A propeller-adsorbed underwater ultrasonic nondestructive testing wall-climbing robot vehicle

Abstract

The present invention discloses a submarine ultrasonic non-destructive testing wall-climbing robot vehicle adsorbed by a thruster. It includes a vehicle body, and a thruster, an ultrasonic non-destructive testing device and a motion mechanism installed on the vehicle body; the thruster includes a motor, a blade, a shell, a bracket, front and rear end covers and a control system; the ultrasonic non-destructive testing device includes a pair of TOFD probes, a camera, a waterproof lamp, a clamping mechanism and a lead screw moving scanning mechanism; the motion mechanism includes wheels and a driving mechanism; the vehicle body is used to place the wheel driving mechanism, circuits and circuit boards. The number and layout of the thrusters used in the present invention play a decisive role in the entire set of equipment, which can generate thrust to make the robot vehicle adsorbed on the submarine pipeline and perform stable circumferential motion. During the movement, the robot vehicle performs internal defect detection on the submarine pipeline through a pair of probes. The present invention has a reasonable structure, stable movement, and ultrasonic detection function, which can realize the automation of submarine pipeline operation and maintenance, and ensure the safety of employees while improving efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of underwater robots, and in particular relates to a propeller-adsorbed seabed ultrasonic non-destructive testing wall-climbing robot vehicle. Background Art

[0002] Pipeline transportation is a key means of transporting materials, widely used in numerous fields, including the national economy, national defense, and municipal livelihoods. Due to the characteristics of pipeline laying, such as aerial, underground, and submersible operations, and the varying operating conditions of high and low temperatures and pressures, pipelines often operate in harsh, variable, and complex environments. Furthermore, the materials they transport may be toxic, flammable, or explosive, and local damage can lead to global paralysis or even catastrophic consequences. Therefore, pipeline safety issues are particularly prominent. Furthermore, manual inspections alone are difficult to effectively monitor pipeline safety and address any issues that arise. Furthermore, manual inspections are inefficient, costly, and pose significant safety risks.

[0003] Furthermore, existing underwater robots used for pipeline inspection suffer from redundant mechanisms, large size, heavy weight, difficulty in control, poor stability, reliability, and low inspection efficiency. Some existing underwater robot inspections rely on visual inspection, which is difficult to detect minor defects and only provides information on the pipeline surface, failing to detect internal defects. This leads to high costs, low efficiency, low accuracy, and limited data. These systems are also susceptible to environmental influences (for example, submarine pipelines can sometimes be covered by sediment or seabed organisms, concealing areas of corrosion or damage, rendering visual inspection ineffective) and are incapable of adapting to turbid and dim environments. Some underwater robots rely on magnetic attraction for movement, but this technology presents numerous challenges. For example, the strong magnetic attraction can make it difficult for the main machine to retrieve the robot from the magnetic pipeline. Strong magnetic attraction can require a more powerful power system for wall-climbing robots to move along the pipeline surface, increasing energy consumption and system complexity. Magnetic attraction is unsuitable for pipelines with weak magnetic properties due to coatings such as anti-corrosion films, or for pipelines made of non-magnetic materials. The strong magnetic field used by magnetic attraction can interfere with the operation of sensors or other equipment (especially those sensitive to magnetic fields).

[0004] Therefore, the development of a robot vehicle with a reasonable structure, stable movement, high-precision and high-efficiency ultrasonic detection function, and the use of thrusters for adsorption can solve the above problems, realize the automation of submarine pipeline operation and maintenance, and ensure the safety of employees while improving efficiency. Summary of the Invention

[0005] To address the issues raised in the background technology, this invention integrates mechatronics technology to achieve automated ultrasonic nondestructive testing (NDT) of submarine pipelines. The invention provides a thruster-assisted, wall-climbing submarine ultrasonic NDT robot. The thrusters, located on the left and right sides of the robot, are key components of the entire system. Their number and layout play a decisive role in the overall system. They generate thrust, enabling the robot to adhere to the submarine pipeline and perform stable circumferential motion. During this motion, the robot uses a pair of TOFD probes to detect internal defects in the submarine pipeline.

[0006] The technical solution adopted in the present invention is as follows:

[0007] 1. A thruster-adsorbed underwater ultrasonic nondestructive testing wall-climbing robot

[0008] The vehicle comprises a vehicle body, a propeller, an ultrasonic non-destructive testing device and a motion mechanism installed on the vehicle body; the motion mechanism controls the vehicle body to move circumferentially around the submarine pipeline; propellers are symmetrically installed on both sides of the vehicle body for adsorbing the vehicle body to the surface of the submarine pipeline; the ultrasonic non-destructive testing device is installed on the front side of the vehicle body for detecting defects in the submarine pipeline.

[0009] The thruster includes a control system, a shell and an internal structure of the thruster. The internal structure includes an electric motor, blades, a front cover and a rear cover. The internal structure of the thruster is supported and fixed in the shell by a bracket. The front cover and the rear cover with a streamlined structure are installed at the upper and lower ends of the thruster; the multiple blades are circumferentially arranged coaxially with the motor, and the blades are propeller blades. The propeller blades of the thrusters on both sides have opposite rotation directions. The blades of the thrusters on one side are positive propellers, and the blades of the thrusters on the other side are reverse propellers, so as to offset the reverse torque generated by the two thrusters. The thrust generated by the thrusters on both sides is in the same direction, both toward the center of the pipeline; the blades are driven to rotate by the motor and generate thrust, so that the robot vehicle is adsorbed on the surface of the submarine pipeline.

[0010] The control system adopts PWM control, and controls the speed and direction of the propeller motor through an electronic speed regulator, thereby controlling the rotation speed and direction of the propeller blades, changing the thrust of the propeller, allowing the robot to adhere to the surface of the submarine pipeline and adapt to the movement of the robot at different positions around the pipeline. The thrust of the propeller is obtained by the following method: force analysis is performed on the robot's gravity, the support force and friction force on the robot by the pipeline, the buoyancy and resistance of the robot, and the thrust of the propeller, and the thrust of the propeller is calculated to obtain the thrust required for the robot at different positions on the pipeline.

[0011] The ultrasonic nondestructive testing device includes a pair of TOFD probes, a camera, a waterproof lamp, a clamping mechanism, and a screw-moving scanning mechanism. Two clamping mechanisms and a camera mounting bracket are installed at the front of the screw-moving scanning mechanism through a base plate. The camera mounting bracket is fixed in the middle of the base plate, and the two clamping mechanisms are fixed on both sides of the base plate. Each clamping mechanism is equipped with a TOFD probe, and the camera and waterproof lamp are arranged in the middle of the pair of TOFD probes through the camera mounting bracket. The pair of TOFD probes are two broadband narrow-pulse probes, one transmitting and one receiving, arranged symmetrically relative to the centerline of the weld. The longitudinal position and pitch angle of the TOFD probes are adjusted by the clamping mechanism, and the lateral position and pitch angle of the TOFD probes are adjusted by the screw-moving scanning mechanism, so that the submarine pipeline weld is located on the symmetrical centerline of the two probes and the two probes are closely attached to the submarine pipeline surface.

[0012] The clamping mechanism includes an angle adjustment plate, a rotating guide rail, a slider, a mounting seat, a bolt II, a U-shaped block, a probe base, and a fixed seat; angle adjustment plates are fixed on both sides of the fixed seat, and the bottom end is connected to the rotating guide rail by a hinge; an arc groove is provided on the angle adjustment plate, and two bolts I respectively pass through the arc grooves of the angle adjustment plates on both sides and extend into the bolt holes set on both sides of the rotating guide rail; a vertical slide groove is provided on the rotating guide rail, and a slider sliding along the vertical slide groove is installed on the back of the mounting seat, and a U-shaped block is connected to the front of the mounting seat by bolt II, and the U-shaped block is hingedly connected to the probe base, and the probe base is used to install the TOFD probe; the rotation between the rotating guide rail and the angle adjustment plate is limited by tightening bolt I.

[0013] The two sides of the slider are connected to the two sides of the rotating guide rail through two springs, and a vertical spring is provided between the U-shaped block and the mounting seat to provide vertical buffering elastic force for the U-shaped block.

[0014] The pitch angle of the probe is adjusted by sliding the rotating guide rail along the angle adjustment plate, rotating the U-shaped block around bolt II, and rotating the probe base hinged to the U-shaped block; the longitudinal position of the probe is adjusted by sliding the mounting base along the vertical slide groove of the rotating guide rail.

[0015] The screw-moving scanning mechanism includes a scanning mounting base, an integrated servo drive motor, a driving wheel, a driven wheel, a reciprocating screw, a screw nut, a scanning connection angle plate, a scanning connection base plate, and a graphite copper sleeve bearing; the output shaft of the integrated servo drive motor is connected to the driving wheel, the reciprocating screw is equipped with a screw nut, one end of the reciprocating screw is connected to the driven wheel, and the driven wheel and the driving wheel are meshed and driven by another cylindrical gear; the screw nut is fixed to the base plate for mounting the clamping mechanism and the camera mounting base;

[0016] The reciprocating screw is connected at both ends to the scanning connection base plates on either side of the scanning mount via scanning connection angle plates. The side of the scanning connection base plate features an arcuate groove, along which bolts III slide. The top surface of the scanning connection angle plate features an arcuate groove, through which a fixing bolt passes. The scanning connection angle plate and the scanning connection base plate are hingedly connected via graphite copper bearings, and rotation between the two plates can be limited by tightening the fixing bolts. The scanning connection angle plate rotates around the scanning connection base plate to adjust the pitch angle of the base plate on the screw nut, thereby changing the pitch angle of the two TOFD probes. The reciprocating screw automatically returns after reaching its travel limit to prevent mechanical jamming and motor damage.

[0017] The vehicle body is used to place the wheel drive mechanism, circuit and circuit board, and the wheel drive mechanism is isolated from the circuit and circuit board by a shielding cover; the wires of the two TOFD probes, camera, waterproof light and external power supply are connected to the circuit board inside the vehicle body through the metal waterproof connector at the rear end of the vehicle body, and the wires of the two thrusters are connected to the circuit board inside the vehicle body through the two hollow waterproof sealing screws on the top of the vehicle body. The two hollow waterproof sealing screws are respectively installed in the two raised through holes opened on the top of the vehicle body.

[0018] The vehicle body is designed with grooves for installing sealing rings to ensure sealing performance and prevent internal motors, circuits, and circuit boards from being damaged by water. The seals between the screw moving scanning mechanism, the axle end cover, the upper cover plate, the connector cover plate and the lower shell of the vehicle are made of nitrile rubber sealing rings, and the dynamic seal at the wheel axle uses a skeleton oil seal sealing ring.

[0019] The motion mechanism includes four wheels and two sets of wheel drive mechanisms. The four wheels are symmetrically distributed on the left and right sides of the vehicle body. The two sets of wheel drive mechanisms are fixed inside the vehicle body and are used to drive the wheels on both sides of the vehicle body respectively; the wheel drive mechanism includes a drive motor, a power gear, a gear, a helical gear I, a helical gear II, a helical gear III, a helical gear IV and a cross bar. The helical gear III and the helical gear IV are coaxially connected to the two wheels on the same side respectively. The cross bar is fixed with a gear, a helical gear I and a helical gear II. The helical gear I and the helical gear II are meshed with the helical gear III and the helical gear IV respectively. The output shaft of the drive motor is connected to the power gear, and the power gear is meshed with the gear on the cross bar.

[0020] The driving motor in the wheel drive mechanism drives the power gear to rotate, thereby driving the gear and the helical gears I and II located on the same crossbar as the gear to rotate, and then transmits the power to rotate the helical gears III and IV, and finally drives the two wheels on the same side to rotate.

[0021] 2. Subsea Ultrasonic Nondestructive Testing Method of the Wall-Climbing Robot

[0022] First, according to the outer diameter of the pipe to be inspected, the angle plate of the clamping mechanism and the screw-moving scanning mechanism are manually adjusted to make the TOFD probe slightly overfit the pipe wall, completing the coarse adjustment. When the robot vehicle is adsorbed on the pipe wall through the thruster, the clamping mechanism is supported by the pipe wall, causing the probe base hinged on the U-shaped block to rotate. At the same time, the four springs are deformed and provide tension and thrust, thereby driving the U-shaped block to rotate around bolt II, and the mounting seat fixed to the slider to move along the vertical slide of the rotating guide rail until the spring force is balanced and stops moving, completing the fine adjustment of the position and angle of the two TOFD probes, so that the probes are closely fitted to the curved surface of the pipe wall. The elastic force of the spring on each component of the clamping mechanism ensures that the bottom surface of the probe base always remains closely fitted to the pipe wall during the movement of the robot vehicle.

[0023] The robot is then controlled by a motion mechanism to move around the surface of the submarine pipeline. Simultaneously, the control system controls the thrust of the propeller, allowing the robot to adhere to the surface of the submarine pipeline during movement. By controlling the thrust of the propeller, the robot can be adapted to different positions around the pipeline, as well as to fit and detach from the submarine pipeline, ultimately achieving stable circumferential motion of the robot along the submarine pipeline.

[0024] During the movement, the TOFD probe is used to perform real-time inspection of the submarine pipeline. The transmitting probe in the TOFD probe generates an unfocused longitudinal wave beam that is incident on the inspected workpiece at a certain angle. Part of the beam (through wave) propagates along the near-surface and is received by the receiving probe in the TOFD probe. The other part of the beam is reflected by the bottom surface or diffracted by the defect and is received by the receiving probe. Finally, an A-scan signal is formed. The phase and amplitude of the signal are then converted into a 256-level grayscale image to obtain a TOFD-D inspection image for defect identification. The number, location, and size of the defects are determined by analyzing the diffraction signals at the upper and lower endpoints of the defects and their propagation time difference, thereby realizing ultrasonic non-destructive internal defect detection of submarine pipelines.

[0025] During the inspection process, the camera performs target recognition with the assistance of waterproof lights to capture visual information of the welds on the submarine pipeline.

[0026] During the inspection process, the weld is monitored in real time to see if it is located on the symmetrical center line of the two TOFD probes. When the robot moves and the weld deviates from the symmetrical center line of the two TOFD probes, after receiving information feedback from the camera, the staff controls the screw to move the scanning mechanism to adjust the lateral position of the two TOFD probes in real time so that the weld is re-located on the symmetrical center line of the two TOFD probes.

[0027] The beneficial effects of the present invention are:

[0028] The device, which utilizes thruster adsorption and TOFD probe detection, boasts a rational structure, stable motion, and high-precision, high-efficiency ultrasonic testing capabilities. The innovative use and rational layout of the thruster and TOFD probe enable stable circular motion around submarine pipelines, reliable ultrasonic nondestructive testing, and easy control.

[0029] The camera in the device of the present invention can provide visual information to locate and evaluate the area to be inspected, and detect whether the weld is located on the symmetrical center line of the two TOFD probes. The waterproof lamp can provide sufficient lighting to ensure that the camera can accurately identify the target and capture clear images, ensuring the accuracy and reliability of the inspection work. The clamping mechanism and the screw movement scanning mechanism can adjust the probes to the appropriate position and angle, so that the dual probes fit tightly on the surface of the submarine pipeline and the weld is located on the symmetrical center line of the two probes. The wheels serve as the moving parts of the robot vehicle, and they drive the robot vehicle on the surface of the submarine pipeline by rotation. The tires with asymmetric patterns can improve the movement stability of the robot vehicle and reduce noise. In addition, the wheel drive mechanism is driven by an electric motor, and the output torque and speed are increased by using helical gear transmission.

[0030] The present invention adopts TOFD probe to detect submarine pipelines, can store detection data in digital form, can carry out multi-directional analysis, and can perform three-dimensional restoration of detected defects. It has the advantages of being light and efficient, having strong penetration, high sensitivity, high detection rate, good real-time performance, good accuracy, good repeatability, short detection time, and large detection depth. It solves the problems that underwater robots based on visual detection are limited by visibility, cannot adapt to turbid and dim seabed environments, have high cost, low efficiency, low accuracy, limited data, and are easily affected by the environment.

[0031] No matter how harsh, changeable and complex the environment is, and no matter whether the transported materials may be toxic, flammable or explosive, the thruster-adsorbed submarine ultrasonic non-destructive testing wall-climbing robot can realize the intelligent and automated operation and maintenance of submarine pipelines, and ensure the safety of employees while improving efficiency, avoiding the problems of low efficiency, high cost, low accuracy, great safety hazards, easy omission of damage and limited detection range of manual inspections. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the submarine ultrasonic non-destructive testing wall-climbing robot vehicle with thrusters attached; Figure 1 (a) and Figure 1 (b) in the figure is a schematic diagram of two different angles.

[0033] Figure 2 Schematic diagram of the propeller housing of the robotic vehicle.

[0034] Figure 3 Schematic diagram of the robot's propeller motor, blades, bracket, front and rear end covers.

[0035] Figure 4 Schematic diagram of the ultrasonic non-destructive testing device for the robotic vehicle.

[0036] Figure 5 This is a schematic diagram of the screw-moving scanning mechanism of the robot vehicle. Figure 5 (a) and Figure 5 (b) in the figure is a schematic diagram of two different angles.

[0037] Figure 6 This is a schematic diagram of the motion mechanism of the robot car. Figure 6 (a) and Figure 6 (b) in the figure is a schematic diagram of two different angles.

[0038] Figure 7 A schematic diagram of the contents of the robot vehicle's body.

[0039] Figure 8 This is a schematic diagram of the body of the robot car. Figure 8 (a) and Figure 8 (b) in the figure is a schematic diagram of two different angles.

[0040] Figure 9 Schematic diagram of the application scenario of the robot car.

[0041] Figure 10 This is a schematic diagram of the clamping mechanism of the robot vehicle. Figure 10 (a) Figure 10 (b) and Figure 10 (c) in the figure shows schematic diagrams at three different angles.

[0042] In the figure: 1. Motor, 2. Blade, 3. Housing, 4. Bracket, 5. Front cover, 6. Rear cover, 7. TOFD probe, 8. Camera, 9. Waterproof lamp, 10. Clamping mechanism, 11. Screw moving scanning mechanism, 12. Wheel drive mechanism, 13. Wheel, 14. Shield, 15. Upper cover, 16. Connector cover, 17. Lower housing; 10-1. Angle adjustment plate, 10-2. Rotating guide rail, 10-3. Slider, 10-4. Mounting seat, 10-5. Bolt II, 10-6. U-shaped block, 1 0-7. Probe base, 10-8. Fixed seat; 11-1. Integrated servo drive motor, 11-2. Driving pulley, 11-3. Driven pulley, 11-4. Reciprocating screw, 11-5. Screw nut, 11-6. Scan connection angle plate, 11-7. Scan connection base plate, 11-8. Graphite copper sleeve bearing; 12-1. Drive motor, 12-2. Power gear, 12-3. Gear, 12-4. Helical gear I, 12-5. Helical gear II, 12-6. Helical gear III, 12-7. Helical gear IV, 12-8. Crossbar DETAILED DESCRIPTION

[0043] The present invention will be further described and illustrated below in conjunction with specific embodiments and accompanying drawings. The embodiments described are only part of the embodiments of the present disclosure, not all of them. The technical features of each embodiment of the present invention may be combined accordingly, provided that there is no conflict between them.

[0044] like Figure 1 As shown, the present invention provides a submarine ultrasonic non-destructive testing wall-climbing robot vehicle with a propeller adsorption having stable movement and reliable detection, which includes four parts: a propeller, an ultrasonic non-destructive testing device, a motion mechanism and a vehicle body.

[0045] like Figure 2 and Figure 3 As shown, the thruster includes a motor 1, blades 2, a housing 3, a bracket 4, a front cover 5, a rear cover 6, and a control system. The main function of the thruster is to provide the robot with thrust to keep it in contact with the pipeline wall while it performs circular motion and inspection operations. The number and distribution of thrusters will affect the complexity of the robot's forces, the stability of its motion, and the difficulty of its motion control. To prevent the robot from shifting or tipping over due to uneven forces, resulting in an inability to stably move circumferentially around the submarine pipeline, and to avoid overly complex control, two thrusters are selected to maintain the robot's stable circumferential motion in contact with the submarine pipeline surface, taking into account the overall gravity of the robot, the thrust provided by the thrusters, the buoyancy and resistance after entering the sea, the support and friction of the pipeline on the robot, and the design of the mechanical positions around the robot. In order to ensure that the robot is subjected to balanced forces during movement and to offset the reverse torque generated by the two thrusters, the thrusters are symmetrically mounted on the left and right sides of the vehicle body, and the propellers of the two thrusters rotate in opposite directions, with blade 2 on one side being a forward propeller and blade 2 on the other side being a reverse propeller. The thrust generated by the thrusters is in the same direction, both toward the center of the pipe.

[0046] The propeller blades 2 are similar to the propellers of a ship, generating propulsion through rotation, allowing the robot to be adsorbed on the surface of the submarine pipeline. The rotation of the blades 2 is divided into forward and reverse rotation. Considering that the thrust is large when forward rotation is used, it is easy to achieve stable wall-adhering movement and accurate detection of the robot, so forward rotation is adopted and it is manufactured by 3D printing using plastic materials.

[0047] The motor 1 of the propeller is responsible for providing power and transmitting the power to the propeller blades 2 to rotate, thereby driving the propeller to operate. A corrosion-resistant and long-life underwater motor is used with a rated voltage of 24V.

[0048] The shell 3, bracket 4, front cover 5, and rear cover 6 play an important role in the structure of the propeller. The shell 3 is the external structure of the propeller, mainly providing protection and support. It can accommodate the internal propeller components and can withstand harsh environments, such as high pressure, to ensure the normal operation of the propeller. The bracket 4 is the internal structure of the propeller, used to support and fix the various components of the propeller. It has sufficient strength and rigidity to withstand the thrust and vibration generated by the propeller, ensure that the propeller remains stable during operation, and prevent the various components from being misaligned or damaged. In addition, due to the large resistance of water, the bracket 4 is designed to be streamlined to reduce water resistance and improve propulsion efficiency. The front cover 5 and rear cover 6 are located at both ends of the propeller and are also designed to be streamlined to reduce water resistance and improve propulsion efficiency. The shell 3, bracket 4, front cover 5, and rear cover 6 are manufactured by 3D printing using plastic materials.

[0049] The control system uses PWM control, controlling the speed and direction of the motor 1 through an electronic speed regulator. This controls the rotational speed and direction of the propeller blades 2, thereby varying the thrust of the propeller. This allows the submarine ultrasonic non-destructive testing wall-climbing robot to firmly adhere to the surface of the submarine pipeline, adapting to the movement of the robot at different locations around the pipeline under different stress conditions. It also allows for easy attachment and detachment of the submarine ultrasonic non-destructive testing wall-climbing robot from the submarine pipeline, ultimately achieving stable circumferential motion of the wheeled robot along the submarine pipeline. By analyzing the robot's gravity, the support and friction forces exerted by the pipeline on the robot, the buoyancy and resistance exerted on the robot, and the thrust of the propeller, and calculating the thrust required for the robot at different locations on the pipeline, the motor speed can be set to provide the appropriate thrust from the propeller. When the motor stops, the robot can detach from the pipeline.

[0050] like Figure 4 As shown, the ultrasonic non-destructive testing device includes a pair of TOFD probes 7, a camera 8, a waterproof lamp 9, a clamping mechanism 10 and a screw moving scanning mechanism 11, which are assembled in front of the vehicle body.

[0051] The TOFD probe 7 is a broadband, narrow-pulse probe, one transmitting and one receiving, symmetrically arranged relative to the weld centerline. The transmitting probe generates an unfocused longitudinal wave beam, which is incident on the inspected workpiece at a certain angle. Part of the beam (through wave) propagates along the near-surface and is received by the receiving probe, while another part of the beam is reflected from the bottom surface or diffracted by the defect and is received by the receiving probe. Finally, an A-scan signal is formed. The phase and amplitude of the signal are then converted into a 256-level grayscale image to obtain a TOFD-D detection image that can be used to identify defects. Therefore, the robot can analyze and determine the number, location, and size of defects based on the diffraction signals at the upper and lower endpoints of the defect and their propagation time difference, thereby realizing ultrasonic non-destructive internal defect detection of submarine pipelines and improving the safety and reliability of the pipelines.

[0052] The camera 8 is used for target identification, capturing the appearance, shape, and detailed information of the target to be inspected (e.g., a weld), providing visual information to help personnel locate and evaluate the inspection area and detect whether the weld is located on the symmetrical centerline of the two TOFD probes 7. If the weld deviates from the symmetrical centerline of the two TOFD probes 7 during the robot's movement, the personnel can use the information feedback from the camera 8 to control the screw-moving scanning mechanism 11 in real time to adjust the lateral position of the two TOFD probes 7 so that the weld is relocated to the symmetrical centerline of the two TOFD probes 7. The robot's operating environment is typically deep sea, with poor lighting conditions, making it impossible to rely directly on natural light for observation and inspection. Therefore, the waterproof light 9 is used to provide sufficient illumination to ensure that the camera 8 can obtain clear images. The waterproof light 9 can operate in underwater environments and produce light of sufficient brightness, allowing the camera 8 to accurately identify the target and capture clear images, ensuring the accuracy and reliability of the inspection work.

[0053] The clamping mechanism 10 and the screw-moving scanning mechanism 11 are used to adjust the TOFD probe 7 to a suitable position and angle (so that the dual probes fit tightly against the surface of the submarine pipeline and the weld is located on the symmetrical center line of the two probes). The clamping mechanism 10 can adjust the longitudinal position and pitch angle of the TOFD probe 7, and the screw-moving scanning mechanism 11 can adjust the lateral position and pitch angle of the TOFD probe 7. They are driven by a motor and a reciprocating screw.

[0054] like Figure 10As shown, angle adjustment plates 10-1 are fixed on both sides of the fixed seat 10-8 in the clamping mechanism 10, and a rotating guide rail 10-2 is hingedly connected to the bottom end. The rotating guide rail 10-2 is fixed to the angle adjustment plate 10-1 by bolt I, and the rotation of the two is restricted by tightening the bolt I. The pitch angle of the probe is changed by adjusting the relative position of the rotating guide rail 10-2 and the angle adjustment plate 10-1. First, the clamping mechanism 10 and the angle plate of the screw-driven scanning mechanism 11 are roughly manually adjusted based on the outer diameter of the pipe to be inspected, ensuring that the TOFD probe 7 is properly aligned with the pipe wall, completing coarse adjustment. When the robotic vehicle is adsorbed onto the pipe wall via the thruster, the clamping mechanism 10 receives support from the pipe wall, forcing the probe base 10-7, hinged to the U-shaped block 10-6, to rotate. Simultaneously, the four springs deform and provide tension and thrust, driving the U-shaped block 10-6 to rotate around bolt II 10-5 and the mounting base 10-4, fixed to the slider 10-3, along the vertical guideway of the rotating guide rail 10-2. Once the forces are balanced, the four springs maintain the position of these moving components, completing fine adjustment of the position and angle of the two TOFD probes 7. Therefore, the use of springs and hinges ensures that the two TOFD probes 7 remain tightly aligned with the pipe surface during the robotic vehicle's movement, allowing the probes' longitudinal position and pitch angle to be adjusted. In addition, the elastic force of the spring on each component in the clamping mechanism 10 enables the robot to still keep the bottom surface of the probe base 10-7 in close contact with the pipe wall when encountering an uneven pipe surface.

[0055] like Figure 5 As shown, the integrated servo drive motor 11-1 in the screw-type scanning mechanism 11 drives the driving wheel 11-2, thereby driving the cylindrical gear and the driven wheel 11-3. The driven wheel 11-3 in turn drives the reciprocating screw 11-4 fixed to it. The reciprocating screw 11-4 drives the screw nut 11-5 to move laterally. The TOFD probe 7 is assembled in the clamping mechanism 10, and the camera 8, waterproof light 9, and the two clamping mechanisms 10 are mounted together on a base plate, which is assembled on the screw nut 11-5. Therefore, the screw-type scanning mechanism 11 can adjust the lateral position of the probe. The scanning connection angle plate 11-6 in the screw-type scanning mechanism 11 is connected to the scanning connection base plate 11-7 by bolt III, a fixing bolt, and a graphite copper sleeve bearing 11-8. The rotation of both is restricted by tightening the fixing bolt. In addition, the reciprocating screw 11-4 will automatically return after reaching the limit of transmission stroke to avoid mechanical jamming and motor damage. At the same time, the active stroke of the screw scanning mechanism 11 is 150mm, and the manually adjustable pitch angle is 0-65°, so that the dual TOFD probe 7 can fit the pipeline.

[0056] like Figure 6 and Figure 7As shown, the motion mechanism includes two sets of wheel drive mechanisms 12 and four wheels 13. The four wheels 13 are symmetrically distributed on the left and right sides of the robot, mounted on the wheel drive mechanisms 12, and equipped with tires. The two sets of wheel drive mechanisms 12 are fixed inside the robot body and isolated from the internal circuits and circuit boards by a shielding cover 14. The wheels 13 serve as the robot's moving components, propelling the robot across the surface of the submarine pipeline through rotation. They also serve as support points on the robot's bottom, providing stable support. Furthermore, the contact area of ​​the wheels 13 distributes the robot's weight and maintains balance, thereby maintaining stability on the uneven surface of the submarine pipeline. The tires with an asymmetric tread pattern improve the robot's stability and reduce noise. The driving motor 12-1 in the wheel driving mechanism 12 drives the power gear 12-2 to rotate, thereby driving the gear 12-3 and the helical gear I 12-4 and the helical gear II 12-5 located on the same crossbar 12-8 as the gear 12-3 to rotate, and then transmits the power to rotate the helical gear III 12-6 and the helical gear IV 12-7, and finally drives the two wheels 13 on the same side to rotate.

[0057] like Figure 8 As shown, the vehicle body houses the wheel drive mechanism 12, circuits, and circuit boards, and is connected to the wheels 13, propellers, and ultrasonic nondestructive testing equipment. Its upper cover 15 features two through-holes for connecting the propeller wires to the circuit board inside the vehicle body via M8 hollow waterproof sealing screws. The rear connector cover 16 has five holes for mounting metal waterproof connectors, allowing wires from the two TOFD probes 7, camera 8, waterproof light 9, and external power supply to pass through and connect to the circuit board. The vehicle body is designed with grooves for installing sealing rings to ensure a tight seal and prevent water damage to the internal motor, circuits, and circuit boards. Nitrile rubber sealing rings are used to seal the lead screw scanning mechanism 11, the axle end cap, the upper cover 15, the connector cover 16, and the lower vehicle body 17. A skeleton oil seal is used for the dynamic seal at the wheel axle.

[0058] In specific implementation, the robot vehicle can be applied to submarine pipelines with a diameter greater than or equal to 400 mm. Example 1:

[0059] like Figure 9 As shown, the entire thruster-attached submarine ultrasonic non-destructive testing wall-climbing robot vehicle is connected to a 24V power supply. Under the control of a 12V circuit board, two thrusters symmetrically distributed on the left and right sides of the vehicle body generate thrust so that it is firmly attached to the outer surface of the submarine pipeline and performs stable circular motion as the wheels 13 rotate at a uniform speed.

[0060] During the movement, the thrust of the propeller can be appropriately adjusted according to the force conditions of the robot vehicle at different positions on the outer surface of the submarine pipeline, that is, the speed of the propeller's motor 1 can be adjusted, so that the robot vehicle will not fit too closely or slightly separate from the outer surface of the submarine pipeline in certain movement sections, so as to achieve stable movement and accurate detection of the robot vehicle and save energy.

[0061] During its movement, the robot performs testing and inspection using two broadband, narrow-pulse TOFD probes 7, one transmitting and one receiving, symmetrically arranged relative to the weld centerline. The transmitting probe generates an unfocused longitudinal wave beam, which is incident on the inspected workpiece at a certain angle. Part of the beam (through wave) propagates along the near-surface and is received by the receiving probe, while another part of the beam is reflected from the bottom surface or diffracted by the defect and is received by the receiving probe. Finally, an A-scan signal is formed. The phase and amplitude of the signal are then converted into a 256-level grayscale image to obtain a TOFD-D detection image that can be used to identify defects. Therefore, the robot can analyze and determine the number, location, and size of defects through the diffraction signals at the upper and lower endpoints of the defect and their propagation time difference, thereby realizing ultrasonic non-destructive internal defect detection of submarine pipelines, such as weld inspection.

[0062] During the inspection process, with the assistance of the waterproof lamp 9, the camera 8 can perform target recognition, capture the appearance, shape and detailed information of the target to be inspected (such as a weld), and provide visual information to help staff locate and evaluate the area to be inspected.

[0063] In addition, the clamping mechanism 10 can adjust the longitudinal position and pitch angle of the TOFD probe 7, and the screw-moving scanning mechanism 11 can adjust the lateral position and pitch angle of the TOFD probe 7, so that the dual probes fit tightly to the surface of the submarine pipeline and the weld is located on the symmetrical center line of the two probes. Example 2:

[0064] Based on Example 1, during the motion detection process, the thrust of the robot's propeller, the rotation speed of the wheel 13, the clamping mechanism 10, and the screw-moving scanning mechanism 11 can be adjusted according to task requirements and detection efficiency requirements (such as achieving a single scanning detection time of no more than 5 minutes, achieving a detection resolution better than 2 mm, and achieving a detection accuracy of 100%) to change the movement speed and stability of the trolley and the degree of contact between the TOFD probe 7 and the outer surface of the submarine pipeline. Example 3:

[0065] Based on Example 1, if the mother machine (the carrier of the submarine ultrasonic non-destructive testing wall-climbing robot vehicle adsorbed by the thruster) needs to grab and recover the robot vehicle, unlike some underwater robots based on magnetic adsorption movement that are difficult to grab and recover because the magnetic adsorption effect is too strong, the submarine ultrasonic non-destructive testing wall-climbing robot vehicle adsorbed by the thruster only needs to control the thruster and wheels 13 to stop moving to be easily recovered, and the 6 screw holes above the upper cover plate 15 can be used to assemble special accessories such as hooks to achieve special functions, such as enabling the mother machine to grab it.

[0066] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. Persons skilled in the art will readily appreciate that variations and modifications may be made without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A propeller-adsorbed submarine ultrasonic nondestructive testing wall-climbing robot vehicle, characterized in that: The invention comprises a vehicle body, and a propeller, an ultrasonic nondestructive testing device and a motion mechanism installed on the vehicle body; the propeller comprises an electric motor, a blade, a shell, a bracket, a front cover, a rear cover and a control system; the function of the propeller is mainly to provide the robot with a thrust to make it fit against the pipeline wall when the robot moves in a circle on the pipeline wall and performs detection operations; the number and distribution of the propellers will affect the complexity of the force applied to the robot, the stability of the movement and the difficulty of its motion control. In order to prevent the robot from moving offset or rolling over due to uneven force, resulting in the inability to stably perform circumferential movement around the submarine pipeline and to avoid overly complex control, considering the overall The gravity, the thrust that the thruster can provide, the buoyancy and resistance after entering the sea, the support and friction of the pipeline on the robot vehicle, and the design of the mechanism position around the robot vehicle, the number of thrusters is selected to be two, which is enough to keep the robot vehicle close to the surface of the submarine pipeline and make stable circumferential motion; in order to make the robot vehicle bear the force evenly during the movement and offset the reverse torque generated by the two thrusters, the thrusters are symmetrically mounted on the left and right sides of the vehicle body, and the propellers of the two thrusters rotate in opposite directions, one side has a positive propeller and the other side has a reverse propeller, and the thrusts generated by the thrusters are in the same direction, both toward the center of the pipeline; the propeller blades generate propulsion through rotation, so that the robot can It is adsorbed on the surface of the submarine pipeline, and the rotation of the blades is divided into forward and reverse rotation. Considering that the thrust is large during forward rotation, it is easy to achieve stable wall-adhering movement and accurate detection of the robot vehicle, so forward rotation is adopted, and it is manufactured by 3D printing using plastic materials; the motor of the thruster is responsible for providing power and transmitting the power to the thruster blades to rotate, thereby driving the thruster to operate, and a corrosion-resistant and long-life underwater motor is adopted, with a rated voltage of 24V; the shell, bracket, front cover, and rear cover play an important role in the structure of the thruster; the shell is the external structure of the thruster, which mainly provides protection and support, and can accommodate the internal thruster The bracket is an internal structure of the propeller, used to support and fix the various components of the propeller, and has sufficient strength and rigidity to withstand the thrust and vibration generated by the propeller, ensure that the propeller remains stable during operation, and prevent the misalignment or damage of the various components; due to the large resistance of water, the bracket is designed to be streamlined to reduce the resistance of water and improve the propulsion efficiency; the front end cover and the rear end cover are located at both ends of the propeller, and are also designed to be streamlined to reduce the resistance of water and improve the propulsion efficiency; the shell, bracket, front end cover and rear end cover are manufactured by 3D printing using plastic materials;The control system adopts PWM control, and controls the speed and direction of the motor through the electronic speed regulator, so as to control the rotation speed and direction of the propeller blades, change the thrust of the propeller, so that the submarine ultrasonic non-destructive testing wall-climbing robot can be firmly adsorbed on the surface of the submarine pipeline, adapt to the movement of the robot at different positions under different stress conditions around the pipeline, realize the adhesion and detachment of the submarine ultrasonic non-destructive testing wall-climbing robot and the submarine pipeline, and finally realize the stable circumferential movement of the wheeled robot along the submarine pipeline; through the force analysis of the robot gravity, the support and friction of the pipeline on the robot, the buoyancy and resistance of the robot, and the thrust of the propeller, and calculate The thrust of the propeller required when the robot vehicle is at different positions in the pipeline can be determined by setting the motor speed to make the propeller provide appropriate thrust. When the motor stops, the robot vehicle can fall off the pipeline. The ultrasonic non-destructive testing device includes a pair of TOFD probes, a camera, a waterproof lamp, a clamping mechanism and a screw moving scanning mechanism, which are assembled in front of the vehicle body. The TOFD probe is a broadband narrow pulse probe, one transmitting and one receiving, which are symmetrically arranged relative to the center line of the weld. The transmitting probe generates a non-focused longitudinal wave beam, which is incident on the inspected workpiece at a certain angle. Part of the beam is propagated along the near surface and received by the receiving probe, and the other part of the beam is received by the receiving probe after being reflected by the bottom surface or diffracted by the defect. The A-scan signal is finally formed, and the phase and amplitude of the signal are converted into a 256-level grayscale image to obtain a TOFD-D detection image that can be used to identify defects. Therefore, the robot can analyze and determine the number, position and size of defects through the diffraction signals at the upper and lower endpoints of the defects and their propagation time difference, thereby realizing ultrasonic non-destructive internal defect detection of submarine pipelines and improving the safety and reliability of pipelines; the camera is used for target recognition, capturing the appearance, shape and detailed information of the target to be detected, providing visual information, helping staff to locate and evaluate the area to be detected, and detecting whether the weld is located on the symmetrical center line of the two TOFD probes. When the robot moves If the weld deviates from the symmetrical center line of the two TOFD probes, the staff can control the screw to move the scanning mechanism to adjust the lateral position of the two TOFD probes in real time through the information feedback of the camera, so that the weld is relocated on the symmetrical center line of the two TOFD probes; the working environment of the robot vehicle is usually deep sea, the light conditions are poor, and it is impossible to directly rely on natural light for observation and detection. Therefore, the waterproof lamp is used to provide sufficient lighting to ensure that the camera can obtain a clear image; the waterproof lamp can work in an underwater environment and generate light of sufficient brightness, so that the camera can accurately identify the target and capture a clear image, ensuring the accuracy and reliability of the detection work;The clamping mechanism and the lead screw moving scanning mechanism are used to adjust the TOFD probe to a suitable position and angle, so that the dual probes fit tightly on the surface of the submarine pipeline and the weld is located on the symmetrical center line of the two probes. The clamping mechanism can adjust the longitudinal position and pitch angle of the TOFD probe, and the lead screw moving scanning mechanism can adjust the lateral position and pitch angle of the TOFD probe, which are driven by a motor and driven by a reciprocating lead screw. Angle adjustment plates are fixed on both sides of the fixing seat in the clamping mechanism, and a rotating guide rail is hingedly connected to the bottom end. The rotating guide rail is fixed to the angle adjustment plate by bolt I, and the rotation of the two is limited by tightening bolt I. The pitch angle of the probe is changed by adjusting the relative position of the rotating guide rail and the angle adjustment plate. The angle adjustment plate is roughly adjusted manually according to the outer diameter of the pipeline to be detected. The angle plate of the clamping mechanism and the lead screw moving scanning mechanism makes the TOFD probe fit the pipe wall excessively to complete the coarse adjustment; when the robot vehicle is adsorbed on the pipe wall through the thruster, the clamping mechanism is supported by the pipe wall, so that the probe base hinged on the U-shaped block is forced to rotate, and at the same time, the four springs are forced to deform and provide tension and thrust, thereby driving the U-shaped block to rotate around bolt II, and driving the mounting seat fixed on the slider to move along the vertical slide groove of the rotating guide rail. After the four springs are balanced, they will maintain the position of these moving parts to complete the fine adjustment of the position and angle of the two TOFD probes; by using springs and hinges, the two TOFD probes are always tightly fitted to the pipe surface during the movement of the robot vehicle, changing the longitudinal position and pitch angle of the probe; the springs have a great impact on the clamping mechanism. The elastic force of each component in the mechanism enables the robot to keep the bottom surface of the probe base in close contact with the pipe wall when encountering an uneven pipe surface; the integrated servo drive motor in the screw moving scanning mechanism drives the driving wheel to rotate, thereby driving the cylindrical gear and the driven wheel to rotate, and the driven wheel in turn drives the reciprocating screw fixed to it to rotate, and the reciprocating screw transmission causes the screw nut to move laterally, and the TOFD probe is assembled in the clamping mechanism, and the camera, waterproof lamp and two clamping mechanisms are installed together on a base plate, and the base plate is assembled on the screw nut, so the screw moving scanning mechanism can adjust the lateral position of the probe; the scanning connection angle plate and the scanning connection base plate in the screw moving scanning mechanism are connected by bolt III, fixing bolts and graphite copper sleeve bearings, and by tightening the fixing screws The bolt is used to limit the rotation of the two. The reciprocating screw will automatically return after the transmission reaches the limit stroke to avoid mechanical jamming and motor damage. At the same time, the active stroke of the screw scanning mechanism is 150mm, and the manually adjustable pitch angle is 0-65°, so that the dual TOFD probes can fit the pipeline. The motion mechanism includes two sets of wheel drive mechanisms and four wheels. The four wheels are symmetrically distributed on the left and right sides of the robot, assembled on the wheel drive mechanism, and equipped with tires. The two sets of wheel drive mechanisms are fixed inside the vehicle body and isolated from the circuits and circuit boards inside the vehicle body by a shielding cover. The wheels are used as the moving parts of the robot vehicle. They are used to push the robot vehicle to move on the surface of the submarine pipeline by rotation. As the support point at the bottom of the robot vehicle, they can provide stable support.Through the contact area of ​​the wheels, the robot can disperse the weight and maintain balance, thereby maintaining stability on the uneven surface of the submarine pipeline; and the tires with asymmetric patterns can improve the movement stability of the robot and reduce noise; the driving motor in the wheel driving mechanism drives the power gear to rotate, thereby driving the gear and the helical gears I and II located on the same crossbar as the gear to rotate, and then drives the helical gears III and IV to rotate, and finally drives the two wheels on the same side to rotate; the vehicle body is used to place the wheel driving mechanism, circuits and circuit boards, and is connected to the wheels, propellers and ultrasonic non-destructive testing devices, and its upper cover plate is designed with two through holes to allow the two propellers to rotate. The wires of the feeder are connected to the circuit board in the vehicle body through M8 hollow waterproof sealing screws, and the rear connector cover is designed with five holes for installing metal waterproof connectors to allow the wires of the two TOFD probes, camera, waterproof light and external power supply to pass through and connect to the circuit board; the vehicle body is designed with grooves for installing sealing rings to meet the sealing requirements and prevent the internal motor, circuit and circuit board from being damaged by water. The sealing between the lead screw moving scanning mechanism, the axle end cover, the upper cover plate and the connector cover plate and the lower shell of the vehicle adopts nitrile rubber sealing rings, and the dynamic seal at the wheel axle adopts skeleton oil seal sealing rings; the robot is suitable for submarine pipelines with a diameter greater than or equal to 400mm. ;

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