Rotary pipeline interior detection robot, device and method based on electromagnetic eddy current detection

Abstract

The invention discloses a rotary pipeline interior detection robot, device and method based on electromagnetic eddy current detection, and belongs to the technical field of pipeline robots. The robot comprises an outer shell, a rotatable rotating inner shell is arranged in the outer shell, mounting bases are arranged at the two ends of the outer shell respectively, a motor is mounted on the mounting base at the rear end, and a rotating shaft of the motor is connected with the rear end of the rotating inner shell. The front-end mounting base and the rear-end mounting base are each provided with a plurality of supporting and moving assemblies, a coil assembly is installed outside the front-end mounting base, and a phase-locked amplification PCB, a signal generator PCB, a battery and an STM32 development board are arranged in the rotary inner shell. 360-degree continuous scanning detection in a small-pipe-diameter pipeline is achieved, the defect detection rate is effectively increased, a self-adaptive supporting structure ensures that the robot stably advances in different pipe diameters and bent pipe sections, the whole process of excitation signal generation, eddy current signal extraction and data processing is completed in a limited space through integrated circuit design, and the detection efficiency is improved. And a feasible technical scheme is provided for detection in the small-diameter pipeline.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pipeline robots, and particularly relates to a rotary pipeline internal detection robot based on electromagnetic eddy current detection, a device and a method. BACKGROUND

[0002] As an important infrastructure of modern industry, pipelines play a key role in the field of energy transportation such as oil and natural gas. However, defects such as corrosion and cracks are prone to occur on the inner wall of the pipeline during long-term service, which seriously affects the safe operation of the pipeline. The traditional pipeline external detection technology has a detection blind area and cannot fully evaluate the internal condition of the pipeline. The current mainstream pipeline internal detection technology mainly includes the magnetic flux leakage method and the ultrasonic detection method, but these methods have obvious limitations: the magnetic flux leakage method can only detect surface defects and is easily disturbed; the ultrasonic method needs coupling agent and the detection depth is limited, especially for buried pipelines, which requires large-scale excavation and has high implementation cost.

[0003] The electromagnetic eddy current detection technology is attracting attention due to its unique advantages in detecting small-diameter pipelines. This technology can effectively identify the defects on the inner wall of the pipeline by inducing eddy current in the conductor through alternating magnetic field. However, the existing electromagnetic eddy current detection device still faces major challenges in miniaturization, detection sensitivity, and bending pipe passability. Especially for small-diameter pipelines with a diameter less than 150mm, the existing detection equipment cannot meet the space constraint requirements, resulting in a lack of effective internal detection means for a large number of small-diameter pipelines.

[0004] In the field of pipeline robot technology, the existing communication methods have obvious defects: wired communication is limited by cable friction resistance, which seriously affects the detection distance; wireless communication faces signal attenuation and electromagnetic shielding problems. In addition, traditional pipeline detection robots generally have the technical bottlenecks of insufficient power and poor walking stability, which are difficult to adapt to the detection requirements in complex pipeline environments. Especially in the design of rotary detection mechanism, signal processing accuracy, and equipment integration, the existing technology has not formed a perfect solution. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the existing technology, and to provide a rotary pipeline internal detection robot based on electromagnetic eddy current detection, a device and a method to solve the problems of difficult communication and poor walking stability of pipeline robots in the existing technology.

[0006] To achieve the above purpose, the following technical solutions are adopted: A rotary pipeline internal detection robot based on electromagnetic eddy current detection, comprising a shell, a coaxial and rotatable rotating inner shell is arranged in the shell, a detachable front end mounting seat is arranged at the front end of the shell; a motor is arranged at the rear end of the shell, and the rotating shaft of the motor is connected with the rear end of the rotating inner shell; A plurality of support moving assemblies are installed in the front mounting seat and the rear end of the shell; The front mounting seat is provided with a detection coil disc and a fixed disc connected by a connecting shaft at two ends, the fixed disc is arranged at one end of the rotating inner shell, the detection coil disc is arranged outside the front mounting seat, a coil assembly is arranged outside the detection coil disc, the coil assembly comprises an excitation coil and a detection coil, and the rotating inner shell is internally provided with a phase-locked amplification PCB board, a signal generator PCB board, a battery and an STM32 development board; The excitation coil and the signal generator PCB board are electrically connected, and the detection coil and the phase-locked amplification PCB board are electrically connected.

[0007] The further improvement of the application is that: Preferably, two mirror-symmetrical support moving assemblies are installed in the front mounting seat and the rear end of the shell.

[0008] Preferably, the support moving assembly comprises a support wheel with a gear, a rack and a compression spring, one end of the rack abuts against the compression spring, and the gear in the support wheel with the gear is engaged with the rack. The compression spring and the rack are fixedly arranged in a cavity formed in the front mounting seat or the rear end of the shell, and the support wheel with the gear protrudes from the front mounting seat or the rear end of the shell.

[0009] Preferably, the coil assembly is fixedly arranged on the detection coil disc by a coil fixing piece.

[0010] Preferably, the shell, the rotating inner shell, the front mounting seat and the rear mounting seat are composed of two parts.

[0011] Preferably, the signal generator PCB board adopts a DDS method and is composed of an STM32F103C8T6 single-chip microcomputer, an AD9834 signal generator chip and a 75MHz crystal oscillator.

[0012] Preferably, the phase-locked amplification PCB board is an AD8302 chip.

[0013] A rotating type pipeline internal detection system based on electromagnetic eddy current detection of the above-mentioned robot, comprising: A signal sending module is used for sending two-way frequency equal sine signals, which are excitation signals and reference signals respectively; the excitation signals are used for being sent out by the excitation coil to perform defect detection; A phase-locked amplification module is used for receiving detection signals and reference signals, extracting the amplitude ratio and phase difference of the detection signals and the reference signals, and obtaining the detected defect; the detection signals are signals returned by defect detection; Signal processing and acquisition module receives the amplitude ratio and phase difference of the detection signal and reference signal, and calculates the defects of the sample to be detected.

[0014] Preferably, it further comprises a detection signal preprocessing module for amplifying the detection signal. The PC end or oscilloscope is used for displaying the detected defect information.

[0015] A detection method of the above detection system, a signal generator PCB generates two same-frequency sinusoidal signals, one of which drives the excitation coil, and the other of which is input into a lock-in amplifier PCB as a reference signal, the signal of the detection coil is also input into the lock-in amplifier PCB, the amplitude ratio and phase difference of the two signals are extracted by the lock-in amplifier PCB, and the defect information is obtained by outputting a direct current voltage to an STM32 development board.

[0016] Compared with the prior art, the present application has the following beneficial effects: The application discloses a rotary pipeline internal detection robot based on electromagnetic eddy current detection.

[0017] Further, the support wheel of the present application adopts precise cooperation of gears, racks and springs, so that the support wheel can be radially contracted. DETAILED DESCRIPTION

[0018] Figure 1 A horizontal placement structure schematic diagram of the rotary pipeline internal detection robot based on electromagnetic eddy current technology.

[0019] Figure 2 A vertical placement structure schematic diagram of the rotary pipeline internal detection robot based on electromagnetic eddy current technology.

[0020] Figure 3 A schematic diagram of the electromagnetic eddy current detector device of the present application.

[0021] Figure 4 A schematic diagram of the electromagnetic eddy current detection principle of the present application.

[0022] The components include: 1. Support wheel with gears at the end; 2. Rack; 3. Compression spring; 4. Detection coil disc; 5. Coil assembly; 6. Coil fixing component; 7. Front mounting base; 8. Fixing disc; 9. Housing; 10. Signal generator PCB board; 11. Battery; 12. STM32 development board; 13. Rotating inner shell; 14. Phase-locked amplifier PCB board; 15. Motor; 16. Front cover; 17. Rear cover; 18. Connecting shaft. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings: Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] See Figure 1 and Figure 2 This invention discloses a rotary pipeline inspection robot based on electromagnetic eddy current detection. The inspection chamber has a double-layer cylindrical structure. The outer shell 9 does not rotate during movement, serving a protective and support function. The inner rotating shell 13 is coaxially fixed with the detection coil disk 4 and is driven by a motor. It rotates slowly during the robot's linear movement to achieve omnidirectional pipeline inspection. Specifically, the main structure of the robot includes a cylindrical outer shell 9, inside which is a cylindrical rotating shell 13. The rotating shell 13 is equipped with a support shaft, allowing it to rotate relative to the outer shell 9. The rotating shell 13 is a rotating carrier arranged coaxially with the outer shell 9. It can be a hollow cylindrical structure with a front cover 16 and a rear cover 17 at both ends. It rotates relative to the outer shell through bearings and is used to carry the detection circuit and power supply unit.

[0025] A front mounting base 7 is installed at the front end of the outer shell 9. The front mounting base 7 is connected to the front end of the outer shell 9 by bolts. A detection coil disk 4 and a fixed disk 8 are respectively provided at both ends of the front mounting base 7 and connected by a connecting shaft 18. The connecting shaft 18 is fitted inside the front mounting base 7. The front end of the rotating inner shell 13 is connected to the rear end face of the fixed disk 8. The front mounting base 7 is fixedly inserted between the fixed disk 8 and the detection coil disk 4 to fix and support the two disks, thus providing the structural basis for the rotation of the inner and outer layers. The cavity formed by the connecting shaft of the detection coil disk 4 and the fixed disk 8 and the front mounting base 7 is connected by a bearing, allowing the detection coil disk 4 and the fixed disk 8 to rotate relative to the front mounting base 7. This structure allows the fixed disk 8, the connecting shaft 18, and the detection coil disk 4 to rotate synchronously when the rotating inner shell 13 rotates.

[0026] A coil assembly 5, comprising an excitation coil and a detection coil, is mounted on the front end of the detection coil disk 4 via a coil fixing member 6. The coil assembly 5 is fixedly mounted on the detection coil disk 4 via the coil fixing member 6. The coil fixing member 6 is a mechanical structure used to rigidly connect the coil assembly 5 to the detection coil disk 4. Specifically, it can be implemented using an aluminum alloy clamp with threaded holes, where the coil assembly 5 is clamped to a pre-set mounting position on the detection coil disk 4 by bolt tightening. This structure prevents displacement of the coil during rotation, ensuring the stability of the detection signal.

[0027] Two mirror-symmetrical support and moving assemblies are installed in the front mounting base 7. Each support and moving assembly includes a support wheel 1 with gears, a rack 2, and a compression spring 3. One end of the rack 2 abuts against the compression spring 3, and the gear in the support wheel 1 meshes with the rack 2. The support wheel 1 protrudes from the outer wall of the front mounting base 7.

[0028] The rotating inner shell 13 is housed inside a slot, and from front to back, it contains a phase-locked amplifier PCB board 14, a signal generator PCB board 10, a battery 11, and an STM32 development board 12.

[0029] A motor 15 is located in the middle of the rear end of the outer casing 9. The shaft of the motor 15 is connected to the rear end of the rotating inner casing 13, enabling it to drive the rotating inner casing 13 and its internal mounting components to rotate. The shaft of the motor 15 is fixedly connected to the tail shaft of the two rotating inner casings 13 via a coupling. Two axial cavities are formed on both sides of the motor 15, each used to install two mirror-symmetrical support and moving assemblies. Each support and moving assembly includes a support wheel 1 with gears, a rack 2, and a compression spring 3. One end of the rack 2 abuts against the compression spring 3, and the gear in the support wheel 1 meshes with the rack 2. The support wheel 1 at the rear end of the outer casing 9 protrudes from the outer side wall of the outer casing 9. The power output shaft of the motor 15 is connected to the rear end of the rotating inner casing 13, enabling the motor 15 to drive the rotating inner casing 13, the fixed disk 8, and the detection coil disk 4 to rotate.

[0030] This invention comprises four sets of supporting and moving components, arranged perpendicularly to each other. Specifically, the line connecting the positions of the two wheel components at the front end of the robot is perpendicular to the line connecting the positions of the two wheel components at the rear end of the robot. When the invention enters the pipe, the support wheel 1 is in an inwardly tightened state. After entering the pipe to be tested, before the support wheel touches the pipe wall, the compressed spring 3 extends, pushing the rack 2 to drive the gear of the support wheel with a gear at its end to rotate. The support wheel then opens to contact the pipe wall, thereby achieving smooth movement.

[0031] It should be understood that the front mounting base 7 and the rear end of the housing 9 in this invention are provided with corresponding cavities for mounting the geared support wheel 1, rack 2, and compression spring 3. The cavity where the geared support wheel 1 is mounted ensures the operability of its rotational movement. The outer end of the geared support wheel 1 is the support wheel, and the inner end of the rotation shaft at the center of the support wheel is gear-shaped. The support wheel of this invention uses a precise fit of gears, racks, and springs, allowing the support wheel to retract radially.

[0032] Specifically, when the motor-driven rotating inner shell 13 rotates circumferentially relative to the outer shell 9, the coil assembly 5 outside the front mounting base 7 rotates synchronously, achieving spiral scanning detection of the inner wall of the pipe. The spring in the supporting moving assembly pushes the support wheel against the pipe wall via a rack, ensuring the robot's centered positioning while reducing motion resistance. The integrated signal generator PCB board 10 inside the rotating inner shell 13 generates a specific frequency excitation signal, which is transmitted to the excitation coil to generate an alternating magnetic field. When a defect exists in the pipe, the change in the eddy current field is captured by the detection coil, and the signal is processed by a lock-in amplifier circuit before being analyzed by the STM32 development board. The battery pack provides independent power to each electronic component, preventing cable tangling during rotation.

[0033] Compared to existing technologies, the split-type rotating structure resolves the conflict between circumferential scanning of the detection module and stable operation of the power supply unit. The relative movement between the inner and outer shells enables cableless signal transmission. The spring-preloaded support mechanism ensures adaptive pipe diameter while reducing interference to the detection signal compared to traditional rigid support wheels. The integrated circuit layout concentrates signal generation, phase-locked amplification, and the main control module within the rotating inner shell, shortening the signal transmission path and reducing the impact of electromagnetic interference on detection accuracy compared to distributed circuit designs.

[0034] The outer shell 9 of this invention does not rotate, while the rotating inner shell is fixed to the detection coil disk and each detector PCB. Rotation during movement reduces the number of eddy current detection coils. This enables 360-degree continuous scanning detection within small-diameter pipes, and the rotating coil arrangement effectively improves the defect detection rate. An adaptive support structure ensures stable movement of the robot across different pipe diameters and bends, while the separate power supply and signal processing system avoids the risk of failure due to cable entanglement. The integrated circuit design completes the entire process of excitation signal generation, eddy current signal extraction, and data processing within a limited space, providing a feasible technical solution for corrosion detection in small-diameter pipes.

[0035] The coil assembly 5 includes an excitation coil and a detection coil, both wound with copper wire. The excitation coil is cylindrical, while the detection coil is solid cylindrical and placed within the hollow portion of the excitation coil. Traditional pipeline inspection robots typically fix the detection coil directly to the robot body, leading to eccentric vibrations during rotation. This solution, however, achieves decoupled rotation between the coil assembly and the robot body through an independently designed detection coil disk and a fixed disk structure, resolving the coil jitter problem caused by the rotational inertia of the overall structure. Compared to existing technologies using flexible couplings, the rigid connecting shaft structure is more suitable for small-diameter pipe space constraints, avoiding the increased volume caused by additional buffer mechanisms. Through the above technical solution, this application achieves stable rotational detection of the coil assembly within the pipeline, solving the signal interference problem caused by the overall rotation of traditional structures. The independent rotation design of the detection coil disk enhances the system's adaptability to small-diameter pipe environments, and the rigid transmission characteristics of the connecting shaft ensure rotational accuracy and signal transmission reliability. The transitional connection structure of the fixed disk simplifies the assembly relationship between the rotating inner shell and the front-end mounting base, facilitating modular and rapid disassembly and maintenance.

[0036] In a specific embodiment of the present invention, the signal generator PCB board and the excitation coil are electrically connected, and the detection coil and the lock-in amplifier PCB board are electrically connected. The sinusoidal excitation signal generated by the signal generator PCB board directly drives the excitation coil through the electrical connection, causing it to generate an alternating magnetic field inside the pipe. When a defect exists in the pipe, the magnetic field distribution changes, and the detection coil senses the change in the eddy current signal and generates a corresponding detection signal. This signal is transmitted to the lock-in amplifier PCB board through the electrical connection, where it is synchronized with the reference signal provided by the signal generator to extract the amplitude ratio and phase difference parameters, thereby accurately reflecting the defect characteristics.

[0037] In a specific embodiment of the present invention, a rotary pipeline inspection robot based on electromagnetic eddy current detection is provided, wherein the outer shell 9, the rotating inner shell 13, and the front mounting base 7 are each composed of two parts.

[0038] The two-part composition refers to the modular structure of each component, achieved through detachable connectors such as bolts or clips. This design allows for quick disassembly of the outer casing and internal components, facilitating battery replacement or circuit board maintenance. The modular structure also allows for adjustments to the component assembly based on pipe diameter, adapting to different testing scenarios.

[0039] In a specific example of the present invention, the rotating inner shell 13 is composed of two shells with semi-circular cross sections.

[0040] The working process of the robot of the present invention is as follows: the motor 15 drives the detection coil disk 4, coil assembly 5, coil fixing part 6, fixing disk 8, rotating inner shell 13, phase-locked amplifier PCB board 14, signal generator PCB board 10, battery 11, and STM32 development board 12 to rotate synchronously through the motor shaft.

[0041] This invention also discloses a rotary pipe internal inspection system based on the above-mentioned robot for electromagnetic eddy current detection, comprising: The signal transmitting module is used to transmit two sinusoidal signals of equal frequency, namely an excitation signal and a reference signal; the excitation signal is used to be emitted externally through an excitation coil for defect detection; it includes a signal generator DDS and a power amplifier; A lock-in amplifier module is used to receive a detected signal and a reference signal, and extract the amplitude ratio and phase difference between the detected signal and the reference signal; the detected signal is the signal returned by defect detection. The signal processing and acquisition module receives the amplitude ratio and phase difference between the detected signal and the reference signal, and calculates the defects of the sample to be tested.

[0042] The design diagram of the electromagnetic eddy current detector system is attached. Figure 3The system consists of a signal generation module, coil assembly, detection signal preprocessing module, phase-locked amplifier module, and signal processing and acquisition module. The signal generator PCB board 10 is a circular circuit board with a 10mm diameter cutout in the center. The signal generator PCB board 10 employs DDS technology, using an STM32F103C8T6 microcontroller, an AD9834 signal generator chip, and a corresponding 75MHz crystal oscillator. A corresponding post-stage filtering circuit is also designed to ensure the stability of the excitation signal frequency and amplitude. The phase-locked amplifier PCB board 14 is also a circular circuit board with a 10mm radius cutout in the center. The phase-locked amplifier PCB board 14 uses an AD8302 chip to extract the amplitude and phase characteristics of the detection signal. Additional circuitry is added to implement the detection signal preprocessing module function, specifically performing preliminary noise filtering and amplification of the signal. By reasonably combining the AD8302 with a few other electronic components, high-precision detection signal detection can be achieved while meeting the requirements of module miniaturization and lightweight design. A circular notch is provided between the signal generator PCB board 10 and the lock-in amplifier PCB board 14 to allow wires between modules to pass through. All coil components are wound with copper wire. The excitation coil is cylindrical, and the detection coil is solid cylindrical. The detection coil fits perfectly into the hollow part of the excitation coil, forming coil assembly 5, which is fixed to coil fixture 6. The signal generator DDS is electrically connected to the excitation coil via a power amplifier, and the detection coil is electrically connected to the lock-in amplifier PCB board 14 via a low-pass filter. The STM32 development board 12 implements the signal acquisition and processing program, undertaking the signal processing and acquisition module functions. This invention uses the STM32F407ZGT6 system board as the central processing unit, combined with relevant peripheral circuits to achieve signal acquisition and storage. (Other development boards capable of performing this function can be substituted.) Furthermore, to address issues such as sensor drift and clock inaccuracy that can occur with testing equipment under extreme temperatures (-40℃ to 85℃), the signal processing and acquisition module reuses the factory calibration parameters preset by the chip manufacturer and constructs a dynamic compensation model using a linear interpolation algorithm. The detected defect signals are displayed on an oscilloscope or PC.

[0043] Furthermore, the signal generator PCB board 10 generates two sinusoidal signals of equal frequency. One signal is connected to the excitation coil, and the other is connected as a reference signal to the lock-in amplifier PCB board 14. A detection signal is generated in the detection coil and sent to the lock-in amplifier PCB board 14. The lock-in amplifier PCB board 14 extracts the amplitude ratio and phase difference between the reference signal and the detection signal and outputs them as DC voltage to the STM32 development board 12. The STM32 development board 12 software design adopts a modular polling architecture, consisting of core modules such as the main program, ADC sampling, data storage, and LCD display. The signal generator PCB board 10, the lock-in amplifier PCB board 14, and the STM32 development board 12 are all powered by the battery 11.

[0044] The principle of electromagnetic eddy current detection technology is as follows: Figure 4 As shown, under the action of an alternating sinusoidal excitation signal, eddy current signals are induced in the test sample, which in turn excite an induced magnetic field. The excitation magnetic field and the induced magnetic field form a composite magnetic field through vector superposition, and its dynamic changes generate an induced current signal in the detection coil. It is worth noting that due to the differences in electromagnetic parameters of different test samples, the eddy current distribution characteristics generated by different samples are significantly different. This difference is ultimately reflected in the changes in the amplitude, phase, and other time-frequency characteristics of the detection signal through magnetic field coupling. In particular, when the surface of the test sample has problems such as shape changes, corrosion, and cracks, its internal resistance value will also change accordingly, thereby causing changes in the amplitude and phase of the detected signal. Therefore, by identifying the amplitude and phase information of the detected signal, the defect status of the test sample can be judged.

[0045] The structure of the present invention has the following advantages: (1) Although traditional eddy current testing equipment is relatively mature, its large size limits its application to small-scale pipeline testing. The eddy current detector system development scheme provided in this patent uses AD9834, AD8302, and STM32 as the main functional chips, along with a small number of small electronic components, and arranges them on three parallel 100mm diameter circular PCB boards. This greatly reduces the size of the eddy current testing system, thereby constructing a pipeline testing robot that can be placed in a 120mm diameter circular gas pipeline, while meeting the requirements of testing accuracy and system miniaturization.

[0046] Specifically, the signal generator module (signal generator PCB board 10) adopts DDS technology, which has advantages such as high frequency resolution, precise frequency control, easy integration, and miniaturization. The lock-in amplifier module uses the AD8302 chip to extract the amplitude and phase information of the detection signal, achieving high-precision detection performance over a wide frequency range. Simultaneously, the AD8302 integrates two precisely matched logarithmic detectors onto a single chip, offering high integration advantages and meeting the miniaturization and lightweight requirements of the detection equipment. Data acquisition, processing, and storage functions are implemented using an STM32 development board. The STM32F407ZGT6 development board selected in this invention has the advantages of a compact hardware architecture and diverse peripheral interfaces, combining highly integrated miniaturized design, real-time processing capabilities, and storage expansion capabilities, making it particularly suitable for multi-channel signal acquisition tasks in space-constrained scenarios such as pipeline inspection robots.

[0047] (2) Communication is one of the main challenges restricting the development of pipeline inspection robots. Wired communication uses cables to connect the in-pipe inspection equipment to the external processing equipment, which limits the robot's travel distance and causes high cable friction. Radio electromagnetic wave communication is also unsuitable for pipeline inspection due to pipeline shielding. This invention uses an STM32 development board to achieve real-time processing and storage of inspection data. The inspection data is stored in memory, and subsequent signal processing is performed after the inspection is completed and the robot leaves the pipeline, effectively solving the communication problem.

[0048] (3) Traditional pipeline inspection robots place multiple detection coils around the perimeter and process each detection signal independently to achieve comprehensive pipeline inspection. However, this approach makes it difficult to further reduce the size of the inspection robot, limiting its potential for development towards inspecting smaller diameter pipelines. The pipeline inspection robot system provided by this invention integrates mechanical structure and eddy current detector design, innovatively inventing a rotation detection method. Specifically, the pipeline inspection robot is designed as a double-layer cylindrical structure. The outer layer (shell 9) does not rotate during movement, serving as protection and support. The inner layer (rotating inner shell 13) is coaxially fixed with the detection coil disk and driven by a motor, rotating slowly during the robot's linear movement to achieve comprehensive pipeline inspection. Under the rotation detection design of this invention, the number of detection coils is reduced to two pairs, and the number of signal paths is reduced to two.

[0049] (4) The unevenness of the inner surface of the pipe causes vibration and wear of the support wheels when the pipe inspection robot moves. Meanwhile, to ensure the support wheels do not slip during the pipe inspection process, appropriate pressure should be applied between the support wheels and the inner surface of the pipe. The support wheel design provided by this invention uses a precise combination of gears, racks, and compression springs, allowing the support wheels to radially contract to adapt to the unevenness of the pipe surface. Simultaneously, the compression spring maintains a certain pressure between the traveling wheel and the pipe surface, preventing slippage.

[0050] (5) Traditional pipeline inspection equipment is prone to sensor drift and clock inaccuracy under extreme temperatures (-40℃~85℃). Traditional temperature compensation relies on on-site multi-point calibration experiments (requiring equipment such as constant temperature chambers) or external high-precision sensors, resulting in high calibration costs and large hardware size. This invention reuses the factory calibration parameters preset by the chip manufacturer and combines them with a linear interpolation algorithm to construct a dynamic compensation model, achieving temperature drift suppression without experiments and at low cost. It avoids mechanical structure modifications caused by external sensors and maintains the robot's 120mm diameter limit size.

[0051] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, "above" or "below" a second feature may include direct contact between the first and second features, or it may include contact between the first and second features not being in direct contact but through another feature between them.

[0052] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rotary pipe inspection robot based on electromagnetic eddy current detection, characterized in that, Includes an outer shell (9), inside which is a coaxial and rotatable rotating inner shell (13), and at the front end of the outer shell (9) is a detachable front mounting seat (7); at the rear end of the outer shell (9) is a motor (15), and the shaft of the motor (15) is connected to the rear end of the rotating inner shell (13). Several supporting moving components are installed in the rear end of both the front mounting base (7) and the outer shell (9); The front mounting base (7) is provided with a detection coil disk (4) and a fixed disk (8) connected by a connecting shaft (18) at both ends. The fixed disk (8) is provided at one end of the rotating inner shell (13). The detection coil disk (4) is provided outside the front mounting base (7). The coil assembly (5) is provided outside the detection coil disk (4). The coil assembly (5) includes an excitation coil and a detection coil. The rotating inner shell (13) is provided with a phase-locked amplifier PCB board (14), a signal generator PCB board (10), a battery (11), and an STM32 development board (12). The excitation coil is electrically connected to the signal generator PCB board (10), and the detection coil is electrically connected to the phase-locked amplifier PCB board (14).

2. The rotary pipe inspection robot based on electromagnetic eddy current detection according to claim 1, characterized in that, Two mirror-symmetrical support and moving components are installed in the rear end of the front mounting base (7) and the housing (9).

3. The rotary pipe inspection robot based on electromagnetic eddy current detection according to claim 1, characterized in that, The supporting moving assembly includes a support wheel (1) with gears, a rack (2) and a compression spring (3), one end of the rack (2) abutting against the compression spring (3), and the gear in the support wheel (1) with gears meshing with the rack (2); The compression spring (3) and rack (2) are fixedly disposed in a cavity opened in the rear end of the front mounting base (7) or the housing (9), and the support wheel (1) with gear protrudes from the rear end of the front mounting base (7) or the housing (9).

4. The rotary pipe inspection robot based on electromagnetic eddy current detection according to claim 1, characterized in that, The coil assembly (5) is fixedly mounted on the detection coil disk (4) by the coil fixing member (6).

5. A rotary pipe inspection robot based on electromagnetic eddy current detection according to claim 1, characterized in that, The outer shell (9), rotating inner shell (13), front mounting base (7) and rear mounting base (16) are each composed of two parts.

6. A rotary pipe inspection robot based on electromagnetic eddy current detection according to claim 1, characterized in that, The signal generator PCB board (10) adopts the DDS method and is composed of an STM32F103C8T6 microcontroller, an AD9834 signal generator chip and a 75MHz crystal oscillator.

7. A rotary pipe inspection robot based on electromagnetic eddy current detection according to claim 1, characterized in that, The phase-locked amplifier PCB board (14) is an AD8302 chip.

8. A rotary pipe internal inspection system based on the electromagnetic eddy current detection of the robot described in claim 1, characterized in that, include: The signal transmitting module is used to transmit two sinusoidal signals of equal frequency, namely an excitation signal and a reference signal; the excitation signal is used to be emitted externally through an excitation coil for defect detection. A lock-in amplifier module is used to receive a detected signal and a reference signal, and extract the amplitude ratio and phase difference of the detected signal and the reference signal to obtain the detected defect. The detected signal is the signal returned by defect detection. The signal processing and acquisition module receives the amplitude ratio and phase difference between the detected signal and the reference signal, and calculates the defects of the sample to be tested.

9. The rotary pipe inspection system for electromagnetic eddy current detection of a robot according to claim 8, characterized in that, It also includes a detection signal preprocessing module for amplifying the detection signal; A PC or oscilloscope is used to display the detected defect information.

10. A detection method based on the detection system of claim 8, characterized in that, The signal generator PCB (10) generates two sinusoidal signals of the same frequency. One signal drives the excitation coil, and the other signal is used as a reference signal input to the phase-locked amplifier PCB (14). The signal from the detection coil is also sent to the phase-locked amplifier PCB (14), which extracts the amplitude ratio and phase difference of the two signals and outputs them as DC voltage to the STM32 development board (12) to obtain defect information.

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