Mechanical locking type inchworm bionic pipeline crawling device and method

Abstract

The invention discloses a mechanical locking type inchworm bionic pipeline crawling device and method.The mechanical locking type inchworm bionic pipeline crawling device comprises walking mechanisms, a mechanical locking mechanism and a dynamic error elimination mechanism, the number of the walking mechanisms is two, each walking mechanism comprises a working bin, a driving motor and a left-right-handed lead screw, one end of each left-right-handed lead screw is connected with the corresponding driving motor, and the other end of each left-right-handed lead screw is connected with the corresponding mechanical locking mechanism; a left-handed nut and a right-handed nut are respectively arranged on the left-handed lead screw and the right-handed lead screw, the left-handed nut and the right-handed nut are respectively connected with one ends of two connecting rods in a hinged manner, and the other ends of the four connecting rods are respectively connected with an upper supporting shoe and a lower supporting shoe in a hinged manner in pairs, so that a symmetrical quadrilateral structure is formed; the real-time error elimination mechanism is arranged between the two working bins, and the mechanical locking mechanism is arranged between left-handed nuts of the two walking mechanisms. Automatic switching of the locking / unlocking state is achieved through a pure mechanical structure, anti-explosion potential safety hazards are thoroughly eliminated, pipe diameter changes are self-adapted through gravity deformation, and displacement accumulative errors are avoided.

Description

Technical Field

[0001] This invention relates to a technology for crawling robots inside pipes, and more particularly to a mechanically locked inchworm-inspired bionic pipe crawling device and method. Background Technology

[0002] Pipelines, as a crucial infrastructure in modern society, are widely used in oil, natural gas, chemical, and municipal industries. However, long-term operation inevitably leads to defects such as corrosion, cracks, and blockages, requiring regular inspection and maintenance. Traditional pipeline inspection methods rely primarily on manual labor or large equipment, resulting in low efficiency, high costs, and significant risks, especially for complex pipeline networks and small-diameter pipelines, where traditional methods are inadequate. In recent years, pipeline robotics technology has rapidly developed, providing new solutions for pipeline maintenance. Pipeline robots can move autonomously inside pipelines, carrying various sensors and tools to perform tasks such as pipeline defect detection, cleaning, and repair, offering advantages such as high efficiency, safety, and low cost.

[0003] However, existing pipeline robots cannot solve three major problems simultaneously: (a) Instability of motion in a vertical pipe under gravity; (b) Accumulated step displacement error caused by pipe diameter variation; (c) The electric interlocking mechanism requires continuous power supply, which poses a potential explosion-proof safety hazard; the electromagnetic pin is prone to malfunction in a vibrating environment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a mechanically locked bionic pipe crawling device and method that is reasonably designed, has good stability and strong adaptability.

[0005] The technical solution of this invention is: A mechanically locked, inchworm-inspired pipe-crawling device includes a walking mechanism, a mechanical locking mechanism, and a dynamic error-eliminating mechanism. The walking mechanism comprises two sets, each including a working chamber, a drive motor, and left- and right-hand screws. One end of the working chamber is closed, and the other end is open. The drive motor is located in the closed chamber, and the left- and right-hand screws are mounted in the open chamber via concentric brackets. One end of each screw is connected to the drive motor, and a left-hand nut and a right-hand nut are respectively mounted on the left-hand screw. A hinge is mounted on the left-hand nut. The shaft has two connecting rods, one end of which is mounted on a hinge shaft to form a hinged connection. The right-hand nut also has a hinge shaft, and the other two connecting rods have one end mounted on this hinge shaft, also forming a hinged connection. The other ends of the four connecting rods are paired to form upper and lower ends, which are respectively connected to the upper and lower support shoes via axle pins to form a hinged connection. The left-hand nut, right-hand nut, two support shoes, and four connecting rods form a symmetrical quadrilateral structure. The dynamic differential elimination mechanism is provided between the working chambers of the two traveling mechanisms, and the mechanical locking mechanism is provided between the two left-hand nuts of the two traveling mechanisms.

[0006] Furthermore: the dynamic error correction mechanism includes a force-applying spring and a force-applying guide pin, wherein the two ends of the force-applying spring are respectively connected to the two working chambers of the two traveling mechanisms, and the two working chambers are respectively provided with limit plates. The two ends of the force-applying guide pin pass through the through holes of the two limit plates, and the two are slidably connected. In addition, the two ends of the force-applying guide pin are provided with fixing plates, and the force-applying spring is fitted on the force-applying guide pin; there is at least one force-applying spring and one force-applying guide pin.

[0007] Furthermore, the mechanical locking mechanism includes a locking cylindrical pin and a locking connecting piece. One end of the locking connecting piece is provided with a fixing hole, and the other end is provided with an elongated hole. The fixing hole is fitted onto a hinge shaft on a left-handed nut of a traveling mechanism to form a hinge connection. The elongated hole is fitted onto the locking cylindrical pin on a left-handed nut of another traveling mechanism to form a sliding connection. The inner and outer sides of the elongated hole form two limit positions.

[0008] Further: Suppose that the weight w1 of one of the walking mechanisms causes the deformation of the force-applying spring to be dw1, and the weight w2 of the other walking mechanism causes the deformation of the force-applying spring to be dw2, then: the length L of the elongated hole on the locking connecting piece = the diameter of the locking cylindrical pin + dw1 + dw2.

[0009] Furthermore: the drive shaft of the drive motor extends out of the closed chamber, and a sealing mechanism is provided between them. The outer end of the drive shaft is connected to one end of the left and right screws through a coupling. The upper and lower end walls of the open chamber are respectively provided with strip holes to facilitate the extension of the support shoe and connecting rod to support the inner wall of the pipe.

[0010] Furthermore: the support shoe is made of rubber material, or a composite of metal and rubber material, and the pitch of the left and right thread pairs on the left and right screws is equal.

[0011] A method for mechanically locking inchworm bionic pipe crawling using any of the described mechanically locking inchworm bionic pipe crawling devices, comprising: Figure 1 Looking from left to right, clockwise rotation of the lead screw is called right-hand rotation, and counterclockwise rotation is called left-hand rotation. The walking mechanism on the left is step shoe 2, and the walking mechanism on the right is step shoe 1. The pipe is placed vertically to the ground and includes the following steps: a. When the device is placed inside the pipe, and both the right-hand nut and the left-hand nut are in the unlocked state, the drive motor drives the left and right screws to rotate clockwise. The right-hand nut moves to the left and the left-hand nut moves to the right. That is, the right-hand nut and the left-hand nut move symmetrically closer together, and the support shoe is in a raised and supported state, which can support the inner wall of the pipe. b. When the motor drives the left and right screws to rotate counterclockwise, the left screw nut moves to the left and the right screw nut moves to the right. That is, the left and right screw nuts separate symmetrically, and the support shoe is in a lowered and retracted state, disengaging from the inner wall of the pipe. c. When one of the traveling mechanisms is tightened against the pipe wall and the other traveling mechanism is in a tightened state, and the two left-handed nuts are fixed by the mechanical locking mechanism and are stationary relative to the pipe, when the drive motor of this traveling mechanism drives the left and right-handed screws to rotate counterclockwise, the left and right-handed screws move to the right, so the traveling mechanism moves forward. d. When one of the traveling mechanisms is bracing the pipe wall and the other traveling mechanism is in a retracted state, and the two left-handed nuts are fixed by the mechanical locking mechanism and are stationary relative to the pipe, when the drive motor of the other traveling mechanism drives the left and right-handed screws to rotate clockwise, the left and right-handed screws move to the left, so the traveling mechanism moves backward. e. The drive motors of the two walking mechanisms rotate alternately, causing the entire device to move forward or backward continuously.

[0012] Furthermore: The two walking mechanisms are referred to as stepping shoe 1 and stepping shoe 2, respectively. When placed horizontally, there is no gravity between stepping shoe 1 and stepping shoe 2, and the static distance between the two bodies is B0. During the movement, the actual distance between the two bodies is B. Both stepping shoe 1 and stepping shoe 2 systems are in a retracted state, and their support shoes are located symmetrically in the middle of the left and right screws. The step distance of stepping shoe 1 is dx1, and the step distance of stepping shoe 2 is dx2. When perpendicular to the ground, the change in the distance between the shoe 1 and the shoe 2 caused by gravity is defined as dw. Then, under the action of gravity, when one of the shoes is tightened, B = B0 + dw or B = B0 - dw.

[0013] Furthermore: when the distance B between the shoe 1 and the shoe 2 > B0 + δ, the force-applying spring forcibly pulls back the shoes to achieve reset; when B < B0 - δ, the force-applying spring pushes the two shoes to perform displacement compensation to achieve reset; δ = dxmax + dw1 + dw2, where dxmax is the maximum value of the current step distance dx. The length L of the long hole = the diameter of the locking cylindrical pin + dw1 + dw2.

[0014] Furthermore: the whole device is placed in a vertical pipe, with the shoe 1 below and the shoe 2 above. The downward steps are as follows: (0) Downward initial state: The shoe 1 is anchored. The shoe 1 is tightened and in front in the downward direction; the shoe 2 is retracted and behind in the downward direction; B = B0 - dw2, and the force-applying spring is compressed. (1) First downward step: The shoe 2 is anchored in place. The second motor rotates the left-right screw rod to the right → the second shoe support is pushed up until tightened → the second motor is turned off. At this time, B = B0 - dw2, and the force-applying spring is compressed. (2) Second downward step: The shoe 1 is retracted and the shoe 1 advances. The first motor rotates the screw rod counterclockwise → the first shoe support is retracted → the shoe 1 is retracted in place → the first motor is turned off. The shoe 1 moves downward under the combined action of its own gravity w1 and the thrust of the force-applying spring. Finally, B = B0 + dw1, and the force-applying spring is stretched; the shoe 1 advances B0 + dw1 - (B0 - dw2) = dw1 + dw2. (3) Third downward step: The shoe 1 is tightened and the shoe 1 is anchored in place. The first motor rotates the screw rod clockwise → the first shoe support is pushed up → the shoe 1 is tightened → the first motor is turned off. At this time, B = B0 + dw1, and the force-applying spring is stretched; the shoe 1 advances 0. (4) Fourth downward step: The shoe 2 is retracted and the shoe 2 follows. The second motor rotates the screw rod counterclockwise → the second shoe support is retracted → the shoe 2 slides downward under the combined action of its own gravity w2 and the thrust of the force-applying spring → the second shoe support is retracted in place → the first motor is turned off. At this time, B = B0 - dw2, and the force-applying spring is compressed. The upward steps are as follows: (0) Upward initial state: The shoe 1 is anchored. Step shoe 1 is stretched and located behind in the upward direction; step shoe 2 is folded and located in front in the upward direction; B=B0-dw2, design a suitable left-hand locking connecting piece length so that the elongated hole on the connecting piece is fitted onto the locking cylindrical pin, and the cylindrical pin is located inside the elongated hole. (1) First step of ascent: Boot 2 moves forward, Boot 2 anchors. The second motor rotates the right-hand screw → the second support shoe lifts upwards → the cylindrical pin locks against the inside of the elongated hole → the step shoe 2 moves upwards by dx until it is fully supported → the second motor shuts off. At this time, B = B0 - dw2 + dx, and the force spring is stretched; the step shoe 2 moves forward by dx. The design requires dx > dw1 + dw2 to ensure an effective forward step distance. (2) Second step of ascending: Boot 1 gathers and follows, The first motor rotates the screw to the left → the step shoe 1 retracts → the step shoe 1 slides down under the combined action of its own weight w1 and the force spring → the long hole follows down → the cylindrical pin unlocks → the step shoe 1 retracts into place → the first motor is turned off → the cylindrical pin moves to the outside of the long hole and locks, at this time B=B0+dw1, and the force spring is stretched. (3) Third step of ascent: tighten step boot 1, anchor step boot 1, The first motor rotates the right-hand screw → the first support shoe is lifted upwards → the cylindrical pin is locked against the outside of the long hole → the step shoe 1 moves forward dx until it is fully supported → the first motor is turned off. At this time, B=B0+dw1-dx, and the force spring is compressed. (4) Fourth step of ascending: Boot 2 moves forward, Boot 2 retracts. The second motor rotates the screw to the left → the second support shoe retracts downwards → the step shoe 2 slides down under the combined action of its own weight w2 and the force of the spring → the cylindrical pin unlocks → the second support shoe retracts into place → the first motor shuts off → the cylindrical pin slides down to the inside of the elongated hole and locks, at this time B=B0-dw2, the spring is compressed; the step shoe 2 moves forward B0-dw2-(B0+dw1-dx)=dx-dw1-dw2.

[0015] The beneficial effects of this invention are: 1. This invention achieves automatic switching between locked and unlocked states through a purely mechanical structure, completely eliminating explosion-proof safety hazards, and utilizes gravity deformation to adapt to changes in pipe diameter, avoiding cumulative displacement errors.

[0016] 2. The present invention adopts a structure of left-handed nut, right-handed nut and left-handed and right-handed screw, which can quickly realize the opening or retraction of the support boot, and the walking efficiency is high.

[0017] 3. The directional limiting sliding pair engagement of the cylindrical pin and the elongated hole in this invention improves vibration resistance by 3 times and enhances stability.

[0018] 4. The drive motor, control circuit, power supply, etc. of this invention are located in a sealed space and will not be corroded by liquids or debris in the pipes, resulting in high safety and long service life.

[0019] 5. The present invention uses a force-applying guide pin, which can both guide the force and prevent the force-applying spring from becoming unstable under pressure, thus avoiding problems with the force-applying spring.

[0020] 6. This invention features precise self-adaptation, matching the position of the cylindrical pin with the amount of gravitational deformation, and automatically compensating for displacement errors when the pipe diameter changes; it also optimizes energy efficiency, utilizing gravitational potential energy during the unlocking process to reduce the motor load by more than 20%.

[0021] 7. This invention adopts a inchworm-inspired structure, which allows for stable movement on uneven surfaces and adaptability to varying pipe diameters. It has a wide range of applications, is easy to promote and implement, and has good economic benefits. Attached Figure Description

[0022] Figure 1 A schematic diagram of a mechanically locked inchworm biomimetic pipe crawling device; Figure 2 for Figure 1 Enlarged view of a portion of the image; Figure 3 for Figure 1 The diagram shows the initial downward state of a mechanically locked inchworm bionic pipe crawling device. Figure 4 This is the state diagram for the first step of the downlink process; Figure 5 This is the state diagram for the second step of the downlink; Figure 6 This is the state diagram for the third step of the downlink; Figure 7 This is the state diagram for the fourth step of the downlink process; Figure 8 for Figure 1 The image shows the initial upward movement of a mechanically locked inchworm bionic pipe crawling device. Figure 9 This is the state diagram for the first step of the upward movement; Figure 10 This is the state diagram for the second step of the upward movement; Figure 11 This is the state diagram for the third step of the upward movement; Figure 12 This is the state diagram for the fourth step of the upward movement. Detailed Implementation

[0023] Example: See Figure 1 -- Figure 12 In the picture: 1-Pipeline; 2-Second working chamber; 3-Second motor; 4-Second coupling; 6-Second support shoe; 7-Second connecting rod; 8-Left-hand locking connecting piece; 9-Force-applying spring; 10-First support shoe; 11-First connecting rod; 12-First right-hand nut; 13-First coupling; 14-First working chamber; 15-First motor; 17-First left-hand nut; 18-Force-applying guide pin; 20-Second right-hand nut; 21-Second left-hand nut; 24-Second left-hand and right-hand screw; 25-Second concentric bracket; 26-First concentric bracket; 27-First left-hand and right-hand screw.

[0024] 5-Locking cylindrical pin, fixed on the second left-hand nut, forming a locking relationship with the inner or outer side of the elongated hole on the locking connecting piece; 8-Locking connecting piece, the connecting piece has an elongated hole on the second left-hand nut side and a fixing hole on the first left-hand nut side; 8-1, the fixing hole on the locking connecting piece is assembled on the hinge shaft of the first left-hand nut to form a hinge connection; 8-2, the elongated hole on the connecting piece is assembled on the locking cylindrical pin of the second left-hand nut to form a sliding connection; 8-3, the inner position of the elongated hole; 8-4, the outer position of the elongated hole; 23-First left-hand nut shaft pin, fixed on the first left-hand nut.

[0025] A mechanically locked, inchworm-inspired pipe-crawling device includes a walking mechanism, a mechanical locking mechanism, and a dynamic error-eliminating mechanism. The walking mechanism consists of two sets, each including a working chamber, a drive motor, and left and right helical screws. One end of the working chamber is closed, and the other end is open. The drive motor (including control circuitry and power supply) is located in the closed chamber. The left and right helical screws are mounted in the open chamber via concentric brackets. One end of each screw is connected to the drive motor. A left-handed nut and a right-handed nut are respectively mounted on the left and right helical screws, with a hinge on the left-handed nut. The shaft has two connecting rods, one end of which is mounted on a hinge shaft to form a hinged connection. A right-hand nut also has a hinge shaft, and the other two connecting rods have one end mounted on this hinge shaft, also forming a hinged connection. The other ends of the four connecting rods are respectively connected to the upper and lower support shoes via axle pins to form a hinged connection. The left-hand nut, right-hand nut, two support shoes, and four connecting rods form a symmetrical quadrilateral structure. A dynamic differential correction mechanism is provided between the working chambers of the two traveling mechanisms, and a mechanical locking mechanism is provided between the two left-hand nuts of the two traveling mechanisms.

[0026] Preferred solution: The dynamic error correction mechanism includes a force-applying spring 9 and a force-applying guide pin 18. The two ends of the force-applying spring 9 are connected to the two working chambers of the two traveling mechanisms, respectively. Limit plates are installed in each of the two working chambers. The two ends of the force-applying guide pin 18 pass through through holes in the two limit plates, forming a sliding connection. Fixing plates are provided at both ends of the force-applying guide pin 18 to prevent it from dislodging. The error correction spring 8 is fitted onto the force-applying guide pin 18. There is at least one force-applying spring 9 and at least two force-applying guide pins 18 (two are shown in the figure, but one or four are also possible, etc.). The parallel force-applying guide pins 18 and the force-applying spring 9 ensure that the two machine bodies are coaxial and do not rotate relative to each other.

[0027] Preferred solution: The mechanical locking mechanism includes a locking cylindrical pin 5 and a locking connecting piece 8. One end of the locking connecting piece 8 is provided with a fixing hole 8-1, and the other end is provided with an elongated hole 8-2. The fixing hole 8-1 is fitted onto the hinge shaft on the left-hand nut of a traveling mechanism to form a hinge connection. The elongated hole 8-2 is fitted onto the locking cylindrical pin 5 on the left-hand nut of another traveling mechanism to form a sliding connection. The inner side 8-3 and the outer side 8-4 of the elongated hole 8-2 form two limit positions.

[0028] Preferred solution: Suppose that the weight w1 of one traveling mechanism causes the deformation of the force-applying spring to be dw1, and the weight w2 of the other traveling mechanism causes the deformation of the force-applying spring to be dw2, then: the length L of the elongated hole 8-2 on the locking connecting piece 8 = the diameter of the locking cylindrical pin + dw1 + dw2.

[0029] Preferred solution: The drive shaft of the drive motor extends out of the closed chamber, and a sealing mechanism is provided between the two. The outer end of the drive shaft is connected to one end of the left and right screws through a coupling. The upper and lower end walls of the open chamber are respectively provided with strip holes to facilitate the extension of the support shoe and connecting rod to support the inner wall of the pipe.

[0030] Preferred solution: The support shoe is made of rubber material, or a combination of metal and rubber material. The left and right pitches of the lead screws are equal, and the pitches of the left and right nuts are also equal.

[0031] The components of the first traveling mechanism include: 10-First support shoe; 11-First connecting rod; 12-First right-hand nut; 13-First coupling; 14-First working chamber; 15-First motor; 17-First left-hand nut; 26-First concentric bracket; 27-First left-hand and right-hand lead screw; The components of the second traveling mechanism include: 2-Second working chamber; 3-Second motor; 4-Second coupling; 6-Second support shoe; 7-Second connecting rod; 20-Second right-hand nut; 21-Second left-hand nut; 24-Second left-right turn screw; 25-Second concentric bracket; The components of a mechanical locking mechanism include: 5-Locking cylindrical pin, fixed on the second left-hand nut, forming a locking relationship with the inner or outer side of the elongated hole on the locking connecting piece; 8-Locking connecting piece, the connecting piece has an elongated hole on the second left-hand nut side and a fixing hole on the first left-hand nut side; 8-1, the fixing hole on the locking connecting piece is assembled on the hinge shaft of the first left-hand nut to form a hinge connection; 8-2, the elongated hole on the connecting piece is assembled on the locking cylindrical pin of the second left-hand nut to form a sliding connection; 8-3, the inner position of the elongated hole; 8-4, the outer position of the elongated hole; 23-First left-hand nut shaft pin, fixed on the first left-hand nut.

[0032] A mechanically locked inchworm biomimetic pipe crawling method, for simplicity, refers to two walking mechanisms as walking boot 1 and walking boot 2. Figure 1 In the diagram, viewed from left to right, clockwise rotation of the left-hand and right-hand lead screws is called right-hand rotation, and counterclockwise rotation is called left-hand rotation. The left-hand and right-hand lead screws have equal pitches for their left and right thread pairs, with half being left-hand and half being right-hand. When the output shaft of the drive motor rotates, the lead screw can rotate, while the left (right) nut does not rotate but can move left and right along the threaded lead screw. The entire device is called a robot.

[0033] 1. Setup and Instructions: Before entering the pipe, the robot is placed horizontally, without gravity, and the force spring is in a non-stressed state. The body clearance B between step shoe 1 and step shoe 2 is B0. Both step shoe 1 and step shoe 2 are in a retracted state, and their support shoes are located symmetrically in the middle of the left and right threaded screws. The step distance of step shoe 1 is dx1, and the step distance of step shoe 2 is dx2. When the ground is perpendicular, the change in the distance between boot 1 and boot 2 due to gravity is defined as dw. Then, under the action of gravity, when one of the boots is stretched, B = B0 + dw or B = B0 - dw.

[0034] 2. Action steps: a. When the device is placed inside the pipe, and both the right-hand nut and the left-hand nut are in the unlocked state, the drive motor drives the left and right screws to rotate clockwise. The right-hand nut moves to the left and the left-hand nut moves to the right. That is, the right-hand nut and the left-hand nut move symmetrically closer together, and the support shoe is in a raised and supported state, which can support the inner wall of the pipe. b. When the motor drives the left and right screws to rotate counterclockwise, the left screw nut moves to the left and the right screw nut moves to the right. That is, the left and right screw nuts separate symmetrically, and the support shoe is in a lowered and retracted state, disengaging from the inner wall of the pipe. c. When one traveling mechanism presses against the pipe wall, the other traveling mechanism is in a tightened state, and the two left-handed nuts are fixed by a mechanical locking mechanism and are stationary relative to the pipe. When the driving motor of this traveling mechanism drives the left-right screw rod to rotate counterclockwise, the left-right screw rod moves to the right direction, so this traveling mechanism moves forward; d. When one traveling mechanism presses against the pipe wall, the other traveling mechanism is in a retracted state, and the two left-handed nuts are fixed by a mechanical locking mechanism and are stationary relative to the pipe. When the driving motor of the other traveling mechanism drives the left-right screw rod to rotate clockwise, the left-right screw rod moves to the left direction, so this traveling mechanism moves backward; e. The driving motors of the two traveling mechanisms rotate alternately, causing the entire device to move forward or backward continuously.

[0035] 3. Limit conditions: When the distance B between the shoe 1 and the shoe 2 is B > B0 + δ, the force-applying spring forcibly pulls back the shoes to achieve reset; when B < B0 - δ, the force-applying spring pushes the two shoes to perform displacement compensation to achieve reset; δ = dxmax + dw1 + dw2, where dxmax is the maximum value of the current step distance dx; The length L of the long slot = the diameter of the locking cylindrical pin + dw1 + dw2.

[0036] 4. Specific steps: The entire device is placed into a vertical pipe, with the shoe 1 at the bottom and the shoe 2 at the top. The downward movement steps are as follows: (0). Initial state of downward movement: The shoe 1 is anchored. The shoe 1 is tightened and in front in the downward direction; the shoe 2 is retracted and behind in the downward direction; B = B0 - dw2, and the force-applying spring is compressed; see Figure 3 .

[0037] (1). First step of downward movement: The shoe 2 is anchored in place. The second motor makes the left-right screw rod rotate rightward → the second shoe is pushed up until it is tightened → the second motor is turned off. At this time, B = B0 - dw2, and the force-applying spring is compressed; see Figure 4 . (2). Second step of downward movement: The shoe 1 is retracted and the shoe 1 moves forward. The first motor rotates the left screw rod → the first shoe is retracted → the shoe 1 is retracted in place → the first motor is turned off. The shoe 1 moves under the combined action of its own gravity w1 and the thrust of the force-applying spring. Finally, B = B0 + dw1, and the force-applying spring is stretched; the shoe 1 moves forward by B0 + dw1 - (B0 - dw2) = dw1 + dw2; see Figure 5 . (3). Third step of downward movement: The shoe 1 is tightened and the shoe 1 is anchored in place. The first motor rotates the right-hand lead screw → the first support shoe lifts upwards → the step shoe 1 tightens → the first motor shuts off. At this point, B = B0 + dw1, and the force spring is stretched; the step shoe 1 advances 0 degrees. (See also...) Figure 6 .

[0038] (4) Fourth step of descent: Step 2 retracts, Step 2 follows, The second motor rotates the lead screw to the left → the second support shoe retracts → the step shoe 2 slides down under the combined action of its own weight w2 and the force of the applying spring → the second support shoe retracts into place → the first motor shuts off, at this time B = B0 - dw2, and the applying spring is compressed; see also Figure 7 .

[0039] The uplink steps are as follows: (0) Initial state of ascent: Boot 1 is anchored. Step shoe 1 is taut and positioned behind in the upward direction; step shoe 2 is folded and positioned in front in the upward direction; B = B0 - dw2, design a suitable length for the left-hand locking connecting piece so that the elongated hole on the connecting piece is fitted onto the locking cylindrical pin, and the cylindrical pin is positioned inside the elongated hole; see [reference]. Figure 8 .

[0040] (1) First step of ascent: Boot 2 moves forward, Boot 2 anchors. The second motor rotates the right-hand lead screw → the second support shoe lifts upwards → the cylindrical pin locks against the inside of the elongated hole → the step shoe 2 moves upwards by dx until it is fully supported → the second motor shuts off. At this point, B = B0 - dw2 + dx, and the force spring is stretched; the step shoe 2 moves forward by dx. The design requires dx > dw1 + dw2 to ensure effective forward movement. See [reference needed] Figure 9 .

[0041] (2) Second step of ascending: Boot 1 gathers and follows, The first motor rotates the lead screw to the left → Step shoe 1 retracts → Step shoe 1 slides down under the combined action of its own weight w1 and the thrust of the force spring → The elongated hole follows suit → The cylindrical pin unlocks → Step shoe 1 retracts into place → The first motor shuts off → The cylindrical pin moves to the outside of the elongated hole and locks, at which point B = B0 + dw1, and the force spring is under tension; see also Figure 10 .

[0042] (3) Third step of ascent: tighten step boot 1, anchor step boot 1, The first motor rotates the right-hand lead screw → the first support shoe lifts upwards → the cylindrical pin locks against the outside of the elongated hole → the step shoe 1 moves forward dx until it is fully supported → the first motor shuts off, at this time B = B0 + dw1 - dx, and the force spring is compressed; see also Figure 11 .

[0043] (4) Fourth step of ascending: Boot 2 moves forward, Boot 2 retracts. The second motor rotates the lead screw to the left → the second support shoe retracts downwards → the step shoe 2 slides down under the combined action of its own weight w2 and the force spring → the cylindrical pin unlocks → the second support shoe retracts into place → the first motor shuts off → the cylindrical pin slides down to the inside of the elongated hole and locks, at this time B = B0 - dw2, the force spring is compressed; the step shoe 2 advances B0 - dw2 - (B0 + dw1 - dx) = dx - dw1 - dw2. (See also...) Figure 12 .

[0044] 5. Key parameter design:

[0045] 6. Passive error control: When the difference in pipe diameter (D1≠D2) causes a deviation in the step displacement of the two-step shoe system, the spacing B is automatically reset by the action of the force spring's push / pull force.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications made based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A mechanically locked inchworm-inspired pipe crawling device, comprising a walking mechanism, a mechanical locking mechanism, and a dynamic error correction mechanism, characterized in that: The traveling mechanism consists of two sets, each including a working chamber, a drive motor, and left and right helical screws. One end of the working chamber is closed, and the other end is open. The drive motor is located in the closed chamber, and the left and right helical screws are mounted in the open chamber via concentric brackets. One end of each screw is connected to the drive motor. A left-handed nut and a right-handed nut are respectively mounted on the left-handed screw. A hinge shaft is mounted on the left-handed nut, and one end of two connecting rods is mounted on the hinge shaft, forming a hinged connection. A hinge shaft is also mounted on the right-handed nut, and one end of two other connecting rods is mounted on the same hinge shaft, also forming a hinged connection. The other ends of the four connecting rods are paired to form upper and lower ends, respectively, and are hinged to the upper and lower support shoes via pins. The left-handed nut, right-handed nut, two support shoes, and four connecting rods form a symmetrical quadrilateral structure. A dynamic differential correction mechanism is provided between the working chambers of the two traveling mechanisms, and a mechanical locking mechanism is provided between the two left-handed nuts of the two traveling mechanisms.

2. The mechanically locked inchworm bionic pipe crawling device according to claim 1, characterized in that: The dynamic error correction mechanism includes a force-applying spring and a force-applying guide pin. The two ends of the force-applying spring are respectively connected to the two working chambers of the two traveling mechanisms. Limit plates are respectively provided in the two working chambers. The two ends of the force-applying guide pin pass through the through holes of the two limit plates and are slidably connected. Furthermore, the two ends of the force-applying guide pin are provided with fixing plates. The force-applying spring is fitted on the force-applying guide pin. There is at least one force-applying spring and one force-applying guide pin.

3. The mechanically locked inchworm bionic pipe crawling device according to claim 1, characterized in that: The mechanical locking mechanism includes a locking cylindrical pin and a locking connecting piece. One end of the locking connecting piece is provided with a fixing hole, and the other end is provided with an elongated hole. The fixing hole is fitted onto a hinge shaft on a left-handed nut of a traveling mechanism to form a hinge connection. The elongated hole is fitted onto the locking cylindrical pin on a left-handed nut of another traveling mechanism to form a sliding connection. The inner and outer sides of the elongated hole form two limit positions.

4. The mechanically locked inchworm bionic pipe crawling device according to claim 3, characterized in that: a... The weight w1 of the walking mechanism causes the force spring to deform into dw1, while the weight w2 of the other walking mechanism causes the force spring to deform into dw2. Therefore, the length L of the elongated hole on the locking connecting piece is equal to the diameter of the locking cylindrical pin plus dw1 plus dw2.

5. The mechanically locked inchworm bionic pipe crawling device according to claim 1, characterized in that: The drive shaft of the drive motor extends out of the closed chamber, and a sealing mechanism is provided between them. The outer end of the drive shaft is connected to one end of the left and right screw via a coupling. The upper and lower end walls of the open chamber are respectively provided with strip-shaped holes to facilitate the extension of the support shoe and connecting rod to support the inner wall of the pipe.

6. The mechanically locked inchworm bionic pipe crawling device according to claim 1, characterized in that: The support shoe is made of rubber material, or a combination of metal and rubber material, and the left and right thread pitches on the left and right screws are equal.

7. A mechanical locking inchworm bionic pipeline crawling method using the mechanical locking inchworm bionic pipeline crawling device described in any one of claims 1-6. When the left and right-handed screw rotates clockwise, it is called right-handed rotation, and when it rotates counterclockwise, it is called left-handed rotation. The walking mechanism on the left side of the figure is the step boot 2, and the walking mechanism on the right side is the step boot 1. The pipeline is placed vertically on the ground. The method includes the following steps: a. Place the device into the pipeline. When both the right-handed nut and the left-handed nut are in the unlocked state, when the driving motor drives the left and right-handed screw to rotate clockwise, the right-handed nut moves to the left, and the left-handed nut moves to the right. That is, the right-handed nut and the left-handed nut move symmetrically closer, and the support boots are in a state of being propped up and can support the inner wall of the pipeline. b. When the motor drives the left and right-handed screw to rotate counterclockwise, the left-handed nut moves to the left, and the right-handed nut moves to the right. That is, the left-handed nut and the right-handed nut move symmetrically apart, and the support boots are in a state of being lowered and retracted, disengaging from the inner wall of the pipeline. c. When one of the walking mechanisms is tightly pressed against the pipe wall and the other walking mechanism is in a tightened state, and the two left-handed nuts are fixed by the mechanical locking mechanism and are stationary relative to the pipeline, when the driving motor of this walking mechanism drives the left and right-handed screw to rotate counterclockwise, the left and right-handed screw moves to the right direction, so this walking mechanism moves forward. d. When one of the walking mechanisms is tightly pressed against the pipe wall and the other walking mechanism is in a retracted state, and the two left-handed nuts are fixed by the mechanical locking mechanism and are stationary relative to the pipeline, when the driving motor of the other walking mechanism drives the left and right-handed screw to rotate clockwise, the left and right-handed screw moves to the left direction, so this walking mechanism moves backward. e. The driving motors of the two walking mechanisms rotate alternately, causing the entire device to move forward or backward continuously.

8. A mechanically locked inchworm biomimetic pipe crawling method according to claim 7, characterized in that: two The walking mechanisms are respectively called step boot 1 and step boot 2. When placed horizontally, there is no gravity acting between step boot 1 and step boot 2, and the static distance between the two bodies is B0. During the movement, the actual distance between the two bodies is B. The step boots of both step boot 1 and step boot 2 systems are in a retracted state, and their support boots are located at the symmetric position in the middle of the left and right-handed screw. The step distance of step boot 1 is dx1, and the step distance of step boot 2 is dx2. When perpendicular to the ground, the change in the distance between step boot 1 and step boot 2 caused by gravity is defined as dw. Then, under the action of gravity, when one of the step boots is tightly pressed, B = B0 + dw or B = B0 - dw.

9. The mechanically locked inchworm biomimetic pipe crawling method according to claim 8, characterized in that: When the distance B between step boot 1 and step boot 2 > B0 + δ, the force-applying spring forcibly pulls back the step boots to achieve reset; when B < B0 - δ, the force-applying spring pushes the two step boots to perform displacement compensation to achieve reset; δ = dxmax + dw1 + dw2, where dxmax is the maximum value of the current step distance dx. The length L of the long hole = the diameter of the locking cylindrical pin + dw1 + dw2.

10. The mechanically locked inchworm biomimetic pipe crawling method according to claim 8, characterized in that: The entire device is placed into a vertical pipeline, with step boot 1 below and step boot 2 above. The steps for descending are as follows: (0). Initial state of descending: Step boot 1 is anchored. Step boot 1 is tightly pressed and in front in the descending direction; step boot 2 is retracted and behind in the descending direction; B = B0 - dw2, and the force-applying spring is compressed. (1). First step of descending: Step boot 2 is anchored in place. The second motor causes the left and right screws to rotate to the right → the second support shoe is lifted up until it is tightened → the second motor is turned off. At this time, B=B0-dw2, and the force spring is compressed. (2) Second step of descent: Boot 1 retracts, Boot 1 moves forward. The first motor rotates the left screw → the first support shoe retracts → the step shoe 1 retracts into place → the first motor is turned off. The step shoe 1 moves downward under the combined action of its own weight w1 and the force of the force spring. Finally, B = B0 + dw1, and the force spring is stretched. The step shoe 1 moves forward B0 + dw1 - (B0 - dw2) = dw1 + dw2. (3) Third step of descent: tighten step boot 1, anchor step boot 1 in place, The first motor rotates the right-hand screw → the first support shoe lifts upwards → the step shoe 1 tightens → the first motor shuts off. At this time, B = B0 + dw1, and the force spring is stretched; the step shoe 1 moves forward 0. (4) Fourth step of descent: Step 2 retracts, Step 2 follows, The second motor rotates the lead screw to the left → the second support shoe retracts → the step shoe 2 slides down under the combined action of its own weight w2 and the force spring → the second support shoe retracts into place → the first motor is turned off. At this time, B=B0-dw2 and the force spring is compressed. The uplink steps are as follows: (0) Initial state of ascent: Boot 1 is anchored. Step shoe 1 is stretched and located behind in the upward direction; step shoe 2 is folded and located in front in the upward direction; B=B0-dw2, design a suitable left-hand locking connecting piece length so that the elongated hole on the connecting piece is fitted onto the locking cylindrical pin, and the cylindrical pin is located inside the elongated hole. (1) First step of ascent: Boot 2 moves forward, Boot 2 anchors. The second motor rotates the right-hand screw → the second support shoe lifts upwards → the cylindrical pin locks against the inside of the elongated hole → the step shoe 2 moves upwards by dx until it is fully supported → the second motor shuts off. At this time, B = B0 - dw2 + dx, and the force spring is stretched; the step shoe 2 moves forward by dx. The design requires dx > dw1 + dw2 to ensure an effective forward step distance. (2) Second step of ascending: Boot 1 gathers and follows, The first motor rotates the screw to the left → the step shoe 1 retracts → the step shoe 1 slides down under the combined action of its own weight w1 and the force spring → the long hole follows down → the cylindrical pin unlocks → the step shoe 1 retracts into place → the first motor is turned off → the cylindrical pin moves to the outside of the long hole and locks, at this time B=B0+dw1, and the force spring is stretched. (3) Third step of ascent: tighten step boot 1, anchor step boot 1, The first motor rotates the right-hand screw → the first support shoe is lifted upwards → the cylindrical pin is locked against the outside of the long hole → the step shoe 1 moves forward dx until it is fully supported → the first motor is turned off. At this time, B=B0+dw1-dx, and the force spring is compressed. (4) Fourth step of ascending: Boot 2 moves forward, Boot 2 retracts. The second motor rotates the screw to the left → the second support shoe retracts downwards → the step shoe 2 slides down under the combined action of its own weight w2 and the force of the spring → the cylindrical pin unlocks → the second support shoe retracts into place → the first motor shuts off → the cylindrical pin slides down to the inside of the elongated hole and locks, at this time B=B0-dw2, the spring is compressed; the step shoe 2 moves forward B0-dw2-(B0+dw1-dx)=dx-dw1-dw2.

Images