An adaptive flexible wall-attached mechanism for shield tunnel radar monitoring

Abstract

The utility model relates to underground engineering nondestructive testing technical field, concretely relates to a kind of self-adapting flexible wall-sticking mechanism for shield tunnel radar monitoring, including main installation support and radar carrying bottom plate, the bottom of main installation support is fixedly provided with upper connecting crossbeam, and two lateral swing guide slide rods are assembled in upper connecting crossbeam;The self-adapting flexible wall-sticking mechanism for shield tunnel radar monitoring is kept by adaptive four-bar linkage swing structure, lateral direction guiding limiting block and lateral spring buffer assembly, and is coordinated with universal ball hinge mechanism, realizes follow-up wall-sticking, avoids the wedge-shaped air gap formed between antenna end face and wall surface, ensures that radar beam is incident with normal angle, to improve electromagnetic transmission efficiency and echo signal-to-noise ratio, and enhance the detection ability of small defect;Universal ball hinge mechanism with pre-tightening damping elastomer is used in cooperation with guide slide rod and lateral spring buffer assembly, adaptive absorption double curvature change and segment misalignment, ensure antenna smooth sliding.

Description

Technical Field

[0001] This utility model relates to the field of non-destructive testing technology for underground engineering, specifically to an adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels. Background Technology

[0002] During long-term operation, shield tunnels are affected by ground stress, groundwater erosion, and vibration loads, which can easily cause defects in the lining such as segment cracking, water leakage, and internal voids. If these defects are not diagnosed in time, they may endanger the safety of the tunnel structure.

[0003] Ground penetrating radar (GPR) has become a core tool for detecting defects inside tunnel linings due to its non-destructive nature, high resolution, and sensitivity to differences in dielectric constant.

[0004] Traditional inspection methods mainly rely on manual handheld inspection and vehicle-mounted platforms. However, manual handheld inspection is inefficient and labor-intensive, and requires lifting equipment when inspecting arches, posing significant safety hazards. While vehicle-mounted platforms improve data acquisition speed, they require closed lanes, and radar antennas are usually rigidly fixed to the vehicle body via robotic arms. The vibrations caused by vehicle movement lead to fluctuations in the distance between the antenna and the wall, and the unstable air coupling reduces the electromagnetic wave energy transmittance, severely affecting the accuracy of deep defect detection.

[0005] In recent years, the use of automated wall-climbing robots equipped with inspection equipment for autonomous tunnel inspection has become a development trend. However, when wall-climbing robots are equipped with ground-penetrating radar for dynamic inspection, they face the technical challenge of ensuring that the antenna maintains normal contact and a constant coupling distance with the surface being measured under robot movement and complex tunnel wall conditions.

[0006] Existing radar mounting mechanisms mostly employ rigid connections or single-dimensional spring supports. However, rigid connections cannot absorb the impact of segment misalignment, easily leading to damage to the radar antenna or loss of adhesion for the robot under reaction force. On the other hand, with single-dimensional spring supports, when the robot tilts, the antenna's bottom surface cannot follow the wall curvature change, resulting in a wedge-shaped air gap between the antenna end face and the wall surface. This causes the radar wave incident angle to deviate from the normal, altering the signal delay reference and affecting offset imaging processing, leading to errors in subsequent defect identification.

[0007] Therefore, there is an urgent need in the field for a flexible wall-adhering mechanism that can adapt to complex three-dimensional topography, maintain radar beam normal injection, stabilize coupling gap, and take into account obstacle avoidance and buffering capabilities, so as to ensure the detection accuracy of ground penetrating radar without affecting the safe operation and obstacle-crossing performance of the wall-climbing robot. Utility Model Content

[0008] To achieve the above objectives, this utility model adopts the following technical solution: It provides an adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels. The mechanism maintains its attitude through an adaptive four-bar swing structure, a lateral guide limit block, and a lateral spring buffer assembly. In conjunction with a universal ball joint mechanism, it achieves wall-adhering motion, preventing the formation of a wedge-shaped air gap between the antenna end face and the wall surface, ensuring the radar beam is incident at a normal angle, thereby improving electromagnetic transmission efficiency and echo signal-to-noise ratio, and enhancing the detection capability of minute defects. The universal ball joint mechanism with a pre-tightened damping elastomer, in conjunction with the guide slide and the lateral spring buffer assembly, adaptively absorbs changes in hyperbola and segment misalignment, ensuring smooth antenna sliding.

[0009] To address the problems of existing technologies, this utility model provides an adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels, including a main mounting bracket and a radar mounting base plate. An upper connecting beam is fixedly installed at the bottom of the main mounting bracket, and the upper connecting beam is equipped with two laterally swingable guide rods. The bottom sides of the main mounting bracket extend downwards to form connecting portions, and lateral guide limiting blocks and lateral spring buffer assemblies are respectively installed on both sides of the connecting portions. The lateral guide limiting blocks are located at the ends of the lateral offset paths of the guide rods to limit the maximum lateral offset of the guide rods. The spring buffer assembly laterally engages with the guide slide rod; the radar mounting base plate is located directly below the main mounting bracket, and a universal ball joint mechanism is fixedly installed at the center of the top surface of the radar mounting base plate. The universal ball joint mechanism includes a fixed end and a rotating end that rotate with each other, and a lower connecting beam is fixedly assembled on the rotating end; the bottom of the two guide slide rods extends vertically and is hinged to the lower connecting beam. The upper connecting beam, the two guide slide rods, and the lower connecting beam together constitute an adaptive four-bar swing structure; roller assemblies for traveling along the tunnel wall are arranged at the bottom corners of the radar mounting base plate.

[0010] Preferably, the gap between the fixed end and the rotating end of the universal ball joint mechanism is filled with a pre-tightened damping elastomer; the pre-tightened damping elastomer is disposed in the ball joint gap, and its axial thickness or radial dimension determines the maximum swing angle of the rotating end of the ball joint relative to the fixed end.

[0011] Preferably, the lateral guide limiting block and the lateral spring buffer assembly are arranged perpendicularly or obliquely relative to the connecting part to adapt to the curved surface posture of the tunnel and achieve normal pre-tightening against the wall and vibration impact absorption.

[0012] Preferably, the upper and lower ends of the guide slide rod are respectively hinged to the upper connecting beam and the lower connecting beam via a pin structure with a self-lubricating bearing.

[0013] Preferably, the lateral spring buffer assembly includes: an outer sleeve, the tail end of which is hinged to the inner wall of the connection part of the main mounting bracket via a cross-shaped universal joint, and a fine-tuning nut is fitted at the open end of the outer sleeve; an inner slide rod, one end of which is coaxially slidably inserted into the interior of the outer sleeve, and the other end of which is hinged to the middle of the guide slide rod; a main compression helical spring, coaxially sleeved on the outside of the inner slide rod, with both ends of the main compression helical spring abutting against the fine-tuning nut and the limiting flange provided on the inner slide rod, respectively; and a viscous fluid damper, coaxially arranged with the main compression helical spring, the viscous fluid damper outputting a damping force positively correlated with the extension and contraction speed.

[0014] Preferably, the radar mounting base plate is made of a non-metallic wave-transparent material with low relative permittivity and low loss tangent, and the radar mounting base plate is filled with radar absorbing material to shield electromagnetic clutter from non-detection directions.

[0015] Preferably, the guide slide rod is a telescopic rod structure with adjustable length, and the main body of the guide slide rod adopts a positive and negative thread rod structure with a locking nut to realize length adjustment and positioning locking.

[0016] The advantages of this utility model compared to the prior art are:

[0017] 1. The attitude is maintained by an adaptive four-bar swing structure, a lateral guide limit block and a lateral spring buffer assembly, and works in conjunction with a universal ball joint mechanism to achieve follow-up wall contact, avoid the formation of a wedge-shaped air gap between the antenna end face and the wall surface, ensure that the radar beam is incident at the normal angle, thereby improving electromagnetic transmission efficiency and echo signal-to-noise ratio, and enhancing the ability to detect small defects.

[0018] 2. By utilizing a universal ball joint mechanism with a pre-tightened damping elastomer in conjunction with a guide slide and a lateral spring buffer assembly, the antenna can adaptively absorb changes in hyperbola and misalignment of the tube segments, ensuring smooth sliding. Attached Figure Description

[0019] Figure 1 This is a front-view three-dimensional structural diagram of an adaptive flexible wall-adhering mechanism used for radar monitoring of shield tunnels.

[0020] Figure 2 This is a bottom-view three-dimensional structural diagram of an adaptive flexible wall-adhering mechanism used for radar monitoring of shield tunnels.

[0021] Figure 3 This is a three-dimensional schematic diagram of a four-bar swing structure for an adaptive flexible wall-adhering mechanism used for radar monitoring of shield tunnels.

[0022] Figure 4 yes Figure 3 A magnified structural diagram at point A.

[0023] Figure 5 This is a three-dimensional cross-sectional diagram of a four-bar swing structure for an adaptive flexible wall-adhering mechanism used for radar monitoring of shield tunnels.

[0024] Figure 6 yes Figure 5 A magnified structural diagram at point B.

[0025] Figure 7 yes Figure 5 A magnified structural diagram at point C.

[0026] The following are the labels in the diagram: 1. Main mounting bracket; 1a. Upper connecting beam; 1b. Guide slide rod; 1c. Lateral guide limit block; 1d. Lateral spring buffer assembly; 1d1. Outer sleeve; 1d2. Inner slide rod; 1d3. Main compression helical spring; 1d4. Viscous fluid damper; 2. Radar mounting base plate; 2a. Universal ball joint mechanism; 2a1. Lower connecting beam; 2a2. Pre-tightened damping elastomer; 2b. Roller assembly. Detailed Implementation

[0027] To further understand the features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments.

[0028] See Figures 1 to 5 As shown, an adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels includes a main mounting bracket 1 and a radar mounting base plate 2. An upper connecting beam 1a is fixedly installed at the bottom of the main mounting bracket 1, and the upper connecting beam 1a is equipped with two laterally swinging guide rods 1b.

[0029] The main mounting bracket 1 extends downward on both sides of its bottom to form connecting parts. The connecting parts on both sides are respectively equipped with lateral guide limiting blocks 1c and lateral spring buffer assemblies 1d. The lateral guide limiting blocks 1c are located at the end of the lateral offset path of the guide slide rod 1b and are used to limit the maximum lateral offset of the guide slide rod 1b. The lateral spring buffer assembly 1d is laterally engaged with the guide slide rod 1b.

[0030] The aforementioned main mounting bracket 1 is fixedly mounted on the robot connection base. The main mounting bracket 1, the upper connecting beam 1a, and the guide slide rod 1b constitute a lateral limiting base.

[0031] See Figures 1 to 3 and Figure 5 As shown, the radar mounting base plate 2 is located directly below the main mounting bracket 1. A universal ball joint mechanism 2a is fixedly installed at the center of the top surface of the radar mounting base plate 2. The universal ball joint mechanism 2a includes a fixed end and a rotating end that rotate and cooperate with each other. A lower connecting crossbeam 2a1 is fixedly assembled on the rotating end.

[0032] Among them, the universal ball joint mechanism 2a is a partial hinge component of the base plate, which is responsible for the large-angle curved surface follow-up compensation of the main mounting bracket 1.

[0033] See Figure 3 and Figure 5 As shown, the bottom of the two guide slide rods 1b extends vertically and is hinged to the lower connecting beam 2a1. The upper connecting beam 1a, the two guide slide rods 1b, and the lower connecting beam 2a1 together constitute an adaptive four-bar swing structure.

[0034] The aforementioned four-link suspension, combined with the lateral spring buffer assembly 1d, forms a two-stage fine-tuning suspension.

[0035] When the wall surface undulation is small, the impact is mainly absorbed by the elastic deformation of the lateral spring buffer assembly 1d, and the angular compensation is performed by the universal ball joint mechanism 2a.

[0036] When the fluctuation exceeds the preset threshold, the guide slide bar 1b shifts laterally relative to the upper connecting beam 1a, causing the four-bar linkage to swing as a whole, thus achieving large-stroke floating.

[0037] See Figure 2 As shown, the bottom corner of the radar mounting base plate 2 is provided with roller assembly 2b for moving along the tunnel wall.

[0038] It should be noted that roller assembly 2b is a small auxiliary support roller for the base plate.

[0039] Roller assembly 2b is a follow-up ranging fine-tuning roller assembly, whose array is arranged on the bottom edge of the transparent radar protective housing to achieve real-time ranging control and ensure antenna fitting accuracy.

[0040] See Figure 7 As shown, the gap between the fixed end and the rotating end of the universal ball joint mechanism 2a is filled with a pre-tightened damping elastomer 2a2.

[0041] The pre-tightened damping elastomer 2a2 is disposed in the ball joint fit gap, and its axial thickness or radial dimension determines the maximum swing angle of the ball joint rotating end relative to the fixed end.

[0042] The pre-tightened damping elastomer 2a2 can eliminate the gap in the universal ball joint mechanism 2a, attenuate small vibrations, and adjust the external dimensions and limit angle.

[0043] See Figure 2 and Figure 3 As shown, the lateral guide limiting block 1c and the lateral spring buffer assembly 1d are arranged perpendicularly or obliquely relative to the connecting part to adapt to the curved surface posture of the tunnel and achieve normal pre-tightening to the wall and vibration impact absorption.

[0044] When in use, the lateral spring buffer assembly 1d provides lateral buffering force and can provide the main normal preload of the whole machine.

[0045] See Figure 3 and Figure 5 As shown, the upper and lower ends of the guide slide rod 1b are respectively hinged to the upper connecting beam 1a and the lower connecting beam 2a1 through a pin structure with a self-lubricating bearing.

[0046] It should be noted that the guide slide 1b hinge pin is equipped with a self-lubricating bearing to unify the hinge structure and reduce motion wear.

[0047] See Figures 4 to 6 As shown, the lateral spring buffer assembly 1d includes an outer sleeve 1d1, an inner slide bar 1d2, a main compression helical spring 1d3, and a viscous fluid damper 1d4.

[0048] The tail end of the outer sleeve 1d1 is hinged to the inner wall of the connecting part of the main mounting bracket 1 via a cross shaft universal joint, and the open end of the outer sleeve 1d1 is equipped with a fine-tuning nut.

[0049] One end of the inner slide rod 1d2 is slidably inserted into the outer sleeve 1d1, and the other end of the inner slide rod 1d2 is hinged to the middle of the guide slide rod 1b.

[0050] The main compression helical spring 1d3 is coaxially sleeved on the outside of the inner slide rod 1d2, and the two ends of the main compression helical spring 1d3 abut against the fine-adjusting nut and the limiting flange provided on the inner slide rod 1d2, respectively.

[0051] The viscous fluid damper 1d4 is arranged coaxially with the main compression helical spring 1d3, and the output of the viscous fluid damper 1d4 is a damping force that is positively correlated with the extension and contraction speed.

[0052] The aforementioned lateral spring buffer assembly 1d is a small lateral buffer unit, and the preload can be adjusted by using a fine-tuning nut.

[0053] See Figure 1 As shown, the radar mounting base plate 2 is made of a non-metallic wave-transparent material with low relative permittivity and low loss tangent, and the radar mounting base plate 2 is filled with radar absorbing material to shield electromagnetic clutter from non-detection directions.

[0054] Specifically, the radar mounting base plate 2 has an internal cavity, which is filled with radar absorbing material except for the wave-transmitting window. The wave-transmitting window is a cylindrical space in the cavity that is not filled with radar absorbing material. The lower end of the wave-transmitting window is connected to the bottom detection area of ​​the radar mounting base plate 2, and the upper end extends to the top of the cavity to allow the radar beam to be transmitted downwards. The remaining internal cavities of the radar mounting base plate 2 are filled with radar absorbing material to absorb and shield electromagnetic clutter from non-detection directions.

[0055] See Figure 3 and Figure 5 As shown, the guide slide rod 1b is a telescopic rod structure with adjustable length. The main body of the guide slide rod 1b adopts a positive and negative thread rod structure with a locking nut to realize length adjustment and positioning locking.

[0056] The guide slide rod 1b adopts an adjustable rod structure with positive and negative threads, and relies on the locking screw sleeve to lock the rod length, which is used to calibrate the initial installation stroke and preload of the suspension.

[0057] The main mounting bracket 1 and the radar mounting base plate 2 also integrate an active obstacle crossing control system.

[0058] In summary, during operation, the main mounting bracket 1, the upper connecting beam 1a, and the guide slide rod 1b constitute a lateral limiting base. The lateral guide limiting block 1c limits the lateral offset travel of the mechanism. The lateral spring buffer assembly 1d works in conjunction with the internal main compression helical spring 1d3 and the viscous fluid damper 1d4 to absorb the lateral vibration and impact generated by the equipment's movement. The preload can be adjusted by fine-tuning the nut to adapt to different tunnel conditions.

[0059] The upper connecting beam 1a, guide slide rod 1b and lower connecting beam 2a1 form an adaptive four-bar structure, which together with the whole machine's parallelogram follow-up suspension system forms a two-level layered follow-up buffer system, which adaptively adapts to the overall curved surface and local concave and convex deformation of the tunnel.

[0060] The adjustable guide slide 1b can accurately calibrate the initial stroke and preload, and with the self-lubricating bearing hinge structure, it ensures smooth swing and low-wear operation of the mechanism.

[0061] The pre-tightened damping elastomer 2a2 built into the universal ball joint mechanism 2a can eliminate the hinge gap, suppress micro-vibration, and accurately limit the pitch and yaw angles of the radar mounting base plate 2, thereby achieving high-precision attitude compensation.

[0062] The radar mounting base plate 2 is made of low dielectric and low loss transparent material and has built-in wave-absorbing material to effectively shield electromagnetic interference. Combined with the roller assembly 2b, it can achieve constant distance to the wall and ensure stable and accurate detection data.

[0063] When the inspection encounters wall misalignment or protruding obstacles, the active obstacle crossing control system relies on sensors to collect working condition data in real time. After triggering the threshold, it drives the electric push rod to lift the equipment to complete the obstacle crossing. After crossing the obstacle, it automatically resets to stick to the wall, realizing continuous inspection operation.

[0064] The above embodiments only illustrate one or more implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.

Claims

1. An adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels, characterized in that, Includes the main mounting bracket (1) and the radar mounting base plate (2); The bottom of the main mounting bracket (1) is fixedly provided with an upper connecting beam (1a), and the upper connecting beam (1a) is equipped with two guide slide rods (1b) that can swing laterally; the bottom sides of the main mounting bracket (1) extend downward to form connecting parts, and the connecting parts on both sides are respectively equipped with lateral guide limiting blocks (1c) and lateral spring buffer assemblies (1d). The lateral guide limiting blocks (1c) are located at the end of the lateral offset path of the guide slide rods (1b) to limit the maximum lateral offset of the guide slide rods (1b). The lateral spring buffer assembly (1d) cooperates laterally with the guide slide rods (1b). The radar mounting base plate (2) is located directly below the main mounting bracket (1). A universal ball joint mechanism (2a) is fixedly installed at the center of the top surface of the radar mounting base plate (2). The universal ball joint mechanism (2a) includes a fixed end and a rotating end that rotate with each other. A lower connecting crossbeam (2a1) is fixedly assembled on the rotating end. The bottom of the two guide slide rods (1b) extends vertically and is hinged to the lower connecting beam (2a1). The upper connecting beam (1a), the two guide slide rods (1b), and the lower connecting beam (2a1) together constitute an adaptive four-bar swing structure. The bottom corner of the radar mounting base plate (2) is provided with roller assembly (2b) for moving along the tunnel wall.

2. The adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels according to claim 1, characterized in that, The fixed end and the rotating end of the universal ball joint mechanism (2a) are filled with a pre-tightened damping elastomer (2a2). The pre-tightened damping elastomer (2a2) is disposed in the ball joint fit gap, and its axial thickness or radial dimension determines the maximum swing angle of the ball joint rotating end relative to the fixed end.

3. The adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels according to claim 1, characterized in that, The lateral guide limiting block (1c) and the lateral spring buffer assembly (1d) are arranged vertically or obliquely relative to the connecting part to adapt to the curved surface posture of the tunnel and achieve normal pre-tightening to the wall and vibration impact absorption.

4. The adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels according to claim 1, characterized in that, The upper and lower ends of the guide slide rod (1b) are respectively hinged to the upper connecting beam (1a) and the lower connecting beam (2a1) through a pin structure with a self-lubricating bearing.

5. The adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels according to claim 3, characterized in that, The lateral spring buffer assembly (1d) includes: The outer sleeve (1d1) is hinged at its tail end to the inner wall of the connecting part of the main mounting bracket (1) via a cross shaft universal joint. The open end of the outer sleeve (1d1) is equipped with a fine-tuning nut. An inner slide rod (1d2) has one end slidably inserted into the outer sleeve (1d1) at one end, and the other end of the inner slide rod (1d2) is hinged to the middle of the guide slide rod (1b). The main compression helical spring (1d3) is coaxially sleeved on the outside of the inner slide rod (1d2), and the two ends of the main compression helical spring (1d3) abut against the limiting flange provided by the fine-adjusting nut and the inner slide rod (1d2), respectively. A viscous fluid damper (1d4) is arranged coaxially with the main compression helical spring (1d3), and the viscous fluid damper (1d4) outputs a damping force that is positively correlated with the extension and contraction speed.

6. The adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels according to claim 2, characterized in that, The radar mounting base plate (2) is made of a non-metallic wave-transparent material with low relative permittivity and low loss tangent, and the radar mounting base plate (2) is filled with radar wave-absorbing material to shield electromagnetic clutter from non-detection directions.

7. The adaptive flexible wall-adhering mechanism for radar monitoring of shield tunnels according to claim 5, characterized in that, The guide slide rod (1b) is a telescopic rod structure with adjustable length. The main body of the guide slide rod (1b) adopts a positive and negative thread rod structure with a locking nut to realize length adjustment and positioning locking.

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