A segment misalignment monitoring device based on multi-sensor fusion

Abstract

This invention discloses a segment misalignment monitoring device based on multi-sensor fusion, comprising a laser sensor, an optical flow sensor, a triaxial rotation sensor, a limiting component, a connecting plate, and a fixing component. The bottom of the fixing component is mounted on the segment. One end of the connecting plate is detachably connected to the fixing component, and the other end extends cantilevered above the adjacent segment. The end of the connecting plate away from the fixing component has a slot and a limiting component, and the laser sensor is installed in the slot. The limiting component passes through the connecting plate and is detachably connected to it. A protective shell is installed on the end of the limiting component facing the bottom of the fixing component, and the optical flow sensor is installed inside the protective shell. The triaxial rotation sensor is installed inside the fixing component. The fixing component also contains a control motherboard and a battery. The laser sensor, optical flow sensor, and triaxial rotation sensor are all electrically connected to the control motherboard. The monitoring device of this invention has a simple structure, is easy to install, and provides reliable monitoring data.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering monitoring technology, specifically relating to a segment misalignment monitoring device that integrates multi-source sensing technology for real-time acquisition of segment misalignment, relative displacement, and spatial attitude changes. Background Technology

[0002] Shield tunneling is the primary construction method for urban subways and underwater tunnels. As the main support structure of the tunnel, the joints of the shield tunnel segments are weak points in terms of structural stress and waterproofing. During construction and operation, factors such as ground stress release, uneven grouting pressure, train vibration loads, or uneven foundation settlement can easily cause relative displacement between adjacent segments, mainly manifested as vertical misalignment, joint opening, and planar shear slip. Therefore, obtaining parameters related to joint opening, misalignment, and attitude changes, and studying their influencing mechanisms, is of great significance for construction quality control and structural safety assessment.

[0003] Commonly used methods for monitoring tunnel segment joints in existing projects include manual measurement, dial indicators, micrometers, and built-in joint measuring instruments. These methods largely rely on manual setup and readings, resulting in significant data dispersion and difficulty in achieving continuous recording. Furthermore, while fiber optic sensing-based monitoring methods offer high accuracy, they are costly, complex to deploy, and have limitations in identifying minute deformations. Vision- or photogrammetry-based methods are highly dependent on the site environment and are sensitive to factors such as lighting, obstructions, and construction vibrations within the tunnel.

[0004] Traditional monitoring methods generally suffer from insufficient real-time performance, low automation, complex installation, and difficulty in simultaneously acquiring information on segment opening, misalignment, and attitude, making it difficult to meet the needs of multi-dimensional deformation monitoring of tunnel segments during shield tunneling. Therefore, there is an urgent need for a compact, attachable device capable of simultaneously acquiring displacement and attitude parameters and achieving continuous automatic monitoring. Summary of the Invention

[0005] To address the problems of manual measurement relying on experience, poor real-time performance, low efficiency, and large size and inconvenient installation of monitoring equipment in existing technologies, this invention provides a segment misalignment monitoring device based on multi-sensor fusion that can simultaneously acquire segment joint misalignment, rotation angle, and opening amount, thereby realizing real-time, continuous, and automatic monitoring of multi-dimensional deformation of shield tunnel segments.

[0006] The present invention provides a segment misalignment monitoring device based on multi-sensor fusion, comprising a laser sensor, an optical flow sensor, a triaxial rotation sensor, a limiting component, a connecting plate, and a fixing component;

[0007] The laser sensor is used to measure the vertical relative displacement between adjacent segments to obtain the vertical misalignment at the joint.

[0008] Optical flow sensors are used to measure the planar relative displacement between adjacent tube segments;

[0009] A three-axis rotation sensor is used to measure the attitude changes of the tunnel segment in space;

[0010] The bottom of the fixing member is installed on the tube segment. One end of the connecting plate is detachably connected to the fixing member, and the other end extends out to the upper part of the adjacent tube segment in a cantilever form. The end of the connecting plate away from the fixing member is provided with a slot and a limiting member respectively. The laser sensor is installed in the slot and its emitted beam points to the surface of the tube segment where the fixing member is located.

[0011] The limiting member passes through the connecting plate and is detachably connected to the connecting plate. A protective shell is installed on the end of the limiting member facing the bottom of the fixing member. The optical flow sensor is installed inside the protective shell. The protective shell is attached to the tube segment by adjusting the limiting member. It is used to measure the planar relative displacement between adjacent tube segments by identifying the surface texture features of the tube segment.

[0012] The fixing component is a hollow structure with movable cover plates at the top and bottom. The triaxial rotation sensor is installed inside the fixing component, which also contains a control motherboard and a battery to enable data processing, attitude correction, and independent power supply for the monitoring device.

[0013] The laser sensor, optical flow sensor, and triaxial rotation sensor are all electrically connected to the control motherboard to achieve continuous automatic acquisition of displacement and attitude data of the tunnel segment.

[0014] The limiting component includes a rod and a spring. The rod moves through a through hole in the connecting plate, and the spring is sleeved outside the rod and located between the protective shell and the connecting plate. A limiting nut is provided at the end of the rod away from the protective shell. By tightening the nut, the spring is compressed, so that the optical flow sensor can be stably attached to the surface of the tube segment under the elastic clamping force of the spring during the monitoring process, so as to realize the continuous measurement of the planar relative displacement between adjacent tube segments.

[0015] The bottom of the fastener is equipped with an adhesive or magnetic structure, which allows for quick and non-destructive installation without the need for external support components.

[0016] The connecting plate is provided with multiple connecting holes, and the fixing component is provided with receiving holes corresponding to the connecting holes. The signal lines of the laser sensor and the optical flow sensor pass through the connecting holes and receiving holes and are electrically connected to the control motherboard, and are connected through the control motherboard ribbon cable interface provided on the control motherboard.

[0017] The control motherboard is configured as follows:

[0018] The output data of the laser sensor, optical flow sensor and triaxial rotation sensor are collected synchronously according to the preset sampling frequency.

[0019] Based on the attitude angle information of the triaxial rotation sensor, the distance measured by the laser sensor is geometrically corrected to obtain the vertical misalignment between adjacent segments.

[0020] The relative planar displacement between adjacent segments is calculated based on the displacement of surface texture of the segments identified by the optical flow sensor, which is used to characterize the joint opening and lateral deformation.

[0021] The monitoring device of the present invention has the following beneficial effects:

[0022] 1. Multidimensional monitoring and data fusion: The innovative introduction of optical flow sensors in conjunction with laser sensors utilizes the inherent rough texture of the concrete surface of the tunnel segment as "natural feature points," allowing for the simultaneous measurement of planar slip and vertical misalignment without the need for manually setting up targets. Through the combined measurement of laser sensors and optical flow sensors, the vertical misalignment and planar relative displacement of the tunnel segment can be obtained separately, enabling real-time monitoring of joint misalignment and opening.

[0023] 2. Attitude compensation: A dual error compensation mechanism including "angle projection" and "arm displacement" was established, which effectively solved the measurement error problem caused by neglecting the installation tilt angle and cantilever rotation in traditional miniaturized equipment, and significantly improved the authenticity and reliability of monitoring data.

[0024] 3. This invention can be installed by pasting or magnetic attraction without the need for additional support structures, enabling rapid arrangement of adjacent pipe segments; the monitoring device has data storage and power supply capabilities, enabling continuous monitoring without human intervention.

[0025] 4. Strong engineering applicability: The device integrates power supply and storage modules, is small in size, wireless, and supports "plug and play", which greatly reduces the difficulty and cost of on-site implementation. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the monitoring device of the present invention;

[0027] Figure 2 This is a schematic diagram of the fastener of the present invention;

[0028] Figure 2-1 This is a bottom view of the fastener of the present invention;

[0029] Figure 3 This is a schematic diagram of the bottom inner structure of the fastener of the present invention;

[0030] Figure 4-1 This is a schematic diagram of the connecting plate structure of the present invention;

[0031] Figure 4-2 This is a bottom view of the connecting plate of the present invention;

[0032] Figure 5-1This is a schematic diagram of the assembly of the limiting component and the protective shell of the present invention;

[0033] Figure 5-2 This is a bottom view of the protective shell of the present invention;

[0034] Figure 6 This is a schematic diagram showing the arrangement of the monitoring device of the present invention on the tunnel lining segment;

[0035] The components include: 1. Laser sensor; 2. Triaxial rotation sensor; 3. Optical flow sensor; 4. Connecting plate; 5. Fixing component; 6. Control motherboard; 7. Battery; 8. Rod body; 9. Protective shell; 10. Slotted opening; 11. Spring; 12. Through hole; 13. Limit nut; 14. Connecting hole; 15. Receiving hole; 16. Tube segment I; 17. Tube segment II; 18. Control motherboard ribbon cable interface. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0037] See Figure 1 To Figure 6 ,like Figures 1 to 6 As shown, the present invention provides a multi-sensor fusion-based segment misalignment monitoring device, which includes a laser sensor 1, an optical flow sensor 3, a triaxial rotation sensor 2, a limiting component, a connecting plate 4, and a fixing component 5.

[0038] The laser sensor 1 is used to measure the vertical relative displacement between adjacent segments to obtain the vertical misalignment at the joint.

[0039] Optical flow sensor 3 is used to measure the planar relative displacement between adjacent tube segments;

[0040] The triaxial rotation sensor 2 is used to measure the attitude change of the tunnel segment in space, correct the measurement deviation of deformation caused by changes in the attitude of the tunnel segment such as plane rotation and structural deflection, and improve the overall accuracy of the monitoring results.

[0041] The bottom of the fixing member is installed on the tube segment. One end of the connecting plate is detachably connected to the fixing member 5, and the other end extends out to the upper part of the adjacent tube segment in a cantilever form. The end of the connecting plate away from the fixing member is provided with a slot 10 and a limiting member respectively. The laser sensor is installed in the slot, the detection direction is vertical, and its emitted beam points to the surface of the tube segment where the fixing member is located.

[0042] The limiting member passes through the connecting plate and is detachably connected to the connecting plate. A protective shell 9 is installed on one end of the limiting member facing the bottom of the fixing member. The optical flow sensor 3 is installed inside the protective shell. The protective shell is attached to the tube sheet by adjusting the limiting member.

[0043] The fixing component 5 is a hollow structure with movable cover plates at the top and bottom. The triaxial rotation sensor 2 is installed inside the fixing component to sense and monitor the spatial attitude angle of the device in real time. The fixing component also contains a control motherboard 6 and a battery 7. The battery provides continuous power to the control motherboard and various sensors, enabling the monitoring device of the present invention to operate independently for a long time.

[0044] The laser sensor 1, optical flow sensor 3, and triaxial rotation sensor 2 are all electrically connected to the control motherboard 6. The control motherboard is used to synchronously collect data and perform geometric compensation on the displacement data based on the spatial attitude angle.

[0045] The limiting component includes a rod 8 and a spring 11. The rod moves through the through hole 12 on the connecting plate. The spring is sleeved outside the rod and located between the protective shell and the connecting plate. A limiting nut 13 is provided at the end of the rod away from the protective shell. When the device is installed in place, the spring is in a compressed state, thereby generating a continuous vertical component force to ensure that the optical flow sensor 3 always maintains a tight fit with the surface of the tube when the tube experiences micro-movement or vibration.

[0046] The bottom of the fastener is equipped with an adhesive or magnetic structure to achieve non-destructive and rapid installation. If it is an adhesive structure, the fastener can be attached to the cleaned tube surface by removing the protective film during use, and the short side of the bottom of the monitoring device should be aligned with the edge of the tube.

[0047] The connecting plate is provided with a plurality of connecting holes 14, and the fastener is provided with receiving holes 15 corresponding to the connecting holes. The signal lines of the laser sensor 1 and the optical flow sensor 3 pass through the connecting holes and the receiving holes and are electrically connected to the control motherboard 6, and are connected through the control motherboard ribbon cable interface 18 provided on the control motherboard 6.

[0048] The control motherboard 6 is configured as follows:

[0049] The output data of laser sensor 1, optical flow sensor 3 and triaxial rotation sensor 2 are collected synchronously according to the preset sampling frequency.

[0050] Based on the attitude angle information of the triaxial rotation sensor 2, the distance measured by the laser sensor 1 is geometrically corrected to obtain the vertical misalignment between adjacent segments.

[0051] The relative planar displacement between adjacent segments is calculated based on the displacement of the surface texture of the tube segment identified by the optical flow sensor 3, which is used to characterize the joint opening and lateral deformation.

[0052] During the assembly of the monitoring device, the laser sensor 1 is first installed at the slot 10 of the connecting plate 4, and the signal line is led through the connecting hole and the receiving hole to the control main board 6; then the optical flow sensor 3 is installed in the protective shell 9, and then connected to the connecting plate 4 by the spring 11. After that, the connecting plate 4 is fixed to the fixing part 5 by fasteners, and the signal lines of each sensor are connected to the control main board 6.

[0053] In use, first fix the bottom of the fastener to the tube segment II17 using an adhesive or magnetic structure, and extend the connecting plate toward the adjacent tube segment I16 so that the protective shell 9 containing the optical flow sensor contacts the tube segment I16. Then tighten the limiting nut, which compresses the spring 11, and the elastic force of the spring adheres the protective shell to the tube segment I16.

[0054] When the monitoring device of the present invention is running normally, the control motherboard 6 starts the measurement program and drives the laser sensor 1 to emit a laser beam. The control motherboard 6 calculates the round-trip time of the laser to obtain the precise distance change from the monitor to the surface of the adjacent pipe segment, thereby obtaining the misalignment between the pipe segments.

[0055] The optical flow sensor 3 maintains constant force contact with the surface of the tube segment through the spring 11. During the measurement process, it continuously acquires texture images of the tube segment surface. By calculating the change in texture displacement between adjacent frames, it realizes the planar relative displacement measurement between tube segments, which is used to obtain the joint opening and lateral deformation.

[0056] The triaxial rotation sensor 2 is used to record the real-time changes in the attitude of the monitoring equipment, including pitch angle, roll angle and yaw angle; on the one hand, it can reflect the attitude state of the tunnel lining segments under construction or stress; on the other hand, it can correct the ranging error caused by the change in tilt angle of the laser sensor.

[0057] When the tube segment rotates, the incident direction of the laser beam is no longer perpendicular to the surface being measured, causing a system deviation in laser ranging. The control motherboard 6 performs geometric compensation on the ranging value based on the attitude angle provided by the triaxial rotation sensor 2 to improve the measurement accuracy of misalignment and opening.

[0058] The error compensation algorithm is based on spatial geometric projection. The error compensation logic is designed for the complex geometric environment inside the tunnel. It uses the built-in three-axis rotation sensor 2 to sense the tilt angle of the equipment in real time and eliminates the projection error caused by uneven installation or tunnel segment torsion through the algorithm in the control motherboard, which significantly improves the authenticity of the data.

[0059] The inside of the fixing component 5 is a sealed cavity. The control motherboard 6 is the core of the system. The triaxial rotation sensor 2 is fixed on the control motherboard 6, and the center point of the triaxial rotation sensor 2 is defined as the "rotation center" of the device.

[0060] A key innovation of this invention is the establishment of a dual error compensation model that includes "angle projection" and "arm displacement". In the structural design, the optical center of the laser sensor 1 and the center of the triaxial rotation sensor 2 have a fixed structural offset distance L along the tunnel direction (X-axis).

[0061] In actual working conditions, the attitude of the monitoring device is relatively more complex. To facilitate calculation, the attitude is decomposed into: pitch angle (θ), i.e., rotation around the Y-axis (cantilever swinging up and down); and roll angle (φ), i.e., rotation around the X-axis (cantilever rolling laterally). Both of these rotations will cause measurement errors. The control motherboard 6 adopts the following step-by-step correction model:

[0062] (1) Dual-axis tilt correction of laser beam path (solving the "oblique projection" problem):

[0063] Whether the device tilts forward or backward, or tilts left or right, the laser beam will deviate from the vertical direction, resulting in a change in the measured distance. The hypotenuse becomes the spatial hypotenuse, greater than the actual perpendicular distance; according to the application of the Pythagorean theorem in three-dimensional space, the actual projected height... The tilt angles in two directions need to be corrected:

[0064]

[0065] The cos(φ) term is specifically used to eliminate the lateral oblique projection error of the laser caused by the device tilting around the X-axis (rod rotation), while the cos(θ) term is used to eliminate the oblique projection error caused by longitudinal tilt.

[0066] (2) Correction of the lever arm effect of the cantilever (solving the "probe lifting" problem):

[0067] Since the laser sensor (1) is installed at the front end of the connecting plate (cantilever), there is a horizontal distance L between it and the rotation center located in the control main board; when the device pitches (θ), the end of the cantilever will physically rise or fall; according to the sine principle, the change in height Δh is:

[0068]

[0069] (3) Final solution formula:

[0070] The system superimposes the optical path correction and position correction, and subtracts the initial calibration value. This yields extremely high precision in the vertical misalignment measurement. :

[0071]

[0072] Through the above algorithm, the monitoring device of the present invention not only solves the sensor position error caused by the swing of the cantilever, but also perfectly solves the problem of laser oblique projection caused by the device overturning, ensuring that the true distance perpendicular to the surface of the tube can be obtained under any posture; at the same time, for the planar displacement data measured by the optical flow sensor 3, the control motherboard will also combine the posture angle to construct a rotation matrix for projection correction, so as to eliminate the false displacement components caused by the tilt of the equipment.

[0073] This invention adopts an integrated design, making the monitoring instrument small in size and easy to install. It can operate independently for at least 40 hours, enabling continuous monitoring of misalignment, opening amount, and attitude changes of adjacent segments, significantly improving monitoring accuracy and construction efficiency.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A segment misalignment monitoring device based on multi-sensor fusion, characterized in that: Includes a laser sensor (1), an optical flow sensor (3), a triaxial rotation sensor (2), a limiting component, a connecting plate (4), and a fixing component (5); The laser sensor is used to measure the vertical relative displacement between adjacent segments to obtain the vertical misalignment at the joint. Optical flow sensors are used to measure the planar relative displacement between adjacent segments; The triaxial rotation sensor is used to measure the attitude changes of the tunnel lining segments in space; The bottom of the fixing member is installed on the tube segment. One end of the connecting plate is detachably connected to the fixing member (5), and the other end extends out to the upper part of the adjacent tube segment in a cantilever form. The end of the connecting plate away from the fixing member is provided with a slot (10) and a limiting member respectively. The laser sensor is installed in the slot and its emitted beam points to the surface of the tube segment where the fixing member is located. The limiting member passes through the connecting plate and is detachably connected to the connecting plate. A protective shell (9) is installed on one end of the limiting member facing the bottom of the fixing member. The optical flow sensor (3) is installed inside the protective shell. The protective shell is attached to the tube sheet by adjusting the limiting member. The fixing component (5) is a hollow structure. The three-axis rotation sensor (2) is installed inside the fixing component. The fixing component also contains a control motherboard (6) and a battery (7). The laser sensor (1), optical flow sensor (3) and triaxial rotation sensor (2) are all electrically connected to the control motherboard (6).

2. The segment misalignment monitoring device based on multi-sensor fusion according to claim 1, characterized in that, The limiting component includes a rod (8) and a spring (11). The rod moves through the through hole (12) on the connecting plate. The spring is sleeved outside the rod and located between the protective shell and the connecting plate. A limiting nut (13) is provided at the end of the rod away from the protective shell.

3. The segment misalignment monitoring device based on multi-sensor fusion according to claim 1, characterized in that, The bottom of the fastener is equipped with an adhesive or magnetic structure to achieve non-destructive and rapid installation.

4. The segment misalignment monitoring device based on multi-sensor fusion according to claim 1, characterized in that, The connecting plate is provided with multiple connecting holes (14), and the fastener is provided with receiving holes (15) corresponding to the connecting holes. The signal lines of the laser sensor (1) and the optical flow sensor (3) pass through the connecting holes and receiving holes and are electrically connected to the control motherboard (6).

5. The segment misalignment monitoring device based on multi-sensor fusion according to any one of claims 1-4, characterized in that, The control motherboard (6) is configured as follows: The output data of the laser sensor (1), optical flow sensor (3) and triaxial rotation sensor (2) are collected synchronously according to the preset sampling frequency. Based on the attitude angle information of the triaxial rotation sensor (2), the distance measured by the laser sensor (1) is geometrically corrected to obtain the vertical misalignment between adjacent segments; The relative planar displacement between adjacent segments is calculated based on the displacement of the surface texture of the tube segment identified by the optical flow sensor (3), which is used to characterize the joint opening and lateral deformation.

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