Pressure-displacement dual-parameter closed-loop control-based crimping pliers and control method thereof

Abstract

The application belongs to the technical field of electrical connection, and particularly relates to a pressure contact pliers based on pressure displacement double-parameter closed-loop control and a control method thereof. The pressure contact pliers comprises a mechanical execution mechanism, a double-parameter sensing system and a controller. The mechanical execution mechanism comprises a jaw, a hydraulic cylinder, a piston and a return spring. The double-parameter sensing system comprises a pressure sensor and a displacement sensor. The controller stores a standard pressure-displacement curve library and performs curve comparison and closed-loop control based on real-time collected double-parameter signals. The control method realizes instant determination and closed-loop control of pressure contact quality through establishment of a standard curve library, real-time double-parameter collection, real-time curve comparison and abnormal classification processing, and is suitable for reliable pressure contact of copper-aluminum dissimilar metals in the field of electrical connection.

Description

Technical Field

[0001] This invention belongs to the field of electrical connection technology, and in particular to a crimping clamp and its control method based on pressure-displacement dual-parameter closed-loop control. Background Technology

[0002] In industries such as power, petrochemicals, and rail transportation, cable conductor connections are a common engineering challenge. Copper-aluminum dissimilar metal connections are prone to electrochemical corrosion and joint loosening due to differences in electrode potential and thermal expansion coefficients, especially in humid environments or under temperature cycling. Existing crimping technologies suffer from the following drawbacks: uncontrollable crimping parameters with force fluctuations exceeding ±10%; lack of process monitoring methods, relying solely on visual inspection or destructive testing after crimping, making it impossible to determine whether the oxide film has been effectively punctured; high risk of weld damage; and difficulty in data traceability. While existing technologies include hydraulic clamps with pressure displays, they cannot be used in conjunction with displacement parameters to analyze the integrity of the crimping process, and a mapping relationship between pressure-displacement curves and crimping quality has not been established, thus hindering closed-loop quality control.

[0003] Therefore, how to achieve dual-parameter closed-loop control of the crimping process, so that the crimping parameters are controllable, the crimping quality can be judged in real time, the weld damage can be actively protected, and the crimping data can be completely traced, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing crimping technology has uncontrollable crimping parameters, large force fluctuations, lack of process monitoring means, inability to judge crimping quality in real time, easy damage to welds, and inability to trace crimping data, making it difficult to achieve closed-loop control of crimping quality.

[0005] The technical solution adopted by this invention to solve its technical problem is: a crimping clamp based on pressure-displacement dual-parameter closed-loop control, including a mechanical actuator, a dual-parameter sensing system, and a controller. The mechanical actuator includes jaws, a hydraulic cylinder, a piston, and a return spring. The dual-parameter sensing system includes a pressure sensor for real-time acquisition of crimping force signals and a displacement sensor for real-time acquisition of crimping displacement signals. The controller stores a standard pressure-displacement curve library. The controller receives real-time signals from the pressure sensor and the displacement sensor and generates a real-time pressure-displacement curve. The real-time pressure-displacement curve is compared with the standard pressure-displacement curve library, and a control signal is output based on the comparison result.

[0006] Furthermore, the jaws are replaceable to accommodate terminals and wires of different specifications.

[0007] Furthermore, the controller employs an embedded microprocessor, runs a real-time operating system, and has a built-in wireless communication module for communicating with a host computer or mobile terminal.

[0008] Furthermore, it also includes a human-machine interface, which includes a display module and buttons. The display module is used to display real-time pressure-displacement curves, pressing parameters, and judgment results, while the buttons are used to set product specifications and operating instructions.

[0009] Furthermore, it also includes an audible and visual alarm device, which includes a buzzer and multi-level indicator lights, used to issue audible and visual alarm signals when there is an abnormality in the crimping.

[0010] Furthermore, it also includes a power management system that uses a dual power supply mode of plug-in and lithium battery.

[0011] Furthermore, the controller's stored standard pressure-displacement curve library contains standard curves for different specifications of terminal-lead combinations. Each standard curve includes the initial crimping force F0 and the peak crimping force F. p Effective pressing displacement S e The slope K of the pressure holding section, the rebound amount ΔS, and the acceptance judgment envelope.

[0012] Furthermore, the controller's comparison includes curve standardization, feature point extraction, envelope determination, and anomaly classification.

[0013] Furthermore, the abnormality classification and handling include low pressure, high pressure and automatic stop of crimping, insufficient displacement, excessive displacement, and abnormal curve.

[0014] The beneficial effects of this invention are as follows: By acquiring dual-parameter signals in real time through pressure and displacement sensors, and combining them with the standard pressure-displacement curve library built into the controller for real-time comparison and deviation judgment, closed-loop quality control of the crimping process is achieved, controlling the crimping force fluctuation within ±5%, which is significantly better than the ±10% of the prior art; through real-time curve comparison and anomaly classification processing, the crimping quality is judged immediately, eliminating the need for destructive testing after crimping, thus improving detection efficiency and reliability; through automatic stopping of crimping when the pressure is too high, audible and visual alarms when displacement and pressure are abnormal, and complete data recording and traceability functions, the risk of weld damage is avoided, and full data traceability of the crimping process is achieved. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 This is a schematic diagram comparing the standard PD curve and the real-time curve.

[0018] Figure 3 This is a flowchart of the closed-loop control algorithm.

[0019] Figure 4This is a flowchart of the standard curve library creation process.

[0020] Explanation of reference numerals in the attached drawings: 100. Mechanical actuator; 110. Jaw; 120. Hydraulic cylinder; 130. Piston; 200. Dual-parameter sensing system; 210. Pressure sensor; 220. Displacement sensor; 300. Controller; 310. Embedded microprocessor; 320. Wireless communication module; 330. Storage module; 400. Human-machine interface; 410. Display module; 420. Button; 500. Audible and visual alarm device; 510. Buzzer; 520. Multi-level indicator light; 600. Power management system. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited thereto.

[0022] like Figures 1-4 As shown, the crimping clamp of the present invention includes a mechanical actuator 100, a dual-parameter sensing system 200, a controller 300, a human-machine interface 400, an audible and visual alarm device 500, and a power management system 600. The mechanical actuator 100 includes jaws 110, a hydraulic cylinder 120, a piston 130, and a return spring. The jaws 110 are replaceable and can be replaced according to the specifications of the terminals and wires. The dual-parameter sensing system 200 includes a pressure sensor 210 installed inside the hydraulic cylinder 120 or on the crimping path and a displacement sensor 220 installed near the piston 130. The pressure sensor 210 is used to acquire crimping force signals in real time, and the displacement sensor 220 is used to acquire crimping displacement signals in real time. The pressure sensor 210 can be a strain gauge type or a piezoelectric sensor with a range covering 0 to 60 kN and a resolution of not less than 0.01 kN; the displacement sensor 220 can be a magnetostrictive or wire-type displacement sensor with a range covering 0 to 50 mm and a resolution of not less than 0.01 mm.

[0023] The controller 300 employs an embedded microprocessor 310, running a real-time operating system, responsible for data acquisition, curve comparison, and output control. The controller 300 has a built-in wireless communication module 320 for communication with a host computer or mobile terminal, which can use Bluetooth or WiFi modules to achieve data transmission, facilitating remote storage and traceability of crimping data. The controller 300's storage module 330 pre-stores a standard pressure-displacement curve library, which is designed for different terminal-wire combinations, such as TL50 terminals with 50mm... 2 Aluminum wire or TL70 terminal with 70mm 2 Copper wires, etc., were established through extensive experiments. Each standard curve includes the initial crimping force F0, the peak crimping force F... p Effective pressing displacement S eThe parameters include the slope K of the pressure holding section, the springback amount ΔS, and the acceptance envelope. The standard curve is established as follows: at least 100 samples of the same specification are selected and subjected to pressing tests under standard conditions, recording complete PD curves; statistical analysis is performed on all curves to calculate the mean curve and standard deviation; the mean ± 1.5 times the standard deviation is taken as the acceptance envelope. This envelope represents the allowable deviation range, with a typical value of ±8%.

[0024] The execution process of the closed-loop control algorithm of controller 300 is as follows: Before the crimping officially begins, the operator selects the specifications of the terminals and wires through the button 420 on the human-machine interface 400. Controller 300 then imports the corresponding standard curve from the standard pressure-displacement curve library. After the crimping begins, pressure sensor 210 and displacement sensor 220 collect crimping force and displacement signals in real time at a sampling frequency of not less than 1kHz. Controller 300 receives these real-time signals and generates a real-time pressure-displacement curve. The controller's comparison algorithm includes four steps: First, curve standardization, using time axis normalization and speed compensation algorithms to eliminate the influence of operating speed differences on the curve shape; Second, feature point extraction, identifying the starting point, oxide film puncture inflection point, peak point, holding pressure start point, holding pressure end point, and rebound point on the curve; Third, envelope determination, calculating the deviation distance between each sampling point on the real-time curve and the standard mean curve, and determining whether each sampling point is within the qualified judgment envelope range; Fourth, anomaly classification processing, outputting the corresponding alarm signal or control command based on the judgment result.

[0025] The specific rules for anomaly classification and handling are as follows: When the real-time peak pressure F p Less than the standard peak pressing force F p0 When the pressure reaches 85%, it is determined to be too low, and the alarm device outputs an audible and visual alarm signal indicating "insufficient crimping force," prompting a check of the hydraulic system or the compatibility of the terminals and wires; when the real-time peak crimping force F... p Greater than the standard peak pressure force F p0 When the pressure reaches 115%, it is determined to be too high. The controller 300 immediately sends a stop signal to automatically stop the crimping. At the same time, the buzzer 510 emits a continuous alarm, and the multi-level indicator light 520 displays red to prevent overpressure damage to the terminals and wires. When the real-time effective crimping displacement S... e Less than the standard effective pressing displacement S e0 When the displacement reaches 90%, it is determined to be insufficient, and an alarm message "Crimping incomplete" is displayed, suggesting re-crimping; when the real-time effective crimping displacement S... e Greater than the standard effective pressing displacement S e0 When the displacement is 110%, it is determined to be too large, and an alarm message "overpressure risk" is issued. When the slope K of the pressure holding section deviates from the standard slope K0 of the pressure holding section by more than ±10%, it is determined to be an abnormal curve, and an alarm message "crimping abnormal" is issued. It is recommended to check the condition of the crimping mold or material.

[0026] In terms of control principles, the core of this invention lies in establishing a mapping relationship between the pressure-displacement dual parameters and the pressing quality. The peak pressing force F of the pressure-displacement curve... p The contact resistance of the crimped joint is directly related to the peak crimping force. When the peak crimping force is within 85% to 115% of the standard value, the contact resistance is stable below 50 μΩ, indicating that sufficient plastic deformation and good metallic bonding have been achieved between the metals. The slope K of the holding pressure section reflects the plastic flow characteristics of the material during the holding pressure stage. When the slope of the holding pressure section is within ±10% of the standard value, the pull-out force of the crimped joint reaches the optimal value, indicating that sufficient mechanical interlocking and interface bonding strength have been formed between the terminal and the wire. The springback ΔS reflects the degree of elastic recovery after pressure release. The springback of normal crimping is between 0.2 and 0.5 mm. Too little springback may mean that overpressure has caused excessive hardening of the material, while too much springback indicates insufficient crimping and insufficient contact pressure.

[0027] The human-machine interface 400's display module 410 uses an LCD screen to display the pressure-displacement curve, current crimping force, current displacement, crimping time, and judgment result in real time during the crimping process. After crimping is completed, the display module 410 displays the final judgment conclusion as either "qualified" or "specific abnormality type," and records the complete PD curve data, timestamp, operator information, and terminal wire specifications of this crimping in the storage module 330, supporting the storage and retrieval of at least 1000 historical records. The audible and visual alarm device 500 includes a buzzer 510 and multi-level indicator lights 520. During normal crimping, the indicator lights display green; during abnormalities, they display yellow or red depending on the level of abnormality. Yellow represents low-level abnormalities such as low pressure or insufficient displacement, while red represents high-level abnormalities such as high pressure, automatically stopping the process, and accommodating the intermittent or continuous buzzing of the buzzer 510. The power management system 600 supports both plug-in and lithium battery dual power supply modes. The lithium battery capacity is sufficient for continuous operation for more than 8 hours, allowing use in field environments without external power.

[0028] The crimping pliers of this invention include three progressive implementation methods: In the basic version, the mechanical structure is modified from a standard hydraulic pliers body, and the controller 300 realizes real-time curve display and post-crimping judgment functions; the advanced version adds a servo valve control system to the basic version, and the controller 300 automatically fine-tunes the hydraulic pressure of the hydraulic cylinder 120 according to the deviation between the real-time curve and the standard curve to achieve more precise closed-loop control with a response time of less than 50ms; the networked version adds a network function to the advanced version, and uploads crimping data to a cloud server through the wireless communication module 320 to realize centralized data management and remote quality monitoring of multiple crimping pliers.

[0029] The crimping pliers of this invention operate as follows: The operator installs the corresponding replaceable jaws 110 according to the specifications of the terminals and wires to be crimped, selects the product specifications via button 420, and the controller 300 loads the corresponding standard curve. After the operator starts crimping, the hydraulic cylinder 120 drives the piston 130 to close the jaws 110, and the pressure sensor 210 and displacement sensor 220 collect data in real time. During the crimping process, the first inflection point appears on the curve when the oxide film is punctured, followed by the plastic forming stage. The force value continues to rise to its peak value and then enters the pressure holding stage. After pressure is released, there is a certain amount of springback. The controller 300 completes the closed-loop judgment of the entire crimping process, displays and records the results. If an abnormality is detected, the operator can take corresponding measures based on the alarm prompts, such as checking the hydraulic system, changing the terminal specifications, or adjusting the crimping parameters.

Claims

1. A crimping clamp based on pressure-displacement dual-parameter closed-loop control, comprising a mechanical actuator (100), a dual-parameter sensing system (200), and a controller (300), characterized in that: The mechanical actuator (100) includes a jaw (110), a hydraulic cylinder (120), a piston (130), and a return spring; the dual-parameter sensing system (200) includes a pressure sensor (210) for real-time acquisition of pressing force signals and a displacement sensor (220) for real-time acquisition of pressing displacement signals; the controller (300) stores a standard pressure-displacement curve library, the controller (300) receives the real-time signals from the pressure sensor (210) and the displacement sensor (220) and generates a real-time pressure-displacement curve, compares the real-time pressure-displacement curve with the standard pressure-displacement curve library, and outputs a control signal based on the comparison result.

2. The crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: The jaws (110) are replaceable and can be used to adapt to terminals and wires of different specifications.

3. The crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: The controller (300) uses an embedded microprocessor (310) and runs a real-time operating system. The controller (300) has a built-in wireless communication module (320) for communicating with a host computer or mobile terminal.

4. A crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: It also includes a human-machine interface (400), which includes a display module (410) and buttons (420). The display module (410) is used to display real-time pressure-displacement curves, pressing parameters and judgment results, and the buttons (420) are used to set product specifications and operation instructions.

5. A crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: It also includes an audible and visual alarm device (500), which includes a buzzer (510) and a multi-level indicator light (520) for issuing an audible and visual alarm signal when the crimping is abnormal.

6. A crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: Also includes A power management system (600) is provided, which adopts a dual power supply mode of plug-in and lithium battery.

7. A crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: The controller (300) stores a standard pressure-displacement curve library containing standard curves for different specifications of terminal-wire combinations. Each standard curve includes initial crimping force F0, peak crimping force Fp, effective crimping displacement Se, holding pressure slope K, springback amount ΔS, and acceptance judgment envelope.

8. A crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 1, characterized in that: The comparison of the controller (300) includes curve standardization, feature point extraction, envelope determination, and anomaly classification processing.

9. A crimping clamp based on pressure-displacement dual-parameter closed-loop control according to claim 8, characterized in that: abnormal The classification and processing include low pressure, high pressure and automatic stopping of crimping, insufficient displacement, excessive displacement and abnormal curve.

10. A control method for a crimping clamp based on pressure-displacement dual-parameter closed-loop control, employing a crimping clamp based on pressure-displacement dual-parameter closed-loop control as described in any one of claims 1 to 9, characterized in that... Includes the following steps: Step 1: Establish a standard pressure-displacement curve library. For different specifications of terminal-wire combinations, establish standard curves including acceptance criteria envelopes through experiments. Step 2: Collect pressure and displacement signals in real time during the crimping process using pressure and displacement sensors. Step 3: The controller generates real-time pressure-displacement curves based on the collected pressure and displacement data. Step 4: Compare the real-time pressure-displacement curves with the corresponding standard curves in the standard pressure-displacement curve library, and perform curve standardization, feature point extraction, envelope determination, and anomaly classification. Step 5: Based on the comparison results, if the result is deemed qualified, a qualified signal will be output; if the result is deemed abnormal, an appropriate audible and visual alarm signal will be output according to the type of abnormality, and the pressing will be automatically stopped when the pressure is too high.

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