A lifting device for testing wire ropes

Abstract

This invention relates to the field of wire rope inspection, and more particularly to a lifting device for wire rope inspection. It includes a loading host, a tension sensor for acquiring wire rope tension values, and a detection probe for acquiring damage signals. Its key feature is the inclusion of a constant lift-off follow-up system. This system comprises a micro-motion platform, a lift-off value sensor, and a controller. The controller receives the real-time tension acquired by the tension sensor and obtains a feedforward predicted value based on a preset wire rope structural mechanics model. The controller receives the actual distance fed back by the lift-off value sensor and compares it with a target constant lift-off value to obtain a feedback correction amount. The controller integrates the feedforward predicted value and the feedback correction amount to generate and output a total radial displacement command to the micro-motion platform, maintaining a target constant lift-off value distance from the wire rope surface in real time. By actively and precisely maintaining a constant lift-off value between the probe and the wire rope surface throughout the loading process, interference from the dynamic loading process itself on the detection signal is eliminated.

Description

Technical Field

[0001] This invention relates to the field of wire rope testing, and more particularly to a lifting device for wire rope testing. Background Technology

[0002] As a critical load-bearing component, the safety of wire ropes is of paramount importance. Dedicated load testing is the core method for detecting internal damage that only becomes apparent under stress, and typically consists of an existing frame, clamping mechanism, and drive mechanism to form the loading host.

[0003] Because fatigue fracture of the steel wires inside a wire rope often exhibits a "stress opening and closing effect," the fracture surface is forced to open only under sustained high tension, bending, or alternating loads, revealing the characteristic signals of the defect. These critical defects represent the true gaps in the remaining strength of the wire rope and are potential culprits for sudden fracture accidents during lifting operations.

[0004] Therefore, to obtain the true service condition of the wire rope, real-time testing must be conducted under dynamic conditions of continuous loading and unloading. If the existing "static tensioning, shutdown testing" mode is used, the wire rope is clamped at both ends and tension is applied, while scanning is performed using probes such as magnetic flux leakage and ultrasound in a static state. However, dynamic loading itself introduces fatal testing interference: the wire rope undergoes elastic diameter contraction and axial elongation under tension, accompanied by radial high-frequency vibration caused by tension fluctuations. This results in constant changes in the lift-off value between the testing probe and the wire rope surface. Fluctuations in the lift-off value directly cause baseline drift, sensitivity inaccuracy, and defect feature distortion in the testing signal, leading to misjudgment and quantitative deviation of defects. Therefore, the existing "static tensioning, shutdown testing" mode can only reflect the residual damage state of the wire rope when unloaded or statically held, and cannot capture critical defects that only appear under dynamic stress. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a lifting device for wire rope testing; by actively and precisely maintaining a constant lift value between the probe and the wire rope surface throughout the entire loading process, the interference of the dynamic loading process itself on the detection signal is eliminated.

[0006] The objective of this invention can be achieved through the following technical solutions: A lifting device for inspecting wire ropes includes a loading host, a tension sensor for acquiring wire rope tension values, and a detection probe for acquiring damage signals; it also includes a constant lift-off follow-up system; the constant lift-off follow-up system includes a micro-motion platform, a lift-off value sensor, and a controller; the micro-motion platform is used to mount and drive the detection probe to move radially and axially along the wire rope; the lift-off value sensor is located on the detection probe and is used to measure the actual distance between the probe and the wire rope surface in real time; the controller is electrically connected to the tension sensor, the lift-off value sensor, and the spatial micro-motion platform; the controller has a built-in preset wire rope structural mechanics model and a target constant lift-off value table; The controller receives the real-time tension collected by the tension sensor; and based on a preset wire rope structural mechanics model, obtains feedforward predicted values ​​including the radial shrinkage and axial elongation of the wire rope; the controller receives the actual distance fed back by the lift-off value sensor and compares it with the target constant lift-off value to obtain a feedback correction amount; the controller integrates the feedforward predicted value and the feedback correction amount to generate and output a total radial displacement command to the micro-motion platform to drive the detection probe to maintain the target constant lift-off value distance from the wire rope surface in real time.

[0007] As a further technical solution of the present invention, the micro-motion platform includes a radial guide mechanism, which is a rigid guide platform with a flexible hinge, and one end of the micro-motion platform is connected to an external radial drive source; the external radial drive source is a voice coil motor.

[0008] As a further technical solution of the present invention, the lift-off value sensor is an eddy current displacement sensor, and its sensing end face is installed coplanarly with the magnetic end face of the detection probe.

[0009] As a further technical solution of the present invention, the micro-motion platform is equipped with a high-resolution grating ruler; the controller measures the axial displacement of the platform in real time through the grating ruler; and calculates the predicted axial elongation and the axial displacement together to establish the real-time position of the detection probe in the absolute length coordinate system of the wire rope.

[0010] As a further technical solution of the present invention, the mechanical model of the wire rope structure is a nonlinear composite stiffness model. Based on the twisting structure, nominal diameter and metal cross-sectional area of ​​the wire rope, a function correspondence table of "tension-internal stress redistribution-macroscopic radial shrinkage" is constructed. The model is pre-calibrated by tensile test and can be corrected online during the detection process by using the deviation between the actual spacing and the predicted radial shrinkage.

[0011] As a further technical solution of the present invention, the detection probe is an annular magnetic flux leakage detection ring, which surrounds the outer periphery of the steel wire rope.

[0012] As a further technical solution of the present invention, the detection probe is an electromagnetic ultrasonic probe, which performs acoustic coupling with the surface of the wire rope in a non-contact manner.

[0013] As a further technical solution of the present invention, the clamping mechanism in the loading host is a non-destructive load-equalizing clamp with a flexible medium pad, and a sealed fluid pressure pad is provided between the clamping surface and the wire rope.

[0014] As a further technical solution of the present invention, a dynamic constant lift-off value detection method is also included, applied to the above-mentioned device, comprising the following steps: S1: Preparation: Set up the loading host, place the steel wire rope to be tested on the loading host and collect the data of the steel wire rope to be tested by the sensor; S2: During the process of the loading host applying a continuously changing tensile load to the wire rope, the tension value is collected in real time by the tension sensor; the tension value is input into the preset wire rope structural mechanics model, and the model feeds forward to calculate the radial shrinkage and axial elongation of the wire rope at the current and next moments. S3: The lift-off value sensor measures the actual distance between the current detection probe and the surface of the wire rope, compares the actual distance with the preset target constant lift-off value, and generates a feedback radial correction amount; S4: The controller merges the radial shrinkage variable calculated by the feedforward with the feedback radial correction amount to generate a total radial displacement command; drives the spatial micro-motion platform to execute the total radial displacement command, so that the detection probe always maintains the target constant lift value with the wire rope surface throughout the entire dynamic loading process.

[0015] As a further technical solution of the present invention, the wire rope structural mechanical model is corrected in real time during the detection process. Specifically, the steady-state deviation between the actual distance measured by the lift-off value sensor and the target constant lift-off value within a certain period is used as the model correction amount to adaptively adjust the slowly varying parameters in the wire rope structural mechanical model. The slowly varying parameters include the surface wear amount and temperature expansion amount of the wire rope.

[0016] The beneficial effects of this invention are as follows: 1. By adding a constant lift-off follow-up system consisting of a micro-motion platform, a lift-off value sensor, and a controller, the controller uses a preset wire rope structural mechanics model to convert the real-time collected tension value into a feedforward prediction value. Simultaneously, it integrates the feedback correction value from the lift-off value sensor to drive the micro-motion platform to actively follow the deformation of the wire rope surface. This ensures that the detection probe maintains a constant target distance from the wire rope surface throughout the continuous loading and unloading process. This solves the problem of lift-off value instability caused by the shrinkage of the wire rope's elastic diameter, axial elongation, and tension fluctuations during dynamic loading. It breaks the traditional understanding that "dynamic loading inevitably interferes with the detection signal," ensuring that the detection signal baseline no longer drifts, the sensitivity remains consistent, and the defect characteristics are no longer distorted. This allows for the accurate and stable capture of critical internal defects in the wire rope that only open under dynamic stress, improving the accuracy and reliability of the safety assessment of the remaining life of the wire rope.

[0017] 2. By pre-calibrating and online adaptively correcting the nonlinear composite stiffness model, the stability of the feedforward prediction accuracy is ensured during long-term testing. This enables wire rope testing to move from the traditional "static stop sampling" mode to a "dynamic real-time monitoring" mode, achieving a complete record of the entire damage propagation process of the wire rope under continuous loading and unloading conditions. Attached Figure Description

[0018] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the constant lift-off follow-up system of the present invention; Legend: 1. Frame; 2. Wire rope; 3. Micro-motion platform; 4. Annular leakage magnetic field detection ring; 5. Lift-off value sensor; 6. Controller. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0021] During the loading and testing of wire rope 2, the wire rope 2 will undergo elastic diameter shrinkage and axial elongation under tension, accompanied by radial high-frequency vibration caused by tension fluctuations. This causes the lift-off value between the detection probe and the surface of the wire rope 2 to change continuously. The fluctuation of the lift-off value directly causes baseline drift of the detection signal, inaccurate sensitivity and distortion of defect features. This is the fundamental reason why existing technologies can only perform "static shutdown detection" and cannot capture critical defects under dynamic loading.

[0022] In this regard, refer to Figures 1-2This embodiment provides a lifting device for detecting a wire rope 2, including a loading host, a tension sensor, a detection probe, and a constant lift-off follow-up system. The loading host consists of an existing frame 1, a clamping mechanism, and a driving mechanism. The constant lift-off follow-up system consists of a micro-motion platform 3, a lift-off value sensor 5, and a controller 6. The micro-motion platform 3 is used to carry and drive the detection probe to move radially and axially along the wire rope 2. The lift-off value sensor 5 is integrated on the detection probe to measure the real distance between the probe and the surface of the wire rope 2 in real time. The controller 6 has a built-in structural mechanics model of the wire rope 2 and a target constant lift-off value. The controller 6 receives the real-time tension value collected by the tension sensor and predicts the radial shrinkage and axial elongation through model feedforward. At the same time, it receives the real distance fed back by the lift-off value sensor 5 and compares it with the target value to obtain the feedback correction amount. Then, it merges the feedforward predicted value and the feedback correction amount to generate a total radial displacement command to drive the micro-motion platform 3 to move. By setting up the above, the problem of lift-off value instability during dynamic loading is solved from the root, breaking the traditional understanding that "dynamic loading will inevitably interfere with detection". This ensures that the detection probe maintains a constant distance from the surface of the wire rope 2 throughout the entire process of continuous loading and unloading. The detection signal baseline is stable and the sensitivity is consistent, which can truly capture the critical defects inside the wire rope 2 that only open under dynamic stress.

[0023] Because the diameter change and radial jitter of the wire rope 2 during dynamic loading are high-frequency, micrometer-level transient processes, conventional motors coupled with ball screws or rack and pinion drives suffer from transmission backlash and frictional hysteresis. Ordinary ball guides also exhibit creep and backlash under micro-motion conditions, resulting in insufficient response bandwidth to keep up with these microsecond-level position changes in real time. Therefore, in one embodiment, the radial drive source connecting the micro-motion platform 3 to the external system uses a voice coil motor, and the radial guide mechanism uses a rigid guide platform with flexible hinges. A voice coil motor is a direct-drive motor that directly converts electrical signals into linear motion, without intermediate transmission links, and features zero backlash, high response, and high acceleration. The flexible hinge guide platform utilizes the elastic deformation of the material to achieve frictionless, backlash-free precision guidance, with high rigidity and zero hysteresis. This existing equipment solves the problem of traditional drive and guide mechanisms being unable to precisely follow the high-frequency radial transient displacement of the wire rope 2 due to backlash, friction, and insufficient response, achieving microsecond-level response and micrometer-level tracking accuracy for the radial position changes of the wire rope 2, thus ensuring the engineering feasibility of constant lift-off value control from a hardware perspective.

[0024] In a closed-loop control system, if the measuring end face of the displacement sensor used for feedback is not on the same plane as the actual working end face of the detection probe, the measured distance value will contain a fixed or varying bias error. The decision made by the controller 6 based on this erroneous feedback will cause the constant lift-off control to fail. Therefore, in one embodiment, the lift-off sensor 5 is an eddy current displacement sensor. Its sensing end face is precisely mounted so that it is completely coplanar with the magnetic end face of the detection probe. The eddy current sensor uses a high-frequency magnetic field to induce eddy currents on the surface of the wire rope 2 to measure the distance non-contactly. The coplanar mounting ensures that the sensor measures the direct distance from the magnetic end face of the probe to the surface of the wire rope 2. Through this setup, the spatial bias error between the displacement sensor and the working end face of the probe is eliminated, ensuring the authenticity and accuracy of the feedback signal. This allows the "true distance" obtained by the controller 6 to accurately represent the actual lift-off value from the working end face of the detection probe to the surface of the wire rope 2, providing a reliable signal reference for closed-loop control.

[0025] During dynamic loading, the wire rope 2 will continuously elongate under stress. If the detection probe only follows radially but remains stationary axially, the elongation of the wire rope 2 will cause the relative contact point between the probe and the rope surface to continuously slip. This not only results in axial geometric mismatch, weakening the radial compensation effect, but also makes it impossible to determine the specific length position of the wire rope 2 corresponding to the current detection signal, leading to a loss of defect positioning accuracy. To address this, in one embodiment, a high-resolution grating ruler is integrated into the micro-motion platform 3 to measure the axial displacement of the platform in real time. The controller 6 obtains the predicted axial elongation of the wire rope 2 from the structural mechanics model and reads the actual axial displacement of the platform from the grating ruler, and performs joint calculations. When the wire rope 2 slides axially relative to the probe due to elongation, the grating ruler accurately records the slippage. Combined with the predicted elongation, the axial position of each detection signal is accurately marked in the absolute length coordinate system of the wire rope 2. By setting up the above, a constant radial lift value is achieved while completing a zero-slip spatial positioning scan of the entire length of the wire rope 2, ensuring a one-to-one correspondence between the detection signal and the actual length position of the wire rope 2, and solving the problems of unknown probe axial slippage and inaccurate defect spatial positioning caused by the elongation of the wire rope 2 under dynamic loading.

[0026] The steel wire rope 2 is a composite material made of multiple steel wires wound in a specific twisting structure. Its radial shrinkage under tension is not a simple material Poisson effect, but rather originates from the internal stress redistribution between the strands and structural compression, exhibiting a complex nonlinear relationship. If a simple linear model is used for estimation, the feedforward compensation amount itself will be incorrect, and the feedback loop will bear an excessive correction burden, leading to system oscillation or lag. To address this, in one embodiment, the structural mechanics model of the steel wire rope 2 adopts a nonlinear composite stiffness model. This model is based on the twisting structure, nominal diameter, and metal cross-sectional area of ​​the steel wire rope 2 under test. Through extensive tensile tests in the early stages, a functional correspondence table or multiple forms of relationship between "tension-internal stress redistribution-macroscopic radial shrinkage" is established and pre-stored in the controller 6 as the feedforward control core. During the detection process, the steady-state deviation between the measured spacing and the predicted radial shrinkage of the lift-off value sensor 5 is used to adaptively correct the model parameters online. To address the problem of feedforward compensation failure caused by inaccurate predictions in simple linear models, a nonlinear model based on the physical structure of the wire rope 2 and real physical experiments provides highly accurate feedforward predictions, reducing the correction pressure on the feedback loop and enabling the control system to maintain a constant lift value smoothly and accurately. It also has adaptability to different specifications of wire rope 2 and changes in long-term use.

[0027] Since magnetic flux leakage detection is the most commonly used method for damage detection of wire rope 2, it uses permanent magnets to locally magnetize the wire rope 2 to saturation. When defects such as broken wires or wear exist, magnetic lines of force escape from the surface, forming a leakage magnetic field that is picked up by magnetic sensitive elements. However, the intensity of the leakage magnetic signal is extremely sensitive to the lift-off value, and the attenuation of the magnetic field in air exhibits a strongly nonlinear relationship. The instability of the lift-off value directly leads to a decrease in the signal-to-noise ratio and distortion in defect quantification. To address this, in one embodiment, the detection probe uses a ring-shaped magnetic flux leakage detection ring 4. This ring consists of two sets of permanent magnets and a magnetic yoke forming a magnetic circuit, with a magnetic sensitive element array evenly distributed on the inner wall. The magnetic flux leakage detection ring surrounds the outer circumference of the wire rope 2, and a constant lift-off follow-up system keeps its magnetic end face at the target distance from the surface of the wire rope 2. This achieves stable and highly sensitive detection of internal and external damage throughout the continuous loading and unloading process of the wire rope 2; and solves the problems of baseline drift, increased noise, and distortion of defect features caused by lift-off value fluctuations in magnetic flux leakage detection under dynamic loading.

[0028] Electromagnetic ultrasound is a detection technique that directly excites and receives ultrasonic waves on the surface of a steel wire rope 2 using a bias magnetic field and eddy current coils. Its transduction efficiency decreases exponentially with the increase of the lift-off value between the probe and the measured surface. During dynamic loading, the shrinkage and vibration of the steel wire rope 2's diameter cause high-frequency fluctuations in the lift-off value, resulting in drastic changes in ultrasonic emission and reception energy, and fluctuating defect echo height, leading to a complete collapse of quantitative accuracy. To address this, in one embodiment, an electromagnetic ultrasonic probe is used. This probe faces the surface of the steel wire rope 2 with a preset small gap in a non-contact manner. Ultrasonic waves are generated in the skin layer of the steel wire rope 2 using high-frequency, high-current pulses. A constant lift-off servo system strictly maintains this non-contact gap at the target value. The constant lift-off value ensures stable emission and reception efficiency of the electromagnetic ultrasound, accurately reflects the defect size in the defect echo amplitude, and maintains a stable beam incident angle. This allows for the acquisition of stable and repeatable ultrasonic detection signals during dynamic loading of the steel wire rope 2, making it particularly suitable for detecting fatigue cracks in internal steel wires. This study aims to solve the problems of severe oscillations in transducer efficiency and distortion of defect echo amplitude caused by lift-off value fluctuations in electromagnetic ultrasound under dynamic loading.

[0029] In the loading test of wire rope 2, the clamping mechanism must firmly clamp both ends of the wire rope 2 to transmit large-tonnage tensile force. However, traditional rigid wedge or pressure plate clamps will generate extremely high local contact stress and indentations on the surface of the wire rope 2 when clamping. These clamping damages themselves can be captured by leakage magnetic field or ultrasonic probes as "defect signals" and form false indications, which seriously interfere with the judgment of the actual service damage of the wire rope 2. To address this, in one embodiment, the clamping mechanism adopts a non-destructive load-equalizing clamp based on a flexible medium pad. A sealed fluid pressure pad is set between the clamping surface of the clamp and the wire rope 2, and the inside is filled with magnetorheological fluid or hydraulic oil. When the clamp applies pressure, the pressure inside the fluid pressure pad is evenly transmitted, so that the clamping force is evenly distributed on the circumference of the wire rope 2 and over a certain length, eliminating local hard contact stress peaks. This invention addresses the problem of false defect signals introduced by traditional rigid clamps, achieving reliable clamping and tension transmission of the wire rope 2 without causing any mechanical damage to the surface of the wire rope 2. It ensures that all signals collected within the detection area originate from the actual service damage of the wire rope 2, thereby reducing the false alarm rate caused by false defects.

[0030] Relying solely on hardware devices without a corresponding specific control method and process is insufficient to achieve the goal of dynamic constant lift-off value detection. Therefore, this embodiment provides a method for dynamic constant lift-off value detection of a wire rope 2, applied to the aforementioned device. The specific steps include: S1: Preparation: Set up the loading host, place the steel wire rope 2 to be tested on the loading host and collect the data of the steel wire rope 2 to be tested by the sensor; S2: The loading host applies a continuous tensile load to the wire rope 2, and the tension sensor synchronously collects the real-time tension value; the controller 6 inputs the tension value into the structural mechanics model and feeds forward to calculate the radial shrinkage and axial elongation at the current and next moment; S3: The actual distance between the lift-off value sensor 5 and the surface of the wire rope 2 is measured by the actual detection probe. The controller 6 compares it with the target lift-off value to generate a feedback radial correction amount. S4: Controller 6 merges the feedforward radial shrinkage variable and the feedback radial correction amount to generate a total radial displacement command; drives the micro-motion platform 3 to execute the total radial displacement command so that the detection probe always follows the surface of the wire rope 2. During this dynamic process, damage signals from the detection probe are simultaneously acquired to obtain complete damage evolution data for the entire continuous loading and unloading process. By organically integrating feedforward prediction and feedback correction, and simultaneously completing the complete signal acquisition operation steps, the various components of the device work together to achieve true synchronization between the loading and detection processes. The composite control of rapid feedforward coarse adjustment and precise feedback fine adjustment ensures both response speed and steady-state accuracy. The damage expansion information of wire rope 2 from zero load to full load and then to breakage is completely recorded, solving the problem of the lack of a method for specifically implementing force-position cross-domain linkage control to stably obtain complete damage signals of wire rope 2 during continuous dynamic loading, and providing data support for analyzing its true load-bearing capacity and remaining life.

[0031] The surface condition of the wire rope 2 changes slowly over long-term use. For example, the wire surface may experience wear, coating peeling, or millimeter-level thermal expansion due to changes in ambient temperature. These slow changes cause the pre-calibrated structural mechanics model to gradually deviate from the true "tension-contraction" relationship. If left uncorrected, the error in the feedforward prediction value will accumulate over time, ultimately affecting the long-term stability of the constant lift-off value control. Therefore, in this embodiment, the controller 6 performs real-time correction of the structural mechanics model of the wire rope 2 during the detection process. Specifically, the controller 6 continuously monitors the actual distance measured by the lift-off value sensor 5. When the system is in a stable loading phase, if a non-transient, continuous steady-state deviation is found between the measured distance and the target constant lift-off value, it is determined that the deviation originates from the drift of the slowly varying parameters of the model. This steady-state deviation is used as a model correction amount to adaptively adjust the slowly varying parameters in the model, such as the wear amount and temperature expansion amount of the wire rope 2 surface, so that the model output approximates the true value again. This constant lift-off value control can adapt to slow time-varying factors such as wire rope 2 wear and temperature drift, ensuring that the device maintains high-precision lift-off value control during long-term continuous testing tasks. It solves the problem of decreased accuracy of the pre-calibration model and degradation of feedforward control effect caused by slow changes in the surface condition and environment of the wire rope 2 under long-term testing conditions. The online adaptive correction mechanism gives the testing system the ability to self-calibrate.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A lifting device for inspecting wire ropes, comprising a loading host, a tension sensor for acquiring wire rope tension values, and a detection probe for acquiring damage signals; characterized in that: It also includes a constant lift-off follow-up system; the constant lift-off follow-up system includes a micro-motion platform, a lift-off value sensor, and a controller; the micro-motion platform is used to install and drive the detection probe to move radially and axially along the wire rope; the lift-off value sensor is located on the detection probe and is used to measure the actual distance between it and the surface of the wire rope in real time; the controller is electrically connected to the tension sensor, the lift-off value sensor, and the micro-motion platform respectively; the controller has a built-in preset wire rope structural mechanics model and a target constant lift-off value table; The controller receives the real-time tension collected by the tension sensor; and based on a preset wire rope structural mechanics model, obtains feedforward predicted values ​​including the radial shrinkage and axial elongation of the wire rope; the controller receives the actual distance fed back by the lift-off value sensor and compares it with the target constant lift-off value to obtain a feedback correction amount; the controller integrates the feedforward predicted value and the feedback correction amount to generate and output a total radial displacement command to the micro-motion platform to drive the detection probe to maintain the target constant lift-off value distance from the wire rope surface in real time.

2. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The micro-motion platform includes a radial guide mechanism, which is a rigid guide platform with a flexible hinge. One end of the micro-motion platform is connected to an external radial drive source, which is a voice coil motor.

3. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The lift-off value sensor is an eddy current displacement sensor, and its sensing end face is mounted coplanarly with the magnetic end face of the detection probe.

4. The lifting equipment for steel wire rope testing according to claim 2, characterized in that: The micro-motion platform is equipped with a high-resolution grating ruler; the controller measures the axial displacement of the platform in real time through the grating ruler; and calculates the predicted axial elongation and the axial displacement together to establish the real-time position of the detection probe in the absolute length coordinate system of the wire rope.

5. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The structural mechanics model of the wire rope is a nonlinear composite stiffness model. Based on the twisting structure, nominal diameter, and metal cross-sectional area of ​​the wire rope, a function correspondence table of "tension-internal stress redistribution-macroscopic radial shrinkage" is constructed. The model is pre-calibrated through tensile tests and corrected online during the testing process using the deviation between the actual spacing and the predicted radial shrinkage.

6. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The detection probe is an annular magnetic flux leakage detection ring, which surrounds the outer circumference of the steel wire rope.

7. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The detection probe is an electromagnetic ultrasonic probe, which performs acoustic coupling with the surface of the wire rope in a non-contact manner.

8. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The clamping mechanism in the loading host is a non-destructive load-equalizing clamp with a flexible medium pad, and a sealed fluid pressure pad is provided between the clamping surface and the wire rope.

9. A method for detecting dynamic constant lifting value, applied to the lifting equipment for testing wire ropes as described in any one of claims 1-8, characterized in that: Includes the following steps: S1: Preparation: Set up the loading host, place the steel wire rope to be tested on the loading host and collect the data of the steel wire rope to be tested by the sensor; S2: During the process of the loading host applying a continuously changing tensile load to the wire rope, the tension value is collected in real time by the tension sensor; The tension value is input into a preset wire rope structural mechanics model, and the model feeds forward to calculate the radial shrinkage and axial elongation of the wire rope at the current and next moments. S3: The lift-off value sensor measures the actual distance between the current detection probe and the surface of the wire rope, compares the actual distance with the preset target constant lift-off value, and generates a feedback radial correction amount; S4: The controller integrates the radial shrinkage variable calculated by the feedforward with the feedback radial correction amount to generate a total radial displacement command; it drives the micro-motion platform to execute the total radial displacement command so that the detection probe maintains the target constant lift value with the wire rope surface throughout the entire dynamic loading process.

10. The lifting equipment for steel wire rope testing according to claim 1, characterized in that: The wire rope structural mechanics model is corrected in real time during the detection process. Specifically, the steady-state deviation between the actual distance measured by the lift-off value sensor and the target constant lift-off value within a certain period is used as the model correction amount to adaptively adjust the slowly varying parameters in the wire rope structural mechanics model. The slowly varying parameters include the surface wear and temperature expansion of the wire rope.

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