In-pipe mobile robot

Abstract

The present invention provides an in-tube mobile robot (1), comprising a robot body (10) including at least three telescopic units (11). The in-tube mobile robot (1) is characterized by having: an end posture maintaining part (20) having an end body part (21) and a pair of elastic bodies (22, 23), the end body part (21) constituting the end of the in-tube mobile robot (1), each pair of elastic bodies (22, 23) protruding radially outward from the outer peripheral surface of the end body part (21) and spaced apart from each other in the axial direction; an elastic connecting part (40) disposed between the end posture maintaining part (20) and the robot body (10) and capable of elastic deformation; and an angle limiting joint part (30) disposed between the elastic connecting part (40) and the robot body (10), such that the end posture maintaining part (20) can bend relative to the robot body (10) at an angle of less than 90 degrees.

Description

Technical Field

[0001] This invention relates to an intra-tube mobile robot that moves inside a tube. Prior Technology

[0002] For example, there is a known pipe-moving robot configured to move inside curved pipes such as air ducts for air conditioning systems installed in office buildings, factories, detached houses, etc. (see, for example, Patent Document 1). This pipe-moving robot is used for various purposes such as cleaning and inspecting the inside of pipes. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Publication No. 2020-507486 Summary of the Invention

[0004] The problem that the invention aims to solve One type of pipe-moving robot comprises a robot body with at least three telescopic units. Each telescopic unit expands radially and contracts axially upon fluid supply. The at least three telescopic units perform peristaltic movements in a predetermined pattern, thereby enabling the pipe-moving robot to move inside the pipe. In this type of pipe-moving robot, to facilitate smooth passage through curved sections of the pipe, a tapered tip is typically provided at the front end of the robot body via a compression spring.

[0005] However, even if the robot body is configured with a tapered tip portion at the front end via a compression spring, if there is a step difference such as the connection portion of the elbow constituting the bend portion on the inner circumferential surface of the tube, the tip portion may get stuck on the step difference, preventing the robot from moving forward inside the tube.

[0006] The present invention was made in view of this problem, and its object is to provide a robot capable of reliably moving inside a tube through the curved portion of a tube. Technical means to solve the problem

[0007] The in-tube mobile robot of the present invention comprises a robot body including at least three telescopic units. Each telescopic unit expands radially and contracts axially upon fluid supply. The telescopic units perform peristaltic motion in a predetermined pattern, thereby enabling the in-tube mobile robot to move inside the tube. The in-tube mobile robot is characterized by having a tip posture maintaining section, an elastic connecting section, and an angle-limiting joint. The tip posture maintaining section includes: a tip body portion constituting the tip of the in-tube mobile robot; and a pair of elastic bodies, each elastic body being a generally circular or polygonal ring centered on the axis of the tip body portion, protruding radially outward from the outer peripheral surface of the tip body portion, and spaced apart from each other axially. The elastic connecting section is disposed between the tip posture maintaining section and the robot body and is elastically deformable. The angle-limiting joint is disposed between the elastic connecting section and the robot body, allowing the tip posture maintaining section to bend relative to the robot body at an angle of less than 90 degrees.

[0008] The in-tube mobile robot of the present invention comprises a robot body including at least three telescopic units. Each telescopic unit expands radially and contracts axially upon fluid supply. The telescopic units perform peristaltic motion in a predetermined pattern, thereby enabling the in-tube mobile robot to move inside the tube. The in-tube mobile robot is characterized by having a tip posture maintaining portion and an elastic connecting portion. The tip posture maintaining portion includes: a tip body portion constituting the tip of the in-tube mobile robot; and a pair of elastic bodies, each elastic body being a generally annular or polygonal ring centered on the axis of the tip body portion, protruding radially outward from the outer peripheral surface of the tip body portion, and spaced apart from each other axially. The elastic connecting portion is disposed between the tip posture maintaining portion and the robot body and is elastically deformable. The tip body portion has a protruding portion protruding forward from the pair of elastic bodies, the protruding portion retracting within a virtual sphere inscribed in the entire circumference by the outer peripheral ends of each of the pair of elastic bodies.

[0009] The in-tube mobile robot of the present invention is configured to include a robot body comprising at least three telescopic units, each of which expands radially and contracts axially upon fluid supply. The telescopic units perform peristaltic motion in a predetermined pattern, thereby enabling the in-tube mobile robot to move within a tube. The in-tube mobile robot is characterized by having a tip posture-maintaining portion and an elastic connecting portion. The tip posture-maintaining portion comprises: a tip body portion constituting the tip of the in-tube mobile robot; and a pair of elastic bodies, each elastic body being a generally circular or polygonal ring centered on the axis of the tip body portion, protruding radially outward from the outer peripheral surface of the tip body portion, and spaced apart from each other axially. The elastic connecting portion is disposed between the tip posture-maintaining portion and the robot body and is elastically deformable. The elastic body on the rear side is more flexible than the elastic body on the front side.

[0010] In the above-described structure, the in-tube mobile robot of the present invention preferably has a protruding portion protruding forward from a pair of the elastomers, and a camera is disposed on the axis of the protruding portion.

[0011] The in-tube mobile robot of the present invention, in the above-described structure, preferably has a cover, the cover comprising: an inner cylindrical body, which is stretchable and formed into a cylinder; and an outer cylindrical body, which is stretchable and formed into a cylinder, overlapping and disposed outside the inner cylindrical body. The frictional resistance generated between the inner cylindrical body and the outer cylindrical body is less than the frictional resistance generated between the outer cylindrical body and the inner surface of the tube. The cover covers the angle-limiting joint. The effects of the invention

[0012] According to the present invention, a robot capable of reliably moving inside a tube can be provided. Simple Explanation of the Diagram

[0013] Figure 1 is a side view of the tube-mounted mobile robot of the first embodiment of the present invention. Figure 2 is a schematic diagram illustrating the actuation mode of the telescopic unit during the peristaltic motion of the robot body shown in Figure 1. Figure 3 is an enlarged side view of the main part of the tube-moving robot shown in Figure 1. Figure 4 is a diagram showing the state of the robot moving inside the tube when the tip posture maintenance unit moves in the curved part of the tube. Figures 5(a) to (f) are explanatory diagrams showing how the tip posture maintenance part moves in the curved part of the tube. Figure 6 is a diagram showing the state of the robot moving inside the tube when the angle-limited joint begins to move in the curved part of the tube. Figure 7 is a diagram showing the state of the robot moving inside the tube when the angle-limited joint ends its movement in the curved part of the tube. Figure 8 is an enlarged side view showing the main part of the tube-moving robot of the second embodiment of the present invention. Figure 9 is a cross-sectional view along line AA in Figure 8. Figure 10 is an explanatory diagram showing the state of the cover shown in Figure 9 as it passes through the curved section of the tube. Figure 11 is an enlarged side view showing the main part of the tube-moving robot of the third embodiment of the present invention. Figures 12(a) to (c) are explanatory diagrams of the angle-limiting joint in the state where the position of the stop has been changed. Figure 13 is an enlarged side view showing the main part of the tube-mounted mobile robot of the fourth embodiment of the present invention. Figures 14(a) to (f) are explanatory diagrams showing how the tip posture maintaining part shown in Figure 13 moves in the curved part of the tube. Implementation

[0014] The tube-moving robot of the present invention will now be described in detail with reference to the illustrations.

[0015] Figure 1 shows a tube-moving robot 1 according to a first embodiment of the present invention, configured to move inside a curved tube, such as an air duct for an air conditioning device installed in an office building, factory, or detached house.

[0016] The in-tube mobile robot 1 has a robot body 10, an end posture maintenance part 20, an angle limiting joint part 30, and an elastic connection part 40.

[0017] The robot body 10, also known as an earthworm-type robot or a worm-like robot, has an elongated shape extending along axis O. The robot body 10 is capable of moving axially within the tube, i.e., along axis O. That is, the robot body 10 can move forward within the tube. Alternatively, the robot body 10 can also be configured to move forward and backward within the tube.

[0018] The robot body 10, serving as a drive source for movement within the tube, includes at least three telescopic units 11. In this embodiment, the robot body 10 includes seven telescopic units 11 (only four telescopic units 11 are shown in Figure 1). Furthermore, as long as the robot body 10 includes at least three telescopic units 11, the number of telescopic units 11 can be appropriately varied.

[0019] The telescopic unit 11 is also called an artificial muscle. The telescopic unit 11 has a cylindrical portion 11a formed from various elastomers such as rubber, centered on an axis O. Both ends of the cylindrical portion 11a are closed along the axial direction. Inside the cylindrical portion 11a, multiple fiber bundles (not shown) with high tensile strength are arranged axially. This allows the cylindrical portion 11a to elastically deform radially, but its elastic deformation in the axial direction is limited. Therefore, when a fluid such as compressed air is supplied to the inside of the cylindrical portion 11a, the telescopic unit 11 expands radially and contracts axially. Furthermore, when the fluid is discharged from the inside of the cylindrical portion 11a, the telescopic unit 11 contracts radially and extends axially by the elastic force of the cylindrical portion 11a, thus returning to its original shape. Each telescopic unit 11 can operate individually in a predetermined pattern.

[0020] In addition, the telescopic unit 11 can be of various structures, such as a so-called McKibben type, in which a cylindrical elastomer is covered with a sleeve-shaped fiber, as long as it is configured to expand radially and contract axially when fluid is supplied.

[0021] Adjacent telescopic units 11 are axially connected to each other via connecting portions 12. In this embodiment, the connecting portion 12 is a universal joint. As a result, the robot body 10 can bend at the connecting portion 12. Therefore, when the robot body 10 moves inside the tube, even if the tube is bent, adjacent telescopic units 11 can bend at the connecting portion 12, thereby enabling movement along the bent tube.

[0022] In this embodiment, a universal joint is used as the connecting part 12, but it is not limited to any component that can bend and connect adjacent telescopic units 11.

[0023] The robot body 10 is connected to a control unit 14 via a pipe 13. The control unit 14 can individually supply fluid to the inside of the cylindrical portion 11a of each telescopic unit 11 in a predetermined pattern via the pipe 13. By supplying fluid from the control unit 14 to the inside of the cylindrical portion 11a of each telescopic unit 11 in a predetermined pattern, the multiple telescopic units 11 perform peristaltic movements in a predetermined pattern, and the robot body 10 can move inside the pipe.

[0024] Figure 2 shows an example of the peristaltic motion pattern of the multiple telescopic units 11 when the robot body 10 moves axially to one side inside the tube 2, i.e., when it moves to the left in Figure 2.

[0025] First, as shown in Figure 2(a), the leftmost (front) telescopic unit 11 and the second telescopic unit 11 from the left in Figure 2 are expanded radially and contracted axially. The two radially expanding telescopic units 11 abut against the inner circumferential surface of the tube 2 on the entire circumference. In this way, the robot body 10 is held axially by means of the two radially expanding telescopic units 11.

[0026] Next, from the state shown in Figure 2(a), as shown in Figure 2(b), the leftmost telescopic unit 11 is restored to its original shape, while the third telescopic unit 11 from the left expands radially and contracts axially. At this time, since the second telescopic unit 11 from the left is in contact with the inner circumferential surface of the tube 2 and its axial position is maintained, the leftmost telescopic unit 11 contracts radially and extends axially to restore its original shape, thereby moving the left end (front end) of the robot body 10 to the left from the position shown in Figure 2(a). In addition, while the second telescopic unit 11 from the left is in contact with the inner circumferential surface of the tube 2 and its axial position is maintained, the third telescopic unit 11 from the left expands radially and contracts axially, so the right end (rear end) of the robot body 10 also moves to the left from the position shown in Figure 2(a).

[0027] Next, from the state shown in Figure 2(b), as shown in Figure 2(c), the second telescopic unit 11 from the left is restored to its original shape, while the fourth telescopic unit 11 from the left expands radially and contracts axially. At this time, since the third telescopic unit 11 from the left is in contact with the inner circumferential surface of the tube 2 and its axial position is maintained, the second telescopic unit 11 from the left contracts radially and extends axially to restore its original shape, thereby moving the left end (front end) of the robot body 10 further to the left from the position shown in Figure 2(b). In addition, while the third telescopic unit 11 from the left is in contact with the inner circumferential surface of the tube 2 and its axial position is maintained, the fourth telescopic unit 11 from the left expands radially and contracts axially, so the right end (rear end) of the robot body 10 also moves further to the left from the position shown in Figure 2(b).

[0028] Next, following the same steps, the telescopic unit 11 is operated in the above-described pattern until the rightmost telescopic unit 11 is reached. Then, when the pattern reaches the rightmost telescopic unit 11, as shown in FIG2(d), the operation of the telescopic unit 11 is returned to the initial state of being operated in the above-described pattern.

[0029] Thus, by causing the multiple telescopic units 11 to move in the aforementioned pattern, the robot body 10 can move forward to the left in Figure 2 inside the tube 2. Furthermore, by causing the multiple telescopic units 11 to operate in a pattern opposite to the left-right movement shown in Figure 2, the robot body 10 can move backward to the right in Figure 2 inside the tube 2. In other words, the tube-moving robot 1, by performing the aforementioned actions, can move forward and backward inside the tube 2.

[0030] In addition, the peristaltic movement mode of the multiple telescopic units 11 in the robot body 10 is not limited to the above. As long as the robot body 10 or the robot 1 moving inside the tube can move forward or backward, other modes are also possible.

[0031] As shown in Figure 1, in this embodiment, the robot body 10 is provided with a plurality of brushes 15, which are spaced apart along the axial direction of the robot body 10. More specifically, brushes 15 are provided at both ends of each telescopic unit 11 along its axial direction. Each of the plurality of brushes 15 has a generally annular shape centered on the axis O of the robot body 10. That is, each of the plurality of brushes 15 is configured such that multiple bristles protrude radially outward from the outer peripheral surface of the robot body 10 centered on the axis O, arranged around the entire circumference in the circumferential direction centered on the axis O. The multiple bristles constituting the brushes 15 are made of a soft and elastically deformable material, such as synthetic resin. The outer diameter of the brushes 15 is approximately the same as the inner diameter of the tube 2, which is the object to which the in-tube mobile robot 1 moves. Preferably, the outer diameter of the brushes 15 is the same as or slightly larger than the inner diameter of the tube 2, which is the object to which the in-tube mobile robot 1 moves. When the in-tube mobile robot 1 moves inside the tube 2, the outer peripheral end of the brushes 15 contacts the inner peripheral surface of the tube 2.

[0032] The robot body 10, equipped with multiple brushes 15, can move along the tube 2 while being supported at approximately the center of the tube 2 by the multiple brushes 15. In addition, by equipping the robot body 10 with multiple brushes 15, it can collect debris and other foreign objects (dirt) attached to the inner circumference of the tube 2 and clean the inside of the tube 2 when moving inside the tube 2.

[0033] Furthermore, in this embodiment, the robot body 10 is provided with a plurality of brushes 15, but is not limited to brushes 15. As long as it has a generally annular shape centered on the axis O of the robot body 10, other components such as flange-shaped or umbrella-shaped synthetic rubber may also be provided. Alternatively, the robot body 10 may be configured without the plurality of brushes 15 or with other components having a generally annular shape centered on the axis O of the robot body 10.

[0034] As shown in Figures 1 and 3, the tip posture maintenance part 20, the angle limiting joint part 30, and the elastic connection part 40 are arranged on the side relative to the direction of movement of the robot body 10 (left side in Figure 3).

[0035] As shown in Figure 3, the tip posture maintenance part 20 has a tip body part 21 and a pair of elastic bodies 22 and 23.

[0036] The tip body portion 21 is the part that forms the tip (front end) of the in-tube mobile robot 1 in the direction of travel. That is, the in-tube mobile robot 1 moves forward inside the tube 2 with the tip body portion 21 as its head. The tip body portion 21 has a cylindrical body 21a centered on axis O, and a dome-shaped protrusion 21b connected to the end of the body 21a in the direction of travel and centered on axis O. The tip body portion 21 is generally conical in shape. However, the shape of the tip body portion 21 is not limited to the shape described above.

[0037] A pair of elastic bodies 22 and 23 are each configured as a generally circular ring or a ring with a polygonal outer periphery centered on axis O, protruding radially outward from the outer peripheral surface of the body section 21a of the tip body portion 21, and are spaced apart from each other axially. In this embodiment, the pair of elastic bodies 22 and 23 are each a circular ring (with a circular outer periphery) centered on axis O. The front elastic body 22 is disposed at the front end of the body section 21a of the tip body portion 21, and the rear elastic body 23 is disposed on the body section 21a at a predetermined distance rearward relative to the front elastic body 22. The axial spacing between the pair of elastic bodies 22 and 23 can be appropriately set according to the size of the tube being moved, the curvature of the bent portion, etc. The pair of elastic bodies 22 and 23 are elastically deformable in both the axial direction and the radial direction centered on axis O.

[0038] In this embodiment, the front elastic body 22 and the rear elastic body 23 have the same shape or structure. More specifically, the pair of elastic bodies 22 and 23 are annular brushes centered on the axis O of the body 21a. That is, the pair of elastic bodies 22 and 23 are each configured as having multiple bristles protruding radially outward from the outer peripheral surface of the body 21a centered on the axis O, arranged around the entire circumference in the circumferential direction centered on the axis O. The multiple bristles constituting the elastic bodies 22 and 23 are made of a soft and elastically deformable material, such as synthetic resin. The outer diameter of the elastic bodies 22 and 23 is approximately the same as the inner diameter of the tube 2, which is the object of the tube-moving robot 1. Preferably, the outer diameter of the elastic bodies 22 and 23 is the same as or slightly larger than the inner diameter of the tube 2, which is the object of the tube-moving robot 1. When the tube-moving robot 1 moves inside the tube 2, the outer peripheral ends of the elastic bodies 22 and 23 contact the inner peripheral surface of the tube 2.

[0039] The tip posture holding unit 20, by providing a pair of elastic bodies 22 and 23 spaced apart axially on the tip body 21, can move along the tube 2 while being supported at approximately the center of the tube 2 by the pair of elastic bodies 22 and 23 when moving inside the tube 2. Furthermore, when using a brush as a pair of elastic bodies 22 and 23 provided on the tip body 21, the tip posture holding unit 20 can collect debris and other foreign matter (dirt) adhering to the inner circumferential surface of the tube 2 and clean the inside of the tube 2 when moving inside the tube 2.

[0040] In this embodiment, the pair of elastic bodies 22 and 23 are annular about the axis O, but are not limited thereto. As long as the tip posture holding part 20 can be supported at approximately the center of the tube 2, they can also be configured as approximately annular, such as a D-shape with a portion of the outer periphery slightly cut off, or as an annular shape with a regular polygonal outer periphery. Furthermore, in this embodiment, a brush is used as the pair of elastic bodies 22 and 23, but are not limited thereto. As long as they have an annular shape about the axis O of the tip body part 21, such as an annular and elastically deformable component made of flanged or umbrella-shaped synthetic rubber, components of other materials or structures can also be provided.

[0041] The preferred configuration of the tip posture maintenance part 20 is as follows: the protruding portion 21b of the tip body part 21 that protrudes forward from the pair of elastic bodies 22, 23 is contained within a virtual sphere 24 (represented by a two-point chain in FIG. 3) which is inscribed in the entire circumference by the outer peripheral ends 22a, 23a of each of the pair of elastic bodies 22, 23. The virtual sphere 24 is a sphere inscribed in the outer peripheral ends 22a, 23a of each of the pair of elastic bodies 22, 23, with point 24a on the axis O at the center position between the pair of elastic bodies 22, 23, which are spaced apart along the axis O. The protruding portion 21b of the tip body part 21 does not protrude outside the virtual sphere 24, and is entirely disposed inside the virtual sphere 24.

[0042] In this embodiment, the tip posture maintenance unit 20 has a camera 25 mounted on the axis O of a protruding portion 21b that protrudes forward from the tip body 21 beyond a pair of elastic bodies 22 and 23. More specifically, the protruding portion 21b is configured as a transparent dome-shaped cover, and the camera 25 is mounted on the axis O inside it. The camera 25 faces forward, and when the in-tube mobile robot 1 moves inside the tube 2, it can capture images of the inside of the tube 2 from the front side of the tip body 21. The camera 25 can be configured, for example, to display the captured images of the inside of the tube 2 on a monitor disposed outside the tube 2. By providing such a camera 25, when the in-tube mobile robot 1 moves inside the tube 2, the state inside the tube 2 can be confirmed by the captured images from the camera 25.

[0043] Alternatively, a lighting device 26 may be installed inside the protruding part 21b to illuminate the inside of the tube 2 captured by the camera 25. For example, an LED light can be used as the lighting device 26.

[0044] An angle-limiting joint 30 is provided between the tip posture maintaining part 20 and the robot body 10. More specifically, the angle-limiting joint 30 is provided between the elastic connecting part 40 connecting the rear end of the tip posture maintaining part 20 and the robot body 10. The angle-limiting joint 30 connects the tip posture maintaining part 20 in a manner that allows it to bend relative to the robot body 10 at an angle of less than 90 degrees.

[0045] In this embodiment, the angle limiting joint 30 has a universal joint 31 and a stop 32.

[0046] Universal joint 31 is a so-called universal joint. Universal joint 31 is provided between the front fixing part 33 fixed to the rear end of the elastic connecting part 40 and the rear fixing part 34 fixed to the front end of the robot body 10, connecting the front fixing part 33 and the rear fixing part 34 so that they can rotate about a front rotation axis 35 perpendicular to the axis O, and can rotate about a rear rotation axis 36 perpendicular to the axis O and the front rotation axis 35.

[0047] The stop portion 32, supported by the universal joint portion 31, is disposed between the front fixing portion 33 and the rear fixing portion 34. The stop portion 32 is configured to abut against the front fixing portion 33 when the front fixing portion 33 has rotated less than 90 degrees relative to the axis O around the front rotation axis 35. This limits the rotation angle (bending angle) of the front fixing portion 33 relative to the axis O around the front rotation axis 35 to less than 90 degrees. Furthermore, the stop portion 32 is configured to abut against the rear fixing portion 34 when the rear fixing portion 34 has rotated less than 90 degrees relative to the axis O around the rear rotation axis 36. This limits the rotation angle (bending angle) of the rear fixing portion 34 relative to the axis O around the rear rotation axis 36 to less than 90 degrees.

[0048] Furthermore, the angle-limiting joint 30 is not limited to the structure with universal joint 31 and stop 32 described above, as long as it is a component that connects the tip posture maintaining part 20 and the robot body 10 in a manner that allows the tip posture maintaining part 20 to be bent at an angle of less than 90 degrees relative to the robot body 10. Various structures can also be used. Alternatively, it can be configured without the angle-limiting joint 30.

[0049] The elastic connection part 40 is disposed between the tip posture maintaining part 20 and the angle limiting joint part 30, connecting the tip posture maintaining part 20 and the angle limiting joint part 30. Alternatively, when the angle limiting joint part 30 is not provided, the elastic connection part 40 is disposed between the tip posture maintaining part 20 and the robot body 10, connecting the tip posture maintaining part 20 and the robot body 10.

[0050] In this embodiment, the elastic connection 40 is composed of a compression coil spring extending along the axis O. The elastic connection 40 can elastically deform in a way that contracts along the axis O. In addition, the elastic connection 40 can softly elastically deform in a way that bends relative to the axis O. Therefore, when the tip posture holding part 20 approaches the curved portion 2b of the tube 2, the elastic connection 40 elastically deforms in a way that bends relative to the axis O, thereby allowing it to bend relative to the angle limiting joint 30 in the direction along the curved portion 2b.

[0051] The elastic connection part 40 is not limited to the compression coil spring described above. It can be any component that is provided between the tip posture maintaining part 20 and the angle limiting joint part 30 and connects the two, and can be elastically deformed between the tip posture maintaining part 20 and the angle limiting joint part 30 in a bending manner relative to the axis O. It can also be other components such as rubber tubes.

[0052] As shown in Figure 4, even if the tube 2 in which the in-tube mobile robot 1 moves has a curved portion 2b between a pair of straight portions 2a, the in-tube mobile robot 1 can reliably pass through the curved portion 2b.

[0053] That is, in the tube-mounted mobile robot 1 of this embodiment, the tip posture maintenance part 20 is connected or linked to the robot body 10 via the elastic connection part 40 and the angle limiting joint part 30 and constitutes the tip of the tube-mounted mobile robot 1. On the tip body part 21 of the tip posture maintenance part 20, a pair of elastic bodies 22 and 23 are provided at intervals in the axial direction. Therefore, even if there is a step 2c at the connection between the straight part 2a and the curved part 2b of the tube 2 (see Figure 4), the tip body part 21 can move along the curved part 2b and is not easily stuck on the step 2c, and the tip body part 21 can be prevented from getting stuck in the curved part 2b of the tube 2.

[0054] More specifically, as shown in Figure 5(a), when the tip body 21 of the tip posture maintaining part 20 moves in the straight section 2a of the tube 2, a pair of elastic bodies 22 and 23 respectively abut against the inner circumferential surface of the straight section 2a of the tube 2, thereby maintaining the direction of the axis O of the tip body 21 parallel to the extension direction of the straight section 2a of the tube 2, and moving inside the tube 2. As shown in Figure 5(b), when the tip posture maintaining part 20 advances and the tip body 21 moves from the straight section 2a of the tube 2 to the curved section 2b, the front elastic body 22 abuts against the inner circumferential surface of the curved section 2b of the tube 2, while the rear elastic body 23 abuts against the inner circumferential surface of the straight section 2a of the tube 2. Therefore, the tip body 21 rotates around point 24a and begins to bend along the curved section 2b. At this time, between the tip body 21 and the angle limiting joint 30, the elastic connecting part 40 is compressed and bent elastically deformed, thereby allowing the tip body 21 to rotate relative to the angle limiting joint 30. As shown in Figure 5(c), when the tip posture maintaining part 20 advances further and the elastic body 23 on the rear side reaches the curved part 2b, the tip posture maintaining part 20 abuts against the inner circumferential surface of the curved part 2b of the tube 2 by means of a pair of elastic bodies 22 and 23 respectively. As shown in Figure 5(d), the tip body 21 rotates around point 24a and moves along the curved part 2b inside the tube 2. As shown in Figure 5(e), when the tip posture maintaining part 20 advances further and the front elastic body 22 reaches the straight part 2a through the curved part 2b, the tip posture maintaining part 20 gradually returns to the posture along the straight part 2a by abutting the inner circumferential surface of the straight part 2a of the tube 2 through the front elastic body 22, and at the same time abutting the inner circumferential surface of the curved part 2b of the tube 2 through the rear elastic body 23. Then, as shown in Figure 5(f), when the tip posture maintaining part 20 advances further and the rear elastic body 23 reaches the straight part 2a, the tip posture maintaining part 20 maintains the direction of its axis O parallel to the extension direction of the straight part 2a of the tube 2 by abutting the inner circumferential surface of the straight part 2a of the tube 2 through the pair of elastic bodies 22 and 23 respectively, and moves inside the tube 2.

[0055] Thus, in the tube-mounted mobile robot 1 of this embodiment, the tip posture maintenance part 20 is connected or linked to the robot body 10 via the elastic connection part 40 and the angle limiting joint part 30 and constitutes the tip of the tube-mounted mobile robot 1. On the tip body part 21 of the tip posture maintenance part 20, a pair of elastic bodies 22 and 23 are arranged at intervals in the axial direction. When the tube-mounted mobile robot 1 moves inside the tube 2, the pair of elastic bodies 22 and 23 abut against the inner circumferential surface of the tube 2, so that the tip body part 21 is guided in a posture along the tube 2. Therefore, the tip body part 21 can smoothly pass through the curved part 2b of the tube 2. Furthermore, in the tube-mounted robot 1 of this embodiment, as described above, by having a pair of elastic bodies 22 and 23 respectively abut against the inner circumferential surface of the tube 2, the tip body 21 is guided in a posture along the tube 2. Therefore, it is possible to prevent the tip body 21 from getting stuck in the curved portion 2b of the tube 2 and the elastic connection portion 40 from elastically deforming in a way that bends in the opposite direction toward the curved portion 2b, causing the tip body 21 to be blocked in the curved portion 2b of the tube 2.

[0056] Furthermore, in the tube-moving robot 1 of this embodiment, when the pair of elastic bodies 22 and 23 are configured as brushes, the tip body 21 smoothly passes through the curved portion 2b of the tube 2, and the pair of elastic bodies 22 and 23 provided on the tip body 21 can effectively clean the inner surfaces of both the outer and inner circumferences of the curved portion 2b of the tube 2. Moreover, when the camera 25 is configured to be mounted on the protruding portion 21b, the axis of the camera 25 can be fixed in a certain direction, and the camera 25 can capture the entire area of ​​the object to be captured inside the curved portion 2b of the tube 2.

[0057] Furthermore, in the tube-moving robot 1 of this embodiment, the tip body 21 can smoothly pass through the curved portion 2b of the tube 2, thus suppressing the following phenomenon: after the tip body 21 jams the step 2c between the straight portion 2a and the curved portion 2b of the tube 2, causing the elastic connecting portion 40 to be compressed, the elastic force of the elastic connecting portion 40 causes the tip body 21 to move violently inside the curved portion 2b as the tip body 21 releases the jamming of the step 2c. That is, the tip body 21 can smoothly pass through the curved portion 2b of the tube 2 at a predetermined moving speed. In this way, when the pair of elastic bodies 22 and 23 are configured as brushes, the pair of elastic bodies 22 and 23 provided on the tip body 21 can more effectively clean the inner surfaces of both the outer and inner circumference sides of the curved portion 2b of the tube 2. In addition, when the camera 25 is configured to be provided on the protruding portion 21b, the camera 25 can capture images of the inside of the curved portion 2b of the tube 2 without image jumps.

[0058] Furthermore, in the tube-moving robot 1 of this embodiment, the protruding portion 21b of the tip body 21 that protrudes forward from the pair of elastic bodies 22 and 23 is retracted into the range of the virtual sphere 24 inscribed in the entire circumference by the outer peripheral ends of each of the pair of elastic bodies 22 and 23. Therefore, the tip body 21 is less likely to get stuck on the curved portion 2b or the step 2c of the tube 2.

[0059] That is, as shown in Figure 5, when the tip body 21 moves through the curved portion 2b of the pipe 2, it rotates around point 24a, which is the center of the virtual sphere 24. Therefore, by retracting the protruding portion 21b into the range of the virtual sphere 24, the protruding portion 21b of the tip body 21 is less likely to abut against the inner surface of the curved portion 2b of the pipe 2 when it moves through the curved portion 2b of the pipe 2. In this way, it is possible to more effectively suppress the protruding portion 21b of the tip body 21 from forcefully abutting against the inner surface of the curved portion 2b of the pipe 2, or from blocking the step difference 2c between the straight portion 2a and the curved portion 2b. Therefore, the tip body 21 can pass through the curved portion 2b of the pipe 2 more smoothly.

[0060] Furthermore, in the tube-moving robot 1 of this embodiment, the protruding portion 21b of the tip body 21 that protrudes forward from the pair of elastic bodies 22, 23 is retracted into the area of ​​a virtual sphere 24 inscribed in the entire circumference by the outer peripheral ends 22a, 23a of each of the pair of elastic bodies 22, 23. Therefore, it is possible to prevent the protruding portion 21b from being scratched by friction against the inner surface of the curved portion 2b when the tip body 21 moves in the curved portion 2b of the tube 2. In this way, when the camera 25 is configured to be installed inside the transparent protruding portion 21b, the camera 25 can capture images of the inside of the tube 2 more clearly through the transparent protruding portion 21b.

[0061] In the tube-moving robot 1 of this embodiment, the rear-side elastic body 23 can be made into a member that is softer than the front-side elastic body 22. That is, the rear-side elastic body 23 can be configured to elastically deform more easily in the axial direction with less force than the front-side elastic body 22. As shown in Figures 5(c) and 5(d), when the tip body 21 moves in the curved portion 2b of the tube 2, the rear-side elastic body 23 abuts against the inner surface of the inner circumference of the curved portion 2b more forcefully than the front-side elastic body 22 in some cases. However, by making the rear-side elastic body 23 a member that is softer than the front-side elastic body 22, it is possible to prevent the rear-side elastic body 23 from getting stuck on the inner surface of the inner circumference of the curved portion 2b. In particular, when the curved portion 2b of the tube 2 is an injection-molded product made of resin, protrusions such as burrs generated during molding may form on the inner surface of the inner circumference side of the curved portion 2b of the tube 2. However, even in such cases, by making the elastomer 23 on the rear side a member that is softer than the elastomer 22 on the front side, it is possible to prevent the elastomer 23 on the rear side from getting stuck on the protrusions on the inner surface of the inner circumference side of the curved portion 2b. Therefore, the tip body portion 21 can pass through the curved portion 2b of the tube 2 more smoothly.

[0062] Furthermore, in the tube-moving robot 1 of this embodiment, in addition to the elastic connection portion 40, an angle-limiting joint portion 30 is provided between the tip body portion 21 and the robot body 10. Therefore, when the tip body portion 21 passes through the curved portion 2b of the tube 2, or while passing through it, the front end of the robot body 10 is less likely to get stuck on the step 2c or protrusion of the curved portion 2b. That is, in conventional components, even if the tip portion can pass through the step, the front end of the robot body may then get stuck on the step, which may cause the tube-moving robot to be unable to move forward. However, in the tube-moving robot 1 of this embodiment, by having an angle-limiting joint portion 30 in addition to the elastic connection portion 40 between the tip body portion 21 and the robot body 10, this problem can be suppressed.

[0063] More specifically, as shown in Figure 6, after the tip body 21 passes through the curved portion 2b of the tube 2, the angle-limiting joint 30, in addition to the elastic connection portion 40, also bends along the curved portion 2b between the tip body 21 and the robot body 10. This allows the robot 1, which moves within the tube, to move smoothly within the curved portion 2b between the tip body 21 and the robot body 10. At this time, the angle-limiting joint 30 is configured such that the bending angle of the tip body 21 relative to the robot body 10 is limited to less than 90 degrees by the stop portion 32 abutting against the front fixing portion 33. Therefore, it can prevent the angle-limiting joint 30 from bending to an excessive angle of more than 90 degrees and becoming buckled within the curved portion 2b. Thus, as shown in Figure 7, after the tip body 21 passes through the curved portion 2b, the angle-limiting joint 30 can be pushed into the straight portion 2a without getting stuck at the step 2c. Therefore, after the tip body 21 passes through the curved portion 2b, the angle-limiting joint 30 or the robot body 10 can also pass smoothly through the curved portion 2b.

[0064] Next, based on Figures 8, 9, and 10, the tube-mounted mobile robot 100 of the second embodiment of the present invention will be described. Furthermore, in Figures 8, 9, and 10, the same reference numerals are used to denote components or parts corresponding to the aforementioned components or parts. In addition, in the tube-mounted mobile robot 100 of the second embodiment, the structures of the robot body 10, the tip posture maintaining part 20, the angle limiting joint part 30, and the elastic connection part 40 are basically the same as those of the tube-mounted mobile robot 1 of the first embodiment, therefore, further description is omitted.

[0065] As shown in Figure 8, the difference between the second embodiment of the in-tube mobile robot 100 and the first embodiment of the in-tube mobile robot 1 is that it has a cover 50 with a coverage angle limiting joint 30.

[0066] As shown in Figure 9, the cover 50 has a dual structure consisting of an inner cylindrical body 51 and an outer cylindrical body 52. ​​The inner cylindrical body 51 is formed from a stretchable material into a cylindrical shape centered on axis O, and is coaxially arranged with the angle-limiting joint 30, covering the entire outer side of the angle-limiting joint 30. The outer cylindrical body 52 is formed from a stretchable material into a cylindrical shape with a diameter larger than that of the inner cylindrical body 51 and coaxial with the inner cylindrical body 51, overlapping and covering the entire outer side of the inner cylindrical body 51. The outer cylindrical body 52 can be configured to contact the inner cylindrical body 51, or it can be configured to have a gap between it and the inner cylindrical body 51. The folded portions at both ends of the cover 50, the inner cylindrical body 51 and the outer cylindrical body 52, are fixed to the angle-limiting joint 30 using clamping members 53 and 54. Inclined surfaces 53a and 54a are provided between the outer peripheral surface and the side surface of the clamping members 53 and 54.

[0067] In addition, the structure for fixing the cover 50 to the angle-limiting joint 30 can be appropriately modified, for example, by using straps to directly fix the ends of the inner cylindrical body 51 and the outer cylindrical body 52 to the front fixing part 33 and the rear fixing part 34.

[0068] In this embodiment, the inner cylindrical body 51 and the outer cylindrical body 52 are each made of cloth woven from nylon fibers in a prescribed pattern, and are expandable and contractible in the axial direction and radial direction centered on axis O. Since the inner cylindrical body 51 and the outer cylindrical body 52 are each made of nylon cloth with relatively low frictional resistance, the frictional resistance generated between the inner cylindrical body 51 and the outer cylindrical body 52 is smaller than the frictional resistance generated between the inner cylindrical body 51 and the angle-limiting joint 30 and between the outer cylindrical body 52 and the inner surface of the tube 2. Thus, the cover 50 is configured such that the frictional resistance generated between the inner cylindrical body 51 and the outer cylindrical body 52 is smaller than the frictional resistance generated between the outer cylindrical body 52 and the inner surface of the tube 2. Furthermore, as long as the frictional resistance generated between the inner cylindrical body 51 and the outer cylindrical body 52 is smaller than the frictional resistance generated between the outer cylindrical body 52 and the inner surface of the tube 2, the cover 50 is not limited to a cloth woven from nylon fibers in a prescribed pattern, but can also be made of other cloths or sheets.

[0069] As shown in Figure 10, when the in-tube mobile robot 100 of the second embodiment passes through the curved portion 2b of the tube 2, the angle-limiting joint 30 moves forward in a bent state, and therefore the cover 50 covering the angle-limiting joint 30 is forcefully pressed against the inner surface of the outer periphery of the tube 2. At this time, since the cover 50 has a dual structure with an inner cylindrical body 51 and an outer cylindrical body 52, even if the outer cylindrical body 52 is forcefully pressed against the inner surface of the outer periphery of the tube 2, the frictional resistance between it and the inner surface prevents it from sliding forward on the inner surface of the tube 2. However, while the outer cylindrical body 52 extends axially, the inner cylindrical body 51, which is pushed by the angle-limiting joint 30 against the outer cylindrical body 52, slides relative to the outer cylindrical body 52, thereby allowing the angle-limiting joint 30 to move slightly forward inside the tube 2. Then, the driving force generated by this slight forward movement causes the outer cylindrical body 52 to slide relative to the inner surface of the tube 2 in the forward direction, enabling the tube-moving robot 100 to move forward inside the tube 2.

[0070] Thus, since the tube-mounted mobile robot 100 in the second embodiment is configured with a cover 50 having a cover angle limiting joint 30, even when the angle limiting joint 30 is forcefully pressed inside the tube 2 when the tube-mounted mobile robot 100 passes through the curved portion 2b of the tube 2, the tube-mounted mobile robot 100 can reliably move forward.

[0071] In addition, the pressing member 53 for fixing the front side of the cover 50 is provided with an inclined surface 53a, so the pressing member 53 can cross the step 2c at the inclined surface 53a, which enables the in-tube mobile robot 100 to move forward more reliably.

[0072] Next, based on Figures 11 and 12, the tube-mounted mobile robot 200 of the third embodiment of the present invention will be described. Furthermore, in Figures 10 and 11, components or parts corresponding to the aforementioned components or parts are labeled with the same reference numerals. In addition, in the tube-mounted mobile robot 200 of the third embodiment, the structures of the robot body 10, the tip posture maintaining part 20, and the elastic connection part 40 are basically the same as those of the tube-mounted mobile robot 1 of the first embodiment, therefore, further description is omitted.

[0073] As shown in Figure 11, the difference between the third embodiment of the in-tube mobile robot 200 and the first embodiment of the in-tube mobile robot 1 is that the angle limiting joint 30 has a stop position changing device 60 that changes the position of the stop 32 in the axial direction.

[0074] In this embodiment, the stop position changing device 60 includes a cylinder 61 and a connecting body 62 fixed to a rod 61a of the cylinder 61. The connecting body 62 is connected to the stop portion 32, and the stop portion 32 and the connecting body 62 move integrally. By actuating the cylinder 61, the stop position changing device 60 can progressively change the position of the stop portion 32 to the position closest to the front fixed portion 33 shown in FIG. 12(a), the position farther from the front fixed portion 33 shown in FIG. 12(b), and the position farthest from the front fixed portion 33 shown in FIG. 12(c). Thus, by changing the position of the stop portion 32 and the distance between the stop portion 32 and the front fixed portion 33 by the stop position changing device 60, the bending angle of the angle limiting joint portion 30 can be changed to multiple angles less than 90 degrees to match the shape of the curved portion 2b of the pipe 2.

[0075] Furthermore, the position of the stop part 32 changed by the stop position changing device 60 is not limited to the three positions mentioned above, and can be set appropriately.

[0076] The stop position changing device 60 can be configured such that: based on the image captured by the camera 25 of the inside of the pipe 2, the bending angle of the bent portion 2b is determined in the control device (not shown), and based on the determination result, the control device automatically controls the operation of the cylinder 61 to make the stop portion 32 position corresponding to the bent portion 2b of the pipe 2.

[0077] Alternatively, the stop position changing device 60 can be configured to operate the connector 62 manually instead of using the cylinder 61, so that the stop portion 32 is positioned corresponding to the bent portion 2b of the pipe 2. In this case, the connector 62 can be operated manually before inserting the pipe-moving robot 200 into the pipe 2.

[0078] Next, based on Figures 13 and 14, the tube-moving robot 300 of the fourth embodiment of the present invention will be described. In Figures 13 and 14, components or parts corresponding to the aforementioned components or parts are labeled with the same symbols. Furthermore, in the tube-moving robot 300 of the fourth embodiment, the structures of the robot body 10, the angle-limiting joint 30, and the elastic connection 40 are basically the same as those of the tube-moving robot 1 of the first embodiment, therefore, further description is omitted.

[0079] As shown in Figure 13, the difference between the fourth embodiment of the in-tube mobile robot 300 and the first embodiment of the in-tube mobile robot 1 is that the tip posture maintenance unit 20, in addition to the front elastic body 22 and the rear elastic body 23, also has an intermediate elastic body 27 between the front elastic body 22 and the rear elastic body 23. More specifically, in the fourth embodiment of the in-tube mobile robot 300, the front elastic body 22 is disposed at the front end of the tip body 21, and the rear elastic body 23 is disposed at the rear end of the tip body 21. The intermediate elastic body 27 is spaced apart from both the front elastic body 22 and the rear elastic body 23. The outer diameter of the intermediate elastic body 27 is the same as that of the elastic bodies 22 and 23.

[0080] In the fourth embodiment of the tube-moving robot 300, as shown in FIG14(a), when the tip body 21 of the tip posture maintenance unit 20 moves in the straight section 2a of the tube 2, a pair of elastic bodies 22, 23 and elastic body 27 respectively abut against the inner peripheral surface of the straight section 2a of the tube 2, thereby maintaining the direction of the tip body 21's axis O in a posture parallel to the extension direction of the straight section 2a of the tube 2, and moving inside the tube 2. As shown in FIG14(b), when the tip posture maintenance unit 20 advances and the tip body 21 moves from the straight section 2a of the tube 2 to the curved section 2b, the front elastic body 22 abuts against the inner peripheral surface of the curved section 2b of the tube 2, the tip body 21 rotates around point 24a, and begins to bend along the curved section 2b. Then, as shown in Figures 14(c) and 14(d), when the tip posture maintaining part 20 advances further, the intermediate elastic body 27 locks onto the inner surface of the inner circumference of the curved portion 2b of the tube 2, causing the tip body part 21 to rotate around point 24a. As shown in Figure 14(e), when the tip posture maintaining part 20 advances further and the front elastic body 22 passes through the curved portion 2b and reaches the straight portion 2a, the locking of the intermediate elastic body 27 onto the inner surface of the inner circumference of the curved portion 2b is released, the front elastic body 22 abuts against the inner circumference of the straight portion 2a of the tube 2 and the rear elastic body 23 abuts against the inner circumference of the curved portion 2b of the tube 2, thereby gradually restoring the tip posture maintaining part 20 to the posture along the straight portion 2a. Then, as shown in Figure 14(f), when the tip posture maintaining part 20 advances further and the elastic body 23 on the rear side reaches the straight part 2a, a pair of elastic bodies 22, 23 and elastic body 27 respectively abut against the inner circumferential surface of the straight part 2a of the tube 2, the tip posture maintaining part 20 maintains its axis O in a posture parallel to the extension direction of the straight part 2a of the tube 2, and moves inside the tube 2 at the same time.

[0081] Thus, in the fourth embodiment of the tube-mounted mobile robot 300, the tip posture maintaining section 20 is configured such that, in addition to the front elastic body 22 and the rear elastic body 23, it also has an intermediate elastic body 27 located between the front elastic body 22 and the rear elastic body 23. Therefore, the tip posture maintaining section 20 can pass through the curved portion 2b more smoothly. This allows the tube-mounted mobile robot 300 to pass through the curved portion 2b of the tube 2 more reliably.

[0082] In the fourth embodiment of the tube-moving robot 300, it is preferable that the front elastic body 22 and the rear elastic body 23 are configured to have the same hardness or softness, while the middle elastic body 27 is configured to be more elastically deformable than the front elastic body 22 and the rear elastic body 23. Therefore, as shown in Figures 14(c) and 14(d), when the middle elastic body 27 engages with the inner surface of the inner circumference of the curved portion 2b of the tube 2, it can cause rotation centered on point 24a of the tip body 21, and simultaneously ensure that the middle elastic body 27 reliably passes through the curved portion 2b, enabling the tube-moving robot 300 to more reliably pass through the curved portion 2b.

[0083] The present invention is not limited to the described embodiments, and various modifications can certainly be made without departing from its spirit.

[0084] For example, in the first embodiment, the tip body 21 of the tip posture maintaining part 20 is configured to have a protruding part 21b, but the protruding part 21b may not be provided.

[0085] 1: In-pipe mobile robot 2: pipe 2a: Straight line portion 2b: Curved section 2c: Step difference 10: Robot Body 11: Telescopic Unit 11a:Tubular part 12: Connecting parts 13:Piping 14: Control Department 15: Brush 20: Tip posture maintenance unit 21:Apex body part 21a: Trunk 21b: Highlighted parts 22: Elastomer 23: Elastomers 22a, 23a: peripheral ends 24: Virtual Sphere 24a: point 25: Camera 26:Lighting device 27: Elastomers 30: Angle-limiting joint 31: Universal joint 32: Stop section 33: Front fixing part 34: Rear fixing part 35: Front rotating shaft 36: Rear rotating shaft 40: Flexible connection part 50: Cover 51: Inner cylindrical body 52: Outer cylindrical body 53: Holding component 53a: Inclined surface 54: Holding member 54a: Inclined surface 60: Stop position changing device 61: Cylinder 61a: Rod 62: Connector 100: In-pipe mobile robot 200: In-pipe mobile robot 300: In-pipe mobile robot O: Axis

Claims

1. A pipe-mounted mobile robot, configured to include a robot body comprising at least three telescopic units, each telescopic unit expanding radially and contracting axially upon fluid supply, the telescopic units performing peristaltic motion in a predetermined pattern, thereby enabling the pipe-mounted mobile robot to move within a pipe, the pipe-mounted mobile robot characterized by having: a tip posture maintaining portion having: a tip body portion constituting the tip of the pipe-mounted mobile robot; and a pair of elastic bodies, each elastic body being a generally annular or polygonal ring centered on the axis of the tip body portion, protruding radially outward from the outer peripheral surface of the tip body portion, and spaced apart from each other axially; an elastic connecting portion disposed between the tip posture maintaining portion and the robot body and capable of elastic deformation; and an angle limiting joint portion disposed between the elastic connecting portion and the robot body, allowing the tip posture maintaining portion to bend relative to the robot body at an angle of less than 90 degrees.

2. A pipe-mounted mobile robot, configured to include a robot body comprising at least three telescopic units, each telescopic unit expanding radially and contracting axially upon fluid supply, the telescopic units performing peristaltic motion in a predetermined pattern, thereby enabling the pipe-mounted mobile robot to move within a pipe, the pipe-mounted mobile robot characterized by having: a tip posture maintaining portion having: a tip body portion constituting the tip of the pipe-mounted mobile robot; and a pair of elastic bodies, each elastic body being a generally annular or polygonal ring centered on the axis of the tip body portion, protruding radially outward from the outer peripheral surface of the tip body portion, and spaced apart from each other axially; and an elastic connecting portion disposed between the tip posture maintaining portion and the robot body and capable of elastic deformation, the tip body portion having a protruding portion protruding forward from the pair of elastic bodies, the protruding portion retracting within a virtual sphere inscribed in the entire circumference by the outer peripheral ends of each of the pair of elastic bodies.

3. A pipe-mounted mobile robot, configured to include a robot body comprising at least three telescopic units, each telescopic unit expanding radially and contracting axially upon fluid supply, the telescopic units performing peristaltic motion in a predetermined pattern, thereby enabling the pipe-mounted mobile robot to move within a pipe, the pipe-mounted mobile robot characterized by having: a tip posture maintaining portion having: a tip body portion constituting the tip of the pipe-mounted mobile robot; and a pair of elastic bodies, each elastic body being a generally circular or polygonal ring centered on the axis of the tip body portion, protruding radially outward from the outer peripheral surface of the tip body portion, and spaced apart from each other axially; and an elastic connecting portion disposed between the tip posture maintaining portion and the robot body and capable of elastic deformation, the rear elastic body being more flexible than the front elastic body.

4. The in-tube mobile robot as described in any one of claims 1 to 3, wherein, The tip body portion has a protruding portion that protrudes forward from the pair of elastomers, and a camera is disposed on the axis of the protruding portion.

5. The in-pipe mobile robot as described in claim 1, wherein, The device has a cover comprising: an inner cylindrical body that is elastic and formed into a cylindrical shape; and an outer cylindrical body that is elastic and formed into a cylindrical shape, overlapping and disposed on the outside of the inner cylindrical body, wherein the frictional resistance generated between the inner cylindrical body and the outer cylindrical body is less than the frictional resistance generated between the outer cylindrical body and the inner surface of the tube, and the cover covers the angle-limiting joint.

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