Steel structure detection device based on magnetostrictive guided waves and working method

Abstract

The invention belongs to the technical field of steel structure monitoring, and particularly relates to a steel structure detection device based on magnetostrictive guided waves and a working method.The device comprises a vehicle body frame, a moving and obstacle crossing mechanism is arranged on the vehicle body frame, and the moving and obstacle crossing mechanism enables the device to be attracted to the surface of a steel structure through an electromagnet; the magnetostrictive guided wave detection system comprises a probe assembly and a probe execution mechanism for driving the probe assembly to press or separate from the surface of the steel structure; the probe assembly comprises at least two permanent magnets which are arranged in parallel and have opposite magnetic poles, an exciting and receiving coil is arranged between the two permanent magnets, and a dry coupling pad is arranged at the bottom of the permanent magnet close to the surface of the steel structure; the integrated control system is configured to control the movement of the device, and / or to control the excitation and receiving coil to generate guided waves and receive return signals, and / or to synchronize positional information. The problems that in an existing device, coupling between a probe and the surface of a steel structure is unstable, and the platform adsorption and obstacle crossing capacity is insufficient are solved.

Description

Technical Field

[0001] This invention belongs to the field of steel structure monitoring technology, specifically a steel structure detection device and its working method based on magnetostrictive guided waves. Background Technology

[0002] The statements in this section only refer to the background technology related to this invention and do not necessarily constitute prior art.

[0003] Fatigue crack detection in large steel structures (such as bridges and factories) is crucial for ensuring their safe service. Currently, existing technologies are gradually adopting wall-climbing robots equipped with non-destructive testing probes for automated on-machine inspection, replacing high-risk manual inspection. However, the probe structures used in these existing automated inspection devices often employ simple spring or pneumatic clamping mechanisms, which cannot maintain constant contact pressure under actual working conditions such as uneven steel surface surfaces and weld protrusions. As the wall-climbing robot operates, the inconsistent contact pressure causes pressure fluctuations, which in turn cause continuous changes in coupling conditions (such as the thickness of the coupling agent layer or the compression of the dry coupling pad), resulting in amplitude drift and phase distortion of the ultrasonic guided wave signal. This not only drowns out the weak reflected signals of tiny defects, leading to missed detections, but also significantly reduces the accuracy of quantitative analysis based on signal amplitude to assess defect size.

[0004] In addition to pressure fluctuations, when the detection surface is locally tilted, uneven, or when the device moves on an inclined wall and generates lateral force, the probe is prone to deflection. This makes it impossible to ensure that the detection surface is uniformly attached to the entire surface of the steel structure, resulting in a reduction in the effective detection area and a decrease in detection performance.

[0005] Some existing technologies attempt to enable wall-climbing robots to overcome obstacles, but after overcoming obstacles, the probes often fail to return to the optimal detection posture, resulting in decreased detection accuracy. Summary of the Invention

[0006] This invention provides a steel structure inspection device and its working method based on magnetostrictive guided waves, which solves the problems of unstable coupling between the probe and the steel structure surface, easy signal distortion, and insufficient adsorption and obstacle-crossing ability of the mobile platform in existing automated wall-climbing inspection devices. This enables safe, efficient, and accurate on-machine automated inspection of large steel structures, replacing high-risk manual inspection.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention discloses a steel structure inspection device based on magnetostrictive guided waves, comprising a vehicle frame, on which: The moving and obstacle-crossing mechanism is used to move the device on the steel structure surface. Both the moving and obstacle-crossing mechanisms are equipped with electromagnets, which cause the device to adhere to the steel structure surface. A magnetostrictive guided wave detection system includes a probe assembly and a probe actuator for driving the probe assembly to achieve continuous scanning detection; the probe assembly includes at least two permanent magnets arranged side by side with opposite magnetic poles, an excitation and receiving coil is provided between the two permanent magnets, and a dry coupling pad is provided at the bottom of the permanent magnet near the surface of the steel structure. An integrated control system is configured to: control the movement of the device, and / or control the excitation and receiving coil to generate guided waves and receive return signals, and / or synchronize position information; The integrated control system includes an airborne main control unit, a navigation and positioning system, and a guided wave excitation acquisition module. The airborne main control unit is electrically connected to the navigation and positioning system, the guided wave excitation acquisition module, the movement and obstacle-crossing mechanism, the electromagnetic adsorption unit, and the probe actuator, respectively. It is used to control the robot to move autonomously along the planned path and synchronously perform continuous scanning detection, and synchronize the continuous detection data with the real-time position information. The integrated control system controls the excitation current of the electromagnetic adsorption unit through pulse width modulation signals to actively adjust the adsorption force. The electromagnetic adsorption unit consists of multiple electromagnets uniformly embedded in the inner layer of the track of the moving and obstacle-crossing mechanism.

[0008] Furthermore, the movement and obstacle-crossing mechanism includes a left-side drive unit and a right-side drive unit with identical structures; each drive unit includes: A side mounting bracket is attached to the side of the vehicle frame, and a drive wheel is provided on the side mounting bracket; The tilting arm has at least two arms, which are arranged in an inverted "V" shape. The top end is hinged to the side mounting base, and the bottom end is hinged to the corresponding driven wheel bracket. The driven wheel bracket is provided with a driven wheel assembly. The driven wheel assembly includes a guide tension wheel located at one end of the driven wheel bracket and a load-bearing wheel at the other end; Tracks, surrounding the guide tension wheel, load-bearing wheel and drive wheel, with electromagnets installed on the inner side of the track or on the track support; The driven wheel bracket is hinged to the bottom end of the tilting arm, so that when the guide tension wheel is subjected to the force of an obstacle perpendicular to the steel surface, it can force the tilting arm to swing outward around its top hinge point through the driven wheel bracket and overcome the preload of the adjustable preload link.

[0009] Furthermore, the drive unit also includes an adjustable preload link, which connects the top ends of the two tilting arms.

[0010] Furthermore, the movement and obstacle-crossing mechanism also includes a through drive shaft that passes through the vehicle frame and is connected to the corresponding drive wheels at both ends. The drive gear is located in the middle of the through drive shaft and meshes with the driven gear. The driven gear is connected to the output shaft of the drive motor. The drive motor drives the through drive shaft and the drive wheels to rotate through the driven gear and the drive gear, thereby driving the tracks.

[0011] Furthermore, the probe actuator includes a lifting drive module. The actuating end of the lifting drive module is connected to the probe assembly via a U-shaped frame. A force sensor is installed between the probe assembly and the U-shaped frame. A detection roller is rotatably connected to the inside of the U-shaped frame. Multiple sets of mounting slots are arranged axially on the outer wall of the detection roller. Multiple probe bodies are arranged in parallel in each mounting slot. The back of each probe body is hinged to one end of an elastic telescopic rod via a hinge. The other end of the elastic telescopic rod is fixedly connected to the bottom of the mounting slot. Driven by the lifting drive module, the probe assembly moves closer to or away from the steel structure surface along the direction of the multiple guide rods, so that the probe body in each mounting slot of each set contacts the steel surface.

[0012] Furthermore, the dry coupling pad is made of abrasion-resistant elastic material.

[0013] Furthermore, the integrated control system includes an airborne main control unit, a navigation and positioning system, and a guided wave excitation acquisition module. The airborne main control unit is electrically connected to the navigation and positioning system, the guided wave excitation acquisition module, the moving and obstacle-crossing mechanism, the electromagnet, and the probe actuator, respectively. It is used to control the movement of the device and to control the excitation and receiving coils to generate guided waves and receive return signals through the guided wave excitation acquisition module. At the same time, it synchronizes the detection data with the position information obtained by the navigation and positioning system.

[0014] Furthermore, the integrated control system controls the excitation current of the electromagnet through pulse width modulation signals to adjust the adsorption force.

[0015] Furthermore, the navigation and positioning system is used to achieve synchronous positioning and mapping of the device, autonomous navigation, and precise positioning of detection points.

[0016] Furthermore, the guided wave excitation acquisition module is located in the space below the vehicle frame.

[0017] A second aspect of this invention discloses a method for inspecting steel structures based on magnetostrictive guided waves, comprising the following steps: S1. Plan the continuous coverage path for the area to be detected; S2. The robot moves to the starting point of the path and lowers the detection roller, so that the probe body in one of the mounting slots contacts the steel surface with constant pressure. S3. The robot moves continuously along the planned path. During the movement, the detection roller is passively rotated under the friction of the steel surface, so that the probe body on each set of mounting slots gradually sweeps across the steel surface. The guided wave excitation acquisition module cyclically sends excitation pulses to the probes in contact with the steel surface and collects the return signals to form a continuous detection data stream. At the same time, the navigation and positioning system integrates the robot's pose and the rotation angle information of the detection roller in real time to generate corresponding spatial coordinates for each detection moment. S4. The area scan is complete. The robot stops and lifts the detection roller to detach the probe from the surface. S5. Process and analyze the continuous detection data stream with synchronized location information to generate a defect distribution map or three-dimensional imaging map covering the scanned area.

[0018] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects: 1. The probe assembly employs two permanent magnets with opposing magnetic poles, forming a concentrated and stable strong bias magnetic field, which greatly improves the excitation efficiency of the magnetostrictive effect. The excitation / receiving coil is placed between the two magnetic poles, resulting in better magnetic field superposition. The use of a wear-resistant elastic dry coupling pad ensures good acoustic coupling, avoids the inconveniences of using liquid coupling agents at high altitudes and on vertical surfaces, and extends the probe's lifespan. This ensures the high performance and long lifespan of the core components of the detection system.

[0019] 2. A closed-loop feedback control system, comprised of a force sensor integrated into the probe actuator and an onboard main control unit, precisely maintains a constant contact pressure between the probe assembly and the steel surface. Combined with a wear-resistant elastic dry coupling pad, this ensures high consistency in magnetic-force coupling conditions, effectively eliminating amplitude drift and phase distortion of the guided wave signal caused by pressure fluctuations. The stable coupling state improves the signal-to-noise ratio, enabling the device to achieve extremely high detection sensitivity and quantitative assessment accuracy for defects such as early fatigue cracks and micro-corrosion within steel structures.

[0020] 3. The device employs a symmetrical, independently driven movement and obstacle-crossing mechanism. Its V-shaped swing arm and adjustable pre-tensioning linkage enable the device to adaptively overcome obstacles, passively responding and smoothly traversing common surface obstacles such as welds and stiffening ribs. Simultaneously, by actively adjusting the electromagnet's attraction force through pulse width modulation (PWM) technology, an intelligent balance between strong attraction stability and low-resistance movement is achieved. This allows the device to reliably attract and autonomously move on complex and varied steel structure facades and rooftops, replacing high-risk manual high-altitude operations and significantly improving the safety of the inspection process. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 This is a schematic diagram of the main structure of the steel structure testing device provided in one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the bottom structure of the steel structure testing device provided in one or more embodiments of the present invention; Figure 3 This is a schematic diagram of the main body of the moving and obstacle-crossing mechanism in the steel structure detection device provided in one or more embodiments of the present invention; Figure 4This is a cross-sectional view of the track in the steel structure inspection device provided in one or more embodiments of the present invention; Figure 5 This is a schematic diagram of the main structure of the detection roller in the steel structure detection device provided in one or more embodiments of the present invention; Figure 6 This is an exploded view of the detection roller and probe assembly in the steel structure detection device provided in one or more embodiments of the present invention; Figure 7 This is an exploded view of the elastic telescopic rod and the probe assembly in the probe assembly of the steel structure testing device provided in one or more embodiments of the present invention; Figure 8 This is a structural diagram of the probe assembly in the steel structure detection device provided in one or more embodiments of the present invention; Figure 9 This is a structural block diagram of the integrated control system in the steel structure testing device provided in one or more embodiments of the present invention; Figure 10 This is a connection block diagram of the airborne main control unit in the steel structure testing device provided in one or more embodiments of the present invention.

[0023] Figures 1-2 In the middle: 110, vehicle frame; 130, moving and obstacle-crossing mechanism; 200, magnetostrictive guided wave detection system; 310, airborne main control unit; 320, navigation and positioning system; Figure 3 In the middle: 131, lateral mounting base; 132, tilting swing arm; 133, adjustable preload connecting rod; 134, driven wheel bracket; 135, guide tension wheel; 136, load-bearing wheel; 137, drive wheel; 138, track; 139, through drive shaft; Figure 4 Chinese: 121. Electromagnet; 138. Track; Figure 5 In the middle section: 210, probe assembly; 221, lifting drive module; 222, guide rod; 223, force sensor; 330, guided wave excitation acquisition module; 410, U-shaped frame; 420, detection roller; Figures 6-7 In the middle: 420, detection roller; 430, mounting groove; 440, elastic telescopic rod; 450, hinge; Figure 8 In the middle: 210, probe assembly; 211, permanent magnet; 212, excitation and receiving coils; 213, dry coupling pad; Figures 9-10 In the middle: 300, integrated control system; 220, probe actuator; 330, guided wave excitation acquisition module. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] As described in the background section, fatigue crack detection of large steel structures (such as bridges and factories) is crucial for ensuring their safe service. Currently, using wall-climbing robots equipped with non-destructive testing probes for automated on-machine inspection is an important development direction to replace high-risk manual inspection. However, the probe structures used in existing automated inspection devices have many design flaws, which seriously restrict the reliability, accuracy, and efficiency of the inspection results, specifically in the following aspects: Existing probes mostly use simple spring or pneumatic clamping mechanisms, which cannot maintain a constant contact pressure under actual working conditions such as uneven steel structure surfaces and weld protrusions. Pressure fluctuations cause the coupling conditions (such as the thickness of the couplant layer or the compression of the dry coupling pad) to change continuously, directly causing amplitude drift and phase distortion of the ultrasonic guided wave signal. This not only drowns out the weak reflection signals of tiny defects, causing missed detections, but also significantly reduces the accuracy of quantitative analysis based on signal amplitude to assess defect size.

[0027] Most probes are rigidly mounted and lack an adaptive adjustment mechanism. When the detection surface has local tilt, unevenness, or when the device moves on a tilted wall and generates lateral force, the probe is prone to deflection, making it impossible to ensure uniform contact between its detection surface and the steel structure surface across the entire area. This reduces the effective detection area and degrades detection performance. Furthermore, after overcoming obstacles, the probe often fails to automatically and accurately return to the optimal detection posture.

[0028] For magnetostrictive guided wave detection, the magnetic field design of the probe is particularly critical. Existing probes often suffer from problems such as insufficient or uneven distribution of the bias magnetic field strength and poor spatial coordination between the excitation and bias magnetic fields, resulting in low magnetostrictive effect excitation efficiency and poor guided wave energy conversion. At the same time, an unreasonable magnetic circuit design may cause serious magnetic field leakage, which not only reduces detection sensitivity but may also interfere with the device's own electronic system.

[0029] In long-term, large-scale automated operations, the probes suffer from insufficient wear resistance and impact resistance. For example, the dry coupling pads wear rapidly on rough surfaces, the excitation coils are easily damaged by mechanical stress during frequent clamping and movement, and the permanent magnets may demagnetize under vibration and temperature changes. These problems lead to frequent probe maintenance or replacement, increasing operating costs and reducing detection efficiency.

[0030] Existing probes are typically used as independent functional units, with low integration with mobile platforms and control systems. They generally lack monitoring capabilities for probe operating status (such as real-time pressure, temperature, and wear), and clamping force control is mostly open-loop, unable to adaptively adjust based on surface conditions. Furthermore, real-time and accurate correlation between detection data and spatial location information is also quite difficult.

[0031] Therefore, this solution provides a steel structure inspection device and working method based on magnetostrictive guided waves. The closed-loop control of the force sensor ensures constant pressure contact between the probe and the surface to stabilize the signal. The adjustable electromagnetic adsorption and adaptive obstacle-crossing track mechanism ensure stable movement and reliable inspection of the device on complex steel structure surfaces.

[0032] like Figures 1-9 As shown, the steel structure detection device based on magnetostrictive guided waves includes a vehicle frame 110, a moving and obstacle-crossing mechanism 130 on the vehicle frame 110, a magnetostrictive guided wave detection system 200 on the lower surface of the vehicle frame 110, and multiple electromagnets 121 for adsorbing steel structures on the moving and obstacle-crossing mechanism 130; and an integrated control system 300 on the vehicle frame 110.

[0033] The magnetostrictive guided wave detection system 200 includes a probe assembly 210 and a probe actuator 220 for driving the probe assembly 210 to achieve continuous scanning or fixed-point clamping detection.

[0034] The integrated control system 300 includes an airborne main control unit 310, a navigation and positioning system 320, and a guided wave excitation acquisition module 330. The airborne main control unit 310 and the navigation and positioning system 320 are located on the upper surface of the vehicle frame 110, and the guided wave excitation acquisition module 330 is located in the space below the vehicle frame 110.

[0035] The airborne main control unit 310 is electrically connected to the navigation and positioning system 320, the guided wave excitation acquisition module 330, the moving and obstacle-crossing mechanism 130, the electromagnet 121, and the probe actuator 220, respectively, and is used to control the device to move autonomously and perform detection tasks, and to synchronize the detection data with the position information.

[0036] The vehicle frame 110 provides the installation foundation and structural support for the entire device. The moving and obstacle-crossing mechanism 130 is installed on the vehicle frame 110 and is responsible for driving the device to move on the steel structure surface. Multiple electromagnets 121 are attracted to the steel structure surface by generating a magnetic field to ensure the stability of the device during movement.

[0037] The magnetostrictive guided wave detection system 200 serves as the core detection unit. Its probe assembly 210 is used to contact the steel surface to excite and receive guided waves, while the probe actuator 220 drives the probe assembly 210 to achieve continuous scanning detection in a rolling contact manner.

[0038] The integrated control system 300 serves as the core of the device's control. Its onboard main control unit 310 establishes electrical connections with the navigation and positioning system 320, the guided wave excitation acquisition module 330, the movement and obstacle-crossing mechanism 130, the electromagnet 121, and the probe actuator 220. On one hand, it acquires position information through the navigation and positioning system 320 and controls the movement and obstacle-crossing mechanism 130 to drive the device to move autonomously to the detection position. On the other hand, it controls the electromagnetic adsorption unit to maintain stable adsorption and controls the probe actuator 220 to adjust the posture of the detection roller. Simultaneously, it drives the probe assembly 210 to excite guided waves and acquire return signals through the guided wave excitation acquisition module 330. Finally, it synchronizes the acquired detection data with the position information acquired by the navigation and positioning system 320, realizing automated and precise on-machine inspection of steel structures.

[0039] The integrated control system 300 controls the excitation current of the electromagnet 121 through a pulse width modulation signal to actively adjust the attraction force. The integrated control system 300 outputs a pulse width modulation signal to the electromagnet 121. By changing the duty cycle of this signal, the average value of the excitation current input to the coil of the electromagnet 121 can be adjusted. The change in the excitation current directly changes the magnetic field strength generated by the electromagnet 121, thereby achieving precise control over the magnitude of the attraction force of the electromagnet 121.

[0040] This control method can provide sufficient adsorption force when the device needs to be stably attached to the steel structure surface, and can appropriately reduce the adsorption force to reduce movement resistance when the device needs to move or overcome obstacles. It effectively balances the adsorption stability and movement flexibility of the device, and improves the adaptability and energy utilization efficiency of the device under different working conditions.

[0041] like Figure 3 As shown, the moving and obstacle-crossing mechanism 130 is a symmetrical independent drive structure, containing a left drive unit and a right drive unit with identical structures; each drive unit includes: A side mounting base 131 is fixed to the side of the vehicle frame 110, and a drive wheel 137 is provided on the inner side of the side mounting base 131. A pair of oscillating tilting arms 132, having at least two arms, the two tilting arms 132 are arranged in an inverted "V" shape, their top ends are hinged to the lateral mounting base 131, and the bottom end of each tilting arm 132 is hinged to the corresponding driven wheel bracket 134. At least two tracked wheels are provided on the driven wheel bracket 134. The two tracked wheels include a guide tension wheel 135 installed at one end of the driven wheel bracket 134 and a load-bearing wheel 136 installed at the other end. It also has tracks 138, with track 138 surrounding guide tension wheel 135, load-bearing wheel 136 and drive wheel 137.

[0042] The top ends of the two tilting arms 132 are connected to an adjustable pretensioning link 133. The opening angle between the two tilting arms 132 is changed by the adjustable pretensioning link 133, which is used to adjust the tension of the track 138.

[0043] The left drive unit and the right drive unit of the moving and obstacle-crossing mechanism 130 have the same structure and are symmetrically arranged. The lateral mounting seat 131 in each drive unit is fixed to the side of the vehicle frame 110 to provide installation support for the entire drive unit. The V-shaped inclined swing arm 132 and the hinged lateral mounting base 131 serve as a support to bear the weight of the entire device. The driven wheel bracket 134, which is hinged to the bottom of the inclined swing arm 132, is equipped with a guide tension wheel 135 and a load-bearing wheel 136 respectively. The drive wheel 137 on the inner side of the lateral mounting base 131 provides power to drive the track 138. The track 138 surrounds the guide tension wheel 135, the load-bearing wheel 136 and the drive wheel 137 to form a transmission structure, driving the entire device to run.

[0044] like Figure 4 As shown, the electromagnets 121 embedded in the inner layer of the track 138 move with the track 138, with one or more sets of electromagnets always facing and attracted to the steel surface. Specifically, multiple electromagnets 121 are embedded in the inner layer of the track 138 at uniform intervals and move in a cyclic manner with the track 138. To achieve reliable mobile power supply, the electromagnets 121 are connected in series inside the track and converged to a specially designed flexible wire with redundant length. The length of this wire is precisely calculated to ensure that the cable remains slack during the complete circumferential rotation of the track 138, avoiding fatigue breakage or interference with track movement due to tension. The electrical terminals of the wire are ultimately guided to a fixed terminal block on the vehicle frame 110, where a set of highly reliable conductive slip rings is connected. This conductive slip ring provides a continuous and stable electrical connection between the electromagnet circuit on the rotating track and the integrated control system 300 on the fixed vehicle body, thereby allowing the control system to dynamically adjust the excitation current of each electromagnet via PWM signals.

[0045] When the drive wheel 137 drives the track 138 to rotate, the guide tension wheel 135 ensures the tension of the track 138, and the load-bearing wheel 136 bears part of the weight of the device. When encountering obstacles, the two drive units can move independently, and the single-sided tilting arm 132 can adjust its posture according to the obstacle situation to ensure that the track 138 is always in contact with the steel surface, so as to achieve smooth movement and obstacle crossing.

[0046] like Figure 3 As shown, when the guide tension wheel 135 encounters an obstacle, the force exerted by the obstacle forces the driven wheel bracket 134 and the tilting arm 132 to overcome the preload of the adjustable preload link 133 and open outward, thereby achieving adaptive obstacle crossing.

[0047] When the guide tension wheel 135 comes into contact with an obstacle, the obstacle will exert an outward force on the guide tension wheel 135. This force is transmitted through the guide tension wheel 135 to the driven wheel bracket 134, and then acts on the tilting swing arm 132 which is hinged to the driven wheel bracket 134. When the force is greater than the preload applied to the tilting arm 132 by the adjustable preload link 133, it will force the tilting arm 132 to open outward around the hinge point between its top and the side mounting base 131, while driving the driven wheel bracket 134 and the guide tension wheel 135 to rise upward, so that the guide tension wheel 135 can cross the obstacle. Once the guide tension wheel 135 has completely passed the obstacle, the force exerted by the obstacle disappears. Under the preload of the adjustable preload linkage 133, the tilting arm 132, the driven wheel bracket 134, and the guide tension wheel 135 return to their initial positions. The entire obstacle-crossing process does not require additional sensor detection or complex control commands. It is completed entirely by the passive response of the mechanical structure, which is fast and reliable, ensuring the device's passability on complex steel structure surfaces.

[0048] like Figure 4 As shown, the moving and obstacle-crossing mechanism 130 also includes a through drive shaft 139, a drive gear 141, a driven gear 142, and a drive motor 143. The two ends of the through drive shaft 139 pass through the left and right side mounting seats 131 and are fixedly connected to the drive wheels 137 on both sides. The drive gear 141 is installed in the middle of the through drive shaft 139. The driven gear 142 meshes with the drive gear 141. The output shaft of the drive motor 143 is connected to the driven gear 142.

[0049] The two ends of the through drive shaft 139 pass through the side mounting seats 131 on the left and right sides and are fixedly connected to the drive wheels 137 on both sides, so that the left and right drive wheels 137 can rotate synchronously with the through drive shaft 139; the drive gear 141 is installed in the middle of the through drive shaft 139, and the driven gear 142 that meshes with the drive gear 141 is connected to the output shaft of the drive motor 143, forming a complete power transmission path.

[0050] During operation, the rotational power output by the drive motor 143 is transmitted to the driven gear 142 through the output shaft. The driven gear 142 drives the meshing drive gear 141 to rotate. The drive gear 141 further drives the through drive shaft 139 to rotate, and finally drives the two drive wheels 137 to rotate synchronously. This avoids the device from deviating due to the difference in speed between the left and right drive wheels, ensuring the stability of straight-line driving. At the same time, the transmission structure is compact and has high power transmission efficiency.

[0051] The probe actuator 220 includes a lifting drive module 221. The actuating end of the lifting drive module 221 is connected to the probe assembly 210 via a U-shaped frame 410. A force sensor 223 is provided between the probe assembly 210 and the U-shaped frame 410. The inner side of the U-shaped frame 410 is rotatably connected to the detection roller 420. The outer wall of the detection roller 420 is provided with multiple sets of mounting grooves 430 arranged axially. Each mounting groove 430 is provided with multiple probe bodies arranged in parallel. The back of each probe body is hinged to one end of an elastic telescopic rod 440 via a hinge 450. The other end of the elastic telescopic rod 440 is fixedly connected to the bottom of the mounting groove 430. Under the drive of the lifting drive module 221, the probe assembly 210 moves closer to or away from the steel structure surface along the direction of the multiple guide rods 222, so that the probe body on each set of mounting grooves 43 contacts the steel surface.

[0052] like Figures 5-7 As shown, the probe actuator 220 includes a lifting drive module 221, four guide rods 222, and a U-shaped frame 410 disposed below it. The lifting drive module 221 is used to drive the entire U-shaped frame 410 and the components mounted on it to perform vertical lifting and lowering movements; the upper ends of the four guide rods 222 are fixedly connected to the upper part of the U-shaped frame 410, and the lower ends are axially movable and pass through corresponding channels opened on the outer edge of the bottom of the lifting drive module 221, serving a guiding function.

[0053] A freely rotatable detection roller 420 is mounted on the inner side of the U-shaped frame 410 via bearings. The outer wall of the detection roller 420 has at least one axially extending mounting groove 430. Multiple probe bodies are distributed and mounted in each mounting groove 430 along the axial direction of the detection roller. The back of each probe body is hinged to one end of an elastic telescopic rod 440 via a hinge 450. The other end of the elastic telescopic rod 440 is fixedly connected to the bottom of the mounting groove 430.

[0054] Multiple probe bodies, together with corresponding hinges 450 and elastic telescopic rods 440, and detection rollers 420, form a probe assembly 210.

[0055] The lifting drive module 221 integrates a force sensor 223 at its actuating end, and the force sensor 223 is electrically connected to the airborne main control unit 310. When continuous scanning detection is required, the lifting drive module 221 drives the detection roller 420 to descend until the dry coupling pad at the bottom of the probe assembly 210 contacts the steel surface.

[0056] During the robot's movement, the detection roller 420 rotates under the action of friction, causing the probe assemblies 210 on it to roll sequentially over the steel surface. When each probe assembly 210 contacts the steel surface, the elastic telescopic rod 440 on its back is compressed and retracts, and the angle is adaptively adjusted by the hinge 450 to ensure that the dry coupling pad maintains a good fit with the possibly uneven steel surface.

[0057] Force sensor 223 monitors the overall pressure, and onboard main control unit 310 controls lifting drive module 221 according to feedback signal to keep the detection roller at a constant downward pressure, thereby ensuring that all working probe assemblies 210 have basically consistent contact pressure during scanning, and realizing high-quality, continuous guided wave excitation and signal reception.

[0058] When testing is required, the lifting drive module 221 drives the probe assembly 210 to move downward until the dry coupling pad contacts the steel surface; as the probe assembly 210 continues to move downward, the reaction force of the steel surface on the probe assembly 210 gradually increases, and the force sensor 223 detects the pressure value in real time and transmits the detection signal to the airborne main control unit 310. The airborne main control unit 310 compares the received pressure signal with the preset optimal contact pressure value. If the pressure value is less than the preset value, it controls the lifting drive module 221 to continue driving the probe assembly 210 to move downward. If the pressure value reaches the preset value, it controls the lifting drive module 221 to stop operating. During the detection process, if the pressure changes due to uneven steel surface or slight shaking of the device, the force sensor 223 will capture the change signal in time and provide feedback. The airborne main control unit 310 adjusts the action of the lifting drive module 221 according to the feedback signal. At the same time, the elastic buffer element absorbs the pressure fluctuation through slight deformation, and together maintains a constant contact pressure between the probe assembly 210 and the steel surface, ensuring the stability of guided wave excitation and reception and improving detection accuracy.

[0059] like Figure 8 As shown, each probe assembly 210 has two permanent magnets 211 with their magnetic poles facing each other, and an excitation and receiving coil 212 is arranged between the two permanent magnets 211. The bottom of the probe assembly 210 is provided with a dry coupling pad 213 made of wear-resistant elastic material.

[0060] The two permanent magnets in the probe assembly 210 are placed with their magnetic poles facing each other. By utilizing the principle of like poles repulsion, a stable and strong static bias magnetic field is formed in the local area in contact with the steel surface, providing a magnetic field basis for the generation of the magnetostrictive effect. The excitation and receiving coils, located between two permanent magnets, are the core components for realizing guided wave excitation and signal reception. The dry coupling pad at the bottom of the probe assembly 210 is made of wear-resistant elastic material and is used to fill the microscopic gap between the probe and the steel surface.

[0061] When it is necessary to excite the guided wave during operation, the guided wave excitation acquisition module 330 sends a high-frequency electrical pulse to the excitation and receiving coils. The high-frequency electrical pulse generates an alternating magnetic field around the excitation and receiving coils. After the alternating magnetic field is superimposed with the static bias magnetic field generated by the permanent magnet, the material in the corresponding area of ​​the steel structure surface undergoes a magnetostrictive effect. The deformation of the material generates an ultrasonic guided wave that propagates along the steel surface. When the ultrasonic guided wave encounters a defect during propagation, it will be reflected to form a returning guided wave. The returning guided wave acts on the steel structure material, causing a change in the local magnetic field. The changing magnetic field will cause the excitation and receiving coils to cut the magnetic lines of force, thereby generating an induced electrical signal in the excitation and receiving coils. The guided wave excitation acquisition module 330 acquires the induced electrical signal and transmits it to the airborne main control unit 310 to complete the defect detection. The dry coupling pad ensures good contact between the probe and the steel surface throughout the process, reduces magnetic field loss, and avoids wear caused by direct friction between the probe and the steel surface, thus protecting the probe and the steel surface.

[0062] This scheme employs a "pole-to-pole" layout (usually two magnets with their N poles or S poles facing each other), creating a "magnetic field convergence zone" with highly concentrated and extremely dense magnetic field lines in the narrow air gap between the magnets. This magnetic field is applied to the surface of the steel structure to be tested below, bringing it to a sensitive state of "magnetization saturation" or near-saturation, preparing it for subsequent waveguide excitation.

[0063] The coil is placed between two opposing magnetic poles, located in the core region of the aforementioned static strong magnetic field. When a pulsed current passes through the coil, the direction of the generated alternating magnetic field is highly consistent with (or opposite to) the direction of the static bias magnetic field. Through coaxial superposition, the total magnetic field acting on the steel undergoes the maximum amplitude intensity change.

[0064] According to the principle of magnetostriction, drastic changes in magnetic field strength will induce periodic micro-deformation (magnetostrictive strain) in steel materials, thereby exciting stronger ultrasonic guided waves. Therefore, the arrangement of the permanent magnets and coils described above achieves optimal coupling between the static magnetic field and the dynamic excitation magnetic field.

[0065] The excitation and receiving coils function as both transmitters and receivers of the signal. When a guided wave encounters a defect and is reflected back, or undergoes a mode transition during propagation, the returning mechanical wave (stress wave) causes a slight change in the magnetization state of the local steel (diamagnetostriction). This change in magnetic state also occurs within the strong static bias magnetic field environment established by two permanent magnets. Even minor disturbances in the magnetic field environment induce significant electrical signals in the coils. The coils can effectively "capture" these magnetic field disturbances and convert them into measurable electrical signals, thereby greatly improving the receiving sensitivity.

[0066] like Figure 8As shown, the navigation and positioning system 320 is used to achieve synchronous positioning and mapping, autonomous navigation, and precise positioning of detection points for the device. The operation of the navigation and positioning system 320 revolves around three core functions: synchronous positioning and mapping, autonomous navigation, and precise positioning of detection points.

[0067] In terms of simultaneous positioning and mapping, the navigation and positioning system 320 acquires environmental information of the steel structure surface around the device through built-in sensors such as lidar and vision sensors, builds a map of the environment in which the device is located in real time, and calculates its own position on the map by combining the device's movement data, so as to realize the simultaneous positioning and mapping.

[0068] In terms of autonomous navigation, the airborne main control unit 310 plans the optimal movement path of the device based on the map constructed by the navigation and positioning system 320 and the preset detection area. The navigation and positioning system 320 feeds back the current position and attitude information of the device to the airborne main control unit 310 in real time. The airborne main control unit 310 controls the movement and obstacle crossing mechanism 130 to adjust the movement direction and speed based on the information, so that the device moves autonomously along the planned path.

[0069] In terms of precise positioning of detection points, the navigation and positioning system 320 further improves the positioning accuracy through high-precision sensors (such as inertial measurement units, encoders, etc.). When the device performs continuous scanning detection, the system binds the guided wave signal data packets collected at each moment with the position of the robot at the same moment, as well as the specific contact point coordinates of the probe calculated based on the rotation angle of the detection roller 420.

[0070] Finally, the navigation and positioning system 320 transmits the location information of each detection point to the airborne main control unit 310. The airborne main control unit 310 associates the location information with the guided wave signal data of the corresponding detection point, providing accurate spatial coordinates for subsequent defect analysis and defect distribution map generation.

[0071] The steel structure inspection method based on magnetostrictive guided waves utilizes the aforementioned steel structure inspection device based on magnetostrictive guided waves, and includes the following steps: S1. Plan the continuous coverage path for the area to be detected; S2. The robot moves to the starting point of the path and lowers the detection roller, so that the probe body in one of the mounting slots contacts the steel surface with constant pressure. S3. The robot moves continuously along the planned path. During the movement, the detection roller is passively rotated under the friction of the steel surface, so that the probe body on each set of mounting slots gradually sweeps across the steel surface. The guided wave excitation acquisition module cyclically sends excitation pulses to the probes in contact with the steel surface and collects the return signals to form a continuous detection data stream. At the same time, the navigation and positioning system integrates the robot's pose and the rotation angle information of the detection roller in real time to generate corresponding spatial coordinates for each detection moment. S4. The area scan is complete. The robot stops and lifts the detection roller to detach the probe from the surface. S5. Process and analyze the continuous detection data stream with synchronized location information to generate a defect distribution map or three-dimensional imaging map covering the scanned area.

[0072] The aforementioned solution utilizes a closed-loop feedback control system comprised of a force sensor integrated into the probe actuator and an onboard main control unit to precisely maintain a constant contact pressure between the probe assembly and the steel surface. Combined with a wear-resistant elastic dry coupling pad, it ensures a high degree of consistency in the magnetic-force coupling conditions, effectively eliminating amplitude drift and phase distortion of the guided wave signal caused by pressure fluctuations. This stable coupling state improves the signal-to-noise ratio, enabling the device to achieve extremely high detection sensitivity and quantitative assessment accuracy for defects such as early fatigue cracks and micro-corrosion within steel structures.

[0073] The device employs a symmetrical, independently driven movement and obstacle-crossing mechanism. Its V-shaped swing arm and adjustable pre-tensioning linkage enable the device to adaptively overcome obstacles, passively responding and smoothly traversing common surface obstacles such as welds and stiffening ribs. Simultaneously, by actively adjusting the electromagnet's attraction force through pulse width modulation (PWM) technology, an intelligent balance between strong attraction stability and low-resistance movement is achieved. This allows the device to reliably attract and autonomously move on complex and varied steel structure facades and rooftops, replacing high-risk manual high-altitude operations and significantly improving the safety of the inspection process.

[0074] The integrated control system combines navigation and positioning, autonomous motion control, and synchronous data acquisition. It can autonomously navigate to the detection point according to a preset path or map, automatically completing the entire detection process of "positioning-clamping-excitation / acquisition-pickup-movement," and real-time correlated the guided wave signal with high-precision spatial position information. The entire process requires no manual intervention, achieving standardization and digitization of the detection operation, significantly reducing labor intensity, and improving detection efficiency and coverage. It is particularly suitable for large-scale rapid screening of large steel structures.

[0075] Each probe body employs two permanent magnets with opposing magnetic poles, forming a concentrated and stable strong bias magnetic field, which greatly improves the excitation efficiency of the magnetostrictive effect. The excitation / receiving coil is placed between the two magnetic poles, resulting in even better magnetic field superposition. The use of a wear-resistant, elastic dry coupling pad ensures good acoustic coupling while avoiding the inconveniences of using liquid coupling agents at high altitudes or on vertical surfaces, and extends the probe's lifespan. This ensures the high performance and long lifespan of the core components of the detection system.

[0076] The device highly integrates a mobile platform, adsorption system, detection system, and control system. All detection data comes with precise spatiotemporal coordinates and can be directly transmitted to a ground station or cloud for batch processing, analysis, and visualization, generating intuitive defect distribution maps or structural health status cloud maps. This provides a solid data foundation for the full life-cycle health monitoring, maintenance decisions, and digital asset management of steel structures.

[0077] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A steel structure inspection device based on magnetostrictive guided waves, characterized in that, Including the vehicle body frame, on which are provided: The moving and obstacle-crossing mechanism is used to move the device on the steel structure surface. Both the moving and obstacle-crossing mechanisms are equipped with electromagnets, which cause the device to adhere to the steel structure surface. A magnetostrictive guided wave detection system includes a probe assembly and a probe actuator for driving the probe assembly to achieve continuous scanning detection; the probe assembly includes at least two permanent magnets arranged side by side with opposite magnetic poles, an excitation and receiving coil is provided between the two permanent magnets, and a dry coupling pad is provided at the bottom of the permanent magnet near the surface of the steel structure. An integrated control system is configured to: control the movement of the device, and / or control the excitation and receiving coil to generate guided waves and receive return signals, and / or synchronize position information.

2. The steel structure inspection device based on magnetostrictive guided waves as described in claim 1, characterized in that, The movement and obstacle-crossing mechanism includes a left drive unit and a right drive unit with identical structures; each drive unit includes: A side mounting bracket is attached to the side of the vehicle frame, and a drive wheel is provided on the side mounting bracket; The tilting arm has at least two arms, which are arranged in an inverted "V" shape. The top end is hinged to the side mounting base, and the bottom end is hinged to the corresponding driven wheel bracket. The driven wheel bracket is provided with a guide tension wheel and a load-bearing wheel. Tracks, surrounding the guide tension wheel, load-bearing wheel and drive wheel, with electromagnets installed on the inner side of the track or on the track support.

3. The steel structure inspection device based on magnetostrictive guided waves as described in claim 2, characterized in that, The drive unit also includes an adjustable preload link, which connects the top ends of the two tilting arms.

4. The steel structure inspection device based on magnetostrictive guided waves as described in claim 1, characterized in that, The moving and obstacle-crossing mechanism also includes a through drive shaft that passes through the vehicle frame and is connected to corresponding drive wheels at both ends. The drive gear is located in the middle of the through drive shaft and meshes with the driven gear. The driven gear is connected to the output shaft of the drive motor. The drive motor drives the through drive shaft and the drive wheels to rotate through the driven gear and the drive gear, thereby driving the tracks.

5. The steel structure inspection device based on magnetostrictive guided waves as described in claim 1, characterized in that, The probe actuator includes a lifting drive module. The actuating end of the lifting drive module is connected to the probe assembly via a U-shaped frame. A force sensor is provided between the probe assembly and the U-shaped frame. A detection roller is rotatably connected to the inner side of the U-shaped frame. Multiple sets of mounting slots are provided on the outer wall of the detection roller along the axial direction. Multiple probe bodies are arranged in parallel in each mounting slot. The back of each probe body is hinged to one end of an elastic telescopic rod through a hinge. The other end of the elastic telescopic rod is fixedly connected to the bottom of the mounting slot. Driven by the lifting drive module, the probe assembly moves closer to or away from the steel structure surface along the direction of the multiple guide rods, so that the probe body in each mounting slot of each set contacts the steel surface.

6. The steel structure inspection device based on magnetostrictive guided waves as described in claim 1, characterized in that, The dry coupling pad is made of abrasion-resistant elastic material.

7. The steel structure inspection device based on magnetostrictive guided waves as described in claim 1, characterized in that, The integrated control system includes an airborne main control unit, a navigation and positioning system, and a guided wave excitation acquisition module. The airborne main control unit is electrically connected to the navigation and positioning system, the guided wave excitation acquisition module, the moving and obstacle-crossing mechanism, the electromagnet, and the probe actuator, respectively. It is used to control the movement of the device and to control the excitation and receiving coils to generate guided waves and receive return signals through the guided wave excitation acquisition module. At the same time, it synchronizes the detection data with the position information obtained by the navigation and positioning system.

8. The steel structure inspection device based on magnetostrictive guided waves as described in claim 7, characterized in that, The integrated control system controls the excitation current of the electromagnet through pulse width modulation signals to adjust the adsorption force.

9. The steel structure inspection device based on magnetostrictive guided waves as described in claim 7, characterized in that, The navigation and positioning system is used to achieve synchronous positioning and mapping, autonomous navigation, and precise positioning of detection points for the device.

10. A method for steel structure inspection based on the apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Plan the continuous coverage path for the area to be detected; S2. The robot moves to the starting point of the path and lowers the detection roller, so that the probe body in one of the mounting slots contacts the steel surface with constant pressure. S3. The robot moves continuously along the planned path. During the movement, the detection roller is passively rotated under the friction of the steel surface, so that the probe body on each set of mounting slots gradually sweeps across the steel surface. The guided wave excitation acquisition module cyclically sends excitation pulses to the probes in contact with the steel surface and collects the return signals to form a continuous detection data stream. At the same time, the navigation and positioning system integrates the robot's pose and the rotation angle information of the detection roller in real time to generate corresponding spatial coordinates for each detection moment. S4. The area scan is complete. The robot stops and lifts the detection roller to detach the probe from the surface. S5. Process and analyze the continuous detection data stream with synchronized location information to generate a defect distribution map or three-dimensional imaging map covering the scanned area.

Images