Multi-section variable diameter nuclear power pipeline inspection robot and control method thereof

Abstract

The application belongs to the technical field of pipeline internal inspection robots, and aims to solve the problems that traditional pipeline robots are difficult to adapt to complex pipeline environment and lack of variable diameter function, discloses a multi-section variable diameter nuclear power pipeline inspection robot and a control method thereof, the robot comprises a first crawling module, a second crawling module and a third crawling module connected in sequence along an axial direction, the crawling modules all comprise a variable diameter track driving mechanism and are configured to be synchronously expanded or contracted through motor driving of a plurality of track wheels, two adjacent crawling modules are flexibly connected and are provided with a rigid connecting rod mechanism, a suspension telescopic detection assembly is integrated in the second crawling module, and an electric wire twisting device is provided, so that a detection camera is controlled to be extended or retracted along a direction perpendicular to the advancing direction of the robot, and the method realizes multi-section variable diameter nuclear power pipeline inspection by using the robot. The application can realize a large variable diameter effect, and realize the passing performance in complex environments such as passing through a bend and passing through a ridge.

Description

Technical Field

[0001] This application belongs to the field of pipeline internal inspection robot technology, and in particular relates to a multi-section variable diameter nuclear power pipeline inspection robot and its control method. Background Technology

[0002] Currently, pipeline inspection robot technologies typically include helical drive and wheeled drive solutions. Helical drive solutions utilize a helical drive structure, usually controlled by a motor to move within the pipeline. Combined with sensors and endoscopes, they enable the inspection of the pipeline environment. This approach is generally suitable for relatively simple pipeline environments without significant blockages, such as straight or regularly curved pipelines. Wheeled drive solutions use motors to drive wheels, propelling the robot forward. These include four-wheeled pipeline robots resembling small vehicles and variable-diameter wheeled robots.

[0003] However, the above two solutions are suitable for scenarios with simple pipeline environments and small diameter variation ranges. The helical drive design allows for high movement speeds within the pipeline, but its rigid structure has poor adaptability and makes it difficult to overcome obstacles and hurdles within the pipeline. The wheel drive design can adapt to changes in pipe diameter, but it cannot meet the requirements for cornering and overcoming obstacles. Summary of the Invention

[0004] The purpose of this application is to provide a multi-section variable diameter nuclear power pipeline inspection robot and its control method, which solves the problems that traditional pipeline robots are difficult to adapt to complex pipeline environments and lack variable diameter functions.

[0005] To achieve the above objectives, this application provides the following technical solution: In one aspect, this application provides a multi-section variable-diameter nuclear power pipeline inspection robot, including a first crawling module, a second crawling module and a third crawling module connected sequentially along the axial direction; The first crawling module, the second crawling module, and the third crawling module all include a variable diameter track drive mechanism. The variable diameter track drive mechanism is configured to drive multiple track wheels to expand or retract synchronously via a motor, so as to adapt to the inner wall of pipes with different diameters. Two adjacent crawling modules are connected by a flexible connector and are equipped with a rigid linkage mechanism. The rigid linkage mechanism includes a push rod assembly located at the tail of the preceding crawling module and a docking interface located at the head of the following crawling module. The end of the push rod assembly is provided with a ball joint, which can extend and cooperate with the docking interface to rigidly connect the two adjacent crawling modules into a whole. The second crawling module integrates a suspended telescopic detection component, which includes an electric stranding device and a detection camera. The electric stranding device is configured to control the detection camera to extend or retract in a direction perpendicular to the robot's travel direction. The detection camera is used to detect the pipeline environment.

[0006] As one feasible approach, the variable diameter track drive mechanism includes a stepper motor, a lead screw, a slider, a boom link, and a timing disc; The stepper motor is connected to the lead screw drive, and the slider is sleeved on the lead screw and moves axially as the lead screw rotates; One end of the outrigger link is hinged to the slider, and the other end is connected to the track wheel; The synchronous disc connects the three support arm links, so that when the stepper motor drives the lead screw to rotate, the slider pulls the three support arm links to move synchronously, thereby realizing the synchronous deployment or retraction of the three track wheels.

[0007] As one feasible approach, the push rod assembly includes a push rod motor and a push rod body; The push rod motor is configured to drive the push rod body to perform linear reciprocating motion; The ball joint is located at the free end of the push rod body, and the docking interface is a groove or snap-fit ​​structure that is adapted to the ball joint, so that in the rigid connection state, the adjacent crawling modules can transmit thrust and maintain a certain angular adaptability.

[0008] As an feasible approach, the front end of the first crawling module is also equipped with a main detection camera to capture the travel path and inner wall conditions in front of the pipe. The electric cable winding device inside the second crawling module includes a drum and a drive motor. The detection camera is wound onto the drum via a cable. The drive motor is configured to control the drum to rotate forward to release the cable and allow the detection camera to droop, or to rotate backward to retract the cable and store the detection camera inside the second crawling module.

[0009] As one feasible approach, the robot also includes a cable reel assembly, which comprises a cable frame, an auxiliary cable reeling mechanism, a braking mechanism, and a meter encoder. The wire frame is equipped with wheels and a telescopic pull rod; The auxiliary cable winding mechanism is configured to assist in reeling in and unwinding the main cable connecting the robot during its movement. The meter encoder contacts the main cable and is used to measure and output the position and distance information of the detection camera relative to the robot body in real time.

[0010] Secondly, this application also provides a control method for a multi-section variable-diameter nuclear power pipeline inspection robot, including a threshold crossing control mode, the steps of which include: S1: Control the variable-diameter track drive mechanism of the first crawling module, the second crawling module, and the third crawling module to retract synchronously, thereby reducing the overall outer diameter of the robot; S2: Control the extension of the push rod assembly of each module, so that the first crawling module and the second crawling module, and the second crawling module and the third crawling module are rigidly connected through ball joints and docking interfaces to form an integral structure; S3: Control the first crawling module to move forward until it passes the middle position of the pipe tee or obstacle; S4: Control the push rod assembly of the second crawling module to continue pushing the first crawling module forward, while the second crawling module moves on its own until the second crawling module passes the middle position of the obstacle; S5: Control the push rod assembly of the third crawling module to push the second crawling module forward, while the third crawling module moves on its own until all modules have completely crossed the obstacle; S6: Control the retraction of the push rod assemblies of each module, release the rigid connection, restore the flexible connection state, and the three crawling modules crawl forward synchronously.

[0011] As an implementable approach, the method also includes a diameter switching control mode, which performs the following operations when the robot moves from a large-diameter region to a small-diameter region: The stepper motor inside each crawling module drives the lead screw to rotate, which in turn drives the slider to pull the support arm connecting rod, causing the track wheel to retract inward until the outer diameter of the track is less than or equal to the inner diameter of the small pipe area. When the robot moves from a small-diameter pipe area to a large-diameter pipe area, perform the following operations: The stepper motor inside each crawling module drives the lead screw to rotate in the opposite direction, which drives the slider to push the support arm connecting rod, causing the track wheel to unfold outward until the outer edge of the track is tightly fitted with the inner wall of the large-diameter area.

[0012] As an implementable approach, the method also includes a cornering control mode, the steps of which include: The push rod assemblies of each control module retract, so that adjacent crawling modules are connected only by flexible connectors; The speed of the first crawling module is controlled to be greater than the speed of the second crawling module, and the speed of the second crawling module is greater than or equal to the speed of the third crawling module. During the movement, the adaptive function of the outrigger of the variable diameter track drive mechanism is used to adjust the retraction angle of the track wheels of each module to fit the inner wall of the bend, keeping the flexible connector in an extended state and preventing the rear module from squeezing the front module.

[0013] As an implementable approach, the method also includes a tee branch detection and control mode, the steps of which include: When the robot moves to the T-junction, control the robot to stop moving; Start the electric stranding device in the second crawling module, control the drum to rotate forward, release the cable so that the detection camera hangs down along the vertical direction of the T-shaped branch pipe and enters the inside of the branch pipe; The detection camera collects video information of the inner wall of the branch pipe, and the depth of the detection camera into the branch pipe is recorded in real time by the meter encoder; After the test is completed, the electric stranding device is reversed, and the cable is retracted to completely store the test camera inside the second crawling module. Restart the obstacle crossing control mode or normal travel mode to allow the robot to pass through the three-way area.

[0014] As an implementable approach, the method also includes a vertical climb control mode when the robot is working inside a vertical pipe: The stepper motor drives the lead screw of each crawling module to push the slider to open the extension arm connecting rod, so that the track wheel is tightly pressed against the inner wall of the pipe; The robot's own weight is supported by the friction generated between the rubber tracks and the inner wall of the pipe. The drive motors of the three crawling modules are controlled to operate synchronously, driving the robot to move up or down along the vertical pipe.

[0015] Compared with existing technologies, the multi-section variable-diameter nuclear power plant pipeline inspection robot and its control method provided in this application have the following advantages: This application utilizes a multi-section diameter-changing mechanism design to achieve a significant diameter-changing effect. By combining rigid and flexible linkages, the robot possesses both rigidity and flexibility, realizing the flexible characteristics of a rigid robot and greatly improving its adaptability in complex pipelines. This application effectively solves the problems of traditional pipeline robots' difficulty in adapting to complex pipeline environments and their lack of diameter-changing functionality. Complex pipeline environments are characterized by complex pipeline geometry, numerous obstacles, and harsh working conditions; the lack of diameter-changing functionality refers to the robot's limited ability to adjust its outer diameter according to the pipeline's inner diameter.

[0016] This application designs a control method for the robot, enabling it to navigate complex environments such as curves and obstacles.

[0017] This application addresses the problems of traditional pipeline robots' inability to adapt to complex pipeline environments and their lack of variable diameter functionality. Through the design of a variable diameter track module, it can achieve adaptability to a wide range of pipe diameter changes. The combination of multi-section design and control methods enables the robot to navigate complex pipeline environments such as bends and T-shaped pipes.

[0018] Furthermore, the design of mounting a cable reel camera on the robot's intermediate crawler in this application makes it easier for the robot to inspect the T-junction branch pipe and greatly improves the inspection efficiency.

[0019] Furthermore, this application employs a combined design of rigid and flexible links, significantly improving the robot's adaptability within pipelines. This not only solves the problem of poor adaptability of robots within pipelines but also opens up new avenues for research on robots for inspecting complex pipelines. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0021] Figure 1 An overall structural diagram of the multi-section variable-diameter nuclear power pipeline inspection robot provided in this application; Figure 2 This is a schematic diagram of the structure of the variable diameter track drive mechanism provided in this application; Figure 3 A schematic diagram of the push rod function provided in this application; Figure 4 The crawler obstacle crossing simulation provided in this application Figure 1 ; Figure 5 The crawler obstacle crossing simulation provided in this application Figure 2 ; Figure 6 The crawler obstacle crossing simulation provided in this application Figure 3 ; Figure 7 The crawler obstacle crossing simulation provided in this application Figure 4 ; Figure 8 The variable diameter simulation diagram provided for this application; Figure 9 The vertical climbing attitude simulation diagram provided for this application; Figure 10 The cornering posture simulation diagram provided for this application; Figure 11 This is a schematic diagram of the cable reel camera inspection provided in this application; Figure 12 This application provides a schematic diagram of the cable retraction camera. Figure 13 A flowchart illustrating the control method for the multi-section variable-diameter nuclear power pipeline inspection robot provided in this application.

[0022] Explanation of reference numerals in the attached figures: 1. First crawling module; 2. Second crawling module; 3. Third crawling module; 4. Variable diameter track drive mechanism; 5. Track wheel; 6. Lead screw; 7. Support arm connecting rod; 8. Synchronizing disc; 9. Sleeve; 10. Detection camera; 11. Wire frame; 12. Auxiliary wire winding mechanism; 13. Braking mechanism; 14. Ball joint; 15. Push rod assembly; 16. Main detection camera; 17. Support rod slider proximity switch; 18. Telescopic rod limit proximity switch; 19. Rearview lens; 20. Track lifting and lowering drive motor; 21. Telescopic rod motor. Detailed Implementation

[0023] The following detailed description provides further details on specific implementation methods.

[0024] like Figures 1 to 12 As shown, this application provides a multi-section variable-diameter nuclear power pipeline inspection robot, comprising a first crawling module 1, a second crawling module 2, and a third crawling module 3 connected in series along the axial direction. The three crawling modules are structurally similar, each equipped with an independent variable-diameter track drive mechanism 4, but each has a different functional focus: the first crawling module 1, located at the foremost end, not only provides the drive function but also carries a main detection camera 16 for observing the road conditions ahead and a push rod assembly 15 for driving the rigid linkage mechanism; the second crawling module 2, located in the middle, integrates a suspended telescopic detection assembly, mainly used for specialized inspection of tee branch pipes; the third crawling module 3, located at the rear, mainly provides the rear driving force and the docking foundation for rigid connection. Each crawling module uses an internal motor to drive three circumferentially distributed track wheels 5 to synchronously extend or retract, thereby achieving adaptive capability to pipes of different diameters.

[0025] Adjacent crawling modules are connected by flexible connectors and equipped with rigid linkage mechanisms. Specifically, the first crawling module 1 and the second crawling module 2 are connected by flexible connectors, and the second crawling module 2 and the third crawling module 3 are connected by flexible connectors. The flexible connectors are existing technologies, such as flexible cables, steel wire ropes, and elastic hinges, enabling bending and deflection between adjacent modules, giving the robot flexible bending capabilities. Simultaneously, the rigid linkage mechanism is used to rigidly connect multiple modules into a whole when crossing obstacles, improving passability. The rigid linkage mechanism includes a push rod assembly 15 located at the tail of the preceding crawling module and a docking interface located at the head of the following crawling module. The end of the push rod assembly 15 has a ball joint 14 that can extend and mate with the docking interface, rigidly connecting the two adjacent crawling modules into a whole.

[0026] The variable-diameter track drive mechanism 4 is configured to drive multiple track wheels 5 to simultaneously extend or retract via a motor, adapting to the inner wall of pipes with different diameters. For example... Figure 2 As shown, the variable diameter track drive mechanism 4 includes a stepper motor, a lead screw 6, a slider, support arm connecting rods 7, and a timing disk 8. The stepper motor is connected to the lead screw 6 via a transmission. The slider is sleeved on the lead screw 6 and moves axially as the lead screw 6 rotates. One end of the support arm connecting rod 7 is hinged to the slider, and the other end is connected to the track wheel 5. The timing disk 8 connects the three support arm connecting rods 7, so that when the stepper motor drives the lead screw 6 to rotate, the slider pulls the three support arm connecting rods 7 to move synchronously, thereby realizing the synchronous deployment or retraction of the three track wheels 5.

[0027] The stepper motor includes a telescopic rod motor 21 and a track lifting and lowering drive motor 20. The telescopic rod motor 21 is responsible for controlling the longitudinal extension and retraction of the robot, and the track lifting and lowering drive motor 20 is responsible for controlling the lifting and lowering of the track, thereby controlling the change of the robot's outer diameter.

[0028] Optionally, the push rod assembly 15 is a telescopic rod. The telescopic rod is used to change the longitudinal dimension of the robot, while the telescopic pull rod on the wire frame 11 is a radially adjustable brake mechanism 13.

[0029] like Figure 2 As shown, the variable diameter track drive mechanism 4 is equipped with a support rod slider proximity switch 17, a telescopic rod limit proximity switch 18, a rearview camera 19, a telescopic rod, track lifting and lowering drive motor 20, and a telescopic rod motor 21.

[0030] The front end of the first crawling module 1 is equipped with a main detection camera 16, which is used to capture the travel path and inner wall condition of the pipeline.

[0031] The electric cable winding device inside the second crawling module 2 includes a drum and a drive motor. The detection camera 10 is wound around the drum 9 via a cable. The drive motor is configured to control the drum 9 to rotate forward to release the cable and cause the detection camera 10 to droop, or to rotate in reverse to retract the cable and store the detection camera 10 inside the second crawling module 2.

[0032] The robot is also equipped with a cable reel device, which includes a cable frame 11, an auxiliary cable reeling mechanism 12, a braking mechanism 13, and a meter encoder. The cable frame 11 is equipped with wheels and a telescopic rod. The auxiliary cable reeling mechanism 12 is configured to assist in reeling in and unreeling the main cable connecting to the robot during its movement. The meter encoder is in contact with the main cable and is used to measure and output the position and distance information of the detection camera relative to the robot body in real time.

[0033] The cable reel device is installed on the tail housing of the last crawling module (third crawling module 3) of the robot. The auxiliary cable reel mechanism 12 is used to synchronously reel in and out the main cable when the robot moves. The brake mechanism 13 is installed on the cable frame 11 of the cable reel device and is arranged coaxially with the rotating shaft of the auxiliary cable reel mechanism 12. It is used to lock the rotation of the cable reel when the robot stops moving.

[0034] The specific working principle of the variable diameter track drive mechanism 4 is as follows: Inside each crawling module, there is a stepper motor, the output shaft of which is connected to a lead screw 6. A slider is mounted on the lead screw 6. When the stepper motor rotates, it drives the lead screw 6 to rotate, thereby driving the slider to move linearly along the lead screw axis. One end of the support arm connecting rod 7 is hinged to the slider, and the other end is equipped with a track wheel 5. To achieve synchronous movement of the three track wheels 5, a synchronization disc is used to connect the support arm connecting rods 7 corresponding to the three tracks. Based on the force transmission characteristics, when the stepper motor drives the lead screw 6 to rotate, the slider is pulled. Through the action of the synchronization disc, the angles of the three support arm connecting rods 7 change simultaneously, thereby driving the three track wheels 5 to synchronously retract inward or extend outward. This design ensures that the robot maintains a stable center of gravity and uniform contact force between the track and the pipe wall when adapting to different pipe diameters.

[0035] To cope with the complex interface environments such as tees and crosses commonly found in nuclear power plant pipelines, the robot was designed with a unique rigid linkage connection mechanism. For example... Figure 3 The schematic diagram of the push rod function shows that when the robot needs to pass over a "bump" at the pipe interface, the push rod assembly 15 located at the rear of the preceding module begins to operate. The push rod assembly 15 includes a push rod motor and a push rod body. The rotation of the push rod motor drives the push rod body to perform linear motion. The head of the push rod body is designed as a ball joint 14, and the head of the following module has a matching docking interface. When the push rod extends, the ball joint 14 inserts into the docking interface, rigidly locking the two modules, originally connected by a flexible cable, into a single unit. This ball joint design not only ensures the stability of the connection and prevents loosening, but also allows for slight angular deflections between the modules, accommodating possible irregular deformations of the pipe.

[0036] The push rod assembly 15 includes a push rod motor and a push rod body. The push rod motor is configured to drive the push rod body to perform linear reciprocating motion. The push rod motor is fixedly mounted on the tail end cap of the robot's single-section crawling module and connected to the lead screw 6; the push rod body is coaxially arranged in the central channel of the crawling module, and its tail is connected to the lead screw 6.

[0037] The ball joint 14 is located at the free end of the push rod body, and the docking interface is a groove or snap-fit ​​structure that is adapted to the ball joint 14, so that in the rigid connection state, the adjacent crawling modules can transmit thrust and maintain a certain angle adaptability.

[0038] The robot's process of crossing the obstacle is as follows Figures 4 to 7 As shown, a segmented cooperative motion strategy is adopted. (As...) Figure 4 As shown, the three crawler sets retract their tracks in advance to reduce the outer diameter, while all the push rods between the modules extend, rigidly connecting the three modules into a long unit. Then, as... Figure 5As shown, the first crawling module 1 starts first, crawling over the middle suspended position of the T-junction. At this time, due to the rigid connection, the second crawling module 2 in the middle pushes the first crawling module 1 forward through its push rod, assisting it to completely overcome the obstacle. Subsequently, as... Figure 6 As shown, when the second crawling module 2 reaches the middle position of the T-junction, the final third crawling module 3 uses its push rod to propel the second crawling module 2 forward to overcome the obstacle. Finally, as... Figure 7 As shown, once all modules have approached or passed the obstacle, the push rod retracts to release the rigid connection, and the three crawling modules resume synchronous crawling mode, successfully passing through the three-way area. This "contraction-rigid connection-segmented push-recovery" strategy effectively solves the problem of traditional robots easily getting stuck or falling when there are too large gaps.

[0039] When the robot reaches the pipe diameter change point, its diameter-changing function comes into play, such as... Figure 8 As shown. When moving from a large-diameter pipe to a small-diameter pipe, the sliders on the lead screws 6 inside the three sets of crawlers pull the support arms backward, retracting the lifting arms sequentially until the overall diameter is reduced to a size suitable for the small-diameter pipe before continuing to crawl. Conversely, when switching from a small-diameter pipe to a large-diameter pipe, the motor drives the sliders to push the support arms forward, unfolding the lifting arms until the tracks are once again in close contact with the enlarged pipe wall. This process can be manually controlled or automatically executed based on sensor feedback, ensuring the robot's smooth passage through the variable-diameter tee, and its obstacle-crossing logic is similar to that of a straight-pipe tee.

[0040] In vertical piping environments, such as Figure 9 As shown, the robot demonstrates excellent vertical climbing ability. The crawler's motor drives the lead screw 6 to forcefully open and lift the slider, pressing the rubber track tightly against the inner wall of the pipe. At this point, a huge static friction force is generated between the track and the pipe wall, sufficient to overcome the robot's own weight. Supported by this friction force, the drive motor rotates the track, enabling the robot to stably ascend or descend within the vertical pipe without slipping.

[0041] For pipe bending environments, such as Figure 10 As shown, the robot employs a flexible cornering strategy. At this time, the rigid push rods between modules are in the retracted state, and the modules are connected only by flexible cables. During cornering, the control system adjusts the speed of each module, ensuring that the first crawling module 1 in front moves slightly faster than the modules behind, keeping the flexible connecting rods taut and extended to prevent rear modules from piling up and squeezing the front modules. Simultaneously, utilizing the adaptive function of the outriggers, the track wheels 5 of each module automatically adjust their retraction angle to best conform to the inner wall of the bend, smoothly navigating the curve sequentially.

[0042] For the inspection requirements of the T-junction branch pipe, this application designs a suspended telescopic inspection component in the second crawling module 2, including an electric stranding device and an inspection camera 10. The electric stranding device is configured to control the inspection camera 10 to extend or retract in a direction perpendicular to the robot's travel direction. Figure 11 and Figure 12 As shown. When the robot reaches the T-junction position, it stops moving. The electric winch device built into the second crawling module 2 starts, controlling the drum to rotate forward and slowly lowering the cable with the camera lens at the end. The lens hangs vertically into the branch pipe, performing a comprehensive video inspection of the inner wall of the branch pipe. At the same time, the meter encoder on the external cable reel works in real time, accurately recording the distance the lens has descended, helping the operator to locate the defect. After the vertical hole inspection is completed, as... Figure 12 As shown, the cable reversing device reverses to retract the cable, completely retrieving the lens back into the second crawling module 2. The robot can then smoothly pass through the three-way area following the aforementioned obstacle-crossing procedure. Furthermore, the accompanying cable reel device features reciprocating cable winding and braking functions, effectively preventing cable tangling and knots caused by long-distance dragging. The wheels and telescopic rods on the cable frame greatly facilitate on-site movement and storage of the equipment, saving time and effort.

[0043] It should be noted that the electric cable winding device is existing technology. It is fixedly installed in the tail housing of the second crawling module 2. The cable winding and unwinding are achieved by driving the winch wheel with a motor, so as to control the extension and retraction of the front-end detection camera.

[0044] The sleeve 9 is coaxially mounted on the central axis of the second crawling module 2 to provide guidance and protection for the cable of the electric stranding device and limit the radial displacement of the cable.

[0045] like Figure 13 As shown, this application also provides a control method for a multi-section variable-diameter nuclear power pipeline inspection robot. Based on the structure of the robot, the method includes a threshold-crossing control mode, the steps of which include: S1: Control the variable-diameter track drive mechanism 4 of the first crawling module 1, the second crawling module 2, and the third crawling module 3 to retract synchronously, thereby reducing the overall outer diameter of the robot; S2: Control the extension of the push rod assembly 15 of each module, so that the first crawling module 1 and the second crawling module 2, and the second crawling module 2 and the third crawling module 3 are rigidly connected to the docking interface through the ball joint 14 to form an integral structure; S3: Control the first crawling module 1 to move forward until it passes the middle position of the pipe tee or obstacle; S4: Control the push rod assembly 15 of the second crawling module 2 to continue pushing the first crawling module 1 forward, while the second crawling module 2 moves on its own until the second crawling module 2 passes the middle position of the obstacle; S5: Control the push rod assembly 15 of the third crawling module 3 to push the second crawling module 2 forward, while the third crawling module 3 moves on its own until all modules have completely crossed the obstacle; S6: Control the push rod assembly 15 of each module to retract, release the rigid connection, restore the flexible connection state, and the three crawling modules 3 crawl forward synchronously.

[0046] In one embodiment, the method further includes a variable-diameter switching control mode, specifically: (1) When the robot moves from a large-diameter area to a small-diameter area, perform the following operations: The stepper motor inside each crawling module drives the lead screw 6 to rotate, which in turn drives the slider to pull the support arm connecting rod 7, causing the track wheel 5 to retract inward until the outer diameter of the track is less than or equal to the inner diameter of the small pipe area. (2) When the robot moves from a small-diameter area to a large-diameter area, perform the following operations: The stepper motor inside each crawling module drives the lead screw 6 to rotate in the opposite direction, which drives the slider to push the support arm connecting rod 7, causing the track wheel 5 to unfold outward until the outer edge of the track is tightly fitted to the inner wall of the large diameter area.

[0047] In one embodiment, the method further includes a cornering control mode, the steps of which include: (1) Control the retraction of the push rod assembly 15 of each module so that adjacent crawling modules are connected only by flexible connectors; (2) Control the speed of the first crawling module 1 to be greater than the speed of the second crawling module 2, and the speed of the second crawling module 2 to be greater than or equal to the speed of the third crawling module 3; (3) During the journey, the adaptive function of the outrigger of the variable diameter track drive mechanism 4 is used to adjust the contraction angle of the track wheel 5 of each module to fit the inner wall of the bend, keep the flexible connector in the extended state, and prevent the rear module from squeezing the front module.

[0048] In one embodiment, the method further includes a tee branch detection and control mode, the steps of which include: (1) When the robot moves to the position of the T-junction pipe, control the robot to stop moving; (2) Start the electric stranding device in the second crawling module 2, control the drum to rotate forward, release the cable so that the detection camera 10 hangs down along the vertical direction of the three-way branch pipe and enters the inside of the branch pipe; (3) The detection camera 10 collects video information of the inner wall of the branch pipe, and the depth of the detection camera 10 into the branch pipe is recorded in real time by the meter encoder; (4) After the test is completed, control the electric stranding device to reverse and retract the cable to completely store the test camera 10 inside the second crawling module 2; (5) Restart the obstacle crossing control mode or normal travel mode to allow the robot to pass through the three-way area.

[0049] In one embodiment, the method further includes a vertical climb control mode, which performs the following steps when the robot is working inside a vertical pipe: (1) Control the stepper motor drive screw 6 of each crawling module to push the slider to open the arm connecting rod 7, so that the track wheel 5 is tightly pressed against the inner wall of the pipe; (2) The robot’s weight is supported by the friction between the rubber track and the inner wall of the pipe; (3) Control the drive motors of the three crawling modules to run synchronously, so that the robot can move up or down along the vertical pipe.

[0050] In the experimental verification of nuclear power pipelines, this application successfully achieved precise detection of large-diameter changes, bends, ridges, and tee branches, meeting the stringent requirements for inspection and maintenance of complex pipelines in high-radiation environments.

[0051] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A multi-section variable-diameter nuclear power plant pipeline inspection robot, characterized in that, The system includes a first crawling module, a second crawling module, and a third crawling module connected sequentially along the axial direction. Each of the three crawling modules includes a variable-diameter track drive mechanism, which is configured to drive multiple track wheels to expand or retract synchronously via a motor to adapt to the inner walls of pipes with different diameters. Adjacent crawling modules are flexibly connected and equipped with a rigid linkage mechanism, which includes a push rod assembly located at the tail of the preceding crawling module and a docking interface located at the head of the following crawling module. The second crawling module integrates a suspended telescopic detection component, which includes an electric stranding device and a detection camera. The electric stranding device is configured to control the detection camera to extend or retract in a direction perpendicular to the robot's travel direction.

2. The multi-section variable-diameter nuclear power pipeline inspection robot according to claim 1, characterized in that, The variable diameter track drive mechanism includes a stepper motor, a lead screw, a slider, a support arm connecting rod, and a timing disc. The stepper motor is connected to the lead screw via a transmission. The slider is sleeved on the lead screw and moves axially as the lead screw rotates. One end of the support arm connecting rod is hinged to the slider, and the other end is connected to a track wheel. The timing disc connects the three support arm connecting rods, so that when the stepper motor drives the lead screw to rotate, the slider pulls the three support arm connecting rods to move synchronously, thereby realizing the synchronous deployment or retraction of the three track wheels.

3. The multi-section variable-diameter nuclear power pipeline inspection robot according to claim 1, characterized in that, The push rod assembly has a push rod motor and a push rod body. The end of the push rod assembly is provided with a ball joint and mates with the docking interface. The push rod motor is configured to drive the push rod body to perform linear reciprocating motion. The ball joint is located at the free end of the push rod body. The docking interface is a groove or snap-fit ​​structure adapted to the ball joint, so that in a rigid connection state, the push force can be transmitted between adjacent crawling modules and a certain angular adaptability can be maintained.

4. The multi-section variable-diameter nuclear power pipeline inspection robot according to claim 1, characterized in that, The front end of the first crawling module is equipped with a main detection camera. The electric stranding device includes a drum and a drive motor. The detection camera is wound around the drum via a cable. The drive motor is configured to control the drum to rotate forward to release the cable and cause the detection camera to droop, or to rotate in reverse to retract the cable and store the detection camera inside the second crawling module.

5. The multi-section variable-diameter nuclear power pipeline inspection robot according to claim 1, characterized in that, It also includes a cable reel device, which includes a cable frame, an auxiliary cable reeling mechanism, a braking mechanism, and a meter encoder. The cable frame is equipped with wheels and a telescopic rod. The auxiliary cable reeling mechanism is configured to assist in reeling in and out the main cable connecting the robot during the robot's movement. The meter encoder is in contact with the main cable and is used to measure and output the position and distance information of the detection camera relative to the robot body in real time.

6. A control method for a multi-section variable-diameter nuclear power plant pipeline inspection robot, characterized in that, include: S1: Control the variable-diameter track drive mechanism of the first crawling module, the second crawling module, and the third crawling module to retract synchronously, thereby reducing the overall outer diameter of the robot; S2: Control the extension of the push rod assembly of each module, so that the first crawling module and the second crawling module, and the second crawling module and the third crawling module are rigidly connected through ball joints and docking interfaces to form an integral structure; S3: Control the first crawling module to move forward until it passes the middle position of the pipe tee or obstacle; S4: Control the push rod assembly of the second crawling module to continue pushing the first crawling module forward, while the second crawling module moves on its own until the second crawling module passes the middle position of the obstacle; S5: Control the push rod assembly of the third crawling module to push the second crawling module forward, while the third crawling module moves on its own until all modules have completely crossed the obstacle; S6: Control the retraction of the push rod assemblies of each module, release the rigid connection, restore the flexible connection state, and the three crawling modules crawl forward synchronously.

7. The control method for the multi-section variable-diameter nuclear power pipeline inspection robot according to claim 6, characterized in that, It has a variable diameter switching control mode. When the robot enters the small diameter area from the large diameter area, it controls the stepper motor inside each crawling module to drive the lead screw to rotate, which drives the slider to pull the support arm link, causing the track wheel to retract inward until the outer diameter of the track is less than or equal to the inner diameter of the small diameter area. When the robot moves from the small-diameter pipe area to the large-diameter pipe area, the stepper motor inside each crawling module drives the lead screw to rotate in the opposite direction, which drives the slider to push the support arm linkage, causing the track wheel to unfold outward until the outer edge of the track is tightly fitted with the inner wall of the large-diameter pipe area.

8. The control method for the multi-section variable-diameter nuclear power pipeline inspection robot according to claim 6, characterized in that, It has a cornering control mode, the steps of which include: The push rod assemblies of each control module retract, so that adjacent crawling modules are connected only by flexible connectors; The speed of the first crawling module is controlled to be greater than the speed of the second crawling module, and the speed of the second crawling module is greater than or equal to the speed of the third crawling module. During the movement, the outriggers of the variable diameter track drive mechanism are used to adjust the retraction angle of the track wheels of each module to fit the inner wall of the bend, keeping the flexible connector in an extended state and preventing the rear module from squeezing the front module.

9. The control method for the multi-section variable diameter nuclear power pipeline inspection robot according to claim 6, characterized in that, It has a three-way branch pipe detection and control mode, and the steps include: When the robot moves to the T-junction, control the robot to stop moving; Start the electric stranding device in the second crawling module, control the drum to rotate forward, release the cable so that the detection camera hangs down along the vertical direction of the T-shaped branch pipe and enters the inside of the branch pipe; The detection camera collects video information of the inner wall of the branch pipe, and the depth of the detection camera into the branch pipe is recorded in real time by the meter encoder; After the test is completed, the electric stranding device is reversed, and the cable is retracted to completely store the test camera inside the second crawling module. Restart the obstacle crossing control mode or normal travel mode to allow the robot to pass through the three-way area.

10. The control method for the multi-section variable-diameter nuclear power pipeline inspection robot according to claim 6, characterized in that, It features a vertical climbing control mode. When the robot is working inside a vertical pipe, the stepper motors of each crawling module drive the lead screws to push the sliders to open the arm linkages, so that the track wheels are pressed tightly against the inner wall of the pipe. The friction generated between the rubber track and the inner wall of the pipe supports the robot's own weight. The drive motors of the three crawling modules are controlled to run synchronously, driving the robot to move up or down along the vertical pipe.

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