Variable-diameter supporting type pipeline robot based on Mecanum wheels and working method of variable-diameter supporting type pipeline robot

Abstract

The invention discloses a variable-diameter supporting type pipeline robot based on Mecanum wheels and a working method of the variable-diameter supporting type pipeline robot. The variable-diameter supporting type pipeline robot comprises a variable-diameter supporting module, a driving module and an overall frame module. The driving module provided with the left-handed Mecanum wheel is fixed on a front fork at the tail end of the variable-diameter supporting module to form a front supporting structure; the driving module provided with the right-handed Mecanum wheel is fixed on a front fork at the tail end of the variable-diameter supporting module to form a rear supporting structure; the front supporting structure is fixed on a middle plate at the middle front part of the integral frame module; and the rear supporting structure is fixed on a tail plate at the middle rear part of the integral frame module. The robot can adapt to a large-range working pipe diameter, meanwhile, supporting force self-adaptive compensation is carried out, and the phenomenon that the robot slips relative to the inner wall of a pipeline is reduced; the driving module provided with the Mecanum wheels enables the robot to achieve axial translation, circumferential rotation and oblique climbing motion in a pipeline. And the quality inspection and maintenance efficiency of the pipeline is improved.

Description

Technical Field

[0001] The present invention belongs to the field of pipeline robots, and specifically relates to a variable-diameter support type pipeline robot based on Mecanum wheels and its working method. Background Art

[0002] At present, as one of the transportation media, pipelines play an indispensable role in daily life. Pipelines can transport both gases and liquids, etc. Therefore, the sealing and anti-corrosion of pipelines are very important. However, during the pipeline welding and anti-corrosion process, traditional manual welding has the problem of low welding efficiency when dealing with medium and small pipelines. As an alternative to manual work, pipeline robots have been used to a certain extent in the field of internal pipeline operations. However, existing pipeline robots have problems such as poor flexibility, weak adaptability, and operation dead angles.

[0003] Guo Zhongfeng et al. applied for a pipeline robot with active rotation and obstacle avoidance on November 29, 2019, with the publication number CN111120775A. This pipeline inspection robot adopts a modular design and mainly consists of an overall frame module, a drive and transmission module I, a rear support and travel module, a drive and transmission module II, and a front support and rotation module. The overall frame module serves as an external support and protection structure. The drive and transmission module I provides power for pipeline travel through a worm-gear mechanism. The rear support and travel module uses a spring-tensioned synchronous pulley to achieve passive variable diameter and maintain transmission stability; the drive and transmission module II uses a planetary gear train to provide rotational power. The front support and rotation module combines Mecanum wheels and support springs to achieve active rotation and obstacle avoidance, and ensures normal meshing during variable diameter through fixed connecting rods and a planetary gear train. Although this pipeline robot can walk smoothly in the pipeline through active rotation and obstacle avoidance, its passive variable diameter ability achieved through a spring-tensioning mechanism is only applicable to pipelines with a diameter of 148 - 152 mm and cannot actively cope with a working environment with a large range of variable diameters. Its transmission between planetary gear trains provides driving force for the transposition. As the driving force execution unit, the Mecanum wheels slip against each other during movement, causing unnecessary slippage.

[0004] Liu Shanzeng et al. applied for a pipeline robot with adaptive pipe diameter change on November 24, 2020, with the publication number CN112325050A. It adopts a modular rack leg unit design, and each unit includes a rack and at least three circumferentially evenly distributed driving legs. The driving legs adopt a symmetric connecting rod-gear transmission structure: the support is fixed on the rack, and synchronous reverse rotation is achieved through mutually meshing Gear 1 and Gear 2, and they are respectively connected to Upper Connecting Rod 1 and Upper Connecting Rod 2; two groups of connecting rod mechanisms (Upper Connecting Rod 1 / Lower Connecting Rod 1 and Upper Connecting Rod 2 / Lower Connecting Rod 2) form a parallelogram four-bar structure through an intermediate shaft and a pin shaft, and a belt drive system and wheels are installed at the end. Power is transmitted from the motor to the wheels through two-stage synchronous belt drives of a belt pulley and a double belt pulley, and a tension spring is connected to the two sides of the connecting rod to maintain adaptive tension. Adjacent rack units are flexibly connected, and the pipe diameter adaptability is achieved through the coordinated telescoping of the connecting rod mechanism. Gear meshing ensures the synchronous movement of multiple legs, and the belt drive system ensures stable power transmission to each driving wheel. This pipeline robot enables the pipeline robot to actively adapt to pipelines with a large range of pipe diameter changes through the driving legs of the scissor-type variable diameter structure. However, due to the limitation of the movement degrees of freedom of the driving legs, the rotation movement along the pipeline axis cannot be achieved, resulting in operation dead corners and affecting the operation range. Summary of the Invention

[0006] In view of the problems of insufficient adaptability of the current pipeline robot to the working pipe diameter, insufficient flexibility, and the existence of operation dead corners, the present invention provides a variable-diameter support type pipeline robot based on Mecanum wheels and its working method. Through the adjustment of the variable-diameter support module based on the support type variable diameter structure, the robot can adapt to the pipe inner diameter within a certain range. Through the driving module equipped with Mecanum wheels, the robot can achieve flexible attitude transformation in the pipeline and perform all-round operations on various positions in the pipeline.

[0007] To achieve the above object, the technical solutions provided by the present invention are as follows: A variable-diameter support type pipeline robot based on Mecanum wheels, characterized in that it includes a variable-diameter support module, a driving module, and an overall frame module; A number of groups of variable-diameter support modules are evenly distributed in the circumferential direction of the overall frame module. A number of groups of variable-diameter support modules evenly distributed in the circumferential direction form a set of support structures, and at least two sets of support structures are provided in the length direction of the overall frame module; Each group of variable-diameter support modules at least includes a swing rod and an electric push rod for driving the swing rod to swing, and the driving module is installed at the free end of the swing rod; The driving module is a Mecanum wheel driven by a motor. The rotation directions of the Mecanum wheels on the same set of support structures are the same, and the rotation directions of the Mecanum wheels on different sets of support structures are different.

[0008] Further, the above-mentioned overall frame module is composed of 1 head plate, 4 push rod support plates, 1 middle plate, 3 support positioning plates, and 1 tail plate; the 3 support positioning plates are circumferentially distributed with a 120° interval between each other; the head plate, push rod support plates, middle plate, and tail plate are sequentially fixed to the positioning holes of the support positioning plates, and are connected to the support positioning plates by M8 screws.

[0009] Further, three variable-diameter support modules are installed at a 120° interval radially between the push rod support plate and the middle plate to form a set of support structures, namely the front support structure; three variable-diameter support modules are installed at a 120° interval radially between the push rod support plate and the tail plate to form a set of support structures, namely the rear support structure; the push rod support plate and the middle plate are components of the overall frame module and are fixedly connected to the support positioning plates.

[0010] Further, the above-mentioned variable-diameter support module includes 1 swing rod connecting piece, 1 driving swing rod, 1 supporting swing rod, 1 front fork, 4 front fork shafts, 8 D10 flange bearings, 6 D15 flange bearings, 2 swing rod shafts, 1 push rod shaft, 1 push rod connecting piece, 1 electric push rod, and 1 push rod mounting seat; the push rod mounting seat is connected to the push rod support plate by screws, the swing rod connecting piece is connected to the middle plate by screws, and the front end of the push rod support plate and the electric push rod are connected through the push rod mounting seat; the front end of the driving swing rod is connected to the swing rod connecting piece through a swing rod shaft; the front end of the supporting swing rod is connected to the swing rod connecting piece through a swing rod shaft, and the swing rod shaft is installed on the swing rod connecting piece through a D15 flange bearing; the rear end of the driving swing rod and the front fork are connected through a front fork shaft, the rear end of the supporting swing rod and the front fork are connected through a front fork shaft, and the driving swing rod and the supporting swing rod form a parallel double swing rod structure; the front fork shaft is installed on the front fork through a D10 flange bearing, the front end of the electric push rod is installed on the push rod mounting seat, the rear end of the electric push rod is connected to the driving swing rod through a push rod shaft, and the push rod shaft is connected to the driving swing rod through a D15 flange bearing.

[0011] Further, the above-mentioned driving module includes 1 left-handed Mecanum wheel or 1 right-handed Mecanum wheel, Mecanum wheel flange one, 1 Mecanum wheel flange two, 1 driving coded motor, and 1 motor support frame; Mecanum wheel flange one and Mecanum wheel flange two are respectively fixed on both sides of the left-handed Mecanum wheel by bolts and nuts, Mecanum wheel flange two is equipped with a coupling and is connected to the rotating shaft of the driving coded motor through this coupling, the driving coded motor is fixed to the motor support frame by screws, and the motor support frame is fixed to the front fork by bolts and nuts.

[0012] Further, the front support structure and the rear support structure provide support for the main body of the variable-diameter support type pipeline robot based on Mecanum wheels. The front support structure includes: 3 variable-diameter support modules and 3 Mecanum wheel drive modules with left-handed Mecanum wheels; the Mecanum wheel drive modules with left-handed Mecanum wheels are respectively installed on the front forks at the ends of the variable-diameter support modules and are installed on the middle plate at intervals of 120° from each other; the rear support structure includes: 3 variable-diameter support modules and 3 Mecanum wheel drive modules with right-handed Mecanum wheels; the Mecanum wheel drive modules with right-handed Mecanum wheels are respectively installed on the front forks at the ends of the variable-diameter support modules and are installed on the tail plate at intervals of 120° from each other.

[0013] The working method of the variable-diameter support type pipeline robot based on Mecanum wheels of the present invention (1) The pipeline robot enters the pipeline working environment. The motor of the electric push rod of the variable-diameter support module rotates to drive the electric push rod to extend. Since the two ends of the electric push rod are respectively fixed with the push rod support plate and the driving swing rod, the thrust generated by the extension of the electric push rod provides torque for the driving swing rod to rotate around the swing rod axis. Due to the parallel double swing rod structure, while the parallel driving swing rod and the supporting swing rod rotate around the swing rod axis respectively, the front fork always maintains a parallel posture with the inner wall of the pipeline and rotates around the front fork axis; (2) The drive module installed on the front fork is affected by the rotational torque of the driving swing rod, and the Mecanum wheels of the drive module generate support force and frictional force with the inner wall of the pipeline; (3) The 6 variable-diameter support modules installed on the fuselage are all deployed according to the above steps (1) and (2); (4) When the support force and frictional force generated between the Mecanum wheels and the pipe wall are sufficient, the motor of the electric push rod stops rotating and self-locks. At this time, the drive coding motor of the drive module starts and drives the Mecanum wheels to rotate through the coupling; (5) Since the drive modules of the front support structure are installed with left-handed Mecanum wheels and the drive modules of the rear support structure are installed with right-handed Mecanum wheels, by controlling the rotation speed and steering of the left-handed Mecanum wheels and the right-handed Mecanum wheels, the pipeline robot can achieve flexible attitude transformation in the pipeline.

[0014] When moving forward translationally along the pipeline, the Mecanum wheels of the drive modules installed on the front forks of the 3 variable-diameter support modules included in the front support structure rotate in the forward direction; the Mecanum wheels of the drive modules installed on the front forks of the 3 variable-diameter support modules included in the rear support structure rotate in the reverse direction; When rotating clockwise along the pipeline axis, the Mecanum wheels of the drive modules installed on the front forks of the 3 variable-diameter support modules included in the front support structure rotate in the forward direction; the Mecanum wheels of the drive modules installed on the front forks of the 3 variable-diameter support modules included in the rear support structure rotate in the forward direction; When rotating counterclockwise along the pipeline axis, the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the front support structure turn in the reverse direction; the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the rear support structure turn in the reverse direction.

[0015] The present invention can meet the operation requirements in complex industrial pipelines such as petrochemical pipelines and urban utility tunnels. It innovatively adopts Mecanum wheels in cooperation with a support type variable-diameter mechanism. The support type variable-diameter mechanism enables the pipeline robot to adapt to a wide range of working pipe diameters while performing self-adaptive compensation of the support force, reducing the slipping phenomenon of the robot relative to the inner wall of the pipeline; the drive modules equipped with Mecanum wheels enable the robot to achieve axial translation, circumferential rotation, and oblique climbing movements in the pipeline; this robot makes up for the shortcomings that it is difficult for humans to operate in the pipeline, and improves the quality inspection and maintenance efficiency of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an isometric schematic view of the overall structure of an embodiment of the present invention; Figure 2 is an isometric view of the variable-diameter support module of an embodiment of the present invention; Figure 3 is an isometric view of the front support structure of an embodiment of the present invention; Figure 4 is an isometric view of the rear support structure of an embodiment of the present invention; Figure 5 is an isometric view of the front drive module of an embodiment of the present invention; Figure 6 is an isometric view of the rear drive module of an embodiment of the present invention; Figure 7 is an isometric view of the overall frame module of an embodiment of the present invention; Figure 8 is a diagram showing the steering of the Mecanum wheels of each drive module when the present invention moves forward axially along the pipeline; Figure 9 is a diagram showing the steering of the Mecanum wheels of each drive module when the present invention rotates counterclockwise around the pipeline axis; Figure 10 is a diagram showing the steering of the Mecanum wheels of each drive module when the present invention rotates clockwise around the pipeline axis; Figure 11 is a working flow chart of an embodiment of the present invention; In the figure, there are a variable-diameter support module 100, a variable-diameter support module 100-F located in the front support structure, a variable-diameter support module 100-R located in the rear support structure, a drive module 200, a front drive module 200-L, a rear drive module 200-R, an overall frame module 300, a swing rod connecting piece 101, a drive swing rod 102, a support swing rod 103, a front fork 104, a front fork shaft 105, a D10 flange bearing 106, a D15 flange bearing 107, a swing rod shaft 108, a push rod shaft 109, a push rod connecting piece 110, an electric push rod 111, a push rod mounting seat 112, a left-handed Mecanum wheel 201, a right-handed Mecanum wheel 202, a Mecanum wheel flange one 203, a Mecanum wheel flange two 204, a drive coded motor 205, a motor support frame 206, a head plate 301, a push rod support plate 302, a middle plate 303, a support positioning plate 304, a tail plate 305, and an M8 screw 306. Detailed implementation manners

[0017] The present invention provides a variable-diameter support type pipeline robot based on Mecanum wheels. The structure of the variable-diameter support type pipeline robot based on Mecanum wheels is as Figures 1 - 7 shown. The variable-diameter support type pipeline robot based on Mecanum wheels includes a variable-diameter support module 100, a drive module 200, and an overall frame module 300.

[0018] There are 3 - 5 groups of variable-diameter support modules 100 evenly distributed in the circumferential direction of the overall frame module 300. The 3 - 5 groups of variable-diameter support modules 100 evenly distributed in the circumferential direction form a group of support structures (such as a front support structure and a rear support structure). There are two groups, three groups, or four groups of support structures in the length direction of the overall frame module 300; each group of variable-diameter support modules 100 at least includes a swing rod and an electric push rod for driving the swing rod to swing. The drive module 200 is installed at the free end of the swing rod; The drive module 200 is a Mecanum wheel driven by a motor. The rotation directions of the 3 - 5 Mecanum wheels on the same group of support structures are the same, and the rotation directions of the Mecanum wheels on different groups of support structures are different (that is, when there are two groups of support structures, the rotation directions of the Mecanum wheels on the two groups of support structures are different; when there are three groups of support structures, the rotation directions of the Mecanum wheels on two groups of support structures are the same, and the other group is different from the first two groups; when there are four groups of support structures, the rotation directions of the Mecanum wheels on every two support structures are the same).

[0019] Among them, the overall frame module is located outside the entire pipeline robot and provides positioning and support for other modules. The overall frame module consists of 3 support and positioning plates 304, 1 head plate 301, 1 middle plate 303, and 1 tail plate 305. The 3 positioning support plates are distributed at intervals of 120°. The head plate 301, middle plate 303, and tail plate 305 are sequentially installed in the positioning holes of the support and positioning plates 304 and fixed with M8 screws 306. The front support structure is installed in the first half of the entire pipeline robot, and the rear support structure is located in the second half of the entire pipeline robot. The front support structure and the rear support structure provide support for the pipe diameter adaptability of the robot. The front support structure includes 3 variable-diameter support modules 100-F, 3 drive modules 200-L with left-handed Mecanum wheels, 2 push rod support plates 302, and 1 middle plate 303. The 3 variable-diameter support modules 100-F are arranged at intervals of 120° and fixed to the middle plate 303 and the push rod support plates 302 by screws. The rear support structure includes 3 variable-diameter support modules 100-R, 3 drive modules 200-R with right-handed Mecanum wheels, 2 push rod support plates 302, and 1 tail plate 305. The 3 variable-diameter support modules 100-R are arranged at intervals of 120° and fixed to the tail plate 305 and the push rod support plates 302 by screws.

[0020] The variable-diameter support module 100 consists of 1 swing rod connecting piece 101, 1 driving swing rod 102, 1 supporting swing rod 103, 1 front fork 104, 1 electric push rod 111, 1 push rod mounting seat 112, 2 swing rod shafts 108, 1 push rod shaft 109, 4 front fork shafts 105, 8 D10 flange bearings 106, and 6 D15 flange bearings 107; the swing rod connecting piece 101 and the middle plate 303 are fixed by M8 screws, and each push rod mounting seat 112 and the two push rod support plates 302 are respectively fixed by two M8 screws; the driving swing rod 102, the supporting swing rod 103, and the swing rod connecting piece 101 are respectively fixed by a swing rod shaft 108. The driving swing rod 102 and the supporting swing rod 103 are installed facing each other to form a parallel double swing rod structure. The swing rod shaft 108 and the swing rod connecting piece 101 are fixed by two D15 flange bearings 107 and axially positioned by nuts. The driving swing rod 102, the supporting swing rod 103, and the front fork 104 are respectively hinged and fixed by front fork shafts 105. The front fork 104 and each front fork shaft 105 are fixed by D10 flange bearings 106 and axially positioned by nuts and circlips.

[0021] The free end of the telescopic rod of the driving swing rod 102 and the electric push rod 111 is fixedly connected by hinging through a push rod shaft 109. The free end of the telescopic rod of the electric push rod 111 and the push rod shaft 109 are fixed through a push rod connecting piece 110, and axial positioning is achieved through a nut and a circlip; the front fork 104 and the first Mecanum wheel flange 203 are connected through a bearing and axially fixed through a circlip; the first Mecanum wheel flange 203 is connected and fixed to the left-handed Mecanum wheel 202 through a nut, the left-handed Mecanum wheel 202 is connected and fixed to the second Mecanum wheel flange 204 through a nut, the second Mecanum wheel flange 204 is connected to the driving coded motor 205 through a coupling of the second Mecanum wheel flange 204, the driving coded motor 205 is connected to the motor support frame 206 through bolts. The first Mecanum wheel flange 203, the left-handed Mecanum wheel 202, the second Mecanum wheel flange 204, the driving coded motor 205, and the motor support frame 206 together form the front drive module 200-L, and the motor support frame 206 is connected to the front fork 104 through bolts; the front fork 104 and the first Mecanum wheel flange 203 are connected through a bearing and axially fixed through a circlip.

[0022] The first Mecanum wheel flange 203 is connected and fixed to the right-handed Mecanum wheel 202 through a nut, the right-handed Mecanum wheel 202 is fixed to the second Mecanum wheel flange 204 through a nut, the second Mecanum wheel flange 204 is connected to the driving coded motor 205 through a coupling of the second Mecanum wheel flange 204, the driving coded motor 205 is connected to the motor support frame 206 through bolts. The first Mecanum wheel flange 203, the right-handed Mecanum wheel 202, the second Mecanum wheel flange 204, the driving coded motor 205, and the motor support frame 206 together form the rear drive module 200-R, and the motor support frame 206 is connected to the front fork 104 through bolts.

[0023] The variable-diameter supported pipeline robot based on Mecanum wheels of the present invention is provided with a variable-diameter support module. This robot has the ability to adapt to working pipe diameters in the range of DN450 to DN800, and can achieve flexible posture transformation inside the pipeline and perform all-round operations inside the pipeline.

[0024] The working method of the variable-diameter supported pipeline robot based on Mecanum wheels provided by the present invention is as follows: The variable-diameter supported pipeline robot based on Mecanum wheels includes an overall frame module, a variable-diameter support module, and a drive module. The variable-diameter supported pipeline robot based on Mecanum wheels realizes operations inside the pipeline, including the following steps (as Figure 10 shown): 1. The pipeline robot enters the working environment - the pipeline. The motor of the electric push rod 111 of the variable-diameter support module 100 rotates to drive the electric push rod to extend. Since both ends of the electric push rod 111 are respectively fixed to the push rod support plate 302 and the driving swing rod 102, the thrust generated by the extension of the electric push rod 111 provides torque for the driving swing rod 102 to rotate around the swing rod shaft 108. Due to the parallel double swing rod structure, while the parallel driving swing rod 102 and the supporting swing rod 103 rotate around the swing rod shaft 108 respectively, the front fork 104 always rotates around the front fork shaft 105 while maintaining a parallel attitude with the inner wall of the pipeline.

[0025] 2. The driving module 200 installed on the front fork 104 is affected by the rotational torque of the driving swing rod 102, and the Mecanum wheels of the driving module 200 generate supporting force and frictional force with the inner wall of the pipeline.

[0026] 3. The 6 variable-diameter support modules installed on the fuselage are all deployed according to the above steps 1 and 2.

[0027] 4. When the supporting force and frictional force generated between the Mecanum wheels and the pipe wall are sufficient, the motor of the electric push rod 111 stops rotating and locks. At this time, the driving coded motor 205 of the driving module 200 starts and drives the Mecanum wheels to rotate through the coupling.

[0028] 5. Since the characteristics of the omnidirectional movement of the Mecanum wheels are utilized during the operation of the present invention, the driving module 200 of the front support structure is installed with left-handed Mecanum wheels 201, and the driving module 200 of the rear support structure is installed with right-handed Mecanum wheels 202. Therefore, by controlling the rotation speed and direction of the Mecanum wheels, the pipeline robot can achieve flexible attitude transformation inside the pipeline.

[0029] 6. When the present invention moves translationally forward along the pipeline, the Mecanum wheels of the driving modules installed on the front forks of the 3 variable-diameter support modules included in the front support structure rotate in the forward direction; the Mecanum wheels of the driving modules installed on the front forks of the 3 variable-diameter support modules included in the rear support structure rotate in the reverse direction (as Figure 8 ).

[0030] 7. When the present invention rotates clockwise along the pipeline axis, the Mecanum wheels of the driving modules installed on the front forks of the 3 variable-diameter support modules included in the front support structure rotate in the forward direction; the Mecanum wheels of the driving modules installed on the front forks of the 3 variable-diameter support modules included in the rear support structure rotate in the forward direction (as Figure 9 ).

[0031] 8. When the present invention rotates counterclockwise along the pipeline axis, the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the front support structure turn in the reverse direction; the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the rear support structure turn in the reverse direction (as Figure 10 ).

[0032] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A variable-diameter support type pipeline robot based on Mecanum wheels, characterized in that, It includes a variable-diameter support module (100), a driving module (200), and an overall frame module (300). A number of groups of variable-diameter support modules (100) are evenly distributed in the circumferential direction of the overall frame module (300). A number of groups of variable-diameter support modules (100) evenly distributed in the circumferential direction form a set of support structures, and at least two sets of support structures are provided in the length direction of the overall frame module (300). Each group of variable-diameter support modules (100) includes at least a swing rod and an electric push rod for driving the swing rod to swing, and the driving module (200) is installed at the free end of the swing rod. The driving module (200) is a Mecanum wheel driven by a motor. The rotation directions of the Mecanum wheels on the same set of support structures are the same, and the rotation directions of the Mecanum wheels on different sets of support structures are different.

2. The variable-diameter supported pipeline robot based on Mecanum wheels according to claim 1, wherein The overall frame module (300) is composed of 1 head plate (301), 4 push rod support plates (302), 1 middle plate (303), 3 support positioning plates (304), and 1 tail plate (305); the 3 support positioning plates (304) are circumferentially distributed, spaced 120° from each other; the head plate (301), the push rod support plates (302), the middle plate (303), and the tail plate (305) are sequentially fixed to the positioning holes of the support positioning plates (304), and the head plate (301), the push rod support plates (302), the middle plate (303), and the tail plate (305) are connected to the support positioning plates (304) by M8 screws (306).

3. The variable-diameter supported pipeline robot based on Mecanum wheels according to claim 1 or 2, characterized in that Three variable-diameter support modules (100) are installed at intervals of 120° radially between the push rod support plate (302) and the middle plate (303) to form a set of support structures, namely the front support structure; three variable-diameter support modules (100) are installed at intervals of 120° radially between the push rod support plate (302) and the tail plate (305) to form a set of support structures, namely the rear support structure; the push rod support plate (302) and the middle plate (303) are components of the overall frame module (300) and are fixedly connected to the support positioning plate (304).

4. The variable-diameter support type pipeline robot based on Mecanum wheels according to claim 3, wherein, The variable-diameter support module (100) includes one swing rod connecting piece (101), one driving swing rod (102), one supporting swing rod (103), one front fork (104), four front fork shafts (105), eight D10 flange bearings (106), six D15 flange bearings (107), two swing rod shafts (108), one push rod shaft (109), one push rod connecting piece (110), one electric push rod (111) and one push rod mounting seat (112); the push rod mounting seat (112) is connected to the push rod support plate (302) by screws, the swing rod connecting piece (101) is connected to the middle plate (303) by screws, and the front end of the push rod support plate (302) and the electric push rod (111) are connected through the push rod mounting seat (112); the front end of the driving swing rod (102) and the swing rod connecting piece (101) are connected by a swing rod shaft (108); the front end of the supporting swing rod (103) and the swing rod connecting piece (101) are connected by a swing rod shaft (108), and the swing rod shaft (108) is installed on the swing rod connecting piece (101) through a D15 flange bearing (107); the rear end of the driving swing rod (102) and the front fork (104) are connected by a front fork shaft (105), the rear end of the supporting swing rod (103) and the front fork (104) are connected by a front fork shaft (105), and the driving swing rod (102) and the supporting swing rod (103) form a parallel double swing rod structure; the front fork shaft (105) is installed on the front fork (104) through a D10 flange bearing (106), the front end of the electric push rod (111) is installed on the push rod mounting seat (112), the rear end of the electric push rod (111) is connected to the driving swing rod (102) through a push rod shaft (109), and the push rod shaft (109) is connected to the driving swing rod (102) through a D15 flange bearing (107).

5. The variable-diameter supported pipeline robot based on Mecanum wheels according to claim 1 or 2, characterized in that, The driving module (200) includes one left-handed Mecanum wheel (201) or one right-handed Mecanum wheel (202), a Mecanum wheel flange one (203), one Mecanum wheel flange two (204), one driving coded motor (205) and one motor support frame (206); the Mecanum wheel flange one (203) and the Mecanum wheel flange two (204) are respectively fixed on both sides of the left-handed Mecanum wheel (201) by bolts and nuts, the Mecanum wheel flange two (204) is provided with a coupling and is connected to the rotating shaft of the driving coded motor (205) through this coupling, the driving coded motor (205) is fixed on the motor support frame (206) by screws, and the motor support frame (206) is fixed on the front fork (104) by bolts and nuts.

6. The variable-diameter supported pipeline robot based on Mecanum wheels according to claim 3, wherein: The front support structure and the rear support structure provide support for the main body of the variable-diameter supported pipeline robot based on Mecanum wheels. The front support structure includes: 3 variable-diameter support modules (100) and 3 Mecanum wheel drive modules (200) with left-handed Mecanum wheels (201); the Mecanum wheel drive modules (200) with left-handed Mecanum wheels (201) are respectively installed on the front forks (104) at the ends of the variable-diameter support modules (100), and are installed on the middle plate (303) at intervals of 120° from each other; the rear support structure includes: 3 variable-diameter support modules (100) and 3 Mecanum wheel drive modules (200) with right-handed Mecanum wheels (202); the Mecanum wheel drive modules (200) with right-handed Mecanum wheels (202) are respectively installed on the front forks (104) at the ends of the variable-diameter support modules (100), and are installed on the tail plate (305) at intervals of 120° from each other.

7. A working method of the variable-diameter supported pipeline robot based on Mecanum wheels according to any one of claims 1-5, characterized in that: (1) The pipeline robot enters the pipeline working environment. The motor of the electric push rod (111) of the variable-diameter support module (100) rotates to drive the electric push rod to extend. Since the two ends of the electric push rod (111) are respectively fixed to the push rod support plate (302) and the driving swing rod (102), the thrust generated by the extension of the electric push rod (111) provides torque for the driving swing rod (102) to rotate around the swing rod axis (108). Due to the parallel double swing rod structure, while the parallel driving swing rod (102) and the supporting swing rod (103) rotate around the swing rod axis (108) respectively, the front fork (104) always maintains a parallel posture with the inner wall of the pipeline and rotates around the front fork axis (105). (2) The drive module (200) installed on the front fork (104) is affected by the rotational torque of the driving swing rod (102), and the Mecanum wheel of the drive module (200) generates a supporting force and a frictional force with the inner wall of the pipeline. (3) The 6 variable-diameter support modules installed on the fuselage are all deployed according to the above steps (1) and (2). (4) When the supporting force and the frictional force generated between the Mecanum wheel and the pipe wall are sufficient, the motor of the electric push rod (111) stops rotating and self-locks. At this time, the drive coding motor (205) of the drive module (200) starts, and drives the Mecanum wheel to rotate through the coupling. (5) Since the drive module (200) of the front support structure is installed with a left-handed Mecanum wheel (201), and the drive module (200) of the rear support structure is installed with a right-handed Mecanum wheel (202), by controlling the rotation speed and steering of the left-handed Mecanum wheel (201) and the right-handed Mecanum wheel (202), the pipeline robot can realize flexible posture transformation in the pipeline.

8. A working method of the variable-diameter supported pipeline robot based on Mecanum wheels according to claim 6, characterized in that: (1) When moving forward translationally along the pipeline, the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the front support structure rotate forward; the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the rear support structure rotate backward. (2) When rotating clockwise along the pipeline axis, the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the front support structure rotate forward; the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the rear support structure rotate forward. (3) When rotating counterclockwise along the pipeline axis, the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the front support structure rotate backward; the Mecanum wheels of the drive modules installed on the front forks of the three variable-diameter support modules included in the rear support structure rotate backward.

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