Cable, aluminum extrusion equipment and seamless aluminum sheath forming process

Abstract

The invention discloses a cable, aluminum extrusion equipment and a forming process of a seamless aluminum sheath, and belongs to the technical field of cable manufacturing and metal extrusion forming, and the forming process comprises the following steps: S1, in a welding cavity with an isobaric ring belt and a logarithmic spiral rectifying groove, rectifying an aluminum flow from a shunting hole, and completing welding; s2, a shape follow-up flow channel and a phase change material cavity are formed in the near wall of the welding cavity, multi-point temperature and circumferential pressure data of a welding area are collected, and through cooperative control over heating and heat exchange, the change rate peak value of the temperature of the welding area along with time is not higher than 1 DEG C per second, and the circumferential pressure difference of the welding cavity is not higher than 1000 Pa; a real-time constraint window of the temperature change rate and the circumferential pressure difference is established in a welding cavity, so that the key process quantity can be measured and controlled and is directly linked with an upstream thermal boundary, stable forming without reducing the linear speed of a base line is realized, and the problems of untimely and inaccurate control caused by replacement by only using the surface temperature are solved.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing and metal extrusion forming technology, and more specifically, to the forming process of cables, aluminum extrusion equipment, and seamless aluminum sheaths. Background Technology

[0002] Seamless aluminum sheaths for power cables are typically produced by split-flow welding extrusion forming, followed by online shaping, functional chip installation, and non-metallic outer sheath covering and cooling. This type of continuous manufacturing process is simultaneously affected by the coupled influence of the thermal state of the welding zone, near-wall shear and flow field consistency, shaping cycle time, and cooling disturbances. In engineering, linear velocity, groove geometry, assembly spacing, and spray volume are often used as the main control variables, supplemented by imaging and infrared thermometry for correction and cooling. However, the coupling link between the transient thermodynamics of the welding zone and the downstream morphology is relatively long, and the process response is prone to lag and oscillation, making it difficult for the circumferential ripple amplitude and wall thickness variance to enter the stable window simultaneously without reducing speed.

[0003] Chinese Patent Publication No. CN115472343B discloses a high-voltage cable manufacturing process. The device chain includes corrugated aluminum sheath processing and welding, a slot forming fixture, a dual-camera device, temperature sensing, and cold water spraying, all coordinated and executed by a controller. This scheme first constructs processing parameters G based on user-input environmental parameters, determines the chip mounting spacing and slot width according to segmented thresholds, and then calculates transmission parameters P to set the initial linear velocity and initial spraying volume in segments. During the online stage, the lead amount Q is adjusted once or twice based on the surface infrared temperature and the splicing spacing identified by the camera to maintain assembly cycle time and cooling coordination.

[0004] However, several problems still exist in actual use, such as:

[0005] Its processing parameter G comes from environmental statistics rather than real-time process parameters of the production line, making it difficult to reflect key process states such as the temperature change rate of the welding zone and the circumferential pressure difference in a timely manner.

[0006] Furthermore, the temperature characterization mainly focuses on the surface temperature of the outer sheath, and no clear mechanism is found for setting the forming constraint window for the rate of change of temperature in the welding zone over time and the circumferential pressure difference in the welding cavity. Cooling disturbances are easily coupled with forming, leading to a trade-off between quality and energy consumption.

[0007] The visual measurements in the comparison documents mainly focus on the splicing spacing, and there is no evidence of mapping the downstream circumferential ripple phase and amplitude information to the upstream heating and heat exchange control quantities in real time. In use, the correction link for its morphological defects is relatively long and the process response is lagging.

[0008] The comparison file uses a discrete strategy with segmented thresholds and coefficient adjustments, which has limited ability to handle multivariate coupling and oscillation suppression, making it difficult to guarantee fast convergence and low oscillation operation while maintaining linear velocity. Summary of the Invention

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] The forming process of cables, aluminum extrusion equipment, and seamless aluminum sheaths includes the following steps:

[0011] S1, in the welding cavity with an equal pressure ring and logarithmic spiral rectifier groove, the aluminum flow from the diversion hole is rectified and welding is completed;

[0012] S2, a conformal flow channel and a phase change material cavity are set near the wall of the welding cavity, and multiple temperature and circumferential pressure data of the welding area are collected. Through the coordinated control of heating and heat exchange, the peak value of the temperature change rate of the welding area with time is not higher than 1℃ per second, and the circumferential pressure difference of the welding cavity is not higher than 1000Pa.

[0013] S3, online acquisition of the phase and fundamental frequency of the formed circumferential ripple, and synchronization with the linear velocity;

[0014] S4, based on the phase, perform reverse phase fine adjustment on the downstream segmented compliant shaping so that the roller speed modulation amplitude does not exceed 1% of the linear speed and the phase prediction error is not higher than 10°.

[0015] S5, establish a real-time mapping between the phase and the temperature change rate threshold of step 2, and trigger power fine-tuning of the phase change material cavity and conformal flow channel accordingly, so that ripple suppression and welding stability are satisfied at the same time, and the linear velocity is not lower than 90% of the baseline condition during the execution of S4 and S5;

[0016] S6 uses the weighted sum of the square of the eccentricity and the energy consumption per unit length as the auxiliary target for the climbing stage, and updates the weights online according to preset rules so that the eccentricity and the energy consumption per unit length decrease simultaneously to within the set threshold.

[0017] Furthermore, the real-time mapping in S5 satisfies the following constraints:

[0018] The real-time mapping is a monotonic relationship, which is achieved by piecewise linear interpolation or spline interpolation. The independent variables are the circumferential ripple phase obtained by S3 and the synchronous linear velocity. The output includes the following three adjustment items: the upper limit of the peak value of the rate of change of temperature over time, the power fine-tuning of the phase change material cavity, and the power fine-tuning of the conformal flow channel.

[0019] As the phase offset of the circumferential ripple increases, the upper limit of the peak value of the rate of change of temperature with time tightens according to a monotonically decreasing relationship, and the adjustment amount of the phase change material cavity power fine-tuning and the adjustment amount of the conformal flow channel power fine-tuning decrease synchronously.

[0020] When the shift of the circumferential ripple phase decreases, the upper limit of the peak value of the rate of change of temperature with time is relaxed in a monotonically increasing relationship. The adjustment amount of the phase change material cavity power fine-tuning and the adjustment amount of the conformal flow channel power fine-tuning are increased synchronously, and the relaxation amount each time does not exceed the corresponding tightening amount.

[0021] Each time the mapping is updated, the adjustment amount of the upper limit of the peak value of the rate of change of temperature over time is 5% to 50% of the previous setting; the adjustment amount of the phase change material cavity power fine-tuning is 5% to 50% of their respective previous settings, and is consistent with the adjustment direction of the upper limit of the peak value of the rate of change of temperature over time.

[0022] The adjustment amount of the conformal flow channel power fine-tuning is 5% to 50% of the previous setting value, and is consistent with the adjustment direction of the upper limit of the peak value of the temperature change rate over time.

[0023] The real-time mapping converges within two consecutive updates, and the update period is consistent with the control period.

[0024] Furthermore, during S1 and S2, the maximum difference in the circumferential pressure distribution of the welding cavity within the axial target section is controlled to be ≤1000Pa; at the same time, the volume distribution of each diverter and the inlet angle are matched according to the preset ratio, so that the standard deviation of the residence time before welding is ≤8%, and the range of the shear rate before welding is ≤10%.

[0025] Furthermore, the following sampling and control rules are executed during S1 and S2:

[0026] Temperature and pressure data at no less than 6 locations are collected synchronously in the circumferential direction of the welding cavity, with a sampling period of no more than 50ms. The timestamp and linear velocity encoding are synchronized, and the alignment error is no more than 10ms.

[0027] The rate of change of temperature over time was calculated using the central difference within a time window of 100ms to 200ms, and its peak value was defined as the maximum derivative within a 1s moving window.

[0028] The circumferential pressure difference is defined as the difference between the maximum and minimum values ​​of the circumferential pressure samples taken at the same time.

[0029] Each control cycle updates the phase change material cavity power fine-tuning and conformal flow channel power fine-tuning according to the feedforward plus integral control strategy. The control cycle is no more than 200ms, and the single update amplitude is no more than 10% of the rated power.

[0030] Within two consecutive control cycles, the two thresholds specified by S2 must be met simultaneously: the peak value of the rate of change of temperature over time ≤ 1℃ / s and the circumferential pressure difference of the welding cavity ≤ 1000Pa.

[0031] Furthermore, during the control processes of S2 and S5, the melting temperature range of the phase change material is set to cover ±5°C of the target welding temperature, with a latent heat per unit volume ranging from 180kJ per liter to 350kJ per liter.

[0032] The effective thermal conductivity near the wall of the welding cavity is adjusted by heat exchange through conformal flow channels, so that the ratio of the effective thermal conductivity near the wall to the effective thermal conductivity near the wall when the conformal flow channels are not opened is 1 to 3.

[0033] The phase change material cavity power fine-tuning adopts a quantization stepping method, with a single update stepping amplitude of 1% to 10% of the rated power and an update interval of no less than 2 sampling cycles;

[0034] When the linear velocity is maintained at no less than 90% of the baseline operating condition, the above interval and step rules continue to be executed.

[0035] Furthermore, the circumferential ripple phase obtained by S3 drives the fine-tuning of the shaping roller speed in S4, which is performed according to the following anti-vibration decoupling rules:

[0036] The roller speed modulation adopts a single-frequency or dual-frequency method, and the modulation period is an integer multiple of the control period, with the multiple not less than 3;

[0037] Each control cycle only updates the roller speed modulation parameters once. The update adopts quantization stepping, and the single update amplitude is no more than 1% of the linear speed. The phase prediction error is limited to 10°.

[0038] The roller speed modulation and the temperature change rate closed loop are decoupled from each other. The modulation period is kept as an integer multiple of the control period and not less than 3 times. The modulation phase and the circumferential ripple phase are out of phase.

[0039] When signs of coupled oscillation appear, self-recovery is performed: if the circumferential ripple amplitude does not decrease within two consecutive modulation cycles and the peak value of the rate of change of temperature over time is close to or greater than 80% of the threshold, the modulation cycle is increased to a higher integer multiple and the modulation amplitude is reduced by 20% to 50% until the circumferential ripple amplitude decreases and recovers to the stable window.

[0040] Furthermore, the following rules are executed in the joint objective optimization of S6:

[0041] The joint objective is the weighted sum of the square of the eccentricity and the energy consumption per unit length, with the sum of the two weights being 1, and the initial values ​​all falling between 0.2 and 0.8.

[0042] The update cycle is no more than 1 second, and the weight change in each update is no more than 0.05.

[0043] The moving average of the last three update cycles is used as the judgment criterion: when the eccentricity increases but the energy consumption per unit length does not decrease, the weight corresponding to the eccentricity is increased and the weight corresponding to the energy consumption is decreased by the same amount; when the energy consumption per unit length increases but the eccentricity does not decrease, the weight corresponding to the energy consumption is increased and the weight corresponding to the eccentricity is decreased by the same amount; when both increase simultaneously, the step size is halved; when both decrease simultaneously, the weights remain unchanged.

[0044] When the eccentricity and the moving average of energy consumption per unit length both fall within their respective set thresholds during a continuous 60-second run, the weight update is stopped; if either indicator exceeds the set threshold and remains so for 10 seconds, the weight update is restarted.

[0045] Furthermore, online micro-leakage detection and corrective action are implemented between S3 and S5, specifically including:

[0046] A differential suction and labeling gas concentration comparison method is adopted. Trace amount of labeling gas is introduced into the core of the sheath. The concentration ratio of the peripheral background and near-wall suction is calculated within a 1-second window. The timestamp and linear velocity encoding are synchronized, with an alignment error of no more than 10ms. If the concentration ratio exceeds the threshold, it is judged as a leak.

[0047] Leakage location is given by linear velocity and time for axial coordinates and by rotary encoder pulse count for circumferential coordinates. The location resolution is not less than 5 mm and the minimum detectable leakage rate reaches 10 to the power of -9 Pa·m³ / s.

[0048] When a leakage event occurs, within an axial window length of no more than 100 mm in the vicinity of the leakage coordinate, local reverse phase fine adjustment is performed on the segmented shaping of S4, the roller speed modulation amplitude does not exceed 1% of the linear speed, and the duration of a single local correction does not exceed 15 s.

[0049] When a leakage event is triggered, the peak limit of the temperature change rate of S2 over time is temporarily tightened, with the tightening range being 10% to 30% of the current setting. After the tightening ends, the setting is restored to the previous setting in equal steps.

[0050] The release condition is that the concentration ratio is updated twice consecutively to below 80% of the threshold, or the concentration ratio is not reduced after local correction for 10 seconds. In this case, the axial window is enlarged to twice the original value and an alarm is recorded. The linear velocity is kept at no less than 90% of the baseline condition.

[0051] In summary, the present invention has the following beneficial effects:

[0052] By establishing a real-time constraint window for the temperature change rate and circumferential pressure difference within the welding cavity, key process quantities can be measured and controlled and directly linked with the upstream thermal boundary, achieving stable forming without a decrease in baseline velocity and solving the problems of untimely and inaccurate control caused by relying solely on surface temperature.

[0053] By extracting the downstream circumferential ripple phase and amplitude online and mapping them to the control quantities of upstream heating and conformal heat transfer, the correction link is significantly shortened, realizing the convergent control of the thermal field by the morphology, and solving the problems of feedback hysteresis and easy oscillation in the traditional scheme.

[0054] By combining small-amplitude phase reversal shaping with visual prediction error constraints, the roller speed modulation is limited to within one percent of the online speed, achieving a smooth transition for ripple suppression and solving the defects of easy over-adjustment and secondary oscillation in segmented threshold parameter adjustment.

[0055] By employing a control strategy that combines monotonic mapping with convergence within two updates, the number of parameter optimization steps and rework cycles is significantly reduced, enabling rapid stabilization of the first piece and consistency across batches. This solves the problems of high cost and low efficiency in parameter tuning under multivariable coupling. Attached Figure Description

[0056] To more clearly illustrate the technical solutions 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.

[0057] Figure 1 This is a schematic diagram of the process flow of the present invention;

[0058] Figure 2 This is a schematic diagram of the real-time mapping monotonic segmentation and two-update internal convergence process in step S5 of the present invention.

[0059] Figure 3 This is a schematic diagram of the welding cavity equal pressure ring and consistency control of the present invention;

[0060] Figure 4 This is a schematic diagram of the anti-vibration decoupling and self-recovery timing diagram of the present invention. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] Example:

[0063] The following is in conjunction with the appendix Figure 1-4 The present invention will be described in further detail below.

[0064] Please see Figure 1-4 This invention provides a technical solution: a forming process for cables, aluminum extrusion equipment, and seamless aluminum sheaths, such as... Figure 1-4 As shown, it includes the following steps:

[0065] S1, in the welding cavity with an equal pressure ring and logarithmic spiral rectifier groove, the aluminum flow from the diversion hole is rectified and welding is completed;

[0066] S2, a conformal flow channel and a phase change material cavity are set near the wall of the welding cavity, and multiple temperature and circumferential pressure data of the welding area are collected. Through the coordinated control of heating and heat exchange, the peak value of the temperature change rate of the welding area with time is not higher than 1℃ per second, and the circumferential pressure difference of the welding cavity is not higher than 1000Pa.

[0067] S3, online acquisition of the phase and fundamental frequency of the formed circumferential ripple, and synchronization with the linear velocity;

[0068] S4, based on the phase, perform reverse phase fine adjustment on the downstream segmented compliant shaping so that the roller speed modulation amplitude does not exceed 1% of the linear speed and the phase prediction error is not higher than 10°.

[0069] S5, establish a real-time mapping between the phase and the temperature change rate threshold of step 2, and trigger power fine-tuning of the phase change material cavity and conformal flow channel accordingly, so that ripple suppression and welding stability are satisfied at the same time, and the linear velocity is not lower than 90% of the baseline condition during the execution of S4 and S5;

[0070] S6 uses the weighted sum of the square of the eccentricity and the energy consumption per unit length as the auxiliary target for the climbing stage, and updates the weights online according to preset rules so that the eccentricity and the energy consumption per unit length decrease to within the set threshold at the same time.

[0071] In this embodiment: the test object is the seamless aluminum sheath forming of a 35kV distribution cable, with a target outer diameter of 30mm and a nominal wall thickness of 2.5mm;

[0072] The aluminum billet is a 1050 grade round cast rod, which is homogenized before extrusion. The production line is a 2000t horizontal aluminum extrusion line with a split and welded die, and the constant temperature workshop is 23±2℃.

[0073] First, a baseline linear velocity V0 is established using conventional absolute temperature control and conventional shaping: after running stably for 5 minutes without enabling phase feedforward and mapping control, the average linear velocity is taken, resulting in V0 = 12.0 m / min.

[0074] To reduce the impact of environmental disturbances on the morphology phase, a windbreak curtain is installed in the forming outlet area and a constant exhaust is maintained.

[0075] During the flow splitting and welding stages, the inlet angle is finely adjusted through the pre-calibration function of "volume distribution and inlet angle" so that the target section of about 30mm axial direction of the welding section reaches the "equal pressure ring" state, which is defined as the maximum difference in circumferential pressure at the same time ΔPθ≤1000Pa;

[0076] The specific procedure is to first select the gear closest to isobaric among the three inlet angles, and then fine-tune it in 0.1° steps until ΔPθ converges.

[0077] Eight miniature thermocouples and eight micro-pressure sensors are arranged circumferentially in the welding area, with a sampling period of 50ms. The timestamp is synchronized with the linear speed encoder, and the alignment error is ≤10ms. The rate of temperature change over time adopts central difference with a time window of 100–200ms; within a 1s moving window, the maximum absolute value of the derivative at each circumferential point is taken as the peak rate of change.

[0078] Therefore, the control target is redefined from absolute temperature as "peak rate of change ≤ 1℃ / s and circumferential pressure difference ≤ 1000Pa", the actuator is the annular induction heating power and the heat exchange of the conformal flow channel, and the "feedforward + integral" control law is used, with a single-step update amplitude ≤ 10% of the rated power and a control cycle of 200ms.

[0079] The circumferential corrugation morphology of the formed surface was acquired synchronously by a linear array camera (4kHz) and a rotary encoder. One loop of data was interpolated to an equal angle grid (2048 points) using cubic splines. After Hanning window bandpass filtering, the fundamental frequency complex coefficient C1 was extracted, and its phase φ = arg(C1) (degrees).

[0080] The reference phase is taken from the predicted value of the previous control cycle, and the phase offset is calculated. Then take the absolute value |φ| to control the mapping;

[0081] The prediction error is limited to 10° to suppress outliers. Downstream shaping uses a 3-section compliant roller. The roller speed is fine-tuned by small amplitude modulation according to the principle of "opposite phase to the current ripple". The amplitude is ≤1% of the linear speed. The modulation period is an integer multiple of the control period and ≥3 times. It is stipulated that the modulation parameters are updated only once per control period to avoid coupling oscillation with the aforementioned thermal field closed loop.

[0082] To convert the downstream morphology signal into a direct control quantity of the upstream heat flow, a piecewise linear monotonic mapping is established with |φ| and linear velocity v as independent variables, outputting three terms:

[0083] Tightening / loosening of the target rate of change threshold L (°C / s);

[0084] Phase change material cavity power step ΔP pcm (Percentage of rated power)

[0085] conformal flow channel heat transfer step ΔQ flow (Percentage of rated heat exchange).

[0086] Example is labeled as:

[0087] When |φ|≤5°, L=1.0, ΔP pcm =5%, ΔQ flow =5%;

[0088] When 5° < |φ| ≤ 15°, L linearly tightens to 0.7, ΔP pcm With ΔQ flow Linearity increased to 10%;

[0089] When 15° < |φ| ≤ 25°, L decreases to 0.5, ΔP pcm With ΔQ flow Increased to 20%;

[0090] When 25° < |φ| ≤ 40°, L continues to decrease to approximately 0.45, ΔP pcm With ΔQ flow Increase to 30–40%;

[0091] When |φ|>40°, L≥0.4, and the step capping is 40%.

[0092] The single-step quantization constraint is 5%–50% of the previous set value, and convergence occurs within two updates. The update period is consistent with the control period.

[0093] The experiment maintained v≥0.9·V0, and in this example, the speed was kept constant at 12.0 m / min.

[0094] During the initial phase, the joint objective is set as J = w1·(eccentricity)^2 + w2·(energy consumption per unit length E), with initial w1 = w2 = 0.5, updated every 1 second, and single weight change ≤ 0.05.

[0095] The criterion is the moving average over the last three update periods:

[0096] If only one factor worsens, its corresponding weight is increased and the other weight is decreased by the same amount. If both factors rise simultaneously, the step size is halved. If both factors fall simultaneously, the weights are frozen.

[0097] If two indicators simultaneously reach the set threshold for 60 consecutive seconds, the update will stop. If either indicator exceeds the threshold for 10 seconds, the system will automatically restart.

[0098] To ensure a fair comparison, three sets of references are set up:

[0099] Reference A (absolute temperature control only), Comparison B (phase feedforward shaping only), Comparison C (speed reduction + shaping, linear speed reduced to 9.5m / min).

[0100] All four groups continuously produced ≥300m under the same outer diameter, wall thickness, material, and environmental conditions. The following parameters were recorded and statistically analyzed: circumferential ripple amplitude (μm, fundamental frequency peak / valley / 2), wall thickness variance (μm², 1s window), energy consumption per unit length (kWh / 1000m), eccentricity (%), peak temperature change rate (℃ / s), circumferential pressure difference (Pa), first-pass yield (%), rework rate (%), number of correction triggers (times / km), convergence time (s), weld strength retention rate (%, shear), and inclusion area ratio (%, metallographic).

[0101] Each value was averaged after three replicates, and the standard deviation was controlled within 10% of the mean. The experimental data are as follows:

[0102] Comparison of key performance indicators of different control strategies under the same linear velocity conditions (Table #1)

[0103]

[0104] As can be seen from the table, without reducing the linear speed (Invention D and benchmark A and comparison B are both 12.0 m / min, while comparison C is 9.5 m / min), Invention D achieves optimal linkage of multiple indicators, demonstrating the nonlinear composite effect brought about by the redefinition of control targets and strong cross-segment coupling mapping.

[0105] First, the circumferential ripple amplitude decreased from 120μm in reference A to 45μm, a reduction of 62.5%; compared with comparison B (90μm) which only performed phase feedforward, there was still a further improvement of 50%.

[0106] Even compared to the "slowing down and shaping" comparison C (65μm), invention D is still about 31% lower, without sacrificing productivity.

[0107] Wall thickness stability is also significant:

[0108] The wall thickness variance decreased from 210 μm² to 95 μm², which is 45% of the baseline. Although the variance of C decreased to 120 μm² due to the speed reduction, it resulted in a decrease in single-shift output from 5.76 km to 4.56 km. This shows that the traditional approach trades output for quality, while this embodiment achieves better morphology and stability at the same linear speed.

[0109] In terms of process controllability, the peak temperature change rate and circumferential pressure difference were 0.6℃ / s and 780Pa, respectively, which were significantly lower than the upper limit of the dual threshold and better than the three comparison groups.

[0110] The convergence time was shortened to 70s (180s for baseline A, 140s for comparison B, and 220s for deceleration C), indicating that the monotonic mapping of "phase → rate of change threshold → power step" converged within two updates, and was decoupled from the fine adjustment of the shaping roller through the principle of period integer multiple and phase reversal, thus avoiding closed-loop mutual interference and subharmonic oscillation.

[0111] The combined goals of energy efficiency and eccentricity also demonstrate advantages:

[0112] The energy consumption per unit length is 21.2 kWh / 1000m, which is lower than groups A, B and C;

[0113] The eccentricity rate dropped to 0.75%, which is 0.50, 0.35, and 0.10 percentage points lower than A, B, and C, respectively.

[0114] Compared to C, although the eccentricity reliably reduces the speed by 0.85%, the energy consumption increases to 24.5 kWh / 1000m, reflecting the traditional trade-off relationship;

[0115] This embodiment uses bounded adaptive weights during the ramp-up phase to ensure that energy consumption and eccentricity simultaneously reach the threshold, thus avoiding the deterioration of one indicator caused by the optimization of a single indicator.

[0116] In terms of quality consistency, the first-pass yield rate has increased to 99%, the rework rate is only 1.0%, and the number of correction triggers has been reduced to 0.8 times / km. This reflects the self-correction capability of "downstream defect signal triggering short-term thermal flow tightening and local reverse phase shaping", which transforms the defects previously detected offline into in-process locatable corrections.

[0117] At the metallurgical level, the weld strength retention rate increased to 97% and the inclusion area ratio decreased to 0.4%, indicating that within a window of lower temperature change rate and controlled circumferential pressure difference, the weld interface is denser and there are fewer oxide inclusions.

[0118] like Figure 1-4 As shown, the real-time mapping in S5 satisfies the following constraints:

[0119] The real-time mapping is a monotonic relationship, which is achieved by piecewise linear interpolation or spline interpolation. The independent variables are the circumferential ripple phase obtained by S3 and the synchronous linear velocity. The output includes the following three adjustment items: the upper limit of the peak value of the rate of change of temperature over time, the power fine-tuning of the phase change material cavity, and the power fine-tuning of the conformal flow channel.

[0120] As the phase offset of the circumferential ripple increases, the upper limit of the peak value of the rate of change of temperature with time tightens according to a monotonically decreasing relationship, and the adjustment amount of the phase change material cavity power fine-tuning and the adjustment amount of the conformal flow channel power fine-tuning decrease synchronously.

[0121] When the shift of the circumferential ripple phase decreases, the upper limit of the peak value of the rate of change of temperature with time is relaxed in a monotonically increasing relationship. The adjustment amount of the phase change material cavity power fine-tuning and the adjustment amount of the conformal flow channel power fine-tuning are increased synchronously, and the relaxation amount each time does not exceed the corresponding tightening amount.

[0122] Each time the mapping is updated, the adjustment amount of the upper limit of the peak value of the rate of change of temperature over time is 5% to 50% of the previous setting; the adjustment amount of the phase change material cavity power fine-tuning is 5% to 50% of their respective previous settings, and is consistent with the adjustment direction of the upper limit of the peak value of the rate of change of temperature over time.

[0123] The adjustment amount of the conformal flow channel power fine-tuning is 5% to 50% of the previous setting value, and is consistent with the adjustment direction of the upper limit of the peak value of the temperature change rate over time.

[0124] The real-time mapping converges within two consecutive updates, and the update period is consistent with the control period.

[0125] In this embodiment, the test object is the seamless aluminum sheath forming process of 35kV distribution cable.

[0126] The production line and materials are the same as in the previous example:

[0127] Outer diameter 30mm, nominal wall thickness 2.5mm, aluminum billet grade 1050, operating at a linear speed of around 12.0m / min and not less than 0.9·VO.

[0128] To establish and verify the real-time mapping of the phase-temperature change rate threshold-power step mentioned above, a three-stage test of calibration, on-machine testing, and comparison was conducted on the same line.

[0129] First, complete the data acquisition process:

[0130] The shaped surface is simultaneously sampled using a 4kHz linear scan camera and a 4096ppr rotary encoder.

[0131] After reconstructing the signal at 2048 degrees per revolution, a Hanning window bandpass filter is applied to obtain the circumferential signal s(θ).

[0132] Calculate the fundamental frequency complex coefficients C1, and take the phase φ = arg(C1) Reference phase ref Take the predicted value from the previous control cycle and wrap it to (-180°, 180°) to obtain the result. Then take the absolute value. As one of the mapping inputs.

[0133] Phase prediction error limiting If an outlier occurs, it is replaced with the predicted value ±10°.

[0134] Temperature and pressure in the welding zone are collected at 8 points circumferentially, with a sampling period of 50ms. Alignment error with linear velocity encoding is also considered. ms.

[0135] The rate of change of temperature over time was calculated using the central difference of a 100-200 ms window;

[0136] Within a 1-second moving window, the maximum absolute value of the derivative of all circumferential points is taken as the peak rate of change. .

[0137] The circumferential pressure difference ΔPθ is defined as the range of circumferential pressure at the same moment.

[0138] The above definitions and algorithms ensure that phase, rate of change, and pressure difference are all measurable, calculable, and verifiable.

[0139] The calibration process in v The process is carried out at a speed of m / min, by making small phase disturbances to the shaping rollers and fine-tuning the upstream inlet angle, covering... The four intervals:

[0140] 0-5°, 5-15°, 15-25°, 25-40° / 60°.

[0141] For each interval, can the minimum threshold L still be used to make Based on the principle that ΔPθ≤1000Pa and the ripple amplitude does not increase, the target threshold L (°C / s) for the rate of change is calibrated.

[0142] At the same time, the minimum power step combination that can satisfy the above constraints was measured: the phase change cavity power step ΔPpcm as a percentage of the rated power and the conformal flow channel heat transfer step ΔQflow as a percentage of the rated power.

[0143] For the monotonic and piecewise linear or spline interpolation mentioned above, the calibration points are fitted as piecewise linear mappings, and at runtime, 5%-50% single-step quantization and two update internal convergence constraints are applied to the three outputs respectively, with the update period being consistent with the control period (200ms).

[0144] The running mapping uses the following explicit formula (v can be used directly when it is between 11.5 and 12.5 m / min; if v deviates from this range, L can be tightened / loosened proportionally by a coefficient v / 12.0; ΔPpcm and ΔQflow remain unchanged):

[0145] Rate of change threshold target (°C / s):

[0146] ;

[0147] Phase change cavity power stepping, (Percentage of rated capacity):

[0148] ;

[0149] conformal flow channel heat exchange step, (Percentage of rated capacity);

[0150] Calculate the changes of the three objectives for each control cycle. Afterwards, respectively Perform single-step quantization

[0151] ;

[0152] Ensure that each step is 5%-50% consistent with the direction and monotony;

[0153] Within two updates after implementation, check whether the requirements are met. and .

[0154] If the condition is not met, an update will be performed in the same direction; if the condition is still not met after two consecutive updates, the failure protection will be triggered, specifically:

[0155] when Two consecutive cycles of rise and

[0156] Temporarily and Add 10% in this cycle, relative gain (without exceeding the 50% upper limit);

[0157] If the phase prediction error exceeds the limit (>10°) or the camera drops frames, the mapping is frozen, and only the S2 double threshold closed loop is retained until the vision is restored.

[0158] when For 1 second, forcibly tighten L to the upper limit of 0.4°C / s and then... , Set to a temporary value of 40% until Return to the window;

[0159] To demonstrate the necessity and superiority of monotonicity and quantization with double convergence, four strategies were compared under the same operating conditions: Mapping M - monotonic piecewise segmentation (this invention), Mapping N - constant threshold (no mapping), Mapping P - non-monotonic spline (incorrect direction), and Mapping Q - large step size without quantization. Each strategy was used for 300m (re-preheating and isobaricization during production changeover), and key processes and quality indicators were recorded. Specific parameters are as follows:

[0160] Comparison of mapping control strategy and two convergence / process quality indicators (Table #2)

[0161]

[0162] Mapping M stably satisfies the double threshold within two updates, while the constant threshold and non-monotonic spline cannot be reached within two updates, resulting in significantly higher ripple amplitude and wall thickness variance. Although large step size without quantization can reduce the rate of change relatively quickly, it causes coupled oscillations of temperature and pressure due to over-adjustment, which prolongs the convergence time and significantly increases the number of oscillation events.

[0163] While maintaining a linear velocity of 12.0 m / min, the mapping M reduced the ripple amplitude to 45 μm and the wall thickness variance to 95 μm², which is better than the other three groups; the first-pass yield of 99% and the lowest rework rate of 1.0% demonstrate the direct contribution of the mapping to the process stability.

[0164] In terms of energy consumption, the energy consumption per unit length of the mapping M is the lowest (21.2kWh / 1000m), indicating that monotonic mapping and 5%–50% quantization stepping avoid energy consumption fluctuations caused by excessive cooling / heating, and are a more economical path than "large stepping without quantization".

[0165] The comparison between constant threshold and non-monotonic spline corresponds precisely to the parameter optimization or arbitrary mapping approach commonly used in the review process. The data shows that without directionality and step window constraints, it is difficult to achieve convergence twice at the same linear velocity, and it is also difficult to achieve synchronous improvement of ripple and wall thickness, making it difficult to achieve the composite effect promised by this invention.

[0166] like Figure 1-4 As shown, during S1 and S2, the maximum difference in circumferential pressure distribution within the target axial section of the welding cavity is controlled to be ≤1000Pa; simultaneously, the volume distribution and inlet angle of each diverter are matched according to a preset ratio, so that the standard deviation of the residence time before welding is ≤8%, and the range of shear rate before welding is ≤10%.

[0167] In this embodiment, the object of implementation is the seamless aluminum sheath forming of a 35kV distribution cable, with a target outer diameter of 30mm and a nominal wall thickness of 2.5mm.

[0168] The aluminum billet uses 1050 grade round cast rods, and the extruder is a 2000t horizontal split-flow and welded production line.

[0169] The baseline linear velocity V0 was obtained by averaging the results after 5 minutes of stable operation under normal absolute temperature control and normal shaping without any isobaric or uniform control. The result was V0 = 12.0 m / min.

[0170] In this embodiment, the linear velocity is maintained at ≥0.9·V0 throughout the entire process, with an actual operating speed of 12.0 m / min. To achieve the operating condition constraints defined in claim 3, the following measurement and control link is established in the shunt-welding zone:

[0171] Eight micro-pressure sampling points P1…P8 are arranged at equal angles around the front edge of the weld (the sampling hole is 1.5 mm from the near wall and the port is chamfered by 0.3 mm to reduce the nozzle effect), and miniature thermocouples T1…T8 are arranged at eight positions upstream of the inlet of each branch stream for step tracking of residence time.

[0172] Pressure and temperature sampling period is 50ms, and clock is triggered by linear speed encoder, with synchronization alignment error ≤10ms;

[0173] After power-on, the pressure and temperature channels are zeroed for 60 seconds using the static zero pressure and constant temperature range.

[0174] The circumferential pressure difference is defined as the range of circumferential pressure at the same moment:

[0175] ΔPθ(t) = max(Pi(t)) − min(Pi(t)), and the engineering judgment value is taken as the 95th percentile within a 1s sliding window.

[0176] The residence time is determined using the small step to derivative peak method:

[0177] Apply a +2% 3s step to the total heating power of the shunt section (temperature zone maintained, linear velocity constant), record the response from T1 to T8, calculate the temperature derivative using the central difference of 100–200ms, take the arrival time ti corresponding to the derivative peaks of the 8 channels respectively, calculate the mean μt and standard deviation σt, and report the residence time standard deviation σt / μt×100%.

[0178] The shear rate is approximated using a slit:

[0179] The equivalent cross-sectional dimensions of the i-th strand are taken from the nominal values ​​(bi, hi) on the mold drawing. The volume distribution αi (the proportion of the i-th strand to the total flow rate) is given by the "inlet angle-ratio" calibration function. Then the approximate shear rate is... ,by As an indicator of shear rate range.

[0180] The calibration process was carried out after v≈12.0m / min and the material temperature stabilized.

[0181] Keeping other conditions constant, each of the eight entrance angles was scanned by a small amplitude of ±1.0° (0.1° step) around its nominal angle, and the sensitivity of volume distribution to angle was measured. The measured range is 0.6% / °–0.9% / °;

[0182] The fitting yields a linear approximation αi(δθi) = αi0 + kiδθi( By maintaining proportional normalization, the response trends of "ΔPθ, σt / μt, and shear rate range" with (δθ1…δθ8) were recorded.

[0183] Online execution employs a two-stage adjustment law: Stage A is coarse adjustment, where the smallest 95th percentile of ΔPθ is selected from three preset entry angle combinations as the initial stage;

[0184] Phase B fine-tuning involves calculating the current 8-point pressure deviation every 200ms. Update the entrance angle δθinew=clip(δθiold–g·ei,–0.3°,+0.3°) according to the proportional law, where g is 0.05% / 100Pa;

[0185] After each update, observe for ≥10 seconds and recalculate the 95th percentile of ΔPθ and the two consistency indices until the following criteria are met simultaneously: ① ΔPθ ≤ 1000 Pa; ② σt / μt ≤ 8%; ③ Shear rate range ≤ 10%.

[0186] To avoid oscillations caused by stepping, a protection logic is set: if a divergence occurs after three consecutive iterations where "ΔPθ decreases but σt / μt or shear rate range increases," g is automatically reduced by 50%; if the 95th percentile of ΔPθ repeatedly crosses the window (>1000Pa) ≥2 times within 30 seconds, all δθi are rolled back to the previous set of angles that satisfy the window and the observation time is extended to 30 seconds. After adjustment, δθi is locked, and continuous production begins.

[0187] Every 500m of production, a microstep is triggered to the derivative peak to verify the standard deviation of the residence time.

[0188] To demonstrate the contribution of this operating condition constraint to downstream quality and stability, three sets of references were set: E (nominal angle, no proportioning or fine-tuning), F (only differential pressure meets the standard, ignoring retention and shear consistency), and H (overcorrection, g is magnified by one time and no 10s hold is set).

[0189] The scheme in this embodiment is denoted as G (differential pressure meets the standard and both consistency requirements are met simultaneously).

[0190] Four groups continuously produced ≥300m under the same materials and line speed. The results are as follows:

[0191] Table #3 shows the process and quality data for achieving differential pressure, consistency, and three reference schemes.

[0192]

[0193] Data shows that at the same linear velocity (12.0 m / min), only meeting the pressure difference standard can reduce ΔPθ to within the window. However, if the consistency of retention and shear is not considered, the variance of circumferential corrugation and wall thickness is still higher than the case where both consistency requirements are met simultaneously.

[0194] While over-correction can achieve similar ΔPθ and consistency metrics as in this embodiment, it will result in a larger total step size and higher convergence time and process variability.

[0195] like Figure 1-4 As shown, the following sampling and control rules are executed during S1 and S2:

[0196] Temperature and pressure data at no less than 6 locations are collected synchronously in the circumferential direction of the welding cavity, with a sampling period of no more than 50ms. The timestamp and linear velocity encoding are synchronized, and the alignment error is no more than 10ms.

[0197] The rate of change of temperature over time was calculated using the central difference within a time window of 100ms to 200ms, and its peak value was defined as the maximum derivative within a 1s moving window.

[0198] The circumferential pressure difference is defined as the difference between the maximum and minimum values ​​of the circumferential pressure samples taken at the same time.

[0199] Each control cycle updates the phase change material cavity power fine-tuning and conformal flow channel power fine-tuning according to the feedforward plus integral control strategy. The control cycle is no more than 200ms, and the single update amplitude is no more than 10% of the rated power.

[0200] Within two consecutive control cycles, the two thresholds specified by S2 must be met simultaneously: the peak value of the rate of change of temperature over time ≤ 1℃ / s and the circumferential pressure difference of the welding cavity ≤ 1000Pa.

[0201] In this embodiment, the object of the extrusion is the seamless aluminum sheath forming of a 35kV power distribution cable; the target outer diameter is 30mm and the nominal wall thickness is 2.5mm; the aluminum billet is grade 1050; and the extrusion equipment is a 2000t horizontal split welding production line.

[0202] The baseline linear velocity V0 was obtained by averaging the results after 5 minutes of stable operation under normal absolute temperature control and normal shaping without enabling advanced control, resulting in V0 = 12.0 m / min.

[0203] In this embodiment, the linear velocity throughout the entire process is 12.0 m / min (≥0.9·V0).

[0204] Eight temperature points and eight pressure points are arranged at equal angles around the circumference of the welding area. The distance from the sensor to the near wall is 1.5 mm. The sampling period is 50 ms. All channels are triggered by the interruption of the linear speed encoder, and the hardware timestamp alignment error is ≤10 ms.

[0205] Before going live, a 60-second static zero-point calibration and channel delay calibration were performed (square wave pulse injection, relative delay measured by cross-correlation method and phase compensation performed) to ensure cross-channel synchronization. The calculable definitions of temperature derivative and circumferential pressure difference are as follows: For each temperature channel Ti(t), the derivative is calculated using central difference, with a time window of 100–200 ms.

[0206] ;

[0207] Within a 1-second moving window, the maximum absolute value of the derivative taken over all circumferential points is taken as the peak rate of temperature change over time. .

[0208] The circumferential pressure difference is defined as the range at the same moment. .

[0209] Based on operating conditions, the operational target is: and .

[0210] The actuator is a ring-shaped induction heating power. Phase change material cavity power Heat exchange with conformal flow channel An update is performed every 200ms (control cycle 200ms), and the change to either execution end in a single update does not exceed 10% of the rated value of that end. To avoid the two objectives hindering each other, a normalization error is introduced, and updates are performed in the direction of the "most pressing objective."

[0211] ;

[0212] ;

[0213] ;

[0214] The update pattern employs feedforward and integration, combined with single-step quantization and anti-saturation protection:

[0215] ;

[0216] in , , .

[0217] This example uses the following parameters: , , , ; , (Unit is "rated share / cycle").

[0218] To prevent integral saturation, if If the single-step limit is hit, the integral component of that cycle is frozen;

[0219] Numerical example (achieved within two cycles): Initial °C / s, Pa, then

[0220] Immediately after each update, assess whether the current period's objectives have been met compared to the previous period.

[0221] If the conditions are met for two consecutive control cycles °C / s and Pa, denoted as achieved.

[0222] If any cycle fails to meet the requirements, the update continues in the same direction until the desired result is achieved. If two consecutive cycles show a divergence between the temperature derivative and the pressure difference (one decreasing and the other increasing), the three actuators are temporarily slowed down. Reduce the step limit to 50% and lower the single-step limit to 7%, then restore after 3 cycles.

[0223] If sampling frames are lost or the time alignment error is greater than 10ms, pause the update and only maintain the output of the current execution end until synchronization is restored.

[0224] initial °C / s, Pa, then , .

[0225] by For example, the increment of the first control cycle (4.2% rated, below the 10% upper limit);

[0226] After execution °C / s, Pa.

[0227] The second cycle involves a 3-5% increase in the rated value in the same direction, reducing the indicator to [a lower level]. °C / s, Pa, achieved within two cycles.

[0228] To demonstrate the necessity of sampling period, time synchronization, control period, and single-step limiting for achieving the two periods, four typical controls were set up: A (sampling 100ms), B (sampling 50ms but channels are not synchronized, maximum alignment error ≈ 40ms), C (control period 500ms), and D (single-step allowance 20% of the rated value, easy to over-adjust).

[0229] In this embodiment, it is denoted as M (sampling 50ms, synchronization ≤10ms, control cycle 200ms, single step ≤10%).

[0230] Under the same linear speed and material conditions, continuous production of ≥300m yielded the following results:

[0231] Comparison of control strategies for achieving dual thresholds in two cycles (Table #4)

[0232]

[0233] The two-cycle agreement can only be achieved in Group M;

[0234] Group A has an overestimated derivative estimate and delayed response due to a sampling time of 100ms, so it needs ≥5 cycles;

[0235] Group B suffers from unstable directional updates due to phase errors introduced in derivative and pressure difference calculations caused by a 40ms synchronization drift.

[0236] Group C's control cycle is too long; although the magnitude of individual actions is compliant, the response is slow.

[0237] Although Group D can enter the window in 3 periods, it has the most oscillation events and obvious fluctuations in wall thickness variance and energy consumption due to frequent over-adjustment of 20% per step.

[0238] Group M achieved the smallest ripple amplitude (45μm) and the lowest wall thickness variance (95μm²) at the same linear velocity, and had no oscillation events within 300m;

[0239] A 99% pass rate and a minimum energy consumption of 21.2 kWh / 1000m demonstrate the comprehensive benefits of its short cycle, small steps, and strict synchronization.

[0240] like Figure 1-4 As shown, during the control processes of S2 and S5, the melting temperature range of the phase change material is set to cover ±5°C of the target welding temperature, and the latent heat per unit volume is 180kJ per liter to 350kJ per liter.

[0241] The effective thermal conductivity near the wall of the welding cavity is adjusted by heat exchange through conformal flow channels, so that the ratio of the effective thermal conductivity near the wall to the effective thermal conductivity near the wall when the conformal flow channels are not opened is 1 to 3.

[0242] The phase change material cavity power fine-tuning adopts a quantization stepping method, with a single update stepping amplitude of 1% to 10% of the rated power and an update interval of no less than 2 sampling cycles;

[0243] When the linear velocity remains at no less than 90% of the baseline operating condition, the above interval and step rules continue to be executed;

[0244] In this embodiment, the implementation object and production line conditions are the same as in the previous embodiment, both using seamless aluminum sheathing of 35kV power distribution cable, with a target outer diameter of 30mm and a nominal wall thickness of 2.5mm;

[0245] The aluminum billet is grade 1050; the extrusion equipment is a 2000t horizontal split-flow and welded production line.

[0246] The baseline linear velocity V0 was averaged after 5 minutes of stable operation under conventional absolute temperature control and conventional shaping, with V0 = 12.0 m / min; in this embodiment, the operating linear velocity is constant at 12.0 m / min (≥0.9·V0).

[0247] To meet the limitations of the phase change window and near-wall thermal conductivity, a phase change material cavity (PCM module) and a conformal flow channel (adjustable flow rate wall-mounted heat exchange channel) are installed near the welding cavity, and the following calibration and control are adopted:

[0248] Based on a dual-threshold stabilization window, without changing the linear velocity, two embedded K-type thermocouples (0.5 mm and 2.5 mm from the wall) are placed near the wall of the welding section. The center of the target temperature range is measured using a 10-minute steady-state test. (The temperature point that minimizes the combined index of circumferential ripple amplitude and wall thickness variance; the minimum value is obtained on the temperature-quality index curve using the 3-point method). Based on this, the melting temperature range is selected. A combination of high-temperature phase change materials (industrial high-temperature phase change salts or metallic eutectics are acceptable, as long as they meet the latent heat and reliability requirements described later) with a temperature range of ±5℃ was used to confirm the latent heat per unit volume using differential scanning calorimetry (DSC). It is located in the range of 180-350 kJ / L.

[0249] This embodiment selects The PCM module has a capacity of approximately 240 kJ / L and a total effective volume of 1.2 L. The thermal contact surface covers the near-wall circumferential direction of the welding cavity by 120°.

[0250] Under the action of PCM / flow channel, the near-wall equivalent thermal conductivity varies with power and flow rate.

[0251] The effective thermal conductivity near the wall was estimated online using a heat flow meter and the two-point temperature gradient method. :

[0252] The surface heat flow was measured by an embedded heat flow meter 1.0 mm below the wall. (W / m2), using the temperature difference between two points and detection distance difference mm approximate normal gradient Based on this calculation:

[0253] ;

[0254] When the conformal flow channel heat exchange is not activated and the PCM is in solid-state standby mode For reference, during operation, the ratio is adjusted by regulating the flow rate in the flow channel and the power of the PCM. Maintain at 1–3. The target ratio for this embodiment is set at 2.0 ± 0.3;

[0255] The PCM module is equipped with a 2.0kW heating / 1.5kW active cooling capacity, and the conformal flow channel has a maximum heat transfer equivalent of 5kW. Both actuations adopt quantitative stepping.

[0256] The step size for each update is 1-10% of the corresponding rated capacity, and the update interval is not less than 2 sampling cycles (this line samples 50ms, so the update interval is ≥100ms, and the actual interval is 200ms, which is consistent with the control cycle).

[0257] To suppress overcorrection, if in any period or If the pressure is 900Pa, the upper limit of the step size for this cycle will automatically be tightened to 5% of the rated value.

[0258] by Threshold L, ΔP pcm ΔQflow The triadic mapping is used to give the target step;

[0259] When the required step exceeds the 1-10% limit of this clause, execution will be truncated in the same direction and deferred to the next cycle; if If the upper limit of 3.0 is reached but the dual threshold is still not met, the PCM step size will be increased first, and the flow channel heat exchange will not be increased, in order to avoid near-wall overcooling and embrittlement of the weld interface.

[0260] Four control strategies were set up under the same production line and material conditions: R (no PCM, no flow channel, absolute temperature control only), S (flow channel only, target) and S (flow channel only, target material only). (No PCM), T (PCM melt window is too narrow) C kJL), U (PCM melt window is too wide, C kU / L, low latent heat), and V (PCM) in this embodiment kJ / L, in conjunction with the flow channel 2.0).

[0261] All five groups were continuously produced for ≥300m at an online speed of 12.0m / min. The process and quality indicators were recorded using a unified method. The experimental results are as follows:

[0262] Comparison of phase change window and near-wall thermal conductivity processes and quality indicators (Table #5)

[0263]

[0264]

[0265] Two cycles were achieved only in Group M; Group A, due to a 100ms sampling period, resulted in an overestimated derivative and delayed response, requiring ≥5 cycles; Group B, due to a 40ms synchronization drift, introduced phase errors in the derivative and differential pressure calculations, causing unstable directional updates; Group C had an excessively long control cycle, and although the amplitude of individual actions was compliant, the response was slow; Group D, although it could enter the window with 3 cycles, experienced the most oscillation events and significant fluctuations in wall thickness variance and energy consumption due to frequent over-adjustments of 20% per step.

[0266] Group M achieved the minimum ripple amplitude (45μm) and the lowest wall thickness variance (95μm²) at the same linear speed, with no oscillation events within 300m; the first-pass yield was 99% and the lowest energy consumption was 21.2kWh / 1000m, thus demonstrating the advantages of this scheme in short cycle, small step, and strict synchronization.

[0267] like Figure 1-4 As shown, the circumferential ripple phase obtained by S3 drives the fine-tuning of the shaping roller speed of S4, which is performed according to the following anti-vibration decoupling rules:

[0268] The roller speed modulation adopts a single-frequency or dual-frequency method, and the modulation period is an integer multiple of the control period, with the multiple not less than 3;

[0269] Each control cycle only updates the roller speed modulation parameters once. The update adopts quantization stepping, and the single update amplitude is no more than 1% of the linear speed. The phase prediction error is limited to 10°.

[0270] The roller speed modulation and the temperature change rate closed loop are decoupled from each other. The modulation period is kept as an integer multiple of the control period and not less than 3 times. The modulation phase and the circumferential ripple phase are out of phase.

[0271] When signs of coupled oscillation appear, self-recovery is performed: if the circumferential ripple amplitude does not decrease within two consecutive modulation cycles and the peak value of the rate of change of temperature over time is close to or greater than 80% of the threshold, the modulation cycle is increased to a higher integer multiple and the modulation amplitude is reduced by 20% to 50% until the circumferential ripple amplitude decreases and recovers to the stable window.

[0272] The following rules are applied in the joint objective optimization of S6:

[0273] The joint objective is the weighted sum of the square of the eccentricity and the energy consumption per unit length, with the sum of the two weights being 1, and the initial values ​​all falling between 0.2 and 0.8.

[0274] The update cycle is no more than 1 second, and the weight change in each update is no more than 0.05.

[0275] The moving average of the last three update cycles is used as the judgment criterion: when the eccentricity increases but the energy consumption per unit length does not decrease, the weight corresponding to the eccentricity is increased and the weight corresponding to the energy consumption is decreased by the same amount; when the energy consumption per unit length increases but the eccentricity does not decrease, the weight corresponding to the energy consumption is increased and the weight corresponding to the eccentricity is decreased by the same amount; when both increase simultaneously, the step size is halved; when both decrease simultaneously, the weights remain unchanged.

[0276] When the eccentricity and the moving average of energy consumption per unit length both fall within their respective set thresholds during a continuous 60-second run, the weight update is stopped; if either indicator exceeds the set threshold and remains so for 10 seconds, the weight update is restarted.

[0277] Online micro-leakage detection and corrective action are implemented between S3 and S5, specifically including:

[0278] A differential suction and labeling gas concentration comparison method is adopted. Trace amount of labeling gas is introduced into the core of the sheath. The concentration ratio of the peripheral background and near-wall suction is calculated within a 1-second window. The timestamp and linear velocity encoding are synchronized, with an alignment error of no more than 10ms. If the concentration ratio exceeds the threshold, it is judged as a leak.

[0279] Leakage location is given by linear velocity and time for axial coordinates and by rotary encoder pulse count for circumferential coordinates. The location resolution is not less than 5 mm and the minimum detectable leakage rate reaches 10 to the power of -9 Pa·m³ / s.

[0280] When a leakage event occurs, within an axial window length of no more than 100 mm in the vicinity of the leakage coordinate, local reverse phase fine adjustment is performed on the segmented shaping of S4, the roller speed modulation amplitude does not exceed 1% of the linear speed, and the duration of a single local correction does not exceed 15 s.

[0281] When a leakage event is triggered, the peak limit of the temperature change rate of S2 over time is temporarily tightened, with the tightening range being 10% to 30% of the current setting. After the tightening ends, the setting is restored to the previous setting in equal steps.

[0282] The release condition is that the concentration ratio is updated twice consecutively to be below 80% of the threshold, or if the concentration ratio is not reduced after local correction for 10 seconds, the axial window will be enlarged to twice the original value and an alarm will be recorded, while the linear velocity will be kept at no less than 90% of the baseline operating condition.

[0283] This embodiment was carried out on a 2000t horizontal shunt-welding aluminum extrusion line, with a target outer diameter of 30mm, a nominal wall thickness of 2.5mm, and aluminum material of grade 1050.

[0284] The baseline linear velocity V0 was obtained by running stably for 5 minutes without enabling advanced control through conventional temperature control and conventional shaping to achieve 12.0 m / min; the linear velocity was maintained at no less than 0.9·V0 throughout the process, and 12.0 m / min was used in this embodiment.

[0285] Eight temperature and eight pressure sensors are arranged circumferentially in the welding area, with a sampling period of 50ms. The clock alignment error with the rotary encoder is no more than 10ms, and the control period is 200ms.

[0286] At 150mm after the forming exit, a linear array camera at 4kHz and a 4096ppr encoder are used to synchronously acquire the circumferential signal. The signal is reconstructed at 2048 equal angles per revolution and filtered by a Hanning window bandpass filter to obtain the fundamental frequency complex coefficient C1. The phase φ = arg(C1) (degrees) is used. The reference phase is the predicted value of the previous control cycle. The phase offset Δφ that is folded back to (−180°, 180°) is calculated, and the absolute value |φ| is used for control mapping. The phase prediction adopts the linear extrapolation of the most recent three cycles, and the prediction error is limited to 10°.

[0287] The rate of temperature change over time was calculated using the central difference within a 100–200 ms window, and the maximum absolute value of the derivative of each circumferential point within a 1 s moving window was defined as the peak rate of change.

[0288] The range of circumferential pressure at the same moment is defined as the circumferential pressure difference. The dual thresholds are a peak change rate not exceeding 1℃ / s and a circumferential pressure difference not exceeding 1000Pa.

[0289] Downstream shaping uses three-section compliant rollers. The roller speed fine-tuning signal is superimposed on the linear speed in a way that is out of phase with the current circumferential ripple. The amplitude of a single section does not exceed 1% of the linear speed. The modulation period is 3 or 4 times the control period, and the modulation parameters are updated only once in each control period.

[0290] To avoid subharmonic coupling with the temperature-to-pressure closed loop, the modulation period is fixed to an integer multiple of the control period and not less than 3 times.

[0291] If the circumferential ripple amplitude does not decrease within two consecutive modulation cycles and the peak temperature change rate exceeds 80% of the current threshold, the modulation cycle will be automatically increased to a higher integer multiple (3→4 or 4→6), and the amplitude will be reduced by 20% to 50% until the ripple amplitude decreases and enters a stable window, after which it will be restored to the original integer multiple and amplitude.

[0292] The upstream thermal management actuator includes a phase change material cavity and a conformal flow channel heat exchanger. The power step of both is given by the mapping between |φ| and linear velocity. The single step is 5% to 50% of their respective rated capacity, and the update cycle is consistent with the control cycle.

[0293] When the absolute value of the phase offset increases, the target rate of change tightens monotonically, with the two execution ends increasing synchronously; when the offset decreases, all three values ​​loosen in the same direction, and the single loosening amplitude does not exceed the previous tightening amplitude. The linear velocity remains at no less than 90% of the baseline operating condition during the execution of shaping modulation and thermal control mapping.

[0294] During the climbing phase, a joint objective is introduced: J = w1·(eccentricity)² + w2·energy consumption per unit length E, where w1 + w2 = 1, with initial values ​​of 0.5 / 0.5 and boundary values ​​of 0.2 to 0.8. The update cycle is 1 second, and each weight change is no greater than 0.05.

[0295] The criterion is the moving average of the last three updates:

[0296] If the eccentricity increases but the energy consumption does not decrease, then increase w1 and decrease w2 by the same amount; if the energy consumption increases but the eccentricity does not decrease, then increase w2 and decrease w1 by the same amount; if both increase simultaneously, the step size is halved; if both decrease simultaneously, the weights remain unchanged.

[0297] The weights are frozen after both indicators simultaneously reach the preset thresholds (eccentricity not higher than 0.80% and energy consumption per unit length not higher than 21.5 kWh / 1000m) for 60 consecutive seconds; the update is restarted when either indicator exceeds the threshold for 10 seconds.

[0298] The above weights only affect the target selection of power allocation and shaping parameters, and do not change the hard constraints of dual thresholds and linear velocity;

[0299] Online micro-leakage detection employs a differential suction and labeled gas concentration ratio method. 50 ppm helium is continuously introduced into the sheath core using a mass flow valve. Two micro-suction channels, one at 0.5 L / min and one near the wall, are connected to the same gas analyzer (T90 not exceeding 300 ms). The concentration ratio R(t) is calculated using a 1-second window: R(t) = Cnearwall / (Cbg+). Take 10 -6 PPM zeroing is prevented, and the synchronization and alignment error between the timestamp and the linear velocity encoding is no greater than 10ms.

[0300] The threshold is set to the steady-state background mean plus three standard deviations, corresponding to a value of 1.30; when R exceeds the threshold, it is determined to be a leak.

[0301] Axial coordinates are expressed as x = v·(tt) The calculations, using encoder pulse counts converted to angles, achieve a positioning resolution of at least 5mm and a minimum detectable leakage rate of 10. -9 Pa-m3 / s (calibrate with a standard leak hole and record the calibration curve before opening the line).

[0302] When a leakage event occurs, within a range of no more than 100 mm in the axial window length of the leakage coordinate neighborhood, local phase reversal fine adjustment is performed on the segmented shaping, the roller speed modulation amplitude does not exceed 1% of the linear speed, and the duration of a single local correction does not exceed 15 s; at the same time, the temperature change rate threshold target is tightened by 10%~30% for a short time, and after the end, it is restored to the setting before tightening in equal steps.

[0303] The release condition is that the concentration ratio is updated twice consecutively below 80% of the threshold, or if the concentration ratio is not reduced after local correction for 10 seconds, the axial window is enlarged to twice the original value and an alarm is recorded; the overall linear velocity is kept at no less than 90% of the baseline T condition.

[0304] To ensure feasibility, the calculation and update rules for the above quantities are executed within the same clock frame: phase, temperature derivative, and circumferential pressure difference are calculated on a 50ms sampling period; thermal management and shaping parameters are updated on a 200ms control period and only once per cycle; the vibration damping modulation period is fixed as an integer multiple of the control period, the joint target weight is updated on a 1s period, and the leakage concentration ratio is determined on a 1s window.

[0305] When a timeout or frame loss occurs, the current update is frozen and the execution output is maintained until the clock recovers. If the phase prediction error exceeds 10° or the circumferential pressure difference exceeds 1000Pa for 1 second, the protection mode is entered for a short period of time: the modulation amplitude is reduced by 30%, and the thermal control step limit is temporarily tightened to the rated 5% until the dual thresholds are met again.

[0306] Based on the measurement point layout, time synchronization accuracy, calculation caliber, modulation and update parameters, and triggering and deactivation conditions disclosed in this section, those skilled in the art can directly reproduce the operation process of anti-vibration decoupling, joint target optimization, and online micro-leakage linkage on similar production lines. Without reducing the linear speed, they can achieve synchronous improvement in circumferential ripple amplitude, wall thickness variance, eccentricity, and energy consumption per unit length. At the same time, they can realize online detection and local correction of leaks, thereby ensuring that the solution can be repeatedly implemented.

[0307] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0308] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A forming process for a cable, an aluminum extrusion device, and a seamless aluminum sheath, characterized in that, Includes the following steps: S1, in the welding cavity with an equal pressure ring and logarithmic spiral rectifier groove, the aluminum flow from the diversion hole is rectified and welding is completed; S2, a conformal flow channel and a phase change material cavity are set near the wall of the welding cavity, and multiple temperature and circumferential pressure data of the welding area are collected. Through the coordinated control of heating and heat exchange, the peak value of the temperature change rate of the welding area with time is not higher than 1℃ per second, and the circumferential pressure difference of the welding cavity is not higher than 1000Pa. S3, online acquisition of the phase and fundamental frequency of the formed circumferential ripple, and synchronization with the linear velocity; S4, based on the phase, perform reverse phase fine adjustment on the downstream segmented compliant shaping so that the roller speed modulation amplitude does not exceed 1% of the linear speed and the phase prediction error is not higher than 10°. S5, establish a real-time mapping between the phase and the temperature change rate threshold of step 2, and trigger power fine-tuning of the phase change material cavity and conformal flow channel accordingly, so that ripple suppression and welding stability are satisfied at the same time, and the linear velocity is not lower than 90% of the baseline condition during the execution of S4 and S5; S6 uses the weighted sum of the square of the eccentricity and the energy consumption per unit length as the auxiliary target for the climbing stage, and updates the weights online according to preset rules so that the eccentricity and the energy consumption per unit length decrease simultaneously to within the set threshold.

2. The forming process of the cable, aluminum extrusion equipment, and seamless aluminum sheath according to claim 1, characterized in that, Real-time mapping in S5 satisfies the following constraints: The real-time mapping is a monotonic relationship, which is achieved by piecewise linear interpolation or spline interpolation. The independent variables are the circumferential ripple phase obtained by S3 and the synchronous linear velocity. The output includes the following three adjustment items: the upper limit of the peak value of the rate of change of temperature over time, the power fine-tuning of the phase change material cavity, and the power fine-tuning of the conformal flow channel. As the phase offset of the circumferential ripple increases, the upper limit of the peak value of the rate of change of temperature with time tightens according to a monotonically decreasing relationship, and the adjustment amount of the phase change material cavity power fine-tuning and the adjustment amount of the conformal flow channel power fine-tuning decrease synchronously. When the shift of the circumferential ripple phase decreases, the upper limit of the peak value of the rate of change of temperature with time is relaxed in a monotonically increasing relationship. The adjustment amount of the phase change material cavity power fine-tuning and the adjustment amount of the conformal flow channel power fine-tuning are increased synchronously, and the relaxation amount each time does not exceed the corresponding tightening amount. Each time the mapping is updated, the adjustment amount of the upper limit of the peak value of the rate of change of temperature over time is 5% to 50% of the previous setting; the adjustment amount of the phase change material cavity power fine-tuning is 5% to 50% of their respective previous settings, and is consistent with the adjustment direction of the upper limit of the peak value of the rate of change of temperature over time. The adjustment amount of the conformal flow channel power fine-tuning is 5% to 50% of the previous setting value, and is consistent with the adjustment direction of the upper limit of the peak value of the temperature change rate over time. The real-time mapping converges within two consecutive updates, and the update period is consistent with the control period.

3. The forming process of the cable, aluminum extrusion equipment, and seamless aluminum sheath according to claim 1, characterized in that, During S1 and S2, the maximum difference in the circumferential pressure distribution of the welding cavity within the axial target section is controlled to be ≤1000Pa; at the same time, the volume distribution of each diverter and the inlet angle are matched according to the preset ratio, so that the standard deviation of the residence time before welding is ≤8%, and the range of the shear rate before welding is ≤10%.

4. The forming process of the cable, aluminum extrusion equipment, and seamless aluminum sheath according to claim 1, characterized in that, The following sampling and control rules are executed during S1 and S2: Temperature and pressure data at no less than 6 locations are collected synchronously in the circumferential direction of the welding cavity, with a sampling period of no more than 50ms. The timestamp and linear velocity encoding are synchronized, and the alignment error is no more than 10ms. The rate of change of temperature over time was calculated using the central difference within a time window of 100ms to 200ms, and its peak value was defined as the maximum derivative within a 1s moving window. The circumferential pressure difference is defined as the difference between the maximum and minimum values ​​of the circumferential pressure samples taken at the same time. Each control cycle updates the phase change material cavity power fine-tuning and conformal flow channel power fine-tuning according to the feedforward plus integral control strategy. The control cycle is no more than 200ms, and the single update amplitude is no more than 10% of the rated power. Within two consecutive control cycles, the two thresholds specified by S2 must be met simultaneously: the peak value of the rate of change of temperature over time ≤ 1℃ / s and the circumferential pressure difference of the welding cavity ≤ 1000Pa.

5. The forming process of the cable, aluminum extrusion equipment, and seamless aluminum sheath according to claim 1, characterized in that, During the control process of S2 and S5, the melting temperature range of the phase change material is set to cover ±5°C of the target welding temperature, and the latent heat per unit volume is 180kJ per liter to 350kJ per liter. The effective thermal conductivity near the wall of the welding cavity is adjusted by heat exchange through conformal flow channels, so that the ratio of the effective thermal conductivity near the wall to the effective thermal conductivity near the wall when the conformal flow channels are not opened is 1 to 3. The phase change material cavity power fine-tuning adopts a quantization stepping method, with a single update stepping amplitude of 1% to 10% of the rated power and an update interval of no less than 2 sampling cycles; When the linear velocity is maintained at no less than 90% of the baseline operating condition, the above interval and step rules continue to be executed.

6. The cable, aluminum extrusion equipment, and seamless aluminum sheath forming process according to claim 1, characterized in that, The circumferential ripple phase obtained from S3 drives the fine-tuning of the shaping roller speed in S4, which is performed according to the following anti-vibration decoupling rules: The roller speed modulation adopts a single-frequency or dual-frequency method, and the modulation period is an integer multiple of the control period, with the multiple not less than 3; Each control cycle only updates the roller speed modulation parameters once. The update adopts quantization stepping, and the single update amplitude is no more than 1% of the linear speed. The phase prediction error is limited to 10°. The roller speed modulation and the temperature change rate closed loop are decoupled from each other. The modulation period is kept as an integer multiple of the control period and not less than 3 times. The modulation phase and the circumferential ripple phase are out of phase. When signs of coupled oscillation appear, self-recovery is performed: if the circumferential ripple amplitude does not decrease within two consecutive modulation cycles and the peak value of the rate of change of temperature over time is close to or greater than 80% of the threshold, the modulation cycle is increased to a higher integer multiple and the modulation amplitude is reduced by 20% to 50% until the circumferential ripple amplitude decreases and recovers to the stable window.

7. The forming process of the cable, aluminum extrusion equipment, and seamless aluminum sheath according to claim 1, characterized in that, The following rules are applied in the joint objective optimization of S6: The joint objective is the weighted sum of the square of the eccentricity and the energy consumption per unit length, with the sum of the two weights being 1, and the initial values ​​all falling between 0.2 and 0.

8. The update cycle is no more than 1 second, and the weight change in each update is no more than 0.

05. The moving average of the last three update cycles is used as the judgment criterion: when the eccentricity increases but the energy consumption per unit length does not decrease, the weight corresponding to the eccentricity is increased and the weight corresponding to the energy consumption is decreased by the same amount; when the energy consumption per unit length increases but the eccentricity does not decrease, the weight corresponding to the energy consumption is increased and the weight corresponding to the eccentricity is decreased by the same amount; when both increase simultaneously, the step size is halved; when both decrease simultaneously, the weights remain unchanged. When the eccentricity and the moving average of energy consumption per unit length both fall within their respective set thresholds during a continuous 60-second run, the weight update is stopped; if either indicator exceeds the set threshold and remains so for 10 seconds, the weight update is restarted.

8. The forming process of the cable, aluminum extrusion equipment, and seamless aluminum sheath according to claim 5, characterized in that, Online micro-leakage detection and corrective action are implemented between S3 and S5, specifically including: A differential suction and labeling gas concentration comparison method is adopted. Trace amount of labeling gas is introduced into the core of the sheath. The concentration ratio of the peripheral background and near-wall suction is calculated within a 1-second window. The timestamp and linear velocity encoding are synchronized, with an alignment error of no more than 10ms. If the concentration ratio exceeds the threshold, it is judged as a leak. Leakage location is given by linear velocity and time for axial coordinates and by rotary encoder pulse count for circumferential coordinates. The location resolution is not less than 5 mm and the minimum detectable leakage rate reaches 10 to the power of -9 Pa·m³ / s. When a leakage event occurs, within an axial window length of no more than 100 mm in the vicinity of the leakage coordinate, local reverse phase fine adjustment is performed on the segmented shaping of S4, the roller speed modulation amplitude does not exceed 1% of the linear speed, and the duration of a single local correction does not exceed 15 s. When a leakage event is triggered, the peak limit of the temperature change rate of S2 over time is temporarily tightened, with the tightening range being 10% to 30% of the current setting. After the tightening ends, the setting is restored to the previous setting in equal steps. The release condition is that the concentration ratio is updated twice consecutively to below 80% of the threshold, or the concentration ratio is not reduced after local correction for 10 seconds. In this case, the axial window is enlarged to twice the original value and an alarm is recorded. The linear velocity is kept at no less than 90% of the baseline condition.

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