A method, system and equipment for stranding control of zero-defect superconducting wire

Abstract

This invention belongs to the field of smart grid industry and provides a stranding control method, system, and device for zero-defect superconducting wires. It calculates the integer closest to the actual cable lay length and lay length consistency ratio as the target integer for multiple consistency, and uses the absolute value of the difference between the lay length consistency ratio and the target integer as the multiple consistency deviation. When the multiple consistency deviation exceeds the multiple consistency tolerance limit, the stranding speed and / or traction line speed are controlled to make the cable lay length approach the combination of the target integer and the strand twist pitch value. This achieves timely identification, smooth correction, and process traceability of lay length multiple consistency deviations while meeting structural and mechanical process constraints, thereby improving product consistency and process controllability.

Description

Technical Field

[0001] This invention belongs to the smart grid industry and the field of automatic control, and specifically relates to a stranding control method, system and equipment for zero-defect superconducting wire. Background Technology

[0002] With the expansion and upgrading of urban power grids, the increase in high-current dedicated lines, data center power supply, and urban rail transit, high-temperature superconducting cables are considered an important emerging power transmission solution due to their large capacity, low loss, self-limiting current, and environmental friendliness. They have already been demonstrated and are being industrialized in various application scenarios. Currently, superconducting cable systems typically require cryogenic maintenance conditions. In engineering, cryogenic environments such as liquid nitrogen temperature zones are often used to maintain the superconducting state, along with supporting refrigeration, insulation, and monitoring systems. Related projects place higher demands on manufacturing quality consistency and operational reliability. In conjunction with industry development, a complete industrial chain has been formed, covering material production, cryogenic refrigeration, cable integration, and cable applications, with continuous iteration in equipment and processes such as strip conductor stranding, cryogenic insulation wrapping, and vacuum insulation sleeves.

[0003] In the manufacturing process of superconducting conductors and cables, conductors are typically formed from multiple strands of superconducting wire or tape through multi-stage stranding, compression, and wrapping. This process must not only meet geometric specifications such as structural shape, outer diameter, and porosity, but also avoid excessive stretching, flattening, bending, or other mechanical damage to the superconducting material. Furthermore, process parameters such as stranding pitch, payoff tension, and untwisting methods at different stages often require strict control; otherwise, problems such as wire breakage, out-of-tolerance outer diameter, and structural instability can easily occur. Taking superconducting cables used in nuclear fusion devices as an example, because the outer diameter and porosity of each stage of the cable have a significant impact on electromagnetic performance, the control requirements for outer diameter and porosity during stranding are extremely stringent. Stranding using conventional methods may result in wire breakage, flattening, and difficulty in achieving the required outer diameter.

[0004] In the existing technologies of the intelligent manufacturing equipment industry, various solutions for the manufacturing and stranding of superconducting cable conductors have been disclosed. For example, patent document CN101123130A discloses a manufacturing method for low-temperature superconducting cable conductors used in the ITER system, employing multi-stage stranding combined with stainless steel strip wrapping and other processes. Its background section points out that when using cable stranding technology or combined winding methods, there are problems such as difficulty in tension control, easy breakage of the superconducting strip, the need for welding after strip breakage affecting performance, and difficulty in guaranteeing quality. Another example is patent document CN105989933A, which discloses a stranding method for superconducting cables used in fusion, employing multi-stage stranding, compression, loop wrapping, and overlapping, and setting an upper limit on the release tension to avoid damage to the superconducting strands and control the outer diameter. Its background section similarly emphasizes the strict control of outer diameter and porosity, and points out that conventional stranding methods may lead to defects such as wire breakage, flattening, and substandard outer diameter. However, from the perspective of zero-defect superconducting wire applications, the aforementioned existing technologies mainly focus on multi-stage stranding structures and geometric and mechanical process control such as tension / compression / outer diameter. They lack a quantifiable online control framework oriented towards the production process to address the consistency of the multiple between the cable lay pitch and the strand twist pitch, and its impact on electrical performance consistency. Furthermore, existing technologies often employ fixed pitch ratios or empirically set parameters, lacking a unified mechanism for identifying, triggering, and traceably recording lay pitch deviations based on real-time linear velocity and stranding speed during production. If the cable lay pitch and strand twist pitch meet the matching consistency requirements, the current transfer between filaments caused by periodic bending at the cable edges can be reduced, and the critical current can be steadily improved during testing. This suggests that lay pitch consistency control is directly related to performance consistency. Summary of the Invention

[0005] The purpose of this invention is to provide a stranding control method, system and device for zero-defect superconducting wires, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for controlling the stranding of a zero-defect superconducting wire is provided, the method comprising the following steps:

[0007] Obtain the strand twist pitch value of the superconducting strands to be stranded; Obtain the actual values ​​of the traction line speed and the actual values ​​of the stranding speed during the stranding process; The actual value of the cable lay length is determined based on the ratio of the actual value of the traction line speed to the actual value of the stranding speed. The twist pitch consistency ratio is determined based on the ratio of the actual cable twist pitch to the strand twist pitch. Find the integer closest to the pitch consistency ratio as the target integer for multiple consistency, and take the absolute value of the difference between the pitch consistency ratio and the target integer for multiple consistency as the multiple consistency deviation. When the deviation of the multiple consistency is greater than the multiple consistency tolerance limit, the stranding speed and / or traction speed are controlled so that the value of the cable lay is close to the value of the product of the multiple consistency target integer and the strand twist pitch value.

[0008] Furthermore, it may also include: The target cable twist pitch is determined based on the target integer of the multiple consistency and the strand twist pitch value, wherein the target cable twist pitch is the product of the target integer of the multiple consistency and the strand twist pitch value; and the cable twist pitch is controlled to approach the target cable twist pitch based on the target cable twist pitch; wherein the target integer of the multiple consistency is obtained by rounding the twist pitch consistency ratio.

[0009] In the past, cable lay length in superconducting cable manufacturing processes was often determined based on experience or offline testing. However, cabling introduces geometric degradation and filament damage, and the lay length and transpose angle themselves can contribute to this degradation. Common engineering estimates of geometric degradation, such as approximately 5%, make it difficult to standardize and reuse the selection of the most suitable lay length. The technical solution described in this invention explicitly defines the target cable lay length as a multiple of the target integer consistency multiplied by the strand twist pitch value. It further specifies that the target integer is obtained by rounding the lay length consistency ratio, thus reducing the integer multiple consistency from a control objective to a directly executable target lay length setting rule. By establishing a one-to-one integer multiple relationship between the target lay length and the strand twist pitch, this invention forms a reusable and portable setting rule, reducing trial-and-error and batch-to-batch differences in lay length selection, and providing a consistent target benchmark for subsequent online control. Essentially, it solidifies the mechanism of improving the consistency of critical current, namely the repeated damage and reduced current transfer of the same set of filaments at the edge bend, into a calculable rule that combines the target twist pitch with integer and strand pitch, thereby avoiding control target drift due to uncertainty of the target integer.

[0010] Furthermore, obtaining the actual values ​​of the traction line speed and the actual values ​​of the stranding speed may include: Multiple sets of traction line speed and stranding speed data are acquired within the same sampling window, and the average traction line speed and average stranding speed within the sampling window are calculated respectively. These are used as the actual values ​​of the traction line speed and stranding speed to calculate the consistency ratio between the actual value of the cable lay and the lay pitch.

[0011] In the stranding process, speed and rotation speed signals typically exhibit instantaneous fluctuations and measurement noise. Directly using instantaneous values ​​to calculate the lay length and deviation can easily lead to frequent false triggers and jittery control adjustments, resulting in additional mechanical disturbances. This is detrimental to the already deformation-sensitive nature of superconducting cables, particularly to performance degradation caused by edge bending and width-direction bending. This invention uses multiple samplings within a sampling window to obtain the actual values ​​of the traction line speed and stranding rotation speed, which are then used to determine the ratio of the actual cable lay length to the lay length consistency.

[0012] The technical solution described in this invention utilizes the average of the sampling window to improve the stability of pitch estimation, reduce the probability of false triggering, and make adjustment smoother. Combined with amplitude or speed limiting constraints, this helps reduce unnecessary transient shocks and improve process consistency and traceability. Specifically, the average of the sampling window is equivalent to low-pass filtering the speed or rotational speed signal, suppressing the chain-like amplification effect of transient disturbances on the pitch, ratio, and deviation, thereby reducing the controller's over-response to noise and achieving improved noise immunity and steady-state performance in control theory.

[0013] Further, preferably, when the deviation of the multiple consistency is greater than the multiple consistency tolerance limit, the control of the stranding speed and / or the traction line speed includes at least one of the following: While keeping the actual value of the traction line speed constant, the stranding speed setting value is set to the actual value of the traction line speed divided by the target cable twist pitch; While keeping the actual stranding speed constant, the traction speed setting is set to the actual stranding speed multiplied by the target cable lay length.

[0014] Furthermore, the multiple consistency tolerance limit is determined based on the specifications of the superconducting wire to be stranded. The specifications include at least one or more of the following: outer diameter of the wire bundle, number of strands, and / or cross-sectional area of ​​a single strand. The multiple consistency tolerance limit can be an upper limit deviation calculated from the specifications for triggering the execution of the control stranding speed and / or traction wire speed.

[0015] Furthermore, when the deviation of the multiple consistency is greater than the multiple consistency tolerance limit, a multiple consistency deviation (e.g., the multiple consistency deviation is greater than the multiple consistency tolerance limit) event is generated, and at least the following data associated with the event are recorded: strand twist pitch value, actual cable lay pitch value, lay pitch consistency ratio, multiple consistency target integer, multiple consistency deviation, and the corresponding actual values ​​of traction line speed and stranding speed, for traceability when checking for zero defects.

[0016] Further preferably, when the deviation of the multiple consistency is restored from being greater than the multiple consistency tolerance limit to being no greater than the multiple consistency tolerance limit, the stranding speed and / or traction line speed are controlled to be restored to the stranding speed setting value and / or traction line speed setting value before the deviation is triggered.

[0017] Furthermore, preferably, the adjustment of the stranding speed and / or traction line speed is subject to amplitude limiting and / or speed limiting constraints to limit the change in the set value of the stranding speed and / or traction line speed within adjacent control cycles, so as not to exceed the preset or automatically generated upper limit value.

[0018] Furthermore, the multiple consistency tolerance limit can be automatically calculated by the controller based on the outer diameter of the wire harness, the number of strands, and the cross-sectional area of ​​a single strand. Specifically, the ratio of the square of the outer diameter of the wire harness to the product of the square of the number of strands and the cross-sectional area of ​​a single strand can be determined as the multiple consistency tolerance limit.

[0019] The previous practice of using fixed thresholds and fixed tolerance limits is difficult to adapt to different specifications of superconducting wire harnesses simultaneously. Specification changes significantly alter the dimensions and complexity of the cable structure. Fixed thresholds may lead to frequent triggering when small specifications are sensitive, and delayed triggering when large specifications are less sensitive, which is detrimental to establishing a stable process window across specifications. The industry also generally emphasizes that the lay length is a crucial quantity in cable production, and its changes affect macroscopic mechanical properties such as flexibility and stress distribution. The method described in this invention changes the multiple consistency tolerance limit from a manually set threshold to one automatically calculated from specification parameters. The tolerance limit is determined by the harness outer diameter, number of strands, and cross-sectional area of ​​a single strand, without introducing any preset constants. By automatically calculating the tolerance limit through specification parameters, adaptive trigger sensitivity is achieved for products with different outer diameters, numbers of strands, and cross-sectional areas: the more complex the specification (e.g., more strands, larger cross-sectional area per strand), the tighter the tolerance limit automatically; the larger the specification (e.g., larger outer diameter), the wider the tolerance limit automatically. This maintains more consistent quality control across different product families, reduces manual parameter tuning, and improves reproducibility. This method maps structural complexity and tightness to the degree of tolerance tightening: an increase in the number of strands and cross-sectional area usually means that the stress and structural coupling related to contact, transposition, and edge bending per unit length are more sensitive, requiring earlier correction; an increase in outer diameter corresponds to an overall dimensional change, allowing for a relatively larger space for process fluctuations. At the same time, the relationship between lay length and mechanical stress is a fundamental law of cable making. For example, a shorter lay length usually results in tighter cabling and more concentrated local stress, while a longer lay length results in more flexible cabling. Adaptive tolerance limit can reduce the accumulation of performance risks caused by deviations leading to abnormal stress.

[0020] In the past, superconducting strand cabling, especially Rutherford type, has generally suffered from a degradation of the critical current relative to the sum of the un-cabled strands after cabling. This degradation stems from geometrical transposition and twist pitch, as well as from actual damage and work hardening caused to the filaments during cabling and compaction. These deformations are often more severe at the cable edges, leading to a decrease in the cable's critical current and stability. This invention, however, simultaneously acquires the strand twist pitch, actual traction speed, and actual stranding speed during the stranding process. Based on this, the actual cable twist pitch is determined, and a twist pitch consistency ratio of the cable twist pitch to the strand twist pitch is constructed. This ratio is rounded to obtain a target integer for consistency, and the deviation of the ratio from the target integer is used as a trigger. In the automated production process of power cables and cable accessories, when the deviation exceeds the consistency tolerance limit, the stranding speed and / or traction speed are adjusted in real time to make the cable twist pitch approach the target integer × strand twist pitch.

[0021] The technical solution described in this invention uses the consistency of the cable lay length and strand twist pitch as an integer multiple of each other as an online control target. This allows for timely identification and correction of lay length drift during production, ensuring that the damaged filaments at periodic bends in the cable's edges remain consistent. This suppresses the decrease in voltage and apparent critical current caused by current redistribution among the filaments. This consistency approach can stably improve the critical current by approximately 10% during testing, and the method is easy to apply. Specifically, at cable edge bends, filament degradation is not uniformly distributed. If the degraded filament groups at adjacent bends are inconsistent, current redistribution through current transfer between filaments in the matrix material is required, which generates additional voltage and reduces the overall critical current of the cable. However, when the cable lay length and strand twist pitch are consistent, the same group of filaments is repeatedly damaged at each bend, reducing current transfer and fully utilizing the characteristics of the critical current for stranding control of zero-defect superconducting wires.

[0022] This invention also provides a stranding control system for a zero-defect superconducting wire. The zero-defect superconducting wire stranding control system includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the stranding control method for the zero-defect superconducting wire. The zero-defect superconducting wire stranding control system can run on computing devices such as desktop computers, laptops, handheld computers, and cloud data centers. The runnable system may include, but is not limited to, processors, memory, and server clusters. The processor executes the computer program within the following system units: The data acquisition unit is used to acquire the strand twist pitch value of the superconducting strands to be stranded; and to acquire the actual value of the traction line speed and the actual value of the stranding speed during the stranding process. The data processing unit is used to determine the actual value of the cable lay length based on the actual value of the traction line speed and the actual value of the stranding speed; and to determine the lay length consistency ratio based on the actual value of the cable lay length and the strand twist pitch value. The deviation calculation unit is used to find the integer closest to the pitch consistency ratio as the multiple consistency target integer, and to take the absolute value of the difference between the pitch consistency ratio and the multiple consistency target integer as the multiple consistency deviation amount. An automatic control unit is used to control the stranding speed and / or traction speed so that the cable lay length approaches the combination of the target integer of the multiple consistency and the strand twist pitch value when the deviation of the multiple consistency is greater than the multiple consistency tolerance limit.

[0023] Correspondingly, the present invention also provides an electronic device, a readable storage medium, and a computer program product: An electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the stranding control method for a zero-defect superconducting wire and the method for each step thereof.

[0024] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to perform the stranding control method for a zero-defect superconducting wire and the method for each step thereof.

[0025] A computer program product includes a computer program that, when executed by a processor, implements the stranding control method for a zero-defect superconducting wire and the methods for each step thereof.

[0026] The beneficial effects of this invention are as follows: This invention provides a stranding control method, system, and device for zero-defect superconducting wires. The actual cable lay length is determined based on the actual value of the traction speed and the actual value of the stranding speed. A lay length consistency ratio is determined based on the actual cable lay length and the strand twist pitch value. The integer closest to the lay length consistency ratio is selected as the target integer for multiple consistency, and the absolute value of the difference between the lay length consistency ratio and the target integer for multiple consistency is taken as the multiple consistency deviation. When the multiple consistency deviation exceeds the multiple consistency tolerance limit, the stranding speed and / or traction speed are controlled to make the cable lay length approach the combination of the target integer for multiple consistency and the strand twist pitch value. This allows for timely identification, smooth correction, and process traceability of lay length multiple consistency deviations while meeting structural and mechanical process constraints, thereby improving product consistency and process controllability. Attached Figure Description

[0027] The above and other features of the present invention will become more apparent from the detailed description of the embodiments shown in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals denote the same or similar elements. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort. In the drawings: Figure 1 The diagram shows a flowchart of a stranding control method for zero-defect superconducting wire; Figure 2 The diagram shows the system structure of a stranding control system for a zero-defect superconducting wire. Detailed Implementation

[0028] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0029] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0030] like Figure 1 The diagram shown is a flowchart of a stranding control method for a zero-defect superconducting wire according to the present invention. The following is in conjunction with... Figure 1 This invention describes a method, system, and device for controlling the stranding of a zero-defect superconducting wire according to an embodiment of the present invention.

[0031] This invention proposes a stranding control method for zero-defect superconducting wires, the method specifically including the following steps: Obtain the strand twist pitch value of the superconducting strands to be stranded; obtain the actual value of the traction line speed and the actual value of the stranding speed during the stranding process; The actual value of the cable lay length is determined based on the actual value of the traction line speed and the actual value of the stranding speed; the lay length consistency ratio is determined based on the actual value of the cable lay length and the strand twist pitch value. Find the integer closest to the pitch consistency ratio as the target integer for multiple consistency, and take the absolute value of the difference between the pitch consistency ratio and the target integer for multiple consistency as the multiple consistency deviation. When the deviation of the multiple consistency is greater than the multiple consistency tolerance limit, the stranding speed or traction speed is controlled so that the cable lay length approaches the combination of the multiple consistency target integer and the strand twist pitch value.

[0032] Furthermore, among which: The target cable twist pitch is determined based on the target integer of the multiple consistency and the strand twist pitch value, wherein the target cable twist pitch is the product of the target integer of the multiple consistency and the strand twist pitch value; and the cable twist pitch is controlled to approach the target cable twist pitch based on the target cable twist pitch.

[0033] Furthermore, obtaining the actual values ​​of the traction line speed and the actual values ​​of the stranding speed includes: Multiple sets of traction line speed and stranding speed data are acquired within the same sampling window, and the average traction line speed and average stranding speed within the sampling window are calculated respectively. These are used as the actual values ​​of the traction line speed and stranding speed to calculate the consistency ratio between the actual value of the cable lay and the lay pitch.

[0034] Furthermore, when the deviation of the multiple consistency is greater than the multiple consistency tolerance limit, the control of the stranding speed and / or traction line speed includes at least one of the following: While keeping the actual value of the traction line speed constant, the stranding speed setting value is set to the actual value of the traction line speed divided by the target cable twist pitch; While keeping the actual stranding speed constant, the traction speed setting is set to the actual stranding speed multiplied by the target cable lay length.

[0035] Furthermore, the multiple consistency tolerance limit is determined based on the specifications of the superconducting wire to be stranded. The specifications include at least one of the following: outer diameter of the wire bundle, number of strands, and cross-sectional area of ​​a single strand. The multiple consistency tolerance limit is an upper limit calculated from the specifications for triggering the control of the stranding speed and / or the traction speed.

[0036] Furthermore, when the deviation of the multiple consistency exceeds the multiple consistency tolerance limit, an event record of the multiple consistency deviation is generated, and the data associated with the event is recorded for traceability.

[0037] Furthermore, when the deviation of the multiple consistency is restored from being greater than the multiple consistency tolerance limit to being no greater than the multiple consistency tolerance limit, the stranding speed and / or traction line speed are controlled to be restored to the stranding speed setting value and / or traction line speed setting value before the deviation is triggered.

[0038] Furthermore, the adjustment of the stranding speed and / or traction line speed is subject to amplitude limiting and / or speed limiting constraints to limit the change in the set value within adjacent control cycles to not exceed the upper limit value.

[0039] Furthermore, the multiple consistency tolerance limit is automatically calculated by the controller based on the outer diameter of the wire harness, the number of strands, and the cross-sectional area of ​​a single strand. Specifically, the ratio of the square of the outer diameter of the wire harness to the product of the square of the number of strands and the cross-sectional area of ​​a single strand is determined as the multiple consistency tolerance limit.

[0040] In embodiments of the present invention, the strand twist pitch value refers to the axial length corresponding to the completion of one full turn (360°) of the internal filaments (or equivalent structures) of the superconducting strand relative to the strand axis; optionally, this pitch can be measured by the untwisting method and used as a reference pitch value for the multiple consistency target. The actual value of the traction line speed refers to the statistical value, such as the average value, of the axial running speed generated by the traction / reeling device on the product within the sampling window; it is used to characterize the current advance speed of the production line and to determine the actual value of the cable twist pitch. The actual value of the stranding speed refers to the statistical value, such as the average value, of the rotational speed of the stranding actuator, such as the winch / spindle, within the sampling window; it is used to characterize the current stranding rotation state and to determine the actual value of the cable twist pitch.

[0041] In some embodiments, the actual cable lay length refers to the cable lay length value determined based on the actual traction speed and the actual stranding speed; wherein the lay length is used to characterize the axial length corresponding to each complete helical rotation (360°) of the cabling unit; it is used to characterize the lay length result of the current stranding state and to form the lay length consistency ratio. The lay length consistency ratio is the ratio of the actual cable lay length to the strand twist pitch value, used to characterize the degree of consistency between the cable lay length and the strand twist pitch. The target integer for consistency refers to the integer value obtained by rounding the lay length consistency ratio according to a specified rounding rule (e.g., rounding); it is used as a multiple factor for the target cable lay length. The deviation from consistency is the absolute value of the difference between the lay length consistency ratio and the target integer for consistency; it characterizes the degree of deviation of the current state from integer multiple consistency and is used to compare with the consistency tolerance limit to trigger adjustment. The consistency tolerance limit is the upper limit value to which the deviation from consistency is allowed; it is used to determine whether to trigger an adjustment to the stranding speed and / or traction speed.

[0042] In some embodiments, the target cable lay length refers to the target lay length determined by a multiple-consistent target integer and the strand twist pitch value; it is used as the target value for lay length convergence control. The stranding speed setpoint refers to the target speed command value issued by the controller to the stranding actuator; it is used to guide the stranding speed adjustment so that the cable lay length converges to the target cable lay length. The traction line speed setpoint refers to the target line speed command value issued by the controller to the traction / recruitment device; it is used to guide the traction line speed adjustment so that the cable lay length converges to the target cable lay length. The sampling window refers to a continuous sampling time period or set of sampling points used to acquire multiple sets of traction line speeds and stranding speeds and form statistical values ​​(e.g., average values); it is used to reduce the impact of instantaneous fluctuations on the calculation of actual values. The control cycle refers to the minimum time period in which the controller performs one sampling, calculation, and setpoint update; it is used to limit the calculation scope of the setpoint change within adjacent control cycles. Amplitude limiting and / or speed limiting constraints refer to setting an upper limit on the change in the stranding speed setting value and / or traction line speed setting value within adjacent control cycles; used to reduce the possibility of transient impact on superconducting strands caused by sudden changes in setting values.

[0043] In some optional embodiments, the event of multiple consistency deviation refers to the event record generated when the multiple consistency deviation exceeds the multiple consistency tolerance limit. This event can be used to record key data at the trigger moment and support zero-defect traceability. The outer diameter of the wire harness refers to the outer diameter dimension of the superconducting wire harness to be stranded under specified measurement conditions. Optionally, the outer diameter of the wire harness can be measured according to the method specified in the enterprise standard or industry standard under conditions of room temperature, specified tension, or no external tension, and the average value can be taken at multiple positions along the length direction; it can be used as a specification parameter in the calculation of the multiple consistency tolerance limit. The number of strands refers to the number of superconducting strands constituting the superconducting wire harness to be stranded, and can be used as a specification parameter in the calculation of the multiple consistency tolerance limit. The cross-sectional area of ​​a single strand refers to the cross-sectional area of ​​a single superconducting strand; optionally, the cross-sectional area of ​​a single strand can be determined according to the measurement / calibration calibrator specified in the enterprise standard or industry standard, and it is used as a specification parameter in the calculation of the multiple consistency tolerance limit. Specification parameters refer to a set of parameters used to characterize the structural dimensions and composition of the superconducting wire to be stranded, including at least one of the following: bundle outer diameter, number of strands, and single-strand cross-sectional area; used to determine or calculate the multiple consistency tolerance limit. The calculation rule for the multiple consistency tolerance limit indicates that the multiple consistency tolerance limit is automatically calculated by the controller based on the bundle outer diameter, number of strands, and single-strand cross-sectional area. The bundle outer diameter and single-strand cross-sectional area use a consistent unit system to ensure that the obtained multiple consistency tolerance limit is dimensionless and can be compared with the multiple consistency deviation. Preferably, it is used to generate the multiple consistency tolerance limit without introducing a preset constant and to trigger control logic.

[0044] In Embodiment 1 of this invention, the stranding production of a batch of zero-defect superconducting wire is used as an example for illustration. The specifications of this batch of products are as follows: outer diameter of the wire harness is 8.0 mm, number of strands is 40, and cross-sectional area of ​​a single strand is 0.80 mm². The control cycle of the control system is set to 0.2 s, that is, the controller performs sampling, calculation, and setpoint update once every 0.2 s. To avoid transient impacts, in terms of speed and amplitude constraints, the change in the stranding speed setpoint within adjacent control cycles does not exceed its upper limit of 1 rpm, and the change in the traction line speed setpoint within adjacent control cycles does not exceed its upper limit of 0.10 m / min. For this specification of product, the multiple consistency tolerance limit is set to 0.02, which is used to determine whether the multiple consistency deviation triggers the adjustment of the stranding speed and / or traction line speed.

[0045] Before stranding begins, the control system first acquires the strand twist pitch value of the superconducting strands to be stranded. In this embodiment, the strand twist pitch value is 22.5 mm, which can be obtained from incoming material inspection records or calibration data provided by the supplier.

[0046] During the stranding process, the control system acquires the actual values ​​of the traction wire speed and the stranding speed. To improve resistance to fluctuations, this embodiment employs a sampling window method: multiple sets of traction wire speed and stranding speed data are acquired within the same sampling window, and the average traction wire speed and stranding speed within the sampling window are calculated as the actual values. In this embodiment, the sampling window is 1.0 s, and a total of 5 sets of data are collected within this 1.0 s: traction wire speed 3.58 m / min, stranding speed 82 rpm; traction wire speed 3.61 m / min, stranding speed 83 rpm; traction wire speed 3.60 m / min, stranding speed 84 rpm; traction wire speed 3.62 m / min, stranding speed 83 rpm; traction wire speed 3.59 m / min, stranding speed 82 rpm. After averaging the above 5 sets of data, the actual value of the traction wire speed is obtained as 3.60 m / min, and the actual value of the stranding speed is 82.8 rpm.

[0047] After obtaining the actual values ​​of the traction speed and stranding speed, the control system determines the actual value of the cable lay. For ease of calculation, this embodiment converts the traction speed of 3.60 m / min to 3600 mm / min, and combines it with the stranding speed of 82.8 rpm to obtain the corresponding actual cable lay value of approximately 43.478 mm.

[0048] Subsequently, the control system determines the twist pitch consistency ratio based on the actual cable lay length and the strand twist pitch. In this embodiment, the actual cable lay length is approximately 43.478 mm, and the strand twist pitch is 22.5 mm, resulting in a twist pitch consistency ratio of approximately 1.93237.

[0049] The control system further rounds the pitch consistency ratio to obtain a target integer for the multiple consistency. In this embodiment, 1.93237 is rounded to the nearest integer, resulting in a target integer of 2. Subsequently, the control system uses the absolute value of the difference between the pitch consistency ratio and the target integer as the multiple consistency deviation. In this embodiment, the multiple consistency deviation is approximately 0.06763.

[0050] The control system compares the deviation from the multiple consistency tolerance limit to determine whether to trigger an adjustment. In this embodiment, the deviation from the multiple consistency limit is approximately 0.06763, and the tolerance limit is 0.02. Because the deviation from the multiple consistency limit is greater than the tolerance limit, the control system determines that an adjustment to the stranding speed and / or traction speed needs to be triggered to make the cable lay length approach the product of the target integer multiple consistency value and the strand twist pitch value. For example, the actual cable lay length of 43.478 mm can be increased in several increments, such as by 0.1 mm each time until the target cable lay length of 45.0 mm, or by 44.978 mm; or by 0.001 mm each time until the target cable lay length of 45 mm.

[0051] After the adjustment is triggered, the control system determines the target cable lay length based on the target integer of the multiple consistency target and the strand twist pitch value. In this embodiment, the target integer of the multiple consistency is 2, and the strand twist pitch value is 22.5 mm, thus obtaining a target cable lay length of 45.0 mm. Subsequently, the control system performs a setpoint calculation based on the target cable lay length and adjusts the stranding speed and / or traction line speed accordingly.

[0052] This embodiment employs a control method that maintains a constant traction line speed while adjusting the stranding speed. Specifically, while keeping the actual traction line speed constant at 3.60 m / min, the control system, combined with the target cable lay length of 45.0 mm, determines the stranding speed setpoint to be 80.0 rpm. Because this embodiment incorporates speed and amplitude limits, the change in the stranding speed setpoint within adjacent control cycles does not exceed 1 rpm. Since the actual stranding speed at the time of adjustment is approximately 82.8 rpm, the control system gradually lowers the stranding speed setpoint over three control cycles, issuing it sequentially as 81.8 rpm, 80.8 rpm, and 80.0 rpm. This reduces the possibility of rapid setpoint changes causing transient shocks to the superconducting strands.

[0053] After the above settings are adjusted, the control system acquires the traction line speed and stranding speed again in the next sampling window and calculates the deviation to determine whether it has returned to the tolerance limit. In this embodiment, the actual value of the traction line speed in the retest sampling window remains at 3.60 m / min, and the actual value of the stranding speed is 80.2 rpm. Based on this, the control system determines that the actual value of the cable lay is approximately 44.8878 mm, and further determines that the lay consistency ratio is approximately 1.99501; using the same rounding method as mentioned above, the target integer for the multiple consistency is still 2, and the corresponding multiple consistency deviation is approximately 0.00499. Since this multiple consistency deviation is no greater than the multiple consistency tolerance limit of 0.02, the control system determines that the deviation has returned to the tolerance limit.

[0054] When the deviation from the multiple consistency tolerance limit recovers to a value no greater than the multiple consistency tolerance limit, the control system restores the stranding speed and / or traction speed to the set values ​​before the deviation was triggered. In this embodiment, the target setting before the deviation was triggered is the set value corresponding to the target cable lay length of 45.0 mm. Therefore, the control system maintains the stranding speed set value at 80.0 rpm and the traction speed set value at 3.60 m / min, thereby maintaining stable production while meeting the multiple consistency requirements.

[0055] In addition, in this embodiment, when the deviation from the multiple consistency tolerance limit exceeds the multiple consistency tolerance limit and triggers adjustment, the control system generates a multiple consistency deviation event and records the data associated with the event for zero-defect traceability. The recorded data includes at least: strand twist pitch value of 22.5 mm, actual cable lay length of approximately 43.478 mm, lay length consistency ratio of approximately 1.93237, multiple consistency target integer of 2, multiple consistency deviation of approximately 0.06763, and the corresponding actual traction line speed of 3.60 m / min and actual stranding speed of 82.8 rpm. Through the above records, the cause of the deviation trigger, the process status at the trigger time, and the effect of subsequent corrections can be traced and verified.

[0056] In Embodiment 2 of the present invention, the sampling window can be set to 0.1s to 2s, used to sample multiple sets of traction line speeds and stranding speeds within the same sampling window and take the average value, so as to reduce the impact of instantaneous fluctuations on the determination result of the actual value of cable lay. The control cycle can be set to 0.05s to 1s, and the controller can complete one sampling, calculation and set value update in each control cycle. The multiple consistency tolerance limit can be set to 0.005 to 0.05, used to determine whether the multiple consistency deviation triggers the adjustment of stranding speed and / or traction line speed; wherein, the multiple consistency tolerance limit can be selected or set in grades according to at least one of the outer diameter of the wire bundle, the number of strands, and the cross-sectional area of ​​a single strand of the superconducting wire to be stranded.

[0057] In Embodiment 3 of this invention, the multiple consistency tolerance limit can be automatically calculated by the controller based on the specifications of the superconducting wire to be stranded. These specifications include the outer diameter of the wire harness, the number of strands, and the cross-sectional area of ​​a single strand. The controller can determine the multiple consistency tolerance limit as the ratio of the square of the outer diameter of the wire harness to the product of the square of the number of strands and the cross-sectional area of ​​a single strand. The outer diameter of the wire harness and the cross-sectional area of ​​a single strand use a consistent unit system, making the calculated multiple consistency tolerance limit dimensionless. For example, when the outer diameter of the wire harness is 8.0 mm, the number of strands is 40, and the cross-sectional area of ​​a single strand is 0.80 mm², the controller calculates a multiple consistency tolerance limit of 0.05 according to the above rules. During stranding, when the calculated multiple consistency deviation is greater than 0.05, an adjustment to the stranding speed and / or traction speed is triggered. When the multiple consistency deviation returns to no greater than 0.05, the controller returns to the set value before the deviation trigger and records the multiple consistency deviation event for traceability. Preferably, the outer diameter of the wire harness and the cross-sectional area of ​​a single strand can use a consistent unit of measurement system, such as the outer diameter in mm and the cross-sectional area in mm², so that the ratio can be a dimensionless quantity, which is convenient for comparison with the deviation of the multiple.

[0058] In summary, the stranding control method provided by the technical solution of this invention obtains the strand twist pitch value, the actual value of the traction line speed, and the actual value of the stranding speed during the stranding process, and determines the actual value of the cable lay pitch accordingly. Furthermore, it determines the lay pitch consistency ratio by comparing the actual cable lay pitch value with the strand twist pitch value, and rounds it to obtain a target integer multiple for consistency. This triggers the adjustment of the stranding speed and / or traction line speed when the deviation from the multiple consistency tolerance limit exceeds the multiple consistency tolerance limit, causing the cable lay pitch to converge towards the target cable lay pitch. Simultaneously, it uses amplitude limiting and / or... Alternatively, speed limits restrict the change in setpoint within adjacent control cycles, and restore the setpoint to the pre-trigger value after the deviation recovers to the tolerance limit, thus maintaining the continuity and traceability of the control process. Furthermore, by generating multiple consistency deviation events and recording the strand twist pitch value, actual cable lay pitch value, lay pitch consistency ratio, multiple consistency target integer, multiple consistency deviation amount, and the corresponding actual values ​​of traction line speed and stranding speed, the recording and traceability of deviation triggering and correction processes in the automatic control of the production process of power cables and cable accessories are achieved.

[0059] The stranding control system for a zero-defect superconducting wire operates on any computing device, such as a desktop computer, laptop computer, handheld computer, or cloud data center. The computing device includes a processor, a memory, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps in the stranding control method for the zero-defect superconducting wire. The operable system may include, but is not limited to, a processor, a memory, and a server cluster.

[0060] An embodiment of the present invention provides a stranding control system for a zero-defect superconducting wire, such as... Figure 2 As shown, a stranding control system for a zero-defect superconducting wire according to this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the above-described embodiment of a stranding control method for a zero-defect superconducting wire. The processor executes the computer program within the following system unit: The data acquisition unit is used to acquire the strand twist pitch value of the superconducting strands to be stranded; and to acquire the actual value of the traction line speed and the actual value of the stranding speed during the stranding process. The data processing unit is used to determine the actual value of the cable lay length based on the actual value of the traction line speed and the actual value of the stranding speed; and to determine the lay length consistency ratio based on the actual value of the cable lay length and the strand twist pitch value. The deviation calculation unit is used to find the integer closest to the pitch consistency ratio as the multiple consistency target integer, and to take the absolute value of the difference between the pitch consistency ratio and the multiple consistency target integer as the multiple consistency deviation amount. An automatic control unit is used to control the stranding speed and / or traction speed so that the cable lay length approaches the combination of the target integer of the multiple consistency and the strand twist pitch value when the deviation of the multiple consistency is greater than the multiple consistency tolerance limit.

[0061] In order to better unify the linear relationship and probabilistic connection between physical quantities with different units of measurement, dimensionless processing can be performed on different physical quantities.

[0062] Preferably, all undefined variables in this invention, if not explicitly defined, can be manually set thresholds.

[0063] The stranding control system for a zero-defect superconducting wire described above can operate in computing devices such as desktop computers, laptops, handheld computers, and cloud data centers. The stranding control system for a zero-defect superconducting wire includes, but is not limited to, a processor and a memory. Those skilled in the art will understand that the examples described are merely illustrations of a stranding control method, system, and device for a zero-defect superconducting wire, and do not constitute a limitation on such a method, system, and device. It may include more or fewer components, or a combination of certain components, or different components. For example, the stranding control system for a zero-defect superconducting wire may also include input / output devices, network access devices, buses, etc.

[0064] The present invention also provides an electronic device, a readable storage medium, and a computer program product: An electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the stranding control method for a zero-defect superconducting wire and the method for each step thereof.

[0065] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to perform the stranding control method for a zero-defect superconducting wire and the method for each step thereof.

[0066] A computer program product includes a computer program that, when executed by a processor, implements the stranding control method for a zero-defect superconducting wire and the methods for each step thereof.

[0067] The term "electronic device" is intended to refer to various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also refer to various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0068] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0069] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0070] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0071] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0072] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with embodiments of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0073] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other.

[0074] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete component gate circuits, transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the stranding control system for the zero-defect superconducting wire, connecting various sub-regions of the system via various interfaces and lines.

[0075] The memory can be used to store the computer program and / or modules. The processor implements various functions of the stranding control method, system, and device for zero-defect superconducting wire by running or executing the computer program and / or modules stored in the memory and calling the data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, phonebook, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0076] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0077] This invention provides a stranding control method, system, and device for zero-defect superconducting wire. The method involves determining the actual cable lay length based on the actual values ​​of the traction speed and stranding rotation speed; determining the lay length consistency ratio based on the actual lay length and the strand twist pitch; selecting the integer closest to the lay length consistency ratio as the target integer for multiple consistency; and using the absolute value of the difference between the lay length consistency ratio and the target integer for multiple consistency as the multiple consistency deviation; when the multiple consistency deviation exceeds the multiple consistency tolerance limit, controlling the stranding rotation speed and / or traction speed to make the cable lay length approach the combination of the target integer for multiple consistency and the strand twist pitch. This method achieves timely identification, smooth correction, and process traceability of lay length multiple consistency deviations while meeting structural and mechanical process constraints, thereby improving product consistency and process controllability.

[0078] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method of twist control of a zero-defect superconducting wire, characterized by, The method includes: Obtain the strand twist pitch value of the superconducting strands to be stranded; obtain the actual value of the traction line speed and the actual value of the stranding speed during the stranding process; The actual value of the cable lay length is determined based on the actual value of the traction line speed and the actual value of the stranding speed; the lay length consistency ratio is determined based on the actual value of the cable lay length and the strand twist pitch value. Find the integer closest to the pitch consistency ratio as the target integer for multiple consistency, and take the absolute value of the difference between the pitch consistency ratio and the target integer for multiple consistency as the multiple consistency deviation. When the deviation of the multiple consistency exceeds the multiple consistency tolerance limit, the stranding speed and / or traction speed are controlled to make the cable lay length approach the target cable lay length. The target cable lay length is determined based on the target integer of the multiple consistency and the strand twist pitch value. The target cable lay length is the product of the target integer of the multiple consistency and the strand twist pitch value. The multiple consistency tolerance limit is determined based on the specification parameters of the superconducting wire to be stranded. The specification parameters include at least one of the following: wire bundle outer diameter, number of strands, and single strand cross-sectional area. The multiple consistency tolerance limit is the upper limit value calculated from the specification parameters used to trigger the control of the stranding speed and / or traction speed.

2. A kind of zero-defect superconducting wire stranding control method according to claim 1, characterized by, in, Obtain the actual values ​​of the traction line speed and the actual values ​​of the stranding speed, including: Multiple sets of traction line speed and stranding speed data are acquired within the same sampling window, and the average traction line speed and average stranding speed within the sampling window are calculated respectively. These are used as the actual values ​​of the traction line speed and stranding speed to calculate the consistency ratio between the actual value of the cable lay and the lay pitch.

3. A method of twist control of a zero-defect superconducting wire according to claim 1, characterized by, When the deviation of the multiple consistency is greater than the multiple consistency tolerance limit, the control of the stranding speed and / or traction line speed includes at least one of the following: While keeping the actual value of the traction line speed constant, the stranding speed setting value is set to the actual value of the traction line speed divided by the target cable twist pitch; While keeping the actual stranding speed constant, the traction speed setting is set to the actual stranding speed multiplied by the target cable lay length.

4. The kind of a zero-defect superconducting wire's stranding control method according to claim 1, characterized in that, When the deviation of the multiple consistency exceeds the multiple consistency tolerance limit, an event record of the multiple consistency deviation is generated, and the data associated with the event is recorded for traceability.

5. The stranding control method for a zero-defect superconducting wire according to claim 1, characterized in that, When the deviation of the multiple consistency is restored from being greater than the multiple consistency tolerance limit to being no greater than the multiple consistency tolerance limit, the stranding speed and / or traction line speed are controlled to be restored to the stranding speed setting value and / or traction line speed setting value before the deviation is triggered. The setting value before the deviation is triggered is the setting value corresponding to the target cable lay length.

6. The stranding control method for a zero-defect superconducting wire according to claim 1, characterized in that, The adjustment of the stranding speed and / or traction line speed is subject to amplitude limiting and / or speed limiting constraints to limit the change of the set value within adjacent control cycles to not exceed the upper limit value.

7. The stranding control method for a zero-defect superconducting wire according to claim 1, characterized in that, The multiple consistency tolerance limit is automatically calculated by the controller based on the outer diameter of the wire harness, the number of strands, and the cross-sectional area of ​​a single strand. Specifically, the ratio of the square of the outer diameter of the wire harness to the product of the square of the number of strands and the cross-sectional area of ​​a single strand is determined as the multiple consistency tolerance limit.

8. A stranding control system for a zero-defect superconducting wire, characterized in that, The stranding control system for a zero-defect superconducting wire operates on any computing device, such as a desktop computer, a laptop computer, or a cloud data center. The computing device includes a processor, a memory, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the stranding control method for a zero-defect superconducting wire as described in any one of claims 1 to 7.

9. An electronic device, comprising: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores instructions executable by the at least one processor, characterized in that the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 7.

Images