An in-die ultrasonic testing apparatus, method and system

Abstract

An in-pipe ultrasonic testing device, method and system, the device comprising a probe body, a probe head, an ultrasonic transducer unit, a gimbal connection mechanism, a magnetic levitation attitude adjustment mechanism, an inertial measurement unit, a relative angle measurement unit, a front-end ranging sensor unit, a microcontroller, a space-time unified clock module, a signal processing unit and a travel driving mechanism. The gimbal connection mechanism connects the probe head and the probe body, and provides pitch and yaw degrees of freedom; the magnetic levitation attitude adjustment mechanism adjusts the attitude of the probe head through a micro electromagnetic coil array and a permanent magnet ring; the microcontroller fuses the body attitude, the head relative angle and the local geometry data of the pipe wall, calculates the wall normal direction and performs closed-loop control. The detection method comprises attitude sensing, wall normal calculation, attitude deviation calculation, magnetic levitation attitude adjustment, normal incidence detection, unified space-time reference correlation and continuous detection cycle.

Description

Technical Field

[0001] This invention relates to an ultrasonic testing device, method, and system for pipes, belonging to the field of pipe fitting testing technology. Background Technology

[0002] Non-destructive testing (NDT) of pipe fittings is widely used in petrochemical, nuclear power, heating networks, aerospace, and machinery manufacturing industries. During long-term service, pipe fittings are affected by factors such as media erosion, corrosion, stress concentration, and temperature changes, which may cause corrosion thinning, cracking, inclusion propagation, or localized damage to the inner wall. Ultrasonic testing, capable of acquiring echo information from inside the pipe wall and along its thickness, is commonly used for defect detection. Existing intra-pipe ultrasonic testing devices typically have the ultrasonic transducer fixedly mounted at the front or side of the probe. A traveling mechanism moves the probe inside the pipe, and rotation, clamping, or guiding structures are used to achieve comprehensive pipe wall inspection.

[0003] Existing typical patent literature, such as CN202111634811, discloses a non-destructive testing device and its usage method suitable for comprehensive inspection of pipe fittings, belonging to the field of non-destructive testing technology. This invention includes a moving mechanism and a testing mechanism. The moving mechanism includes a circumferential rotation unit, with the testing mechanism located on one side of the circumferential rotation unit. The circumferential rotation unit includes a motor B and a transmission shaft connected to the motor B. The testing mechanism includes a sleeve A connected to the transmission shaft. A movable rod A is fitted inside the sleeve A. A sleeve B is located on the outer peripheral sidewall of the sleeve A. The movable rod B is fitted inside the sleeve B. A sleeve C extending horizontally towards the movable rod A is located on the outer peripheral sidewall of the movable rod B. The movable rod C is fitted inside the sleeve C. Testing boxes are symmetrically arranged on the movable rod A and the movable rod C. This invention can achieve 360° rotational inspection of pipe fittings. However, during actual pipe inspection, when the probe continuously travels along the curved surface of the pipe wall, the local curvature of the pipe wall, probe posture disturbance, vibration of the traveling mechanism, and changes in contact state can cause the ultrasonic beam direction to deviate from the local normal direction of the pipe wall. This deviation can easily cause non-normal incident ultrasonic beams, resulting in fluctuations in the amplitude, phase, and arrival time of the echo signal, thus affecting the stability of defect identification. Furthermore, the lack of a unified time reference for motion control data, attitude data, and ultrasonic acquisition data leads to inaccurate correspondence between detection position, attitude state, and echo signals. Therefore, it is urgent to improve existing technologies to address the challenges of adaptively maintaining the acoustic beam incident angle and synchronously correlating attitude and echo data during continuous in-tube detection. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide an intra-tube ultrasonic testing device, method and system.

[0005] In a first aspect, the present invention provides an intra-pipe ultrasonic testing device, comprising a probe body, a probe head, an ultrasonic transducer unit, a universal joint connection mechanism, a magnetic levitation attitude adjustment mechanism, an inertial measurement unit, a relative angle measurement unit, a front-end ranging sensor unit, a microcontroller, a spatiotemporal unified clock module, a signal processing unit, and a travel drive mechanism for driving the probe body to move along the pipe wall. An ultrasonic transducer unit is mounted on the probe head; a universal joint connection mechanism connects the probe head to the probe body and provides at least pitch and yaw degrees of freedom; a magnetic levitation attitude adjustment mechanism includes a miniature electromagnetic coil array mounted on the probe body and a permanent magnet ring mounted on the universal joint connection mechanism; an inertial measurement unit is rigidly fixed to the probe body; a relative angle measurement unit is located at the universal joint connection mechanism and is used to measure the deflection angle of the probe head relative to the probe body; a front-end ranging sensor unit is located on the probe head and is used to acquire local geometric data of the tube wall in real time; a microcontroller is located on the probe body and is used to fuse the inertial measurement unit data and relative angle data to calculate the head attitude and perform closed-loop attitude control based on the wall normal direction; a spatiotemporal unified clock module is electrically connected to the microcontroller and is used to provide a unified time reference for attitude data and ultrasonic signals; a signal processing unit is used to acquire and process the echo signals received by the ultrasonic transducer unit.

[0006] Furthermore, the relative angle measurement unit is one or more of a Hall sensor array, a miniature rotary transformer, or a magnetic encoder.

[0007] Furthermore, the front-end ranging sensor unit includes a laser triangulation ranging sensor or an ultrasonic ranging array, used to acquire local curvature data of the pipe wall in real time to support dynamic calculation of the wall normal.

[0008] Furthermore, the magnetic levitation attitude adjustment mechanism adopts a differential PWM drive method and is equipped with a magnetic shielding layer to reduce electromagnetic interference to the inertial measurement unit and ultrasonic signals.

[0009] Furthermore, the overall diameter of the device is 8mm to 15mm, and the magnetic levitation attitude adjustment mechanism adopts a magnetic shielding structure and temperature monitoring, with an operating temperature range of -10℃ to 60℃.

[0010] Secondly, the present invention provides an intra-pipe ultrasonic testing method, which uses any of the above-mentioned intra-pipe ultrasonic testing devices for testing, and includes the following steps: Step S1: Attitude perception. The attitude of the probe body is obtained through the inertial measurement unit and the relative deflection angle of the head is obtained through the relative angle measurement unit. The real-time absolute attitude of the probe head is calculated by fusion. Step S2: Calculate the wall normal. Based on the probe position information and the local geometric data collected by the front-end ranging sensor, perform surface fitting to calculate the direction of the wall normal at the current contact point. Step S3: Attitude deviation calculation, compare the direction of the probe head axis with the direction of the wall normal to obtain the pitch and yaw deviation angles; Step S4: Magnetic levitation attitude adjustment. Based on the deviation angle, drive the micro electromagnetic coil array to generate directional magnetic force, and drive the probe head to make fine attitude adjustments through the universal joint. Step S5: Normal incidence detection. When the attitude deviation is less than the preset threshold and the echo phase analysis is verified, the ultrasonic transducer is triggered to emit pulses and receive echo signals. Step S6: Unify spatiotemporal reference association, and synchronize and mark attitude data, position data and ultrasonic echo signals based on a unified clock source; Step S7: Continuous detection cycle, repeating S1 to S6 under the drive of the traveling drive mechanism to realize the detection of the sound beam normal incidence during the continuous travel process inside the tube.

[0011] Furthermore, the wall normal calculation employs extended Kalman filtering to fuse probe position information, inertial measurement unit data, and ranging sensor data, and dynamically corrects the pipe wall curvature in real time.

[0012] Furthermore, the microcontroller integrates attitude fusion algorithm, surface fitting algorithm and PID control algorithm.

[0013] Furthermore, the spatiotemporal unified clock module adopts the PTP precise time protocol to achieve clock synchronization between motion control and signal acquisition.

[0014] Thirdly, the present invention provides an intra-pipe ultrasonic testing system, including any of the above-mentioned intra-pipe ultrasonic testing devices, an intra-pipe traveling mechanism, a main controller, and a data display and storage module; the main controller and the testing device are connected through a high-speed differential bus, and the PTP precise time protocol is used to realize clock synchronization between the motion control system and the signal acquisition system.

[0015] This invention offers significant advantages: it provides the probe head with a degree of freedom of attitude through a universal joint connection mechanism, achieves non-contact fine-tuning through a magnetic levitation attitude adjustment mechanism, and acquires attitude and local geometric information of the pipe wall through an inertial measurement unit, a relative angle measurement unit, and a front-end ranging sensor unit. Furthermore, it correlates attitude data, position data, and ultrasonic echo signals using a unified time reference. Compared to existing technologies, this invention can adjust the probe head attitude according to the wall normal direction during continuous movement within the pipe, ensuring a small deviation between the ultrasonic transducer unit's beam direction and the local normal direction of the pipe wall. Simultaneously, the unified time reference reduces time mismatches between motion control, attitude measurement, and signal acquisition, enabling the detection data to correspond to spatial position and attitude state, thereby improving the reliability of subsequent defect identification and location analysis. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a partial cross-sectional view of the present invention.

[0019] Figure 3 This is an exploded view outside of the present invention.

[0020] Figure 4 This is a cross-sectional view of the present invention.

[0021] Figure 5 This is a structural diagram of an ultrasonic transducer unit.

[0022] In the diagram, 1. Probe body; 2. Probe head; 3. Ultrasonic transducer unit; 31. Ceramic wafer; 32. Matching layer; 33. Backing layer; 4. Universal joint connection mechanism; 41. Fixing base; 42. Return spring; 43. Rotating pair; 44. Silicone pad; 5. Magnetic levitation attitude adjustment mechanism; 51. Miniature electromagnetic coil array; 52. Permanent magnet ring; 53. Magnetic shielding layer; 54. Temperature monitoring unit; 6. Inertial measurement unit; 7. Relative angle measurement unit; 8. Front-end ranging sensor unit; 9. Microcontroller; 10. Spatiotemporal unified clock module; 11. Signal processing unit; 14. Main controller; 15. Data display and storage module. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0025] The directional and positional terms used in this invention, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for illustration and understanding of this invention, and not for limiting the scope of protection of this invention. An inertial measurement unit is also known as an IMU; PWM stands for Pulse Width Modulation; PID stands for Proportional-Integral-Derivative; and PTP stands for Precision Time Protocol.

[0026] In existing intra-pipe ultrasonic testing devices, the probe head is prone to attitude deviation due to changes in the local curvature of the pipe wall during continuous movement, making it impossible for the ultrasonic beam to be stably pointed to the wall normal direction of the current testing point. At the same time, without a unified time reference between attitude measurement, motion control and echo acquisition, the detection data is prone to inaccurate correspondence with the actual position.

[0027] Based on this, and to improve the problems in related technologies, embodiments of this application provide an intra-pipe ultrasonic testing device, such as... Figures 1 to 5 As shown, the device includes a probe body 1, a probe head 2, an ultrasonic transducer unit 3, a universal joint connection mechanism 4, a magnetic levitation attitude adjustment mechanism 5, an inertial measurement unit 6, a relative angle measurement unit 7, a front-end ranging sensor unit 8, a microcontroller 9, a spatiotemporal unified clock module 10, a signal processing unit 11, and a travel drive mechanism that drives the probe body 1 to move along the pipe wall.

[0028] The travel drive mechanism can be installed on the rear side of the probe body 1 via a drive shaft, and the drive shaft is then connected to a drive motor or drive motor to drive the probe body 1.

[0029] The travel drive mechanism may include a drive motor, a transmission mechanism, and guide wheels. The drive motor drives the detection device to move axially along the pipe wall through the transmission mechanism, and may also cooperate with a circumferential rotation mechanism to realize a spiral detection path. As an alternative embodiment, those skilled in the art may also set the in-pipe travel mechanism to a tracked, wheeled, spiral propulsion, or traction structure, as long as it can drive the detection device to move along a predetermined path in the pipe.

[0030] The probe body 1 serves as the mounting base for the device and can be a cylindrical hollow shell structure. Inside or around its periphery are housed a microcontroller 9, a unified time-space clock module 10, a signal processing unit 11, an inertial measurement unit 6, and related wiring channels. The probe head 2 is located at the front end of the probe body 1, and the ultrasonic transducer unit 3 is mounted on the probe head 2, with its emitting surface facing the pipe wall 13 to be inspected. The ultrasonic transducer unit 3 can be a combination structure of a piezoelectric ceramic wafer 31, a matching layer 32, and a backing layer 33, emitting ultrasonic pulses and receiving echo signals reflected from the pipe wall 13 or defect interfaces. The signal processing unit 11 is electrically connected to the ultrasonic transducer unit 3 and may include a pulse excitation circuit, a preamplifier circuit, a filter circuit, and an analog-to-digital converter circuit, used to excite, receive, amplify, and digitize the echo signals.

[0031] The universal joint connection mechanism 4 connects the probe head 2 to the probe body 1, providing at least two degrees of freedom: pitch and yaw. Specifically, the universal joint connection mechanism 4 can adopt a cross-axis structure, a ball-and-socket structure, or a flexible hinge structure, allowing the probe head 2 to swing at a small angle relative to the probe body 1. The magnetic levitation attitude adjustment mechanism 5 includes a miniature electromagnetic coil array 51 disposed on the probe body 1 and a permanent magnet ring 52 disposed on the outer wall of the universal joint connection mechanism 4. The miniature electromagnetic coil array 51 is arranged circumferentially. When coils in different orientations generate magnetic fields of different directions and magnitudes according to control commands, the permanent magnet ring 52 is subjected to directional magnetic force, thereby driving the universal joint connection mechanism 4 and the probe head 2 to produce pitch or yaw attitude fine adjustments.

[0032] The universal joint connection mechanism 4 in this application adopts a ball-and-socket structure, including a fixed base 41, a return spring 42, and a rotating joint 43. The rotating joint 43 is fixedly connected to the probe head 2 by threads, and the rotating joint 43 is hinged to the fixed base 41, enabling the probe head to rotate via the magnetic levitation attitude adjustment mechanism 5. To further improve the smoothness of rotation of the rotating joint 43, a silicone pad 44 is provided between the rotating joint 43 and the fixed base 41 to help reduce friction.

[0033] An inertial measurement unit 6 is rigidly fixed to the probe body 1, with its mounting surface maintaining a fixed attitude relationship with the probe body 1 to measure the angular velocity, acceleration, or attitude change information of the probe body 1 during its movement within the pipe. A relative angle measurement unit 7 is located at the universal joint connection mechanism 4 and is used to measure the deflection angle of the probe head 2 relative to the probe body 1. After receiving the body attitude data from the inertial measurement unit 6 and the head deflection angle data from the relative angle measurement unit 7, the microcontroller 9 can calculate the real-time absolute attitude of the probe head 2. A front-end ranging sensor unit 8 is located on the probe head 2 and is used to collect local geometric data of the pipe wall in front of or around the probe head 2. The microcontroller 9 calculates the wall normal direction near the current detection point based on this local geometric data and compares the axial direction of the probe head 2 with the wall normal direction to obtain the attitude deviation. A unified time-space clock module 10 is electrically connected to the microcontroller 9 and provides a unified time reference for attitude data and ultrasonic signals, enabling the attitude, position, and echo data at the same detection moment to be correlated via timestamps.

[0034] The beneficial effects of this implementation are that the probe body 1 and probe head 2 are no longer completely fixedly connected, but instead form a controllable attitude relationship through a universal joint connection mechanism 4; the magnetic force between the micro electromagnetic coil array 51 and the permanent magnet ring 52 allows the probe head 2 to be finely adjusted non-contactly within a small space, reducing the impact of mechanical transmission gaps on the fine-tuning accuracy. The inertial measurement unit 6 measures the attitude of the probe body 1, and the relative angle measurement unit 7 measures the relative deflection of the probe head 2. The fusion of these two measurements yields the sound beam direction of the ultrasonic transducer unit 3. The front-end ranging sensor unit 8 provides local geometric information of the pipe wall 13, allowing the attitude control target to be updated according to the current pipe wall state, rather than solely based on the preset pipe diameter. Thus, during continuous travel within the pipe, the microcontroller 9 can adjust the probe head 2 according to the wall normal direction, reducing echo fluctuations caused by oblique sound beam incidence; simultaneously, a unified time reference allows the detection signal and corresponding attitude state to be stored synchronously, providing a basis for subsequent defect location and data traceability.

[0035] Optionally, in some embodiments, the relative angle measuring unit 7 is one or more of a Hall sensor array, a miniature rotary transformer, or a magnetic encoder. The Hall sensor array can be arranged circumferentially along the universal joint connection mechanism 4 and cooperate with a permanent magnet ring 52 disposed on the rotary joint 43 to calculate the angle changes in the pitch and yaw directions through changes in magnetic field strength. The miniature rotary transformer can be disposed at the rotary joint 43 to acquire rotational angle information through electromagnetic induction signals. The magnetic encoder can be used in conjunction with a ring-shaped magnetic code disk to output angle pulses or absolute angle values ​​in a non-contact manner. As an alternative embodiment, those skilled in the art can also set a photoelectric encoder, a flexible strain gauge, or a capacitive angle detection structure at the universal joint connection mechanism 4, as long as the deflection angle of the probe head 2 relative to the probe body 1 can be measured, it can be used in this invention.

[0036] The beneficial effect of this implementation is that the relative angle measurement unit 7 is directly arranged at the universal joint connection mechanism 4, which can measure the actual deflection of the probe head 2 relative to the probe body 1, rather than simply calculating the head posture based on coil current or control commands. Hall sensor arrays and magnetic encoders are compact and suitable for miniaturized installation, making them suitable for probe structures with limited space within tubes; miniature rotary transformers are suitable for maintaining stable angle signals in environments with vibration or oil contamination. Through a combination of one or more angle measurement structures, the microcontroller 9 can fuse the body posture with the relative head posture, reducing posture estimation errors caused by universal joint clearance, elastic deformation, or magnetic hysteresis. In specific implementations, a ring-shaped multi-point Hall detection structure can be used to invert the two-dimensional deflection angle of the head through multi-point magnetic field distribution.

[0037] Optionally, in some embodiments, the front-end ranging sensor unit 8 includes a laser triangulation ranging sensor or an ultrasonic ranging array, used to acquire local curvature data of the pipe wall 13 in real time to support dynamic calculation of the wall normal. The laser triangulation ranging sensor can be set at the front end or side front end of the probe head 2, with its emitted beam directed towards the pipe wall 13. The receiving end calculates the distance between the probe head 2 and the pipe wall 13 based on the position of the reflected light spot. The ultrasonic ranging array may include multiple miniature ranging transducers, with multiple ranging points distributed circumferentially or axially along the probe head 2, used to acquire local point cloud distances of the pipe wall 13. The microcontroller 9 fits a local surface based on multiple ranging points and calculates the wall normal direction of the current contact point or detection point from the surface fitting result. As an alternative embodiment, those skilled in the art can also use structured light ranging, miniature eddy current displacement sensors, or mechanical contact displacement detection structures to acquire local geometric data.

[0038] The beneficial effect of this implementation is that the front-end ranging sensor unit 8 allows the calculation of the wall normal to not rely entirely on the nominal dimensions of the pipe fitting or a preset geometric model, but to be updated in conjunction with the local topography of the current detection area. When the pipe wall 13 has ellipticity, local depressions, weld reinforcement, corrosion thinning, or changes in the curvature of the bend, multiple ranging points can reflect the actual changes in the local surface. The normal direction calculated by the microcontroller 9 is closer to the true normal at the current ultrasonic incident position. In specific implementation, more than three ranging points can be set at the front end of the probe head 2, and the local normal vector can be obtained through plane fitting or quadratic surface fitting; alternatively, ranging data can be continuously collected during travel and a short-term sliding window can be formed, and surface fitting can be performed on the point cloud within the window. This method can provide a dynamic target for attitude closed-loop control and reduce attitude control deviations caused by pipe wall geometric errors.

[0039] Optionally, in some embodiments, the magnetic levitation attitude adjustment mechanism 5 employs a differential PWM drive and is equipped with a magnetic shielding layer 53 to reduce electromagnetic interference to the inertial measurement unit 6 and the ultrasonic signal. The differential PWM drive refers to the micro-electromagnetic coils located in opposite directions being energized with opposite or different duty cycles, causing the permanent magnet ring 52 to experience a resultant force or torque with a defined direction. For example, when the probe head 2 needs to deflect in the positive pitch direction, one coil increases its duty cycle while the other coil decreases its duty cycle, creating a magnetic difference; when maintaining the attitude, each coil maintains a corresponding holding current. The magnetic shielding layer 53 can be disposed between the micro-electromagnetic coil array 51 and the inertial measurement unit 6, or disposed in a localized area around the coils, and can be made of a high-permeability material or a composite shielding structure. As an alternative embodiment, those skilled in the art can also use linear constant current drive, H-bridge current drive, or partitioned pulse drive to control the micro-electromagnetic coil array 51.

[0040] The beneficial effect of this implementation is that differential PWM drive can achieve continuous fine-tuning of pitch and yaw directions by utilizing the magnetic difference between relatively arranged coils, which is more convenient for forming adjustable attitude torque compared to single-sided on / off control. Due to the small space inside the probe, the miniature electromagnetic coil array 51 is close to the inertial measurement unit 6 and the signal processing unit 11. The alternating magnetic field and switching noise generated by the coil energization may affect attitude measurement and echo acquisition. By setting a magnetic shielding layer 53 and using differential control and filtering during drive, the impact of magnetic field leakage and high-frequency switching interference on the sensor and ultrasonic signal can be reduced. In specific implementation, the coil drive frequency can be set at a position that avoids the key frequency band of ultrasonic sampling, and an analog filter circuit can be set at the front end of the signal processing unit 11 so that attitude adjustment and ultrasonic acquisition can work together within the same probe body 1.

[0041] Optionally, in some embodiments, the overall diameter of the device is 8mm to 15mm, and the magnetic levitation attitude adjustment mechanism 5 adopts a magnetic shielding structure and temperature monitoring, with an operating temperature range of -10℃ to 60℃. The temperature monitoring unit 54 can be located near the miniature electromagnetic coil array 51 to detect the temperature of the coil area in real time; the microcontroller 9 adjusts the coil drive duty cycle, limits the maximum drive current, or pauses the attitude adjustment action according to the temperature value. The magnetic shielding structure can be connected to the inner wall of the probe body 1, or it can be made into a partial cover to cover the miniature electromagnetic coil array 51. As an alternative embodiment, those skilled in the art can also set a heat-conducting bracket, heat dissipation filling material, or a time-sharing drive strategy inside the probe body 1 to reduce the temperature rise caused by continuous coil energization.

[0042] The beneficial effect of this implementation is that the overall diameter range of 8mm to 15mm allows the device to adapt to the in-pipe inspection needs of smaller inner diameter pipes, while still retaining space for installing the ultrasonic transducer unit 3, universal joint connection mechanism 4, miniature electromagnetic coil array 51, and sensor assembly. When the magnetic levitation attitude adjustment mechanism 5 operates under miniaturized conditions, coil heating and magnetic field interference are factors that need to be controlled; the temperature monitoring unit 54 can provide real-time temperature feedback to the microcontroller 9, allowing the controller to adjust the drive strategy according to the temperature status, avoiding the impact of temperature rise on coil insulation, the magnetic performance of the permanent magnet ring 52, or the operational stability of nearby electronic components. The operating temperature range is -10℃ to 60℃, covering common industrial pipeline inspection environments. Through the combination of magnetic shielding and temperature monitoring, the device can balance attitude adjustment response and signal acquisition stability during continuous inspection.

[0043] This application also provides an intra-pipe ultrasonic testing method, which uses the aforementioned intra-pipe ultrasonic testing device for testing. The method includes S100 attitude perception, S200 wall normal calculation, S300 attitude deviation calculation, S400 magnetic levitation attitude adjustment, S500 normal incidence detection, S600 unified spatiotemporal reference association, and S700 continuous detection loop.

[0044] The S100 attitude sensing system acquires the attitude of the probe body 1 through the inertial measurement unit 6 and the relative angle measurement unit 7 acquires the relative deflection angle of the probe head 2. The microcontroller 9 then calculates the real-time absolute attitude of the probe head 2. Specifically, the inertial measurement unit 6 first obtains the attitude matrix or Euler angles of the probe body 1, then the relative angle measurement unit 7 obtains the pitch and yaw angles of the probe head 2 relative to the probe body 1, and finally, the attitude transformation yields the direction of the ultrasonic transducer unit 3's acoustic beam axis in the tube coordinate system.

[0045] The S200 wall normal calculation involves performing surface fitting to calculate the wall normal direction at the current contact point based on the probe position information and the local geometric data collected by the front-end ranging sensor unit 8. The probe position information, including axial displacement, circumferential angle, or mileage, can be provided by the travel drive mechanism, the in-tube travel mechanism, or the main controller 14. After the front-end ranging sensor unit 8 collects multiple ranging points, the microcontroller 9 establishes a local surface model and calculates the normal vector of the current detection point.

[0046] The S300 attitude deviation calculation compares the direction of the probe head axis 2 with the direction of the wall normal to obtain the pitch and yaw deviation angles. The microcontroller 9 can project the direction of the sound beam axis onto the pitch and yaw planes to calculate the pitch and yaw deviations respectively.

[0047] The S400 magnetic levitation attitude adjustment uses a micro-electromagnetic coil array 51 to generate directional magnetic force based on the deviation angle. This force is then used to fine-tune the attitude of the probe head 2 via a universal joint connection mechanism 4. During control, the microcontroller 9 calculates the driving amount of each coil based on the pitch and yaw deviations, causing the permanent magnet ring 52 to experience magnetic force or torque in the corresponding direction.

[0048] In the S500 normal incidence detection, when the attitude deviation is less than a preset threshold and the echo phase analysis verification is passed, the ultrasonic transducer unit 3 is triggered to emit pulses and receive echo signals. The echo phase analysis can be performed by judging the phase continuity of the initial interface echo or the back wall echo of the pipe to confirm that the current attitude meets the detection requirements.

[0049] The S600 unified spatiotemporal reference association synchronizes attitude data, position data, and ultrasonic echo signals based on a unified clock source. The unified spatiotemporal clock module 10 provides a unified time reference to the microcontroller 9, signal processing unit 11, and main controller 14, detecting the acquisition time, attitude angle, position value, and echo data recorded in the data packet.

[0050] S700 is a continuous detection cycle. Driven by the travel drive mechanism 12, S100 to S600 are repeated to realize the detection of the sound beam incident during continuous travel inside the tube.

[0051] The beneficial effects of this implementation method are that it combines attitude perception, local geometry perception, attitude closed-loop control, and ultrasonic trigger acquisition into a continuous loop process, enabling the probe to continuously correct the ultrasonic beam direction based on the actual pipe wall condition during its movement. Compared to methods that rely solely on mechanical wall contact or fixed-angle transducers for detection, this method can explicitly set the beam direction control target to the wall normal direction at the current detection point, and trigger ultrasonic detection after the attitude deviation meets the conditions, reducing the impact of oblique beam incidence on echo amplitude and phase. The unified spatiotemporal reference association step ensures that each set of echo data corresponds to the attitude and position at the acquisition time, reducing positional errors caused by asynchronous movement and sampling during subsequent defect localization, pipe wall unfolding diagram generation, or historical data comparison. In practice, the above loop can be executed in real time during low-speed continuous movement, or a short-term dwell detection mode can be used in complex bends or weld areas.

[0052] This invention further proposes that the wall normal calculation employs an extended Kalman filter to fuse probe position information, data from the inertial measurement unit 6, and data from the front-end ranging sensor unit 8, and dynamically corrects the curvature of the pipe wall 13 in real time. The extended Kalman filter uses probe position information as the state prediction input, the attitude change output by the inertial measurement unit 6 as the motion constraint, and the local distance output by the front-end ranging sensor unit 8 as the observation, estimating the current local surface parameters of the pipe wall through a prediction and update process. As a specific implementation, the local surface of the pipe wall near the current detection point can be represented as a quadratic surface model, with state quantities including local curvature, normal vector direction, and the distance between the probe and the wall. The ranging data is used as the observation input, and the filtering result outputs the current wall normal direction. As an alternative embodiment, those skilled in the art can also use sliding window least squares fitting, recursive least squares fitting, or particle filtering methods to update the wall normal.

[0053] The beneficial effect of this implementation is that, in the pipe detection environment, single sensor data is easily affected by vibration, local contamination, changes in the coupling medium, or pipe wall roughness. Extended Kalman filtering can combine the probe motion continuity, inertial measurement results, and local ranging results, reducing the impact of single ranging anomalies on the calculation of the wall normal. By dynamically correcting the curvature in real time, the microcontroller 9 can continuously update the attitude control target when the pipe wall is bent, has a different diameter, or experiences local deformation, avoiding deviations in the normal direction caused by using a fixed pipe diameter model. In specific implementation, a smaller curvature change weight can be used in straight pipe sections, while the ranging observation weight can be increased in curved pipe sections or areas with large ranging changes, allowing the normal estimation to adjust with actual wall changes. This method makes the attitude control target more stable and also facilitates mapping continuous detection data to the spatial position of the pipe wall.

[0054] This invention further proposes that the microcontroller 9 integrates an attitude fusion algorithm, a surface fitting algorithm, and a PID control algorithm. The attitude fusion algorithm processes the data output by the inertial measurement unit 6 and the relative angle measurement unit 7 to obtain the absolute attitude of the probe head 2; the surface fitting algorithm calculates the wall normal based on the local distance data output by the front-end ranging sensor unit 8; and the PID control algorithm calculates the driving quantity of the micro electromagnetic coil array 51 based on the pitch and yaw deviations. As a specific implementation, the microcontroller 9 can set the pitch and yaw directions as two separate control loops, and output the duty cycle adjustment amount of the corresponding coil group according to the deviation in each direction. As an alternative embodiment, those skilled in the art can also use feedforward control, model predictive control, or adaptive control algorithms instead of the PID control algorithm.

[0055] The beneficial effect of this implementation is that by integrating attitude fusion, surface fitting, and closed-loop control within the microcontroller 9, the internal data transmission links of the probe can be reduced, and the delay of the attitude control loop can be decreased. The attitude fusion algorithm provides the direction of the acoustic beam axis, the surface fitting algorithm provides the direction of the wall normal, and the PID control algorithm converts the deviation between the two into coil driving quantities, forming a complete closed-loop control link. In specific implementation, the microcontroller 9 can read sensor data at a fixed control cycle, first calculate the head attitude, then update the wall normal, and then calculate the control outputs for pitch and yaw directions, and distribute the output quantities to the corresponding micro electromagnetic coils. This structure facilitates real-time control in the confined space inside the tube, and also allows the main controller 14 to only be responsible for travel control, data management, and display and storage, thereby enabling the probe to have a certain degree of autonomous attitude adjustment capability.

[0056] This invention further proposes that the spatiotemporal unified clock module 10 adopts the PTP precise time protocol to achieve clock synchronization between motion control and signal acquisition. The main controller 14 can act as the master clock node, while the probe-end microcontroller 9, signal processing unit 11, and corresponding control units of the travel drive mechanism 12 act as slave clock nodes, calibrating the clocks of each node through the PTP synchronization mechanism. Ultrasonic emission triggering, echo sampling, attitude sampling, and position recording all generate timestamps based on the synchronized clock. As a specific implementation, the main controller 14 sends a synchronization message to the probe end via a high-speed differential bus 16. Upon receiving the message, the microcontroller 9 corrects its local counter, and the signal processing unit 11 writes a unified timestamp into the sampled data frame. As an alternative embodiment, those skilled in the art can also use hardware synchronization pulses, synchronization trigger lines, or other industrial clock synchronization mechanisms to achieve equivalent synchronization.

[0057] The signal processing unit 11 includes a high-speed ADC 6-1 and signal preprocessing circuitry. The high-speed ADC 6-1 is a 14-bit ADC with a sampling rate of 200 MSPS and a signal-to-noise ratio of 72 dB. The signal preprocessing circuitry includes a low-noise amplifier (LNA), a variable gain amplifier (VGA), and a bandpass filter.

[0058] The unified time-space clock module 10 shares the same clock source with the microcontroller 5 and the signal processing unit 6, employing a temperature-compensated crystal oscillator (TCXO) with a frequency stability of ±0.5ppm. This clock source also serves as the system time reference, providing a unified timestamp for all acquired data.

[0059] The beneficial effect of this implementation is that, during the continuous movement of the in-pipe detection device, the acquisition time of attitude, position, and echo signals is not exactly the same. If each module uses an independent clock, there may be a time offset in the attitude and position corresponding to the same defect. The PTP precise time protocol enables the main controller 14, microcontroller 9, signal processing unit 11, and motion control unit to have a unified time basis, which can associate each ultrasonic echo data with the corresponding attitude data and movement position. In specific implementation, the data packet may include a unified timestamp, axial position, circumferential position, pitch angle, yaw angle, ranging data, and echo sampling sequence. The data display and storage module 15 establishes an index according to the timestamp. This scheme facilitates subsequent motion compensation, pipe wall unfolding imaging, and defect review, and reduces data correspondence errors caused by the asynchrony between the motion control system and the signal acquisition system.

[0060] This application also provides an intra-pipe ultrasonic testing system, such as... Figure 1 As shown, the system includes the aforementioned in-pipe ultrasonic testing device, a travel drive mechanism, a main controller 14, and a data display and storage module 15. The main controller 14 is connected to the testing device via a high-speed differential bus, and uses the PTP precise time protocol to synchronize the clocks of the motion control system and the signal acquisition system. The data display and storage module 15 is connected to the main controller 14 and is used to receive, display, and store the attitude data, position data, and echo data generated during the testing process.

[0061] The beneficial effect of this implementation is that the system-level design integrates the probe-end attitude adaptive detection device, the in-pipe traveling mechanism, the main controller 14, and the data display and storage module 15, enabling attitude adjustment, travel control, and signal acquisition to operate under a unified control architecture. The high-speed differential bus has good anti-interference capabilities and is suitable for transmitting control commands and detection data in environments with long cables, metal pipes, and motor drives. After synchronizing the motion control system and signal acquisition system using the PTP precise time protocol, the main controller 14 can schedule travel speed, attitude adjustment, and ultrasonic trigger acquisition according to the same time axis. In specific implementations, the main controller 14 can control the traveling drive mechanism to travel continuously at a constant speed in straight pipe sections, while reducing the speed or increasing the sampling density in curved pipe sections, weld areas, or areas with significant distance changes. The data display and storage module 15 can generate detection records according to the pipe's axial position and circumferential angle, thereby improving the traceability of the detection results.

[0062] The overall working principle of this invention is as follows: Before testing, the intra-pipe ultrasonic testing device is placed inside the pipe to be tested, and the traveling drive mechanism drives the probe body 1 to move along the pipe wall. The inertial measurement unit 6 measures the attitude of the probe body 1 in real time, and the relative angle measurement unit 7 measures the deflection angle of the probe head 2 relative to the probe body 1 in real time. The microcontroller 9 calculates the direction of the sound beam axis of the ultrasonic transducer unit 3 based on the two measurements. The front-end ranging sensor unit 8 synchronously collects local geometric data of the pipe wall, and the microcontroller 9 calculates the direction of the wall normal at the current testing point through surface fitting. Subsequently, the microcontroller 9 calculates the pitch deviation and yaw deviation between the sound beam axis and the wall normal, and controls the micro electromagnetic coil array 51 to generate directional magnetic force. The magnetic force acts on the permanent magnet ring 52 and then drives the probe head 2 to perform attitude fine adjustment through the universal joint connection mechanism 4. When the attitude deviation meets the preset conditions and is verified by echo phase analysis, the ultrasonic transducer unit 3 emits pulses and receives echo signals. The unified time clock module 10 performs unified time stamping on attitude data, position data, and ultrasonic echo signals, and the main controller 14 and data display and storage module 15 use this to complete the recording, display, and subsequent analysis of detection data.

[0063] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

[0064] While the invention has been described with reference to several specific embodiments, it should be understood that the invention is not limited to the disclosed specific embodiments. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. An intra-pipe ultrasonic testing device, characterized in that: The device comprises: a probe body and a probe head; an ultrasonic transducer unit mounted on the probe head; a universal joint connecting mechanism connecting the probe head and the probe body, providing at least pitch and yaw degrees of freedom; a magnetic levitation attitude adjustment mechanism, including a miniature electromagnetic coil array mounted on the probe body and a permanent magnet ring mounted on the universal joint connecting mechanism; an inertial measurement unit rigidly fixed to the probe body; a relative angle measurement unit located at the universal joint connecting mechanism for measuring the deflection angle of the probe head relative to the probe body; a front-end ranging sensor unit located on the probe head for real-time acquisition of local geometric data of the pipe wall; a microcontroller located on the probe body for fusing IMU data and relative angle data to calculate the head attitude and performing closed-loop attitude control based on the wall normal direction; a unified spatiotemporal clock module electrically connected to the microcontroller for providing a unified time reference for attitude data and ultrasonic signals; a signal processing unit; and a travel drive mechanism for driving the probe body to move along the pipe wall.

2. The intra-pipe ultrasonic testing device as described in claim 1, characterized in that: The relative angle measurement unit is one or more of a Hall sensor array, a miniature rotary transformer, or a magnetic encoder.

3. The intra-pipe ultrasonic testing device as described in claim 1, characterized in that: The front-end ranging sensor unit includes a laser triangulation ranging sensor or an ultrasonic ranging array, used to acquire local curvature data of the pipe wall in real time to support dynamic calculation of the wall normal.

4. The intra-pipe ultrasonic testing device as described in claim 1, characterized in that: The magnetic levitation attitude adjustment mechanism adopts a differential PWM drive mode and is equipped with a magnetic shielding layer to reduce electromagnetic interference to the inertial measurement unit and ultrasonic signals.

5. The intra-pipe ultrasonic testing device as described in claim 1, characterized in that: The overall diameter of the device is 8-15mm. The magnetic levitation attitude adjustment mechanism adopts a magnetic shielding structure and temperature monitoring, with an operating temperature range of -10℃ to 60℃.

6. A method for intra-tube ultrasonic testing, characterized in that: The detection using the apparatus according to any one of claims 1 to 5 includes the following steps: Step S1: Attitude perception. The attitude of the probe body is obtained through the inertial measurement unit and the relative deflection angle of the head is obtained through the relative angle measurement unit. The real-time absolute attitude of the probe head is calculated by fusion. Step S2: Calculate the wall normal. Based on the probe position information and the local geometric data collected by the front-end ranging sensor, perform surface fitting to calculate the direction of the wall normal at the current contact point. Step S3: Attitude deviation calculation, compare the direction of the probe head axis with the direction of the wall normal to obtain the pitch and yaw deviation angles; Step S4: Magnetic levitation attitude adjustment. Based on the deviation angle, drive the micro electromagnetic coil array to generate directional magnetic force, and drive the probe head to make fine attitude adjustments through the universal joint. Step S5: Normal incidence detection. When the attitude deviation is less than the preset threshold and the echo phase analysis is verified, the ultrasonic transducer is triggered to emit pulses and receive echo signals. Step S6: Unify spatiotemporal reference association, and synchronize and mark attitude data, position data and ultrasonic echo signals based on a unified clock source; Step S7: Continuous detection cycle, repeating S1 to S6 under the drive of the traveling drive mechanism to realize the detection of the sound beam normal incidence during the continuous travel process inside the tube.

7. The intra-tube ultrasonic testing method as described in claim 6, characterized in that: The wall normal calculation uses extended Kalman filtering to fuse probe position information, IMU data, and ranging sensor data, and dynamically corrects the pipe wall curvature in real time.

8. The intra-tube ultrasonic testing method as described in claim 6, characterized in that: The microcontroller integrates attitude fusion algorithm, surface fitting algorithm and PID control algorithm.

9. The intra-tube ultrasonic testing method as described in claim 6, characterized in that: The spatiotemporal unified clock module adopts the PTP precise time protocol to achieve clock synchronization between motion control and signal acquisition.

10. An intra-pipe ultrasonic testing system, characterized in that, It includes the in-tube ultrasonic testing device, the in-tube traveling mechanism, the main controller, and the data display and storage module as described in any one of claims 1-5; the main controller is connected to the testing device via a high-speed differential bus, and the motion control system and the signal acquisition system are synchronized using the PTP precise time protocol.

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