Secondary cable terminal head welding tongs and welding control method

Abstract

The present application relates to the technical field of power connection, in particular to a secondary cable terminal head welding clamp and a welding control method thereof, the clamp head of the welding clamp is provided with a heating and pressing part, a welding point temperature measuring unit and a wire core side temperature measuring unit, the handle is provided with a temperature control evaluation unit and a force sensing unit; the method collects the welding point temperature, the wire core side temperature and the pressing force, adjusts the heating power according to the welding point temperature to track the target temperature, evaluates the welding qualification degree according to the welding point temperature, the pressing force and the solder phase change characteristics and outputs the qualified or re-welding prompt, cuts off the heating power when the wire core side temperature reaches the wire core insulation temperature threshold or the temperature rising rate exceeds the threshold; the present application makes the terminal welding temperature controllable, the wire core is not scalded, the welding quality can be judged on the operation site, and solves the problems that the existing process is heated by experience, the wire core is easily scalded, the welding is easily virtual, and the quality cannot be judged.

Description

Technical Field

[0001] This invention relates to the field of power connection technology, specifically to a welding clamp for secondary cable terminations and a welding control method. Background Technology

[0002] Secondary cables are commonly used in the control circuits and control power supply circuits of substations, power distribution rooms, and various control panels. The quality of the grounding wires at the terminals directly affects the signal integrity and control reliability of the secondary circuits. There are two common methods for connecting the grounding wires to the cable armor on site: one is direct wrapping and binding, and the other is spot welding the grounding wire to the armor with a soldering iron, followed by restoring the external insulation with insulating tape, wrapping tape, or heat shrink sleeve.

[0003] The problems with these two methods lie in the uncontrollable temperature and unpredictable quality during the welding process. The wrapped and bound connections are unstable and prone to loosening due to equipment vibration and temperature cycling during operation, leading to increased contact resistance. When using general-purpose tools like soldering irons for spot welding, the heating temperature and time rely entirely on the operator's experience: if the temperature is too low or the heating time is insufficient, the solder cannot fully wet the welding surface, resulting in a weak weld and high contact resistance; if the temperature is too high or the heating time is too long, heat is conducted inward through the armor and wire core, burning the wire core insulation and creating a potential for insulation breakdown.

[0004] Furthermore, the quality of the welding cannot be determined on-site. If the cable is not securely fixed, it may shift or loosen under operating conditions such as vibration of power equipment or changes in ambient temperature, leading to problems such as poor contact and signal loss. In severe cases, it may cause the protection device to fail to operate or to malfunction, thereby expanding the scope of the fault. If the terminal manufacturing process is substandard, the conductor's current carrying capacity will be reduced after the core is burned, and it may even cause the insulation layer to age and break, inducing a short circuit fault. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a welding clamp for secondary cable terminations and a welding control method, which achieves controllable welding temperature, prevents the wire core from being burned, and enables on-site judgment of welding quality without increasing the complexity of the operation.

[0006] This invention is achieved through the following technical solution:

[0007] A secondary cable termination welding pliers, comprising: a pliers head and a handle;

[0008] The clamping head is equipped with a heating and clamping part, a solder joint temperature measuring unit and a wire core side temperature measuring unit. The heating and clamping part is used to heat and clamp the soldering terminals. The solder joint temperature measuring unit is located on the side of the clamping head near the solder joint, and the wire core side temperature measuring unit is located on the side of the clamping head near the wire core.

[0009] The grip is equipped with a temperature control evaluation unit and a force sensing unit, and the force sensing unit is located on the pressure transmission path of the heating and pressing part;

[0010] The temperature control evaluation unit is electrically connected to the heating and pressing part, the solder joint temperature measuring unit, the wire core side temperature measuring unit, and the force sensing unit, respectively.

[0011] Optionally, the clamp head is divided into an upper part and a lower part. The heating and clamping part is located in the upper part of the clamp head, and the lower part of the clamp head is provided with a heat-insulating temperature measuring part. The heat-insulating temperature measuring part is provided with a heat-insulating insert for inserting into the inner side of the cable armor. The core-side temperature measuring unit is located on the side of the heat-insulating temperature measuring part near the core, and the core-side temperature measuring unit is embedded in the side of the heat-insulating insert near the core.

[0012] Optionally, the handle is divided into a lower part and an upper part. The lower part of the handle is an operating handle for controlling the opening and closing and clamping of the pliers head. The upper part of the handle is provided with a temperature display unit, a temperature control evaluation unit, and a temperature control start / stop switch. The power supply for the welding pliers is introduced from the tail end of the handle.

[0013] A welding control method for secondary cable terminations includes the following steps:

[0014] The temperature of the solder joint, the temperature of the wire core side, and the clamping force are collected. The temperature of the solder joint is the temperature at the point where the welding terminal is welded to the cable armor. The temperature of the wire core side is the temperature on one side of the cable core. The clamping force is the clamping force applied to the welding terminal.

[0015] Adjust the heating power according to the solder joint temperature to make the solder joint temperature track the target temperature;

[0016] The welding qualification is evaluated based on the solder joint temperature, the clamping force, and the solder phase transformation characteristics, and a qualification prompt or resoldering prompt is output.

[0017] The heating power is cut off when the temperature on the core side reaches the core insulation temperature resistance threshold or when the temperature rise rate on the core side exceeds the rate threshold.

[0018] Optionally, the step of adjusting the heating power includes:

[0019] Identify the thermal process parameters of the weld joint online;

[0020] The temperature control parameters for tracking the target temperature are adjusted based on the thermal process parameters.

[0021] Optionally, the online identification specifically includes:

[0022] The thermal time constant of the solder joint thermal process is identified using recursive least squares method with forgetting factor;

[0023] The gain of proportional-integral-derivative control is tuned according to the thermal time constant;

[0024] The online identification is updated during the preheating phase and frozen during the welding phase.

[0025] The Smith predictor is used to compensate for the conduction hysteresis between heating and temperature measurement.

[0026] Optionally, the step of evaluating the weld qualification includes:

[0027] The welding qualification is calculated by multimodal fusion based on the solder joint temperature, the clamping force, the effective heat input during the welding stage, and the solder phase transformation characteristics.

[0028] The qualified prompt is output when the welding qualification reaches the qualified threshold; otherwise, the re-welding prompt is output.

[0029] Optionally, the multimodal fusion method includes:

[0030] The degree of wetting completion is determined by the stagnation of temperature rise caused by the latent heat of the solder molten phase transition.

[0031] Determine the heat input compliance, clamping force stability, and temperature plateau duration scaling;

[0032] The welding qualification is synthesized by adaptively weighting the heat input compliance, the clamping force stability, the temperature plateau duration scaling, and the wetting completion according to their respective confidence levels.

[0033] Optionally, the welding control method includes a preheating stage, a fusion stage, and a termination stage;

[0034] After the preheating stage is completed and the temperature is raised to the preheating temperature at full power, the welding stage begins.

[0035] During the welding phase, the weld joint temperature is maintained to track the target temperature and effective heat input is accumulated.

[0036] When the effective heat input reaches the target heat input, and the rate of change of the solder joint temperature is lower than the platform stability threshold, and this continues for a set duration, the process transitions to the termination phase.

[0037] Optionally, the core insulation temperature resistance threshold is no higher than 105°C when the cable sheath is made of polyvinyl chloride and no higher than 130°C when the cable sheath is made of cross-linked polyethylene.

[0038] This invention achieves closed-loop heating at the target temperature and on-site quality assessment based on indicators by simultaneously arranging solder joint temperature measurement and wire core temperature measurement in the clamping head, and incorporating a force sensing unit and a temperature control evaluation unit within the handle. Compared with existing technologies, this invention has the following advantages:

[0039] The solder joint temperature tracking system ensures that solder joints of different wire diameters and armor materials can be heated to the temperature required for full solder wetting, suppressing incomplete soldering and high contact resistance caused by insufficient temperature. Simultaneously, the temperature of the wire core is directly collected, and the heating power is cut off once the temperature reaches the wire core insulation temperature resistance threshold or its heating rate exceeds the set upper limit to avoid the risk of scalding the wire core. Finally, the soldering qualification is obtained by weighted multi-modal fusion of solder joint temperature, clamping force, effective heat input, and solder phase change characteristics, avoiding the reliance on human experience to determine whether it is qualified. Attached Figure Description

[0040] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, but do not constitute a limitation on the embodiments of the present invention.

[0041] Figure 1 This is a schematic diagram of the overall structure of the secondary cable termination welding clamp provided in an embodiment of the present invention;

[0042] Figure 2 This is a flowchart illustrating the secondary cable termination welding control method provided in an embodiment of the present invention.

[0043] Figure label:

[0044] 1-Clamping head; 11-Heating and clamping part; 111-Heating core; 12-Insulation and temperature measuring part; 13-Solder joint temperature measuring unit; 14-Wire core side temperature measuring unit; 2-Handle; 21-Temperature display unit; 22-Temperature control start / stop switch; 23-Operating handle; 24-Temperature control evaluation unit. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0046] It should also be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0047] Where there is no conflict, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] Example 1

[0049] This embodiment illustrates the structure of the secondary cable termination welding clamp.

[0050] like Figure 1 As shown, the welding clamp includes a clamp head 1 and a handle 2. The clamp head 1 is used to heat and clamp the welding terminals at the welding position, and the handle 2 is for one-handed operation by the operator and integrates control and display components.

[0051] The pliers head is divided into an upper part and a lower part.

[0052] The upper part of the clamp head 1 is a heating and clamping part 11. The heating and clamping part 11 has a built-in heating core 111. When the heating core 111 is energized, it forms a heating zone, which applies clamping force and heats the welding terminal placed on the cable armor, so that the welding terminal is fused with the armor.

[0053] The lower part of the clamp head 1 is provided with a heat-insulating temperature measuring part 12, which is equipped with a heat-insulating insert. The heat-insulating insert is inserted into the inside of the cable armor, which on the one hand positions the clamp head 1 on the armor, and on the other hand prevents the welding heat from being conducted to the wire core.

[0054] The solder joint temperature measuring unit 13 is located on the side of the clamp head 1 near the solder joint and is used to collect the solder joint temperature, which is the temperature of the welding terminal and the armor welding joint.

[0055] The core-side temperature measuring unit 14 is located on the side of the heat insulation temperature measuring part 12 near the core and is embedded in the side of the heat insulation insert near the core. It is used to collect the core-side temperature, which reflects the heating condition of the core side.

[0056] The heat insulation insert provides an installation position for the core-side temperature measurement unit 14 and places the temperature measurement point on the isolated low-temperature side, thereby enabling the core-side temperature to be collected independently of the solder joint temperature.

[0057] The grip is divided into a lower part and an upper part.

[0058] The lower part of the handle 2 is the operating handle 23, which controls the opening, closing and clamping of the jaws 1. The operator can control the opening and closing of the jaws and the application of clamping force with one hand.

[0059] The force sensing unit is set on the clamping force transmission path of the heating and clamping part 11 to collect the clamping force, that is, the clamping force applied to the welding terminal.

[0060] The upper part of the grip 2 is equipped with a temperature display unit 21, a temperature control evaluation unit and a temperature control start / stop switch 22, and the power supply for the welding clamp is introduced from the tail end of the grip 2.

[0061] The temperature control evaluation unit is electrically connected to the heating and pressing part 11, the solder joint temperature measuring unit 13, the wire core side temperature measuring unit 14 and the force sensing unit, respectively. It receives the solder joint temperature, the wire core side temperature and the pressing force, and outputs the heating power to the heating and pressing part 11 and the display content to the temperature display unit 21.

[0062] In this embodiment, the temperature control evaluation unit can be implemented by a microcontroller embedded in the grip 2.

[0063] It should be noted that the welding clamp in this embodiment is usually used as a welding tool in a complete set of terminal manufacturing processes in actual operation.

[0064] As a supporting environment, after the cable is put into the cabinet, it can be fixed by the fixing buckle. The fixing buckle has a unidirectional tightening and one-button release opening and closing tooth buckle structure.

[0065] The soldering terminals can be made of copper tin-plated parts, one end of which is a patch-type contact surface adapted to the curvature of the armor and pre-coated with solder and flux, and the other end is a crimp connector for crimping the external grounding wire.

[0066] After welding, the standard head can be restored by inserting the insulation protection layer consisting of a cold-shrink insulation outer layer, an inner filler layer, and an inner sealing support layer. The outer insulation can be restored by removing the inner sealing support layer.

[0067] The aforementioned fixing latch, welding terminal, and insulation protection layer restoration standard head are components used in conjunction with this invention and are used to illustrate the application scenarios of the welding clamp. They do not constitute a limitation on the scope of protection of this invention.

[0068] Example 2

[0069] This embodiment illustrates the overall process of the welding control method for secondary cable terminations, which is executed by the temperature control evaluation unit of Embodiment 1.

[0070] like Figure 2 As shown, the welding control methods include:

[0071] Collect data on solder joint temperature, wire core side temperature, and clamping force;

[0072] Adjust the heating power according to the solder joint temperature to make the solder joint temperature track the target temperature;

[0073] The welding qualification is assessed based on the solder joint temperature, clamping force, and solder phase transformation characteristics, and a qualification prompt or resoldering prompt is output.

[0074] The heating power is cut off when the core side temperature reaches the core insulation temperature resistance threshold or the core side temperature rise rate exceeds the rate threshold.

[0075] The entire welding control process proceeds in three stages: preheating, fusion, and termination.

[0076] During the preheating stage, the heating clamping part 11 is heated at full power, and after the welding point temperature reaches the preheating temperature, it enters the fusion stage.

[0077] During the welding stage, the weld joint temperature is maintained to track the target temperature and the effective heat input of the welding stage is accumulated;

[0078] When the effective heat input reaches the target heat input and the rate of change of the weld point temperature is lower than the platform stability threshold and continues for the set time, the process enters the termination stage and cuts off the heating power, while outputting a weld qualification conclusion.

[0079] In addition to the above stages, a high-priority core protection judgment is superimposed: at any time, as long as the core side temperature reaches the core insulation temperature resistance threshold, or the core side temperature rise rate exceeds the rate threshold, the heating power is immediately cut off and an alarm is triggered.

[0080] Record the temperature on the core side as The judgment condition is: or ,in, The temperature threshold of the wire core insulation. This is the upper limit of the heating rate on the core side.

[0081] The temperature resistance threshold of the conductor insulation is determined based on the long-term temperature resistance capability of the conductor insulation: when the cable sheath is made of polyvinyl chloride, The temperature should not exceed 105℃; for example, 95℃, 100℃, and 105℃ are acceptable. When the cable sheath is made of cross-linked polyethylene... The temperature should not exceed 130℃; for example, 115℃, 125℃, or 130℃ are acceptable.

[0082] Example 3

[0083] Based on Example 2, this embodiment describes the specific method of adjusting the heating power according to the solder joint temperature, namely, adaptive temperature control with online identification and dead zone compensation.

[0084] Output power of heating core 111 Proportional-integral-derivative control closed-loop tracking of target temperature Its basic form is: Among them, feedforward term Used to compensate for steady-state heat dissipation The outer diameter of the cable armor. For ambient temperature, , The heat dissipation coefficient is calibrated according to the fixture structure. , These are proportional, integral, and differential gains, respectively. The temperature deviation after dead zone compensation. For time.

[0085] Unlike the common practice of tuning gain by looking up a table based on wire diameter, the gain in this embodiment is tuned based on the thermal time constant obtained through online identification. The solder joint thermal process is modeled as a first-order process with pure time delay, and discretized into a difference equation with regression form. , in, For discrete sampling sequence number, For the first The solder joint temperature at each sampling time. For the regression vector, The parameter vector to be identified, , These are the coefficients to be identified for the first-order plus pure time delay model.

[0086] Online parameter estimation using recursive least squares with forgetting factor : ; ,in, To identify prediction errors, To identify the gain vector, To identify the covariance matrix (in relation to heating power) In contrast, the covariance matrix is... express), This is the forgetting factor, with a value range of 0.95 to 0.99, such as 0.95, 0.97, and 0.99.

[0087] Obtained from identification Inverse calculation of thermal time constant , The sampling period is used; the gain is then tuned to: , in, , As the reference gain, This is the reference thermal time constant.

[0088] There is a conduction hysteresis between the heating core 111 and the solder joint temperature measuring unit 13. To address this, a Smith predictor is superimposed, and the hysteresis-free predicted temperature is fed into the control loop. , in, To eliminate hysteresis in the predicted temperature, To identify the hysteresis-free output of the model, This refers to the conduction dead time.

[0089] To ensure the feasibility of the identification process, updates will only be made during the preheating phase. At this point, the heating power continues to be fully activated; once the welding stage begins, the process freezes. And preserve the covariance matrix This helps avoid recognition drift caused by insufficient incentives.

[0090] Target temperature The required temperature for complete solder wetting is specified for soldering copper terminals. The value range is from 250℃ to 300℃, for example, 250℃, 270℃, and 300℃.

[0091] By adjusting the gain through online identification, the soldering clamp can stabilize the solder joint temperature to near the target temperature for solder joints with different wire diameters, different armor materials, and moisture conditions, thus suppressing cold solder joints caused by insufficient temperature and burns caused by excessive temperature.

[0092] Example 4

[0093] Based on Example 2, this embodiment describes the specific method for evaluating welding qualification, namely, the multimodal fusion of confidence adaptive weight and phase transition inflection point detection.

[0094] The weld acceptance rate is determined by a combination of four modes: solder joint temperature, clamping force, effective heat input, and solder wetting phase transition. First, the fusion stage is defined (solder joint temperature is above the solder liquidus line). The effective heat input within the ) serves as a proxy for wettability: ,in, For effective heat input, This refers to the liquidus temperature of solder. , These represent the start and end times of the welding phase, respectively. This indicates taking the positive part; that is, if the value inside the parentheses is positive, it is taken as itself, and if it is negative, it is taken as zero.

[0095] The three sub-indicators—heat input compliance, clamping force stability, and temperature plateau duration scaling—are taken from the following values: They are respectively: , in, , These are respectively: heat input compliance, clamping force stability, and temperature plateau duration scaling. For target heat input, This is the bandwidth factor, with a value ranging from 0.2 to 0.3, for example, it can be 0.2, 0.25, or 0.3. For indicator functions, , These represent the average and fluctuation of the clamping force, respectively. , These are the lower and upper limits of the acceptable clamping force range. This serves as a normalized scale for the fluctuation of the clamping force. The duration for which the solder joint temperature remains within the target temperature range. The target duration for the platform.

[0096] Infiltration completion The temperature rise stagnation is determined based on the absorption of latent heat of phase transition by molten solder. Let the temperature rise rate be... First, noise is suppressed by moving average or median filtering. Then, during the welding stage, the presence of time-related noise is detected. Make (Warmth is nearing a standstill) and (Still heating), and requires that the pause last no less than ;

[0097] By depth or duration of stagnation Mapped to immersion completion using the sigmoid function: , in, To ensure the completion of the soaking process, For the rate of temperature rise, The threshold for the rate of temperature rise used to determine stagnation. The shortest duration of stagnation, To determine the minimum heating power required when the heating stops, For the depth or duration of stagnation, , The center and scale of the sigmoid function. This is the sigmoid function.

[0098] Confidence levels of each modality The signal-to-noise ratio within the fusion window is estimated; the greater the jitter in the sensing channel, the lower the confidence level. (Subscript) Indicates the first Each modality. Weights in prior weights. Based on the confidence level, it adapts and sets a lower limit for the weights. To prevent a certain mode from being completely suppressed; normalized weighted composite welding qualification rate : , in, For the first Confidence level of each modality For the first Prior weights for each modality, For the first The modal-normalized weights As the lower limit of the weight, For welding qualification. Prior weight. The preferred ratio is Weight lower limit 0.05 is acceptable.

[0099] When welding qualification Reaching the qualified threshold Output a pass / fail message if the condition is met; otherwise, output a re-welding message indicating the missing mode and the pass / fail threshold. 0.8 is acceptable.

[0100] Example 5

[0101] This embodiment provides two specific operational examples to illustrate the application of the above-mentioned welding clamp and welding control method under different wire diameters and different sheath materials, and to demonstrate the implementation of each parameter within its value range.

[0102] The first assignment example involves fabricating a secondary cable terminal inside a protection cabinet of a 220kV substation.

[0103] Cable armor outer diameter =12mm, ambient temperature =25℃, soldering terminals are tin-plated copper surface mount terminals, target temperature =270℃, solder liquidus line =200℃. Temperature sampling period of temperature control evaluation unit (22) =20ms, force sampling period 20ms, display refresh rate 5Hz; temperature signal is denoised by first-order low-pass filter, temperature rise rate After 5-point sliding median filtering, the force signal is calibrated at zero point when powered on.

[0104] The remaining parameters are set as follows: preheating temperature =180℃, core insulation temperature resistance threshold =105℃ (PVC sheath), upper limit of heating rate =15℃ / s, platform stability threshold =2℃ / s, platform duration 1.0s; temperature control reference gain =8、 =1.2、 =0.5, reference thermal time constant =8s, forgetting factor =0.97, conduction dead zone =0.3s, initial value of covariance matrix Prior weights for pass / fail =0.4:0.2:0.15:0.25, lower weight limit =0.05, bandwidth factor =0.25, target heat input =600℃·s, platform target duration =2s, stagnation threshold =3℃ / s =0.3s ( (Maximum output power of heating core 111), sigmoid parameter =0.4、 =0.15, acceptable threshold =0.8.

[0105] During operation, clamp head 1 is aligned with the designated position on the armor and pressed down, and the heat insulation insert is inserted into the inside of the armor.

[0106] After power-on, the system enters the preheating stage, with the heating element 111 heating at full power. During this stage, the thermal process is identified online using the recursive least squares method. have to ≈7.2s, adjusted accordingly ≈7.2、 ≈1.33. After the solder joint temperature rises to 180℃ (approximately 2 to 3 seconds), the welding process begins, and the solder joint immediately freezes. And preserve the covariance matrix The identification will no longer be updated.

[0107] During the welding stage, the conduction dead zone is compensated by the Smith predictor. Then, the solder joint temperature is maintained at 270℃±5℃ to continuously accumulate effective heat input. And by the filtered The inflection point of phase transition stagnation was detected. When Reaching 600℃·s and plateauing If the temperature is less than 2℃ / s for 1 second, the process will terminate normally, and the termination phase will begin, during which the welding qualification will be calculated.

[0108] Substitute the sub-indicators and their weights: ≈610℃·s, ≈0.90; the average clamping force falls within the acceptable range and fluctuates little. ≈0.85; Platform duration ≈2s, The value was taken as 0.80 based on the fluctuations at the end of the platform; a significant stagnation of phase transition was detected. Larger ≈0.88. Confidence levels for each modality. ≈0.95 ≈0.85 ≈0.90 ≈0.95, the weight after normalization ≈0.41 ≈0.18 ≈0.15 ≈0.26, all higher than the lower limit of the weight. Weighted composition ≈ 0.87≥0.8, temperature display unit 21(23) shows qualified. Temperature of the entire conductor side. The peak temperature was approximately 70°C, but the core protection cutoff was not triggered.

[0109] If, during the welding stage, the insulation insert is not properly inserted, and the core temperature rapidly rises to 105°C or its heating rate exceeds 15°C / s, heating will be immediately cut off and an alarm will sound, prompting repositioning. If the signal-to-noise ratio of a certain mode drops sharply (e.g., due to interference with the force sensing channel), its confidence level will automatically decrease and its weight will be reduced to the lower limit to avoid misjudgment. If termination occurs... If the standard is not met, the phase transformation stagnation inflection point is not detected, or the clamping force fluctuates too much, the welding qualification rate is less than 0.8, indicating re-welding and marking the missing mode.

[0110] Example 2 of the assignment involves a scenario where multiple cables are centrally arranged in a power distribution room. The cables are cross-linked polyethylene sheathed, with an armored outer diameter of [missing information]. =20mm.

[0111] Accordingly, the temperature resistance threshold of the wire core insulation is taken as =130℃. Online identification during the preheating stage. ≈13s (larger wire diameter has greater heat capacity), based on which the system automatically adjusts to a larger value. With smaller , feed forward term Follow With the increase in temperature, the target heat input $Q^*$ is correspondingly increased to approximately 900℃·s, and the preheating and welding times are extended accordingly, while the rest of the process and criteria remain unchanged. This example demonstrates that, without changing tools or resetting the entire set of parameters, online identification can automatically adapt to different wire diameters and armor materials.

[0112] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A welding clamp for secondary cable terminations, characterized in that, include: Pliers head (1) and handle (2); The clamp head (1) is provided with a heating and pressing part (11), a solder joint temperature measuring unit (13) and a wire core side temperature measuring unit (14). The heating and pressing part (11) is used to heat and press the soldering terminal. The solder joint temperature measuring unit (13) is located on the side of the clamp head (1) near the solder joint. The wire core side temperature measuring unit (14) is located on the side of the clamp head (1) near the wire core. The grip (2) is provided with a temperature control evaluation unit and a force sensing unit. The force sensing unit is located on the pressing force transmission path of the heating and pressing part (11). The temperature control evaluation unit is electrically connected to the heating and pressing part (11), the solder joint temperature measuring unit (13), the wire core side temperature measuring unit (14), and the force sensing unit, respectively.

2. The secondary cable termination welding clamp according to claim 1, characterized in that, The clamp head (1) is divided into an upper part and a lower part. The heating and pressing part (11) is located in the upper part of the clamp head (1). The lower part of the clamp head (1) is provided with a heat insulation and temperature measuring part (12). The heat insulation and temperature measuring part (12) is provided with a heat insulation insert for inserting into the inner side of the cable armor. The core side temperature measuring unit (14) is located on the side of the heat insulation and temperature measuring part (12) near the core. The core side temperature measuring unit (14) is embedded in the side of the heat insulation insert near the core.

3. The secondary cable termination welding clamp according to claim 1, characterized in that, The grip (2) is divided into a lower part and an upper part. The lower part of the grip (2) is an operating handle (23) for controlling the opening and closing and pressing of the pliers head (1). The upper part of the grip (2) is provided with a temperature display unit (21), a temperature control evaluation unit and a temperature control start / stop switch (22). The power supply of the welding pliers is introduced from the tail end of the grip (2).

4. A welding control method for secondary cable terminations, characterized in that, Includes the following steps: The temperature of the solder joint, the temperature of the wire core side, and the clamping force are collected. The temperature of the solder joint is the temperature at the point where the welding terminal is welded to the cable armor. The temperature of the wire core side is the temperature on one side of the cable core. The clamping force is the clamping force applied to the welding terminal. Adjust the heating power according to the solder joint temperature to make the solder joint temperature track the target temperature; The welding qualification is evaluated based on the solder joint temperature, the clamping force, and the solder phase transformation characteristics, and a qualification prompt or resoldering prompt is output. The heating power is cut off when the temperature on the core side reaches the core insulation temperature resistance threshold or when the temperature rise rate on the core side exceeds the rate threshold.

5. The welding control method for secondary cable terminations according to claim 4, characterized in that, The steps for adjusting the heating power include: Identify the thermal process parameters of the weld joint online; The temperature control parameters for tracking the target temperature are adjusted based on the thermal process parameters.

6. The welding control method for secondary cable terminations according to claim 5, characterized in that, The online identification specifically includes: The thermal time constant of the solder joint thermal process is identified using the recursive least squares method with a forgetting factor; The gain of proportional-integral-derivative control is tuned according to the thermal time constant; The online identification is updated during the preheating phase and frozen during the welding phase. The Smith predictor is used to compensate for the conduction hysteresis between heating and temperature measurement.

7. The welding control method for secondary cable terminations according to claim 4, characterized in that, The steps for assessing the weld quality include: The welding qualification is calculated by multimodal fusion based on the solder joint temperature, the clamping force, the effective heat input during the welding stage, and the solder phase transformation characteristics. The qualified prompt is output when the welding qualification reaches the qualified threshold; otherwise, the re-welding prompt is output.

8. The welding control method for secondary cable terminations according to claim 7, characterized in that, The multimodal fusion method includes: The degree of wetting completion is determined by the stagnation of temperature rise caused by the latent heat of the solder molten phase transition. Determine the heat input compliance, clamping force stability, and temperature plateau duration scaling; The welding qualification is synthesized by adaptively weighting the heat input compliance, the clamping force stability, the temperature plateau duration scaling, and the wetting completion according to their respective confidence levels.

9. The welding control method for secondary cable terminations according to claim 4, characterized in that, The welding control method includes a preheating stage, a fusion stage, and a termination stage; After the preheating stage is completed and the temperature is raised to the preheating temperature at full power, the welding stage begins. During the welding phase, the weld joint temperature is maintained to track the target temperature and effective heat input is accumulated. When the effective heat input reaches the target heat input, and the rate of change of the solder joint temperature is lower than the platform stability threshold, and this continues for a set duration, the process transitions to the termination phase.

10. The welding control method for secondary cable terminations according to claim 4, characterized in that, The temperature resistance threshold of the core insulation is no higher than 105°C when the cable sheath is made of polyvinyl chloride and no higher than 130°C when the cable sheath is made of cross-linked polyethylene.

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