Double magnetic loop decoupling and three-dimensional magnetic induction reconstruction steel wire rope on-line detection system and method

Abstract

The present application relates to steel wire rope detection technical field, disclose a double magnetic circuit decoupling and three-dimensional magnetic sensing reconstruction steel wire rope on-line detection system and method, including: double magnetic circuit magnetization unit, three-dimensional magnetic sensing scanning unit, ultrasonic trigger and positioning unit and signal processing unit;Double magnetic circuit magnetization unit is used for applying physical decoupling composite magnetic field to steel wire rope, respectively outputting saturated magnetization field suitable for metal cross section area loss detection and high gradient magnetic flux leakage field suitable for local defect detection;Three-dimensional magnetic sensing scanning unit is used for synchronously collecting three-dimensional space vector data of defect magnetic flux leakage field;Ultrasonic trigger and positioning unit is used for detecting local defect abnormal signal, emitting and receiving ultrasonic guided wave based on magnetostrictive effect, and obtaining defect axial coordinates;Signal processing unit is used for receiving three-dimensional space vector data and axial coordinates, completing defect three-dimensional magnetic flux leakage image reconstruction, axial coordinate calibration and three-dimensional geometric profile inversion, and outputting detection results.

Description

Technical Field

[0001] This invention relates to the field of wire rope testing technology, specifically to an online testing system and method for wire ropes using dual magnetic circuit decoupling and three-dimensional magnetic reconstruction. Background Technology

[0002] As a core load-bearing component of critical equipment such as mine hoists, port cranes, bridge cables, and cableway transportation, the service condition of steel wire ropes directly determines the safety and reliability of equipment operation. Non-destructive testing technology based on the principle of electromagnetic induction has become the mainstream technique for steel wire rope defect detection due to its advantages such as non-contact operation, high detection speed, and continuous online monitoring. It primarily achieves a preliminary assessment of the degree of damage to steel wire ropes by monitoring two key characteristic quantities: local defects and loss of metal cross-sectional area.

[0003] However, existing electromagnetic nondestructive testing (NDT) technologies for wire ropes generally employ a single magnetic circuit excitation architecture. This architecture suffers from a fundamental conflict in excitation mechanisms: metal cross-sectional area loss detection requires the tested wire rope to reach deep magnetic saturation to establish a linear relationship between magnetic flux and cross-sectional area, while local defect detection requires a high-gradient unsaturated magnetic field to pick up weak leakage magnetic field signals. A single magnetic circuit cannot simultaneously accommodate these two drastically different magnetization requirements, leading to physical coupling and crosstalk between the two types of detection signals. This not only severely restricts the improvement of detection sensitivity and quantification accuracy but also limits existing technologies to outputting only one-dimensional time-domain detection waveforms, failing to acquire three-dimensional spatial morphology information and high-precision positioning information of defects. Consequently, it cannot meet the urgent needs of industrial sites for wire rope defect diagnosis and detailed maintenance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes an online detection system and method for steel wire ropes with dual magnetic circuit decoupling and three-dimensional magnetic induction reconstruction, which solves the aforementioned technical problems.

[0005] Firstly, an online detection system for steel wire ropes with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction is provided, including: The system comprises a dual magnetic circuit magnetization unit, a three-dimensional magnetic sensing scanning unit, an ultrasonic triggering and positioning unit, and a signal processing unit that is sequentially and coaxially arranged along the axial direction of the wire rope; The dual magnetic circuit magnetization unit is used to apply a physically decoupled composite magnetic field to the wire rope, and outputs a saturation magnetization field adapted to metal cross-sectional area loss detection and a high gradient leakage magnetic field adapted to local defect detection, respectively. The three-dimensional magnetic sensing scanning unit is used to synchronously acquire the three-dimensional spatial vector data of the defect leakage magnetic field generated by the high-gradient leakage magnetic field excitation; The ultrasonic triggering and positioning unit is used to receive the trigger signal from the signal processing unit, emit and receive ultrasonic guided waves based on the magnetostrictive effect, and obtain the axial coordinates of the defect. The signal processing unit is used to receive the three-dimensional spatial vector data and axial coordinates, complete the reconstruction of the three-dimensional magnetic flux leakage image of the defect, the calibration of the axial coordinates and the inversion of the three-dimensional geometric contour, and output the detection results.

[0006] Furthermore, the dual magnetic circuit magnetization unit includes an outer magnetic circuit, an inner magnetic circuit, and a magnetic isolation layer located between the outer magnetic circuit and the inner magnetic circuit, all coaxially nested. The external magnetic circuit is used to magnetize the wire rope to saturation, and the relationship between the total magnetic flux and the cross-sectional area of ​​the wire rope is established based on Ohm's law of magnetic circuits. The internal magnetic circuit is used to establish a high-gradient local magnetic field on the surface of the wire rope, and to excite local defects to generate a leakage magnetic field based on the magnetic dipole model. The magnetic isolation layer is used to decouple the physical signal sources of the outer magnetic circuit and the inner magnetic circuit.

[0007] Furthermore, the outer magnetic circuit includes a first permanent magnet and a first yoke, and the magnetic circuit of the outer magnetic circuit passes through the cross-section of the wire rope. The inner magnetic circuit includes a second permanent magnet, a second yoke, and a magnetic armature, and the inner magnetic circuit is distributed on the surface of the wire rope.

[0008] Furthermore, the three-dimensional magnetic sensing scanning unit includes an array of multiple triaxial magnetic sensors, a data acquisition subunit, and a circumferential scanning drive mechanism; The triaxial magnetic sensor integrates three orthogonal sensing axes to simultaneously measure the axial, normal, and circumferential components of the leakage magnetic field. The array is uniformly arranged along the circumference of the wire rope for high-resolution sampling of the circumferential morphology of the defect. The acquisition subunit is used to synchronously acquire the three-component magnetic field data of all sensors, and the sampling frequency is matched with the speed of the wire rope movement.

[0009] Furthermore, the ultrasonic triggering and positioning unit includes an ultrasonic probe, a pulse excitation subunit, and an echo processing subunit; The pulse excitation subunit is used to output a high-frequency pulse current to the ultrasonic probe when the signal processing unit detects that the local defect signal exceeds a preset threshold. The echo processing subunit is used to receive the ultrasonic echo reflected from the defect, measure the time difference between the transmitted pulse and the echo, and calculate the precise axial position of the defect based on the principle of pulse reflection.

[0010] Furthermore, the signal processing unit is configured to perform a three-dimensional magnetic flux leakage image reconstruction operation: The collected three-dimensional magnetic field data is organized into a three-dimensional data volume, in which the axial position is determined by the speed and time of the steel wire rope movement, and the circumferential position is determined by the sensor array layout. The magnetic field strength is converted into color values ​​by pseudo-color mapping, and three two-dimensional pseudo-color images of axial component, normal component and circumferential component are generated respectively. Among them, the axial component image reflects the axial polarity change of the defect, the normal component image reflects the depth and opening characteristics of the defect, and the circumferential component image reflects the circumferential extension range and twisting of the defect.

[0011] Furthermore, the signal processing unit solves the three-dimensional geometric contour of the defect based on the magnetic charge model and the finite element inverse problem. Its objective function includes error terms for the measured magnetic field and the forward calculated magnetic field, as well as regularization terms to ensure the smoothness of the solution. By minimizing the objective function using the conjugate gradient method, the magnetic charge distribution on the defect surface is obtained, and the three-dimensional geometric contour of the defect is reconstructed.

[0012] Furthermore, the signal processing unit is also configured to: The precise axial coordinates obtained by ultrasonic positioning are used to perform axial calibration on the three-dimensional magnetic flux leakage image, eliminating the cumulative positioning error caused by encoder slippage and wire rope creep. By integrating the amplitude and waveform characteristics of ultrasonic echoes with the characteristics of three-dimensional magnetic flux leakage images, and inputting them into a convolutional neural network classifier, intelligent identification and quantitative assessment of defect types can be achieved.

[0013] Secondly, a method for online detection of steel wire ropes based on dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction is provided, based on the online detection system for steel wire ropes based on dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction described in any of the preceding claims, including... In response to the activation trigger of online wire rope detection, a physically decoupled composite magnetic field is applied to the moving wire rope by a dual magnetic loop magnetization unit arranged coaxially along the wire rope axis, which respectively generates a saturation magnetization field suitable for metal cross-sectional area loss detection and a high gradient leakage magnetic field suitable for local defect detection. The magnetic flux change data of the external magnetic circuit is collected by a metal cross-sectional area loss detection sensor, and the three-dimensional spatial vector data of the defect leakage magnetic field is collected simultaneously by a triaxial magnetic sensor array. The collected data is preprocessed to obtain a complete detection dataset. The magnetic field signal in the detection data is monitored in real time. After identifying the abnormal signal of local defects, the ultrasonic triggering and positioning unit is controlled to transmit and receive ultrasonic guided waves based on the magnetostrictive effect. The precise axial coordinate of the defect is calculated by using the pulse reflection method. Three-dimensional magnetic flux leakage images are reconstructed based on three-dimensional spatial vector data, and image axial calibration is completed using ultrasonic positioning coordinates; Solve the inverse finite element problem based on the magnetic charge model to reconstruct the three-dimensional geometric contour of the defect; By integrating ultrasonic echo amplitude, waveform characteristics, and three-dimensional magnetic flux leakage image characteristics, intelligent identification of defect types can be achieved; By integrating all the test data, a comprehensive test report is generated, which includes the metal cross-sectional area loss curve, three-dimensional magnetic flux leakage image, three-dimensional contour map of the defect, and ultrasonic calibration coordinates, thus completing the online detection of wire rope defects.

[0014] The invention employing the above technical solution has the following advantages: 1. This invention addresses the excitation mechanism conflict problem existing in the current single magnetic circuit excitation architecture by coordinating the dual magnetic circuit magnetization unit, three-dimensional magnetic sensing scanning unit, ultrasonic triggering and positioning unit, and signal processing unit.

[0015] The dual magnetic circuit magnetization unit of the present invention can simultaneously adapt to the deep saturation magnetization requirements for metal cross-sectional area loss detection and the high gradient unsaturation magnetization requirements for local defect detection by applying a physically decoupled composite magnetic field. This effectively reduces the physical coupling crosstalk between the two types of detection signals, thereby improving detection sensitivity and quantization accuracy.

[0016] The three-dimensional magnetic induction scanning unit of this invention synchronously acquires three-dimensional spatial vector data of the defect leakage magnetic field. Combined with the three-dimensional leakage magnetic image reconstruction and three-dimensional geometric contour inversion of the signal processing unit, it is beneficial to overcome the limitations of traditional one-dimensional time-domain waveform analysis and obtain multi-dimensional spatial geometric information of the defect.

[0017] The ultrasonic triggering and positioning unit of the present invention obtains the precise axial coordinates of the defect based on the magnetostrictive effect. Combined with the axial coordinate calibration function of the signal processing unit, it can reduce the cumulative positioning error caused by encoder slippage and wire rope creep, thereby achieving more accurate quantitative assessment and positioning of wire rope defects. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the axial cross-sectional structure of the online detection system for steel wire rope with dual magnetic circuit decoupling and three-dimensional magnetic induction reconstruction of the present invention; Figure 2 This is a schematic diagram of the three-dimensional profile of the broken wire reconstructed by solving the inverse finite element problem in the online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction of the present invention. Figure 3 This is a schematic diagram illustrating the principle of ultrasonic pulse reflection ranging in the online detection system for steel wire ropes with dual magnetic loop decoupling and three-dimensional magnetic reconstruction of the present invention. Figure 4This is a waveform diagram of ultrasonic pulse reflection ranging in the online detection system for steel wire ropes with dual magnetic loop decoupling and three-dimensional magnetic reconstruction of the present invention. Figure 5 This is a flowchart of the online detection method for steel wire rope using dual magnetic circuit decoupling and three-dimensional magnetic reconstruction according to the present invention.

[0020] Figure label: 1. First permanent magnet; 2. First yoke; 3. Second permanent magnet; 4. Second yoke; 5. Magnetically conductive armature; 6. Magnetic isolation layer; 7. LMA sensor; 8. Steel wire rope; 9. Three-dimensional magnetic scanning sensor array. 10. Ultrasonic probe, 12. Circumferential scanning drive mechanism, 13. Axial length, 14. Radial depth, 15. Circumferential opening width, 16. Defect spatial orientation. Detailed Implementation

[0021] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0022] like Figures 1-5 As shown, the online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction of the present invention includes: The dual-magnetic-loop magnetization unit, the three-dimensional magnetic sensing scanning unit, the ultrasonic triggering and positioning unit, and the signal processing unit are arranged coaxially along the steel wire rope axis 8. The steel wire rope 8 passes through the central through hole of each unit. The signal output terminals of the three-dimensional magnetic sensing scanning unit and the ultrasonic triggering and positioning unit are connected to the signal input terminal of the signal processing unit. The trigger control terminal of the signal processing unit is connected to the control input terminal of the ultrasonic triggering and positioning unit.

[0023] Specifically, each unit works together to complete the magnetization and excitation of the wire rope, the acquisition of three-dimensional magnetic field data, the precise location of defects, the signal processing and output of results, and is fully adapted to the online uninterrupted detection scenario of the wire rope in motion.

[0024] The dual-magnetic-loop magnetization unit is used to apply a physically decoupled composite magnetic field to the wire rope 8, and outputs a saturation magnetization field adapted to metal cross-sectional area loss detection and a high-gradient leakage magnetic field adapted to local defect detection, respectively.

[0025] In this embodiment, the dual magnetic circuit magnetization unit includes an outer magnetic circuit, an inner magnetic circuit, and a magnetic isolation layer 6 located between the outer magnetic circuit and the inner magnetic circuit, all coaxially nested. The external magnetic circuit is used to magnetize the wire rope 8 to saturation. The relationship between the total magnetic flux and the cross-sectional area of ​​the wire rope 8 is established based on Ohm's law of magnetic circuits. The internal magnetic circuit is used to establish a high-gradient local magnetic field on the surface of the wire rope 8, and to excite local defects to generate a leakage magnetic field based on the magnetic dipole model. The magnetic isolation layer 6 is used to decouple the physical signal sources of the outer magnetic circuit and the inner magnetic circuit.

[0026] In this embodiment, the outer magnetic circuit includes a first permanent magnet 1 and a first yoke 2. The magnetic circuit of the outer magnetic circuit passes through the cross-section of the wire rope 8. The inner magnetic circuit includes a second permanent magnet 3, a second yoke 4 and a magnetic armature 5. The inner magnetic circuit is distributed on the surface of the wire rope 8.

[0027] Specifically, the dual-magnetic-loop magnetization unit adopts a coaxial nested cylindrical structure, which includes an outer magnetic loop, a magnetic isolation layer 6, and an inner magnetic loop from the outside to the inside. The magnetic isolation layer 6 is made of a high-resistivity non-magnetic material (such as copper alloy or aluminum alloy) with a thickness of 2-5 mm. It is used to block the magnetic coupling between the outer magnetic loop and the inner magnetic loop, thereby achieving physical decoupling of the two magnetic circuits.

[0028] The external magnetic circuit (LMA detection magnetic circuit) includes a ring-shaped first permanent magnet 1 and a first yoke 2. The first permanent magnet 1 is made of neodymium iron boron permanent magnet material, and the magnetization direction is axial; the first yoke 2 is made of electrical pure iron, which has high magnetic permeability and low coercivity. The magnetic circuit of the external magnetic circuit passes through the entire cross-section of the steel wire rope 8, magnetizing the entire steel wire rope 8 to a saturated state.

[0029] Through finite element simulation software optimization, a 2.0T saturation magnetic field is generated at the center of the wire rope 8 by the external magnetic circuit. The working principle of the external magnetic circuit is based on Ohm's law of magnetic circuits, and the total magnetic flux is linearly related to the effective metal cross-sectional area of ​​the wire rope 8. Its mathematical expression is:

[0030] in, Let be the total magnetic flux passing through the cross-section of the steel wire rope 8. The total magnetomotive force of the external magnetic circuit. The total magnetic reluctance of the external magnetic circuit. Coercivity is the force of a permanent magnet, characterizing the ability of a permanent magnet material to resist demagnetization. Let be the geometric length of the permanent magnet along the magnetization direction. This is the effective path length through which the magnetic flux travels inside the wire rope; For the working magnetic induction intensity of the wire rope material Differential permeability at this point This represents the effective cross-sectional area of ​​the magnetic circuit. It is assumed that the cross-sectional area of ​​the wire rope and the air gap are equivalent. It is the length of the single-sided air gap (the gap on one side between the permanent magnet and the surface of the wire rope). is the vacuum permeability.

[0031] Total magnetic reluctance It consists of the main body magnetic reluctance of the steel wire rope 8 and the air gap magnetic reluctance on both sides connected in series:

[0032] When the wire rope 8 suffers overall damage such as wear and reduction in cross-sectional area, the magnetic resistance of the wire rope 8 changes regularly, and the magnetic flux decreases accordingly. By collecting the change in magnetic flux, the signal processing unit can accurately calculate the real-time metal cross-sectional area loss of the wire rope 8, thus realizing the quantitative detection of the overall damage of the LMA.

[0033] The external magnetic circuit also includes an LMA sensor 7 (encircling coil), installed inside the first yoke 2 and arranged coaxially with the wire rope 8. The LMA sensor 7 is a multi-turn toroidal coil wound with enameled copper wire. It does not need to be in direct contact with the wire rope and operates based on the law of electromagnetic induction: when a changing magnetic flux passes through the coil, an induced electromotive force is generated at both ends of the coil, the magnitude of which is proportional to the rate of change of magnetic flux. The signal processing unit acquires this induced electromotive force signal, integrates it to obtain the total change in magnetic flux, and can then accurately calculate the real-time metal cross-sectional area loss rate of the wire rope, achieving quantitative detection of overall LMA damage.

[0034] The inner magnetic circuit (LF detection magnetic circuit) includes a ring-shaped second permanent magnet 3, a second yoke 4, and multiple circumferentially distributed magnetically conductive armatures 5. The second permanent magnet 3 is made of neodymium iron boron permanent magnet material, and its magnetization direction is radial; the magnetically conductive armatures 5 are made of electrical pure iron, with their tips pointing towards the surface of the steel wire rope 8. The magnetic circuit of the inner magnetic circuit is only distributed on the surface of the steel wire rope 8, establishing a high-gradient local magnetic field of more than 10T / m on the surface of the steel wire rope 8, which excites local defects to generate leakage magnetic fields.

[0035] The leakage magnetic field distribution of local defects is described using a magnetic dipole model, which equates the defect to a surface magnetic charge distributed along the circumference. The axial component H of the leakage magnetic field... x and normal component H y The parsing expression is:

[0036]

[0037] in, For spatial points The axial component of the magnetic field strength (along the length of the wire rope). For spatial points The normal component of the magnetic field strength (perpendicular to the surface of the wire rope, pointing towards the air side). The defect equivalent magnetization intensity characterizes the degree to which a ferromagnetic material is magnetized. Let be a spatial rectangular coordinate system, where Along the axial direction of the wire rope, Lateral along the cross section (parallel to the surface). Along the cross section normal ( >0 represents the air domain. For the defect in the axial position Equivalent half-width at (along) (Direction), can be followed Variations are used to describe variable cross-section defects. Pi For natural logarithm operations, It is the arctangent function.

[0038] The relationship between the magnetic flux density of the leakage magnetic field and the magnetic field strength is as follows:

[0039] The three-dimensional magnetic induction scanning unit is used to synchronously acquire three-dimensional spatial vector data of the defect leakage magnetic field generated by high gradient leakage magnetic field excitation.

[0040] In this embodiment, the three-dimensional magnetic sensing scanning unit includes an array of multiple triaxial magnetic sensors, a data acquisition subunit, and a circumferential scanning drive mechanism 12; The triaxial magnetic sensor integrates three orthogonal sensing axes to simultaneously measure the axial, normal, and circumferential components of the leakage magnetic field. The array is uniformly arranged along the eight circumferences of the steel wire rope for high-resolution sampling of the circumferential morphology of the defect; The acquisition subunit is used to synchronously acquire the three-component magnetic field data of all sensors, and the sampling frequency is matched with the movement speed of the wire rope 8.

[0041] Specifically, the three-dimensional magnetic sensing scanning unit is located downstream of the dual magnetic loop magnetization unit and includes a ring array of multiple triaxial magnetic sensors, a data acquisition subunit, and a circumferential scanning drive mechanism 12.

[0042] The triaxial magnetic sensor uses a TMR (tunneling magnetoresistive) sensor, integrating three orthogonal sensing axes, and can simultaneously measure the axial component B of the leakage magnetic field. x Normal component B y and circumferential component B z。 In this embodiment, the three-dimensional magnetic sensing sensor array 9 consists of 128 triaxial TMR chips, uniformly arranged circumferentially along the steel wire rope 8. The circumferential spacing between adjacent sensors is approximately 0.98° (not greater than 1°), enabling high-resolution sampling of the circumferential morphology of the defect. Multiple rows of arrays are arranged along the axial direction (x-axis) to form an m×n grid matrix. The acquisition subunit adopts a multi-channel parallel acquisition system with a sampling rate set to 10kHz. The sampling frequency is matched with the movement speed of the steel wire rope 8 to ensure that the axial sampling interval is not greater than 1mm and satisfies the Nyquist sampling theorem, enabling distortion-free reconstruction of the highest spatial frequency component of the defect.

[0043] The circumferential scanning drive mechanism 12 is used to drive the sensor array to rotate circumferentially around the steel wire rope 8, further improving the circumferential sampling resolution.

[0044] When the steel wire rope 8 moves at a constant speed of 1 m / s, the relationship between its axial position and the sampling time is as follows:

[0045] in, This refers to the axial position of the wire rope. The speed of the steel wire rope 8 relative to the sensor array. Sampling time.

[0046] The three-dimensional magnetic field vector data output by the three-dimensional magnetic induction scanning unit can be represented as:

[0047] in, The magnetic field strength vector is located in the upper right corner. This indicates the matrix transpose (converting a row vector into a column vector). denoted as the axial component of the magnetic flux density. For the normal component of the magnetic flux density, Let be the circumferential component of the magnetic flux density. , Spatial coordinates The horizontal position This refers to the axial position. For time, it is used to describe time-varying magnetic fields or to scan time-domain signals.

[0048] The ultrasonic triggering and positioning unit is used to receive the trigger signal from the signal processing unit, and to transmit and receive ultrasonic guided waves based on the magnetostrictive effect to obtain the axial coordinates of the defect.

[0049] In this embodiment, the ultrasonic triggering and positioning unit includes an ultrasonic probe 10, a pulse excitation subunit, and an echo processing subunit; The pulse excitation subunit is used to output a high-frequency pulse current to the ultrasonic probe 10 when the signal processing unit detects that the local defect signal exceeds a preset threshold. The echo processing subunit is used to receive the ultrasonic echo reflected from the defect, measure the time difference between the transmitted pulse and the echo, and calculate the precise axial position of the defect based on the pulse reflection method.

[0050] Specifically, the ultrasonic triggering and positioning unit is located downstream of the three-dimensional magnetic scanning unit and includes an ultrasonic probe 10, a pulse excitation subunit, and an echo processing subunit. The ultrasonic probe 10 is a magnetostrictive ultrasonic guided wave probe, which does not need to be in direct contact with the steel wire rope 8 and can transmit and receive ultrasonic guided waves at high speeds.

[0051] When the signal processing unit detects a local defect anomaly signal exceeding a preset threshold, it sends a trigger signal to the pulse excitation subunit. The pulse excitation subunit outputs a 200kHz high-frequency sinusoidal pulse current, the expression of which is:

[0052] in, For the instantaneous current of the high-frequency excitation pulse, For the excitation current amplitude, To excite the alternating current frequency, For time.

[0053] A high-frequency pulsed current excites the steel wire rope 8 to produce a magnetostrictive effect, which in turn excites an ultrasonic guided wave that propagates along the axial direction of the steel wire rope 8.

[0054] The relationship between magnetostrictive strain and excitation magnetic field strength is as follows:

[0055] in, It represents magnetostrictive strain (relative deformation). is the magnetostrictive strain coefficient (piezomagnetic coefficient), which characterizes the magnitude of strain excited by a unit magnetic field strength. To excite the magnetic field strength.

[0056] The propagation speed of the ultrasonic guided wave in the steel wire rope 8 is:

[0057] in, The phase velocity is the propagation speed of the ultrasonic guided wave along the axial direction of the steel wire rope. This refers to the elastic modulus (Young's modulus) of the steel wire rope material. This refers to the density of the steel wire rope material.

[0058] The echo processing subunit receives the ultrasonic echo reflected from the defect and measures the time between the transmitted pulse and the echo. The precise axial position of the defect is calculated based on the pulse reflection method:

[0059] in, This represents the axial one-way distance between the defect and the ultrasonic probe, i.e., the axial coordinate of the defect. The propagation speed of ultrasonic guided waves, This is the time difference (time of flight) between the transmitted pulse and the received defective echo.

[0060] This calculation method can effectively eliminate the cumulative positioning error caused by encoder slippage and wire rope creep.

[0061] The signal processing unit is used to receive three-dimensional spatial vector data and axial coordinates, complete the reconstruction of the three-dimensional magnetic flux leakage image of the defect, axial coordinate calibration and three-dimensional geometric contour inversion, and output the detection results.

[0062] In this embodiment, the signal processing unit is configured to perform a three-dimensional magnetic flux leakage image reconstruction operation: The collected three-dimensional magnetic field data is organized into a three-dimensional data volume, in which the axial position is determined by the speed and time of the steel wire rope 8, and the circumferential position is determined by the layout of the sensor array. The magnetic field strength is converted into color values ​​by pseudo-color mapping, and three two-dimensional pseudo-color images of axial component, normal component and circumferential component are generated respectively. Among them, the axial component image reflects the axial polarity change of the defect, the normal component image reflects the depth and opening characteristics of the defect, and the circumferential component image reflects the circumferential extension range and twisting of the defect.

[0063] In this embodiment, the signal processing unit solves the three-dimensional geometric contour of the defect based on the magnetic charge model and the finite element inverse problem. Its objective function includes the error term between the measured magnetic field and the forward calculated magnetic field, as well as the regularization term to ensure the smoothness of the solution. By minimizing the objective function using the conjugate gradient method, the magnetic charge distribution on the defect surface is obtained, and the three-dimensional geometric contour of the defect is reconstructed.

[0064] In this embodiment, the signal processing unit is further configured as follows: The precise axial coordinates obtained by ultrasonic positioning are used to perform axial calibration on the three-dimensional magnetic flux leakage image, eliminating the cumulative positioning error caused by encoder slippage and wire rope creep. By integrating the amplitude and waveform characteristics of ultrasonic echoes with the characteristics of three-dimensional magnetic flux leakage images, and inputting them into a convolutional neural network classifier, intelligent identification and quantitative assessment of defect types can be achieved.

[0065] Specifically, the signal processing unit is used to receive three-dimensional spatial vector data and axial coordinates, and to complete the reconstruction of the three-dimensional magnetic flux leakage image of the defect, axial coordinate calibration, three-dimensional geometric contour inversion and intelligent recognition.

[0066] The signal processing unit organizes the acquired three-dimensional magnetic field data into a three-dimensional data volume, where the axial dimension is determined by the sampling time and the speed of the steel wire rope 8, and the circumferential dimension is determined by the sensor array layout. The magnetic field strength is converted into color values ​​through pseudo-color mapping, generating three two-dimensional pseudo-color images for the axial, normal, and circumferential components, respectively. Axial component image: reflects the axial polarity change of the defect and is used to determine the type of defect (such as broken wire, wear). Normal component image: reflects the depth and opening characteristics of the defect, and is used to quantitatively assess the severity of the defect; Circumferential component image: reflects the extent and distortion of the defect in the circumferential direction, and is used to determine the circumferential distribution of the defect.

[0067] The signal processing unit uses the precise axial coordinates obtained from ultrasonic positioning to perform axial calibration on the three-dimensional magnetic flux leakage image, eliminating the cumulative positioning error caused by encoder slippage and wire rope creep. After calibration, the axial positioning error of the three-dimensional magnetic flux leakage image can be controlled within ±1mm.

[0068] The signal processing unit solves for the three-dimensional geometric profile of the defect based on a magnetic charge model and the inverse finite element problem. Given the magnetic charge distribution on the defect surface, the magnetic flux density at any observation point in space can be calculated using the following integral formula:

[0069] in, For space observation points The magnetic field strength vector at that location, The permeability of free space, It is the equivalent surface magnetic charge distribution surface (usually the defect end face). As the source The surface magnetic charge density at a given location is an unknown distribution to be determined. For observation point position vector, curved surface The position vector of the magnetically charged infinitesimal element; Let be the straight-line distance from the magnetic charge element to the observation point. curved surface The area of ​​the element is a micro-element.

[0070] When solving the inverse problem, the optimal magnetic charge distribution is obtained by minimizing the following objective function:

[0071] in, Let the objective function (cost function) have a minimum value that corresponds to the optimal magnetic charge distribution. Let be the surface magnetic charge density distribution function to be determined. This represents the total number of magnetic field measurement points. For measurement point serial numbers, For the first The measured magnetic flux density vector at each measuring point For the first The position vector of each measuring point To be based on the current The first one calculated by the forward integral formula Theoretical magnetic induction intensity vector at the measuring point The vector L2 norm square (sum of squares of all components) is used to quantize error. This is the regularization coefficient, used to balance fitting accuracy and solution smoothness. The spatial gradient of magnetic charge density, It is an L2 smoothing regularization term that constrains the spatial smoothness of the magnetic charge distribution and suppresses ill-conditioned solutions.

[0072] The first term of the objective function is the sum of squared residuals between the measured and calculated magnetic fields. The second term is a Tikhonov regularization term, used to constrain the smoothness of the solution and avoid computational distortion. The conjugate gradient method is used to minimize the objective function to obtain the optimal magnetic charge distribution. This allows for the reconstruction of the three-dimensional geometric contours of the defect.

[0073] The signal processing unit integrates the amplitude and waveform characteristics of ultrasonic echoes with the characteristics of three-dimensional magnetic flux leakage images, inputs them into a trained convolutional neural network classifier, and completes intelligent identification and quantitative assessment of defect types. It can distinguish between various defect types such as broken wires, wear, corrosion, and deformation.

[0074] In other embodiments, this embodiment takes a mine hoisting wire rope 8 with a diameter of 40mm and a structure of 6×19+FC as an example to detect a simulated wire breakage defect.

[0075] Dual magnetic circuit parameter design and finite element simulation: By optimizing the design using finite element simulation software, the external magnetic circuit generates a 2.0T saturated magnetic field at the center of the steel wire rope 8, and the internal magnetic circuit generates a magnetic field gradient of more than 10T / m on the surface.

[0076] 3D magnetic field scanning data acquisition: Hardware configuration: The 3D magnetic sensing sensor array 9 consists of 128 triaxial TMR chips, evenly arranged circumferentially (with a spacing of approximately 0.98°). Each chip can simultaneously measure B. x B y B z Components. The sampling rate is set to 10kHz.

[0077] Data Acquisition: The steel wire rope 8 moves at a speed of 1 m / s. As the defect passes beneath the sensor array, each chip records a three-component waveform that varies over time. The data from 128 chips are combined to form a four-dimensional dataset (t, z, B) containing the time axis (axial position), circumferential position, and the three components of the magnetic field. x B y B z ).

[0078] 3D image reconstruction: Data slicing: At time t=t0 (defect is facing the array center), extract all 128 channels B. y The value is used to obtain a circumferential magnetic field intensity curve B. y(z). According to the magnetic dipole formula, the curve presents two peaks with opposite polarities, and the distance between the peaks corresponds to the projection of the opening width of the broken wire in the circumferential direction.

[0079] Pseudo-color imaging: This involves capturing B values ​​at different times t (i.e., different axial positions x). y (z) curves are stacked to generate a B-shaped image. y A pseudo-color image. In the image, the horizontal axis is the circumferential z-axis, the vertical axis is the axial x-axis, and the color represents the magnetic field strength. A typical broken wire will appear as two symmetrical colored patches (one red positive peak and one blue negative peak).

[0080] Quantitative calculation: Based on the image, the center-to-center distance between the red and blue patches was measured to be 3 mm (corresponding to the width of the broken wire opening). The axial extension length of the patch was 5 mm (corresponding to the damage range of the broken wire along the axial direction of the wire rope).

[0081] Ultrasonic triggering and coordinate calibration: At time t0, B y When the signal peak exceeds a preset threshold, it triggers the ultrasonic probe 10 to emit a 200kHz ultrasonic guided wave. After receiving the echo, the time difference is measured. =78μs. The calibrated sound velocity c=5150m / s, the calculated ultrasonic positioning distance is: L = ½ × 5150 × 78 × 10 -6 =0.20085m≈201mm This coordinate is used to accurately calibrate the axial position in the 3D image and to correct errors that may be caused by encoder slippage (e.g., the original encoder reading is 195mm, and it is corrected to 201mm after calibration).

[0082] 3D contour reconstruction and report generation: The collected three-dimensional magnetic field data were substituted into the objective function, and the magnetic charge distribution was iteratively optimized through the inverse finite element method to finally reconstruct the three-dimensional profile of the broken wire. The results show that the broken wire is a single wire fracture with a smooth fracture surface. The axial length along the wire rope 8 is 13 mm, the radial depth is 14 mm (complete fracture), the circumferential opening width is 15 mm, and the defect spatial orientation 16 is 45° circumferentially.

[0083] Finally, the system outputs the following test report: LMA curve: shows the overall cross-sectional loss; 3D magnetic flux leakage image: B x B y B z Three pseudo-color images visually display the characteristics of the defects; 3D contour map of the defect: a 3D model of the broken wire reconstructed by the inverse problem algorithm; Defect list: Includes precise coordinates (201mm, 45° circumferential) after ultrasonic calibration, type (LF), and dimensions (5mm long × 3mm wide × 2mm deep).

[0084] In other embodiments, a method for online detection of steel wire ropes based on dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction is provided, including a system for online detection of steel wire ropes based on dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction as described above. In response to the activation trigger of the online detection of the wire rope 8, a physically decoupled composite magnetic field is applied to the moving wire rope 8 by a dual magnetic circuit magnetization unit arranged coaxially along the axial direction of the wire rope 8, which respectively generates a saturation magnetization field adapted to the detection of metal cross-sectional area loss and a high gradient leakage magnetic field adapted to the detection of local defects. The magnetic flux change data of the external magnetic circuit is collected by the metal cross-sectional area loss detection sensor, and the three-dimensional spatial vector data of the defect leakage magnetic field is collected simultaneously by the triaxial magnetic sensor array 9. The collected data is preprocessed to obtain a complete detection dataset. The magnetic field signal in the detection data is monitored in real time. After identifying the abnormal signal of local defects, the ultrasonic triggering and positioning unit is controlled to transmit and receive ultrasonic guided waves based on the magnetostrictive effect. The precise axial coordinate of the defect is calculated by using the pulse reflection method. Three-dimensional magnetic flux leakage images are reconstructed based on three-dimensional spatial vector data, and image axial calibration is completed using ultrasonic positioning coordinates; Solve the inverse finite element problem based on the magnetic charge model to reconstruct the three-dimensional geometric contour of the defect; By integrating ultrasonic echo amplitude, waveform characteristics, and three-dimensional magnetic flux leakage image characteristics, intelligent identification of defect types can be achieved; By integrating all the test data, a comprehensive test report was generated, which included the metal cross-sectional area loss curve, three-dimensional magnetic flux leakage image, three-dimensional contour map of the defect, and ultrasonic calibration coordinates, thus completing the online detection of 8 defects in the steel wire rope.

[0085] Specifically, system startup and initialization: In response to the startup trigger of the online detection of the wire rope 8, the dual magnetic circuit magnetization unit, three-dimensional magnetic sensing scanning unit, ultrasonic triggering and positioning unit and signal processing unit are initialized, and parameters such as sampling frequency, trigger threshold and ultrasonic excitation frequency are set.

[0086] Dual-magnetic-loop magnetization: A physically decoupled composite magnetic field is applied to the moving wire rope 8 through the dual-magnetic-loop magnetization unit. The outer magnetic loop magnetizes the wire rope 8 to a saturated state, generating a saturated magnetization field adapted to LMA detection. The inner magnetic loop establishes a high-gradient local magnetic field on the surface of the wire rope 8, generating a high-gradient leakage magnetic field adapted to LF detection.

[0087] Synchronous data acquisition: Magnetic flux variation data of the external magnetic circuit is acquired using an LMA detection sensor, while three-dimensional spatial vector data of the defect leakage magnetic field is simultaneously acquired using a triaxial magnetic sensor array. The acquired data undergoes preprocessing such as filtering and noise reduction to extract a complete detection dataset including metal cross-sectional area loss data and raw three-dimensional magnetic field data.

[0088] Abnormal signal monitoring and ultrasonic triggering: Real-time monitoring of the original three-dimensional magnetic field data in the complete detection dataset. When a local defect abnormal signal is detected and the preset triggering criteria are met (such as the magnetic field amplitude exceeding the threshold or the duration exceeding the set value), a trigger signal is sent to the ultrasonic triggering and positioning unit.

[0089] High-precision ultrasonic positioning: After receiving the trigger signal, the ultrasonic triggering and positioning unit emits ultrasonic guided waves based on the magnetostrictive effect and receives the echo reflected from the defect. By measuring the time difference between the emitted pulse and the echo, the precise axial coordinates of the defect are calculated based on the pulse reflection method.

[0090] 3D Magnetic Flux Leakage Image Reconstruction and Calibration: A 3D magnetic flux leakage image reconstruction model is constructed. Based on the original 3D magnetic field data, a 3D data volume is generated. Three 2D pseudo-color images (axial component, normal component, and circumferential component) are generated through pseudo-color mapping. The precise axial coordinates obtained by ultrasonic positioning are used to calibrate the 3D magnetic flux leakage image axially, eliminating accumulated positioning errors.

[0091] 3D Contour Inversion of Defects: A 3D contour inversion model of defects is constructed. Based on the magnetic charge model, the finite element inverse problem is solved by optimizing the objective function to obtain the magnetic charge distribution on the defect surface, and then the 3D geometric contour of the defect is reconstructed.

[0092] Intelligent Defect Recognition and Assessment: By integrating the amplitude and waveform features of ultrasonic echoes with the texture and shape features of three-dimensional magnetic flux leakage images, and inputting them into a convolutional neural network classifier, intelligent identification and quantitative assessment of defect types are completed, and the location, type, size, and severity of defects are output.

[0093] Inspection report generation: Integrate all inspection data to generate a comprehensive inspection report including metal cross-sectional area loss curve, three-dimensional magnetic flux leakage image, three-dimensional contour map of defects, ultrasonic calibration coordinates and defect assessment results, and complete the online inspection of 8 defects in steel wire rope.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A dual-magnetic-loop decoupling and three-dimensional magnetic reconstructing online detection system for steel wire ropes, characterized in that, include: The system comprises a dual magnetic circuit magnetization unit, a three-dimensional magnetic sensing scanning unit, an ultrasonic triggering and positioning unit, and a signal processing unit that is sequentially and coaxially arranged along the axial direction of the wire rope; The dual magnetic circuit magnetization unit is used to apply a physically decoupled composite magnetic field to the wire rope, and outputs a saturation magnetization field adapted to metal cross-sectional area loss detection and a high gradient leakage magnetic field adapted to local defect detection, respectively. The three-dimensional magnetic sensing scanning unit is used to synchronously acquire the three-dimensional spatial vector data of the defect leakage magnetic field generated by the high-gradient leakage magnetic field excitation; The ultrasonic triggering and positioning unit is used to receive the trigger signal from the signal processing unit, emit and receive ultrasonic guided waves based on the magnetostrictive effect, and obtain the axial coordinates of the defect. The signal processing unit is used to receive the three-dimensional spatial vector data and axial coordinates, complete the reconstruction of the three-dimensional magnetic flux leakage image of the defect, the calibration of the axial coordinates and the inversion of the three-dimensional geometric contour, and output the detection results.

2. The online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction according to claim 1, characterized in that, The dual magnetic circuit magnetization unit includes an outer magnetic circuit, an inner magnetic circuit, and a magnetic isolation layer located between the outer magnetic circuit and the inner magnetic circuit, all coaxially nested. The external magnetic circuit is used to magnetize the wire rope to saturation, and the relationship between the total magnetic flux and the cross-sectional area of ​​the wire rope is established based on Ohm's law of magnetic circuits. The internal magnetic circuit is used to establish a high-gradient local magnetic field on the surface of the wire rope, and to excite local defects to generate a leakage magnetic field based on the magnetic dipole model. The magnetic isolation layer is used to decouple the physical signal sources of the outer magnetic circuit and the inner magnetic circuit.

3. The online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic reconstruction according to claim 2, characterized in that, The outer magnetic circuit includes a first permanent magnet and a first yoke, and the magnetic path of the outer magnetic circuit passes through the cross-section of the wire rope. The inner magnetic circuit includes a second permanent magnet, a second yoke, and a magnetic armature, and the inner magnetic circuit is distributed on the surface of the wire rope.

4. The online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction according to claim 1, characterized in that, The three-dimensional magnetic sensing scanning unit includes an array of multiple triaxial magnetic sensors, a data acquisition subunit, and a circumferential scanning drive mechanism. The triaxial magnetic sensor integrates three orthogonal sensing axes to simultaneously measure the axial, normal, and circumferential components of the leakage magnetic field. The array is uniformly arranged along the circumference of the wire rope for high-resolution sampling of the circumferential morphology of the defect. The acquisition subunit is used to synchronously acquire the three-component magnetic field data of all sensors, and the sampling frequency is matched with the speed of the wire rope movement.

5. The online detection system for steel wire rope with dual magnetic circuit decoupling and three-dimensional magnetic induction reconstruction according to claim 1, characterized in that, The ultrasonic triggering and positioning unit includes an ultrasonic probe, a pulse excitation subunit, and an echo processing subunit. The pulse excitation subunit is used to output a high-frequency pulse current to the ultrasonic probe when the signal processing unit detects that the local defect signal exceeds a preset threshold. The echo processing subunit is used to receive the ultrasonic echo reflected from the defect, measure the time difference between the transmitted pulse and the echo, and calculate the precise axial position of the defect based on the principle of pulse reflection.

6. The online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction according to claim 1, characterized in that, The signal processing unit is configured to perform a three-dimensional magnetic flux leakage image reconstruction operation: The collected three-dimensional magnetic field data is organized into a three-dimensional data volume, in which the axial position is determined by the speed and time of the steel wire rope movement, and the circumferential position is determined by the sensor array layout. The magnetic field strength is converted into color values ​​by pseudo-color mapping, and three two-dimensional pseudo-color images of axial component, normal component and circumferential component are generated respectively. Among them, the axial component image reflects the axial polarity change of the defect, the normal component image reflects the depth and opening characteristics of the defect, and the circumferential component image reflects the circumferential extension range and twisting of the defect.

7. The online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction according to claim 1, characterized in that, The signal processing unit solves the three-dimensional geometric contour of the defect based on the magnetic charge model and the finite element inverse problem. Its objective function includes error terms between the measured magnetic field and the forward calculated magnetic field, as well as regularization terms to ensure the smoothness of the solution. By minimizing the objective function using the conjugate gradient method, the magnetic charge distribution on the defect surface is obtained, and the three-dimensional geometric contour of the defect is reconstructed.

8. The online detection system for steel wire rope with dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction according to claim 1, characterized in that, The signal processing unit is further configured to: The precise axial coordinates obtained by ultrasonic positioning are used to perform axial calibration on the three-dimensional magnetic flux leakage image, eliminating the cumulative positioning error caused by encoder slippage and wire rope creep. By integrating the amplitude and waveform characteristics of ultrasonic echoes with the characteristics of three-dimensional magnetic flux leakage images, and inputting them into a convolutional neural network classifier, intelligent identification and quantitative assessment of defect types can be achieved.

9. A method for online detection of steel wire ropes using dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction, characterized in that, The online detection system for steel wire rope based on the dual magnetic loop decoupling and three-dimensional magnetic induction reconstruction according to any one of claims 1 to 8 includes: In response to the activation trigger of online wire rope detection, a physically decoupled composite magnetic field is applied to the moving wire rope by a dual magnetic loop magnetization unit arranged coaxially along the wire rope axis, which respectively generates a saturation magnetization field suitable for metal cross-sectional area loss detection and a high gradient leakage magnetic field suitable for local defect detection. The magnetic flux change data of the external magnetic circuit is collected by a metal cross-sectional area loss detection sensor, and the three-dimensional spatial vector data of the defect leakage magnetic field is collected simultaneously by a triaxial magnetic sensor array. The collected data is preprocessed to obtain a complete detection dataset. The magnetic field signal in the detection data is monitored in real time. After identifying the abnormal signal of local defects, the ultrasonic triggering and positioning unit is controlled to transmit and receive ultrasonic guided waves based on the magnetostrictive effect. The precise axial coordinate of the defect is calculated by using the pulse reflection method. Three-dimensional magnetic flux leakage images are reconstructed based on three-dimensional spatial vector data, and image axial calibration is completed using ultrasonic positioning coordinates; Solve the inverse finite element problem based on the magnetic charge model to reconstruct the three-dimensional geometric contour of the defect; By integrating ultrasonic echo amplitude, waveform characteristics, and three-dimensional magnetic flux leakage image characteristics, intelligent identification of defect types can be achieved; By integrating all the test data, a comprehensive test report is generated, which includes the metal cross-sectional area loss curve, three-dimensional magnetic flux leakage image, three-dimensional contour map of the defect, and ultrasonic calibration coordinates, thus completing the online detection of wire rope defects.

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