Insulation resistance testing method and system for high-flexibility combined signal cable

Abstract

The present application relates to the technical field of high-flexibility combined signal cable, and particularly relates to an insulation resistance test method and system for high-flexibility combined signal cable. The method comprises the following steps: based on the real leakage current waveforms of each wire core under various preset working conditions, calculating the similarity between the real leakage current waveforms under various preset working conditions, and then determining the disturbed wire core and the wire core causing interference to it; based on the similarity of the wire core causing interference and the disturbed wire core, compensating the real leakage current of each wire core causing interference to obtain the real leakage current of the compensated disturbed wire core, and then calculating the insulation resistance of each wire core in the high-flexibility combined signal cable to be tested. The dynamic coupling noise characteristics between the wire cores in the high-flexibility combined signal cable are effectively extracted and filtered out, and the precision is higher than that before compensation, which can truly reflect the dielectric loss and fatigue degree of the material in high-flexibility movement.

Description

Technical Field

[0001] This invention relates to the field of highly flexible composite signal cable technology, and more specifically to an insulation resistance testing method and system for highly flexible composite signal cables. Background Technology

[0002] Currently, traditional insulation resistance testing mainly relies on static point-to-point measurements using high-voltage megohmmeters. While this method is stable when testing ordinary cables, it has significant limitations for highly flexible composite cables. Highly flexible cables are often under continuous or intermittent mechanical motion in actual operation, such as the repetitive swinging of robotic arms or the frequent displacement of mobile equipment. Under these dynamic conditions, the cable insulation layer constantly undergoes stretching, compression, and bending deformation, leading to microscopic changes in its internal structure. Simultaneously, the insulation material in the cable generates piezoelectric effects and triboelectric noise, resulting in high mechanical stress interference between different cores within the cable, directly affecting insulation performance. Traditional static testing methods completely fail to capture this dynamic process, leading to significant deviations between test results and actual conditions. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a method and system for testing the insulation resistance of highly flexible composite signal cables. The specific technical solution adopted is as follows:

[0004] In a first aspect, the present invention provides a method for testing the insulation resistance of highly flexible composite signal cables, comprising the following steps:

[0005] 1) Obtain the actual leakage current waveforms of each core in the highly flexible combined signal cable under various preset working conditions;

[0006] 2) Based on the actual leakage current waveforms of each wire core under various preset operating conditions, calculate the similarity between the actual leakage current waveforms under various preset operating conditions, and then determine the wire core that is interfered with and the wire core that causes interference to it.

[0007] 3) Based on the similarity between the interference-causing wire core and the interference-affected wire core and the actual leakage current of each interference-causing wire core, the actual leakage current of the interference-affected wire core is corrected and compensated to obtain the compensated actual leakage current of the interference-affected wire core.

[0008] 4) Based on the actual leakage current of the interfered conductor after compensation and the actual leakage current of the conductor causing the interference, calculate the insulation resistance of each conductor in the high-flexibility combined signal cable to be tested.

[0009] In conjunction with the first aspect mentioned above, among some possible implementation methods, the method for correcting and compensating the actual leakage current of the disturbed conductor to obtain the compensated actual leakage current of the disturbed conductor is as follows:

[0010] Based on the similarity between the interference-causing wire core and the interfered wire core, and the AC component of the actual leakage current of each interference-causing wire core, the AC component of the actual leakage current of the interfered wire core after compensation is obtained, and thus the actual leakage current of the interfered wire core after compensation is obtained.

[0011] In conjunction with the first aspect above, among some possible implementations, methods for obtaining the AC component of the true leakage current of the disturbed conductor after compensation include:

[0012] Based on the similarity between the interference-causing wire core and the interfered wire core, the reference coupling coefficient under the corresponding set operating conditions, and the AC component of the actual leakage current of each interference-causing wire core, the interference waveform caused by the interference-causing wire core to the interfered wire core is obtained. Then, based on the interference waveform and the AC component of the actual leakage current of the interfered wire core, the AC component of the actual leakage current of the interfered wire core after compensation is obtained.

[0013] In conjunction with the first aspect above, in some possible implementations, the actual leakage current of the conductor causing the interference is the actual leakage current after alignment with the actual leakage current of the conductor being interfered with. The alignment method is as follows:

[0014] Calculate the instantaneous distance between the actual leakage current of the conductor causing the interference and the actual leakage current of the conductor affected by the interference at any time, and then construct an instantaneous distance matrix;

[0015] Based on the constructed instantaneous distance matrix, determine the path with the minimum instantaneous distance from the starting point to the ending point of the matrix;

[0016] Extract the actual leakage current of the interference-causing wire cores corresponding to each distance in the path, and sort them according to the time sequence of the actual leakage current of the interference-causing wire cores corresponding to each distance to obtain the aligned actual leakage current of the interference-causing wire cores.

[0017] In conjunction with the first aspect mentioned above, among some possible implementations, methods for determining the path with the minimum instantaneous distance from the starting point to the ending point of the matrix based on the constructed instantaneous distance matrix include:

[0018] Starting from the end of the instantaneous distance matrix, select the optimal cell with the smallest instantaneous distance from the three cells adjacent to it, and then select the cell with the smallest instantaneous distance from the three cells adjacent to the optimal cell as the new optimal cell, until the starting point of the instantaneous similarity matrix is ​​reached.

[0019] The continuous path formed by the endpoint, all selected optimal cells, and the starting point is taken as the path with the minimum instantaneous distance from the matrix starting point to the matrix endpoint.

[0020] In conjunction with the first aspect mentioned above, among some possible implementations, the method for determining the interfered wire core and the wire core causing the interference is as follows:

[0021] For any two wire cores, based on the similarity of their actual leakage current waveforms under various preset operating conditions, determine whether they interfere with each other under various preset operating conditions. Based on the number of preset operating conditions where they interfere with each other and the total number of preset operating conditions, determine the probability that they interfere with each other. If the probability that they interfere with each other is higher than the set threshold for the probability of interference, then they are determined to interfere with each other.

[0022] The conductor with the smaller actual AC leakage current component among the two conductors involved in the interference is identified as the conductor affected by the interference, and the conductor with the larger actual leakage current component is identified as the conductor causing the interference.

[0023] In conjunction with the first aspect above, in some possible implementations, the method for calculating the similarity between the actual leakage current waveforms under various preset operating conditions includes: calculating the DTW distance between the actual leakage current waveforms of any two wire cores under various preset operating conditions, and then obtaining the similarity between the actual leakage current waveforms under various preset operating conditions.

[0024] In conjunction with the first aspect mentioned above, among some possible implementation methods, the method for obtaining the actual leakage current waveform of each core in the highly flexible combined signal cable under various preset operating conditions is as follows:

[0025] The leakage current waveforms of each wire core under various preset operating conditions are obtained, and the reference background noise waveform is subtracted to obtain the actual leakage current waveforms of each wire core under various preset operating conditions.

[0026] The reference background noise waveform is the periodic interference current waveform generated by cable deformation, extracted using an adaptive filtering algorithm.

[0027] In conjunction with the first aspect mentioned above, in some possible implementations, the adaptive filtering algorithm is the least mean square algorithm.

[0028] Secondly, the present invention also provides an insulation resistance testing system for highly flexible composite signal cables, including a dynamic load simulation subsystem, an electrical measurement subsystem, and a main controller. The main controller is used to control the dynamic load simulation subsystem to simulate different preset working conditions. The main controller also obtains the leakage current of each core under different working conditions through the electrical measurement subsystem. The main controller is also used to implement the insulation resistance testing method for highly flexible composite signal cables of the present invention based on the leakage current waveform of each core under different working conditions.

[0029] The beneficial effects of this invention are as follows: First, based on the actual leakage current waveforms of each core under various preset operating conditions, this invention calculates the similarity between the actual leakage current waveforms, thereby determining the interfered cores and the cores causing the interference. This allows for a more dynamic and accurate determination of the interfered cores and the cores causing the interference in the cable under different preset operating conditions. Furthermore, based on the similarity and the actual leakage current of each core causing the interference, this invention compensates for the actual leakage current of all interfered cores, obtaining the compensated actual leakage current of the interfered cores. By compensating for the actual leakage current of the interfered cores using the actual leakage current of the cores causing the interference, the dynamic coupling noise characteristics between the cores in the highly flexible combined signal cable are effectively extracted and filtered out. Finally, the insulation resistance values ​​of each interfered core after compensation have higher accuracy than before compensation, and can truly reflect the dielectric loss and fatigue degree of the material in highly flexible motion. Attached Figure Description

[0030] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A flowchart of a method for testing the insulation resistance of a highly flexible composite signal cable according to an embodiment of the present invention. Detailed Implementation

[0032] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0033] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0034] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0035] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0036] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0037] Although operations or steps are described in a specific order in the accompanying drawings in the embodiments of the present invention, this should not be construed as requiring these operations or steps to be performed in the specific order or serial order shown, or requiring all of the shown operations or steps to be performed to obtain the desired result. In the embodiments of the present invention, these operations or steps may be performed serially; they may be performed in parallel; or a portion of these operations or steps may be performed.

[0038] Meanwhile, it is understood that the data involved in the technical solutions of this invention (including but not limited to the data itself, the acquisition or use of the data) shall comply with the requirements of relevant laws, regulations and related provisions. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by those skilled in the art to which this invention pertains. Furthermore, in all division and logarithmic operations involved in this invention, a protection mechanism is employed to prevent computational crashes or invalid values ​​due to a zero denominator or zero input. The implementation of this protection mechanism can be reasonably set according to the actual situation. For example, when the denominator term of a division operation or the argument term of a logarithmic function is zero, a protection parameter with the same dimension as or dimensionless as the denominator term or the argument term can be added. The value of this protection parameter can be a very small value greater than zero, thereby ensuring the robustness and feasibility of the algorithm under extreme conditions. In addition, the normalization function mentioned in this invention, unless otherwise specifically stated, uses maximum-minimum value normalization to normalize the normalization result to the [0, 1] interval or other continuous intervals. The maximum and minimum values ​​used in the maximum-minimum normalization can be obtained according to the actual situation. For example, when multiple values ​​can be obtained in the implementation process and it is necessary to compare the relationship between different values, multiple values ​​can be counted to obtain the maximum and minimum values. However, when only a single value can be obtained in the implementation process, the maximum and minimum values ​​can be obtained by counting based on a large amount of historical experimental data or prior data obtained in the early stage.

[0039] The insulation resistance testing system for highly flexible composite signal cables of the present invention includes a dynamic load simulation subsystem, an electrical measurement subsystem, and a synchronous control and data processing subsystem.

[0040] The dynamic load simulation subsystem consists of a motion control platform (including servo drivers, fixtures, force sensors, displacement sensors, etc.) and a motion degree control unit. It is used to simulate various working conditions of cables, such as bending, tension, compression, or torsion, through a high-precision mechanical structure. The motion degree control unit controls the motion platform according to preset working conditions (such as reciprocating motion at 10 mm / s, bending at 90 degrees per second, etc.).

[0041] The electrical measurement subsystem consists of a high-voltage DC source and a leakage current measurement circuit (comprising a transimpedance amplifier and a high-precision analog-to-digital converter). The high-voltage DC source generates a stable test voltage, which is applied between the cable's conductor and shield. The transimpedance amplifier converts the minute current into a voltage signal, facilitating the acquisition of core leakage current data. The high-precision analog-to-digital converter converts the analog signal into a digital signal and restores it to the corresponding core leakage current signal.

[0042] The synchronous control and data processing system consists of a main controller and a data preprocessing unit. The main controller controls the dynamic load simulation subsystem and the electrical measurement subsystem, and acquires data from both in real time. Specifically, the main controller uses high-precision sensors such as encoders, linear scales, potentiometers, and displacement sensors to acquire the cable's motion trajectory data to simulate different operating conditions of the highly flexible combined signal cable. The main controller also uses a high-precision analog-to-digital converter in the electrical measurement subsystem to acquire the leakage current waveforms of each conductor under different operating conditions. The main controller is also used to test the cable's insulation resistance based on the leakage current waveforms of each conductor under different operating conditions. Specific testing methods are as follows... Figure 1 As shown, it includes the following steps:

[0043] Step 1: For the high-flexibility combined signal cable to be tested, perform insulation resistance tests under different preset operating conditions to obtain the actual leakage current waveform of each core and the voltage to ground of each core under different operating conditions.

[0044] In this embodiment, it is assumed that there are R different preset operating conditions, and the high-flexibility composite signal cable to be tested has a total of M cores. Each core of the high-flexibility composite cable is electrically independent in structure, and the mechanical stress borne by different cores is also different under different operating conditions. Therefore, the leakage current waveforms of different cores are different, and it is necessary to collect the leakage current waveforms of each core under different operating conditions.

[0045] The leakage current waveform obtained by direct detection is affected by the periodic interference current waveform and is not the true leakage current waveform. Therefore, in this embodiment, in order to prevent the interference current waveform from affecting the accuracy of the insulation test, it is necessary to remove the periodic interference current waveform first. The specific method is as follows: 1. Under the condition of applying a preset test voltage to each conductor, control the servo driver to perform 10-50 cycles of no-load reciprocating motion. During this period, two data streams are collected synchronously: one is the real-time dynamic micro-current signal generated on the conductor; the other is the real-time mechanical phase angle fed back by the servo driver. 2. The collected real-time dynamic micro-current signal is used as the original input signal, and the synchronously collected real-time mechanical phase angle is used as the periodic reference signal, and both are input to the adaptive filtering algorithm (such as the LMS algorithm). 3. The adaptive filtering algorithm (the LMS algorithm, i.e., the least mean square algorithm, is used in this embodiment) uses the mechanical phase angle as the synchronization reference to filter out the random electrical noise in the dynamic micro-current signal, outputs a pure current waveform with the same frequency as the mechanical motion, and records the output result as the reference background noise waveform of the high-flexibility composite cable. 4. Using the leakage current waveforms of each conductor under various operating conditions obtained from the test, subtract the reference background noise waveform to obtain the actual leakage current waveforms of each conductor under various operating conditions.

[0046] Step 2: Based on the leakage current waveforms of each wire core under different preset operating conditions, calculate the similarity of the leakage current waveforms, and then determine the wire core that is being interfered with, and determine the degree of interference of the interfered wire core.

[0047] In this embodiment, the method for determining whether a wire core is subject to interference according to the present invention is described using the m-th wire core and the (m+1)-th wire core as examples, as follows:

[0048] 2.1 Calculate the similarity of the actual leakage current waveforms of the m-th core and the (m+1)-th core under various operating conditions, and determine whether the m-th core and the (m+1)-th core interfere with each other under various operating conditions.

[0049] Specifically, taking the r-th preset operating condition as an example, the similarity between the actual leakage current waveforms of the m-th core and the (m+1)-th core under this condition is calculated and denoted as . If the similarity between the actual leakage current waveforms of the two conductors is greater than the set similarity threshold, then interference is determined to have occurred between the two conductors under the r-th operating condition. The set similarity threshold is an empirical value obtained from the noise correlation statistics of a typical high-flexibility cable under the preset operating conditions, which is the boundary value between the degree of similarity between interference and non-interference. For example, the set similarity threshold is set to 0.3.

[0050] In one implementation, the similarity of the actual leakage current waveforms of the m-th core and the (m+1)-th core is... The calculation method is as follows:

[0051] Calculate the DTW (Dynamic Time Warping) distance between the actual leakage current waveforms of the m-th core and the (m+1)-th core, and normalize it (in this embodiment, the normalization process adopts min-max normalization, and the normalization reference is the maximum and minimum values ​​within the current test cycle. Other normalization methods can also be used in other embodiments. The larger the DTW distance, the smaller the normalized value obtained after normalization). This yields the similarity between the actual leakage current waveforms of the m-th core and the (m+1)-th core. .

[0052] 2.2. Based on the percentage of operating conditions where interference exists in the m-th and (m+1)-th wire cores, determine the probability of actual mechanical stress interference in the m-th and (m+1)-th wire cores, denoted as [missing information]. .

[0053] In this embodiment, there is a possibility that the m-th core and the (m+1)-th core may experience real mechanical stress interference. The calculation method is as follows:

[0054]

[0055] In the formula, R represents the total number of working conditions where the m-th core and the (m+1)-th core are subject to actual mechanical stress interference, and R represents the total number of all preset working conditions.

[0056] 2.3. Based on the possibility of real mechanical stress interference between the m-th core and the (m+1)-th core, determine whether there is mechanical stress interference between these two cores.

[0057] In this embodiment, when the probability of actual mechanical stress interference between the m-th core and the (m+1)-th core is greater than the probability threshold of mechanical interference, it is determined that there is mechanical interference between the m-th core and the (m+1)-th core.

[0058] The probability threshold for mechanical interference is an empirical value determined based on historical data of actual interference. The specific determination method is as follows: similarity data and the proportion of operation of standard intact cables in the interference-free state are collected in advance, and the upper limit edge value of their statistical distribution is set as the similarity threshold and the probability threshold, respectively. In this embodiment, the probability threshold is specifically set to 0.5.

[0059] The above method is used to determine whether there is mechanical stress interference between any two cores in the high-flexibility combined signal cable under test.

[0060] 2.4 Repeat steps 2.1 to 2.3 to determine whether there is interference between any two wires in the M wires.

[0061] Step 3: Under a preset operating condition, based on the actual leakage current of each interference core, compensate for the actual leakage current of all interfered cores to obtain the compensated actual leakage current of the interfered cores.

[0062] 3.1 Determine the interference and affected relationship between two wire cores that are subject to mechanical stress interference, identify the affected wire core, and all wire cores that interfere with the affected wire core.

[0063] Since interference sources in composite cables typically possess high signal energy, the conductor with the smaller root mean square (RMS) value in the leakage current waveform is designated as the affected conductor. In this embodiment, the RMS (root mean square) of the AC waveform (excluding the DC component) of the actual leakage current waveforms of the m-th and (m+1)-th conductors is calculated for each of various preset operating conditions. Under a given preset operating condition, the conductor with the smaller RMS value is identified as the affected conductor under that condition, and the other conductor is identified as the conductor causing the interference under that condition.

[0064] For example, if the root mean square (RMS) of the (m+1)th conductor under the r-th operating condition is less than the RMS RMS of the m-th conductor, it can be determined that the (m+1)th conductor under the r-th operating condition is the conductor subject to interference, and the m-th conductor is the conductor generating interference. When the m-th conductor carries a large current or undergoes deformation, the (m+1)th conductor will be interfered with. The interference and interference relationship between the m-th conductor and the (m+1)th conductor may differ under different preset operating conditions.

[0065] Then, all the wire cores that interfere with the (m+1)th wire core are identified. In this embodiment, the interference of the (m+1)th wire core by the three wire cores (m-1, m-2) under the r-th working condition is used as an example for explanation.

[0066] Since mechanical stress interference is usually chain-like for M linear combined signal cables, the core that generates interference will also be affected by other cores (e.g., the (m+1)th core is affected by the mth core, the mth core is affected by the (m-1)th core, etc.), in this embodiment, the actual leakage current waveform of each affected core is compensated in order of the degree of interference from high to low.

[0067] In this embodiment, taking the r-th preset working condition as an example, the specific compensation method includes:

[0068] 3.2 Calculate the degree of interference of the affected wire cores and sort them in descending order of interference degree.

[0069] The method for calculating the degree of interference is as follows: obtain the similarity of the actual leakage current waveforms of each interference-generating wire core (m, m-1, and m-2) and the interfered wire core (m+1). , and Calculate the similarity , and The sum of these values, after normalization, yields the degree of interference for all affected wire cores, denoted as [missing information]. The normalization method used is maximum-minimum value normalization.

[0070] For ease of explanation, this embodiment uses the (m+1)th wire as an example to illustrate the situation where the interference level is the highest, and assumes that the (m+2)th wire is less affected by interference and is also affected by the (m+1)th wire.

[0071] 3.3 Align the actual leakage current of the conductor causing the interference under the r-th preset operating condition with the actual leakage current of the conductor being interfered with.

[0072] Because the transmission of mechanical stress within highly flexible composite cables involves wave velocity differences and phase lag, direct subtraction can lead to signal misalignment. Therefore, it is first necessary to align the actual leakage current waveform sequences of the interfering and affected conductors before subtracting them for compensation. In this embodiment, the method for aligning the interfering and affected conductors is as follows:

[0073] Taking the m-th and (m+1)-th conductors as examples, under the r-th preset operating condition, the actual leakage current sequence of the m-th conductor is as follows: The actual leakage current sequence of the (m+1)th conductor is .

[0074] 3.3.1 Calculation and The instantaneous distance between any two points in time, for example and instantaneous distance D ( , ), and instantaneous distance D ( , ), ..., and instantaneous distance D ( , ), get a The distance matrix, where the data in the i-th row and j-th column is... and instantaneous distance D ( , In this real-time mode and The instantaneous distance is represented by the absolute value of the difference between the two.

[0075] 3.3.2. Based on the constructed distance matrix, the optimal path (the path with the highest instantaneous similarity) between the starting point (1,1) and the ending point (I,J) is solved. In this embodiment, the optimal path of the similarity matrix from the ending point (I,J) to the starting point is determined by backtracking from the ending point (I,J). Specifically, starting from the ending point (I,J), the path is calculated by looking at the three adjacent cells before it (I,J). In the given information, select the cell with the smallest instantaneous distance as the optimal cell for that location. Let's assume it's cell number 1. Then further in The three adjacent cells in front The cell with the smallest instantaneous distance is selected as the optimal cell at that position, and so on, until the starting point (1,1) is reached. The continuous path formed by the ending point, all the selected optimal cells, and the starting point is taken as the optimal path of the distance matrix.

[0076] 3.3.3 Construct a blank sequence of the same length as the actual leakage waveform sequence of the interfered core. Taking the (m+1)th core as an example, the length of the constructed blank sequence is J. The actual leakage currents of the interfering core (the m-th core) corresponding to each instantaneous similarity along the optimal path of the similarity matrix are filled into the constructed blank sequence according to the time order (i.e., the j value) of the interfered core (the (m+1)-th core). This yields the aligned actual leakage current waveform of the interfering core (the m-th core). The aligned data filled into the blank sequence is then smoothed by low-pass filtering and denoted as... This is to eliminate discrete step abrupt changes introduced by time-scale recalculation.

[0077] If multiple times i in the optimal path correspond to the same time j (i.e., the interference signal is compressed at this point), then the current values ​​corresponding to these times j are averaged. If time i corresponds to multiple times j (i.e., the interference signal needs to be stretched at this point), then the current at that time is filled into all corresponding positions in the new sequence.

[0078] 3.3.4 Repeat steps 3.2.1 to 3.2.3 to obtain the aligned true leakage current waveforms of all interfering wires (the m-th wire, the (m-1)-th wire, and the (m-2)-th wire) that cause interference to the m+1 wires. , and .

[0079] 3.4. Based on the similarity between the interference-causing wire core and the interfered wire core, and the actual leakage current waveform after the alignment of each interference-causing wire core, the actual leakage current waveform of the interfered wire core is compensated to obtain the compensated actual leakage current waveform of the interfered wire core.

[0080] Since direct subtraction results in the loss of DC leakage current and causes an artificially high insulation resistance calculation, this embodiment compensates by subtracting the AC component of the actual leakage current waveform of the interfered core from the AC component of the actual leakage current waveform of the aligned cores.

[0081] In this embodiment, the specific compensation method is as follows:

[0082]

[0083] In the formula, This is the AC component sequence of the actual leakage current after compensation for the (m+1)th conductor. V is the AC component sequence of the actual leakage current before compensation for the (m+1)th wire core, and V is the total number of wire cores that cause interference to the (m+1)th wire core. In this embodiment, V=3, and v represents all wire cores that cause interference to the (m+1)th wire core, v=(1,2,3). , and These are the actual leakage current waveforms after alignment. , and The amount of communication, , and Numerically equal to , and , The reference coupling coefficient is obtained through experimental measurement under the r-th preset operating condition. Specifically, under static no-load conditions, a known AC test signal is applied to a single interfering conductor, and the induced current on the affected conductor is measured. The ratio of the two values ​​is used as the reference coupling coefficient. The above formula indicates that, based on similarity... Aligned AC component sequence of the actual leakage current of the conductor causing interference and reference coupling coefficient The interference waveform of the interference core to the affected core is calculated. Then, the AC component waveform of the actual leakage current of the affected core is used to subtract the mean of each interference waveform to obtain the AC component sequence of the actual leakage current of the affected core after compensation.

[0084] AC component sequence of the actual leakage current after compensation for the (m+1)th conductor. Adding the other decomposed components of the conductor, we obtain the compensated true leakage current sequence of the (m+1)th conductor.

[0085] 3.5. Repeat step 3.3 in descending order of interference level to compensate for the actual leakage current of other interfered conductors until the compensated actual leakage current of all interfered conductors is obtained.

[0086] Step 4: Based on the actual leakage current of each interfered conductor after compensation and the voltage to ground of each conductor, calculate the instantaneous dynamic insulation resistance sequence of all conductors in the high-flexibility combined signal cable to be tested.

[0087] Through the above steps, the instantaneous dynamic insulation resistance sequence of each interfered wire core obtained after compensation effectively extracts and filters out the dynamic coupling noise characteristics between the wire cores in the high-flexibility combined signal cable. Compared with the original compensation, it has higher accuracy and can truly reflect the dielectric loss and fatigue degree of the material in high-flexibility motion.

[0088] Step 5: Under other preset operating conditions, repeat steps 3 to 4 to obtain the instantaneous dynamic insulation resistance sequence of each core in the highly flexible combined signal cable under various preset operating conditions.

[0089] Based on the same inventive concept, the present invention also provides a method for testing the insulation resistance of a highly flexible combined signal cable, the specific process and principle of which are described in steps two to five above.

Claims

1. A method for testing the insulation resistance of highly flexible composite signal cables, characterized in that, Includes the following steps: 1) Obtain the actual leakage current waveforms of each core in the highly flexible combined signal cable under various preset working conditions; 2) Based on the actual leakage current waveforms of each wire core under various preset operating conditions, calculate the similarity between the actual leakage current waveforms under various preset operating conditions, and then determine the wire core that is interfered with and the wire core that causes interference to it. 3) Based on the similarity between the interference-causing wire core and the interference-affected wire core and the actual leakage current of each interference-causing wire core, the actual leakage current of the interference-affected wire core is corrected and compensated to obtain the compensated actual leakage current of the interference-affected wire core. The actual leakage current of the conductor causing the interference is the actual leakage current after alignment with the actual leakage current of the conductor being interfered with. The alignment method is as follows: Calculate the instantaneous distance between the actual leakage current of the conductor causing the interference and the actual leakage current of the conductor affected by the interference at any time, and then construct an instantaneous distance matrix; Based on the constructed instantaneous distance matrix, determine the path with the minimum instantaneous distance from the starting point to the ending point of the matrix; Extract the actual leakage current of the interference-causing wire core corresponding to each distance in the path, and sort them according to the time sequence of the actual leakage current of the interference-causing wire core corresponding to each distance to obtain the aligned actual leakage current of the interference-causing wire core. 4) Based on the actual leakage current of the interfered conductor after compensation and the actual leakage current of the conductor causing the interference, calculate the insulation resistance of each conductor in the high-flexibility combined signal cable to be tested.

2. The insulation resistance testing method for highly flexible composite signal cables according to claim 1, characterized in that, The method for correcting and compensating the actual leakage current of the disturbed conductor to obtain the compensated actual leakage current of the disturbed conductor is as follows: Based on the similarity between the interference-causing wire core and the interfered wire core, and the AC component of the actual leakage current of each interference-causing wire core, the AC component of the actual leakage current of the interfered wire core after compensation is obtained, and thus the actual leakage current of the interfered wire core after compensation is obtained.

3. The insulation resistance testing method for highly flexible composite signal cables according to claim 2, characterized in that, Methods for obtaining the AC component of the true leakage current of the interfered conductor after compensation include: Based on the similarity between the interference-causing wire core and the interfered wire core, the reference coupling coefficient under the corresponding set operating conditions, and the AC component of the actual leakage current of each interference-causing wire core, the interference waveform caused by the interference-causing wire core to the interfered wire core is obtained. Then, based on the interference waveform and the AC component of the actual leakage current of the interfered wire core, the AC component of the actual leakage current of the interfered wire core after compensation is obtained.

4. The insulation resistance testing method for highly flexible composite signal cables according to claim 1, characterized in that, Methods for determining the path with the minimum instantaneous distance from the starting point to the ending point of the matrix based on the constructed instantaneous distance matrix include: Starting from the end of the instantaneous distance matrix, select the optimal cell with the smallest instantaneous distance from the three cells adjacent to it, and then select the cell with the smallest instantaneous distance from the three cells adjacent to the optimal cell as the new optimal cell, until the starting point of the instantaneous similarity matrix is ​​reached. The continuous path formed by the endpoint, all selected optimal cells, and the starting point is taken as the path with the minimum instantaneous distance from the matrix starting point to the matrix endpoint.

5. The insulation resistance testing method for highly flexible combined signal cables according to claim 1, characterized in that, The method for identifying the affected wire core and the wire core causing the interference is as follows: For any two wire cores, based on the similarity of their actual leakage current waveforms under various preset operating conditions, determine whether they interfere with each other under various preset operating conditions. Based on the number of preset operating conditions where they interfere with each other and the total number of preset operating conditions, determine the probability that they interfere with each other. If the probability that they interfere with each other is higher than the set threshold for the probability of interference, then they are determined to interfere with each other. The conductor with the smaller actual AC leakage current component among the two conductors involved in the interference is identified as the conductor affected by the interference, and the conductor with the larger actual leakage current component is identified as the conductor causing the interference.

6. The insulation resistance testing method for highly flexible combined signal cables according to claim 1, characterized in that, The method for calculating the similarity between the actual leakage current waveforms under various preset operating conditions includes: calculating the DTW distance between the actual leakage current waveforms of any two conductors under various preset operating conditions, and then obtaining the similarity between the actual leakage current waveforms under various preset operating conditions.

7. The insulation resistance test method for highly flexible combined signal cables according to any one of claims 1-6, characterized in that, The method for obtaining the actual leakage current waveforms of each core in the highly flexible combined signal cable under various preset operating conditions is as follows: The leakage current waveforms of each wire core under various preset operating conditions are obtained, and the reference background noise waveform is subtracted to obtain the actual leakage current waveforms of each wire core under various preset operating conditions. The reference background noise waveform is the periodic interference current waveform generated by cable deformation, extracted using an adaptive filtering algorithm.

8. The insulation resistance testing method for highly flexible composite signal cables according to claim 7, characterized in that, The adaptive filtering algorithm is the least mean square algorithm.

9. An insulation resistance testing system for highly flexible composite signal cables, characterized in that, The system includes a dynamic load simulation subsystem, an electrical measurement subsystem, and a main controller. The main controller controls the dynamic load simulation subsystem to simulate different preset working conditions. The main controller also obtains the leakage current of each core under different working conditions through the electrical measurement subsystem. The main controller is also used to implement the insulation resistance test method for highly flexible combined signal cables as described in any one of claims 1-8 based on the leakage current waveform of each core under different working conditions.

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