Miniaturized steel cable magnetic flux leakage flaw detection equipment

Abstract

The utility model relates to miniaturized steel cable magnetic flux leakage flaw detection equipment, which belongs to the technical field of steel cable nondestructive testing and comprises a magnetic shielding shell, a magnetizing device, a detecting device, an ultrasonic module and a control circuit. The magnetizing device adopts a Halbach permanent magnet array to construct a closed magnetic circuit. The detection device comprises a Hall sensor array which is arranged in a double-ring differential mode. And the magnetic shielding shell is enclosed to form a closed detection chamber to isolate interference. Through the structural design, high integration and miniaturization of flaw detection equipment are realized, the precision and reliability of detecting a small-diameter steel cable in a complex electromagnetic environment and a narrow space are remarkably improved, and meanwhile, good portability and environmental adaptability are achieved.

Description

Technical Field

[0001] This utility model relates to the field of nondestructive testing technology for steel cables, specifically a miniaturized magnetic flux leakage testing device for steel cables. Background Technology

[0002] Steel cables, as critical load-bearing components, are widely used in bridges, elevators, aircraft, and various lifting machinery. Defects such as broken wires, corrosion, and wear that appear inside or on the surface can directly threaten the safety of the overall structure. Currently, non-destructive testing of steel cables mainly relies on manual inspection or traditional flaw detection equipment. Manual inspection is inefficient, highly subjective, and difficult to detect internal defects; while existing flaw detection equipment such as magnetic particle and ultrasonic testing equipment is often bulky, complex to operate, and has high requirements for the testing environment, making it particularly difficult to adapt to confined spaces or field operations. Furthermore, when performing high-precision quantitative testing on thin-diameter steel cables, it often faces problems of insufficient sensitivity and weak anti-interference capabilities.

[0003] Specifically, the technical challenges are even more pronounced when it comes to precision flaw detection of thin-diameter steel cables (e.g., 2-6 mm in diameter). Conventional magnetic flux leakage (MF) testing equipment, due to limitations in its magnetic circuit design, struggles to achieve uniform and sufficient saturation magnetization of thin cables within a confined space, resulting in weak MF signals and low signal-to-noise ratios. Furthermore, existing equipment has limitations in sensor integration, suppression of external electromagnetic interference, and intelligent identification of multiple defect modes, often failing to simultaneously achieve optimal detection accuracy, equipment portability, and environmental adaptability. Particularly noteworthy is the inherent limitation of single-mode detection: MF testing is sensitive to volumetric defects but has limited ability to identify surface microcracks; traditional eddy current testing, while sensitive to surface and near-surface defects, is susceptible to the "skin effect" and suffers from low signal-to-noise ratios; and ultrasonic testing is effective for internal defects but struggles to identify fine surface damage.

[0004] Therefore, the industry urgently needs a miniaturized steel cable flaw detection device that integrates multimodal sensing, has a compact structure, provides accurate detection, and is suitable for complex field environments. Utility Model Content

[0005] To address the problems of existing technologies, this invention provides a miniaturized magnetic flux leakage testing device for steel cables.

[0006] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution: a miniaturized steel cable magnetic leakage flaw detection device, a magnetic shielding shell, the magnetic shielding shell enclosing a closed detection chamber for isolating external magnetic field interference;

[0007] A magnetization device, installed inside the detection chamber, includes a magnetic yoke and a highly permanent magnet, used to saturate magnetize the steel cable passing through the detection chamber;

[0008] The detection device includes multiple Hall sensors arranged in an array within the detection chamber to collect the leakage magnetic signal of the steel cable.

[0009] An integrated ultrasonic wave generator and receiver module is installed inside the detection chamber to transmit ultrasonic waves to the steel cable and receive echo signals.

[0010] The signal amplification module, located inside the detection chamber and electrically connected to the Hall sensor, is used to pre-amplify the leakage magnetic signal;

[0011] And control circuitry, integrated inside the detection chamber, for coordinating the timing control of the magnetization device, detection device, and signal processing unit.

[0012] In one specific embodiment, the magnetic shielding shell includes a first magnetic shield, a second magnetic shield, a third magnetic shield, and a fourth magnetic shield, forming a magnetic shielding structure to enhance magnetic field stability.

[0013] In one specific implementation, the magnetization device uses a Halbach permanent magnet array to construct a closed magnetic circuit, and the magnetic pole spacing is modularly adjustable according to the steel cable diameter of 2-6mm; the permanent magnet is made of N52 grade neodymium iron boron material, with a magnetization intensity ≥1.8T.

[0014] In one specific embodiment, the detection device contains eight Hall sensors, which are evenly distributed around the steel cable in a 2x4 matrix, with a lift-off distance of 2mm; the Hall sensors are AH3505 linear integrated Hall elements with a sensitivity of 25.0mV / mT.

[0015] In one specific implementation, the Hall sensor adopts a dual-ring differential arrangement, including two detection rings, ring A and ring B, with an axial distance of 20mm between the two rings. The magnetic field sensing directions of the Hall elements at corresponding positions within the rings are set to be opposite, which is used to eliminate external interference through differential processing.

[0016] There are three signal amplification modules, arranged in parallel along the axis of the steel cable to form a row. Two rows of Hall sensors are located inside the three signal amplification modules and are distributed at intervals.

[0017] In one specific embodiment, an internal support body is provided inside the magnetic shielding shell. The internal support body includes a first support body and a second support body, which are used to fix the magnetic yoke, the high-permanent magnet, the ultrasonic wave generator and receiver integrated module, the signal amplification module and the Hall sensor to ensure structural stability.

[0018] In one specific embodiment, the magnetic yoke is fixedly disposed between the second magnetic shield and the first support, and two high permanent magnets are provided. The two high permanent magnets are fixedly disposed in two grooves on one side of the first support. An installation groove is provided between the first support and the second support for placing and installing the ultrasonic wave generator and receiver integrated module, the signal amplification module and the Hall sensor.

[0019] In one specific implementation, the signal amplification module integrates a zero-adjustment circuit to eliminate the static output voltage of the Hall element; the zero-adjustment circuit adopts a differential amplification structure and achieves zero adjustment by adjusting the reference voltage through a potentiometer.

[0020] In one specific implementation, the control circuit uses an FPGA chip to achieve synchronous acquisition of multi-channel signals, with the sampling rate configured as follows: 1MHz for leakage magnetic signal, 500kHz for eddy current signal, and 2MHz for ultrasonic signal, to ensure timing accuracy.

[0021] In one specific embodiment, an eddy current detection coil is also included, which is integrated into the detection chamber and is used to generate a high-frequency alternating magnetic field and detect eddy current field disturbance signals caused by surface and near-surface defects of the steel cable.

[0022] In one specific implementation, the probe of the device has external dimensions of 130mm long × 60mm wide × 47mm high, and a total weight of ≤1kg; the weight of the entire device, including the storage box and the operating plate, is ≤4kg, making it suitable for detection in confined spaces.

[0023] The equipment operates in a temperature range of -20℃ to +40℃, with a relative humidity of ≤90%RH in the storage environment. It also features a modular clamping device that supports the rapid replacement and adaptation of steel cables ranging from Φ2 to 6mm.

[0024] A steel cable transmission mechanism can also be fixed to one end of the magnetic shielding shell to transmit the steel cable at a constant speed.

[0025] The beneficial effects of this utility model are as follows:

[0026] 1. This invention improves the detection accuracy and reliability of defects in thin-diameter steel cables through magnetic circuit and sensing structure design. By employing a magnetization device based on a Halbach permanent magnet array and a closed magnetic circuit composed of a multi-layered magnetic shielding shell, the device achieves probe miniaturization while generating a stable and highly concentrated saturated magnetic field, providing excellent resistance to external interference in the detection environment. Furthermore, by using a Hall sensor array with a dual-ring differential arrangement and a signal amplification module integrating a zero-adjustment circuit, the system can highly sensitively capture weak leakage magnetic signals caused by defects and effectively suppress environmental noise and common-mode interference. The synergistic effect of these structural features enables the device to overcome the limitations of traditional methods in detecting thin-diameter steel cables, achieving high-precision identification and accurate positioning of minute defects.

[0027] 2. The highly integrated and modular physical structure significantly enhances the applicability, portability, and environmental robustness of the equipment. This invention precisely integrates a multimodal sensor and signal processing circuitry into a compact magnetically shielded housing via an internal support, achieving extreme lightweighting and structural robustness of the probe. The magnetic pole spacing of the magnetization device is modularly adjustable, and with a quick-change clamping adapter, a single device can flexibly adapt to the inspection needs of steel cables of different diameters. Furthermore, rigorous structural and material design ensures the stability of the equipment in a wide temperature range and harsh humidity environments. This design enables the equipment to be widely used in complex sites and confined spaces such as bridges, cableways, and aircraft, solving the problem that traditional large equipment cannot easily enter specific scenarios for inspection. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0029] Figure 2 This is a schematic diagram of the internal structure of the magnetic shielding shell of this utility model.

[0030] Figure 3 This is a schematic diagram of the internal support structure connection of this utility model.

[0031] Figure 4 This is a schematic diagram of the signal amplification module and Hall sensor structure of this utility model.

[0032] Figure 5 This is a schematic diagram of the installation of the ultrasonic wave generator and receiver integrated module of this utility model.

[0033] Figure 6 This is a schematic diagram of the installation of the steel cable transmission mechanism of this utility model.

[0034] Figure 7 This is a schematic diagram of the magnetic field distribution of the ring array of this utility model.

[0035] Figure 8 This is a schematic diagram of the arrangement of the dual-ring differential Hall sensor of this utility model.

[0036] Figures 1 to 8 In the middle: 1. Magnetic shielding shell; 11. First magnetic shield; 12. Second magnetic shield; 13. Third magnetic shield; 14. Fourth magnetic shield; 2. Magnetic yoke; 3. Internal support; 31. First support; 32. Second support; 4. High-strength permanent magnet; 5. Integrated ultrasonic generator and receiver module; 6. Signal amplification module; 7. Hall sensor; 8. Steel cable; 9. Steel cable transmission mechanism. Detailed Implementation

[0037] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0038] like Figures 1 to 8 The image shows a miniaturized magnetic flux leakage testing device for steel cables.

[0039] The first part describes the magnetization device of this equipment, which employs a closed magnetic circuit constructed based on a Halbach permanent magnet array. For example... Figure 7 As shown, this array, by arranging permanent magnets with different magnetization directions in a specific sequence, can concentrate magnetic field lines on the side facing the steel cable, making the magnetic field strength about 1.4 times that of traditional arrangements, while weakening the magnetic field on the other side to reduce stray interference. Combined with N52 grade neodymium iron boron material (magnetization ≥1.8T) and an industrial pure iron yoke, a magnetic circuit with low magnetic resistance and high magnetic flux density is formed, ensuring effective saturation magnetization of thin steel cables with a diameter of 2-6mm.

[0040] The overall structure of the equipment mainly includes the following parts:

[0041] The magnetic shielding housing 1 is formed by a first magnetic shield 11, a second magnetic shield 12, a third magnetic shield 13 and a fourth magnetic shield 14 to create a closed detection chamber, which is used to effectively isolate external magnetic field interference and ensure the stability of the internal detection signal.

[0042] The magnetization device, located within the detection chamber, includes a magnetic yoke 2 and two high-strength permanent magnets 4. The high-strength permanent magnets 4 are made of N52 grade neodymium iron boron material with a magnetization intensity ≥1.8T. A closed magnetic circuit is constructed through a Halbach permanent magnet array, and the pole spacing can be modularly adjusted according to the diameter of the steel cable (2-6mm) to achieve saturation magnetization of the steel cable 8.

[0043] The detection device includes eight AH3505 linear integrated Hall sensors 7, evenly distributed around the steel cable in a 2x4 matrix, with a lift distance of 2mm. The sensors adopt a dual-ring differential arrangement, consisting of ring A and ring B, with an axial distance of 20mm between the two rings. The magnetic field sensing directions of the sensors within each ring are set to opposite directions to eliminate external interference through differential processing.

[0044] The Hall sensor employs a dual-ring differential layout, such as... Figure 8As shown, the axial distance between rings A and B is 20mm, and the magnetic field sensing directions of the Hall elements at corresponding positions within the rings are set to opposite directions. When the steel cable passes through, common-mode signals such as environmental electromagnetic interference and vibration noise behave consistently in both rings, while the leakage magnetic field signal caused by defects exhibits spatial locality and manifests as a differential-mode signal. Subtracting the signals from the two rings using a subsequent differential amplifier circuit can effectively suppress common-mode interference and significantly improve the signal-to-noise ratio and defect detection sensitivity.

[0045] The ultrasonic wave generator and receiver module 5 is installed in the detection chamber and is used to emit ultrasonic waves to the steel cable and receive echo signals to achieve auxiliary detection of internal defects in the steel cable.

[0046] Signal amplification modules 6, consisting of three units arranged side-by-side along the cable axis, each integrate a zero-adjustment circuit and employs a differential amplification structure. The reference voltage is adjusted via a potentiometer to eliminate the static output voltage of the Hall element. For eddy current signals, the equipment also includes a dual-channel bandpass filter with center frequencies set to 100kHz and 1MHz (bandwidth ±5%), used to separate the dual-frequency excitation signals and suppress out-of-band noise.

[0047] The control circuit, integrated inside the detection chamber, uses an FPGA chip to achieve synchronous acquisition and timing control of multi-channel signals, supporting synchronous processing of three signals: magnetic flux leakage, eddy current, and ultrasound. The core of the control circuit is the FPGA chip, configured to output a unified hardware trigger signal with nanosecond-level clock jitter to the magnetic flux leakage, eddy current, and ultrasound sensors, achieving strict synchronous acquisition of multi-channel signals. Specifically, the magnetic flux leakage signal is converted to a 16-bit digital signal at a 1MHz sampling rate, the eddy current signal is input at a 500kHz sampling rate, and the ultrasound signal undergoes analog-to-digital conversion at a 2MHz sampling rate. This FPGA-based hardware synchronization mechanism ensures precise alignment of multi-modal signals in the time domain, providing a foundation for subsequent signal fusion.

[0048] The internal support 3, including the first support 31 and the second support 32, is used to fix the magnetic yoke, the high permanent magnet, the ultrasonic module, the signal amplification module and the Hall sensor, to ensure the stability of the overall structure.

[0049] The cable drive mechanism 9 can be optionally installed at one end of the magnetic shielding shell to drive the cable through the detection chamber at a constant speed, thereby achieving continuous detection.

[0050] Part Two: Workflow and Principles

[0051] This equipment integrates sensors with three detection modes: magnetic flux leakage, eddy current, and ultrasonic, achieving full-coverage detection of defects in steel cables. The magnetic flux leakage sensor is sensitive to internal volume defects, the eddy current coil excels at capturing surface and near-surface cracks, and the ultrasonic module can perform contour imaging of internal defects. Signals from each sensor are synchronously acquired by an FPGA, then amplified and filtered by a signal conditioning circuit. Finally, the built-in processing unit performs feature extraction and fusion analysis, enabling high-precision identification and location of various defects such as broken wires, corrosion, and wear.

[0052] (a) Complete workflow.

[0053] The workflow of this device is a closed-loop process from physical signal acquisition to intelligent analysis and decision-making, which can be divided into the following sequential steps:

[0054] Step 1: Equipment preparation and steel cable installation.

[0055] Power-on self-test: When the device is powered on, the FPGA control circuit starts and performs a self-test on each sensor module (Hall sensor, ultrasonic module) and signal chain to confirm that the working status is normal.

[0056] Installation and Adaptation: Select the appropriate modular clamping adapter according to the diameter of the steel cable to be tested (Φ2-6mm). Pass the steel cable through the detection chamber in the center of the magnetic shielding housing 1, and prepare it by means of a transmission mechanism (if installed) or manual traction.

[0057] Parameter settings: Select or input parameters such as cable specifications (e.g., diameter 2.5mm, 7×7 structure) and preset detection speed (0.5-3m / s) through the human-machine interface (e.g., operating tablet).

[0058] Step 2: Synchronous acquisition of saturation magnetization and multi-mode signals.

[0059] Magnetization Initiation: The control circuit drives the magnetization device to operate. The Halbach permanent magnet array generates a high-intensity (≥1.8T), highly uniform static magnetic field, which saturates the cross-section of the steel cable passing through the chamber. The magnetic yoke 2 and the magnetic shielding shell 1 together form a low-resistivity closed magnetic circuit, efficiently concentrating the magnetic field on the steel cable.

[0060] Triggering and Synchronization Acquisition: The steel cable begins to move at a constant speed (or the equipment moves along the steel cable). The FPGA sends a unified synchronization trigger signal (clock jitter <1ns) to coordinate the simultaneous start-up of the three detection channels:

[0061] Magnetic leakage flux (MFL) channel: Abrupt changes in magnetic permeability at defects in the steel cable (such as broken wires) cause magnetic field distortion, generating a "leakage magnetic field". An array of eight dual-ring differential Hall sensors 7, arranged around the steel cable and raised 2mm away, converts the radial component of the leakage magnetic field into a weak voltage signal. The signal is immediately pre-amplified and zeroed by the adjacent signal amplification module 6 to eliminate static voltage offset.

[0062] Eddy Current (EC) Channel: An eddy current detection coil integrated within the cavity is excited to generate a high-frequency alternating magnetic field. Defects on or near the surface of the steel cable disturb the eddy current field, causing changes in the coil impedance. This signal is extracted by a lock-in amplifier.

[0063] Ultrasonic (PAUT) Channel: The integrated ultrasonic generator and receiver module 5 transmits ultrasonic pulses to the steel cable. The sound waves propagate inside the steel cable and are reflected when they encounter defects (such as internal cracks or corrosion) or boundaries. The receiver captures the echo signals.

[0064] Signal digitization: Three analog signals are synchronously converted into digital signals by a high-speed ADC.

[0065] The amplified and conditioned leakage magnetic signal is digitized at a sampling rate of 1MHz and a resolution of 16 bits.

[0066] The eddy current impedance signal is digitized at a sampling rate of 500kHz after bandpass filtering.

[0067] The ultrasonic echo signal, after being amplified and compensated by variable gain, is digitized at a sampling rate of 2MHz.

[0068] Step 3: Signal preprocessing and feature extraction.

[0069] FPGA or dedicated signal processing circuits perform real-time preprocessing and feature extraction on synchronously acquired digital signals:

[0070] The leakage magnetic field signal is denoised and shaped to suppress environmental electromagnetic interference and inherent strand wave signals of the steel cable, and to correct baseline drift caused by speed fluctuations.

[0071] Frequency domain analysis was performed on the eddy current signal to separate and extract the frequency components that reflect the defect characteristics.

[0072] Envelope extraction and peak localization of ultrasonic echo signals are performed to determine echo arrival time and amplitude information.

[0073] Subsequently, the processing circuit automatically extracts a set of feature quantities (such as the gradient features of leakage magnetic signals, the frequency domain features of eddy current signals, and the wave velocity and attenuation features of ultrasonic signals) from the preprocessed modal signals, and constructs them into a multi-dimensional feature vector for subsequent fusion judgment.

[0074] Step 4: Multimodal feature fusion and intelligent recognition.

[0075] The device's built-in data processing and fusion unit receives feature vectors from various sensors. This unit dynamically and comprehensively evaluates defect information from leakage flux, eddy currents, and ultrasonic modes based on the quality of each channel's signal (e.g., signal-to-noise ratio, signal strength). The fused features are then fed into a pre-set defect classification and recognition module. This module, based on judgment rules generated from a large number of samples, performs high-speed calculations and matching on the input features, ultimately outputting the defect type (e.g., broken wire, corrosion, wear), location coordinates, and severity level. Experiments show that the device achieves high average recognition accuracy and low positioning error for the aforementioned defects.

[0076] Step 5: Results output, storage, and decision support.

[0077] Real-time display: The identification results (defect type, location, severity level) are displayed graphically on the operating tablet in real time, allowing you to intuitively see the "health map" of the steel cable.

[0078] Data storage: The complete original waveform, processed feature data, diagnostic results, cable ID, detection time and other information are stored locally on the device or uploaded to the cloud database. The data storage capacity for a single detection is greater than 10,000 meters of cable length.

[0079] Report Generation and Early Warning: Automatically generates structured inspection reports. The system supports comparative analysis with historical inspection data to predict trends and issues early warnings when critical defects or accelerated damage are detected, driving a shift in maintenance strategies from "passive repair" to "proactive prevention."

[0080] (II) In-depth explanation of working principle.

[0081] The effectiveness of this equipment is based on the synergy of the following core principles:

[0082] Based on the saturation magnetization principle of Halbach array.

[0083] Objective: To create the necessary conditions for magnetic flux leakage detection. Only when the ferromagnetic steel cable is magnetized to near saturation (above the knee of the magnetization curve) will the magnetic field lines be forced to overflow into the air in large quantities when a defect occurs, forming a strong, detectable magnetic flux leakage field.

[0084] Implementation: A Halbach permanent magnet array is employed. This structure, by arranging permanent magnet blocks with different magnetization directions in a specific sequence, can concentrate magnetic field lines on one side (facing the steel cable), achieving a magnetic field strength approximately 1.4 times that of conventional arrangements; while weakening the magnetic field on the other side to reduce stray interference. Combined with high-energy-product N52 neodymium iron boron magnets and industrial pure iron yokes, a closed magnetic circuit with extremely low magnetic reluctance and a highly concentrated and uniform magnetic field is formed, ensuring effective saturation magnetization of Φ2-6mm thin-diameter steel cables.

[0085] Magnetic flux leakage (MFL) detection and dual-ring differential sensing principle.

[0086] Physics Basis: Faraday's law of electromagnetic induction and the principle of magnetic field continuity. Under saturation magnetization, the magnetic flux density inside the steel cable is uniform. When defects such as broken wires or corrosion exist, the permeability at that location is much lower than that of intact metal, and the magnetic reluctance increases sharply, causing some magnetic lines of force to be "squeezed out" from the surface of the steel cable, forming a spatially distributed leakage magnetic field.

[0087] Signal acquisition: The radial component (Br) of the leakage magnetic field is directly measured using a linear Hall element (AH3505). Its output voltage... It is proportional to the magnetic field strength B and independent of the speed of the steel cable, making it suitable for dynamic detection.

[0088] Anti-interference design: A "dual-ring differential arrangement" is adopted. The A and B ring sensors are axially spaced 20mm apart and have opposite sensing directions. They are simultaneously subjected to the same common-mode signals such as environmental electromagnetic interference and vibration noise, while the leakage magnetic signal generated by defects is spatially localized and manifests as a differential-mode signal on the two rings. Subtracting the signals from the two rings can greatly suppress common-mode interference and significantly improve the signal-to-noise ratio.

[0089] The complementary principle of multimodal sensing.

[0090] Eddy current testing (EC): Based on the "skin effect" in electromagnetic induction. The magnetic field generated by the high-frequency excitation coil induces eddy currents on the surface of the steel cable. This eddy current field is extremely sensitive to surface and near-surface defects (such as fine cracks and shallow corrosion) and has a fast response speed. Its impedance change provides information on the conductivity and magnetic permeability of the defects, complementing magnetic flux leakage detection (sensitive to volume defects).

[0091] PAUT (Propagation and Attenuation Ultrasonic Testing): Based on the propagation, reflection, and attenuation characteristics of sound waves in elastic media. Ultrasonic waves can penetrate the interior of steel cables, offering unique advantages in detecting internal defects (such as core fractures) and changes in cross-sectional area caused by corrosion. By measuring echo time, amplitude, and waveform, information on the depth, orientation, and size of defects can be obtained.

[0092] Synergistic effect: MFL excels at detecting macroscopic volumetric losses, EC excels at capturing surface micro-injuries, and PAUT excels at probing internal structures. The combination of the three achieves comprehensive coverage from surface to interior, from macro to micro, overcoming the blind spots of single technologies.

[0093] The intelligent diagnostic principle is based on the fusion of FPGA and feature level.

[0094] Hardware Core (FPGA): The Field Programmable Gate Array provides ultimate timing control precision and parallel processing capabilities. It can achieve nanosecond-level synchronous acquisition of three signals and simultaneously run preprocessing algorithms (filtering, transformation, detection) to meet the requirements of high-speed, real-time detection.

[0095] High-performance synchronous processing principle based on FPGA.

[0096] The core hardware of this device lies in its synchronous control and processing architecture built using FPGA chips. The FPGA provides nanosecond-level precision hardware triggering, ensuring strictly synchronous acquisition of multimodal signals. Its parallel processing capabilities enable real-time preprocessing (such as filtering and transformation) of three high-speed data streams, providing the hardware foundation for subsequent real-time analysis.

[0097] Multimodal information collaboration and intelligent diagnosis principles.

[0098] The device integrates a multi-channel data fusion processing circuit to collaboratively process information from three sensors: magnetic flux leakage, eddy current, and ultrasonic sensors. This circuit does not simply superimpose signals; instead, it uses built-in logic to weight and comprehensively evaluate them, thus overcoming the detection blind spots of single technologies. Finally, the embedded intelligent recognition unit performs rapid matching and decision-making based on a pre-stored large defect pattern library, achieving high-precision and high-reliability identification and evaluation of complex defects.

[0099] In summary, this equipment achieves high-quality signal acquisition through precise magnetic circuit and sensor structure design, expands the detection range through the physical complementarity of multimodal sensing, and finally achieves high-precision and high-reliability defect identification and assessment through FPGA-based synchronous acquisition and intelligent fusion algorithms, forming a complete, efficient, and intelligent miniaturized steel cable flaw detection technology solution.

[0100] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A miniaturized magnetic flux leakage testing device for steel cables, characterized in that: A magnetic shielding shell (1) is formed to enclose a closed detection chamber for isolating external magnetic field interference; A magnetization device, disposed within the detection chamber, includes a yoke (2) and a highly permanent magnet (4) for saturating magnetization of a steel cable (8) passing through the detection chamber; The detection device includes multiple Hall sensors (7) arranged in an array in the detection chamber for collecting the leakage magnetic signal of the steel cable; An integrated ultrasonic wave generator and receiver module (5) is installed in the detection chamber and is used to transmit ultrasonic waves to the steel cable and receive echo signals. The signal amplification module (6) is disposed in the detection chamber and electrically connected to the Hall sensor (7) for pre-amplifying the leakage magnetic signal; And a control circuit, integrated inside the detection chamber, for coordinating the timing control of the magnetization device, the detection device and the signal processing unit.

2. The miniaturized magnetic flux leakage testing equipment for steel cables according to claim 1, characterized in that: The magnetic shielding shell (1) includes a first magnetic shield (11), a second magnetic shield (12), a third magnetic shield (13) and a fourth magnetic shield (14), forming a magnetic shielding structure to enhance magnetic field stability.

3. The miniaturized magnetic flux leakage testing equipment for steel cables according to claim 1, characterized in that: The magnetization device uses a Halbach permanent magnet array to construct a closed magnetic circuit, and the magnetic pole spacing is modularly adjustable according to the steel cable diameter of 2-6mm; the high permanent magnet (4) is N52 grade neodymium iron boron material with a magnetization intensity ≥1.8T.

4. The miniaturized magnetic flux leakage testing equipment for steel cables according to claim 1, characterized in that: In the detection device, there are eight Hall sensors (7), which are evenly distributed around the steel cable in a matrix of 2 rows and 4 columns, with a lifting distance of 2 mm; the Hall sensor (7) is an AH3505 linear integrated Hall element with a sensitivity of 25.0 mV / mT.

5. A miniaturized magnetic flux leakage testing device for steel cables according to claim 4, characterized in that: The Hall sensor (7) adopts a double-ring differential arrangement, including two detection rings, A ring and B ring, with an axial distance of 20mm between the two rings. The magnetic field sensitive directions of the Hall elements at corresponding positions within the rings are set to be opposite, which is used to eliminate external interference through differential processing. The signal amplification module (6) is provided in three rows, arranged in parallel along the axis of the steel cable to form a row. The two rows of Hall sensors (7) are located inside the three signal amplification modules (6) and are distributed at intervals.

6. The miniaturized magnetic flux leakage testing equipment for steel cables according to claim 1, characterized in that: The magnetic shielding shell (1) is provided with an internal support (3), which includes a first support (31) and a second support (32) for fixing the magnetic yoke (2), the high permanent magnet (4), the ultrasonic wave generator and receiver integrated module (5), the signal amplification module (6) and the Hall sensor (7) to ensure structural stability.

7. A miniaturized magnetic flux leakage testing device for steel cables according to claim 6, characterized in that: The magnetic yoke (2) is fixedly disposed between the second magnetic shield (12) and the first support (31). Two high permanent magnets (4) are provided. The two high permanent magnets (4) are fixedly disposed in two grooves on one side of the first support (31). An installation groove is provided between the first support (31) and the second support (32) for placing and installing the ultrasonic wave generator and receiver integrated module (5), the signal amplification module (6) and the Hall sensor (7).

8. The miniaturized magnetic flux leakage testing equipment for steel cables according to claim 1, characterized in that: The signal amplification module (6) integrates a zero-adjustment circuit to eliminate the static output voltage of the Hall element; the zero-adjustment circuit adopts a differential amplification structure and achieves zero adjustment by adjusting the reference voltage through a potentiometer.

9. A miniaturized magnetic flux leakage testing device for steel cables according to claim 1, characterized in that: It also includes an eddy current detection coil, which is integrated into the detection chamber and is used to generate a high-frequency alternating magnetic field and detect eddy current field disturbance signals caused by surface and near-surface defects of the steel cable.

10. A miniaturized magnetic flux leakage testing device for steel cables according to claim 1, characterized in that: The probe of the device has external dimensions of 130mm (length) × 60mm (width) × 47mm (height) and a total weight of ≤1kg; the weight of the entire device, including the storage box and operating plate, is ≤4kg, making it suitable for detection in confined spaces. The equipment operates in a temperature range of -20℃ to +40℃, with a relative humidity of ≤90%RH in the storage environment. It also employs a modular clamping device to support the rapid replacement and adaptation of Φ2-6mm steel cables.

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