Variable-diameter robot for pipeline inspection and control method thereof

Abstract

The application belongs to the technical field of variable-diameter robots, and discloses a variable-diameter robot for pipeline detection and a control method thereof. The robot comprises mounting plates and a sliding seat. A plurality of first guide light axes are arranged in the circumferential direction in adjacent two mounting plates. A positive and negative tooth ball screw is arranged in the axial direction in the adjacent two mounting plates. The lower end of the mounting plate is provided with a fixedly connected fixing plate. The two sides of the sliding seat are provided with guide sliding blocks. The side, away from the first guide light axis, of the guide sliding block is provided with an adjusting unit. The adjusting unit is rotationally connected with the guide sliding block through a connecting piece for variable-diameter adjustment. A sensor is arranged on the fixing plate for acquiring the acceleration of the robot in the pipeline, improving the consistency and coaxiality of the variable-diameter process of the robot. The fixing plate at the lower end of the mounting plate is provided with a sensor for acquiring the acceleration of the robot in the pipeline in real time, improving the stability of the robot walking in the pipeline and the accuracy of the detection data.

Description

Technical Field

[0001] This invention belongs to the field of variable diameter robot technology, and relates to a variable diameter robot for pipeline inspection and its control method. Background Technology

[0002] To achieve pipe diameter changes, existing robots often employ a structure of multiple independently driven rotating arms. While this can adapt to changes in pipe diameter, the lack of synchronization between the rotating arms makes it difficult to guarantee coaxiality. When the robot moves inside the pipe, it is prone to off-center loading, which in turn causes irregular fluctuations in the distance collected by the detection sensors, affecting the accuracy and stability of the detection data.

[0003] Most existing robots use a four-wheel or two-wheel structure. When walking inside a vertical tube, due to insufficient gravity and adhesion to the tube wall, they have poor support stability, are prone to slipping, and are difficult to provide continuous driving force. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a variable diameter robot for pipeline inspection and its control method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a variable-diameter robot for pipeline inspection, comprising a mounting plate and a slide. Several first guide optical axes are arranged circumferentially within two adjacent mounting plates, and positive and negative toothed ball screws are arranged axially within two adjacent mounting plates. A fixed plate is fixedly connected to the lower end of each mounting plate. Guide sliders are arranged on both sides of the slide. An adjustment unit is arranged on the side of each guide slider away from the first guide optical axes. The adjustment unit is rotatably connected to the guide slider via a connector for variable-diameter adjustment. A sensor is arranged on the fixed plate to acquire the robot's acceleration within the pipeline.

[0006] Furthermore, the adjustment unit includes a first connecting rod, a second connecting rod, a third connecting rod, a second guide optical axis, and a positioning slider. The guide slider includes a first guide slider and a second guide slider. The first connecting rod is disposed on both sides of the mounting plate. One end of the first connecting rod is rotatably connected to the mounting plate, and the other end is rotatably connected to the positioning slider. One end of the second connecting rod is rotatably connected to the first guide slider, and the other end is rotatably connected to the positioning slider. One end of the third connecting rod is rotatably connected to the second guide slider, and the other end is rotatably connected to the first connecting rod. The positioning slider is sleeved on the outer surface of the second guide optical axis.

[0007] Furthermore, the slide is sleeved on the outer surface of the forward and reverse toothed ball screw, the lug of the slide is sleeved on the outer surface of the first guide optical axis, the guide slider is disposed on both sides of the lug of the slide, the slide is provided with a first fastener slidably connected to the first guide optical axis on the side away from the mounting plate, and a second fastener slidably connected to the first guide optical axis on the other side.

[0008] Furthermore, the adjustment unit also includes a support frame fixedly connected to both ends of the second guide optical axis. One end of the support frame near the positive and negative tooth ball screw is provided with a traveling bracket, and the other end is provided with a roller. The support frame is fixedly connected to the traveling bracket and rotatably connected to the roller.

[0009] Furthermore, the adjustment unit also includes a steering unit and a connecting shaft. The steering unit passes through the connecting shaft and is installed between the support frame and the roller. The input end of the steering unit is used to connect with the drive component.

[0010] Furthermore, the positioning slider includes a first positioning slider and a second positioning slider, with the other end of the first connecting rod rotatably connected to the first positioning slider and the other end of the second connecting rod rotatably connected to the second positioning slider.

[0011] Furthermore, a limiting ring is fixedly connected between both ends of the first guide optical shaft and the mounting plate; a driving component is provided at one end of the positive and negative tooth ball screw, and the output end of the driving component is connected to the positive and negative tooth ball screw through a coupling; a limiting ring is fixedly connected between the second guide optical shaft and the traveling bracket, and an elastic component is also provided between the limiting ring and the second guide optical shaft, and the elastic component is sleeved on the outer surface of the second guide optical shaft.

[0012] This invention also provides a control method for a variable-diameter robot used for pipeline inspection. Based on the aforementioned variable-diameter robot for pipeline inspection, the method includes the following steps: determining whether the robot's posture has deviated; if so, acquiring the lateral and vertical gravity components from the accelerometer in the sensor; calculating the static roll angle based on the lateral and vertical gravity components, fusing the static roll angle with the angular velocity of the gyroscope to obtain the real-time roll angle of the fixed plate; determining whether the real-time roll angle of the fixed plate deviates from 0°; if so, multiplying the real-time roll angle of the adjustment unit by the posture proportional coefficient to calculate the dynamic speed compensation amount; and performing homing control on the variable-diameter robot based on the dynamic speed compensation amount.

[0013] Furthermore, the adjustment unit includes a first adjustment unit, a second adjustment unit, and a third adjustment unit. The first adjustment unit is disposed at the upper end of the mounting plate, and the second and third adjustment units are symmetrically disposed on both sides of the mounting plate. The adjustment unit is calibrated based on the dynamic speed compensation amount, including: superimposing the dynamic speed compensation amount into the second and third adjustment units in the form of a positive and a negative differential speed.

[0014] Furthermore, the static roll angle is :

[0015] in, This represents the lateral component of gravity. This represents the vertical component of gravity. The real-time roll angle is :

[0016] in, The weighting coefficients are the filtering time constants. The roll angle of the fixed plate in the previous sampling period. Let be the angular velocity of the gyroscope. The sampling period is This is the static roll angle; The dynamic speed compensation amount is :

[0017] in, This is the attitude scaling factor. This is the real-time roll angle.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a variable-diameter robot for pipeline inspection. A guide optical axis is circumferentially positioned between adjacent mounting plates, and forward and reverse toothed ball screws are axially positioned. The forward and reverse toothed ball screws provide linear guidance to a first and second fastener, which in turn provide linear guidance to a slide block and a guide slider. Guide sliders are located on both sides of the slide block, synchronously driving the extension and retraction of an adjustment unit to improve the consistency and coaxiality of the diameter-changing process. A sensor is installed on a fixed plate at the lower end of the mounting plates to acquire the robot's acceleration within the pipeline in real time, improving the robot's stability during pipeline movement and the accuracy of the inspection data.

[0019] The first, second, and third connecting rods are symmetrically arranged on both sides of the mounting plate and the guide slider, and are forced to move synchronously during the diameter change process, which improves the synchronization and coaxiality of the diameter change and avoids the problem of uneven load. The first, second, and third connecting rods cooperate with the guide optical axis and the positioning slider to enhance the support stability and anti-slippage in the vertical tube.

[0020] This invention discloses a control method for a variable-diameter robot used for pipeline inspection. The static roll angle is calculated based on the lateral and vertical gravity components from the accelerometer and fused with the angular velocity from the gyroscope to obtain the real-time roll angle of the fixed plate, suppressing drift errors from a single sensor. When the real-time roll angle deviates from 0°, it is multiplied by the attitude proportionality coefficient to obtain a dynamic velocity compensation amount, enabling closed-loop control of the variable-diameter robot. This real-time correction of the robot's rolling posture within the pipeline improves the accuracy of pipeline inspection data and the stability of long-term operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a variable diameter robot for pipeline inspection according to the present invention; Figure 2 This is a schematic diagram of the structure of the adjustment unit in an embodiment of the present invention; Figure 3 This is a schematic diagram of the guide slider in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the adjustment unit in an embodiment of the present invention; Figure 5 This is a front view of the adjustment unit in an embodiment of the present invention; Figure 6 This is a flowchart of a control method for a variable-diameter robot used for pipeline inspection according to the present invention.

[0022] Figure label: 1-Mounting plate; 2-First guide optical axis; 3-Forward and reverse toothed ball screw; 4-Slide block; 5-Guide slider; 51-First guide slider; 52-Second guide slider; 6-Adjustment unit; 61-First connecting rod; 62-Second connecting rod; 63-Third connecting rod; 64-Second guide optical axis; 65-Positioning slider; 651-First positioning slider; 652-Second positioning slider; 66-Support frame; 67-Traveling bracket; 68-Roller; 69-Steering unit; 7-First fastener; 8-Second fastener; 9-Limit ring. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] Example 1 This invention discloses a variable-diameter robot for pipeline inspection, comprising a mounting plate 1 and a slide 4. A plurality of first guide optical axes 2 are arranged circumferentially within two adjacent mounting plates 1, and positive and negative toothed ball screws 3 are arranged axially within two adjacent mounting plates 1. A fixed plate is fixedly connected to the lower end of each mounting plate 1. Guide sliders 5 are arranged on both sides of the slide 4. An adjustment unit 6 is arranged on the side of each guide slider 5 away from the first guide optical axes 2. The adjustment unit 6 is rotatably connected to the guide slider 5 via a connector for variable-diameter adjustment. A sensor is arranged on the fixed plate to acquire the robot's acceleration within the pipeline.

[0025] Mounting plate 1 includes a first mounting plate and a second mounting plate, such as Figure 1 As shown, the left side of the forward and reverse toothed ball screw 3 is the first mounting plate, and the right side is the second mounting plate. A first guide shaft 2 and the forward and reverse toothed ball screw 3 are arranged between the first and second mounting plates. In this embodiment, there are three first guide shafts 2, arranged at 120° circumferentially, ensuring that the mounting plate 1, guide slider 5, and adjustment unit 6 are subjected to balanced forces in the circumferential direction. This avoids the problems of uneven loading and jamming caused by insufficient number or uneven distribution of the first guide shafts 2, improving the smoothness and coaxiality of the motion during the diameter change process. Simultaneously, the three-point support structure can constrain the radial and circumferential degrees of freedom of each component, enhancing the robot's anti-torsion ability when walking inside a vertical tube and reducing posture deviation caused by uneven reaction forces from the tube wall.

[0026] The forward and reverse toothed ball screw 3 is arranged axially, and the axis of the forward and reverse toothed ball screw 3 is parallel to the axis of the first guide optical axis 2. The mounting plate 1 is an equilateral triangular 6061 aluminum alloy plate structure, which is lightweight and has high strength. It has a mounting hole in the center for mounting the camera. The first guide optical axis 2 is a chrome-plated optical axis with high surface hardness and good wear resistance, providing guidance and sliding for the guide slider 5.

[0027] A slide 4 is fitted on the outer surface of the forward and reverse thread ball screw 3. The ear seat of the slide 4 is fitted on the outer surface of the first guide shaft 2. The slide 4 and the ear seat are an integral structure. A first fastener 7 is provided between the two slides 4. A second fastener 8 is provided at the end of the slide 4 near the mounting plate 1. The first fastener 7 and the second fastener 8 near the first mounting plate are installed on the forward thread section of the forward and reverse thread ball screw 3. The first fastener 7 and the second fastener 8 near the second mounting plate are installed on the reverse thread section of the forward and reverse thread ball screw 3.

[0028] In this embodiment, the first fastener 7 is a first lead screw nut, and the second fastener 8 is a second lead screw nut. The first fastener 7 and the second fastener 8 are installed on both sides of the slide block 4.

[0029] like Figure 1 As shown, a drive unit is provided at the right end of the forward and reverse toothed ball screw 3. The output end of the drive unit is connected to the forward and reverse toothed ball screw 3 via a coupling to drive the forward and reverse toothed ball screw 3 to rotate. Guide sliders 5 are provided on both sides of the lug of the slide 4. The guide sliders 5 include a first guide slider 51 and a second guide slider 52, as shown. Figure 3 As shown, the second guide slider 52 is located on the side closest to the mounting plate 1, and the first guide slider 51 is disposed between the two second guide sliders 52. When the forward and reverse tooth ball screw 3 rotates, it drives the two slide blocks 4 to move in opposite or opposite linear motions along the axis of the forward and reverse tooth ball screw 3.

[0030] Guide slider 5 and mounting plate 1 are rotatably connected to adjustment unit 6 via connectors. Adjustment unit 6 includes first connecting rod 61, second connecting rod 62, third connecting rod 63, second guide optical shaft 64, and positioning slider 65. Positioning slider 65 is sleeved on the outer surface of second guide optical shaft 64. Figure 2 As shown, the positioning slider 65 includes a first positioning slider 651 and a second positioning slider 652. The second positioning slider 652 is disposed at both ends near the second guide optical axis 64. One end of the first connecting rod 61 is rotatably connected to the mounting plate 1, and the other end is rotatably connected to the first positioning slider 651. One end of the second connecting rod 62 is rotatably connected to the first guide slider 51, and the other end is rotatably connected to the second positioning slider 652. One end of the third connecting rod 63 is rotatably connected to the second guide slider 52, and the other end is rotatably connected to the first connecting rod 61. It should be noted that the first connecting rod 61, the second connecting rod 62, and the third connecting rod 63 are symmetrically installed on both sides of the mounting plate 1 and the guide slider 5.

[0031] The adjustment unit 6 also includes a support frame 66 fixedly connected to both ends of the second guide optical axis 64. The support frame 66 has a traveling bracket 67 at one end near the positive and negative tooth ball screw 3 and a roller 68 at the other end. The support frame 66 is fixedly connected to the traveling bracket 67 and rotatably connected to the roller 68.

[0032] Specifically, the adjustment unit 6 also includes a support frame 66 fixedly connected to both ends of the second guide optical axis 64, such as... Figure 5 As shown, the lower end of the support frame 66 is provided with a roller 68, and the upper end is provided with a traveling bracket 67. The support frame 66 and the traveling bracket 67 are fixedly connected by a connector, and the connecting shaft passes through the roller 68 and is fixed to both ends of the support frame 66. Figure 4 As shown, a limiting ring 9 is fixedly connected between the second guide optical axis 64 and the traveling bracket 67 to limit the extreme sliding stroke of the guide slider 5 and the positioning slider 65, and to prevent overtravel and absorption of inner wall impact. An elastic element is also provided between the limiting ring 9 and the second guide optical axis 64. The elastic element is sleeved on the outer surface of the second guide optical axis 64. The elastic element can provide preload and buffering effect during the diameter change process, eliminate the impact and vibration caused by machining errors or movement gaps, thereby improving the movement stability and diameter change synchronization accuracy of the adjustment unit 6.

[0033] The adjustment unit 6 also includes a steering unit 69 and a connecting shaft. The steering unit 69 passes through the connecting shaft and is installed between the support frame 66 and the roller 68. The input end of the steering unit 69 is used to connect with the drive component.

[0034] The adjustment unit 6 also includes a steering unit 69 and a connecting shaft. The steering unit includes an active bevel gear and a driven bevel gear. The active bevel gear is fixed on the output shaft of the drive component, which is a motor. The active and driven bevel gears mesh to form a 90° right-angle transmission pair, realizing right-angle reversal of power. Three rollers 68 are controlled by three motors respectively, enabling the robot to achieve differential motion. The surface of the rollers 68 is provided with an anti-slip knurled texture. In this embodiment, there are three sets of adjustment units. The three-point support structure can ensure the stability of the robot's movement and prevent slippage. A controller is also provided on the fixed plate, which is electrically connected to the sensor. The sensor is used for laser ranging.

[0035] The working principle of a variable diameter robot for pipeline inspection according to the present invention: The drive unit provides power, and the output end drives the positive and negative thread ball screws 3 to rotate via a coupling. The positive thread section and the negative thread section on the positive and negative thread ball screws 3 rotate synchronously, driving the two slides 4 to move in opposite or opposite linear motions along the axis of the positive and negative thread ball screws 3. When the slides 4 move, they drive the guide sliders 5 on both sides to move synchronously. The guide sliders 5 are rotatably connected to the first link 61, the second link 62, and the third link 63 in the adjustment unit 6 through connecting parts, converting the linear motion of the slides 4 into the sliding motion of the positioning sliders 65. The first positioning slider 651 and the second positioning slider 652 slide along the second guide optical axis 64, driving the support frame 66 and the roller 68 to perform radial extension and retraction, thereby adapting to pipes with different inner diameters. The steering unit 69 forms a 90° right-angle transmission pair through the meshing of the active bevel gear and the driven bevel gear to achieve differential motion. Sensors mounted on the fixed plate acquire the robot's acceleration signal in the pipe in real time, and the camera in the mounting hole in the center of the mounting plate 1 detects the inside of the pipe.

[0036] Example 2 This invention discloses a method for using a variable-diameter robot for pipeline inspection: like Figure 6 As shown, the inner diameter parameters of the target pipe are first obtained. Based on the inner diameter parameters, the drive component connected to the forward and reverse thread ball screw 3 is controlled. The drive component drives the forward and reverse thread ball screw 3 to rotate through the coupling. The forward and reverse thread ball screw 3 provides linear guidance to the first fastener 7 and the second fastener 8. The first fastener 7 and the second fastener 8 provide linear guidance to the slide 4, so that the two slides 4 move towards or away from each other along the axial direction. The slide 4 drives the guide slider 5 to move. The positioning slider 65 is driven to slide along the second guide optical axis 64 through the first link 61, the second link 62 and the third link 63 in the adjustment unit 6. The radial extension size of the support frame 66 and the roller 68 is adjusted. The roller 68 is controlled by an independent motor. The robot moves forward, backward and turns in the pipe through differential motion control. The camera at the center mounting hole of the mounting plate 1 collects the image data inside the pipe in real time. The sensor on the fixed plate collects the robot's running acceleration information synchronously.

[0037] The variable-diameter robot then begins automatic inspection. If the robot's posture deviates, the lateral gravity component from the accelerometer in the sensor is first acquired. and vertical gravitational component The static roll angle is calculated using inverse trigonometric functions. The static roll angle is: .

[0038]

[0039] in, This represents the lateral component of gravity. This represents the vertical component of gravity.

[0040] Then, the angular velocity of the gyroscope is read in real time. The angular velocity of the gyroscope With static roll angle Perform fusion and calculate real-time roll angle .

[0041]

[0042] in, The weighting coefficients are the filtering time constants. The roll angle of the fixed plate in the previous sampling period. Let be the angular velocity of the gyroscope. The sampling period is This is the static roll angle.

[0043] Determine whether the real-time roll angle of the fixed plate deviates from 0°. If it deviates from 0°, multiply the real-time roll angle of the adjustment unit 6 by the attitude proportional coefficient to calculate the dynamic speed compensation amount.

[0044] Dynamic speed compensation amount is :

[0045] in, This is the attitude scaling factor. This is the real-time roll angle.

[0046] The adjustment unit 6 is used for alignment control based on dynamic speed compensation. The adjustment unit 6 includes a first adjustment unit, a second adjustment unit, and a third adjustment unit. The first adjustment unit is located at the upper end of the mounting plate 1, while the second and third adjustment units are symmetrically arranged on both sides of the mounting plate 1. The cruising speed of the first adjustment unit is set to... The dynamic speed compensation is superimposed on the second and third adjustment units in the form of a positive and negative differential speed. The speed of the second adjustment unit is... + The speed of the third adjustment unit is - The asymmetric speed difference directly generates a reverse driving torque on the tube wall, forcing the robot to adaptively reverse until the roll angle converges back to positive.

[0047] Each adjustment unit 6 is also equipped with a sensor at its front end to determine whether the variable diameter robot needs obstacle avoidance control. During obstacle avoidance control, when any set of sensors detects that the distance to the front is less than a preset value, two sets of control adjustment units 6 are kept rotating forward, while the other set reduces its rotation speed. The generated asymmetric driving torque enables the variable diameter robot to generate controllable spin and yaw attitude to overcome obstacles along the central axis inside the pipe. Then, the roller 68 is used to restore the attitude and resume three-axis synchronous propulsion. The camera collects the flat image inside the pipe in real time and inputs it into the convolutional neural network model. Through feature extraction of multi-level convolutional layers and pooling layers, the type and coordinates of cracks and corrosion are output.

[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

Claims

1. A variable-diameter robot for pipeline inspection, characterized in that: The system includes a mounting plate (1) and a slide (4). Several first guide optical axes (2) are arranged circumferentially inside two adjacent mounting plates (1). A positive and negative tooth ball screw (3) is arranged axially inside two adjacent mounting plates (1). A fixed plate is fixedly connected to the lower end of the mounting plate (1). Guide sliders (5) are arranged on both sides of the slide (4). An adjustment unit (6) is arranged on the side of the guide slider (5) away from the first guide optical axis (2). The adjustment unit (6) is rotatably connected to the guide slider (5) through a connector for diameter adjustment. A sensor is arranged on the fixed plate for obtaining the acceleration of the robot in the pipe.

2. The variable diameter robot for pipeline inspection according to claim 1, characterized in that: The adjustment unit (6) includes a first connecting rod (61), a second connecting rod (62), a third connecting rod (63), a second guide optical axis (64), and a positioning slider (65). The guide slider (5) includes a first guide slider (51) and a second guide slider (52). The first connecting rod (61) is disposed on both sides of the mounting plate (1). One end of the first connecting rod (61) is rotatably connected to the mounting plate (1), and the other end is rotatably connected to the positioning slider (65). One end of the second connecting rod (62) is rotatably connected to the first guide slider (51), and the other end is rotatably connected to the positioning slider (65). One end of the third connecting rod (63) is rotatably connected to the second guide slider (52), and the other end is rotatably connected to the first connecting rod (61). The positioning slider (65) is sleeved on the outer surface of the second guide optical axis (64).

3. The variable diameter robot for pipeline inspection according to claim 1, characterized in that: The slide (4) is sleeved on the outer surface of the forward and reverse toothed ball screw (3). The lug of the slide (4) is sleeved on the outer surface of the first guide optical shaft (2). The guide slider (5) is arranged on both sides of the lug of the slide (4). The slide (4) is provided with a first fastener (7) that is slidably connected to the first guide optical shaft (2) on one side away from the mounting plate (1), and a second fastener (8) that is slidably connected to the first guide optical shaft (2) on the other side.

4. The variable diameter robot for pipeline inspection according to claim 2, characterized in that: The adjustment unit (6) also includes a support frame (66) fixedly connected to both ends of the second guide optical axis (64). The support frame (66) has a walking bracket (67) at one end near the positive and negative tooth ball screw (3) and a roller (68) at the other end. The support frame (66) is fixedly connected to the walking bracket (67) and rotatably connected to the roller (68).

5. The variable diameter robot for pipeline inspection according to claim 4, characterized in that: The adjustment unit (6) also includes a steering unit (69) and a connecting shaft. The steering unit (69) passes through the connecting shaft and is installed between the support frame (66) and the roller (68). The input end of the steering unit (69) is used to connect with the drive component.

6. The variable diameter robot for pipeline inspection according to claim 2, characterized in that: The positioning slider (65) includes a first positioning slider (651) and a second positioning slider (652). The other end of the first connecting rod (61) is rotatably connected to the first positioning slider (651), and the other end of the second connecting rod (62) is rotatably connected to the second positioning slider (652).

7. The variable-diameter robot for pipeline inspection according to claim 4, characterized in that: A limiting ring (9) is fixedly connected between the two ends of the first guide optical shaft (2) and the mounting plate (1); a driving component is provided at one end of the positive and negative tooth ball screw (3), and the output end of the driving component is connected to the positive and negative tooth ball screw (3) through a coupling; A limiting ring (9) is fixedly connected between the second guide optical axis (64) and the walking bracket (67). An elastic element is also provided between the limiting ring (9) and the second guide optical axis (64), and the elastic element is sleeved on the outer surface of the second guide optical axis (64).

8. A control method for a variable-diameter robot used for pipeline inspection, characterized in that, The variable-diameter robot for pipeline inspection according to any one of claims 1-7 includes the following steps: Determine whether the orientation of the variable-diameter robot has shifted; If a shift occurs, acquire the lateral and vertical gravity components from the accelerometer in the sensor; The static roll angle is calculated based on the horizontal and vertical gravity components, and then fused with the angular velocity of the gyroscope to obtain the real-time roll angle of the fixed plate. Determine whether the real-time roll angle of the fixed plate deviates from 0°. If it deviates from 0°, multiply the real-time roll angle of the adjustment unit (6) by the attitude proportional coefficient and calculate the dynamic speed compensation amount. The variable-diameter robot is rectified based on dynamic speed compensation.

9. The control method for a variable-diameter robot for pipeline inspection according to claim 8, characterized in that: The adjustment unit (6) includes a first adjustment unit, a second adjustment unit and a third adjustment unit. The first adjustment unit is disposed at the upper end of the mounting plate (1), and the second adjustment unit and the third adjustment unit are disposed on both sides of the mounting plate (1) in a symmetrical structure. Adjusting the speed of the adjustment unit (6) based on the dynamic speed compensation amount includes: The dynamic speed compensation is superimposed on the second and third adjustment units in the form of a positive and a negative differential.

10. The control method for a variable-diameter robot for pipeline inspection according to claim 8, characterized in that: The static roll angle is : in, This represents the lateral component of gravity. This represents the vertical component of gravity. The real-time roll angle is : in, The weighting coefficients are the filtering time constants. The roll angle of the fixed plate in the previous sampling period. Let be the angular velocity of the gyroscope. The sampling period is This is the static roll angle; The dynamic speed compensation amount is : in, This is the attitude scaling factor. This is the real-time roll angle.

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