Variable-diameter sprocket type pipeline defect detection robot and detection method

Abstract

The application relates to a variable-diameter Mecanum wheel type pipeline defect detection robot and a detection method, and belongs to the technical field of pipeline robots. The robot comprises a center variable-diameter module, the center variable-diameter module comprises a center support, three groups of Mecanum wheel foot end walking modules are connected to the center support, the Mecanum wheel foot end walking module comprises a walking support, and front and rear two groups of Mecanum wheels are installed on the walking support; the walking support of each group of Mecanum wheel foot end walking modules is connected with the center support through a group of first connecting rods; a sliding block is arranged in the center support in a sliding mode, one second connecting rod is arranged between the sliding block and each group of first connecting rods; a detection module is arranged at the front end of the center support, an electric control module is arranged at the rear side in the center support, and a power supply module is arranged in the center support; the problems that current pipeline robots are difficult to meet the requirements of high-precision defect detection of small-diameter pipelines are solved.

Description

Technical Field

[0001] This invention belongs to the field of pipeline robot technology, specifically relating to a variable-diameter Meyer wheel-type pipeline defect detection robot and detection method. Background Technology

[0002] Industrial pipelines are core infrastructure for energy transmission and industrial production, undertaking the transportation of media such as oil, gas, water, steam, and chemical raw materials. The total mileage of long-distance oil and gas pipelines, urban gas pipelines, and industrial pipelines in China is enormous. These pipelines operate under harsh conditions such as high pressure, high temperature, corrosion, and vibration, making them prone to defects such as internal wall cracks, corrosion pits, and weld cracks. If not inspected and repaired in a timely manner, these defects can easily lead to leaks, explosions, and other safety accidents, causing significant casualties and economic losses. Traditional manual inspection methods suffer from low efficiency, high labor intensity, insufficient inspection accuracy, and difficulty in full-circumference inspection. Furthermore, manual inspection of special pipelines carries extremely high safety risks. Existing pipeline robots, such as wheeled, tracked, and spiral robots, each have shortcomings in their structural and operational adaptability, exhibiting limitations such as small diameter range, unadjustable wall pressure, slippage, low inspection accuracy, and poor real-time performance. These deficiencies make it difficult to meet the practical engineering needs of high-precision defect inspection for small-diameter pipelines. Summary of the Invention

[0003] This invention overcomes the shortcomings of existing technologies and proposes a variable-diameter Meyer wheel-type pipeline defect detection robot and detection method; it solves the problem that current pipeline robots cannot meet the high-precision defect detection requirements of small-diameter pipelines.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution.

[0005] A variable-diameter Mecanum wheel-type pipe defect detection robot includes a central variable-diameter module, which includes a central support. Three sets of Mecanum wheel-end walking modules are connected to the central support. Each Mecanum wheel-end walking module includes a walking bracket with two sets of Mecanum wheels mounted on it. The walking bracket of each Mecanum wheel-end walking module is connected to the central support via a set of first connecting rods. A slider is slidably arranged inside the central support, and a second connecting rod is arranged between the slider and each set of first connecting rods. A detection module is arranged at the front end of the central support, an electrical control module is arranged at the rear inside the central support, and a power supply module is arranged inside the central support.

[0006] Furthermore, the central support includes three parallel connecting rods, with a common front triangular connecting plate fixedly disposed between the front ends of the three connecting rods, a common rear triangular connecting plate fixedly disposed between the rear ends of the three connecting rods, and a common middle triangular connecting plate fixedly disposed between the middle parts of the three connecting rods; the distance between the front triangular connecting plate and the middle triangular connecting plate is greater than the distance between the middle triangular connecting plate and the rear triangular connecting plate.

[0007] Furthermore, a lead screw sleeve is fixedly installed at the center of the front face of the central triangular connecting plate, and the cross-section of the lead screw sleeve is an equilateral triangle; a first connecting hole is provided at the center of the central triangular connecting plate, and the first connecting hole coincides with the through hole inside the lead screw sleeve; a lead screw motor is fixedly installed at the center of the rear face of the central triangular connecting plate, and the output shaft of the lead screw motor extends into the inside of the lead screw sleeve through the first connecting hole; a lead screw is rotatably inserted inside the lead screw sleeve, one end of the lead screw is fixedly connected to the output shaft of the lead screw motor, and the other end of the lead screw is rotatably connected to the center of the front triangular connecting plate.

[0008] Furthermore, the walking module at the foot of the wheel is provided in three sets, and the walking brackets of the three sets of walking modules correspond to the three outer sides of the lead screw sleeve respectively; a set of first connecting rods is provided between the walking bracket and the corresponding outer side of the lead screw sleeve, and each set of first connecting rods includes two parallel first connecting rods; one end of the two first connecting rods is hinged to the outer side of the lead screw sleeve, and the other end of the two first connecting rods is hinged to the walking bracket.

[0009] Furthermore, a slider is slidably sleeved on the outside of the lead screw, located at the front of the lead screw sleeve. The slider has an equilateral triangular cross-section, and a threaded seat is fixedly installed at the front opening of the slider, which is screwed onto the outside of the lead screw. A second connecting rod is rotatably installed on each of the three outer surfaces of the slider, corresponding one-to-one with three sets of first connecting rods. One end of the second connecting rod is hinged to the outer surface of the slider, and the other end is hinged to the first connecting rod in the corresponding set of first connecting rods. The slider includes a first slider body and a second slider body, both of which are sleeved on the outside of the lead screw. The first slider body is located in front of the second slider body. A spring is fixedly installed between the first and second slider bodies, and the spring is sleeved on the outside of the lead screw. The threaded seat is fixedly installed at the front opening of the first slider body, and the three second connecting rods are rotatably installed on the three outer surfaces of the second slider body.

[0010] Furthermore, the walking support includes a motor connecting plate and a first link connecting plate; the motor connecting plate is a U-shaped plate structure, including a transverse section in the middle and longitudinal sections on both sides; the first link connecting plate is fixedly installed on the outer surface of the transverse section of the motor connecting plate, and the ends of the two first links away from the central support are hinged to the first link connecting plate; a walking motor is fixedly installed on the inner side of the two longitudinal sections of the motor connecting plate, and a Mecanum wheel is fixedly installed on the output shaft of each of the two walking motors.

[0011] Furthermore, the detection module includes a detection unit and a rotation unit, wherein the rotation unit is located at the front end of the central support, and the detection unit is located at the front end of the rotation unit; the rotation unit includes a coupling cover, a joint motor frame, and a joint motor, with the coupling cover fixedly installed at the rear end of the joint motor frame and fixedly connected to the front end of the central support; a joint motor is fixedly installed at the front end of the joint motor frame; the detection unit includes a detection housing, with a control compartment fixedly installed at the rear end of the detection housing, the control compartment being fixedly installed on the output shaft of the joint motor; a patrol camera module and an ultrasonic sensor are installed at the front end of the detection housing, the patrol camera module including a servo motor and a patrol camera connected to the actuating end of the servo motor; a laser sensor and a macro camera are installed on the outer surface of the detection housing; a detection control module is also installed inside the control compartment, and the detection control module is connected to the laser sensor, the patrol camera module, and the macro camera via a USB interface.

[0012] Furthermore, the power supply module includes a battery fixing plate, which is fixedly mounted on one of the connecting rods; an end fixing plate is fixedly mounted at each end of the battery fixing plate, and both end fixing plates are fixedly sleeved on the outside of the corresponding connecting rods; an aviation battery is fixedly mounted on the outer surface of one side of the battery fixing plate, and the aviation battery is connected to all the power-consuming components of the robot; a balance plug and a power plug are fixedly mounted on each end fixing plate.

[0013] Furthermore, the electronic control module includes a control positioning frame, which is fixedly installed on the front end face of the rear triangular connecting plate. A control end cover is arranged on each of the three outer sides of the control positioning frame. The main controller and motor drive module are installed inside the control positioning frame. The library function system is compiled and runs on the main controller and the detection control module.

[0014] A pipeline defect detection method, utilizing the aforementioned variable-diameter Meyer wheel-type pipeline defect detection robot, includes the following steps:

[0015] Step 1: System initialization. The drive unit component library functions sequentially control the walking motor, servo motor, lead screw motor, articulated motor, and laser sensor. The center diameter changing mechanism returns to zero and resets. The laser sensor completes focus calibration.

[0016] Step 2: Send the robot into the pipe inlet, and the lead screw motor drives the central diameter changing mechanism to expand outward, so that the Mecanum wheel contacts the pipe wall;

[0017] Step 3: The servo motor drives the inspection camera to swing back and forth to identify the road conditions ahead, and the ultrasonic sensor detects the distance between the inner wall of the pipe and the detection module; when traveling inside a straight pipe, the motors of the three sets of Mecanum wheel foot-end walking modules are controlled to rotate at the same speed, so that the three sets of Mecanum wheels move synchronously and at a constant speed; when encountering a curved pipe, the motors of the three sets of Mecanum wheel foot-end walking modules are controlled to rotate at different speeds to achieve differential steering through the curve;

[0018] Step 4: The joint motor drives the detection housing to rotate 360° at a constant speed. The detection housing drives the laser sensor to rotate synchronously, so that the laser sensor continuously collects radial distance data of the pipe wall and stores it in segments in CSV format.

[0019] Step 5: The host computer reads multiple CSV data segments in batches, and generates a complete pipe wall model by normalizing the mean, converting the cylindrical coordinates to rectangular coordinates, and splicing the cylindrical surfaces. The radial distance deviation is calculated and the defects are initially screened by binarization, and the depth, aspect ratio, and size features of suspected defects are extracted.

[0020] Step 6: Trigger the stop command, the robot brakes, the control center's diameter-changing mechanism expands outward to increase the wall-attaching pressure, the laser sensor performs low-speed, high-density scanning, and at the same time, the macro camera acquires defect images for contour comparison and verification;

[0021] Step 7: Calculate the circumferential, axial, and radial three-dimensional coordinates of the verified defects, and label the defect type, depth, and dimensions;

[0022] Step 8: The robot continues to move forward to complete the full pipe section inspection. After the inspection is completed, it returns to the pipe outlet along the original path and generates a defect distribution map and parameter table.

[0023] The beneficial effects of this invention compared to the prior art are as follows:

[0024] (1) The composite center diameter changing structure combining active and passive diameter changing is adopted, which realizes the combination of large-range rigid adjustment and small-range dynamic compensation for different pipe diameters. The wall-adhering pre-tightening force is stable and adjustable, effectively solving the problems of small diameter changing range, unstable wall adhesion, and easy slippage of existing robots. The first and second connecting rods of the articulated arm structure decompose the radial force into two components, axial and radial, making the stress distribution of the first and second connecting rods more uniform.

[0025] (2) Each Mecanum wheel foot walking module adopts a dual walking motor direct drive Mecanum wheel design. It achieves spiral movement through the coordinated control of six walking motors. No additional rotating mechanism is required. It has a compact structure and can realize full circumferential blind spot detection of the inner wall of the pipe. It has high movement flexibility and convenient posture adjustment. The Mecanum wheel can decompose the rotational driving force output by the walking motor into two orthogonal components, axial and circumferential.

[0026] (3) Using a laser sensor as the core detection element, combined with a macro camera for visual verification, can effectively distinguish defect types, eliminate false detections, and solve the problems of low accuracy and high false detection rate of single detection technology. Using an ultrasonic sensor, the distance between the detection module and the inner wall of the pipe is detected in real time, providing feedback data for the adjustment of the central diameter changing mechanism and the focal length adjustment of the laser sensor. It can realize the adaptive adjustment of the angle of the Mecanum wheel foot walking module during the diameter changing process, ensuring that the wheel surface of the Mecanum wheel is always in perpendicular contact with the inner wall of the pipe, maximizing the contact area and improving the traction capacity.

[0027] (4) A hierarchical control architecture is adopted to separate motion control and detection processing, which improves the real-time performance and reliability of the system; it supports automatic switching between two modes: rotational scanning and stationary scanning, and can automatically adjust the detection mode according to the detection results. The drive unit component library function system is designed to independently encapsulate the drive code of all core components to form a standardized control interface. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is a schematic diagram showing the connection between the center diameter changing module, the wheel foot walking module, the electronic control module, and the power supply module.

[0031] Figure 3 This is a structural schematic diagram of the center diameter variable module;

[0032] Figure 4 This is a structural diagram of the walking module at the foot end of the wheat wheel;

[0033] Figure 5 This is a structural diagram of the power supply module;

[0034] Figure 6 This is a schematic diagram of the detection module;

[0035] Figure 7 This is a bottom view of the detection module;

[0036] Figure 8 This is the front view of the detection module;

[0037] Figure 9 This is a schematic diagram of the rotating unit.

[0038] Figure 10 This is a structural diagram of the electronic control module;

[0039] Figure 11 This is a flowchart of the defect detection method provided by the present invention;

[0040] Among them, 1 is the detection module, 2 is the walking module at the foot of the wheel, 3 is the power supply module, 4 is the electronic control module, and 5 is the center diameter changing module;

[0041] 11 is the detection unit, 12 is the rotation unit; 1101 is the acrylic protective plate, 1102 is the laser sensor, 1103 is the macro camera mounting plate, 1104 is the control compartment, 1105 is the macro camera, 1106 is the detection shell, 1107 is the laser sensor mounting plate, 1108 is the ultrasonic sensor, 1109 is the inspection camera module, 1110 is the sliding module; 1201 is the articulated motor, 1202 is the articulated motor bracket, 1203 is the coupling cover;

[0042] 201 is the first connecting rod connecting plate, 202 is the bolt, 203 is the nut, 204 is the motor connecting plate, 205 is the travel motor, and 206 is the Mecanum wheel;

[0043] 301 is the balance plug, 302 is the aviation battery, 303 is the power plug, 304 is the double-ended stud, 305 is the set screw, 306 is the battery fixing plate, 307 is the clamping plate, and 308 is the end fixing plate.

[0044] 401 is the control positioning frame, 402 is the control end cover, 403 is the main controller, and 404 is the motor drive module;

[0045] 51 is the central support, 52 is the second connecting rod, 53 is the lead screw, 54 is the lead screw sleeve, 55 is the lead screw motor, 56 is the central triangular connecting plate, 57 is the first connecting rod, 58 is the slider, and 59 is the threaded seat; 5701 is the copper bushing, and 5702 is the pin; 5801 is the first slider assembly, 5802 is the spring, and 5803 is the second slider assembly. Detailed Implementation

[0046] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0047] like Figure 1As shown in Figure 10, this invention provides a variable-diameter Mecanum wheel-type pipe defect detection robot, including a central variable-diameter module 5. The central variable-diameter module 5 includes a central support 51, and three sets of Mecanum wheel-end walking modules 2 are connected to the central support 51. Each Mecanum wheel-end walking module 2 includes a walking bracket, on which two sets of Mecanum wheels 206 are installed. The walking bracket of each set of Mecanum wheel-end walking modules 2 is connected to the central support 51 through a set of first connecting rods 57. A slider 58 is slidably arranged inside the central support 51, and a second connecting rod 52 is arranged between the slider 58 and each set of first connecting rods 57. A detection module 1 is arranged at the front end of the central support 51, an electrical control module 4 is arranged at the rear inside the central support 51, and a power supply module 3 is arranged inside the central support 51.

[0048] The central support 51 includes three parallel connecting rods arranged in an equilateral triangle, extending in the front-to-back direction. A common front triangular connecting plate is fixedly installed between the front ends of the three connecting rods, a common rear triangular connecting plate is fixedly installed between the rear ends of the three connecting rods, and a common central triangular connecting plate 56 is fixedly installed between the middle sections of the three connecting rods. The distance between the front triangular connecting plate and the central triangular connecting plate 56 is greater than the distance between the central triangular connecting plate 56 and the rear triangular connecting plate. The front, rear, and central triangular connecting plates 56 are all perpendicular to the connecting plates.

[0049] A lead screw sleeve 54 is fixedly installed at the center of the front end face of the central triangular connecting plate 56. The extension direction of the lead screw sleeve 54 is parallel to the length direction of the connecting rod, and the cross-section of the lead screw sleeve 54 is an equilateral triangle. A first connecting hole is provided at the center of the central triangular connecting plate 56, and the first connecting hole coincides with the through hole inside the lead screw sleeve 54.

[0050] The walking module 2 at the foot of the wheel is provided in three sets, and the walking brackets of the three sets of walking modules 2 correspond to the three outer sides of the lead screw sleeve 54. A set of first connecting rods 57 is provided between the walking bracket and the corresponding outer side of the lead screw sleeve 54. Each set of first connecting rods 57 includes two parallel first connecting rods 57, and the lengths of the two first connecting rods 57 are kept equal. One end of the two first connecting rods 57 is hinged to the outer side of the lead screw sleeve 54, and the other end of the two first connecting rods 57 is hinged to the walking bracket. The two first connecting rods 57, the lead screw sleeve 54, and the walking bracket form a parallelogram structure. Therefore, as the first connecting rods 57 rotate, the walking bracket moves closer to or away from the lead screw sleeve 54, and the walking bracket always remains parallel to the lead screw sleeve 54.

[0051] A lead screw motor 55 is fixedly installed at the center of the rear end face of the central triangular connecting plate 56. The output shaft of the lead screw motor 55 extends into the lead screw sleeve 54 through the first connecting hole. A lead screw 53 is rotatably inserted into the lead screw sleeve 54. One end of the lead screw 53 is fixedly connected to the output shaft of the lead screw motor 55, and the other end of the lead screw 53 is rotatably connected to the center of the front triangular connecting plate. The lead screw motor 55 is a stepper motor.

[0052] A slider 58 is slidably sleeved on the outside of the lead screw 53. The slider 58 is located in front of the lead screw sleeve 54. The slider 58 has an equilateral triangular cross-section, and its three outer surfaces correspond one-to-one with the three outer surfaces of the lead screw sleeve 54. A threaded seat 59 is fixedly installed at the front opening of the slider 58 and is screwed to the outside of the lead screw 53. A second connecting rod 52 is rotatably installed on each of the three outer surfaces of the slider 58. The three second connecting rods 52 are of equal length and correspond one-to-one with the three sets of first connecting rods 57. One end of the second connecting rod 52 is hinged to the outer surface of the slider 58, and the other end of the second connecting rod 52 is hinged to the first connecting rod 57 in the corresponding set. The connection between the second connecting rod 52 and the first connecting rod 57 is located at the end of the first connecting rod 57 away from the connecting rod sleeve. Specifically, the first link 57 and the second link 52 are hinged together by a pin 5702, and a copper bushing 5701 is fixedly nested at the hinge of the first link 57 and the second link 52, with the pin 5702 rotatably inserted into the copper bushing 5701.

[0053] The first link 57 and the second link 52 adopt a curved arm structure with a bending angle of 120°.

[0054] The slider 58 includes a first slider body 5801 and a second slider body 5803, both of which are sleeved on the outside of the lead screw 53. The first slider body 5801 is located in front of the second slider body 5803. A spring 5802 is fixedly installed between the first slider body 5801 and the second slider body 5803, and the spring 5802 is sleeved on the outside of the lead screw 53. A threaded seat 59 is fixedly installed at the front opening of the first slider body 5801. Three second connecting rods 52 are rotatably installed on the three outer surfaces of the second slider body 5803. Multiple plug-in rods are fixedly installed on the end face of the second slider body 5803 facing the first slider body 5801, and the axis of the plug-in rods is parallel to the axis of the lead screw 53. Multiple insertion slots are provided on the end face of the first slider segment 5801 facing the second slider segment 5803. Insertion rods correspond one-to-one with the insertion slots, and the end of the insertion rod furthest from the second slider segment 5803 is slidably inserted into the corresponding insertion slot. The cooperation between the insertion rods and the insertion slots ensures stable relative movement between the first slider segment 5801 and the second slider segment 5803 along the axis of the lead screw 53.

[0055] The traveling support includes a motor connecting plate 204 and a first connecting rod connecting plate 201. The motor connecting plate 204 has a U-shaped plate structure, including a transverse section in the middle and longitudinal sections on both sides. The length of the longitudinal sections on both sides is shorter than the length of the middle section, and the longitudinal sections on both sides are perpendicular to the transverse section in the middle. The length direction of the transverse section is parallel to the axis of the lead screw 53. The first connecting rod connecting plate 201 is fixedly installed on the outer surface of the transverse section of the motor connecting plate 204. The first connecting rod connecting plate 201 is fixedly connected to the motor connecting plate 204 by bolts 202 and nuts 203. The ends of the two first connecting rods 57 away from the central support 51 are hinged to the first connecting rod connecting plate 201.

[0056] A travel motor 205 is fixedly installed on the inner side of each of the two longitudinal sections of the motor connecting plate 204. The travel motor 205 is a DC geared motor, and the output shaft axis of the travel motor 205 is parallel to the axis of the lead screw 53. The output shafts of the two travel motors 205 extend to the outer side of the corresponding longitudinal plate, and a Mecanum wheel 206 is fixedly installed on the output shaft of each of the two travel motors 205. The wheel surface of the Mecanum wheel 206 has twelve small polyurethane wheels that are evenly distributed at a 45° angle.

[0057] The detection module 1 includes a detection unit 11 and a rotation unit 12, wherein the rotation unit 12 is disposed at the front end of the central support 51, and the detection unit 11 is disposed at the front end of the rotation unit 12.

[0058] The rotating unit 12 includes a coupling cover 1203, a joint motor frame 1202, and a joint motor 1201. The joint motor frame 1202 is a cylindrical structure, and its axis is set along the front-rear direction. The coupling cover 1203 is fixedly installed at the rear end of the joint motor frame 1202, and the coupling cover 1203 is fixedly connected to the front end face of the front triangular connecting plate of the central support 51. A first mounting groove is provided at the front end of the joint motor frame 1202, and the joint motor 1201 is fixedly installed inside the first mounting groove, with the output shaft of the joint motor 1201 facing forward.

[0059] The detection unit 11 includes a detection housing 1106, which is a cylindrical structure with its axis running along the front-to-back direction. A control chamber 1104 is fixedly mounted at the rear end of the detection housing 1106, and is fixedly mounted on the output shaft of the joint motor 1201. A second mounting slot is provided at the front end of the detection housing 1106. An inspection camera module 1109 is installed inside the second mounting slot. The inspection camera module 1109 includes a servo motor and an inspection camera. The servo motor is fixedly mounted inside the second mounting slot, and the inspection camera is fixedly mounted on the actuating end of the servo motor, which drives the inspection camera to swing left and right. A detachable acrylic protective plate 1101 is fixedly mounted at the outer opening of the second mounting slot. Two symmetrical ultrasonic sensors 1108 are fixedly mounted on the front face of the detection housing 1106.

[0060] A third mounting groove is provided on the lower side wall of the detection housing 1106. Both the third mounting groove and the control compartment 1104 are connected to the interior of the second mounting groove. A sliding module 1110 is fixedly installed inside the control compartment 1104. A laser sensor mounting plate 1107 is fixedly installed at the sliding end of the sliding module 1110. A laser sensor 1102 is fixedly installed on the lower end face of the laser sensor mounting plate 1107. The laser sensor 1102 is located inside the third mounting groove. The sliding module 1110 drives the laser sensor 1102 to move radially along the detection housing 1106, thereby enabling the laser sensor 1102 to extend and retract in and out of the third mounting groove, thus achieving focal length calibration of the laser sensor 1102. A macro camera mounting plate 1103 is also fixedly installed inside the third mounting groove, and a macro camera 1105 is fixedly installed on the lower end face of the macro camera mounting plate 1103.

[0061] Inside the control compartment 1104, a detection and control module is also installed. This module uses a Raspberry Pi 4B and connects to the laser sensor 1102, the inspection camera module 1109, and the macro camera 1105 via a USB interface. The Raspberry Pi 4B detection and control module is responsible for collecting data from the laser sensor 1102, the inspection camera module 1109, and the macro camera 1105. It incorporates the MATLAB Runtime environment and the OpenCV machine vision library to achieve defect identification, classification, and localization.

[0062] The power supply module 3 includes a battery fixing plate 306, which is located on one side of one of the connecting rods. The length of the battery fixing plate 306 is parallel to the axis of the connecting rod. An end fixing plate 308 is fixedly installed at each end of the battery fixing plate 306, and both end fixing plates 308 are fixedly sleeved on the outside of the corresponding connecting rod. A double-ended stud 304 is screwed onto the opposite end face of the two end fixing plates 308. The ends of the two double-ended bolts 202, away from the end fixing plates 308, are respectively screwed onto the front triangular connecting plate and the middle triangular connecting plate 56. The battery fixing plate 306 is fixedly connected to the central support 51 through the cooperation of the end fixing plates 308 and the double-ended studs 304.

[0063] An aviation battery 302 is mounted on the outer surface of one side of the battery mounting plate 306. L-shaped clamping plates 307 are mounted on both sides of the aviation battery 302, and both clamping plates 307 are fixedly connected to the battery mounting plate 306 to clamp and secure the aviation battery 302 to the battery mounting plate 306. The aviation battery 302 is connected to all the electrical components of the robot, providing power to all these components.

[0064] Two fourth mounting slots are provided on each end fixing plate 308, and a balance plug 301 and a power plug 303 are respectively installed in the two fourth mounting slots. A set screw 305 is screwed onto the side wall of each fourth mounting slot to fix the balance plug 301 and the power plug 303.

[0065] The electronic control module 4 includes a control positioning frame 401, which is fixedly mounted on the front end face of the rear triangular connecting plate. The control positioning frame 401 is a triangular prism-shaped frame structure. A control end cover 402 is arranged on each of the three outer sides of the control positioning frame 401, forming a modular encapsulation and protective structure. The control positioning frame 401 houses a main controller 403 and a motor drive module 404. The main controller 403 uses an STM32 microcontroller with a built-in PID algorithm to generate motion control commands, receive feedback signals, and perform logical operations. Three motor drive modules 404 are TB6612 motor drive modules, each located inside one of the three control end covers 402. The main controller 403 and the three drive modules are integrated onto a PCB board, which is then fixedly mounted on the control positioning frame 401. The motor drive module 404 is connected to a power drive interface 404, which converts control signals into drive current to power the travel motor 205. The main controller 403 works in conjunction with the three motor drive modules 404 to control the speed, direction, and start / stop of the six travel motors 205 and one lead screw motor 55, stabilize the speed of the Mecanum wheel 206, and receive ranging data from the ultrasonic sensor 1108 to automatically adjust the radial dimension of the center diameter changing mechanism.

[0066] The library function system includes PWM motor library functions, servo control library functions, stepper motor drive library functions, and laser sensor 1102 control library functions. All library functions are written in C language and run on STM32 microcontroller and Raspberry Pi 4B after compilation.

[0067] The specific implementation of the drive unit component library functions is as follows:

[0068] The PWM motor library functions are responsible for the initialization, speed adjustment, direction control, and global start / stop of the six travel motors 205. The initialization function, `void PWM_Motor_Init(void)`, configures the direction pins of the travel motors 205 and the PWM modules of the TIM2 and TIM3 timers, setting all control pins to push-pull output mode. The six independent speed setting functions, `void PWM_SetCompare1(uint16_t Compare)` to `void PWM_SetCompare6(uint16_t Compare)`, correspond to pins PA0~PA3 and PA6~PA7 respectively, driving the corresponding six travel motors 205. The speed setting functions determine the motor direction by inputting positive or negative speed values; positive values ​​correspond to forward rotation, and negative values ​​to reverse rotation. The global speed setting function, `void PWM_SetAllSpeed(int16_t speed)`, simultaneously configures the speed of all six travel motors 205. The global stop function, `void PWM_StopAll(void)`, sets the PWM output of all motors to 0 and initiates braking upon receiving a stop command or detecting an anomaly.

[0069] The servo control library functions are responsible for the attitude control of the inspection camera, enabling the camera to tilt left and right and perform panoramic scanning. The initialization function, `void Servo_Init(void)`, calls the underlying PWM initialization module; the angle setting function, `void Servo_SetAngle(float Angle)`, drives the inspection camera to tilt within a 45° range to the left and right.

[0070] The stepper motor driver library functions are used to control the stepper motors inside the lead screw motor 55 and the sliding module 1110. Initialization function: `void Stepper_Motor_Init(void)`, enables the GPIOB, GPIOC, and AFIO clocks, configures the pulse pin PB0 and direction pin PC15 to push-pull output mode, and resets the motor's initial state; Pulse sending function: `void Stepper_SendPulse(uint16_t pulses)`, sends pulse signals to control the motor's rotation angle and displacement distance; Direction control function: `void Stepper_SetDir(uint8_t dir)`, adjusts the motor's direction by switching level states; Speed ​​adjustment function: `void Stepper_SetSpeed(uint16_t speed)`, configures the motor speed by adjusting the pulse interval; Position locking function: `void Stepper_Lock(void)`, terminates pulse output, and the motor quickly locks its position.

[0071] The control library functions for laser sensor 1102 are adapted for laser sensor 1102. Initialization function: void Laser_Init(void), completes sensor initialization configuration and sensor attitude calibration; parameter configuration function: void Laser_SetParam(uint8_t param_id, float value), adjusts the measurement range, laser intensity, sampling period, and trigger mode.

[0072] The robot's movement principle is as follows:

[0073] When the robot is placed inside the pipe, the center diameter reducing module 5 starts, and the lead screw motor 55 starts to rotate. The lead screw motor 55 drives the lead screw 53 to rotate. Since the threaded seat 59 on the first slider split 5801 is screwed to the lead screw 53, the first slider split 5801 moves and gradually approaches the lead screw sleeve 54. The first slider split 5801 drives the second slider split 5803 to gradually approach the lead screw sleeve 54 through the spring 5802. The second slider split 5803 drives the three sets of first connecting rods 57 to rotate outward through the three second connecting rods 52, so that the three sets of Mecanum wheel end walking modules 2 gradually move away from the lead screw sleeve 54 until the Mecanum wheel 206 of the three sets of Mecanum wheel end walking modules 2 contacts the inner wall of the pipe.

[0074] Once the Mecanum wheels 206 of the three sets of Mecanum wheel-foot walking modules 2 are in stable contact with the inner wall of the pipe, the walking motors 205 are started. The six walking motors 205 drive the six Mecanum wheels 206 to move synchronously, thereby driving the robot to move in a spiral motion inside the pipe.

[0075] When traveling inside a straight tube, the six travel motors 205 rotate at the same speed, causing the six Mecanum wheels 206 to travel synchronously and at a constant speed. When encountering a curved tube, the travel motors 205 of the three sets of Mecanum wheel foot travel modules 2 are controlled to rotate at different speeds to achieve differential steering through the curve.

[0076] The rotation of the lead screw motor 55 drives the first slider segment 5801 to move axially, controlling the outward expansion or inward contraction of the Mecanum wheel foot travel module 2, thereby achieving active diameter change of the center diameter change module 5. Since a spring 5802 is installed between the first slider segment 5801 and the second slider segment 5803, when the first slider segment 5801 is fixed, a slight change in the inner diameter of the pipe wall causes a slight movement of the second slider segment 5803 via the spring 5802. This, in turn, causes a slight contraction or expansion of the Mecanum wheel foot travel module 2, ensuring stable contact between the Mecanum wheel 206 and the inner wall of the pipe, thus achieving passive diameter change of the center diameter change module 5. The center diameter change module 5 employs a combination of active and passive diameter change, enabling precise radial dimension adjustment and small-range adaptive compensation. The central variable diameter module 5 can meet the operational needs of pipelines with different diameters. In variable diameter pipelines and bends, the robot automatically adjusts the extension and retraction of the Mecanum wheel foot walking module 2 by combining active diameter change with passive compensation of spring 5802, so as to maintain stable contact between the Mecanum wheel 206 and the pipe wall.

[0077] The aforementioned robot performs defect detection in two modes: rotational scanning and stationary scanning.

[0078] Rotary scanning involves the robot moving axially in a helical motion at a constant speed in a long straight pipe section. The rotating unit 12 of the detection module 1 drives the detection housing 1106 to rotate circumferentially, and the detection housing 1106 drives the laser sensor 1102 to rotate circumferentially synchronously, thus performing helical scanning.

[0079] When the laser sensor 1102 detects a suspected defect during the stationary scanning process, the robot stops moving, and the lead screw motor 55 of the central diameter-changing mechanism rotates forward, causing the first slider split 5801 to move closer to the lead screw sleeve 54. This causes the Mecanum wheel foot end walking module 2 to move further away from the lead screw sleeve 54, increasing the contact pressure between the Mecanum wheel 206 and the inner wall of the pipe. The laser sensor 1102 rotates at low speed to scan and capture the detailed features of the defect. At the same time, a high-definition detailed image is acquired by the macro camera 1105 for verification.

[0080] like Figure 11 As shown, this invention also proposes a pipeline defect detection method, utilizing the aforementioned variable-diameter McLaren-type pipeline defect detection robot, comprising the following steps:

[0081] The first step is system initialization. The drive unit component library functions sequentially control the walking motor 205, servo motor, lead screw motor 55, stepper motor inside sliding module 1110, joint motor 1201 and laser sensor 1102. The center diameter changing mechanism returns to zero and resets. The laser sensor 1102 completes focal length calibration.

[0082] The relative position and orientation between the laser sensor 1102 and the coupling cover 1203 are calibrated, and the initial position and orientation of the coupling cover 1203 are set as the reference coordinate system. Define the 1203 coordinate system of the coupling cover as follows: The coordinate system of laser sensor 1102 is Let the rotation angle of the joint motor 1201 be... The distance that the detection unit 11 advances during operation is In coordinate system Down, The coordinates of the point are Let coordinate system Relative to coordinate system The rotation matrix and translation vector are respectively and , It can be represented as Let coordinate system Relative to coordinate system The rotation matrix and translation vector are respectively and , yes The transformation matrix between the sensor coordinate system and the coupling coordinate system is: ,but ,parameter and The distance traveled can be determined by the rotational step angle of the joint motor 1201 and the travel distance of the detection unit 11. and It can be done and Perform the calculation.

[0083] Step 2: Send the robot into the pipe inlet, and the lead screw motor 55 drives the central diameter changing mechanism to expand outward, so that the Mecanum wheel 206 contacts the pipe wall.

[0084] Third, the servo motor drives the inspection camera to swing back and forth to identify the road conditions ahead, and the ultrasonic sensor 1108 detects the distance between the inner wall of the pipe and the detection module 1. When traveling inside a straight pipe, the motors 205 of the three sets of Mecanum wheel end-walking modules 2 are controlled to rotate at the same speed, so that the three sets of Mecanum wheels 206 move synchronously and at a constant speed. When encountering a bend in the pipe, the motors 205 of the three sets of Mecanum wheel end-walking modules 2 are controlled to rotate at different speeds to achieve differential steering when cornering.

[0085] In the fourth step, the joint motor 1201 drives the detection housing 1106 to rotate 360° at a constant speed. The detection housing 1106 drives the laser sensor 1102 to rotate synchronously, so that the laser sensor 1102 continuously collects radial distance data of the pipe wall and stores it in segments in CSV format.

[0086] Step 5: The host computer reads multiple CSV data segments in batches, and generates a complete pipe wall model by mean normalization, conversion of cylindrical coordinates to rectangular coordinates, and splicing of cylindrical surfaces. The radial distance deviation is calculated and the defects are initially screened by binarization, and the depth, aspect ratio, and size features of suspected defects are extracted.

[0087] The core purpose of initial defect screening is to quickly identify suspected defect areas from the preprocessed complete data matrix, eliminating meaningless minor data fluctuations and noise, and reducing the computational load for subsequent classification and judgment. First, the radius deviation is calculated. Using the target mean as the standard radius of the pipe's inner wall, the absolute deviation of the radial distance from the standard radius is calculated for each scan point in the complete data matrix. ,in, For radius deviation; The measured radial distance of a certain scanning point collected by laser sensor 1102; The target is the mean. The magnitude of the radius deviation directly reflects the degree of deviation between the pipe inner wall position corresponding to the scan point and the standard inner wall; the larger the deviation, the more likely a defect exists. Next, the defect area is binarized, and a defect judgment threshold is set. When the radius deviation of a certain scan point... If the area exceeds a threshold, the point is identified as a suspected defect point and marked as 1; otherwise, it is identified as a normal region point and marked as 0. This generates a binary defect map, distinguishing suspected defect areas from normal areas. Finally, noise filtering is performed. Connectivity analysis is conducted on the generated binary defect map to identify all connected points marked as 1 as suspected defect areas. A minimum defect area threshold is set to filter out tiny connected regions with areas smaller than the threshold, retaining only suspected defect areas of a certain size.

[0088] The depth and geometric features of suspected defect areas are extracted. Combined with preset classification thresholds, defects are precisely categorized into several types: holes, cracks, and welds. For each suspected defect area after noise filtering, two core features are extracted as the basis for defect classification: First, depth features, including the maximum and average depth of the defect. The maximum depth is the maximum radius deviation of all scan points within the area, reflecting the severity of the defect; the average depth is the average radius deviation of all scan points within the area, helping to determine the overall deviation of the defect. Second, geometric features, including axial height, circumferential width (arc length), aspect ratio, and direction. The axial height is the dimension of the defect area in the robot's axial travel direction. The calculation formula is , where m max The maximum number of rows in the defect area; m min The smallest row in the defect area; For data accuracy; circumferential width is the angular span of the defect area along the circumference of the pipe. for , where n max The column with the largest defect area; n min The smallest column for the defect area; The angle interval is then converted to an arc length. The calculation formula is The aspect ratio is the ratio of the maximum to the minimum axial height and circumferential arc length of the defect area, reflecting the slenderness of the defect's shape. The direction is determined based on the aspect ratio. When the axial height is greater than the circumferential arc length, it is determined to be an axial defect; otherwise, it is a circumferential defect.

[0089] Based on the extracted depth and geometric features, combined with preset classification thresholds, the specific judgment rules for various types of defects are as follows: Holes: The core judgment condition is that the maximum depth of the defect is greater than the threshold and the aspect ratio is less than the threshold; Cracks: The core judgment condition is that the aspect ratio of the defect is greater than the threshold and the circumferential width is less than the threshold; Welds: The core judgment condition is that the axial height of the defect is greater than the threshold, or the circumferential arc length is greater than the threshold; Other defects: Suspected defect areas that do not meet the above three types of defect judgment conditions. These defects have irregular shapes, no significant features in depth or size, and cannot be clearly classified as holes, cracks, or welds, and are uniformly classified as other defects.

[0090] The sixth step involves triggering a stop command, causing the robot to brake, and the control center's diameter-changing mechanism to expand outwards to increase the wall-attaching pressure. The laser sensor 1102 performs a low-speed, high-density scan, while the macro camera 1105 acquires defect images for contour comparison and verification.

[0091] When the absolute deviation between the radial distance of a scanning point acquired by the laser sensor 1102 and the standard radius exceeds a set threshold, the Raspberry Pi 4B sends a stop command to the STM32 microcontroller, calling the PWM motor library function to stop all motors; simultaneously, it calls the stepper motor library function to drive the center diameter-changing mechanism to expand outward, increasing the wall-adhesive preload. Defect location and verification involves calculating the center position coordinates of each classified defect area: the center row is the average of all rows of data in the defect area, and the center column is the average of all columns of data in the defect area. The center row is then converted to the pipe axial position. Convert the center column to the circumferential angle of the pipe. By combining the target mean, the three-dimensional coordinates (circumferential angle, axial position, and radial radius) of the defect center are determined, enabling precise positioning of the defect and providing accurate location information for pipeline maintenance.

[0092] Step 7: Calculate the circumferential, axial, and radial three-dimensional coordinates of the verified defects, and label the defect type, depth, and size. If the verification is successful, record the three-dimensional coordinates, type, depth, and size of the defect; if the verification fails, it is determined to be a false detection, and the process continues.

[0093] Step 8: The robot continues to move forward to complete the full pipe section inspection. After the inspection is completed, it returns to the pipe outlet along the original path and generates a defect distribution map and parameter table.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A variable-diameter Meyer wheel-type pipe defect detection robot, characterized in that: The system includes a central variable diameter module (5), which includes a central support (51). Three sets of Mecanum wheel end walking modules (2) are connected to the central support (51). Each Mecanum wheel end walking module (2) includes a walking support, on which two sets of Mecanum wheels (206) are installed. The walking support of each set of Mecanum wheel end walking modules (2) is connected to the central support (51) through a set of first connecting rods (57). A slider (58) is slidably arranged inside the central support (51). A second connecting rod (52) is arranged between the slider (58) and each set of first connecting rods (57). A detection module (1) is arranged at the front end of the central support (51). An electric control module (4) is arranged at the rear inside the central support (51). A power supply module (3) is arranged inside the central support (51).

2. The variable-diameter Meyer wheel-type pipe defect detection robot according to claim 1, characterized in that: The central support (51) includes three parallel connecting rods. A front triangular connecting plate is fixedly installed between the front ends of the three connecting rods, a rear triangular connecting plate is fixedly installed between the rear ends of the three connecting rods, and a middle triangular connecting plate (56) is fixedly installed between the middle parts of the three connecting rods. The distance between the front triangular connecting plate and the middle triangular connecting plate (56) is greater than the distance between the middle triangular connecting plate (56) and the rear triangular connecting plate.

3. The variable-diameter Meyer wheel-type pipe defect detection robot according to claim 2, characterized in that: A lead screw sleeve (54) is fixedly installed at the center of the front end face of the central triangular connecting plate (56). The cross section of the lead screw sleeve (54) is an equilateral triangle. A first connecting hole is provided at the center of the central triangular connecting plate (56). The first connecting hole coincides with the through hole inside the lead screw sleeve (54). A lead screw motor (55) is fixedly installed at the center of the rear end face of the central triangular connecting plate (56). The output shaft of the lead screw motor (55) passes through the first connecting hole and extends into the inside of the lead screw sleeve (54). A lead screw (53) is rotatably inserted inside the lead screw sleeve (54). One end of the lead screw (53) is fixedly connected to the output shaft of the lead screw motor (55), and the other end of the lead screw (53) is rotatably connected to the center of the front triangular connecting plate.

4. The variable-diameter Meyer wheel-type pipe defect detection robot according to claim 3, characterized in that: The walking module (2) of the walking wheel is provided in three sets. The walking brackets of the three sets of walking modules (2) correspond to the three outer sides of the screw sleeve (54). A set of first connecting rods (57) is provided between the walking bracket and the corresponding outer side of the screw sleeve (54). Each set of first connecting rods (57) includes two parallel first connecting rods (57). One end of the two first connecting rods (57) is hinged to the outer side of the screw sleeve (54), and the other end of the two first connecting rods (57) is hinged to the walking bracket.

5. The variable-diameter Meyer wheel-type pipe defect detection robot according to claim 4, characterized in that: A slider (58) is slidably sleeved on the outside of the lead screw (53). The slider (58) is located on the front side of the lead screw sleeve (54). The slider (58) has an equilateral triangular cross-section. A threaded seat (59) is fixedly installed at the front opening of the slider (58). The threaded seat (59) is screwed to the outside of the lead screw (53). A second connecting rod (52) is rotatably installed on each of the three outer surfaces of the slider (58). The three second connecting rods (52) correspond one-to-one with the three sets of first connecting rods (57). One end of the second connecting rod (52) is hinged to the outer surface of the slider (58), and the other end of the second connecting rod (52) is hinged to the first connecting rod (57) in the corresponding set of first connecting rods (57). The slider (58) includes a first slider body (5801) and a second slider body (5803). Both the first slider body (5801) and the second slider body (5803) are sleeved on the outside of the lead screw (53). The first slider body (5801) is located in front of the second slider body (5803). A spring (5802) is fixedly installed between the first slider body (5801) and the second slider body (5803). The spring (5802) is sleeved on the outside of the lead screw (53). The threaded seat (59) is fixedly installed at the front opening of the first slider body (5801). Three second connecting rods (52) are rotatably installed on the three outer surfaces of the second slider body (5803).

6. The variable-diameter Meyer wheel-type pipe defect detection robot according to claim 4, characterized in that: The walking support includes a motor connecting plate (204) and a first connecting rod connecting plate (201); the motor connecting plate (204) is a U-shaped plate structure, including a transverse section in the middle and longitudinal sections on both sides; the first connecting rod connecting plate (201) is fixedly installed on the outer side of the transverse section of the motor connecting plate (204), and the ends of the two first connecting rods (57) away from the central support (51) are hinged to the first connecting rod connecting plate (201); a walking motor (205) is fixedly installed on the inner side of the two longitudinal sections of the motor connecting plate (204), and a Mecanum wheel (206) is fixedly installed on the output shaft of the two walking motors (205).

7. A variable-diameter Meyer wheel-type pipe defect detection robot according to claim 6, characterized in that: The detection module (1) includes a detection unit (11) and a rotation unit (12), wherein the rotation unit (12) is located at the front end of the central support (51), and the detection unit (11) is located at the front end of the rotation unit (12); the rotation unit (12) includes a coupling cover (1203), a joint motor frame (1202), and a joint motor (1201), wherein the coupling cover (1203) is fixedly installed at the rear end of the joint motor frame (1202), and the coupling cover (1203) is fixedly connected to the front end of the central support (51); wherein the joint motor (1201) is fixedly installed at the front end of the joint motor frame (1202), and the detection unit (11) includes a detection housing (1106), wherein the detection housing (1106) is located at the front end of the central support (51), and the detection housing (1106) is fixedly installed at the front end of the central support (51). A control compartment (1104) is fixedly installed at the rear end of the joint motor (1201). The control compartment (1104) is fixedly installed on the output shaft of the joint motor (1201). An inspection camera module (1109) and an ultrasonic sensor (1108) are installed at the front end of the detection housing (1106). The inspection camera module (1109) includes a servo motor and an inspection camera connected to the action end of the servo motor. A laser sensor (1102) and a macro camera (1105) are installed on the outer surface of the detection housing (1106). A detection control module is also installed inside the control compartment (1104). The detection control module is connected to the laser sensor (1102), the inspection camera module (1109) and the macro camera (1105) via a USB interface.

8. The variable-diameter Meyer wheel-type pipe defect detection robot according to claim 7, characterized in that: The power supply module (3) includes a battery fixing plate (306), which is fixedly mounted on one of the connecting rods. An end fixing plate (308) is fixedly mounted at each end of the battery fixing plate (306), and both end fixing plates (308) are fixedly sleeved on the outside of the corresponding connecting rod. An aviation battery (302) is fixedly mounted on the outer side of one side of the battery fixing plate (306), and the aviation battery (302) is connected to all the power-consuming components of the robot. A balance plug (301) and a power plug (303) are fixedly mounted on each end fixing plate (308).

9. A variable-diameter Meyer wheel-type pipe defect detection robot according to claim 8, characterized in that: The electronic control module (4) includes a control positioning frame (401), which is fixedly installed on the front end face of the rear triangular connecting plate. A control end cover (402) is arranged on each of the three outer sides of the control positioning frame (401). The main controller (403) and the motor drive module (404) are installed inside the control positioning frame (401). The library function system is compiled and runs on the main controller (403) and the detection control module.

10. A method for detecting pipeline defects, characterized in that, The method of using the variable-diameter Meyer wheel pipe defect detection robot according to claim 9 includes the following steps: Step 1: System initialization. The drive unit component library functions sequentially control the walking motor (205), servo motor, lead screw motor (55), joint motor (1201) and laser sensor (1102). The center diameter changing mechanism returns to zero and resets. The laser sensor (1102) completes the focal length calibration. Step 2: Send the robot into the pipe inlet, and the lead screw motor (55) drives the central diameter changing mechanism to expand outward, so that the Mecanum wheel (206) contacts the pipe wall; Step 3: The servo motor drives the inspection camera to swing back and forth to identify the road conditions ahead. The ultrasonic sensor (1108) detects the distance between the inner wall of the pipe and the detection module (1). When traveling inside the straight pipe, the walking motors (205) of the three sets of Mecanum wheel foot walking modules (2) are controlled to rotate at the same speed, so that the three sets of Mecanum wheels (206) move synchronously and at a constant speed. When encountering a curved pipe, the walking motors (205) of the three sets of Mecanum wheel foot walking modules (2) are controlled to rotate at different speeds to achieve differential steering through the curve. Step 4: The joint motor (1201) drives the detection housing (1106) to rotate 360° at a constant speed. The detection housing (1106) drives the laser sensor (1102) to rotate synchronously, so that the laser sensor (1102) continuously collects the radial distance data of the pipe wall and stores it in segments in CSV format. Step 5: The host computer reads multiple CSV data segments in batches, and generates a complete pipe wall model by normalizing the mean, converting the cylindrical coordinates to rectangular coordinates, and splicing the cylindrical surfaces. The radial distance deviation is calculated and the defects are initially screened by binarization, and the depth, aspect ratio, and size features of suspected defects are extracted. Step 6: Trigger the stop command, the robot brakes, the control center diameter changing mechanism expands outward to increase the wall pressure, the laser sensor (1102) performs low-speed high-density scanning, and at the same time the macro camera (1105) collects defect images for contour comparison verification; Step 7: Calculate the circumferential, axial, and radial three-dimensional coordinates of the verified defects, and label the defect type, depth, and dimensions; Step 8: The robot continues to move forward to complete the full pipe section inspection. After the inspection is completed, it returns to the pipe outlet along the original path and generates a defect distribution map and parameter table.

Images