A statically indeterminate centering and constant preload internal inspection robot for large-diameter heavy-duty pipelines

Abstract

This invention discloses a statically indeterminate, centering, and constant preload internal inspection robot for large-diameter, heavy-duty pipelines, comprising: a traction system, including a central chamber, a main shaft, deformation supports, a drive wheel, and a drive module; several sets of deformation supports are provided; the main shaft passes through the central chamber; several sets of deformation supports are circumferentially and evenly spaced on the outer walls at both ends of the main shaft; a central slider is slidably connected to the main shaft; the deformation supports are hinged to the central slider; and a preload spring is provided between the central slider and the central chamber; a detection system is mounted on the drive wheel; a power supply system is hinged to the end of the main shaft; and a control system is mounted on the main shaft. This invention fundamentally improves upon the problems of eccentricity failure and traction instability in large-diameter, heavy-duty internal inspection robots, exhibiting extremely high centering accuracy and obstacle-crossing capability.

Description

Technical Field

[0001] This invention relates to the field of equipment technology for internal inspection of oil and gas pipelines, and in particular to an internal inspection robot for large-diameter, heavy-duty pipelines with ultra-static indeterminate centering and constant pre-tightening. Background Technology

[0002] Long-distance natural gas pipelines are a vital infrastructure for national energy transportation, and regular non-destructive testing of the circumferential welds inside the pipelines is a core means of ensuring their safe operation. With the growth of energy demand, natural gas trunk lines are developing towards larger diameters (such as DN1016) and higher pressures. This requires internal inspection robots to be equipped with a massive array of non-destructive testing sensors, high-capacity power batteries, and data processing units, resulting in a sharp increase in the robot's overall weight and putting it into a "heavy-load" operation mode.

[0003] Existing pipe inspection robots typically employ adaptive diameter-adjusting mechanisms to travel close to the pipe wall. The mainstream technical solution involves independently configuring a pre-tensioning spring on each support wheel arm in the robot's circumferential direction, utilizing the linear elastic force of the springs to press the support wheel firmly against the pipe wall. However, this traditionally considered "mature" technical solution reveals the following serious physical limitations when facing heavy-duty, 1-meter-wide pipe inspection conditions: First, there is the problem of severe eccentricity in the robot body caused by gravity-induced uneven loading. Under heavy-load conditions with large diameters, the gravity vector generated by the robot's own weight is much greater than the preload of a single spring. Because the springs of each wheel arm in a traditional structure work independently, the spring at the bottom of the robot is overcompressed due to its enormous weight, while the spring at the top is undercompressed. This uneven force and deformation of the springs directly causes the robot's geometric center axis to deviate significantly from the centerline of the pipe. This eccentricity not only causes inconsistencies in the lift-off values ​​of the sensor probes, severely impairing detection accuracy, but also easily leads to excessive wear on the bottom wheel system.

[0004] Second, there is the risk of jamming and slippage due to drastic fluctuations in radial support force. According to Hooke's Law, the spring force output by a spring is proportional to its compression. When the robot passes through the pipe deformation section, the diameter reduction section, or when the diameter-changing mechanism contracts due to its own weight, the support force will increase linearly with the increase of spring compression. For heavy-duty equipment, the sudden increase in support force can easily cause mechanical lock-up between the robot and the pipe wall; while in the diameter expansion section, the sudden drop in support force can cause the drive wheel to slip and the odometer wheel to lose signal. Current technology lacks a physical adjustment mechanism that can neutralize the linear change in spring force.

[0005] Third, the challenge of navigating large, heavy-duty robots through complex pipe terrains. Traditional large-diameter robots, due to their long bodies and mostly rigid connections, are prone to interference with pipe walls when navigating complex terrains such as L-shaped bends and deformed sections.

[0006] In summary, existing pipe robot diameter changing and support solutions face insurmountable technical bottlenecks in large-diameter, heavy-load, and long-distance operation scenarios, including low centering accuracy, poor operational stability, and high risk of jamming. Therefore, it is necessary to develop an adaptive centering internal detection device that can forcibly overcome heavy-load eccentricity using mechanical geometric constraints and output a constant radial preload. Summary of the Invention

[0007] The purpose of this invention is to provide a statically indeterminate centering and constant preload internal inspection robot for large-diameter heavy-duty pipelines, so as to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following solution: The present invention provides a large-diameter, heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot, comprising: A traction system includes a central cabin, a main shaft, deformation brackets, a drive wheel, and a drive module. Several sets of deformation brackets are provided. The main shaft passes through the central cabin. Several sets of deformation brackets are circumferentially and evenly spaced on the outer walls at both ends of the main shaft. A central slider is slidably connected to the main shaft. The deformation brackets are hinged to the central slider. A preload spring is provided between the central slider and the central cabin. The drive wheel is rotatably connected to the end of the deformation bracket. The drive module is fixed to the deformation bracket, and the drive module and the drive wheel are in a transmission cooperation. A detection system is installed on the drive wheel; A power supply system, which is hinged to the end of the spindle; A control system is mounted on the spindle and is connected to the detection system.

[0009] According to the present invention, the deformation support of the large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot includes a main arm and a secondary arm. One end of the main arm is hinged to a fixed base on the main shaft, and the other end of the main arm is rotatably connected to the power wheel. One end of the secondary arm is hinged to the outer periphery of the central slider, and the other end of the secondary arm is hinged to the middle of the main arm. All the secondary arms are hinged to the same central slider.

[0010] According to the present invention, the large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot includes a drive module comprising a motor base support, a drive motor, and a pair of bevel gears. The motor base support is fixed to the end of the main arm, the drive motor is fixed to the motor base support, the output shaft of the drive motor is arranged perpendicularly to the rotation axis of the power wheel at 90°, and the pair of bevel gears are respectively fixed to the output shaft of the drive motor and the axle of the power wheel, and the pair of bevel gears mesh at 90°.

[0011] According to the present invention, the large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot includes a rotary encoder and a non-destructive testing sensor array. The rotary encoder is coaxially mounted on the axle of the power wheel at the end of the deformation support of the inspection system. The non-destructive testing sensor array is circumferentially arranged on the outer wall of the central cabin. The rotary encoder and the non-destructive testing sensor array are electrically connected to the control system.

[0012] According to the present invention, the power supply system of the large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot includes a battery pack and an axial-flow fluid power generation module. The battery pack is installed inside the central compartment of the power supply system. The axial-flow fluid power generation module is coaxially disposed at the tail of the central compartment of the power supply system. The axial-flow fluid power generation module includes a generator compartment and generator blades. The generator blades are coaxially connected to the generator rotor inside the generator compartment. The battery pack and the axial-flow fluid power generation module are electrically connected to the control system.

[0013] According to the large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot provided by the present invention, the generator fan blades are connected to the main shaft through a cross-type universal joint coupling.

[0014] According to the large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot provided by the present invention, the central slider is slidably mounted on the main shaft through two linear bearings, the preload spring is coaxially mounted on the main shaft, one end of the preload spring abuts against the end face of the central slider facing the central chamber, and the other end of the preload spring abuts against the end face of the central chamber.

[0015] The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot provided by the present invention has a traction system with an adaptable diameter range of 910mm to 1030mm.

[0016] The present invention discloses the following technical effects: This invention adopts an integrated design of statically indeterminate centering and constant pre-tension. Multiple sets of circumferentially spaced deformation supports form a statically indeterminate support system. Combined with the adaptive adjustment function of the pre-tension spring, it can accurately adapt to the inner diameter fluctuations and irregular deformations of the pipe wall in large-diameter heavy-duty pipelines, always keeping the robot center aligned with the pipeline axis, while maintaining a constant pressure of the power wheel on the pipe wall. This completely solves the problems of slippage, jamming, and inaccurate centering of traditional inspection robots, and greatly improves operational stability.

[0017] This invention integrates the detection system directly onto the drive wheels, maintaining a close and constant detection distance between the detection probe and the inner wall of the pipe. This effectively eliminates the impact of detection distance fluctuations on detection accuracy and significantly improves the detection rate of minute defects. Multiple drive wheels are equipped with the detection system, achieving 360-degree full coverage detection of the pipe's inner wall without blind spots. This avoids the detection blind spots present in traditional detection devices, ensuring that pipe defects can be comprehensively and accurately detected.

[0018] This invention adopts a modular structure design, with the traction system, detection system, power supply system, and control system being independent and easy to disassemble and maintain, thus reducing the cost of equipment use and maintenance. The through-type main shaft structure, combined with the symmetrically arranged deformation supports at both ends, significantly improves the robot's overall load-bearing capacity and structural strength, enabling it to meet the requirements of long-distance, high-intensity inspection operations on large-diameter, heavy-duty pipelines and extending the service life of the equipment. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a front view of the overall structure of the large-diameter heavy-duty pipeline ultra-static indeterminate centering and constant preload internal inspection robot of the present invention; Figure 2 This is a schematic diagram of the traction system of the present invention; Figure 3 This is an isometric view of the overall structure of the large-diameter heavy-duty pipeline ultrastatic indeterminate centering and constant preload internal inspection robot of the present invention; Figure 4 This is a schematic diagram of the series structure of the multi-traction system of the present invention.

[0021] The components include: 1. Motor base support; 2. Main boom; 3. Motor; 4. Bevel gear; 5. Center slider; 6. Auxiliary boom; 7. Generator nacelle; 8. Power wheel; 9. Main shaft; 10. Generator fan blade; 11. Preload spring; 12. Center nacelle; 13. Cross-shaft universal joint coupling; and 14. Encoder. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figures 1-4 This invention provides a large-diameter, heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot, comprising: The traction system includes a central cabin 12, a main shaft 9, a deformation bracket, a power wheel 8, and a drive module. Several sets of deformation brackets are provided. The main shaft 9 passes through the central cabin 12. Several sets of deformation brackets are installed circumferentially at equal intervals on the outer walls at both ends of the main shaft 9. A central slider 5 is slidably connected to the main shaft 9. The deformation brackets are hinged to the central slider 5. A preload spring 11 is provided between the central slider 5 and the central cabin 12. The power wheel 8 is rotatably connected to the end of the deformation bracket. The drive module is fixed on the deformation bracket. The drive module and the power wheel 8 are connected by transmission. The detection system is installed on the drive wheel 8; The power supply system is hinged at the end of the main spindle 9; The control system is mounted on the spindle 9 and is connected to the detection system.

[0025] Once the robot is inserted into the large-diameter, heavy-duty pipe to be inspected, the preload spring 11 releases its elastic potential energy, pushing the central slider 5 to slide axially along the main shaft 9. The central slider 5, through a hinged structure, drives multiple sets of deformation supports arranged at equal intervals around the two ends of the main shaft 9 to open outwards synchronously, ensuring that the power wheels 8 at the ends of the deformation supports fit tightly against the inner wall of the pipe, achieving initial centering and preload for the robot within the pipe. After the drive module is activated, it drives the power wheels 8 to rotate via a transmission mechanism, propelling the robot to move at a constant speed along the pipe's axial direction. Simultaneously, the detection system mounted on the power wheels 8 collects real-time data on corrosion, cracks, deformation, and weld defects on the inner wall of the pipe, transmitting the data to the control system for processing and storage. When the pipe's inner diameter fluctuates, the pipe wall becomes uneven, or obstacles are encountered, the preload spring 11 automatically compresses or extends, adjusting the axial position of the central slider 5, thereby changing the opening angle of the deformation supports. This maintains a constant preload force on the inner wall of the pipe from the power wheels 8, effectively preventing slippage and jamming. Thanks to the use of multiple sets of circumferentially spaced, statically indeterminate deformation support structures, even if individual drive wheels 8 come into contact with local defects or obstacles in the pipeline, the remaining deformation supports can still work together to keep the central chamber 12 and the main shaft 9 always positioned on the pipeline's central axis, ensuring a constant detection distance and improving the accuracy of the detection data. The power supply system provides continuous and stable power support to the drive module, detection system, and control system. The control system, based on the detection data and preset programs, adjusts the operating status of the drive module in real time, enabling the robot's autonomous navigation, speed adjustment, and emergency fault handling, thus completing the internal inspection of the entire pipeline.

[0026] Further optimization of the scheme: the deformation support includes a main arm 2 and a secondary arm 6. One end of the main arm 2 is hinged to a fixed base on the main shaft 9, and the other end of the main arm 2 is rotatably connected to the power wheel 8. One end of the secondary arm 6 is hinged to the outer periphery of the central slider 5, and the other end of the secondary arm 6 is hinged to the middle of the main arm 2. One end of all the secondary arms 6 is hinged to the same central slider 5.

[0027] Eight circumferentially equidistant main and auxiliary arm assemblies 6 form a rigid kinematic constraint through a single central slider 5, forcing the entire variable-diameter mechanism to a single degree of freedom: sliding only along the main shaft 9. When the 300kg heavy-duty fuselage experiences a tendency to sink due to gravity, the radial contraction displacement of the bottom drive wheel 8 caused by the compression of the pipe wall is converted into an axial backward movement of the central slider 5 through the bottom auxiliary arm 6. Since all auxiliary arms 6 share the same central slider 5, this axial displacement is synchronously and indiscriminately transmitted to all the top and side main arms 2, forcing them to produce absolutely equal radial contraction. Ultimately, the gravity load that would originally cause fuselage eccentricity is completely converted into an axial balancing internal force between the central slider 5 and the preload spring 11, achieving a uniform distribution of preload force across the entire circumferential wheel system. This ensures that the geometric center of the fuselage and the center of the pipe are always tightly aligned, and the centering accuracy depends only on the machining accuracy of the connecting rods, completely solving the fuselage sinking eccentricity problem caused by uneven spring force in traditional structures.

[0028] The scheme is further optimized. The drive module includes a motor base support 1, a drive motor 3 and a pair of bevel gears 4. The motor base support 1 is fixed to the end of the main arm 2. The drive motor 3 is fixed on the motor base support 1. The output shaft of the drive motor 3 is arranged perpendicularly to the rotation axis of the power wheel 8 at 90°. The pair of bevel gears 4 are fixed on the output shaft of the drive motor 3 and the axle of the power wheel 8 respectively. The pair of bevel gears 4 mesh at 90° for transmission.

[0029] The drive motor 3 is arranged axially along the main arm 2, and the power is transmitted in a 90° reversal direction through a pair of meshing bevel gears 4. This layout can compress the radial dimension of the gear train, providing more radial movement space for the variable diameter mechanism; the motor base support 1 also serves as a load-bearing structure, which can enhance the rigidity of the end of the main arm 2 and withstand the torque load during traction. The bevel gear 4 transmission can transmit the power of the drive motor 3 to the drive wheel 8, so that the drive wheel 8 can drive the robot to move by friction with the tube wall.

[0030] The scheme is further optimized. The detection system includes a rotary encoder 14 and a non-destructive testing sensor array. The rotary encoder 14 is coaxially mounted on the axle of the power wheel 8 at the end of the deformation bracket of the detection system. The non-destructive testing sensor array is arranged circumferentially on the outer wall of the central cabin 12. The rotary encoder 14 and the non-destructive testing sensor array are electrically connected to the control system.

[0031] A rotary encoder 14 is mounted on the driven wheel axle of the detection section. Under constant preload, the driven wheel is in contact with the pipe wall. The encoder 14 acquires the robot's travel distance information by collecting the rotation data of the wheel axle. The non-destructive testing sensor array is arranged circumferentially along the outer wall of the central compartment 12, covering the entire circumferential range of the pipe's inner wall. With the robot body and the pipe coaxial, the distance between each sensor probe and the pipe wall remains consistent, allowing for the acquisition of stable detection data.

[0032] Further optimization of the scheme: the power supply system includes a battery pack and an axial-flow fluid power generation module. The battery pack is installed inside the central compartment 12 of the power supply system. The axial-flow fluid power generation module is coaxially arranged at the tail of the central compartment 12 of the power supply system. The axial-flow fluid power generation module includes a generator compartment 7 and a generator fan blade 10. The generator fan blade 10 is coaxially connected to the rotor of the generator 3 inside the generator compartment 7. The battery pack and the axial-flow fluid power generation module are electrically connected to the control system respectively.

[0033] The battery pack provides basic power to the entire unit; the axial-flow fluid generator module uses the kinetic energy of the medium flowing in the pipe to drive the generator fan blades 10 to rotate, which in turn drives the generator rotor 3 to generate electricity, which can replenish the battery pack. The control system manages the charging and discharging process of the battery pack and the operating status of the generator module to ensure the stability of the power supply to the entire unit.

[0034] In a further optimized design, the generator fan blade 10 is connected to the main shaft 9 via a cross-type universal joint coupling 13.

[0035] When the robot passes through bends or deformed pipe sections, an angular deviation will occur between the generator section and the main shaft 9. The universal joint coupling can compensate for this angular deviation and transmit rotational torque to keep the generator blades 10 rotating. In addition, the universal joint coupling can also absorb the impact load generated by pipe vibration and reduce the stress deformation of shaft components.

[0036] In a further optimized design, the central slider 5 is slidably mounted on the main shaft 9 via two linear bearings, and the preload spring 11 is coaxially mounted on the main shaft 9. One end of the preload spring 11 abuts against the end face of the central slider 5 facing the central chamber 12, and the other end of the preload spring 11 abuts against the end face of the central chamber 12.

[0037] Two linear bearings provide axial guidance for the central slider 5, limiting its radial runout and allowing it to slide smoothly along the axis of the main shaft 9. A preload spring 11 is coaxially mounted, and its axial force acts directly on the central slider 5, providing initial preload for the diameter-changing mechanism. When the pipe's inner diameter changes, the compression of the preload spring 11 changes accordingly, adjusting the contact pressure between the power wheel 8 and the pipe wall via the connecting rod assembly.

[0038] The design was further optimized so that the traction system can be adapted to diameter ranges from 910mm to 1030mm.

[0039] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A statically indeterminate centering and constant preload internal inspection robot for large-diameter heavy-duty pipelines, characterized in that, include: The traction system includes a central cabin (12), a main shaft (9), a deformation bracket, a power wheel (8), and a drive module. The deformation bracket is provided in several groups. The main shaft (9) passes through the central cabin (12). Several groups of deformation brackets are installed circumferentially at equal intervals on the outer walls at both ends of the main shaft (9). A central slider (5) is slidably connected to the main shaft (9). The deformation bracket is hinged to the central slider (5). A preload spring (11) is provided between the central slider (5) and the central cabin (12). The power wheel (8) is rotatably connected to the end of the deformation bracket. The drive module is fixed on the deformation bracket. The drive module and the power wheel (8) are in transmission cooperation. A detection system is installed on the drive wheel (8); A power supply system, which is hinged to the end of the main shaft (9); A control system is installed on the main shaft (9) and is connected to the detection system.

2. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 1, characterized in that, The deformation support includes a main arm (2) and a secondary arm (6). One end of the main arm (2) is hinged to a fixed base on the main shaft (9), and the other end of the main arm (2) is rotatably connected to the power wheel (8). One end of the secondary arm (6) is hinged to the outer periphery of the central slider (5), and the other end of the secondary arm (6) is hinged to the middle of the main arm (2). One end of all the secondary arms (6) is hinged to the same central slider (5).

3. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 2, characterized in that, The drive module includes a motor base support (1), a drive motor (3) and a pair of bevel gears (4). The motor base support (1) is fixed to the end of the main arm (2). The drive motor (3) is fixed on the motor base support (1). The output shaft of the drive motor (3) is arranged perpendicularly to the rotation axis of the power wheel (8) at 90°. The pair of bevel gears (4) are respectively fixed on the output shaft of the drive motor (3) and the axle of the power wheel (8). The pair of bevel gears (4) mesh at 90°.

4. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 1, characterized in that, The detection system includes a rotary encoder (14) and a non-destructive testing sensor array. The rotary encoder (14) is coaxially mounted on the axle of the power wheel (8) at the end of the deformation support of the detection system. The non-destructive testing sensor array is circumferentially arranged on the outer wall of the central cabin (12). The rotary encoder (14) and the non-destructive testing sensor array are electrically connected to the control system.

5. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 1, characterized in that, The power supply system includes a battery pack and an axial flow fluid power generation module. The battery pack is installed inside the central compartment (12) of the power supply system. The axial flow fluid power generation module is coaxially arranged at the tail of the central compartment (12) of the power supply system. The axial flow fluid power generation module includes a generator compartment (7) and a generator fan blade (10). The generator fan blade (10) is coaxially connected to the rotor of the generator (3) inside the generator compartment (7). The battery pack and the axial flow fluid power generation module are electrically connected to the control system.

6. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 5, characterized in that, The generator fan blade (10) is connected to the main shaft (9) via a cross-type universal joint coupling (13).

7. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 1, characterized in that, The central slider (5) is slidably mounted on the main shaft (9) through two linear bearings. The preload spring (11) is coaxially mounted on the main shaft (9). One end of the preload spring (11) abuts against the end face of the central slider (5) facing the central cabin (12), and the other end of the preload spring (11) abuts against the end face of the central cabin (12).

8. The large-diameter heavy-duty pipeline statically indeterminate centering and constant preload internal inspection robot according to claim 1, characterized in that, The traction system is compatible with diameter variations ranging from 910mm to 1030mm.

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