Pipeline inspection robot and method based on precession and creep dual drive of Stewart mechanism

Abstract

The application relates to a helical and peristaltic double driving pipeline detection robot and method based on a Stewart mechanism, which comprises a rotating assembly, a moving platform, a Stewart mechanism, a static platform and an ultrasonic flaw detection assembly, the rotating assembly is connected with the first end of the moving platform, the second end of the moving platform is connected with the first end of the Stewart mechanism, the second end of the Stewart mechanism is connected with the static platform respectively, the Stewart mechanism can select a forward direction at a pipeline tee joint, can adapt to a turning radius in a curved pipeline, can change a driving mode according to actual conditions in the pipeline by simultaneously cooperating with a variable-angle structure and a variable-diameter structure, can autonomously avoid obstacles, and can adapt to different inner diameters of the pipeline.

Description

Technical Field

[0001] The present invention relates to the field of robots, and in particular to a pipeline detection robot and method based on a Stewart mechanism with dual drive of precession and peristalsis. Background Art

[0002] Pipeline transportation is an economical, efficient and safe mode of transportation, and is often used to transport fluid media. However, during the use of pipelines, due to the influence of the transportation medium or the external environment, defects such as corrosion, rupture, disconnection, and misalignment may occur inside the pipeline. In order to reduce inspection costs and improve the working conditions of inspectors, designers have designed an in-pipeline robot for pipeline transportation.

[0003] However, existing in-pipe robots cannot choose the direction of travel at the tee, cannot adapt to the turning radius of the curved pipe, have a single driving mode, have poor obstacle avoidance ability in the pipe, have low flexibility, and cannot adapt to a variety of pipe inner diameters. Therefore, there is an urgent need to study a new robot structure that can solve the defects of the existing technology. Summary of the Invention

[0004] In order to solve the problems mentioned in the above background technology that the existing in-pipeline robots are unable to select the forward direction at the tee, cannot adapt to the turning radius of the curved pipe, have a single driving mode, have poor obstacle avoidance ability in the pipeline, have low flexibility and cannot adapt to a variety of pipeline inner diameters, the present invention provides a pipeline inspection robot and method with dual drive of precession and peristalsis based on a Stewart mechanism. The in-pipeline robot can not only select the forward direction at the tee, adapt to the turning radius of the curved pipe, and avoid obstacles, but also has two driving modes of precession and peristalsis, so that the in-pipeline robot involved in the present invention is more flexible than the existing in-pipeline robots.

[0005] Specifically, the present invention provides a dual-drive pipeline inspection robot based on a Stewart mechanism, which includes a rotating assembly, a moving platform, a Stewart mechanism, a static platform, and an ultrasonic flaw detection assembly. The rotating assembly is connected to a first end of the moving platform, a second end of the moving platform is connected to a first end of the Stewart mechanism, and the second ends of the Stewart mechanisms are respectively connected to the static platforms.

[0006] The rotating assembly includes a first angle-changing structure, a diameter-changing structure, a rotating assembly output shaft, and an anti-blocking base. The first angle-changing structure and the diameter-changing structure are evenly arranged in multiple groups on the periphery of the anti-blocking base. The first end of the diameter-changing structure is connected to the anti-blocking base, and the second end of the diameter-changing structure is connected to the first angle-changing structure. The rotating assembly output shaft is arranged on the anti-blocking base.

[0007] The moving platform includes an AC reduction motor, a rotating assembly output shaft, a coupling, an AC reduction motor bracket, a Hooke's hinge mounting plate, and a moving platform base. The moving platform base is connected to the anti-blocking base. The AC reduction motor is mounted on the AC reduction motor bracket. The AC reduction motor bracket and the Hooke's hinge mounting plate are both mounted on the moving platform base. The output shaft of the AC reduction motor is connected to the output shaft of the rotating assembly through a coupling.

[0008] The Stewart mechanism includes multiple groups of Stewart units, each group of Stewart units includes a Hooke's hinge, a ball hinge and an electric push rod, the first end of the Hooke's hinge is connected to the moving platform, the second end of the Hooke's hinge is connected to the first end of the electric push rod, the second end of the electric push rod is connected to the first end of the ball hinge, and the second end of the ball hinge is connected to the static platform;

[0009] The static platform includes a second variable angle structure, a ball hinge mounting plate, and a static platform base. The second variable angle structure and the ball hinge mounting plate are evenly arranged in multiple groups around the periphery of the static platform base. The first end of the ball hinge mounting plate is connected to the static platform base, and the second end of the ball hinge mounting plate is connected to the second variable angle structure.

[0010] The first angle-changing structure and the second angle-changing structure both include a planetary reduction motor, a planetary reduction motor bracket, a coupling, a driven wheel output shaft, a driven wheel frame, and a driven wheel; the planetary reduction motor is mounted on the planetary reduction motor bracket, the driven wheel is mounted on the driven wheel frame, the output shaft of the planetary reduction motor is connected to the driven wheel output shaft through a coupling so as to transmit torque to the driven wheel output shaft, the driven wheel output shaft is connected to the driven wheel frame, and the driven wheel output shaft drives the driven wheel to change the angle between the driven wheel and the overall rotation axis of the robot, thereby realizing switching between precession and creeping travel modes;

[0011] The diameter-changing structure includes a spring, a sliding portion, a baffle, and a base. The spring is installed inside the base. The sliding portion is arranged above the spring and can move inside the base under the support of the spring. The baffle is installed at the end of the base to limit the sliding portion. The sliding portion slides inside the base to change the diameter of the rotating assembly.

[0012] During rotational movement, the planetary reduction motor adjusts the angle between the passive wheel of the first variable angle structure and the robot's own rotation axis to 45°, and the angle between the passive wheel of the second variable angle structure and the robot's own rotation axis to 0°. The AC reduction motor in the moving platform drives the rotating component to rotate through the output shaft of the rotating component, and moves forward by relying on the friction force component generated between the passive wheel and the inner wall of the pipe; when the robot encounters an obstacle and cannot achieve rotational movement, first adjust the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 0°, and the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 90°. After the rotating component is pushed forward a certain distance by relying on the extension and contraction of the Stewart mechanism, the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis is adjusted to 90°, and the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis is adjusted to 0°. The static platform is driven forward a certain distance by relying on the extension and contraction of the Stewart mechanism to complete a peristaltic cycle, and the above peristaltic cycle is repeated to achieve peristaltic movement;

[0013] During precession motion, the calculation formula for the robot's travel speed v (m / s) in a straight pipe is as follows:

[0014] v=2πnR0tanα

[0015] Where α is the angle between the passive wheel and the overall rotation axis of the robot; n (r / s) is the speed of the AC reduction motor;

[0016] The calculation formula for the robot's travel speed v (m / s) in a curved pipe is as follows:

[0017]

[0018] Where φ is the angle that the rotating component rotates in the pipe, R is the radius of the rotor, and R0 is the radius of the elbow.

[0019] Preferably, the anti-jamming base is provided with a fastening screw, the first end of the output shaft of the rotating component is installed in the hole of the moving platform base through a bearing, the second end of the output shaft of the rotating component is installed in the axial hole of the anti-jamming base, and the fastening screw is installed in the threaded through hole of the anti-jamming base. The end of the fastening screw contacts the output shaft of the rotating component, and by tightening the fastening screw, friction can be generated at the contact surface of the two, and the torque of the output shaft of the rotating component is transmitted to the anti-jamming base with the help of friction; if the rotating component is blocked due to an obstacle, the contact surface between the fastening screw and the output shaft of the rotating component will slide relative to each other.

[0020] Preferably, the first end of the variable diameter structure and the anti-jamming base, the second end of the variable diameter structure and the first angle-changing structure, the first end of the ball hinge mounting plate and the static platform base, and the second end of the ball hinge mounting plate and the second angle-changing structure are all connected by bolts.

[0021] Preferably, the Hooke's hinge is connected to the electric push rod via a pin, the electric push rod is connected to the ball hinge via a pin, the Hooke's hinge is connected to the Hooke's hinge mounting plate via a bolt, and the ball hinge 3 is connected to the ball hinge mounting plate via a bolt.

[0022] Preferably, the AC reduction motor is mounted on the AC reduction motor bracket by means of bolts, and the AC reduction motor bracket is mounted on the moving platform base by means of bolts.

[0023] Preferably, three groups of the first angle-variable structures and diameter-variable structures are evenly arranged on the periphery of the anti-rotation-blocking base.

[0024] Preferably, three groups of the second variable angle structures and the ball hinge mounting plates are evenly arranged on the periphery of the static platform base.

[0025] Preferably, the Stewart mechanism includes six groups of Stewart units.

[0026] On the other hand, the present invention provides a method for moving a pipeline inspection robot with dual drive of precession and peristalsis based on a Stewart mechanism, which comprises the following steps:

[0027] S1: Rotate and advance in the pipe. Use the planetary reduction motor to adjust the angle between the passive wheel of the first variable angle structure and the robot's own rotation axis to 45°. Adjust the angle between the passive wheel of the second variable angle structure and the robot's own rotation axis to 0°. The AC reduction motor in the moving platform drives the rotating assembly to rotate through the rotating assembly output shaft. The robot advances by relying on the friction force generated between the passive wheel and the inner wall of the pipe.

[0028] S2: When the robot encounters an obstacle, it creeps forward, which includes the following sub-steps:

[0029] S21. Adjust the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 0°, and adjust the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 90°, and push the rotating assembly forward a certain distance by relying on the extension and retraction of the Stewart mechanism;

[0030] S22, adjusting the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 90°, and adjusting the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 0°, and relying on the extension and retraction of the Stewart mechanism to drive the static platform forward a certain distance to complete a peristaltic cycle;

[0031] S23, repeating the above steps S21 and S22 to perform a peristaltic cycle to achieve peristaltic movement;

[0032] S3. After crossing the obstacle, resume the rotational movement.

[0033] Preferably, the speed calculation method of the rotational progress is as follows:

[0034] The calculation formula for the robot's travel speed v (m / s) in a straight pipe is as follows:

[0035] v=2πnR0tanα

[0036] Where α is the angle between the passive wheel and the overall rotation axis of the robot; n (r / s) is the speed of the AC reduction motor;

[0037] The calculation formula for the robot's travel speed v (m / s) in a curved pipe is as follows:

[0038]

[0039] Where φ is the angle that the rotating component rotates in the pipe, R is the radius of the rotor, and R0 is the radius of the elbow.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The robot with dual driving modes of precession and creep proposed in the present invention has two driving modes, creeping and precession. It can select the forward direction at the tee and can adapt to the turning radius at the curved pipe. It can adapt to various pipe inner diameters when moving, and can overcome obstacles by switching creeping. It can select different travel speeds at straight pipes and curved pipes to meet various pipeline transportation needs.

[0042] (2) The robot proposed in the present invention can select the direction of advance at the tee of the pipeline, which improves the flexibility and adaptability of the robot in the pipeline.

[0043] (3) The robot proposed in the present invention can adapt to the turning radius of curved pipes, that is, the robot can carry more detection equipment that has position requirements. Compared with traditional existing robots, the robot proposed in the present invention has higher universality and can be applied to a variety of scenarios.

[0044] (4) Compared with traditional robots that have only a single driving mode, this robot has two driving modes, which gives the robot more options when encountering obstacles in the pipeline and can overcome obstacles more quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the overall structure of the pipeline inspection robot with dual drive of precession and peristalsis based on the Stewart mechanism of the present invention;

[0046] Figure 2 This is an axonometric diagram of the overall structure of the Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to the present invention;

[0047] Figure 3 It is a schematic diagram of the variable angle structure of the present invention;

[0048] Figure 4 It is a schematic diagram of the variable diameter structure of the present invention;

[0049] Figure 5 This is a schematic diagram of the anti-rotation blocking base of the present invention;

[0050] Figure 6 It is a schematic diagram of the structure of the dynamic platform of the present invention;

[0051] Figure 7 It is a schematic diagram of the static platform structure of the present invention.

[0052] Some of the reference numerals in the figure are as follows: 1-rotating assembly, 2-moving platform, 3-Stewart mechanism, 4-static platform, 101-variable angle structure, 102-variable diameter structure, 103-anti-blocking base, 201-moving platform base, 202-Hook's hinge mounting plate, 203-coupling, 204-AC reduction motor bracket, 205-AC reduction motor, 301-Hook's hinge, 302-electric push rod, 303-ball hinge, 401-variable angle structure, 402 -Ball hinge mounting plate, 403-static platform base, 10101-passive wheel, 10102-passive wheel frame, 10103-passive wheel output shaft, 10104-coupling, 10105-planetary reduction motor bracket, 10106-planetary reduction motor, 10201-spring, 10202-base, 10203-sliding part, 10204-baffle, 10301-fastening screw, 10302-base, 10303-rotating component output shaft. DETAILED DESCRIPTION

[0053] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0054] like Figure 1As shown, the present invention provides an overall structure of an in-pipeline inspection robot based on a Stewart mechanism and featuring dual drive modes of precession and peristalsis. The robot comprises a rotating assembly 1, a moving platform 2, a Stewart mechanism 3, and a stationary platform 4. The rotating assembly 1 is mounted on the moving platform 2, and the Stewart mechanism 3 is disposed between the moving platform 2 and the stationary platform 4. Specifically, one end of the rotating assembly 1 is connected to the first end of the moving platform 2, the second end of the moving platform 2 is connected to the first end of the Stewart mechanism 3, and the second end of the Stewart mechanism 3 is connected to the stationary platform 4.

[0055] like Figure 2 As shown, the rotating assembly 1 includes a first variable angle structure 101, a variable diameter structure 102 and an anti-jamming base 103. The first variable angle structure 101 and the variable diameter structure 102 are evenly arranged in multiple groups on the outer periphery of the anti-jamming base 103. In this embodiment, three groups are evenly arranged. The first end of the variable diameter structure 102 is connected to the anti-jamming base 103, and the second end of the variable diameter structure 102 is connected to the first variable angle structure 102. In a specific embodiment, the first variable angle structure 101 is connected to the variable diameter structure 102 by bolts, and the variable diameter structure 102 is connected to the anti-jamming base 103 by bolts. The first variable angle structure 101 can adjust the distance between itself and the anti-jamming base 103 with the help of the variable diameter structure 102, that is, the radius of the entire rotating assembly can be adjusted with the help of the variable diameter structure 102.

[0056] like Figure 3 As shown, the first angle-variable structure 101 includes a driven gear 10101, a driven gear carrier 10102, a driven gear output shaft 10103, a coupling 10104, a planetary reduction motor bracket 10105, and a planetary reduction motor 10106. The driven gear carrier 10102 is a split carrier, with the two parts of the carrier clamping the driven gear 10101 via bolts. The driven gear carrier 10102 is connected to the driven gear output shaft 10103 via bolts. The coupling 10104 connects the driven gear output shaft 10103 to the output shaft of the planetary reduction motor 10106. The planetary reduction motor 10106 is mounted on the planetary reduction motor bracket 10105 via bolts. The planetary reduction motor 10106 transmits the torque to the passive wheel output shaft 10103 with the help of the coupling 10104. The passive wheel frame 10102 and the passive wheel output shaft 10103 are connected by bolts, so the torque can be transmitted to the passive wheel frame 10102, and then the torque is transmitted to the passive wheel 10101. Therefore, with the help of the planetary reduction motor 10106, the passive wheel 10101 can be rotated around the axis of the passive wheel output shaft 10103, and the angle between the passive wheel 10101 and the overall rotation axis of the robot can be changed to achieve angle variation.

[0057] like Figure 6As shown, the moving platform includes a moving platform base 201, a Hooke's hinge mounting plate 202, a coupling 203, an AC reduction motor bracket 204 and an AC reduction motor 205. The moving platform base 201 is connected to the Hooke's hinge mounting plate 202 by bolts, the rotating component output shaft 10303 is installed inside the moving platform base 201 through a bearing, one end of the rotating component output shaft 10303 is connected to the output shaft of the AC reduction motor 205 through the coupling 203, the AC reduction motor 205 is mounted on the AC reduction motor bracket 204 by bolts, and the AC reduction motor bracket 204 is mounted on the moving platform base 201 by bolts.

[0058] like Figure 1 As shown, the Stewart mechanism includes six Stewart components, each Stewart component includes a Hooke's hinge 301, an electric push rod 302 and a ball hinge 303, the Hooke's hinge 301 and the electric push rod 302 are connected by a pin, the electric push rod 302 and the ball hinge 303 are connected by a pin, the Hooke's hinge 301 is connected to the Hooke's hinge mounting plate 202 by a bolt, and the ball hinge 303 is connected to the ball hinge mounting plate 402 by a bolt.

[0059] like Figure 7 As shown, the static platform 4 includes a second variable angle structure 401, a ball hinge mounting plate 402 and a base 403. The structure and principle of the second variable angle structure 401 are similar to those of the Figure 3 The first angle-changing structure shown is the same, the angle-changing structure 401 is connected to the ball hinge mounting plate 402 by bolts, and the ball hinge mounting plate 402 is connected to the base 403 by bolts.

[0060] With the help of the first and second variable angle structures, two modes of movement, namely precession and creep, can be realized. During the precession movement, the planetary reduction motor 10106 can be used to adjust the included angle between the passive wheel 10101 in the rotating component 1 and the robot's own rotation axis to 45°, and the included angle between the passive wheel 10101 in the static platform 4 and the robot's own rotation axis is 45°. The AC reduction motor 205 in the dynamic platform 2 drives the rotating component 1 to rotate through the coupling 203 and the rotating component output shaft 10303, and the robot moves forward by the friction force generated between the passive wheel 10101 and the inner wall of the pipe; when the robot encounters an obstacle and cannot precess, the included angle between the passive wheel 10101 in the rotating component 1 and the robot's own rotation axis can be changed to 0°, and the static platform 4 can be adjusted to 0°. The angle between the passive wheel in the platform 4 and the robot's own rotation axis is changed to 90°. At this time, since the angle between the passive wheel in the static platform 4 and the robot's own rotation axis is 90°, the static platform 4 cannot move along the pipeline axis. Therefore, relying on the extension and contraction of the Stewart mechanism 3, after pushing the rotating component 1 forward a certain distance, the angle between the passive wheel 10101 in the rotating component 1 and the robot's own rotation axis is changed to 90°, and the angle between the passive wheel in the static platform 4 and the robot's own rotation axis is changed to 0°. At this time, the rotating component 1 cannot move along the pipeline axis, and the Stewart mechanism 3 drives the static platform 4 forward a certain distance, realizing a peristaltic cycle. Repeating the above peristaltic cycle can realize peristaltic movement.

[0061] like Figure 4 As shown, the variable diameter structure includes a spring 10201, a base 10202, a sliding part 10203 and a baffle 10204. The spring 10201 is installed inside the base 10202. The sliding part 10204 can cooperate with the spring 10201 to slide inside the base 10202, so it can adapt to pipes of different diameters. The baffle 10204 is installed at the end of the base 10202 to prevent the sliding part 10203 from sliding out of the base 10202.

[0062] like Figure 5 and Figure 6As shown, the anti-blocking base includes a fastening screw 10301, an anti-blocking base 10302 and a rotating assembly output shaft 10303. The first end of the rotating assembly output shaft 10303 passes through the bearing and is connected to the coupling 203 through the hole of the movable platform base 201 of the movable platform 2. The coupling 203 is connected to the output shaft of the AC reduction motor 205; the second end of the rotating assembly output shaft 10303 is installed in the shaft hole of the anti-blocking base 10302, and the fastening screw 10301 is installed in the anti-blocking base 1 In the threaded through hole 0302, the end of the fastening screw 10301 contacts the passive wheel output shaft 10303. By tightening the fastening screw 10301, friction can be generated at the contact surface of the two, thereby transmitting torque and driving the rotating component to rotate. If the rotating component is blocked due to an obstacle, this form of torque transmission by friction will fail, that is, relative sliding will occur at the contact surface of the fastening screw 10301 and the passive wheel output shaft 10303, and the AC reduction motor 205 will not be blocked, thereby achieving the function of protecting the motor.

[0063] AC reduction motor 205 drives the output shaft 10303 of the rotating assembly through coupling 203, which in turn drives the rotating assembly 1 to rotate, thereby achieving the robot's precession motion. The relationship between the speed n (r / s) of AC reduction motor 205 and the robot's travel speed v (m / s) in the straight pipe can be expressed as follows:

[0064] v=2πnR0tanα

[0065] Where α is the angle between the passive wheel 10101 and the overall rotation axis of the robot.

[0066] The relationship between the rotation speed n (r / s) of the AC reduction motor 205 and the travel speed v (m / s) of the robot in the curved pipe can be expressed by the following formula:

[0067]

[0068] Where, the angle that the rotating component 1 rotates in the pipeline is φ, R is the radius of the rotor, R0 is the radius of the elbow,

[0069] The working principle of the present invention is described in detail below with reference to specific application examples:

[0070] This embodiment is used for the interior of pipelines where the transport medium is toxic and hazardous substances (such as strong acids, strong bases, strong oxidizing substances, and volatile substances). The present invention can be used with other detection elements (such as cameras) in the pipeline to detect possible defects inside the pipeline. Its working process includes the following steps:

[0071] S1. Rotate and move in the pipeline. The planetary reduction motor adjusts the angle between the passive wheel of the first variable angle structure and the robot's own rotation axis to 45°. The angle between the passive wheel of the second variable angle structure and the robot's own rotation axis is adjusted to 0°. The AC reduction motor in the dynamic platform drives the rotating component to rotate through the output shaft of the rotating component. The robot moves forward relying on the friction force generated between the passive wheel and the inner wall of the pipeline.

[0072] S2. When the robot encounters an obstacle, it creeps forward:

[0073] S21. Adjust the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 0°, and adjust the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 90°, and rely on the extension and retraction of the Stewart mechanism to push the rotating assembly forward a certain distance.

[0074] S22. Adjust the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 90°, and adjust the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 0°. Rely on the extension and retraction of the Stewart mechanism to drive the static platform forward a certain distance to complete a peristaltic cycle.

[0075] S23, repeating the above steps S21 and S22 to perform a peristaltic cycle to achieve peristaltic movement;

[0076] S3. After crossing the obstacle, resume the rotation.

[0077] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A pipeline inspection robot with dual drive of precession and peristalsis based on a Stewart mechanism, characterized by: It includes a rotating assembly, a moving platform, a Stewart mechanism and a static platform, wherein the rotating assembly is connected to a first end of the moving platform, a second end of the moving platform is connected to a first end of the Stewart mechanism, and a second end of the Stewart mechanism is connected to the static platform respectively; The rotating assembly includes a first angle-changing structure, a diameter-changing structure, a rotating assembly output shaft, and an anti-blocking base. The first angle-changing structure and the diameter-changing structure are evenly arranged in multiple groups on the periphery of the anti-blocking base. The first end of the diameter-changing structure is connected to the anti-blocking base, and the second end of the diameter-changing structure is connected to the first angle-changing structure. The rotating assembly output shaft is arranged on the anti-blocking base. The moving platform includes an AC reduction motor, a rotating assembly output shaft, a coupling, an AC reduction motor bracket, a Hooke's hinge mounting plate, and a moving platform base. The moving platform base is connected to the anti-blocking base. The AC reduction motor is mounted on the AC reduction motor bracket. The AC reduction motor bracket and the Hooke's hinge mounting plate are both mounted on the moving platform base. The output shaft of the AC reduction motor is connected to the output shaft of the rotating assembly through a coupling. The Stewart mechanism includes multiple groups of Stewart units, each group of Stewart units includes a Hooke's hinge, a ball hinge and an electric push rod, the first end of the Hooke's hinge is connected to the moving platform, the second end of the Hooke's hinge is connected to the first end of the electric push rod, the second end of the electric push rod is connected to the first end of the ball hinge, and the second end of the ball hinge is connected to the static platform; The static platform includes a second variable angle structure, a ball hinge mounting plate, and a static platform base. The second variable angle structure and the ball hinge mounting plate are evenly arranged in multiple groups around the periphery of the static platform base. The first end of the ball hinge mounting plate is connected to the static platform base, and the second end of the ball hinge mounting plate is connected to the second variable angle structure. The first angle-changing structure and the second angle-changing structure both include a planetary reduction motor, a planetary reduction motor bracket, a coupling, a driven wheel output shaft, a driven wheel frame, and a driven wheel; the planetary reduction motor is mounted on the planetary reduction motor bracket, the driven wheel is mounted on the driven wheel frame, the output shaft of the planetary reduction motor is connected to the driven wheel output shaft through a coupling so as to transmit torque to the driven wheel output shaft, the driven wheel output shaft is connected to the driven wheel frame, and the driven wheel output shaft drives the driven wheel to change the angle between the driven wheel and the overall rotation axis of the robot, thereby realizing switching between precession and creeping travel modes; The diameter-changing structure includes a spring, a sliding portion, a baffle, and a base. The spring is installed inside the base. The sliding portion is arranged above the spring and can move inside the base under the support of the spring. The baffle is installed at the end of the base to limit the sliding portion. The sliding portion slides inside the base to change the diameter of the rotating assembly. During rotational movement, the planetary reduction motor adjusts the angle between the passive wheel of the first variable angle structure and the robot's own rotation axis to 45°, and the angle between the passive wheel of the second variable angle structure and the robot's own rotation axis to 0°. The AC reduction motor in the moving platform drives the rotating component to rotate through the output shaft of the rotating component, and moves forward by relying on the friction force component generated between the passive wheel and the inner wall of the pipe; when the robot encounters an obstacle and cannot achieve rotational movement, first adjust the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 0°, and the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 90°. After the rotating component is pushed forward a certain distance by relying on the extension and contraction of the Stewart mechanism, the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis is adjusted to 90°, and the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis is adjusted to 0°. The static platform is driven forward a certain distance by relying on the extension and contraction of the Stewart mechanism to complete a peristaltic cycle, and the above peristaltic cycle is repeated to achieve peristaltic movement; During precession motion, the calculation formula for the robot's travel speed v (m / s) in a straight pipe is as follows: v=2πnR0tanα Where α is the angle between the passive wheel and the overall rotation axis of the robot; n (r / s) is the speed of the AC reduction motor; The calculation formula for the robot's travel speed v (m / s) in a curved pipe is as follows: Where φ is the angle that the rotating component rotates in the pipe, R is the radius of the rotor, and R0 is the radius of the elbow. The first end of the variable diameter structure and the anti-jamming base, the second end of the variable diameter structure and the first angle-changing structure, the first end of the ball hinge mounting plate and the static platform base, and the second end of the ball hinge mounting plate and the second angle-changing structure are all connected by bolts.

2. The Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to claim 1, characterized in that: The anti-blocking base is provided with a fastening screw, the first end of the output shaft of the rotating component is installed in the hole of the moving platform base through a bearing, the second end of the output shaft of the rotating component is installed in the axial hole of the anti-blocking base, and the fastening screw is installed in the threaded through hole of the anti-blocking base. The end of the fastening screw contacts the output shaft of the rotating component. By tightening the fastening screw, friction can be generated at the contact surface of the two, and the torque of the output shaft of the rotating component is transmitted to the anti-blocking base with the help of friction; if the rotating component is blocked due to an obstacle, the contact surface of the fastening screw and the output shaft of the rotating component will slide relative to each other.

3. The Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to claim 1, characterized in that: The Hooke's hinge is connected to the electric push rod via a pin, the electric push rod is connected to the ball hinge via a pin, the Hooke's hinge is connected to the Hooke's hinge mounting plate via a bolt, and the ball hinge 3 is connected to the ball hinge mounting plate via a bolt.

4. The Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to claim 1, characterized in that: The AC reduction motor is mounted on the AC reduction motor bracket through bolts, and the AC reduction motor bracket is mounted on the moving platform base through bolts.

5. The Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to claim 1, characterized in that: The first angle-changing structures and diameter-changing structures are evenly arranged in three groups on the periphery of the anti-rotation-blocking base.

6. The Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to claim 1, characterized in that: The second variable angle structure and the ball hinge mounting plate are evenly arranged in three groups on the periphery of the static platform base.

7. The Stewart mechanism-based dual-drive pipeline inspection robot of claim 1, characterized in that: The Stewart mechanism includes six groups of Stewart units.

8. A method for moving a pipeline inspection robot with dual drive of precession and peristalsis based on a Stewart mechanism according to claim 1, characterized in that: It includes the following steps: S1: Rotate and advance in the pipe. Use the planetary reduction motor to adjust the angle between the passive wheel of the first variable angle structure and the robot's own rotation axis to 45°. Adjust the angle between the passive wheel of the second variable angle structure and the robot's own rotation axis to 0°. The AC reduction motor in the moving platform drives the rotating assembly to rotate through the rotating assembly output shaft. The robot advances by relying on the friction force generated between the passive wheel and the inner wall of the pipe. S2: When the robot encounters an obstacle, it creeps forward, which includes the following sub-steps: S21. Adjust the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 0°, and adjust the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 90°, and push the rotating assembly forward a certain distance by relying on the extension and retraction of the Stewart mechanism; S22, adjusting the angle between the passive wheel in the first variable angle structure and the robot's own rotation axis to 90°, and adjusting the angle between the passive wheel in the second variable angle structure and the robot's own rotation axis to 0°, and relying on the extension and retraction of the Stewart mechanism to drive the static platform forward a certain distance to complete a peristaltic cycle; S23, repeating steps S21 and S22 to perform a peristaltic cycle to achieve peristaltic movement; S3. After crossing the obstacle, resume the rotational movement.

9. The moving method of the Stewart mechanism-based pipeline inspection robot with dual drive of precession and peristalsis according to claim 8, characterized in that: The speed of the rotational movement is calculated as follows: The calculation formula for the robot's travel speed v (m / s) in a straight pipe is as follows: v=2πnR0tanα Where α is the angle between the passive wheel and the overall rotation axis of the robot; n (r / s) is the speed of the AC reduction motor; The calculation formula for the robot's travel speed v (m / s) in a curved pipe is as follows: Where φ is the angle that the rotating component rotates in the pipe, R is the radius of the rotor, and R0 is the radius of the elbow.

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