Modularized reconfigurable snakelike underwater pipeline operation robot and working method thereof

Abstract

The invention relates to a modular reconfigurable snakelike underwater pipeline operation robot and a working method thereof, and belongs to the technical field of underwater robots, the modular reconfigurable snakelike underwater pipeline operation robot is formed by connecting a head joint, a plurality of middle joints and a tail joint in series, and the head joint, the middle joints and the tail joint are connected end to end and then enclose the outer wall of a pipeline in a closed loop. The number of joints can be flexibly reconstructed according to the pipe diameter of the underwater pipeline. In order to overcome the defect that a flexible robot is difficult to stabilize a closed loop due to underwater disturbance, a conical structure is used for passively compensating pose deviation caused by water flow, it is ensured that a head module and a tail module can still be accurately aligned and rigidly locked within the angle tolerance, and therefore 360-degree full-wrapping firm nodes are rapidly formed in a complex vertical pipe and jacket network. Besides, a plurality of robots can be networked to cooperatively work and jointly complete lifting, lowering and carrying operation of the heavy damaged pipeline, efficient and reliable technical support is provided for maintenance and overhaul of the underwater pipeline, and ocean engineering and underwater operation technology development is assisted.

Description

Technical Field

[0001] This invention relates to a modular, reconfigurable snake-shaped underwater pipeline operation robot and its working method, belonging to the field of underwater robot technology. Background Technology

[0002] Subsea pipelines are critical facilities laid in rivers, lakes, and seas to transport liquids, gases, or loose solids. Their safe operation is essential for offshore oil and gas development and environmental protection. With increasing service life, subsea pipelines are highly susceptible to corrosion, structural deformation, or rupture. Therefore, regular external non-destructive testing and maintenance inspections are indispensable. Since some long-distance pipelines are deeply buried beneath the seabed, current external testing and operations primarily focus on pipe sections exposed in the water, especially vertically distributed risers and interlocking jacket structures on offshore platforms. These facilities are subjected to the direct impact of variable ocean currents over long periods, placing extremely high demands on the flexibility, close-range engagement, and obstacle-crossing capabilities of testing robots. In recent years, using underwater robots equipped with testing instruments for in-situ detection has become a mainstream trend. However, existing equipment still has significant limitations in practical applications, especially given the complex seabed topography and varying pipe diameters.

[0003] Currently, robots used for underwater pipeline flaw detection mainly fall into three types: fixed ring type, adaptive spring support type, and rigid linkage clamping type. For fixed ring type devices, for example, patent application number 202311780569.X discloses an underwater pipeline flaw detection robot. This device uses a main ring to enclose the robot entirely on the pipeline for mobile flaw detection. However, this fixed closed-loop structure requires the robot to be inserted from one end of the pipeline and removed from the other, making it only suitable for short, straight underwater pipelines. For long-distance subsea pipelines or complex risers with numerous flanges, this device cannot be flexibly disassembled and reassembled in the middle of the pipeline.

[0004] To improve pipe diameter adaptability and facilitate mid-section installation, some equipment employs adaptive adjustment or opening / closing clamping structures. For example, patent application number 202210721849.2 discloses an underwater oil pipeline flaw detection robot that uses an adjustable detection clamp with a directional control spring to adapt to different pipe diameters. However, this spring-driven device has limited stability in its wrapping and fitting under complex ocean currents. More challenging is the fact that damaged pipelines, affected by seabed subsidence or external impacts, often require in-situ repair, casing replacement, or new pipe laying. This necessitates first lifting, smoothly lowering, or precisely relocating the heavy underwater pipeline as a whole. However, the limited thrust of the aforementioned individual robots is clearly insufficient for such heavy-duty operations.

[0005] To enhance clamping stability, patent application number 202310181049.0 discloses an intelligent multi-directional controllable X-ray flaw detection device for underwater and above-water pipelines. This device employs a basic frame and assembly clamping rod structure, clamping the pipeline via opening and closing push rods, and utilizing axially moving electric drive wheels and a pivoting structure to perform moving flaw detection on the pipeline. However, this mechanical structure, relying on multiple sets of rigid assembly clamping rods (such as the first, second, and third assembly clamping rods) folding and clamping together, is quite large and cumbersome. Its adaptability to drastic changes in pipe diameter is limited by the fixed dimensions of the rigid rods. Furthermore, the complex external wheel drive mechanism has poor obstacle-crossing ability when facing pipe flanges or surface attachments. As a single inspection tool, it still cannot achieve multi-machine collaborative lifting, lowering, and relocation of damaged pipelines for heavy-duty operations.

[0006] Therefore, existing marine pipeline operation robots cannot simultaneously handle the flexible reconfiguration of mid-sections of long-distance pipelines, the precise closed-loop fitting of multi-diameter pipes, and lack the comprehensive capability for multi-robot collaborative pipeline lifting and transportation. These shortcomings severely restrict the development of deep-water pipeline maintenance and repair technologies, becoming a technical bottleneck that urgently needs to be addressed. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention proposes a modular, reconfigurable serpentine underwater pipeline operation robot and its working method. This robot can flexibly reconfigure the number of its joints according to different specifications of underwater pipelines, enabling precise flaw detection operations on pipelines of varying diameters. To overcome the challenge of stable closed-loop operation caused by underwater disturbances, this invention innovatively proposes a composite docking mechanism combining electromagnetic long-range guidance, conical self-alignment with differential alignment, and multi-point locking. This design utilizes a conical structure to passively compensate for positional deviations caused by water flow, ensuring precise alignment and rigid locking of the head and tail modules within a ±10° angular tolerance. This allows for the rapid formation of a robust, 360-degree fully enclosed node in complex networks of risers and jacket supports. Furthermore, multiple robots can network and collaborate, adjusting thrust vectors via thruster rotation motors to jointly lift, lower, and transport heavily damaged pipelines. This provides efficient and reliable technical support for underwater pipeline maintenance and repair, contributing to the development of marine engineering and underwater operation technologies.

[0008] The present invention adopts the following technical solution:

[0009] A modular and reconfigurable snake-shaped underwater pipeline operation robot is composed of a head joint, several intermediate joints, and a tail joint connected in series.

[0010] Among them, multiple intermediate joints adopt a standardized and consistent structural design, with identical structures. The number of intermediate joints is increased or decreased according to the outer diameter of the pipe to change the overall length of the robot, thereby achieving adaptation to different pipe diameters. A head joint, several intermediate joints, and a tail joint are connected end to end and form a closed loop around the outer wall of the pipe.

[0011] Preferably, the intermediate joint is formed by two modules connected by a rotating joint. One end of one module is provided with a joint connecting flange, and the other end of the other module is provided with a joint connecting groove. Each module is provided with an ultrasonic detector and a shock-absorbing wheel mechanism, which are fixedly installed on the upper part of the module.

[0012] A drive mechanism is provided at the bottom of the module on one side of the joint connection groove.

[0013] When performing pipeline flaw detection, the system calculates the relative deflection angle required for each rotating joint based on the total number of joints connected in series, and controls the servo motor inside each rotating joint to rotate synchronously at the corresponding angle, driving the robot to bend inward as a whole, so that the head joint and tail joint can be precisely closed and mechanically docked to form a stable closed-loop embrace shape.

[0014] Preferably, a spring contact pin is provided at the center of the joint connecting flange, and multiple locating pins are symmetrically and evenly arranged between the spring contact pin and the joint connecting flange.

[0015] The joint connection groove has a pad at its center that mates with a spring contact pin, and a positioning groove that mates with a positioning pin is provided between the pad and the joint connection groove. In this invention, the pads are evenly distributed in the central area of ​​the end face of the joint connection groove, corresponding to the distribution of the spring contact pins. The two are connected to achieve electrical connection of each joint of the underwater snake robot. The pads here are actually highly conductive planar contact pads. Before the robot is deployed underwater, the corresponding number of joints are pre-assembled and locked on land. During the connection of adjacent joints, the spring contact pin at one end is compressed, and the physical elasticity of the internal spring presses it tightly against the pad at the other end. This method does not require any soldering iron welding; a stable electrical connection can be achieved solely through mechanical pressing.

[0016] Preferably, the drive mechanism is a propeller thruster, including a propeller motor, a thruster rotating shaft, a thruster rotating motor, a thruster guard, and a propeller.

[0017] Preferably, the rotating joint includes a servo output flange, a servo, a servo bracket, a joint docking end plate, a friction retaining ring, a joint end cover, and a joint encapsulation end cover. The servo is securely mounted inside the joint encapsulation end cover via the servo bracket, and the torque output ends on both sides of the servo are fixedly connected to the servo output flange. The joint end cover is fixed to both sides of the joint docking end plate and is connected to the servo output flange via a spline, thereby converting the torque of the servo into relative deflection motion between adjacent joints.

[0018] Meanwhile, a friction retaining ring is provided between the mating surfaces of the joint docking end plate and the joint encapsulation end cover to effectively reduce friction and wear caused by relative rotation of the joint.

[0019] Preferably, the shock absorber mechanism includes a shock absorber, a bearing, a shock absorber positioning pin, a shock absorber connecting shaft, a shock absorber support, and a shock absorber spring;

[0020] The shock absorber support is fixed to the top of the module. The shock absorber support has grooves on both sides, and shock absorber positioning pins are vertically installed in the grooves on both sides. Guide holes are opened on both shock absorber positioning pins. The two ends of the shock absorber connecting shaft are respectively sleeved through the guide holes, and shock absorber springs are sleeved on the shock absorber positioning pins.

[0021] The shock absorber wheel has a circular hole at its center, and the bearing is nested and fixed inside the circular hole. The middle section of the shock absorber wheel connecting shaft passes through and is fixed to the inner ring of the bearing. The shock absorber wheel is mounted on the shock absorber wheel connecting shaft by rotating through the bearing.

[0022] Preferably, the basic structure of the head joint is similar to that of the intermediate joint, except that the mating surface of the head joint is provided with a protruding conical mating structure, an iron plate (as an electromagnetic adsorption target) is fixedly embedded in the center of the front end of the conical mating structure, and an annular snap-locking groove is opened on the outer periphery of the middle section of the conical mating structure.

[0023] The basic structure of the tail joint is similar to that of the intermediate joint. The difference is that the end face of the tail joint is concave to form a conical groove. The taper of the conical groove is perfectly matched with the conical docking structure of the head joint. An electromagnet (for magnetic guidance in conjunction with the head plate) is fixedly installed at the bottom of the conical groove. Four radially retractable buckles are evenly distributed along the circumference on the inner wall of the conical groove.

[0024] Preferably, the tail joint is provided with a latching drive module, which includes a latching spring, an electromagnet and a latching rotating support. Four latches are slidably mounted radially on the inner wall of the conical groove. A latching spring is provided on the back (inner) side of the latch to provide a reset thrust. A cylindrical pin is vertically provided at the bottom of each latch. The cylindrical pin extends downward and is inserted into the guide slot of the latching rotating support at the bottom. The center of the latching rotating support is fixedly connected to the torque output end of the servo motor.

[0025] Preferably, the buckle rotating support is a disc surface with four evenly distributed curved grooves (or eccentric grooves) on the disc surface, which respectively cooperate with the cylindrical pins at the bottom of the four buckles. During operation, the servo motor outputs torque to drive the buckle rotating support to rotate at a certain angle. The curved grooves on the buckle rotating support drive the four cylindrical pins to synchronously contract inward or expand outward radially through the action of the cam, thereby driving the buckles to overcome the buckle spring resistance and make radial linear motion, so as to achieve rigid locking or release of the head joint.

[0026] A working method for the aforementioned modular reconfigurable snake-shaped underwater pipeline operation robot involves the following steps: First, based on the diameter of the pipeline to be inspected, each intermediate joint is controlled to bend synchronously at a preset angle, causing the head joint to gradually converge towards the tail joint. During this process, an electromagnet inside the tail joint is energized to generate a magnetic field. When the iron plate at the front end of the head joint enters the magnetic attraction range, the position and angle deviations caused by underwater disturbances are compensated by the magnetic guidance and the self-centering effect of the conical docking structure, guiding the tail joint and head joint to achieve highly fault-tolerant and precise alignment. After alignment, the latch of the tail joint will automatically engage with the self-locking groove of the head joint, completing a rigid mechanical lock. At this point, the electromagnet is de-energized to reduce the overall energy consumption of the system, and the robot's head and tail dock together to form a stable closed-loop structure, achieving 360-degree full coverage and encirclement of the pipeline.

[0027] After completing the encirclement, the control system rotates all propeller thrusters to the axial forward direction and activates them. The hydrodynamic force generated by the propeller thrusters provides the robot with the driving force for translational movement along the pipe, while simultaneously generating inward pressure to adhere to the pipe. During movement, ultrasonic detectors are simultaneously triggered to perform continuous non-destructive testing on the pipe. During operation, the shock-absorbing wheels transmit the radial impact force received to the internal shock-absorbing wheel connecting shaft through bearings. During this shock absorption and retraction process, the shock-absorbing wheels, relying on the bearings, can still maintain free rolling motion against the pipe wall. This design effectively converts sliding friction into rolling friction, preventing scratches on the pipe wall. When the shock-absorbing wheel connecting shaft is compressed, it slides downwards along the shock-absorbing wheel positioning pins on both sides, carrying the shock-absorbing wheel with it. As the connecting shaft moves downwards, the shock-absorbing wheel spring, fitted at the bottom of the positioning pins (between the connecting shaft and the bottom support), is compressed, absorbing the rigid impact energy from the protrusion and providing flexible cushioning. After the shock-absorbing wheel rolls over the protrusion, the spring releases its elastic potential energy and rebounds, pushing the connecting shaft upwards and causing the shock-absorbing wheel to return to its initial outermost contact position. This structure allows the shock-absorbing wheel to undergo radial displacement along the positioning pin direction when compressed, utilizing the compression and rebound of the spring to provide flexible cushioning against protrusions on the pipe wall.

[0028] The shock-absorbing wheel of this invention not only transforms the sliding friction between the equipment and the outer wall of the pipe into rolling friction, effectively avoiding secondary damage to the pipe wall; but also its built-in spring's flexible stroke can adaptively buffer the rigid impact caused by the pipe flange connection or surface protrusions, greatly ensuring the posture stability of continuous flaw detection operations and the reliability of equipment operation.

[0029] Preferably, when performing heavy-load handling or orientation adjustment operations on underwater pipelines, multiple robots are first distributed sequentially along the axial direction of the pipeline to be handled. Each robot independently controls its joints to bend synchronously at a preset angle according to the outer diameter of the pipeline until the end modules are precisely docked and locked together, thus forming multiple stable and rigid closed-loop fully enclosed nodes in different sections of the pipeline. Subsequently, each robot uses a thruster rotation motor to synchronously rotate the propeller thrusters arranged on both sides to the vertical upward vector direction (or the required target force direction) and start them in unison. Relying on the coordinated orientation calculation of the multi-robot array and the synchronous vector thrust output of the thruster group by the control system, the load-bearing capacity of the large pipeline can be evenly distributed on each enclosed node. Through this multi-point distributed thrust collaboration, the robot swarm can overcome the self-weight of the large pipeline and the resistance of complex ocean currents, and finally achieve the overall lifting, smooth lowering, and high-precision relocation and handling of damaged or unlaid underwater pipelines, greatly expanding the operational boundaries of individual detection robots.

[0030] Vertically upward refers to the direction perpendicular to the sea level.

[0031] For any details not covered in this invention, please refer to the prior art.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention proposes a modular, reconfigurable serpentine underwater pipeline operation robot and its working method. By flexibly adding or removing intermediate joint modules, it can adapt to underwater pipelines of different diameters, effectively overcoming the limitation of traditional rigid equipment in adapting to different pipe diameters. It achieves 360-degree full-coverage precise fitting and high-stability flaw detection. Addressing the challenge of unreliable docking due to underwater disturbances, this invention innovatively employs electromagnetic guidance and a conical, high-fault-tolerant docking structure. This structure provides passive pose compensation and self-centering effect within a ±10° angular tolerance, and, combined with internal latches, achieves rapid rigid locking, ensuring the accuracy of underwater end-to-end closed-loop operation and the safety of continuous operation. Furthermore, this invention achieves flexible adjustment of thrust vector through a thruster rotary motor, significantly improving the maneuverability and obstacle-crossing ability of a single robot. It also enables multiple robots to network and collaborate in a cluster. Relying on multi-robot distributed rigid encirclement and synchronous thrust vector control, the robot cluster can effectively handle heavy-load operations such as overall lifting, smooth lowering, and precise relocation of heavily damaged underwater pipelines, breaking the limitations of traditional underwater flaw detection equipment with its single function. Attached Figure Description

[0034] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0035] Figure 1 This is a schematic diagram of the overall mechanism of the modular reconfigurable snake-shaped underwater pipeline operation robot of the present invention;

[0036] Figure 2 This is a schematic diagram of the embracing mode of the modular reconfigurable snake-shaped underwater pipeline operation robot of the present invention;

[0037] Figure 3 This is a schematic diagram of the intermediate joint module structure of the present invention. Figure 1 ;

[0038] Figure 4 This is a schematic diagram of the intermediate joint module structure of the present invention. Figure 2 ;

[0039] Figure 5 This is an exploded view of the interior of the rotating joint of the present invention;

[0040] Figure 6 This is a schematic diagram of the shock-absorbing wheel mechanism of the present invention;

[0041] Figure 7 This is a schematic diagram of the head joint of the present invention;

[0042] Figure 8 This is a schematic diagram of the tail joint of the present invention;

[0043] Figure 9 This is a longitudinal sectional view of the internal structure of the tail joint of the present invention;

[0044] Figure 10 This is a schematic diagram of the snap-fit ​​rotating support of the present invention;

[0045] Figure 11 This is a schematic diagram of the pipeline flaw detection working state of the present invention;

[0046] Figure 12 This is a schematic diagram of a multi-machine coordinated pipeline lifting / lowering operation.

[0047] Among them, 1-head joint, 2-intermediate joint, 3-tail joint, 4-ultrasonic detector, 5-shock absorber wheel, 6-locating pin, 7-propeller guard, 8-propeller, 9-joint connecting flange, 10-spring contact pin, 11-locating groove, 12-joint connecting groove, 13-welding pad, 14-propeller motor, 15-propeller rotating shaft, 16-servo output flange, 17-servo, 18-servo bracket, 19-joint 20-Friction retaining ring, 21-Joint end cap, 22-Joint encapsulated end cap, 23-Bearing, 24-Shock absorber positioning pin, 25-Shock absorber connecting shaft, 26-Shock absorber support, 27-Shock absorber spring, 28-Iron sheet, 29-Snap-on self-locking groove, 30-Snap-on, 31-Electromagnet, 32-Thruster rotary motor, 33-Snap-on rotating support, 34-Snap-on spring, 35-Thruster support, 36-Pipe. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. However, this is not the only description; all aspects not described in detail herein are based on conventional techniques in the art.

[0049] Example 1

[0050] A modular, reconfigurable snake-like underwater pipeline operation robot, such as Figure 1 As shown, it is composed of a head joint 1, several intermediate joints 2 and a tail joint 3 connected in series;

[0051] Among them, multiple intermediate joints 2 adopt a standardized and consistent structural design, with identical structures. The number of intermediate joints 2 is increased or decreased according to the outer diameter of the pipe to change the overall length of the robot, thereby achieving adaptation to different pipe diameters. A head joint 1, several intermediate joints 2, and a tail joint 3 are connected end to end and form a closed loop around the outer wall of the pipe, such as... Figure 2 .

[0052] Example 2

[0053] A modular, reconfigurable serpentine underwater pipeline operation robot, as described in Embodiment 1, differs in that its intermediate joint is formed by two modules connected by a rotating joint. One module has a joint connecting flange 9 at one end, and the other module has a joint connecting groove 12 at the other end. Each module is equipped with an ultrasonic detector 4 and a shock-absorbing wheel mechanism, which are fixedly installed on the upper part of the module. Figure 3 ;

[0054] A drive mechanism is installed at the bottom of the module on one side of the joint connecting groove 12.

[0055] When performing pipeline flaw detection, the system calculates the relative deflection angle required for each rotating joint based on the total number of joints connected in series, and controls the servo motor inside each rotating joint to rotate synchronously at the corresponding angle, driving the robot to bend inward as a whole, so that the head joint 1 and the tail joint 3 can be precisely joined and mechanically docked to form a stable closed-loop embrace shape.

[0056] Example 3

[0057] A modular and reconfigurable snake-shaped underwater pipeline operation robot, as described in Embodiment 2, except that a spring contact pin 10 is provided in the center of the joint connecting flange 9, and multiple positioning pins 6 are symmetrically and evenly arranged between the spring contact pin 10 and the joint connecting flange 9.

[0058] like Figure 4 As shown, a solder pad 13 is provided at the center of the joint connection groove 12 to cooperate with the spring contact pin 10. A positioning groove 11 is provided between the solder pad 13 and the joint connection groove 12 to cooperate with the positioning pin 6. In this invention, the solder pads 13 are evenly distributed in the central area of ​​the end face of the joint connection groove 12, corresponding to the distribution of the spring contact pins 10. The two can be connected to realize the electrical connection of each joint of the underwater snake robot. The solder pads 13 here are actually planar contact pads with high conductivity. Before the robot is deployed underwater, the corresponding number of joints are pre-assembled and locked on land. During the connection of adjacent joints, the spring contact pin 10 at one end is compressed and pressed tightly against the solder pad 13 at the other end by the physical elasticity of the internal spring. This method does not require any soldering iron welding and can achieve a stable electrical connection by mechanical pressing alone.

[0059] Example 4

[0060] A modular and reconfigurable snake-shaped underwater pipeline operation robot, as described in Embodiment 3, differs in that the drive mechanism is a propeller thruster, including a propeller motor 14, a thruster support 35, a thruster rotating shaft 15, a thruster rotating motor 32, a thruster mesh cover 7, and a propeller 8.

[0061] Example 5

[0062] A modular, reconfigurable serpentine underwater pipeline operation robot, as described in Example 4, differs in that... Figure 5 The rotating joint includes a servo output flange 16, a servo motor 17, a servo motor bracket 18, a joint docking end plate 19, a friction retaining ring 20, a joint end cover 21, and a joint encapsulation end cover 22. The servo motor 17 is securely mounted inside the joint encapsulation end cover 22 via the servo motor bracket 18, and the torque output ends on both sides of the servo motor 17 are fixedly connected to the servo output flange 16. The joint end cover 21 is fixed to both sides of the joint docking end plate 19 and is connected to the servo output flange 16 via a spline, thereby converting the torque of the servo motor 17 into relative deflection motion between adjacent joints.

[0063] Meanwhile, a friction retaining ring 20 is provided between the mating surfaces of the joint docking end plate 19 and the joint encapsulation end cover 22 to effectively reduce friction and wear caused by relative rotation of the joint.

[0064] Example 6

[0065] A modular, reconfigurable, serpentine underwater pipeline operation robot, as described in Example 5, differs in that... Figure 6 The shock absorber mechanism includes a shock absorber 5, a bearing 23, a shock absorber positioning pin 24, a shock absorber connecting shaft 25, a shock absorber support 26, and a shock absorber spring 27.

[0066] The shock absorber support 26 is fixed to the top of the module. The shock absorber support 26 has grooves on both sides, and shock absorber positioning pins 24 are vertically installed in the grooves on both sides. Guide holes are opened on both shock absorber positioning pins 24. The two ends of the shock absorber connecting shaft 25 are respectively sleeved through the guide holes, and shock absorber springs 27 are sleeved on the shock absorber positioning pins 24.

[0067] The shock absorber 5 has a circular hole in the center, and the bearing 23 is nested and fixed in the circular hole. The middle section of the shock absorber connecting shaft 25 passes through and is fixed to the inner ring of the bearing 23. The shock absorber 5 is rotatably mounted on the shock absorber connecting shaft 25 through the bearing 23.

[0068] Example 7

[0069] A modular, reconfigurable, serpentine underwater pipeline operation robot, as described in Example 6, differs in that... Figure 7 The basic structure of the head joint is similar to that of the intermediate joint. The difference is that the head joint has a protruding conical docking structure on the docking surface. An iron plate 28 (as an electromagnetic adsorption target) is fixedly embedded in the center of the front end of the conical docking structure. An annular self-locking groove 29 is opened on the outer periphery of the middle section of the conical docking structure.

[0070] like Figure 8 The basic structure of the tail joint is similar to that of the intermediate joint. The difference is that the end face of the tail joint is concave to form a conical groove. The taper of the conical groove is perfectly matched with the conical docking structure of the head joint. An electromagnet 31 (used to cooperate with the head iron plate for magnetic guidance) is fixedly installed at the bottom of the conical groove. On the inner wall of the conical groove, four radially retractable buckles 30 are evenly distributed along the circumference.

[0071] In this embodiment, the draft angle of the protruding conical docking structure is 20°. Theoretically, mechanical jamming will not occur if the docking deviation angle is less than 20°. However, considering the resistance and smoothness of underwater dynamic docking, this embodiment introduces the classic 50% engineering safety margin, setting the tolerance to half, or ±10°, to ensure that the conical surface can provide sufficient passive correction and guiding force.

[0072] Example 8

[0073] A modular, reconfigurable serpentine underwater pipeline operation robot, as described in Example 7, except that... Figure 9 The tail joint is equipped with a latch drive module, which includes a latch spring 34, an electromagnet 31 and a latch rotation support 33. Four latches 30 are slidably mounted on the inner wall of the conical groove along the radial direction. The latch spring 34 is provided on the back (inner) side of the latch 30 to provide a reset thrust. A cylindrical pin is vertically provided at the bottom of each latch. The cylindrical pin extends downward and is inserted into the guide slot of the latch rotation support at the bottom. The center of the latch rotation support 33 is fixedly connected to the torque output end of the servo motor.

[0074] The snap-fit ​​rotating support 33 is a disc surface, such as... Figure 10 As shown, four evenly distributed curved grooves (or eccentric grooves) are opened on the disc surface, which respectively cooperate with the cylindrical pins at the bottom of the four latches. During operation, the torque output by the servo motor drives the latch rotating support 33 to rotate at a certain angle. The curved grooves on the latch rotating support 33 drive the four cylindrical pins to synchronously contract inward or expand outward along the radial direction through the action of the cam, thereby driving the latch to overcome the latch spring resistance and make radial linear motion, so as to achieve rigid locking or release of the head joint.

[0075] It should be noted that in this embodiment, the buckle and the inner wall of the conical groove have a slight clearance fit. A radial straight groove is designed inside the through hole on the inner side wall of the conical groove. The overall design uses a buckle + cylindrical pin + straight groove in the through hole + curved groove of the rotating base. The cylindrical pin below the buckle passes through the straight groove and then inserts into the curved groove of the buckle's rotating support. Specifically, when the cylindrical pin is moved, the curved groove of the buckle's rotating support provides a slanted normal force, which generates lateral compression, causing sidewall friction. However, to avoid "dead points," a steep curve is not used in the design of the curved groove on the disc surface; instead, a gentle eccentric involute curve is employed. The core purpose of this curve design is to strictly control the pressure angle during transmission, ensuring that it remains significantly smaller than the equivalent friction angle of the guide groove interface throughout the entire extension and retraction stroke of the buckle. Therefore, when the snap-lock rotating support rotates, the curved groove on the snap-lock rotating support can only act like a cam, pushing the cylindrical pin in a purely radial linear motion along the straight groove in the through hole, without causing mechanical interference.

[0076] Example 9

[0077] A modular, reconfigurable, serpentine underwater pipeline operation robot operates by first controlling each intermediate joint to bend synchronously at a preset angle according to the diameter of the pipeline 36 to be inspected, so that the head joint 1 gradually closes towards the tail joint 3. Figure 11During this process, the electromagnet inside the tail joint 3 is energized to generate a magnetic field. When the iron plate 28 at the front end of the head joint enters the magnetic attraction range, the position and angle deviation caused by underwater disturbances can be compensated by the magnetic guidance and the self-centering effect of the conical docking structure, guiding the tail joint 3 and the head joint 1 to achieve highly fault-tolerant and precise alignment. After alignment, the latch 30 of the tail joint 3 will be inserted into the latch self-locking groove 29 of the head joint to complete the rigid mechanical locking. At this time, the electromagnet is de-energized to reduce the overall energy consumption of the system. The robot's head and tail dock to form a stable closed-loop structure, achieving 360-degree full coverage and encirclement of the pipeline.

[0078] After completing the encirclement, the control system rotates all propeller thrusters to the axial forward direction and starts them. The hydrodynamic force generated by the propeller thrusters provides the robot with the driving force to translate along pipe 36, while simultaneously generating inward pressure to move along the pipe. During this movement, the ultrasonic detector 4 is simultaneously triggered to perform continuous non-destructive testing on the pipe. During operation, the shock-absorbing wheels transmit the radial impact force received to the internal shock-absorbing wheel connecting shaft through bearings. During this shock absorption and retraction process, the shock-absorbing wheels, relying on the bearings, can still maintain free rolling motion along the pipe wall. This design effectively converts sliding friction into rolling friction, preventing scratches on the pipe wall. When the shock-absorbing wheel connecting shaft is compressed, it slides downwards along the shock-absorbing wheel positioning pins on both sides, carrying the shock-absorbing wheel with it. As the connecting shaft moves downwards, the shock-absorbing wheel spring, fitted at the bottom of the positioning pins (between the connecting shaft and the bottom support), is compressed, absorbing the rigid impact energy from the protrusion and providing flexible cushioning. After the shock-absorbing wheel rolls over the protrusion, the spring releases its elastic potential energy and rebounds, pushing the shock-absorbing wheel connecting shaft upwards, thus returning the shock-absorbing wheel to its initial outermost contact position. This structure allows the shock-absorbing wheel to undergo radial displacement along the positioning pin direction when compressed, utilizing the compression and rebound of the spring to provide flexible cushioning against protrusions on the pipe wall.

[0079] The shock-absorbing wheel of this invention not only transforms the sliding friction between the equipment and the outer wall of the pipe into rolling friction, effectively avoiding secondary damage to the pipe wall; but also its built-in spring's flexible stroke can adaptively buffer the rigid impact caused by the pipe flange connection or surface protrusions, greatly ensuring the posture stability of continuous flaw detection operations and the reliability of equipment operation.

[0080] Example 10

[0081] A modular, reconfigurable, serpentine underwater pipeline operation robot is described in Example 9, except that when performing heavy-load transport or pose adjustment operations on underwater pipelines, multiple robots are first distributed sequentially along the axial direction of the pipeline to be transported, as follows: Figure 12Each robot independently controls its joints to bend synchronously at a preset angle according to the outer diameter of the pipeline, until the end modules are precisely connected and locked together, thus forming multiple stable and rigid closed-loop fully enclosed nodes in different sections of the pipeline. Subsequently, each robot uses the thruster rotation motor to synchronously rotate the propeller thrusters arranged on both sides to the vertical upward vector direction (or the required target force direction) and start them in unison. Relying on the control system's collaborative pose calculation of the multi-robot array and the synchronous vector thrust output of the thruster group, the load-bearing capacity of the large pipeline can be evenly distributed on each enclosed node. Through this multi-point distributed thrust collaboration, the robot swarm can overcome the self-weight of the large pipeline and the resistance of complex ocean currents, and finally achieve the overall lifting, smooth lowering, and high-precision relocation and transportation of damaged or unlaid underwater pipelines, greatly expanding the operational boundaries of individual detection robots.

[0082] Vertically upward refers to the direction perpendicular to the sea level.

[0083] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A modular, reconfigurable, serpentine underwater pipeline operation robot, characterized in that, It consists of a head joint, several intermediate joints, and a tail joint connected together. Among them, multiple intermediate joints have identical structures, and the number of intermediate joints is increased or decreased according to the outer diameter of the pipe to change the overall length of the robot; the head joint, several intermediate joints, and tail joint are connected end to end and form a closed loop around the outer wall of the pipe.

2. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 1, characterized in that, The intermediate joint is formed by two modules connected by a rotating joint. One end of one module is provided with a joint connecting flange, and the other end of the other module is provided with a joint connecting groove. Each module is provided with an ultrasonic detector and a shock-absorbing wheel mechanism, which are fixedly installed on the upper part of the module. A drive mechanism is provided at the bottom of the module on one side of the joint connection groove.

3. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 2, characterized in that, A spring contact pin is provided at the center of the inner part of the joint connecting flange, and multiple locating pins are symmetrically and evenly arranged between the spring contact pin and the joint connecting flange. The joint connection groove has a pad at its center that mates with the spring contact pin, and a positioning groove that mates with the positioning pin is provided between the pad and the joint connection groove.

4. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 3, characterized in that, The drive mechanism is a propeller thruster, which includes a propeller motor, a thruster rotating shaft, a thruster rotating motor, a thruster guard, and a propeller.

5. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 4, characterized in that, The rotating joint includes a servo output flange, a servo, a servo bracket, a joint docking end plate, a friction retaining ring, a joint end cover, and a joint encapsulation end cover. The servo is mounted inside the joint encapsulation end cover via the servo bracket, and the torque output ends on both sides of the servo are fixedly connected to the servo output flange. The joint end cover is fixed to both sides of the joint docking end plate and is connected to the servo output flange via a spline, thereby converting the torque of the servo into relative deflection motion between adjacent joints. A friction retaining ring is provided between the mating surfaces of the articulated end plate and the articulated end cap.

6. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 5, characterized in that, The shock absorber mechanism includes a shock absorber, a bearing, a shock absorber positioning pin, a shock absorber connecting shaft, a shock absorber support, and a shock absorber spring; The shock absorber support is fixed to the top of the module. The shock absorber support has grooves on both sides, and shock absorber positioning pins are vertically installed in the grooves on both sides. Guide holes are opened on both shock absorber positioning pins. The two ends of the shock absorber connecting shaft are respectively sleeved through the guide holes, and shock absorber springs are sleeved on the shock absorber positioning pins. The shock absorber wheel has a circular hole at its center, and the bearing is nested and fixed inside the circular hole. The middle section of the shock absorber wheel connecting shaft passes through and is fixed to the inner ring of the bearing. The shock absorber wheel is mounted on the shock absorber wheel connecting shaft by rotating through the bearing.

7. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 6, characterized in that, The head joint has a protruding conical docking structure on its docking surface. An iron plate is fixedly embedded in the center of the front end of the conical docking structure, and an annular self-locking groove is opened on the outer periphery of the middle section of the conical docking structure. The end face of the tail joint is recessed inward to form a conical groove, the taper of which is perfectly matched with the conical docking structure of the head joint; an electromagnet is fixedly installed at the bottom of the conical groove; and four radially retractable buckles are evenly distributed along the circumference on the inner wall of the conical groove.

8. The modular, reconfigurable serpentine underwater pipeline operation robot according to claim 7, characterized in that, The tail joint is equipped with a latch drive module, which includes a latch spring, an electromagnet and a latch rotation support. Four latches are slidably mounted radially on the inner wall of the conical groove. A latch spring is provided on the back side of the latch to provide a reset thrust. A cylindrical pin is vertically provided at the bottom of each latch. The cylindrical pin extends downward and is inserted into the guide slot of the latch rotation support at the bottom. The center of the latch rotation support is fixedly connected to the torque output end of the servo motor. The buckle rotating support is a disc surface with four evenly distributed curved grooves, which respectively cooperate with the cylindrical pins at the bottom of the four buckles. During operation, the servo motor outputs torque to drive the buckle rotating support to rotate. The curved grooves on the buckle rotating support, through the action of the cam, drive the four cylindrical pins to synchronously contract inward or expand outward radially, thereby driving the buckles to overcome the buckle spring resistance and make radial linear motion, thus achieving rigid locking or release of the head joint.

9. A method for operating the modular, reconfigurable serpentine underwater pipeline operation robot as described in claim 8, characterized in that, First, based on the diameter of the pipe to be tested, each intermediate joint is controlled to bend synchronously at a preset angle, so that the head joint gradually closes towards the tail joint. During this process, the electromagnet inside the tail joint is energized to generate a magnetic field. When the iron plate at the front end of the head joint enters the magnetic attraction range, the position and angle deviation caused by underwater disturbance can be compensated by the magnetic guidance and the self-centering effect of the conical docking structure, thus guiding the tail joint and the head joint to achieve precise alignment. After alignment, the latches of the tail joint will automatically engage with the self-locking grooves of the head joint, completing a rigid mechanical lock. At this time, the electromagnet is de-energized to reduce the overall energy consumption of the system. The robot docks head to tail to form a stable closed-loop structure, achieving 360-degree full coverage and encirclement of the pipeline. After completing the encirclement, the control system rotates all propeller thrusters to the axial forward direction and starts them. The hydrodynamic force generated by the propeller thrusters provides the robot with the driving force to translate along the pipe, while simultaneously generating an inward pressure force to move along the pipe. During movement, ultrasonic detectors are triggered to perform continuous non-destructive testing on the pipe. During operation, the shock-absorbing wheels transmit the radial impact force they receive to the internal shock-absorbing wheel connecting shaft through the bearings. During this shock absorption and yielding process, the shock-absorbing wheels can still maintain a free rolling motion along the pipe wall thanks to the bearings, effectively converting sliding friction into rolling friction. After being compressed, the shock-absorbing wheel connecting shaft, along with the shock-absorbing wheels, slides downward in a straight line along the shock-absorbing wheel positioning pins on both sides. As the shock-absorbing wheel connecting shaft moves downward, the shock-absorbing wheel springs fitted at the bottom of the shock-absorbing wheel positioning pins are compressed, absorbing the rigid impact energy from the protrusions and achieving flexible buffering. When the shock-absorbing wheel rolls past the protrusion, the spring releases its elastic potential energy and rebounds, pushing the shock-absorbing wheel connecting shaft upward, thereby driving the shock-absorbing wheel back to its initial outermost contact position.

10. The working method of the modular reconfigurable serpentine underwater pipeline operation robot according to claim 9, characterized in that, When performing heavy-load handling or orientation adjustment operations on underwater pipelines, multiple robots are first distributed sequentially along the axis of the pipeline to be transported. Each robot independently controls its joints to bend synchronously at a preset angle according to the outer diameter of the pipeline, until the end modules are precisely connected and locked together, thus forming multiple stable and rigid closed-loop fully enclosed nodes in different sections of the pipeline. Subsequently, each robot uses a thruster to rotate the propeller thrusters arranged on both sides to rotate synchronously to the vertical upward vector direction and start them in unison. Through multi-point distributed thrust coordination, the robot swarm can overcome the self-weight of large pipelines and complex ocean current resistance, and finally achieve the overall lifting, smooth lowering, and relocation of damaged or unlaid underwater pipelines, greatly expanding the operational boundaries of individual detection robots.

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