A multi-diameter misaligned pipe-holding wall-climbing robot for ultrasonic inspection of outer pipes

Abstract

The present invention discloses a multi-diameter misaligned pipe-holding wall-climbing robot for external pipe ultrasonic detection, which includes a misaligned pipe-holding main body, a front driving wheel unit, a driven wheel unit, a rear driving wheel unit, a pipe-holding driving unit, and an ultrasonic detection unit. The present invention tightens the wire rope through a wire-winding motor to achieve adaptive misaligned clamping and adsorption of the pipe, and then performs stable wall climbing and ultrasonic detection. Multiple robots can be spliced end to end with misalignment to move from the current pipe to the adjacent pipe and clamp it. The robot of the present invention is small, light, reasonable in structure, simple in control, stable in transmission, high in energy efficiency, and high in detection performance. It has an obstacle-crossing ability and a multi-probe system with diverse layouts. The parameters of the misaligned pipe-holding main body can be designed according to the range of the outer diameter of the pipe to be detected. Different diameter pipes, especially small-diameter pipes, can be adapted to automated detection by selecting the number of sub-segments of the misaligned pipe-holding main body, which can ensure the safe operation of the pipe while guaranteeing the safety of employees.

Description

Technical Field

[0001] The present invention relates to the field of pipeline robots, and more specifically, to a multi-diameter misaligned pipe-holding wall-climbing robot for external pipeline ultrasonic detection. Background Art

[0002] Pipeline transportation is one of the important means in the five major material transportation methods and is widely used in important fields such as national economy, national defense construction, and municipal livelihood. However, pipelines work in harsh environments and are prone to damage. Local damage can also lead to global paralysis, and the leakage of resources such as oil and gas caused by pipeline rupture will cause huge economic losses and ecological pollution. Therefore, the pipeline safety issue is particularly prominent. At the same time, it has become difficult to effectively monitor the pipeline safety status by manual means alone, and the manual inspection of pipelines has low efficiency, high cost, and great potential safety hazards.

[0003] In addition, the existing wall-climbing robots for external pipeline detection are large in size, heavy in weight, high in energy consumption, complex in design, difficult to control, poor in stability, poor in reliability, poor in obstacle-crossing ability, and low in detection efficiency, and it is difficult to adapt to the detection of pipelines with different diameters. Some wall-climbing robots for external pipeline detection use magnetic adsorption, but this technology has many problems. For example, pipelines are usually rusty, corroded, and covered with attachments, which will reduce the magnetic adsorption property of the pipeline, thus increasing the difficulty of achieving stable adsorption by magnetic force. And magnetic adsorption is not applicable to pipelines with weak magnetism or non-magnetic materials due to coatings such as anti-corrosion films. Some wall-climbing robots for external pipeline detection perform pipe climbing detection through a pipe-holding mechanism or a circular track laid outside the pipeline, but it is difficult to detect pipelines with different diameters, and the cost is high and the efficiency is low. At the same time, some wall-climbing robots for external pipeline detection are not applicable to pipelines with smaller diameters due to their too large size, too large detection equipment carried, insufficient adsorption force, or limited mobility. Some wall-climbing robots for external pipeline detection use visual inspection, but visual inspection is difficult to detect minute defects, and can only provide information on the pipeline surface, and cannot detect internal defects. It has high cost, low efficiency, low accuracy, limited data, and is also easily affected by the environment (for example, pipelines are sometimes covered with attachments, hiding the corroded or damaged parts of the pipeline, resulting in the failure of visual inspection), and cannot adapt to dim environments.

[0004] Therefore, developing a robot with a reasonable structure, small and light, convenient in design, simple to control, stable in movement, low in energy consumption, with high-performance ultrasonic detection function and good obstacle-crossing ability, and capable of self-adaptive clamping and adsorption on pipelines with different diameters, especially pipelines with smaller diameters, can solve the above problems, realize the automation of external pipeline detection, and ensure the safety of employees while improving efficiency. Summary of the Invention

[0005] In order to achieve the miniaturization, light weight, simplicity, economy, high efficiency, stability, reliability, multi-diameter applicability, high-performance ultrasonic detection function and obstacle-crossing function of the external pipeline inspection robot, the present invention provides a multi-diameter misaligned pipe-holding wall-climbing robot for external pipeline ultrasonic detection.

[0006] The object of the present invention is achieved by the following technical solutions: A multi-diameter misaligned pipe-holding wall-climbing robot for external pipeline ultrasonic detection, comprising a misaligned pipe-holding main body, a front driving wheel unit, a driven wheel unit, a rear driving wheel unit, a pipe-holding driving unit and an ultrasonic detection unit;

[0007] The misaligned pipe-holding main body is composed of several sub-segments connected in sequence with misalignment. Each sub-segment includes a first rigid body, a second rigid body, a first rigid link and a second rigid link; the first rigid body and the second rigid body are arranged in a misaligned mirror image and hinged to form an inverted V-shaped structure of the sub-segment; the first rigid link and the second rigid link misalign and connect the inverted V-shaped structures of the front and rear sub-segments, and the two inverted V-shaped structures are misaligned and hinged by adjacent sub-bodies to form an inverted W-shaped structure;

[0008] The front driving wheel unit has a first hub motor, which is misaligned and hinged to the first rigid body at the front end of the misaligned pipe-holding main body; the rear driving wheel unit has a second hub motor, which is misaligned and hinged to the second rigid body at the rear end of the misaligned pipe-holding main body; the driven wheel unit is hinged to the bottom of the second rigid body;

[0009] The pipe-holding driving unit includes a wire-winding motor, a wire-winding disc and a wire rope; the wire-winding motor is fixed on the rear driving wheel unit, the wire-winding disc is fixed on the rotating shaft of the wire-winding motor, one end of the wire rope is fixed on the wire-winding disc, and the other end passes through the rear driving wheel unit, each sub-segment of the misaligned pipe-holding main body and the bottom of the front driving wheel unit in sequence, and then passes back to the wire-winding disc in sequence and is fixed;

[0010] The ultrasonic detection unit is fixed on the front driving wheel unit, and realizes the ultrasonic detection of the external pipeline through an ultrasonic probe;

[0011] By driving the wire-winding motor to rotate the wire-winding disc to tighten the wire rope, the robot is misaligned and bent towards the side of the wire rope, and tightly adheres to the outer surface of the pipeline; by controlling the two hub motors, the robot performs circumferential pipe-climbing movement.

[0012] Further, the first rigid sub-body has a frame structure, with concave structures at the top and bottom, equal wall thicknesses on the left and right sides, and horizontal through-holes are provided at the upper and lower ends on both the left and right sides. A vertical support column is provided in the middle, dividing the first rigid sub-body into left and right hollow areas. Horizontal through-holes are provided in the middle of both the left and right sides and the middle of the support column of the first rigid sub-body; the second rigid sub-body is hinged to the first rigid sub-body through the upper horizontal through-holes on both the left and right sides. The inner wall on the right side of the first rigid sub-body contacts the outer wall on the right side of the second rigid sub-body, and the outer wall on the left side of the first rigid sub-body contacts the inner wall on the left side of the second rigid sub-body, with a horizontal offset of the distance of one wall thickness between the two.

[0013] Further, through-holes are provided at both ends of the first rigid link, and it is hinged to the middle horizontal through-holes of the first rigid sub-bodies of the front and rear sub-segments, located in the left hollow area of the first rigid sub-body and the second rigid sub-body; through-holes are provided at both ends of the second rigid link, and it is hinged to the middle horizontal through-holes of the second rigid sub-bodies of the front and rear sub-segments, located in the right hollow area of the first rigid sub-body and the second rigid sub-body.

[0014] Further, the front drive wheel unit includes a front wheel connecting member, and the front wheel connecting member has a U-shaped structure lying flat forward. Horizontal through-holes are provided at the front ends on both the left and right sides for a first threaded fixing shaft for fixedly installing a first hub motor. A horizontal through-hole is provided at the lower end of the part connecting the rear ends on both the left and right sides in the U-shaped structure, and it is hinged to the lower horizontal through-holes on both the left and right sides of the first rigid sub-body at the very front end of the misaligned pipe-holding main body; vertical support columns are formed by hollowing out from both the left and right sides to the middle of the part connecting both the left and right sides in the U-shaped structure. A horizontal through-hole is provided in the middle of the support column. By adding a second rigid link, through-holes at both ends thereof are respectively hinged to the horizontal through-hole of the support column of the front wheel connecting member and the middle horizontal through-hole of the second rigid sub-body at the very front end of the misaligned pipe-holding main body.

[0015] Further, the rear drive wheel unit includes a rear wheel connection bin, and the rear wheel connection bin is composed of an L-shaped structure and a U-shaped structure lying flat backward; horizontal through-holes are provided at the rear ends on both the left and right sides of the U-shaped structure for a second threaded fixing shaft for fixedly installing a second hub motor. A horizontal through-hole is provided at the lower end of the part connecting the front ends on both the left and right sides in the U-shaped structure, and it is hinged to the lower horizontal through-holes on both the left and right sides of the second rigid sub-body at the very rear end of the misaligned pipe-holding main body; the L-shaped structure is a hollow bin body for placing a circuit board arranged above and behind the U-shaped structure; vertical support columns are formed by hollowing out from both the left and right sides to the middle of the part connecting both the left and right sides in the U-shaped structure. A horizontal through-hole is provided in the middle of the support column. Through-holes at both ends of the first rigid link at the very rear end of the misaligned pipe-holding main body are respectively hinged to the horizontal through-hole of the support column of the rear wheel connection bin and the middle horizontal through-hole of the first rigid sub-body at the very rear end of the misaligned pipe-holding main body, and the second rigid link is removed from the sub-segment at the very rear end of the misaligned pipe-holding main body.

[0016] Further, the front and rear sub-segments of the misaligned pipe-holding body are misaligned and connected without structural interference, and it is necessary to satisfy t 2 ≤2t 1 ,t 3 ≥2t 2 ,and 2t 1 <t 3 ≤(T - 2t 1 ) / 2, where t 1 is the wall thickness on both left and right sides of the rigid sub-body, t 2 is the thickness of the rigid connecting rod, t 3 is the width of each hollow area of the rigid sub-body, and T is the width of the rigid sub-body; there is no structural interference between the driven wheel units of the front and rear sub-segments of the misaligned pipe-holding body when the robot misaligns to hold the pipe, and it is necessary to satisfy t 4 <2t 1 ,where t 4 is the thickness of the driven wheel.

[0017] Further, the minimum number of sub-segments of the misaligned pipe-holding body is determined according to the pipe diameter. The misaligned pipe-holding body holds at least one circle of the outer pipe. When the misaligned pipe-holding body holds one circle of the outer pipe, the pipe diameter D and the minimum number of sub-segments N min of the misaligned pipe-holding body satisfy , where H is the distance from the center of the horizontal through-hole in the middle of the rigid sub-body to the ground when the robot is placed flat on the ground, C is the center distance of the through-holes at both ends of the rigid connecting rod, is an intermediate parameter. When the pipe diameter D is determined, first calculate , and then round up to obtain the minimum number of sub-segments N min ; when it is required that the misaligned pipe-holding body holds n circles of the outer pipe, multiply by n and round up to obtain the number of sub-segments N of the misaligned pipe-holding body.

[0018] Further, the parameter design of the misaligned pipe-holding body is specifically as follows:

[0019] The robot has a minimum applicable pipe diameter D min , and the applicable pipe diameter D of the robot ≥ D min ;

[0020] When the robot misaligns to hold the pipe, the pipe diameter D, the distance h from the center of the horizontal through-hole at the lower end of the rigid sub-body to the ground when the robot is placed flat on the ground, the center distance L between the horizontal through-holes at the upper and lower ends of the rigid sub-body, and the angle The included angle between the straight line formed by the upper transverse through-hole and the lower transverse through-hole of the second rigid sub-body and the straight line formed by the upper transverse through-hole and the lower transverse through-hole of the first rigid sub-body of the next sub-segment Satisfies Equation (1):

[0021] (1)

[0022] L, , And the center distance C of the through-holes at both ends of the rigid connecting rod satisfy Equation (2):

[0023] (2)

[0024] The bending degree of the robot when misaligned and holding the pipe depends on the outer diameter of the pipe. The minimum value of And The maximum value of Are determined by the structure of the robot. When the robot reaches the limit bending degree, , , D = D min ;

[0025] First, design the outer shape of the rigid sub-body, and determine And As well as h when the robot reaches the limit bending degree. Then, determine the range of the pipe diameter D applicable to the robot according to the different outer diameters of various pipes to be detected. Substitute , D = D min And h into Equation (1) to obtain L; alternatively, first design the outer shape of the rigid sub-body and L, and then calculate D = D min From Equation (1), and verify whether D min Is less than or equal to the minimum pipe diameter in the pipes to be detected. If not satisfied, modify L until satisfied; then substitute , And L into Equation (2) to obtain C; The calculation formula for H is , where when the robot is placed flat on the ground , The value of is determined when the outer shape of the rigid sub-body is designed;

[0026] According to D = D min , H and C, calculate the minimum number of sub-segments Required for the robot when misaligned and holding the minimum diameter pipe. , t 1 And T satisfy ; Then, combined with t 2 ≤2t 1 , t 3 ≥2t 2 And 2t1 <t 3 ≤(T - 2t 1 ) / 2 to determine the wall thickness t on both the left and right sides of the rigid sub - body 1 , the thickness t of the rigid connecting rod 2 , the width t of each hollow area of the rigid sub - body 3 and the width T of the rigid sub - body.

[0027] Furthermore, the coiling motor adopts a servo motor, and the change of the torque of the servo motor is reflected by real - time monitoring of the change of the current of the servo motor:

[0028] When the current of the servo motor increases, it indicates that the robot encounters a convex obstacle. Control the coiling motor to release the wire rope to restore the torque. When the convex obstacle becomes smaller or the robot crosses the convex obstacle, the current of the servo motor decreases, and control the coiling motor to tighten the wire rope to maintain the torque;

[0029] When the current of the servo motor decreases, it indicates that the robot encounters a concave obstacle. Control the coiling motor to tighten the wire rope to restore the torque. When the concave obstacle becomes smaller or the robot crosses the concave obstacle, the current of the servo motor increases, and control the coiling motor to release the wire rope to maintain the torque.

[0030] Furthermore, by splicing three or more of the said robots end - to - end with misalignment, the spliced robot can automatically move from the current pipeline to the adjacent pipe and hold it tightly; by installing springs between two adjacent holes through which the wire rope passes, the automatic reset and maintenance after the wire rope is lengthened when the robot bends are realized; during the splicing process, the front - most robot removes the rear drive wheel unit and fixes the coiling motor on the last sub - segment; the middle - part robots remove the front drive wheel unit and the rear drive wheel unit and fix the coiling motor on the last sub - segment; the rearmost robot removes the front drive wheel unit, and the wire rope of the rear robot passes through the bottom of the second rigid sub - body of the last sub - segment of the front robot, and no rigid connecting rod is assembled between the two sub - segments at the splicing point.

[0031] The beneficial effects of the present invention are:

[0032] 1. The robot of the present invention can rotate the coiling disk to tighten the wire rope by driving the coiling motor, so that the robot bends with misalignment, thereby realizing the self - adaptive stable holding and adsorption of the robot to the pipeline, and is not affected by the pipeline material and surface conditions. At the same time, the more turns the robot holds the pipe, the more stable its adsorption movement on the outer surface of the pipeline.

[0033] 2. The robot of the present invention has several hollow areas, adopts lightweight materials, and is composed of several offset pipe-holding body sub-segments and driven wheel units. The parameters of the offset pipe-holding body can be designed according to the outer diameter range of the pipe to be detected, and the number of the offset pipe-holding body sub-segments can be selected according to the pipe diameter. Due to the offset design, structural interference can be avoided when the robot holds the pipe in an offset manner. After removing the wire rope, the sub-segments can be easily added or removed, and the assembled robot can also be disassembled into multiple parts according to different numbers of sub-segments for storage, transportation and subsequent assembly and use. The driven wheel units can also be easily added or removed to reasonably optimize their layout. Therefore, the robot is compact and light, convenient in design, and reasonable in structure. It can adapt to pipes of different diameters, especially pipes with smaller diameters.

[0034] 3. The driving device of the robot of the present invention has only two wheel hub motors and one winding motor, has the ability to overcome obstacles, is simple to control, has stable movement and low energy consumption; the robot of the present invention is assembled with a rigid sub-body, a rigid connecting rod, a rigid front wheel connecting piece, a rigid rear wheel connecting bin and pins, and uses a driven wheel unit to assist in climbing the pipe, thereby ensuring the stability of the robot's transmission, adsorption and movement.

[0035] 4. The robot of the present invention adopts ultrasonic detection, which can detect tiny defects inside the pipeline. It has low cost, high efficiency, high precision, rich data, and is not easily affected by the environment. At the same time, multiple ultrasonic probes can be used and arranged in a diversified manner. The multi-probe system of the robot can be composed of a variety of different ultrasonic probes, and a variety of ultrasonic detection technologies can also be integrated to improve the detection range and performance and meet a variety of detection requirements, thereby realizing the automation of external pipeline detection, improving economic benefits, ensuring the safe operation of the pipeline and protecting the safety of employees.

[0036] 5. In order to further improve the automation and working efficiency of the robot, the present invention also designs multiple robots to hold adjacent pipes, and splices multiple robots head to tail in a staggered manner to realize that the spliced ​​robots automatically move from the current pipe to the adjacent pipe and hold it tightly. A spring is installed between the two adjacent holes in front and behind where the wire rope passes, so as to realize the automatic reset and retention of the wire rope after it is lengthened when the robot is bent. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 This is a schematic diagram of a multi-diameter dislocated pipe-holding wall-climbing robot for external pipeline ultrasonic testing;

[0039] Figure 2 Schematic diagram of the misaligned pipe-gripping main body;

[0040] Figure 3 Schematic diagram of the sub-segment of the misaligned pipe-gripping main body, where (a) is the structure diagram of a single sub-segment, (b) is the structure diagram of the rigid sub-body, and (c) is the structure diagram of the rigid connecting rod;

[0041] Figure 4 Schematic diagrams of two different perspectives of the front drive wheel unit;

[0042] Figure 5 Schematic diagrams of two different perspectives of the driven wheel unit;

[0043] Figure 6 Schematic diagram of the rear drive wheel unit;

[0044] Figure 7 Schematic diagram of the pipe-gripping drive unit;

[0045] Figure 8 Schematic diagram of the ultrasonic detection unit;

[0046] Figure 9 Schematic diagram of the misalignment design of the misaligned pipe-gripping main body;

[0047] Figure 10 Schematic diagram of the parameters of a certain sub-segment when the front and rear sub-segments of the misaligned pipe-gripping main body are tightly misaligned and connected;

[0048] Figure 11 Schematic diagram of the parameters when the misaligned pipe-gripping main body holds the outer pipe for one circle;

[0049] Figure 12 Schematic diagram of the parameters when the robot is placed flat on the ground without bending;

[0050] Figure 13 Schematic diagram of the robot after three robots are misaligned and spliced end to end;

[0051] Figure 14 Schematic diagram when the side of the first robot with the driven wheel unit approaches the adjacent pipe;

[0052] Figure 15 Schematic diagram of the first robot holding the adjacent pipe;

[0053] Figure 16 Schematic diagram of the third robot automatically resetting to the straight state and maintaining under the action of the spring;

[0054] Figure 17 Schematic diagram after the second robot and the third robot successively hold the adjacent pipes;

[0055] In the figure: 1. First rigid sub-body, 2. Second rigid sub-body, 3. First rigid connecting rod, 4. Second rigid connecting rod, 5. Front wheel connecting piece, 6. First threaded fixing shaft, 7. First hub motor, 8. Connecting shaft, 9. Driven wheel, 10. Rear wheel connecting bin, 11. Bin cover, 12. Second threaded fixing shaft, 13. Second hub motor, 14. Wire winding motor, 15. Wire winding disc, 16. Wire rope, 17. Fixed bracket, 18. Rotating bracket, 19. Ultrasonic probe. Detailed implementation manners

[0056] For a better understanding of the technical solution of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0057] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0058] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0059] As Figure 1 shown, the present invention provides a multi-diameter misaligned pipe-holding wall-climbing robot for external pipeline ultrasonic detection, including a misaligned pipe-holding main body, a front driving wheel unit, a driven wheel unit, a rear driving wheel unit, a pipe-holding driving unit and an ultrasonic detection unit.

[0060] As Figure 2 shown, the misaligned pipe-holding main body is composed of N sub-segments. As Figure 3 shown in (a) of Figure 3As shown in Fig. (b), the first rigid sub-body 1 has a frame structure, with concave structures at the top and bottom. Horizontal through-holes running from left to right are provided at the upper and lower ends on both the left and right sides of the first rigid sub-body 1. A vertical support column is provided in the middle of the first rigid sub-body 1, dividing the first rigid sub-body 1 into two hollow areas on the left and right. Horizontal through-holes are also provided in the middle of both the left and right sides and the middle of the support column of the first rigid sub-body 1; the wall thicknesses on both the left and right sides of the first rigid sub-body 1 are equal. The second rigid sub-body 2 has the same structure as the first rigid sub-body 1 and is arranged in a misaligned mirror image with the first rigid sub-body 1. The two are hinged through the upper horizontal through-holes on both the left and right sides. The inner wall on the right side of the first rigid sub-body 1 contacts the outer wall on the right side of the second rigid sub-body 2, and the outer wall on the left side of the first rigid sub-body 1 contacts the inner wall on the left side of the second rigid sub-body 2. The two are horizontally offset by a distance equal to one wall thickness. Thus, an inverted V-shaped structure of the sub-segment is formed. Moreover, the second rigid sub-body 2 and the first rigid sub-body 1 of the next sub-segment are hinged through the lower horizontal through-holes on both the left and right sides. The inner wall on the right side of the second rigid sub-body 2 contacts the outer wall on the right side of the first rigid sub-body 1 of the next sub-segment, and the outer wall on the left side of the second rigid sub-body 2 contacts the inner wall on the left side of the first rigid sub-body 1 of the next sub-segment. The two are horizontally offset by a distance equal to one wall thickness. As Figure 3 As shown in Fig. (c), the first rigid connecting rod 3 has a rod structure, with through-holes at both ends, and is hinged to the middle horizontal through-holes of the first rigid sub-bodies 1 of the front and rear sub-segments. It is located in the left hollow area of the first rigid sub-body 1 and the second rigid sub-body 2; the second rigid connecting rod 4 has the same structure as the first rigid connecting rod 3. The through-holes at both ends of the second rigid connecting rod 4 are hinged to the middle horizontal through-holes of the second rigid sub-bodies 2 of the front and rear sub-segments. It is located in the right hollow area of the first rigid sub-body 1 and the second rigid sub-body 2; thus, the first rigid connecting rod 3 and the second rigid connecting rod 4 connect the inverted V-shaped structures of the front and rear sub-segments in a misaligned manner.

[0061] As Figure 4 shown, the front drive wheel unit includes a front wheel connecting member 5, a first threaded fixing shaft 6, and a first hub motor 7; the front wheel connecting member 5 has a U-shaped structure lying flat forward, with two threaded holes on the right side, horizontal through-holes at the front ends on both the left and right sides, and a horizontal through-hole at the lower end of the part connecting the rear ends on both the left and right sides in the U-shaped structure. It is hinged to the lower horizontal through-holes on both the left and right sides of the first rigid sub-body 1 at the very front end of the misaligned pipe-holding main body; the middle of the first threaded fixing shaft 6 is smooth, with external threads on both sides. The first threaded fixing shaft 6 is fixed to the horizontal through-holes at the front ends on both the left and right sides of the front wheel connecting member 5 by assembling nuts on the external threads; the first hub motor 7 is located between the left and right sides of the front wheel connecting member 5 and is fixed to the middle of the first threaded fixing shaft 6 by assembling nuts on the external threads of the first threaded fixing shaft 6.

[0062] As Figure 5As shown in the figure, the driven wheel unit includes a connecting shaft 8 and a driven wheel 9; the connecting shaft 8 is hinged to the bottom of the second rigid body 2 of the misaligned pipe-holding main body; the driven wheel 9 is fixed on the connecting shaft 8 by a flat key and is located at the concave structure of the second rigid body 2 of the misaligned pipe-holding main body.

[0063] As Figure 6 shown in the figure, the rear drive wheel unit includes a rear wheel connection bin 10, a bin cover 11, a second threaded fixing shaft 12 and a second hub motor 13; the rear wheel connection bin 10 is composed of an L-shaped structure and a U-shaped structure lying flat backward. In this embodiment, seven through holes are opened on the left side of the U-shaped structure, transverse through holes are opened at the rear ends of the left and right sides, and a transverse through hole is opened at the lower end of the part connecting the front ends of the left and right sides in the U-shaped structure, and is hinged to the transverse through holes at the lower ends of the left and right sides of the second rigid body 2 at the rearmost end of the misaligned pipe-holding main body. The L-shaped structure is a hollow bin body for placing a circuit board arranged above and behind the U-shaped structure; the bin cover 11 is in a cuboid structure and is fixed by screws behind the hollow bin body of the rear wheel connection bin 10; the middle part of the second threaded fixing shaft 12 is smooth and has external threads on both sides, and the second threaded fixing shaft 12 is fixed to the transverse through holes at the rear ends of the left and right sides of the U-shaped structure of the rear wheel connection bin 10 by assembling nuts on the external threads; the second hub motor 13 is located between the left and right sides of the U-shaped structure of the rear wheel connection bin 10, and the second hub motor 13 is fixed to the middle part of the second threaded fixing shaft 12 by assembling nuts on the external threads of the second threaded fixing shaft 12.

[0064] As Figure 7 shown in the figure, the pipe-holding drive unit includes a winding motor 14, a winding disc 15 and a wire rope 16; in this embodiment, the winding motor 14 is a micro high-torque high-precision motor, which is fixed to the outside of the through hole on the left side of the U-shaped structure of the rear wheel connection bin 10 by six screws, and its rotating shaft extends into the inside through the through hole; the middle part of the winding disc 15 is in a shaft shape and the two sides are in a disc structure, which is fixed to the rotating shaft of the winding motor 14 and is located between the left and right sides of the U-shaped structure of the rear wheel connection bin 10; one end of the wire rope 16 is fixed to the shaft of the winding disc 15, and the other end passes through the rear wheel connection bin 10, the misaligned pipe-holding main body and the bottom of the front wheel connector 5 in sequence, and then passes through the front wheel connector 5, the misaligned pipe-holding main body and the bottom of the rear wheel connection bin 10 in sequence, and returns to the shaft of the winding disc 15 and is fixed. Preferably, metal hollow rivets can be installed in the holes through which the wire rope 16 passes to reduce the wear of the wire rope during movement and improve the service life of the wire rope.

[0065] As Figure 8As shown in the figure, the ultrasonic detection unit includes a fixed bracket 17, a rotating bracket 18, and an ultrasonic probe 19. The fixed bracket 17 has a rectangular parallelepiped structure, with two horizontal through holes, and a protruding cylindrical structure on its surface. There are threaded holes on the outside of the cylindrical structure. The two horizontal through holes of the fixed bracket 17 can be connected to the two threaded holes on the right side of the front wheel connector 5 through screws, so as to fix the fixed bracket 17 to the outside of the right side of the front wheel connector 5. The rotating bracket 18 has a tubular structure, with a shaft-like structure outside the tubular structure. The symmetry axes of the two are perpendicular to each other, and there are threaded holes on the outside of the tubular structure. The shaft-like structure of the rotating bracket 18 is installed in the cylindrical structure of the fixed bracket 17, and the rotating bracket 18 can be fixed or rotated by screwing screws into the threaded holes in the cylindrical structure of the fixed bracket 17. The ultrasonic probe 19 is installed in the tubular structure of the rotating bracket 18, and the ultrasonic probe 19 can be fixed or moved by screwing screws into the threaded holes in the tubular structure of the rotating bracket 18.

[0066] Further, as Figure 1 , Figure 4 and Figure 6 shown, in the U-shaped structures of the front wheel connector 5 and the rear wheel connection bin 10, the left and right sides of the parts connecting the left and right sides are hollowed out to form vertical support columns in the middle. There are horizontal through holes in the middle of the support columns. By adding a second rigid link 4, the through holes at both ends are hinged to the horizontal through holes of the support columns of the front wheel connector 5 and the middle horizontal through holes of the second rigid sub-body 2 at the front end of the misaligned pipe-holding main body. The through holes at both ends of the first rigid link 3 at the last sub-section of the misaligned pipe-holding main body are hinged to the horizontal through holes of the support columns of the rear wheel connection bin 10 and the middle horizontal through holes of the first rigid sub-body 1 at the rear end of the misaligned pipe-holding main body, so as to prevent the first hub motor 7 and the second hub motor 13 from detaching from the wall surface when the robot climbs the pipe. And the second rigid link 4 is removed from the last sub-section of the misaligned pipe-holding main body to prevent it from interfering with the second hub motor 13.

[0067] Further, as Figure 6 shown, there are four through holes above the hollow body of the rear wheel connection bin 10, so that the wires of the first hub motor 7, the second hub motor 13, the wire winding motor 14, and the ultrasonic probe 19 can pass through and be connected to the circuit board in the rear wheel connection bin 10.

[0068] Further, the first hub motor 7 and the second hub motor 13 are wrapped with rubber layers on the outside, and the driven wheel 9 is wrapped with a rubber tire with asymmetric patterns on the outside to avoid wear, and at the same time increase the friction with the pipe surface to prevent the robot from slipping. The wire rope 16 is made of soft anti-twisting, wear-resistant and tensile-resistant nylon wire to better realize the pipe-holding adsorption movement of the robot.

[0069] Furthermore, the first rigid sub-body 1, the second rigid sub-body 2, the first rigid connecting rod 3, the second rigid connecting rod 4, the front-wheel connecting member 5, and the rear-wheel connecting chamber 10 are all made of rigid and lightweight materials to ensure the motion stability of the robot and reduce its weight. These parts are assembled and connected with round head pins and are offset, that is, the front-wheel connecting member 5, each sub-segment of the offset pipe-holding main body, and the rear-wheel connecting chamber 10 are not on the same straight line, so that the robot can form an offset pipe-holding shape.

[0070] The following details the design process of the multi-diameter offset pipe-holding wall-climbing robot for external pipeline ultrasonic testing provided by the present invention.

[0071] I. The offset design of the robot.

[0072] In the present invention, the front and rear sub-segments of the offset pipe-holding main body are offset-connected without structural interference hindering the cooperation, and it is necessary to satisfy t 2 ≤2t 1 , t 3 ≥2t 2 , and 2t 1 <t 3 ≤(T - 2t 1 ) / 2, where t 1 is the wall thickness on both sides of the rigid sub-body, t 2 is the thickness of the rigid connecting rod, t 3 is the width of each hollow area of the rigid sub-body, and T is the width of the rigid sub-body, as Figure 9 shown.

[0073] Preferably, as Figure 10 shown, t 2 = 2t 1 , t 3 = 2t 2 = 4t 1 , and T>2t 1 + 2t 3 , at this time, the first rigid connecting rod 3 of the front and rear sub-segments of the offset pipe-holding main body exactly fills the left hollow area of the rigid sub-body, and the second rigid connecting rod 4 exactly fills the right hollow area of the rigid sub-body, so that the front and rear sub-segments can be closely offset-connected to avoid lateral loosening and changing the offset distance between the front and rear sub-segments.

[0074] To prevent interference between the driven wheel units of the front and rear sub-segments of the offset pipe-holding main body when the robot is offset pipe-holding, it is necessary to satisfy t 4 <2t 1 , where t 4 is the thickness of the driven wheel.

[0075] II. Determine the minimum number of sub-segments of the offset pipe-holding main body according to the pipeline diameter.

[0076] To enable the robot to closely and stably hold onto the outer surface of the pipeline, the misaligned pipe-holding body should hold the outer pipeline at least one full circle to prevent the robot from falling off during movement. The number of sub-segments N of the misaligned pipe-holding body can be determined according to the pipeline diameter D. The larger the pipeline diameter or the more circles the robot holds the pipe (the more circles the robot holds the pipe, the more stable the adsorption movement of the robot on the outer surface of the pipeline), the more sub-segments the misaligned pipe-holding body has.

[0077] When the misaligned pipe-holding body holds the outer pipeline one full circle, as Figure 11 shown, at this time N = 14, the pipeline diameter D and the minimum number of sub-segments N of the misaligned pipe-holding body min (N min is an integer) satisfy Equation (1). Since the calculation result of N min may be a decimal, so use to replace N min :

[0078] (1)

[0079] where, H is the distance from the center of the transverse through-hole in the middle of the rigid body to the ground. As Figure 12 shown, at this time the robot is not bent and is placed flat on the ground. C is the center distance between the through-holes at both ends of the rigid link (the center distance between the transverse through-holes in the middle of the first rigid body of the front and rear sub-segments, that is, the center distance between the transverse through-holes in the middle of the second rigid body of the front and rear sub-segments).

[0080] When the pipeline diameter D is determined, can be calculated according to Equation (1) , and then perform ceiling operation on to obtain the minimum number of sub-segments N min . When it is required that the misaligned pipe-holding body holds the outer pipeline n circles, can multiply by n and perform ceiling operation to obtain the number of sub-segments N of the misaligned pipe-holding body.

[0081] III. Design the misaligned pipe-holding body according to the required range of the outer diameter of the pipeline to be detected, and determine the parameters of the misaligned pipe-holding body.

[0082] To enable the robot to closely and stably hold onto the outer surface of the pipeline, the misaligned pipe-holding body should hold the outer pipeline at least one full circle to prevent the robot from falling off during movement.

[0083] The robot has a minimum applicable pipeline diameter D min , and the maximum applicable pipeline diameter can be expanded by increasing the number of sub-segments of the misaligned pipe-holding body. Therefore, the pipeline diameter D applicable to the robot is D ≥ D min , and the robot can be designed according to the relationship between D min and the structural parameters of the robot.

[0084] First, when the robot misplaces and holds the pipe, the pipe diameter D, the distance h from the center of the lower transverse through-hole of the rigid sub-body to the ground (as shown in Figure 12 , at this time the robot is not bent and lies flat on the ground), the center distance L between the upper and lower transverse through-holes of the rigid sub-body, the angle between the straight line connecting the upper and lower transverse through-holes of the first rigid sub-body and the straight line connecting the upper and lower transverse through-holes of the second rigid sub-body in the same sub-segment, and the angle between the straight line connecting the upper and lower transverse through-holes of the second rigid sub-body and the straight line connecting the upper and lower transverse through-holes of the first rigid sub-body in the next sub-segment satisfy Equation (2) (when the robot misplaces and bends to hold the pipe, ):

[0085] (2)

[0086] Secondly, L, , and the center distance C between the through-holes at both ends of the rigid connecting rod satisfy Equation (3):

[0087] (3)

[0088] When the robot misplaces and holds the pipe, the bending degree depends on the outer diameter of the pipe. The smaller the outer diameter of the pipe, the greater the bending degree of the robot, the smaller , the greater . The minimum value of and the maximum value of are determined by the robot structure. Because when the robot continuously increases the bending degree, it will stop bending due to structural interference. At this time, the limit bending degree (the maximum bending degree) is reached, and , and at the same time, the minimum applicable pipe diameter of the robot is determined as D = D min .

[0089] Therefore, when designing the misaligned pipe-holding body of the robot, the outer shape of the rigid sub-body can be designed first, and the and and h when the robot reaches the limit bending degree can be determined. Then, according to the different outer diameters of various pipes to be detected, the range of the pipe diameter D applicable to the robot can be determined, that is, D ≥ D min , and D min can retain a certain margin, that is, it can be a little smaller than the smallest pipe diameter in the pipes to be detected. Then , D = D minSubstitute h and h into formula (2) to obtain the size L of the rigid subbody (of course, you can also design the rigid subbody shape and L first, and then calculate D = D using formula (2) min , and verify D min Is it less than or equal to the minimum pipe diameter in the pipe to be tested? If not, modify L until it is satisfied. , Substitute L and L into formula (3) to obtain the center distance C of the through holes at both ends of the rigid connecting rod.

[0090] And H can be obtained by formula (4) (at this time the robot is not bent and is placed flat on the ground, ,and The value of can be determined when the rigid subbody shape is well designed):

[0091] (4)

[0092] So D = D min , H and C are substituted into formula (1) to calculate , thereby determining the minimum number of sub-segments required for the robot to hold the smallest diameter pipe in a misaligned position .

[0093] In order to enable the dislocation pipe holding body to dislocation hold the outer pipe in a circle, it is only necessary to meet the requirement that the robot can hold the pipe with the smallest diameter in a circle without structural interference, that is, the minimum number of sub-segments required for the robot to dislocation hold the pipe with the smallest diameter and the thickness of the left and right sides of the rigid subbody t 1 and the width T of the rigid subbody satisfy equation (5):

[0094] (5)

[0095] This formula has a certain margin, combined with t 2 ≤2t 1 , t 3 ≥2t 2 and 2t 1 <t 3 ≤(T-2t 1 ) / 2 (preferably, t 2 =2t 1 , t 3 =2t 2 =4t 1 , and T>2t 1 +2t 3 ), the thickness of the left and right sides of the rigid sub-body can be designed and determined 1 , Rigid connecting rod thickness t 2 , the width t of each hollow area of ​​the rigid subbody 3 and the rigid subbody width T.

[0096] IV. Multi-probe layout, which is used to improve the detection efficiency, detection range, detection resolution, detection accuracy, detection applicability, detection flexibility, achieve multi-functional detection, reduce the overall detection cost, and reduce or eliminate blind spots.

[0097] Preferably, ultrasonic detection units can also be installed on the left and right sides of the first rigid sub-body and the second rigid sub-body of each sub-segment of the robot. Due to the misalignment between the two rigid sub-bodies of the sub-segment and the misalignment between each sub-segment, the ultrasonic probes can be diversely arranged to achieve large-range multi-region detection, or detect defects in the same region from different angles. For example, if the probes are to be arranged densely, ultrasonic probes can be installed on the same side of the first rigid sub-body and the second rigid sub-body of each sub-segment of the misaligned pipe-holding body. At this time, the lateral spacing of each ultrasonic probe is the wall thickness t on both sides of the rigid sub-body. 1 If the probes are to be arranged sparsely, ultrasonic probes can be uniformly installed on the same side of the first rigid sub-body or the second rigid sub-body every m sub-segments. At this time, the lateral spacing of each ultrasonic probe is (2m + 2)t. 1 Of course, the ultrasonic probes do not necessarily need to be arranged at equal intervals, nor do they necessarily need to be installed on the same side. The arrangement layout of the ultrasonic probes can be optimized through algorithms according to the detection object, detection requirements, ultrasonic probe characteristics, etc. For example, the ultrasonic probes can be installed densely on the first few sub-segments and sparsely on the last few sub-segments. Another example is that when only specific regions need to be detected within the coverage area of the robot's misaligned pipe-holding, ultrasonic probes can be installed on some sub-segments above or near these specific regions.

[0098] When it is necessary to increase the number of ultrasonic probes or the coverage area of the misaligned pipe-holding, the number of sub-segments N or the number of pipe-holding circles n of the misaligned pipe-holding body can be increased as required. In order to be able to install ultrasonic probes on the rigid sub-body and avoid structural interference during the robot's misaligned pipe-holding, Equation (5) is further rewritten as:

[0099] (6)

[0100] Where d is the lateral distance required for installing the ultrasonic probe.

[0101] In addition, according to different detection requirements, the characteristics of the ultrasonic probes can be selected. The multi-probe system of the robot can be composed of a variety of different ultrasonic probes, or multiple ultrasonic detection technologies can be integrated.

[0102] V. Motor control design.

[0103] Perform speed control on the first hub motor and the second hub motor to keep their speeds the same during the pipe-holding movement of the robot, so as to prevent damage caused by pulling the robot due to different speeds of the two.

[0104] The winding motor uses a servo motor, and during the robot's pipe-holding movement, the change in the servo motor torque is reflected by real-time monitoring of the change in the servo motor current. This is reflected in:

[0105] ① When the servo motor current increases, that is, the torque increases, it means that the robot encounters a raised obstacle such as rust or attachments. At this time, the winding motor is controlled in real time to release a certain length of rope to restore the torque to prevent excessive torque from damaging the robot and the winding motor. When the raised obstacle becomes smaller or the robot crosses the obstacle, the servo motor current decreases, and the winding motor is controlled in real time to tighten a certain length of rope to maintain the torque.

[0106] ② When the servo motor current becomes smaller, that is, the torque becomes smaller, it means that the robot encounters a recessed obstacle such as a pit. At this time, the winding motor is controlled in real time to tighten a certain length of rope to restore the torque to prevent the robot from detaching from the pipe surface and affecting the stable and uniform pipe-holding adsorption movement. When the recessed obstacle becomes smaller (for example, the pit becomes shallower) or the robot crosses the recessed obstacle, the servo motor current becomes larger, and the winding motor is controlled in real time to release a certain length of rope to maintain the torque.

[0107] 6. Design of driven wheel unit.

[0108] Preferably, in order to further simplify the robot, reduce energy consumption and save costs, the layout of the driven wheel units can be reasonably optimized, such as installing a driven wheel unit for each offset pipe-holding main body sub-segment to reduce the number of driven wheel units and reduce the resistance encountered by the robot during pipe-holding movement, thereby reducing the driving force required for the robot.

[0109] 7. Design of multiple robots holding adjacent pipes.

[0110] When the pipelines to be inspected are adjacent, in order to further improve the automation and operating efficiency of the robot, three or more multi-diameter dislocation pipe-holding wall-climbing robots for external pipeline ultrasonic inspection can be spliced ​​end to end to achieve the automatic movement of the spliced ​​robot from the current pipeline to the adjacent pipeline and hold it tightly. In order to achieve automatic reset and retention after the rope is lengthened when the robot is bent, a spring can be installed between the two adjacent holes in front and behind where the rope passes. At the same time, when the robot automatically resets and holds the state, the rope is tightened and the spring is in a compressed state, but the robot is balanced.

[0111] For example, Figure 13As shown, the first robot with the rear drive wheel unit removed, the second robot with the front drive wheel unit and rear drive wheel unit removed, and the third robot with the front drive wheel unit removed are spliced end to end with a dislocation to form the fourth robot. At this time, the wire winding motors of the first robot and the second robot are respectively fixed on their respective last sub-segments, and the wire rope of the second robot also passes through the bottom of the second rigid body of the last sub-segment of the first robot. The wire rope of the third robot also passes through the bottom of the second rigid body of the last sub-segment of the second robot. At the same time, no rigid connecting rod is assembled between the two sub-segments at the splicing joints of the first robot and the second robot, and the second robot and the third robot.

[0112] When the current pipeline is detected and the fourth robot needs to be moved to an adjacent pipeline, first, the wire winding motor of the first robot is used to lengthen its own wire rope, so that the first robot automatically resets to a straight state under the action of the spring and remains in this state. Then, the wire winding motor of the second robot is controlled to lengthen its wire rope, so that the second robot automatically resets to a straight state under the action of the spring and remains in this state. Finally, the side of the fully straightened first robot with the driven wheel unit approaches the adjacent pipeline, as Figure 14 shown; then, the wire winding motor of the first robot is used to contract its own wire rope but not tighten it, so that the first robot can hold on to the adjacent pipeline. Then, the wire winding motor of the third robot is controlled to appropriately lengthen its wire rope and it still holds on to the current pipeline. At the same time, the wire winding motor of the first robot is controlled to tighten its own wire rope to hold the adjacent pipeline tightly. Then, the wire winding motor of the third robot is continuously controlled to lengthen its wire rope, so that the third robot automatically resets to a straight state under the action of the spring and remains in this state, as Figure 15 、 Figure 16 shown; finally, the wire winding motors of the second robot and the third robot are sequentially controlled to tighten their respective wire ropes, so that the second robot and the third robot also hold the adjacent pipeline tightly, as Figure 17 shown.

[0113] In this process, the second hub motor of the rear drive wheel unit of the third robot and the first hub motor of the front drive wheel unit of the first robot need to be flexibly controlled, so that the fourth robot performs a pipe climbing movement on the current pipeline or the adjacent pipeline to cooperate with the pipe detachment and pipe holding of the robot, thereby avoiding collisions between the robot and the pipeline when it gradually straightens or bends and reverse bending, and also avoiding the situation that the first robot cannot hold the adjacent pipeline because the number of sub-segments of the adjacent pipeline section it approaches is too small. In addition, in this process, the wire ropes of the first robot, the second robot, and the third robot are always in a tensioned state, and the first robot, the second robot, and the third robot do not necessarily need to be fully reset to a straight state, but can also be reset to a slightly bent state and remain in this state. And the misaligned pipe holding body of the second robot needs to be long enough to ensure that there are enough sub-segments to hold the adjacent pipeline when the first robot approaches the adjacent pipeline.

[0114] The operation process of the multi-diameter misaligned pipe-holding wall-climbing robot for external pipeline ultrasonic detection provided by the present invention is as follows:

[0115] Driven by the wire-winding motor 14, the wire-winding reel 15 rotates with the rotating shaft of the wire-winding motor 14 to tighten the wire rope 16. Since the rigid sub-body, the rigid connecting rod, the front-wheel connecting member 5 and the rear-wheel connecting bin 10 are hinged and misaligned through pins, they can rotate relative to each other at the hinge joints. Thus, under the action of the wire rope 16, the robot bends misaligned towards the side of the wire rope 16, and the tighter the wire rope 16 is wound, the greater the degree of misaligned bending of the robot.

[0116] More specifically, first, determine the ultrasonic probe and its arrangement layout according to the detection requirements, and design the misaligned pipe-holding main body of the robot. First, design the shape of the rigid sub-body, and then determine the parameters of the rigid sub-body and the rigid connecting rod in the misaligned pipe-holding main body according to the outer diameter range of the pipeline to be detected and the installation space of the ultrasonic probe. Then, design the front drive wheel unit, the driven wheel unit, the rear drive wheel unit, the pipe-holding drive unit and the ultrasonic detection unit. Then, determine the number of sub-segments N of the misaligned pipe-holding main body according to the diameter of the pipeline to be detected and the detection requirements at present, and the layout of the driven wheel unit can also be reasonably optimized. Finally, complete the manufacturing and assembly of the robot.

[0117] When performing misaligned pipe-holding and circumferential pipe-climbing detection, tools such as drones can be used to grasp the end of the robot in the straight state and transport the robot near the pipeline to be detected, and make the side of the robot with the driven wheel unit close to the pipeline. Then, control the drive wire-winding motor 14 through the circuit board in the rear-wheel connecting bin 10 to tighten the wire rope 16, gradually increase the degree of misaligned bending of the robot, and make the robot start to hold the pipe. At the same time, control the tool to cooperate with the pipe-holding movement of the robot, and release the robot at the appropriate time. Finally, make the first hub motor 7, the second hub motor 13 and multiple driven wheels 9 of the robot closely fit the outer surface of the pipeline. The tighter the wire rope 16 is wound, the greater the degree of fit between the robot and the outer surface of the pipeline, the more stable the robot's pipe-holding adsorption, and the more stable the circumferential pipe-climbing movement. Then, control the first hub motor 7, the second hub motor 13 and the ultrasonic probe 19 through the circuit board in the rear-wheel connecting bin 10, so that the robot performs stable circumferential pipe-climbing movement while performing ultrasonic detection on the pipeline. After detecting the current area, stop the movement and ultrasonic detection of the robot, loosen the wire rope 16 but the robot still holds the pipe. At this time, the robot can be moved to other areas to be detected of the current detected pipeline through tools, and then make the robot hold the pipe tightly to perform circumferential pipe-climbing detection.

[0118] After the inspection is completed, the robot's movement and ultrasonic inspection are stopped, the wire rope 16 is loosened, the robot is retracted, and the robot can be split into multiple parts according to different numbers of sub-segments for storage, transportation, and subsequent assembly and use. When the number of sub-segments N of the staggered pipe holding body required in the future changes, the sub-segments can be easily increased or decreased after the wire rope 16 is removed, and the driven wheel unit can also be easily increased or decreased.

[0119] The above is only a preferred embodiment of the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A multi-diameter dislocated pipe-holding wall-climbing robot for external pipeline ultrasonic testing, characterized in that: It includes a dislocated pipe holding body, a front driving wheel unit, a driven wheel unit, a rear driving wheel unit, a pipe holding drive unit and an ultrasonic detection unit; The staggered pipe holding body is composed of a plurality of sub-segments connected in a staggered manner in sequence, and each sub-segment includes a first rigid sub-body, a second rigid sub-body, a first rigid connecting rod, and a second rigid connecting rod; the first rigid sub-body and the second rigid sub-body are arranged in a staggered mirror image and are hinged to form an inverted V-shaped structure of the sub-segment; the first rigid connecting rod and the second rigid connecting rod stagger the inverted V-shaped structures of the front and rear sub-segments, and the two inverted V-shaped structures are staggered and hinged to form an inverted W-shaped structure through adjacent sub-bodies; The front driving wheel unit has a first wheel hub motor, which is staggered and hinged with the first rigid sub-body at the front end of the staggered tube holding body; the rear driving wheel unit has a second wheel hub motor, which is staggered and hinged with the second rigid sub-body at the rear end of the staggered tube holding body; the driven wheel unit is hinged at the bottom of the second rigid sub-body; The pipe holding drive unit comprises a winding motor, a winding drum and a wire rope; the winding motor is fixed on the rear driving wheel unit, the winding drum is fixed on the rotating shaft of the winding motor, one end of the wire rope is fixed on the winding drum, and the other end passes through the rear driving wheel unit, each sub-segment of the dislocated pipe holding body and the bottom of the front driving wheel unit in sequence, and then passes back to the winding drum in sequence and is fixed; The ultrasonic detection unit is fixed on the front driving wheel unit, and ultrasonic detection of the external pipeline is realized by an ultrasonic probe; By driving the winding motor to rotate the winding drum to tighten the rope, the robot is bent toward one side of the rope and tightly adheres to the outer surface of the pipe; by controlling the two hub motors, the robot is allowed to climb the pipe in a circumferential direction.

2. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 1 is characterized in that: The first rigid sub-body is a frame-type structure, with a concave structure at the top and bottom, equal wall thickness on the left and right sides, and transverse through holes at the upper and lower ends of the left and right sides, a vertical support column is provided in the middle, dividing the first rigid sub-body into left and right hollow areas, and transverse through holes are provided in the middle of the left and right sides of the first rigid sub-body and the middle of the support column; the second rigid sub-body is hinged to the first rigid sub-body through the upper transverse through holes on the left and right sides, the right inner wall of the first rigid sub-body is in contact with the right outer wall of the second rigid sub-body, and the left outer wall of the first rigid sub-body is in contact with the left inner wall of the second rigid sub-body, and the two are laterally staggered by a distance of wall thickness.

3. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 2 is characterized in that: The first rigid link has through holes at both ends, which are hinged to the middle transverse through holes of the first rigid sub-body of the front and rear sub-segments, and are located in the left hollow area of ​​the first rigid sub-body and the second rigid sub-body; the second rigid link has through holes at both ends, which are hinged to the middle transverse through holes of the second rigid sub-body of the front and rear sub-segments, and are located in the right hollow area of ​​the first rigid sub-body and the second rigid sub-body.

4. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 3 is characterized in that: The front drive wheel unit includes a front wheel connecting member, which has a U-shaped structure lying flat forward. Transverse through holes are provided at the front ends on both left and right sides for a first threaded fixed shaft for fixedly installing a first hub motor. A transverse through hole is provided at the lower end of the part connecting the rear ends on both left and right sides in the U-shaped structure, and is hinged to the lower transverse through holes on both left and right sides of the first rigid sub-body at the frontmost end of the misaligned pipe-holding main body; the part connecting the left and right sides in the U-shaped structure is hollowed out from both left and right sides to the middle to form a vertical support column. A transverse through hole is provided in the middle of the support column. By adding a second rigid connecting rod, the through holes at both ends thereof are respectively hinged to the transverse through hole of the support column of the front wheel connecting member and the middle transverse through hole of the second rigid sub-body at the frontmost end of the misaligned pipe-holding main body.

5. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 3 is characterized in that: The rear drive wheel unit includes a rear wheel connecting bin, which is composed of an L-shaped structure and a U-shaped structure lying flat backward; transverse through holes are provided at the rear ends on both left and right sides of the U-shaped structure for a second threaded fixed shaft for fixedly installing a second hub motor. A transverse through hole is provided at the lower end of the part connecting the front ends on both left and right sides in the U-shaped structure, and is hinged to the lower transverse through holes on both left and right sides of the second rigid sub-body at the rearmost end of the misaligned pipe-holding main body; the L-shaped structure is a hollow bin body arranged above and behind the U-shaped structure for placing a circuit board; the part connecting the left and right sides in the U-shaped structure is hollowed out from both left and right sides to the middle to form a vertical support column. A transverse through hole is provided in the middle of the support column. The through holes at both ends of the first rigid connecting rod at the rearmost end of the misaligned pipe-holding main body are respectively hinged to the transverse through hole of the support column of the rear wheel connecting bin and the middle transverse through hole of the first rigid sub-body at the rearmost end of the misaligned pipe-holding main body, and the second rigid connecting rod is removed from the sub-segment at the rearmost end of the misaligned pipe-holding main body.

6. The multi-diameter dislocated pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 3 is characterized in that: The front and rear sub-segments of the misaligned pipe-holding main body are misaligned and connected without structural interference, and need to satisfy t2 ≤ 2t1, t3 ≥ 2t2, and 2t1 < t3 ≤ (T - 2t1) / 2, where t1 is the wall thickness on both left and right sides of the rigid sub-body, t2 is the thickness of the rigid connecting rod, t3 is the width of each hollow area of the rigid sub-body, and T is the width of the rigid sub-body; there is no structural interference between the driven wheel units of the front and rear sub-segments of the misaligned pipe-holding main body when the robot misaligns and holds the pipe, and it needs to satisfy t4 < 2t1, where t4 is the thickness of the driven wheel.

7. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 6 is characterized in that: The minimum number of sub-segments of the dislocation pipe holding body is determined according to the pipe diameter. The dislocation pipe holding body holds the outer pipe for at least one circle. When the dislocation pipe holding body holds the outer pipe for one circle, the pipe diameter D and the minimum number of sub-segments N of the dislocation pipe holding body are equal. min satisfy , where H is the distance from the center of the horizontal through hole in the middle of the rigid sub-body to the ground when the robot is placed flat on the ground, and C is the center distance of the through holes at both ends of the rigid connecting rod. It is an intermediate parameter. When the pipe diameter D is determined, it is first calculated , then Round up to get the minimum number of sub-segments N min ; When the staggered pipe holding body is required to hold the outer pipe n times, Multiply by n and round up to get the number N of sub-segments of the misaligned pipe body.

8. The multi-diameter dislocated pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 7 is characterized in that: The parameter design of the misaligned pipe-holding main body is specifically as follows: The robot has a minimum applicable pipe diameter D min , the robot is suitable for pipe diameter D ≥ D min ; When the robot holds the pipe in a misaligned position, the pipe diameter D, the distance h from the center of the transverse through hole at the lower end of the rigid sub-body to the ground when the robot is placed flat on the ground, the center distance L between the transverse through hole at the upper end and the transverse through hole at the lower end of the rigid sub-body, and the angle between the straight line connecting the transverse through hole at the upper end and the transverse through hole at the lower end of the first rigid sub-body and the straight line connecting the transverse through hole at the upper end and the transverse through hole at the lower end of the second rigid sub-body in the same sub-segment , the angle between the straight line connecting the upper and lower transverse through holes of the second rigid sub-body and the straight line connecting the upper and lower transverse through holes of the first rigid sub-body of the next sub-segment Satisfying formula (1): (1) L. , The center distance C of the through holes at both ends of the rigid connecting rod satisfies formula (2): (2) The degree of bending when the robot holds the pipe in a misaligned position depends on the outer diameter of the pipe. Minimum value of and The maximum value of Determined by the structure of the robot, when the robot reaches the limit of bending, , , D=D min ; First design the rigid sub-body shape and determine when the robot reaches the limit bending degree. and And h, and then determine the range of pipe diameter D applicable to the robot according to the different outer diameters of the various pipes to be detected. , D=D min Substitute and h into formula (1) to obtain L; or, first design the rigid subbody shape and L, and then calculate D = D using formula (1) min , and verify D min Is it less than or equal to the minimum pipe diameter to be tested? If not, modify L until it is satisfied. , Substitute C and L into formula (2) to obtain C; the calculation formula for H is , where the robot is flat on the ground , The value of is determined when the rigid subbody shape is designed; According to D=D min , H and C to calculate the minimum number of sub-segments required for the robot to hold the minimum diameter pipe in a misaligned manner , , t1 and T satisfy ; Then, combined with t2≤2t1, t3≥2t2 and 2t1<t3≤(T-2t1) / 2, determine the wall thickness t1 on the left and right sides of the rigid sub-body, the thickness t2 of the rigid connecting rod, the width t3 of each hollow area of ​​the rigid sub-body and the width T of the rigid sub-body.

9. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 1 is characterized in that: The wire winding motor adopts a servo motor, and the change of the torque of the servo motor is reflected by real-time monitoring of the change of the current of the servo motor: When the current of the servo motor increases, it indicates that the robot encounters a convex obstacle, and the wire winding motor is controlled to release the wire rope to restore the torque. When the convex obstacle becomes smaller or the robot crosses the convex obstacle, the current of the servo motor decreases, and the wire winding motor is controlled to tighten the wire rope to maintain the torque; When the current of the servo motor decreases, it indicates that the robot encounters a concave obstacle, and the wire winding motor is controlled to tighten the wire rope to restore the torque. When the concave obstacle becomes smaller or the robot crosses the concave obstacle, the current of the servo motor increases, and the wire winding motor is controlled to release the wire rope to maintain the torque.

10. The multi-diameter dislocation pipe-holding wall-climbing robot for external pipeline ultrasonic testing according to claim 1, characterized in that: By splicing three or more robots head to tail in a staggered manner, the spliced ​​robots can automatically move from the current pipe to the adjacent pipe and hold it tightly; by installing a spring between the two adjacent holes in front and behind where the wire rope passes, the robot can automatically reset and hold the wire rope after it is lengthened when it is bent; During the splicing process, the robot at the front end removes the rear drive wheel unit and fixes the winding motor on the last sub-segment, the robot in the middle part removes the front drive wheel unit and the rear drive wheel unit and fixes the winding motor on the last sub-segment, and the robot at the rear end removes the front drive wheel unit. The rope of the rear robot passes through the bottom of the second rigid sub-body of the last sub-segment of the front robot, and no rigid connecting rod is installed between the two sub-segments at the splicing point.

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