset range is screened out. The preset range is usually set according to the production standard and test requirement of the cable. For example, the fluctuation range of the preset shielding layer thickness is ±0.05 mm, and the fluctuation range of the preset insulation layer thickness is ±0.1 mm.

[0061] For the above measurement results, if the shielding layer thickness of a certain cable sample is 0.5 mm and the insulation layer thickness is 1.2 mm, and both values are within the preset range, the sample is selected for subsequent accelerated bending test. If the shielding layer thickness of a certain cable sample is 0.6 mm, which exceeds the preset range, the sample is excluded.

[0062] Optionally, the accelerated bending test equipment includes a fixed base and a movable swing arm, the fixed base is provided with a base mark, and the movable swing arm is provided with a connection part. The cable sample installation operation before the accelerated bending test in step S4 is specifically as follows:

[0063] One end of the cable sample is fixed to the fixed base of the equipment, and when fixing, the cable sample is rotated to align the inclination direction of the shielding layer braid texture with the base mark line;

[0064] The other end is connected to the movable swing arm of the equipment, the connection part is installed with a positioning ring, the inner ring of the positioning ring is tightly fitted with the sample insulation layer, and the outer ring is gap-fitted with the clamping groove of the swing arm;

[0065] The distance between the fixed base and the movable swing arm is adjusted so that there is no stretching wrinkle in the shielding layer and no tension mark on the surface of the insulation layer when the cable sample naturally droops.

[0066] In one operation step of the embodiment, one end of the cable sample is inserted into the clamp of the fixed base. The inner diameter of the clamp should match the outer diameter of the cable to ensure that the cable can be firmly clamped. Before fixing the cable, carefully observe the braid texture of the cable shielding layer, find the direction of the texture inclination, and select a reference point in that direction. Then, rotate the cable sample so that the reference point aligns with the mark line on the fixed base, ensuring that the cable maintains the correct directionality in subsequent tests. The clamping force of the clamp should be moderate, which can fix the cable without damaging the cable.

[0067] In another operation step of the embodiment, the other end of the cable sample is connected to the movable swing arm. A positioning ring is installed at the connection site, the inner ring diameter of the positioning ring should be slightly larger than the outer diameter of the cable insulation layer to ensure close contact with the insulation layer, but not to cause extrusion. The outer ring of the positioning ring cooperates with the clamping groove of the swing arm to form a clearance fit. This fit allows the cable to move freely during the swing arm movement, while maintaining the stability of the connection. When installing the positioning ring, ensure that the clearance fit with the swing arm clamping groove is uniform to avoid affecting the movement of the cable due to improper fit.

[0068] In another operation step of the embodiment, the distance between the fixed base and the movable swing arm is adjusted. The distance is gradually adjusted through the adjustment device on the device until the cable sample is in a natural drooping state, the shielding layer has no stretching wrinkles, and the insulation layer surface has no tension marks. This step requires careful observation of the state of the cable sample to ensure that it is in a natural state during testing to avoid test errors caused by tension or wrinkles. After adjustment, record the distance value at this time to maintain consistent conditions in subsequent tests.

[0069] Optionally, the determination of the cable function failure in step S4 is specifically:

[0070] In the accelerated bending test, after completing each bending cycle, the shielding layer edge is lightly probed with a probe to identify whether there are new broken wires that are raised;

[0071] The insulation layer is detected by light transmission. A light source is placed on one side of the cable sample, and a light screen is used to receive on the other side. The number and shape of the light spots appearing on the light screen are recorded;

[0072] When the number of raised broken wires of the shielding layer exceeds the preset number of broken wires, or when irregular light spots with a number exceeding the preset number of light spots appear on the light screen, the accelerated bending test of the cable sample is terminated.

[0073] In an embodiment, after completing each bending cycle, the edge of the shielding layer of the cable sample is lightly probed with a probe. The probe should be made of a small and soft material to avoid damaging the cable. During operation, the probe is gently probed along the weaving texture direction of the shielding layer, and whether new broken wires are raised is observed. If broken wires are found to be raised, their positions and numbers are recorded.

[0074] In another embodiment, a light source is placed on one side of the cable sample. The light source should be selected to be uniform and have moderate intensity, such as an LED lamp. The other side is placed with a light screen, which should be flat and clean to clearly receive light. After turning on the light source, the number and shape of the light spots appearing on the light screen are observed. The number and shape of the light spots can reflect the integrity of the insulation layer. If the insulation layer is damaged or aged, the number of light spots will increase and the shape will be irregular.

[0075] It is to be noted that during the test, the number of broken wires of the shielding layer and the shape of the light spots on the light screen are continuously monitored. If the number of broken wires of the shielding layer exceeds the preset number of broken wires, or if the shape of the light spots on the light screen is irregular and the number of the light spots exceeds the preset number of light spots, the accelerated bending test of the cable sample is immediately terminated.

[0076] Optionally, the theoretical cumulative broken wire index at the time of failure recorded in step S4 comprises:

[0077] After the cable sample is terminated, the shielding layer is disassembled and the broken wires are combed, the broken wires are classified and counted according to the length, and the classification result of the broken wires is obtained;

[0078] The insulation layer is peeled off, the straight-line distance between the starting point and the clamping point of the crack is measured, and the extension direction of each crack is recorded to obtain the crack measurement data;

[0079] The theoretical cumulative broken wire index is determined according to the classification and counting result of the broken wires and the crack measurement data;

[0080] The theoretical cumulative broken wire indexes of all samples are sorted, and the value located in the middle position in the sorting sequence is taken as the failure threshold.

[0081] In an embodiment, after the cable sample is terminated, the shielding layer of the cable is disassembled using a tool. During disassembly, the conductors inside the shielding layer are not damaged. After disassembly is completed, the shielding layer is laid flat on the workbench. A small probe is used to gently comb the braided wires of the shielding layer, and the positions and numbers of the broken wires are identified and recorded. The broken wires are classified according to the length, for example, the broken wires are divided into three categories: shorter than 1 mm, 1 mm to 5 mm, and longer than 5 mm, and are counted respectively. The final classification and counting result is the classification result of the broken wires.

[0082] In another embodiment, the insulation layer of the cable sample is peeled off to avoid additional damage to the insulation layer. After peeling off is completed, the crack condition on the surface of the insulation layer is observed. The straight-line distance between the starting point and the clamping point of each crack is measured using a ruler or a vernier caliper, and the extension direction of each crack is recorded. For example, the angle of the crack extending outward from the clamping point can be measured using a protractor, and is recorded as the extension direction of the crack.

[0083] In another embodiment, the theoretical cumulative broken wire index is calculated according to the classification and counting result of the broken wires and the crack measurement data. Specifically, the number of each category in the classification and counting result of the broken wires is multiplied by the corresponding weight coefficient; for example, the weight of the broken wire shorter than 1 mm is 1, the weight of the broken wire between 1 mm and 5 mm is 2, and the weight of the broken wire longer than 5 mm is 3, and the results are added. At the same time, according to the length and number of the cracks, the corresponding weight values are assigned, and these values are added to the weight values of the broken wires to obtain the final theoretical cumulative broken wire index.

[0084] In another embodiment, the theoretical cumulative wire breakage indicators of all samples are sorted, for example, if there are 10 samples, the theoretical cumulative wire breakage indicators of the 10 samples are arranged in ascending order. The value at the middle position in the sorted sequence is taken as the failure threshold. If the number of samples is even, the average of the two middle values is taken as the failure threshold. For example, if there are 10 samples, the values at the 5th and 6th positions after sorting are X and Y respectively, and the failure threshold is (X+Y) / 2.

[0085] Preferably, step S5: monitoring and obtaining the real-time cumulative wire breakage indicator, performing proportional operation on the real-time cumulative wire breakage indicator and the failure threshold, and outputting the cable remaining life prediction value.

[0086] Optionally, step S5 includes the following steps:

[0087] Step S51: updating the magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value corresponding to each complete bending stroke in the database;

[0088] Step S52: dividing the updated magnetic flux leakage pulse amplitude value by the ultrasonic elastic wave energy value to obtain a wire breakage update coefficient, and accumulating the wire breakage update coefficient with the wire breakage coefficients of the continuous stroke numbers of the cable to update the theoretical cumulative wire breakage indicator;

[0089] Step S53: storing the updated theoretical cumulative wire breakage indicator as the real-time cumulative wire breakage indicator, and associating the corresponding stroke number and time stamp.

[0090] In one operation step of the present embodiment, the magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value corresponding to each complete bending stroke are updated in the database after the end of the stroke. Specifically, the magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value of the current stroke are obtained from the data acquisition module. These values are stored in the database together with the corresponding stroke number and time stamp. The record format in the database can be: {stroke number, time stamp, magnetic flux leakage pulse amplitude value, ultrasonic elastic wave energy value}.

[0091] In another operation step of the present embodiment, the updated magnetic flux leakage pulse amplitude value is divided by the ultrasonic elastic wave energy value to obtain a wire breakage update coefficient; specifically, the magnetic flux leakage pulse amplitude value is divided by the ultrasonic elastic wave energy value, and the result is the wire breakage update coefficient; the wire breakage update coefficient is accumulated with the wire breakage coefficients of the continuous stroke numbers of the cable to update the theoretical cumulative wire breakage indicator; the theoretical cumulative wire breakage indicator before the current stroke number is read from the database, and the wire breakage update coefficient is added to the theoretical cumulative wire breakage indicator to obtain a new theoretical cumulative wire breakage indicator.

[0092] In another operation step of the embodiment, the updated theoretical cumulative wire breakage index is stored as a real-time cumulative wire breakage index, and the corresponding trip number and timestamp are associated; the storage format can be: {trip number, timestamp, real-time cumulative wire breakage index}, and these data are stored in a database for subsequent analysis and query.

[0093] Optionally, step S5 further comprises the following steps:

[0094] Step S54: count the total number of bending trips completed by the cable from the start of use to the current time, denoted as the used trip number;

[0095] Step S55: calculate the ratio of the real-time cumulative wire breakage index to the failure threshold to obtain the loss ratio; divide the used trip number by the loss ratio to obtain the theoretical total life trip number;

[0096] Step S56: subtract the used trip number from the theoretical total life trip number, and output the difference as the remaining life prediction value in the form of trip number.

[0097] In the embodiment, the total number of bending trips completed by the cable from the start of use to the current time is read from the database, and this number is denoted as the used trip number; the maximum value of all recorded trip numbers in the database is queried to obtain the used trip number. The ratio of the real-time cumulative wire breakage index to the failure threshold is calculated to obtain the loss ratio. Divide the real-time cumulative wire breakage index by the failure threshold to obtain the loss ratio. Divide the used trip number by the loss ratio to obtain the theoretical total life trip number. Specifically, divide the used trip number by the loss ratio to obtain the theoretical total life trip number. Subtract the used trip number from the theoretical total life trip number to obtain the remaining life prediction value. Subtract the used trip number from the theoretical total life trip number to obtain the remaining life prediction value. Output the remaining life prediction value in the form of trip number to enable the user to understand the remaining service life of the cable.

[0098] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application being defined by the appended claims rather than the above description, and it is intended to encompass all variations falling within the meaning and scope of the equivalent elements of the application file.

[0099] The above description is only a specific implementation of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cable life prediction method based on working condition motion, characterized in that: The following steps are involved: Step S1: A magnetic leakage ring is set on the outer periphery of the cable shielding layer, and the magnetic leakage ring has a built-in Hall array; Attaching an acoustic emission patch to the surface of the shielding layer; Install a mechanical trigger at the cable drag chain joint; Step S2: When the mechanical trigger detects a complete bending stroke, the Hall array and the acoustic emission patch are synchronously activated to generate the leakage magnetic pulse amplitude value and ultrasonic elastic wave energy value of the current stroke number; Step S3: Divide the magnetic flux leakage pulse amplitude value of the same stroke number by the ultrasonic elastic wave energy value to obtain the broken wire coefficient of the stroke number; accumulate the broken wire coefficients of consecutive cable stroke numbers to form a theoretical cumulative broken wire index; Step S4: Performing an accelerated bending test on the same type of cable on an accelerated bending test device until the cable fails, and recording the theoretical cumulative broken wire index at the time of failure as the failure threshold; Step S5: Monitor and obtain a real-time cumulative broken wire index, perform a proportional operation on the real-time cumulative broken wire index and the failure threshold, and output a predicted value of the remaining life of the cable.

2. The cable life prediction method based on working condition motion according to claim 1 is characterized in that: The mechanical trigger includes a first position sensor and a second position sensor respectively provided at two ends of the cable motion trajectory. In step S2, each time the mechanical trigger detects a complete bending stroke, the following steps are performed: When the first position sensor detects for the first time that the cable reaches the first limit bending position, the timer is started and marked as the starting point of the stroke; The cable continues to move to the second extreme bending position. When the second position sensor detects that the cable has reached this position, it is recorded as the midpoint of the stroke. The cable returns from the second extreme bending position. When the first position sensor detects that the cable has reached the first extreme bending position again, the timer is stopped and marked as the end point of the stroke.

3. The cable life prediction method based on working condition motion according to claim 2, characterized in that: In step S2, each time the mechanical trigger detects a complete bending stroke, the method further includes: The movement process of the cable within the time period recorded by the timer is defined as a complete bending stroke, wherein the time interval recorded by the timer is used as the period parameter of the complete bending stroke; When the first position sensor and the second position sensor both complete corresponding detection actions and the timer completes a full timing cycle, it is determined that a complete bending stroke is detected.

4. The cable life prediction method based on working condition motion according to claim 1, characterized in that: In step S2, the Hall array and the acoustic emission patch are synchronously started to generate the leakage magnetic pulse amplitude value and ultrasonic elastic wave energy value of the current stroke number, including: When the mechanical trigger detects a complete bending stroke and outputs a stroke trigger signal, it takes the rising edge of the stroke trigger signal as the starting point and synchronously sends a start instruction to the Hall array and the acoustic emission patch; After receiving the start command, the Hall array collects a set of leakage magnetic signals near the two extreme bending positions of the stroke. Each set of signals contains a continuous pulse waveform. Calculate the sum of the pulse amplitudes of each group of signals, and add the sums of the two groups as the leakage magnetic pulse amplitude value of the current trip number; After receiving the start command, the acoustic emission patch continuously collects the ultrasonic elastic wave signal of the entire stroke, monitors the energy value of the ultrasonic elastic wave signal in real time, and records a valid pulse when the energy value exceeds the preset energy value threshold; The total number of valid pulses in the stroke is counted and the energy sum of all valid pulses is calculated, and the energy sum is used as the ultrasonic elastic wave energy value of the current stroke number.

5. The cable life prediction method based on working condition motion according to claim 1, characterized in that: In step S4, the accelerated bending test on the same type of cable includes: Cut a cable sample from the middle of the same roll of cable and mark the starting point of the shield braiding direction before cutting; Measure the shielding layer thickness and insulation layer thickness of each cable sample, and filter out cable samples whose measurement value fluctuation range is within the preset range.

6. The cable life prediction method based on working condition motion according to claim 5, characterized in that: The accelerated bending test equipment includes a fixed base and a movable swing arm. The fixed base is provided with a base mark, and the movable swing arm is provided with a connection part. The cable sample installation operation performed before the accelerated bending test in step S4 is specifically as follows: Fix one end of the cable sample to the fixed base of the accelerated bending test equipment. When fixing, rotate the cable sample so that the inclination direction of the shielding layer braiding texture is aligned with the base identification line; Connect the other end of the cable sample to the movable swing arm of the accelerated bending test equipment, and install a positioning ring at the connection part. The inner ring of the positioning ring fits tightly with the insulation layer of the sample, and the outer ring forms a clearance fit with the slot of the swing arm. Adjust the distance between the fixed base and the movable swing arm so that when the cable sample droops naturally, there are no stretch wrinkles on the shielding layer and no tension marks on the surface of the insulation layer.

7. The cable life prediction method based on working condition motion according to claim 6, characterized in that: The determination of cable function failure in step S4 is specifically as follows: During the accelerated bending test, after each bending cycle, use a probe to gently poke the edge of the shield layer to identify whether there are new broken wires or warping; Use light transmission to detect the insulation layer. Place the light source on one side of the cable sample and use a light screen to receive the light on the other side. Record the number and shape of light spots appearing on the light screen. When the number of broken wires of the shielding layer exceeds a preset number of broken wires, or irregular light spots exceeding a preset number of light spots appear on the light screen, the accelerated bending test of the cable sample is terminated.

8. The cable life prediction method based on working condition motion according to claim 7, characterized in that: The theoretical cumulative broken wire index recorded at the time of failure in step S4 includes: After the cable sample is tested, the shielding layer is disassembled and the broken wires are sorted out. The broken wires are classified and counted by length to obtain the broken wire classification results. Strip the insulation layer, measure the straight-line distance between the starting point of the crack and the clamping point, record the extension direction of each crack, and obtain crack measurement data; Determine the theoretical cumulative broken wire index based on the broken wire classification counting results and crack measurement data; The theoretical cumulative broken wire indexes of all samples are sorted, and the value in the middle position of the sorted sequence is taken as the failure threshold.

9. The cable life prediction method based on working condition motion according to claim 1, characterized in that: Step S5 includes the following steps: Step S51: after each complete bending stroke, updating the magnetic flux leakage pulse amplitude value and ultrasonic elastic wave energy value corresponding to the stroke in the database; Step S52: Dividing the updated magnetic flux leakage pulse amplitude value and the ultrasonic elastic wave energy value to obtain a broken wire update coefficient, and accumulating the broken wire update coefficient with the broken wire coefficients of the continuous cable travel numbers to update the theoretical accumulated broken wire index; Step S53: storing the updated theoretical cumulative broken wire index as the real-time cumulative broken wire index, and associating it with the corresponding trip number and timestamp.

10. The cable life prediction method based on working condition motion according to claim 9, characterized in that: Step S5 further includes the following steps: Step S54: Counting the total number of bending strokes completed by the cable from the beginning of use to the current moment, and recording it as the number of used strokes; Step S55: Calculate the ratio of the real-time cumulative broken wire index to the failure threshold to obtain the loss ratio; divide the used strokes by the loss ratio to obtain the theoretical total life strokes; Step S56: Subtract the number of used trips from the theoretical total life trips, and use the difference as the remaining life prediction value and output it in the form of trip numbers.

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