A terahertz-based automatic scanning device for the outer surface of a circular cross-section object and application thereof

Abstract

The application discloses a kind of based on terahertz section as circular object outer surface automatic scanning device and its application, belong to terahertz technical field.It includes terahertz probe, annular moving mechanism, clamping structure and walking mechanism, annular moving mechanism drives terahertz probe to rotate around section as circular object periphery, clamping mechanism is used to clamp section as circular object, so that it is in annular moving mechanism central axis, walking mechanism drives terahertz probe, annular moving mechanism and clamping structure walk along section as circular object length direction.It can be used for the measurement of cable moisture content, to judge whether cable contains water, to realize the detection of cable water leakage point.The whole device can realize the perpendicular incidence of terahertz wave to section as circular object surface.Annular moving mechanism is detachable structure, convenient for the detection of two ends fixed section as circular object surface any point.

Description

Technical Field

[0001] This invention belongs to the field of terahertz technology, specifically relating to an automatic scanning device for the outer surface of a circular object based on terahertz and its application. Technical Background

[0002] Terahertz waves are electromagnetic waves with frequencies between 0.1 and 10 THz (corresponding to wavelengths of 30 μm to 3 mm). Terahertz time-domain spectroscopy can detect subtle differences in the structure of matter, strongly responding to low-frequency vibrations and resonances in crystal lattices. It also shows a strong response to weak interactions such as dipole rotation, hydrogen bonding, vibrational transitions, and van der Waals forces between organic molecules. It can sensitively detect changes in isomers and enantiomers, and is increasingly developing into an in-situ, non-invasive, and automated detection technology. It can be used for rapid detection of substances such as drugs, hazardous chemicals, explosives, and biomolecules, and has enormous application potential and demand in the field of automated detection.

[0003] When terahertz waves are used for sample detection, they need to be emitted perpendicularly to the sample surface. Existing equipment generally fixes the sample on a two-dimensional scanning platform, which moves the sample along the X and Y perpendicular directions to scan planar samples. However, it is difficult to scan curved surfaces, especially cylindrical samples. The challenge lies in ensuring that the wave emitted by the scanning device is perpendicularly incident on the surface of a cylindrical sample. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic scanning device for the outer surface of a cylindrical object based on terahertz and its application. It solves the problem of the terahertz probe fixing ring being coaxially set with the object with a circular cross-section, the problem of the scanning device automatically moving relative to the object with a circular cross-section, and the problem of finding water seepage points caused by cable surface damage.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] An automatic scanning device for the outer surface of a cylindrical object based on terahertz frequency.

[0007] The present invention relates to an automatic scanning device for a circular cross-section outer surface based on terahertz, comprising a terahertz probe and a ring moving mechanism. The ring moving mechanism drives the terahertz probe to rotate around the outer circumference of a circular cross-section object, wherein the circular cross-section object is a cable. The automatic scanning device is used to measure the moisture content of the cable. The terahertz probe emits terahertz waves perpendicularly to the surface of the cable, and determines whether the cable contains water based on the emitted signal, thereby realizing the detection of water leakage points in the cable.

[0008] This invention relates to an automatic scanning device for a circular cross-section surface based on terahertz, comprising a terahertz probe and a ring-shaped moving mechanism. The ring-shaped moving mechanism drives the terahertz probe to rotate around the outer circumference of a circular cross-section object. The ring-shaped moving mechanism includes a gear, a gear guide disk, a motor, a motor gear, a fixed plate, and guide wheels. The cross-section to be measured of the circular object, the ring-shaped gear, and the ring-shaped gear guide disk are coaxially arranged. The gear is mounted on the front surface of the gear guide disk. The motor and the terahertz probe are mounted on the front surface of the fixed plate. The output shaft of the motor is connected to the motor gear, and the motor gear meshes with the gear. At least two guide wheels are symmetrically mounted on the rear surface of the fixed plate via wheel axles on both the upper and lower sides. The fixed plate is in contact with the front surface of the gear. The upper guide wheel travels along the outer circumference of the rear side of the gear guide disk, and the lower guide wheel travels along the inner circumference of the rear side of the gear guide disk. The guide wheels limit the movement of the fixed plate.

[0009] Specifically, the annular moving mechanism also includes a ring, which is coaxially arranged with the gear guide disk. The ring is installed on the rear surface of the gear guide disk. The outer diameter of the ring is smaller than the outer diameter of the gear guide disk, and an outer guide groove is formed on the outer circumference of the ring. The inner diameter of the ring is larger than the inner diameter of the gear guide disk, and an inner guide groove is formed on the inner circumference of the ring. The guide wheels on the upper and lower parts of the fixed plate travel along the outer guide groove and the inner guide groove, respectively.

[0010] The gear is divided into an upper gear part and a lower gear part. Correspondingly, the gear guide disk is divided into an upper gear guide disk part and a lower gear guide disk part. The upper gear part is fixed to the upper gear guide disk part to form an upper independent unit, and the lower gear part is fixed to the lower gear guide disk part to form a lower independent unit. The upper gear part and the upper gear guide disk part have different corresponding arcs, and the lower gear part and the lower gear guide disk part have different corresponding arcs. The upper independent unit and the lower independent unit form a gear mounting part and a gear guide disk mounting part. In use, the two ends of the upper gear part are aligned with the two ends of the lower gear part, and the two ends of the upper gear guide disk part are aligned with the two ends of the lower gear guide disk part. The gear mounting part is installed on the gear guide disk mounting part.

[0011] The present invention relates to an automatic scanning device for a circular outer surface based on terahertz, and further includes a clamping structure. The clamping mechanism is used to clamp a circular object and position it on the central axis of a gear.

[0012] In one implementation, the clamping mechanism of the present invention includes a clamping jaw fixing part, a telescopic connecting rod, a clamping jaw motor, and clamping jaws. A clamping jaw is respectively provided on the left and right sides of an object with a circular cross-section. When the left and right clamping jaws clamp an object with a circular cross-section, the inscribed cylinder formed between the two clamping jaws is coaxial with the gear. The left and right clamping jaws are respectively connected to one end of a telescopic connecting rod. The other end of the telescopic connecting rod passes through a through hole on the clamping jaw fixing part and is connected to the output shaft of the clamping jaw motor. The clamping jaw fixing part is fixed on the rear surface of the gear guide plate.

[0013] The present invention relates to an automatic scanning device for a circular outer surface based on terahertz current, and further includes a traveling mechanism. The traveling mechanism comprises a first fixed block, a second fixed block, a lead screw motor, a lead screw, and guide rods. The output shaft of the lead screw motor is connected to one end of the lead screw, and the other end of the lead screw passes through threaded holes on the first and second fixed blocks. At least one guide rod, parallel to the lead screw, passes through through holes on the first and second fixed blocks. The first and second fixed blocks are slidable along the guide rods. The gripper fixing part has a semi-circular structure. The first fixed block is connected to the upper center of the gripper fixing part of the first clamping mechanism, and the second fixed block is connected to the upper center of the gripper fixing part of the second clamping mechanism. The first clamping mechanism is located on the left and right sides. The gripper motors on both sides drive the left and right grippers to move towards the circular object via corresponding telescopic links, clamping the circular object. Then, the gripper motors on both sides of the second clamping mechanism drive the left and right grippers away from the circular object via corresponding telescopic links, releasing the circular object. The lead screw motor drives the lead screw to rotate, causing the second fixed block to move towards the first fixed block. Then, the left and right grippers of the first clamping mechanism release the circular object, and the left and right grippers of the second clamping mechanism clamp the circular object. The lead screw motor drives the lead screw to rotate again, causing the first fixed block to move away from the second fixed block, thus realizing the movement of the entire scanning device relative to the circular object.

[0014] The clamping mechanism of the present invention further includes guide rollers, roller fixing plates, springs, spring support blocks, and spring fixing blocks. The grippers are V-shaped curved plates with guide grooves symmetrically opened on the upper and lower sides of the grippers. A roller fixing plate is fixed on the grippers above and below the guide grooves. A guide hole is opened on the roller fixing plate. The spring fixing block is fixed on the roller fixing plate on the side of the guide hole away from the circular cross-section of the object. The guide roller, which is partially embedded in the guide groove, is placed between the upper and lower roller fixing plates. The two ends of the guide roller axle are respectively connected to a spring support block. One end of the spring is fixed on the spring support block, and the other end is connected to the spring fixing block.

[0015] If the object with a circular cross-section bends vertically relative to the scanning device, the end of the telescopic link is hinged to the gripper. If the object with a circular cross-section bends horizontally relative to the scanning device, the first fixing block is hinged to the upper center of the gripper fixing part of the first clamping mechanism, and the second fixing block is hinged to the upper center of the gripper fixing part of the second clamping mechanism.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The terahertz probe is driven to rotate around the outer periphery of the object with a circular cross-section by the ring moving mechanism, so as to realize the perpendicular incidence of the terahertz wave on the surface of the object with a circular cross-section. The ring moving mechanism has a simple structure and is easy to operate; (2) The gear and the gear guide disk are detachably connected, which makes it easy to realize the detection of any point on the surface of the object with a circular cross-section (especially the object with a circular cross-section whose two ends are fixed and cannot be directly inserted into the middle of the gear guide disk) under special environments; (3) The cooperation between the walking mechanism and the double clamping mechanism makes it easy for the scanning device to automatically walk along the outer length direction of the object with a circular cross-section; (4) The setting of the guide roller related structure ensures that the gripper ensures that the scanning device does not deviate when walking; (5) The end of the telescopic link is hinged to the gripper, so that the gripper can rotate around the telescopic link, which is convenient for clamping objects that are bent in the vertical direction. The first fixed block is hinged to the upper center position of the gripper fixing part of the first clamping mechanism, and the second fixed block is hinged to the upper center position of the gripper fixing part of the second clamping mechanism, so that the gripper fixing part can rotate around the fixed block, which is convenient for clamping objects that are bent in the horizontal direction. (6) The symmetrical clamping of the dual clamping mechanism can achieve self-centering function, which can ensure that the axis of the object with a circular cross-section is coincident with the axis of the ring motion mechanism, ensuring that the terahertz probe is perpendicularly incident on the object with a circular cross-section when scanning at any position. (7) The jaws are V-shaped curved plates, which can be adapted to clamp objects with circular cross-sections of different diameters. They are highly adaptable and do not need to be replaced when measuring objects with circular cross-sections of different sizes. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the automatic scanning device with a circular outer surface based on terahertz in Example 1.

[0018] Figure 2 for Figure 1 The main view.

[0019] Figure 3 for Figure 1 Rear view.

[0020] Figure 4 for Figure 1 The right view.

[0021] Figure 5 Rear view of the assembly structure of the motor, motor gear, mounting plate and guide wheel.

[0022] Figure 6 This is a structural diagram of a gear and gear guide plate that can be separated into upper and lower parts.

[0023] Figure 7 This is a diagram showing the state of a tubular sample held by grippers.

[0024] Figure 8 for Figure 7 Top view.

[0025] Figure 9 This is a diagram showing the state when the grippers are not holding the tubular sample.

[0026] Figure 10 for Figure 9 Top view.

[0027] Figure 11 This is a diagram showing the clamping state of the automatic scanning device structure when a tubular sample is bent vertically.

[0028] Figure 12 This is a diagram showing the clamping state of the automatic scanning device structure when a tubular sample is bent to the left or right.

[0029] Among them, 1 is a scanning device, 2 is a ring-shaped moving mechanism, 3 is a circular object, 4 is a clamping mechanism, 5 is a walking mechanism, 201 is a gear, 202 is a gear guide plate, 203 is a motor, 204 is a motor gear, 205 is a fixing plate, 206 is a guide wheel, 207 is a ring, 401 is a gripper fixing part, 402 is a telescopic connecting rod, 403 is a gripper motor, 404 is a gripper, 405 is a guide roller, 406 is a roller fixing plate, 407 is a spring, 408 is a spring support block, 409 is a spring fixing block, 501 is a first fixing block, 502 is a second fixing block, 503 is a lead screw motor, 504 is a lead screw, and 505 is a guide rod. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] The terms "first," "second," etc., used in this invention are merely for distinguishing components and do not constitute a limitation on the scope of protection. The directional terms such as "left," "right," "front," and "rear" are for describing the relative positions between components and do not constitute a limitation on the scope of protection.

[0032] Example 1

[0033] like Figure 1-5As shown, this embodiment relates to an automatic scanning device for a circular cross-section surface based on terahertz current. It includes a terahertz probe 1 and a ring-shaped moving mechanism 2. The ring-shaped moving mechanism 2 drives the terahertz probe 1 to rotate around the outer circumference of a circular object 3. The ring-shaped moving mechanism includes a gear 201, a gear guide disk 202, a motor 203, a motor gear 204, a fixing plate 205, and a guide wheel 206. The circular object 3, the ring-shaped gear 201, and the ring-shaped gear guide disk 202 are coaxially arranged. The gear 201 is mounted on the front surface of the gear guide disk 202. The motor 203 and the terahertz probe 1 are mounted on... On the front surface of the fixed plate 205, the output shaft of the motor 203 is connected to the motor gear 204, which meshes with the gear. At least two guide wheels 206 are symmetrically installed on the rear surface of the fixed plate 205 via axles. The fixed plate 205 contacts the front surface of the gear 201. The upper guide wheel 206 travels along the outer circumference of the rear side of the gear guide disk 202, and the lower guide wheel 206 travels along the inner circumference of the rear side of the gear guide disk 202. That is, the gear 201 and the gear guide disk 202 are embedded between the fixed plate 205 and the upper and lower guide wheels 206, and the guide wheels 206 limit the fixed plate 205. Driven by the motor, the motor gear 204 rotates around the gear, thereby driving the terahertz probe 1 to rotate around the gear 201. During this process, the terahertz probe 1 emits terahertz waves perpendicularly to the circumferential surface (outer surface) of the circular object 3.

[0034] Specifically, the gear is an external gear, and the motor gear 204 meshes with the external gear, such as... Figure 1 As shown. Of course, the gear can also be an internal gear, with the motor gear 204 meshing with the internal gear.

[0035] Specifically, the annular moving mechanism 2 also includes a ring 207, which is coaxially arranged with the gear guide disk 202. The ring 207 is mounted on the rear surface of the gear guide disk 202. The outer diameter of the ring 207 is smaller than the outer diameter of the gear guide disk 202, forming an outer guide groove on the outer circumference of the ring 207. The inner diameter of the ring 207 is larger than the inner diameter of the gear guide disk 202, forming an inner guide groove on the inner circumference of the ring 207. The guide wheels on the upper and lower parts of the fixed plate travel along the outer guide groove and the inner guide groove, respectively. The ring 207 and the gear guide disk 202 can be an integral structure or a separate design.

[0036] In the actual generation process, the cross-section of the circular object 3 is relatively long. To facilitate scanning any point on the surface of the circular object and to quickly and easily fix the terahertz probe 1 to the upper part of that point, the gear 201 is divided into an upper gear 2011 and a lower gear 2012. Correspondingly, the gear guide disk 202 is divided into an upper gear guide disk 2021 and a lower gear guide disk 2022. The upper gear 2011 is fixed to the upper gear guide disk 2021 to form an independent upper unit, and the lower gear 2012 is fixed to the lower gear guide disk 2022 to form a lower unit. The upper and lower independent units have different curvatures corresponding to the upper gear 2011 and the upper gear guide disk 2021, and the lower gear 2012 and the lower gear guide disk 2022. The upper and lower independent units form a gear mounting part 2013 and a gear guide disk mounting part 2014. In use, the two ends of the upper gear 2011 are aligned with the two ends of the lower gear 2012, the two ends of the upper gear guide disk 2021 are aligned with the two ends of the lower gear guide disk 202, and the gear mounting part 2013 is mounted on the gear guide disk mounting part 2014.

[0037] This embodiment relates to an automatic scanning device for a circular outer surface based on terahertz, which also includes a clamping structure. The clamping mechanism is used to clamp a circular object 3 and place it on the central axis of the gear.

[0038] As one implementation, the clamping mechanism 4 involved in this embodiment includes a jaw fixing part 401, a telescopic connecting rod 402, a jaw motor 403, and jaws 404. A jaw 404 is respectively arranged on the left and right sides of the circular object 3. When the two jaws 404 clamp the circular object 3, the inscribed cylinder formed between the two jaws 404 is coaxial with the gear 201. The two jaws 404 are respectively connected to one end of a telescopic connecting rod 402. The other end of the telescopic connecting rod 402 passes through a through hole in the jaw fixing part 401 and is connected to the output shaft of the jaw motor 403. The jaw fixing part 401 is fixed to the rear surface of the gear guide plate 202. Under the drive of the jaw motor 403, the jaws 404 on both sides move closer to the circular object 3, clamping the circular object 3; when the jaws 404 move away from the circular object 3, they release the circular object 3.

[0039] This embodiment involves a terahertz-based automatic scanning device for a circular outer surface, which further includes a traveling mechanism 5. The traveling mechanism 5 includes a first fixed block 501, a second fixed block 502, a lead screw motor 503, a lead screw 504, and a guide rod 505. The output shaft of the lead screw motor 503 is connected to one end of the lead screw 504, and the other end of the lead screw 504 passes through threaded holes on the first fixed block 501 and the second fixed block 502. At least one guide rod 505, parallel to the lead screw 504, passes through through holes on the first fixed block 501 and the second fixed block 502. The first fixed block 501 and the second fixed block 502 can slide along the guide rod 505. The gripper fixing part 401 has a semi-circular structure. The first fixed block 501 is connected to the upper center of the gripper fixing part 401 of the first gripping mechanism, and the second fixed block 502 is connected to the upper center of the gripper fixing part 401 of the second gripping mechanism.

[0040] The gripper motors 403 on the left and right sides of the first gripping mechanism drive the left and right grippers 404 to move towards the circular object 3 via corresponding telescopic connecting rods 402, clamping the circular object 3. The gripper motors 403 on the left and right sides of the second gripping mechanism drive the left and right grippers 404 to move away from the circular object 3, releasing it. The lead screw motor 503 drives the lead screw to rotate, causing the second fixing block 502 to move towards the first fixing block 501. Then, the left and right grippers 404 of the first gripping mechanism release the circular object 3, and the left and right grippers 404 of the second gripping mechanism clamp the circular object 3. The lead screw motor 503 drives the lead screw to rotate again, causing the first fixing block 501 to move away from the second fixing block 502, thus realizing the movement of the entire scanning device relative to the circular object 3. The guide rod 505 in the walking mechanism restricts the degrees of freedom of movement of the first and second gripping mechanisms, preventing them from falling.

[0041] like Figure 7-10As shown, the clamping mechanism involved in this embodiment also includes a guide roller 405, a roller fixing plate 406, a spring 407, a spring support block 408, and a spring fixing block 409. The gripper 404 is a V-shaped curved plate. A guide groove 410 is symmetrically opened on the upper and lower sides of the gripper 404. A roller fixing plate 406 is fixed on the gripper 404 above and below the guide groove 410. A guide hole 411 is opened on the roller fixing plate 406. The spring fixing block 409 is fixed on the roller fixing plate 406 on the side away from the circular object 3 with the guide hole 411. The guide roller 405, which is partially embedded in the guide groove 410, is placed between the upper and lower roller fixing plates 406. The two ends of the axle of the guide roller 405 are respectively connected to a spring support block 408. One end of the spring 407 is fixed on the spring support block 408, and the other end is connected to the spring fixing block 409. This structure uses a spring 407 to maintain a preload on the guide roller 405 in the direction of the circular object 3. Even when the grippers are open, the guide roller 405 remains in close contact with the outer surface of the circular object 3, ensuring that the scanning device moves in the correct direction without deviation. When the grippers are clamped, the guide roller is inactive. When the grippers are open, the lead screw drives the grippers to move, and the guide roller remains in close contact with the outer surface of the circular object 3 (such as a cable), allowing the grippers to move in the direction of the guide roller's rolling motion, ensuring that the scanning device moves without deviation.

[0042] In this embodiment, the circular cross-section object 3 can be a rigid material such as a steel pipe, or a flexible material such as a cable. Flexible materials can be bent. If the cable bends vertically relative to the scanning device, the end of the telescopic link is hinged to the gripper 404, allowing the gripper 404 to rotate around the telescopic link 402. Figure 11 Rotation direction (vertical rotation). If the cable bends to the left or right relative to the scanning device, the first fixing block 501 is hinged to the upper center of the gripper fixing part 401 of the first clamping mechanism, and the second fixing block 502 is hinged to the upper center of the gripper fixing part 401 of the second clamping mechanism, so that the gripper fixing part 401 can rotate around the fixing block. Figure 12 Rotation (rotation in the horizontal direction).

[0043] This embodiment relates to a terahertz-based automatic scanning device for circular outer surfaces, used for performing life analysis such as material analysis, substance analysis, and aging degree analysis on circular objects 3. Circular objects 3 include, but are not limited to, cables, non-metallic pipes, and optical cables.

[0044] The outer surface of buried cables may be damaged, allowing moisture to seep in. Existing technologies lack specific methods for detecting cable leaks. The device described in this embodiment can detect the cable's moisture content, accurately locate leaks, and its easily disassembled and installed gear 201 and gear guide plate 202 facilitate detection at any point on the cable in use. Simultaneously, the traveling mechanism can automatically scan cables of any length.

[0045] Terahertz waves have the characteristic that they produce different reflected signals when passing through different media due to differences in refractive index. For example, because air and cables have different refractive indices, terahertz waves will produce a reflected signal when entering the interior of a cable from air; terahertz waves are absorbed by water and will not produce a reflected signal; if they come into contact with the metal layer of the cable, they cannot penetrate, and the returned signal at this location is the farthest distance signal. The depth of the reflection location can be determined based on the different return times of the reflected signals.

[0046] Because our motion mechanism ensures that the terahertz probe is perpendicular to the cylindrical surface during detection, the reflected signal will return to the terahertz probe along the original path, thus ensuring the accuracy of the received signal strength and the detection position.

[0047] Based on this characteristic, after a terahertz probe sends terahertz waves to the surface of a cylindrical object, the waves will be reflected depending on the material. If the terahertz waves are absorbed by water before reaching the metal layer, it will result in a signal void.

[0048] After different signals are reflected, based on the different return times, the material properties of the cylinder can be reconstructed by the algorithm to display a one-dimensional image showing the radial direction of the cylinder. When our equipment is running in a spiral in the axial and circumferential directions, it can form a two-dimensional image of the side of the cylinder based on the feedback from the position and distance sensor. This image and the radial material property image of the cylinder are reconstructed in three dimensions by the algorithm to form a three-dimensional reconstruction model. This model can intuitively display the actual position and size of the water inside the cylindrical object.

[0049] Therefore, the aforementioned terahertz-based automatic scanning device for circular outer surfaces is used to measure the moisture content of cables. It can accurately detect the location of cable leaks and can be conveniently used on-site.

Claims

1. An automatic scanning device for a circular outer surface based on terahertz current, characterized in that, It includes a terahertz probe, a ring-shaped moving mechanism, a clamping structure, and a walking mechanism. The ring-shaped moving mechanism drives the terahertz probe to rotate around the outer periphery of an object with a circular cross-section. The clamping mechanism is used to clamp the object with a circular cross-section and place it on the central axis of the gear. The clamping mechanism includes a clamping jaw fixing part, a telescopic connecting rod, a clamping jaw motor, and clamping jaws. A clamping jaw is provided on the left and right sides of an object with a circular cross-section. When the two clamping jaws clamp an object with a circular cross-section, the inscribed cylinder formed between the two clamping jaws is coaxial with the gear. The two clamping jaws are respectively connected to one end of a telescopic connecting rod. The other end of the telescopic connecting rod passes through the through hole on the clamping jaw fixing part and is connected to the output shaft of the clamping jaw motor. The clamping jaw fixing part is fixed on the rear surface of the gear guide plate. The traveling mechanism includes a first fixed block, a second fixed block, a lead screw motor, a lead screw, and guide rods. The output shaft of the lead screw motor is connected to one end of the lead screw, and the other end of the lead screw passes through threaded holes on the first and second fixed blocks. At least one guide rod, parallel to the lead screw, passes through through holes on the first and second fixed blocks, allowing the first and second fixed blocks to slide along the guide rods. The gripper fixing part has a semi-circular structure. The first fixed block is connected to the upper center of the gripper fixing part of the first clamping mechanism, and the second fixed block is connected to the upper center of the gripper fixing part of the second clamping mechanism. The gripper motors on the left and right sides of the first clamping mechanism are connected via corresponding telescopic connecting rods. The first clamping mechanism moves the left and right grippers toward the circular object, clamping it. Then, the gripper motors on both sides of the second clamping mechanism, via corresponding telescopic links, move the left and right grippers away from the circular object, releasing it. The lead screw motor rotates the lead screw, causing the second fixed block to move toward the first fixed block. Then, the left and right grippers of the first clamping mechanism release the circular object, and the left and right grippers of the second clamping mechanism clamp the circular object. The lead screw motor rotates the lead screw again, causing the first fixed block to move away from the second fixed block, thus realizing the movement of the entire scanning device relative to the circular object.

2. The terahertz-based automatic scanning device for a circular outer surface as described in claim 1, characterized in that, The annular moving mechanism includes a gear, a gear guide disk, a motor, a motor gear, a fixed plate, and guide wheels. The cross-section of the object to be measured is a circular object. The annular gear and the annular gear guide disk are coaxially arranged. The gear is mounted on the front surface of the gear guide disk. The motor and the terahertz probe are mounted on the front surface of the fixed plate. The output shaft of the motor is connected to the motor gear, and the motor gear meshes with the gear. At least two guide wheels are symmetrically mounted on the rear surface of the fixed plate through wheel axles on both the top and bottom. The fixed plate is in contact with the front surface of the gear. The upper guide wheel travels along the outer circumference of the rear side of the gear guide disk, and the lower guide wheel travels along the inner circumference of the rear side of the gear guide disk. The guide wheels limit the movement of the fixed plate.

3. The terahertz-based automatic scanning device for a circular outer surface as described in claim 2, characterized in that, The annular moving mechanism also includes a ring, which is coaxially arranged with the gear guide disk. The ring is installed on the rear surface of the gear guide disk. The outer diameter of the ring is smaller than the outer diameter of the gear guide disk, and an outer guide groove is formed on the outer circumference of the ring. The inner diameter of the ring is larger than the inner diameter of the gear guide disk, and an inner guide groove is formed on the inner circumference of the ring. The guide wheels on the upper and lower parts of the fixed plate travel along the outer guide groove and the inner guide groove, respectively.

4. The terahertz-based automatic scanning device for a circular outer surface as described in claim 2, characterized in that, The gear is divided into an upper gear part and a lower gear part. Correspondingly, the gear guide disk is divided into an upper gear guide disk part and a lower gear guide disk part. The upper gear part is fixed to the upper gear guide disk part to form an upper independent unit, and the lower gear part is fixed to the lower gear guide disk part to form a lower independent unit. The upper gear part and the upper gear guide disk part have different corresponding arcs, and the lower gear part and the lower gear guide disk part have different corresponding arcs. The upper independent unit and the lower independent unit form a gear mounting part and a gear guide disk mounting part. In use, the two ends of the upper gear part are aligned with the two ends of the lower gear part, and the two ends of the upper gear guide disk part are aligned with the two ends of the lower gear guide disk part. The gear mounting part is installed on the gear guide disk mounting part.

5. The terahertz-based automatic scanning device for a circular outer surface as described in claim 1, characterized in that, The clamping mechanism also includes guide rollers, roller fixing plates, springs, spring support blocks, and spring fixing blocks. The grippers are V-shaped curved plates with symmetrical guide grooves on the upper and lower sides. A roller fixing plate is fixed on each of the grippers above and below the guide grooves. A guide hole is opened on the roller fixing plate. The spring fixing block is fixed on the roller fixing plate on the side of the guide hole away from the circular cross-section of the object. The guide roller, which is partially embedded in the guide groove, is placed between the upper and lower roller fixing plates. The two ends of the guide roller's axle are respectively connected to a spring support block. One end of the spring is fixed on the spring support block, and the other end is connected to the spring fixing block.

6. The terahertz-based automatic scanning device for a circular outer surface according to claim 5, characterized in that, If the object with a circular cross-section bends vertically relative to the scanning device, the end of the telescopic link is hinged to the gripper. If the object with a circular cross-section bends horizontally relative to the scanning device, the first fixing block is hinged to the upper center of the gripper fixing part of the first clamping mechanism, and the second fixing block is hinged to the upper center of the gripper fixing part of the second clamping mechanism.

7. The application of the terahertz-based automatic scanning device with a circular cross-section for measuring the moisture content of cables as described in claim 1, wherein the circular cross-section object is a cable, the automatic scanning device is used to measure the moisture content of the cable, the terahertz probe emits terahertz waves perpendicularly to the surface of the cable, and the cable is judged to contain water based on the transmitted signal, thereby realizing the detection of water leakage points in the cable.

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