A single six-degree-of-freedom displacement meter based on magnetic grid sensor and a measuring method thereof
The single-unit six-degree-of-freedom displacement gauge using a magnetic grating sensor solves the problem of the inability to detect the relative torsional angle of a structure and measurement errors in existing technologies, and realizes accurate measurement of six-degree-of-freedom displacement. It is suitable for various engineering monitoring needs, especially dynamic real-time monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGXI KAIRUNDA PRECISION INSTR CO LTD
- Filing Date
- 2026-01-23
- Publication Date
- 2026-07-21
AI Technical Summary
Existing single-unit three-dimensional joint gauges cannot detect the relative torsional angle between structures around any coordinate axis, and the measurement principle has potential errors, resulting in inaccurate measurement results under complex deformation conditions.
A single six-degree-of-freedom displacement meter based on a magnetic grating sensor is used. By combining linear displacement sensors and angular displacement sensors, the direct measurement of six-degree-of-freedom displacements between structures is realized, including relative translation in the X, Y, and Z axes and relative rotation around the X, Y, and Z axes. The non-contact measurement method of the magnetic grating sensor avoids intermediate physical quantity conversion and errors.
It achieves precise measurement across all six degrees of freedom, reducing installation difficulty and cost. It is suitable for space-constrained environments, has high measurement accuracy, and a wide range of applications, applicable to both conventional structures and fragile objects. It can perform dynamic real-time monitoring.
Smart Images
Figure CN121702259B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water conservancy and hydropower engineering monitoring technology, specifically to a single six-degree-of-freedom displacement meter based on a magnetic grating sensor and its measurement method. Background Technology
[0002] In engineering fields such as water conservancy and hydropower, civil engineering and transportation, long-term and accurate monitoring of the relative displacement between adjacent structures (such as the joint panels of concrete-faced dams, the transverse joints between dam sections, and the expansion joints of bridges) is crucial for assessing the overall integrity, safety, and operational status of the structure. The relative motion between structures has six degrees of freedom in space, including linear translations along the X, Y, and Z axes (such as opening and closing, displacement, and settlement) and rotations about the X, Y, and Z axes (such as torsion and tilting).
[0003] Currently, for the monitoring of three-dimensional displacement of structural joints or seams, the traditional split-type scheme, consisting of three independent unidirectional displacement gauges orthogonally assembled in space, has evolved into a more integrated single-unit three-dimensional joint gauge (as described in Chinese patent document CN118857069A). This type of device typically consists of an axially extendable displacement gauge and composite hinged supports at both ends. By measuring the axial linear displacement and the angular changes in two directions at the supports, the relative translational amounts (ΔX, ΔY, ΔZ) between the two monitoring points in three-dimensional space are indirectly calculated. This single-unit design simplifies installation and reduces size to some extent.
[0004] However, in-depth analysis and engineering practice have revealed that existing single-unit three-dimensional joint gauges still have significant technical limitations. First, they lack complete functional dimensions. Their design and measurement models are only for three-dimensional relative translation, and they are completely unable to detect the relative torsional angle between two structures around any coordinate axis. In actual engineering, due to factors such as uneven foundation settlement, load eccentricity, and seismic action, adjacent structures generally undergo varying degrees of relative micro-rotation around the vertical direction (Z-axis) or the horizontal direction (X, Y-axis), which is especially evident when there is a large relative displacement. This rotation is an important source of information reflecting the overall deformation mode and safety status of the structure. The lack of existing technology results in a blind spot in the monitoring of this key degree of freedom.
[0005] Secondly, the measurement principle has potential errors. The solution model of the existing single-unit three-way joint gauge is based on an implicit assumption that the bottom surfaces of the two mounting supports (i.e. the connection surfaces with the structure) always remain parallel. When relative torsion occurs between the structures that is not detected by the sensors, this assumption no longer holds. At this time, the relative displacement of the top of the two supports is not the same as the relative displacement between the measuring points at the bottom of the supports, which leads to the distortion of the final calculated translational displacement in the three directions (ΔX, ΔY, ΔZ). That is, under the working conditions of complex deformation (translation accompanied by torsion), the accuracy and reliability of its measurement results are greatly reduced. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a single six-degree-of-freedom displacement meter based on a magnetic grating sensor and its measurement method, so as to solve the problems mentioned in the background art.
[0007] A single-unit six-degree-of-freedom displacement meter based on a magnetic grating sensor includes: A magnetic grating displacement gauge includes a sleeve, a first pull rod and a second pull rod installed inside the sleeve, a bracket fixed to the inner wall of the sleeve, a linear displacement sensor and a first angular displacement sensor. The first pull rod is rotatably connected to one end of the sleeve, and the second pull rod is slidably connected to the other end of the sleeve. The linear displacement sensor is used to detect the linear displacement of the second pull rod relative to the sleeve, and the first angular displacement sensor is used to detect the angle of rotation of the first pull rod relative to the sleeve about its axis. A first composite measuring support hinged to the end of the first tie rod; And a second composite measuring support hinged to the end of the second tie rod; The first composite measuring support is provided with two angular displacement sensors for detecting its relative angular displacement with respect to the first tie rod in a direction about a first directional axis and in a direction about a second directional axis orthogonal to the first directional axis; the first directional axis is parallel to the normal direction of the mounting base surface of the first composite measuring support; The second composite measuring support is equipped with two angular displacement sensors for detecting its relative angular displacement with respect to the second tie rod on a third directional axis and a fourth directional axis orthogonal to the third directional axis; the third directional axis is parallel to the normal direction of the mounting base surface of the second composite measuring support; The measured values output by the linear displacement sensor, the first angular displacement sensor, and the four angular displacement sensors mounted on the first and second composite measurement supports are used to calculate the six-degree-of-freedom relative pose between the two structures on which the first and second composite measurement supports are mounted.
[0008] Preferably, the first composite measuring support includes a first base, a first hinge component rotatable about the vertical axis of the first base, a second angular displacement sensor, and a third angular displacement sensor; the second angular displacement sensor is used to detect the angular displacement of the first hinge component rotating about the vertical axis of the first base; the first hinge component is connected to the first pull rod by a first bolt, so that the first pull rod can rotate about the first bolt, and the third angular displacement sensor is used to detect the angular displacement of the first pull rod rotating about the first bolt; The second composite measuring support includes a second base, a second hinge component that can rotate around the vertical axis of the second base, a fourth angular displacement sensor, and a fifth angular displacement sensor; the fourth angular displacement sensor is used to detect the angular displacement of the second hinge component rotating around the vertical axis of the second base; the second hinge component is connected to the second tie rod by a second bolt, so that the second tie rod can rotate around the second bolt, and the fifth angular displacement sensor is used to detect the angular displacement of the second tie rod rotating around the second bolt.
[0009] Preferably, the linear displacement sensor, the first angular displacement sensor, the second angular displacement sensor, the third angular displacement sensor, the fourth angular displacement sensor, and the fifth angular displacement sensor are all magnetic grating sensors.
[0010] Preferably, the linear displacement sensor is a magnetic grating linear displacement sensor, which includes a magnetic grating ruler, a sixth magnetic head, and a sixth detection circuit board. The magnetic grating ruler is fixed on the second pull rod, the sixth detection circuit board is fixed on the bracket, and the sixth magnetic head is mounted on the sixth detection circuit board and is positioned opposite to the magnetic grating ruler.
[0011] Preferably, the first angular displacement sensor is a magnetic grating type angular displacement sensor, which includes a first magnetic grating disk, a first magnetic head and a first detection circuit board. The first magnetic grating disk is fixed to the end of the first pull rod located inside the sleeve, the first detection circuit board is fixed to the inner wall of the sleeve, and the first magnetic head is mounted on the first detection circuit board and is disposed opposite to the first magnetic grating disk.
[0012] Preferably, the second angular displacement sensor is a magnetic grating type angular displacement sensor, which includes a second magnetic grating disk, a second magnetic head, and a second detection circuit board. The second magnetic grating disk is fixed to the lower end of the first hinge component, the second detection circuit board is installed on the inner wall of the first base, and the second magnetic head is installed on the second detection circuit board and is arranged opposite to the second magnetic grating disk. The third angular displacement sensor is a magnetic grating type angular displacement sensor, which includes a third magnetic grating disk, a third magnetic head, and a third detection circuit board. The third magnetic grating disk is fixed to the end of the first bolt, the third detection circuit board is fixed to the side plate of the first hinge component, and the third magnetic head is mounted on the third detection circuit board and is arranged opposite to the third magnetic grating disk.
[0013] Preferably, the fourth angular displacement sensor is a magnetic grating angular displacement sensor, which includes a fourth magnetic grating disk, a fourth magnetic head, and a fourth detection circuit board. The fourth magnetic grating disk is fixed to the lower end of the second hinge component, the fourth detection circuit board is installed on the inner wall of the second base, and the fourth magnetic head is installed on the fourth detection circuit board and is arranged opposite to the fourth magnetic grating disk. The fifth angular displacement sensor is a magnetic grating type angular displacement sensor, which includes a fifth magnetic grating disk, a fifth magnetic head, and a fifth detection circuit board. The fifth magnetic grating disk is fixed to the end of the second bolt, the fifth detection circuit board is fixed to the side plate of the second hinge component, and the fifth magnetic head is mounted on the fifth detection circuit board and is arranged opposite to the fifth magnetic grating disk.
[0014] Preferably, protective covers are fixed to the side plates of the first hinge component and the second hinge component, and the protective covers enclose the third angular displacement sensor and the fifth angular displacement sensor.
[0015] Preferably, a sealing and waterproof component is provided between the protective cover and the corresponding first hinge component or second hinge component.
[0016] A measurement method for a single six-degree-of-freedom displacement gauge based on a magnetic grating sensor, as described in any of the above claims, includes the following steps: S1. Arrange the magnetic grating displacement gauge horizontally, and fix the first composite measuring support and the second composite measuring support on the two structures to be measured respectively, so as to ensure that the magnetic grating displacement gauge is in a horizontal position in the initial state. S2. Establish a spatial coordinate system with the center A of the bottom surface of the first composite measuring support as the origin, the initial line connecting the center A of the bottom surface of the first composite measuring support and the center B of the bottom surface of the second composite measuring support as the X-axis, the horizontal direction perpendicular to the X-axis as the Y-axis, and the vertical direction as the Z-axis. S3. When the two structures move relative to each other, read the linear displacement change measured by the linear displacement sensor, and the five angular displacements measured by the first angular displacement sensor, the second angular displacement sensor, the third angular displacement sensor, the fourth angular displacement sensor, and the fifth angular displacement sensor respectively. S4. Based on spatial geometric relationships and the Euler angular coordinate transformation matrix, using one linear displacement and five angular displacements obtained in step S3, calculate the relative translational displacements between the two structures in the X, Y, and Z directions, as well as the relative rotation angles around the X, Y, and Z axes.
[0017] The beneficial effects of this invention are as follows: 1. This invention achieves precise measurement in all six degrees of freedom, completely overcoming the limitation of existing single-unit three-dimensional seam measuring instruments that can only measure three-dimensional translation. Through innovative mechanical structure layout and coordinated configuration of six magnetic grating sensors, it achieves for the first time on a single device the synchronous and direct measurement of the complete six-degree-of-freedom displacement between two structures in the X, Y, and Z directions and the relative rotation around the X, Y, and Z axes. The measurement of each degree of freedom is independent of each other, the solution model is complete, and the translation measurement error caused by unknown torsion is avoided. 2. This invention retains the advantages of single-unit integrated design, inheriting the advantages of compact structure, small size and convenient installation of single-unit design. On site, it is only necessary to fix the two composite measuring supports to the structure to be measured respectively. There is no need for complicated spatial support assembly, which greatly reduces the installation difficulty and protection cost. It is especially suitable for monitoring occasions with limited space (such as corridors inside dams). 3. This invention has high measurement accuracy and a wide range. All core sensing elements are magnetic grating sensors, which directly measure displacement and angle without intermediate physical quantity conversion, zero drift and cumulative error (absolute value encoding). The measurement accuracy is high. The magnetic grating sensor itself has the characteristic of a large measurement range. By customizing sensors of different specifications and adjusting the support size, it can flexibly adapt to different measurement range requirements from millimeters to hundreds of millimeters. 4. This invention provides non-contact and non-destructive monitoring. The magnetic grating sensor is a non-contact measurement method. During the monitoring process, no large force is transmitted to the measured structure, which will not cause additional stress or damage to it. It has a wide range of applications. In addition to conventional concrete and steel structures, it is also suitable for fine monitoring of fragile objects such as ancient buildings and cultural relic protection structures. 5. This invention has flexible configuration and wide application scenarios. The sensor has a high degree of modularity. When only three-dimensional translation needs to be monitored, it can be simplified and used as a high-performance single three-dimensional gap measuring instrument. When only one-dimensional displacement needs to be monitored, it can be used as a precision linear displacement meter. This flexibility enables the product to better adapt to diverse engineering monitoring needs. 6. This invention enables dynamic real-time monitoring. The single six-degree-of-freedom displacement meter based on the magnetic grating sensor adopts a magnetic grating sensor, which responds to displacement changes in real time and has strong resistance to shock and vibration. It can continuously, accurately, and in real time measure, which is convenient for automated real-time online monitoring. It is particularly suitable for dynamic monitoring application scenarios with high-frequency data acquisition. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the overall invention.
[0019] Figure 2 This is a schematic cross-sectional view of the entire invention.
[0020] Figure 3 This is a schematic diagram of the left cross-section of the first composite measuring support of the present invention.
[0021] Figure 4 This is a schematic diagram of the right-side cross-section of the second composite measuring support of the present invention.
[0022] Figure 5 This is a schematic diagram of the single-unit six-degree-of-freedom displacement meter measurement method of the present invention.
[0023] In the diagram: 1-Magnetic grating displacement gauge, 11-Sleeve, 12-First tie rod, 13-Second tie rod, 14-Bracket, 15-Linear displacement sensor, 151-Magnetic grating ruler, 152-Sixth detection circuit board, 16-First angular displacement sensor, 161-First magnetic grating disk, 162-First detection circuit board, 2-First composite measuring support, 21-First base, 22-First hinge component, 23-First bolt, 24-Second angular displacement sensor, 241-Second magnetic grating disk, 242-Second detection circuit board, 25-Third angular displacement sensor, 251-Third magnetic grating disk, 252-Third detection circuit board, 3-Second composite measuring support, 31-Second base, 32-Second hinge component, 33-Second bolt, 34-Fourth angular displacement sensor, 341-Fourth magnetic grating disk, 342-Fourth detection circuit board, 35-Fifth angular displacement sensor, 351-Fifth magnetic grating disk, 352-Fifth detection circuit board, 4-Protective cover. Detailed Implementation
[0024] Please see Figures 1-4 A single six-degree-of-freedom displacement meter based on a magnetic grating sensor includes a magnetic grating displacement meter 1, a first composite measurement support 2, and a second composite measurement support 3. The first composite measurement support 2 and the second composite measurement support 3 are identical structures that are symmetrical to each other. The magnetic grating displacement meter 1, which integrates linear and angle measurement functions, serves as the core sensing unit. Combined with the two composite measurement supports, each integrating multi-angle measurement functions, a complete measurement system is constructed. The two composite supports are fixed on two structures to be measured, and the magnetic grating displacement meter 1 is connected between them. Through the coordinated work of the six internal sensors, the system decomposes and converts the complex spatial relative motion (i.e., displacement and rotation of six degrees of freedom) between the two structures into six linear or angle parameters that can be accurately measured, thereby realizing the calculation basis from one-dimensional physical quantities to six-dimensional spatial pose.
[0025] The magnetic grating displacement gauge 1 includes a sleeve 11, a first pull rod 12 and a second pull rod 13 installed inside the sleeve 11, a bracket 14 fixed to the inner wall of the sleeve 11, a linear displacement sensor 15, and a first angular displacement sensor 16. The first pull rod 12 is rotatably connected to one end of the sleeve 11, and the second pull rod 13 is slidably connected to the other end of the sleeve 11. The linear displacement sensor 15 is used to detect the linear displacement of the second pull rod 13 relative to the sleeve 11, and the first angular displacement sensor 16 is used to detect the angle of rotation of the first pull rod 12 relative to the sleeve 11 about its axis. When the second pull rod 13 is displaced, the linear displacement sensor 15 can detect the relative linear displacement of the second pull rod 13, and when the sleeve 11 rotates, the first angular displacement sensor 16 detects the angle of rotation of the magnetic grating displacement gauge 1 about its own central axis.
[0026] The first tie rod 12 is hinged to a first composite measuring support 2. The first composite measuring support 2 is equipped with two angular displacement sensors for detecting its relative angular displacement with respect to the first tie rod 12 about a first direction axis and about a second direction axis orthogonal to the first direction axis. The first direction axis is parallel to the normal direction of the mounting base surface of the first composite measuring support 2. The first composite measuring support 2 includes a first base 21, a first hinge component 22 rotatable about the vertical axis of the first base 21, a second angular displacement sensor 24, and a third angular displacement sensor 25. The second angular displacement sensor 24 is used to detect the angular displacement of the first hinge component 22 rotating about the vertical axis of the first base 21. The connecting component 22 is connected to the first pull rod 12 by the first bolt 23, so that the first pull rod 12 can rotate around the first bolt 23. The third angular displacement sensor 25 is used to detect the angular displacement of the first pull rod 12 rotating around the first bolt 23. When the axial direction of the magnetic grating displacement meter 1 deflects vertically, the first pull rod 12 deflects vertically simultaneously. At this time, the third angular displacement sensor 25 measures the vertical deflection angle of the magnetic grating displacement meter 1. When the axial direction of the magnetic grating displacement meter 1 deflects horizontally, the first hinge component 22 will be driven by the first pull rod 12 to rotate horizontally simultaneously. At this time, the second angular displacement sensor 24 measures the horizontal deflection angle of the magnetic grating displacement meter 1.
[0027] The second tie rod 13 is hinged to a second composite measuring support 3. The second composite measuring support 3 is equipped with two angular displacement sensors for detecting its relative angular displacement with respect to the second tie rod 13 about a third directional axis and about a fourth directional axis orthogonal to the third directional axis. The third directional axis is parallel to the normal direction of the mounting base surface of the second composite measuring support 3. The second composite measuring support 3 includes a second base 31, a second hinge component 32 rotatable about the vertical axis of the second base 31, a fourth angular displacement sensor 34, and a fifth angular displacement sensor 35. The fourth angular displacement sensor 34 is used to detect the angular displacement of the second hinge component 32 rotating about the vertical axis of the second base 31. The connecting component 32 is connected to the second pull rod 13 by the second bolt 33, allowing the second pull rod 13 to rotate around the second bolt 33. The fifth angular displacement sensor 35 is used to detect the angular displacement of the second pull rod 13 rotating around the second bolt 33. When the axial direction of the magnetic grating displacement meter 1 deflects vertically, the second pull rod 13 deflects vertically simultaneously. At this time, the fifth angular displacement sensor 35 measures the vertical deflection angle of the magnetic grating displacement meter 1. When the axial direction of the magnetic grating displacement meter 1 deflects horizontally, the second hinge component 32 will be driven by the second pull rod 13 to rotate horizontally simultaneously. At this time, the fourth angular displacement sensor 34 measures the horizontal deflection angle of the magnetic grating displacement meter 1.
[0028] The linear displacement sensor 15 is a magnetic grating type linear displacement sensor, which includes a magnetic grating ruler 151, a sixth magnetic head, and a sixth detection circuit board 152. The magnetic grating ruler 151 is fixed on the second pull rod 13, and the sixth detection circuit board 152 is fixed on the bracket 14. The sixth magnetic head is mounted on the sixth detection circuit board 152 and is positioned opposite to the magnetic grating ruler 151. When the second pull rod 13 is displaced, it can drive the magnetic grating ruler 151 to move synchronously. At this time, a relative displacement occurs between the magnetic grating ruler 151 and the sixth magnetic head. The sixth magnetic head can detect this displacement change and transmit the signal to the sixth detection circuit board 152, thereby realizing the detection of the relative linear displacement of the second pull rod 13.
[0029] The first angular displacement sensor 16 is a magnetic grating type angular displacement sensor, which includes a first magnetic grating disk 161, a first magnetic head, and a first detection circuit board 162. The first magnetic grating disk 161 is fixed to the end of the first pull rod 12 located inside the sleeve 11. The first detection circuit board 162 is fixed to the inner wall of the sleeve 11. The first magnetic head is mounted on the first detection circuit board 162 and is positioned opposite to the first magnetic grating disk 161. When the sleeve 11 rotates, it drives the first detection circuit board 162 to rotate synchronously. At this time, the first magnetic head on the first detection circuit board 162 and the first magnetic grating disk 161 at the end of the first pull rod 12 deflect at the same angle. The first magnetic head can detect this deflection angle and transmit the signal to the first detection circuit board 162, thereby realizing the angle detection of the magnetic grating displacement sensor 1 rotating around its own central axis.
[0030] The second angular displacement sensor 24 is a magnetic grating type angular displacement sensor, which includes a second magnetic grating disk 241, a second magnetic head, and a second detection circuit board 242. The second magnetic grating disk 241 is fixed to the lower end of the first hinge component 22. The second detection circuit board 242 is installed on the inner wall of the first base 21. The second magnetic head is installed on the second detection circuit board 242 and is arranged opposite to the second magnetic grating disk 241. When the axial direction of the magnetic grating displacement meter 1 deflects horizontally, the first hinge component 22 will be driven by the first pull rod 12 to rotate horizontally synchronously. The first hinge component 22 drives the second magnetic grating disk 241 to rotate synchronously. At this time, the second magnetic head can measure the deflection angle of the second magnetic grating disk 241 and transmit the signal to the second detection circuit board 242, thereby measuring the horizontal deflection angle of the magnetic grating displacement meter 1.
[0031] The third angular displacement sensor 25 is a magnetic grating type angular displacement sensor, which includes a third magnetic grating disk 251, a third magnetic head, and a third detection circuit board 252. The third magnetic grating disk 251 is fixed to the end of the first bolt 23, and the third detection circuit board 252 is fixed to the side plate of the first hinge component 22. The third magnetic head is mounted on the third detection circuit board 252 and is positioned opposite to the third magnetic grating disk 251. When the axial direction of the magnetic grating displacement meter 1 deflects vertically, the first pull rod 12 is sleeved outside the first bolt 23 and fixed to the first bolt 23 by screws. Therefore, the first pull rod 12 can drive the first bolt 23 to rotate synchronously, and the first bolt 23 drives the third magnetic grating disk 251 to rotate synchronously. At this time, the third magnetic head can measure the deflection angle of the third magnetic grating disk 251 and transmit the signal to the third detection circuit board 252 to measure the vertical deflection angle of the magnetic grating displacement meter 1.
[0032] The fourth angular displacement sensor 34 is a magnetic grating type angular displacement sensor, which includes a fourth magnetic grating disk 341, a fourth magnetic head, and a fourth detection circuit board 342. The fourth magnetic grating disk 341 is fixed to the lower end of the second hinge component 32. The fourth detection circuit board 342 is installed on the inner wall of the second base 31. The fourth magnetic head is installed on the fourth detection circuit board 342 and is positioned opposite to the fourth magnetic grating disk 341. When the axial direction of the magnetic grating displacement meter 1 deflects horizontally, the second hinge component 32 will be driven by the second pull rod 13 to rotate horizontally synchronously. The second hinge component 32 drives the fourth magnetic grating disk 341 to rotate synchronously. At this time, the fourth magnetic head can measure the deflection angle of the fourth magnetic grating disk 341 and transmit the signal to the fourth detection circuit board 342, thereby measuring the horizontal deflection angle of the magnetic grating displacement meter 1.
[0033] The fifth angular displacement sensor 35 is a magnetic grating type angular displacement sensor, which includes a fifth magnetic grating disk 351, a fifth magnetic head, and a fifth detection circuit board 352. The fifth magnetic grating disk 351 is fixed to the end of the second bolt 33, and the fifth detection circuit board 352 is fixed to the side plate of the second hinge component 32. The fifth magnetic head is mounted on the fifth detection circuit board 352 and is positioned opposite to the fifth magnetic grating disk 351. When the axial direction of the magnetic grating displacement meter 1 deflects vertically, because the second pull rod 13 is sleeved outside the second bolt 33 and fixed to the second bolt 33 by screws, the second pull rod 13 drives the second bolt 33 to rotate synchronously, and the second bolt 33 drives the fifth magnetic grating disk 351 to rotate synchronously. At this time, the fifth magnetic head can measure the deflection angle of the fifth magnetic grating disk 351 and transmit the signal to the fifth detection circuit board 352, thereby measuring the vertical deflection angle of the magnetic grating displacement meter 1.
[0034] Protective covers 4 are fixed to the side plates of the first hinge component 22 and the second hinge component 32, respectively. The protective covers 4 enclose the third angular displacement sensor 25 and the fifth angular displacement sensor 35. The main function of the protective covers 4 is to provide physical protection. By covering the outside of the hinge component, it forms a closed space to protect the precision third angular displacement sensor 25 and the fifth angular displacement sensor 35. This can effectively prevent direct impact or intrusion of external solid foreign objects (such as dust and gravel), as well as avoid accidental human contact or mechanical damage, and ensure that the third angular displacement sensor 25 and the fifth angular displacement sensor 35 can work reliably for a long time in complex industrial or field environments, maintaining measurement accuracy and lifespan.
[0035] A sealing and waterproof component (such as a gasket) is provided between the protective cover 4 and the corresponding first hinge component 22 or second hinge component 32. The sealing and waterproof component is filled in the gap between the protective cover 4 and the hinge component. It achieves tight contact through elastic deformation, forming a barrier. This barrier can effectively prevent the intrusion of media such as liquid water, water vapor, oil, and corrosive gases, creating a dry and clean microenvironment for the internal sensor. This is a key protective measure to ensure that the displacement gauge can still work normally under harsh conditions such as humidity, dust, and rain, and improves the environmental adaptability and reliability of the entire measurement system.
[0036] In summary, the measured values output by the linear displacement sensor 15, the first angular displacement sensor 16, and the four angular displacement sensors mounted on the first composite measuring support 2 and the second composite measuring support 3 are used to calculate the six-degree-of-freedom relative pose between the two structures mounted on the first composite measuring support 2 and the second composite measuring support 3. The linear displacement sensor 15, the first angular displacement sensor 16, the second angular displacement sensor 24, the third angular displacement sensor 25, the fourth angular displacement sensor 34, and the fifth angular displacement sensor 35 are all magnetic grating sensors. Through an innovative mechanical structure layout and the coordinated configuration of six magnetic grating sensors, for the first time, synchronous and direct measurement of the complete six-degree-of-freedom displacement between two structures—relative translation in the X, Y, and Z axes and relative rotation around the X, Y, and Z axes—is achieved on a single device. Each degree of freedom measurement is independent, the calculation model is complete, and the problem of... Due to the unknown torsional movement causing translational measurement errors, and because all measurements are taken using magnetic grating sensors, displacement and angle are directly measured without intermediate physical quantity conversion, zero drift, or cumulative error (absolute value encoding). This results in high measurement accuracy. Magnetic grating sensors themselves have a large measurement range; by customizing different sensor specifications and adjusting support dimensions, they can flexibly adapt to different measurement ranges from millimeters to hundreds of millimeters. Furthermore, magnetic grating sensing is a non-contact measurement method, meaning no large force is transmitted to the measured structure during monitoring, preventing additional stress or damage. Its applicability is extremely wide, suitable not only for conventional concrete and steel structures but also for the fine monitoring of fragile objects such as ancient buildings and cultural relic protection structures. It responds to displacement changes in real time, has strong resistance to impact and vibration, and can perform continuous, accurate, and real-time measurements, facilitating automated real-time online monitoring. It is particularly suitable for dynamic monitoring applications requiring high-frequency data acquisition.
[0037] Please see Figure 5 A measurement method for a single six-degree-of-freedom displacement gauge based on a magnetic grating sensor, according to any one of the above, includes the following steps: S1. Arrange the magnetic grating displacement meter 1 horizontally, and fix the first composite measuring support 2 and the second composite measuring support 3 on the two structures to be measured respectively, so as to ensure that the magnetic grating displacement meter 1 is in a horizontal position in the initial state. S2. Establish a spatial coordinate system with the center A of the bottom surface of the first composite measuring support 2 as the origin, the initial line connecting the center A of the bottom surface of the first composite measuring support 2 and the center B of the bottom surface of the second composite measuring support 3 as the X-axis, the horizontal direction perpendicular to the X-axis as the Y-axis, and the vertical direction as the Z-axis. S3. When the two structures move relative to each other, read the linear displacement change measured by the linear displacement sensor 15, and the five angular displacements measured by the first angular displacement sensor 16, the second angular displacement sensor 24, the third angular displacement sensor 25, the fourth angular displacement sensor 34, and the fifth angular displacement sensor 35 respectively. S4. Based on spatial geometric relationships and the Euler angular coordinate transformation matrix, using one linear displacement and five angular displacements obtained in step S3, calculate the relative translational displacements between the two structures in the X, Y, and Z directions, as well as the relative rotation angles around the X, Y, and Z axes.
[0038] In the specific operation of step S1, the magnetic grating displacement meter 1 is placed horizontally perpendicular to the direction of the measuring joint, and the first composite measuring support 2 and the second composite measuring support 3 are respectively vertically fixed on the concrete panels on both sides of the measuring joint.
[0039] In the specific operation of step S2, a spatial coordinate system is established, with the center A of the bottom surface of the first composite measuring support 2 as the origin, the line AB connecting the center points of the bottom surfaces of the first composite measuring support 2 and the second composite measuring support 3 as the X-axis direction, the direction of the measuring joint as the Y-axis direction, and the direction perpendicular to the concrete panel as the Z-axis direction.
[0040] In the specific operation of step S3, when the coordinate origin A (0,0,0) remains stationary, due to the relative displacement and torsion between the concrete panels, the center point B (L,0,0) of the base of the second composite measuring support 3 moves to point B'. The single six-degree-of-freedom displacement gauge based on the magnetic grating sensor can measure the distance between points C and D at both ends of the magnetic grating displacement gauge 1 from L to L' through the magnetic grating linear displacement sensor inside the magnetic grating displacement gauge 1. The first angular displacement sensor 16 can measure the angle of rotation of the magnetic grating displacement gauge 1 around its own central axis. The angle of rotation of the magnetic grating displacement gauge 1 around the vertical central axis of the first composite measuring support 2 is measured by the second angular displacement sensor 24 inside the first composite measuring support 2. The third angular displacement sensor 25 measures the rotation angle of the magnetic grating displacement gauge 1 about the horizontal central axis of the first bolt 23 in the vertical direction. The angle of rotation of the magnetic grating displacement gauge 1 around the vertical central axis of the second composite measuring support 3 is measured by the fourth angular displacement sensor 34 inside the second composite measuring support 3. The fifth angular displacement sensor 35 measures the rotation angle of the magnetic grating displacement gauge 1 about the horizontal central axis of the second bolt 33 in the vertical direction. The height of both the first composite measuring support 2 and the second composite measuring support 3 is H. Based on spatial geometry and the Euler angle coordinate transformation matrix, the formula for calculating the coordinates of point B' is as follows:
[0041] Therefore, from the above, we can know that the formulas for calculating the relative displacement of point B in the X, Y, and Z coordinate axes when point B moves to point B' are as follows:
[0042] The above three are the opening and closing degree △X of the measuring seam. B＇ Relative misalignment △Y along the direction of the joint B＇ The relative settlement misalignment △Z of the joint B＇ .
[0043] In step S4, based on the angle changes measured by the five angular displacement sensors, the relative rotation angles of the two plates around the X, Y, and Z coordinate axes can be calculated as follows:
[0044] When the plates on both sides of the joint only have relative translation and no relative torsion in the three axes, due to the linkage of the hinged joints of the two supports, the above formula... ,at this time:
[0045] In other words, when there is only relative translation and no relative torsion between the two structures, the horizontal in-plane angular displacement values measured by the second angular displacement sensor 24 and the fourth angular displacement sensor 34 are equal, the vertical in-plane angular displacement values measured by the third angular displacement sensor 25 and the fifth angular displacement sensor 35 are equal, and the axial torsional angular displacement value measured by the first angular displacement sensor 16 is zero.
[0046] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A single-unit six-degree-of-freedom displacement meter based on a magnetic grating sensor, characterized in that, include: A magnetic grating displacement gauge (1) includes a sleeve (11), a first pull rod (12) and a second pull rod (13) installed inside the sleeve (11), a bracket (14) fixed to the inner wall of the sleeve (11), a linear displacement sensor (15), and a first angular displacement sensor (16). The first pull rod (12) is rotatably connected to one end of the sleeve (11), and the second pull rod (13) is slidably connected to the other end of the sleeve (11). The linear displacement sensor (15) is used to detect the linear displacement of the second pull rod (13) relative to the sleeve (11). The first angular displacement sensor (16) is used to detect the linear displacement of the second pull rod (13) relative to the sleeve (11). The displacement sensor (16) is used to detect the angle of rotation of the first pull rod (12) relative to the sleeve (11) about its axis. The first angular displacement sensor (16) is a magnetic grating type angular displacement sensor, which includes a first magnetic grating disk (161), a first magnetic head and a first detection circuit board (162). The first magnetic grating disk (161) is fixed at the end of the first pull rod (12) located inside the sleeve (11). The first detection circuit board (162) is fixed on the inner wall of the sleeve (11). The first magnetic head is mounted on the first detection circuit board (162) and is arranged opposite to the first magnetic grating disk (161). The first composite measuring support (2) is hinged to the end of the first tie rod (12); And a second composite measuring support (3) hinged to the end of the second tie rod (13); The first composite measuring support (2) is provided with two angular displacement sensors for detecting its relative angular displacement with respect to the first tie rod (12) on a first directional axis and a second directional axis orthogonal to the first directional axis. The first directional axis is parallel to the normal direction of the mounting base surface of the first composite measuring support (2). The first composite measuring support (2) includes a first base (21), a first hinge component (22) rotatable about the vertical axis of the first base (21), a second angular displacement sensor (24), and a third angular displacement sensor (25). The second angular displacement sensor (24) is used to detect the angular displacement of the first hinge component (22) rotating about the vertical axis of the first base (21). The first hinge component (22) is connected to the first tie rod (12) by a first bolt (23), so that the first tie rod (12) can rotate about the first bolt (23). The third angular displacement sensor (25) is used to detect the angular displacement of the first tie rod (12) rotating about the first bolt (23). The second composite measuring support (3) is provided with two angular displacement sensors for detecting its relative angular displacement with respect to the second tie rod (13) on a third directional axis and a fourth directional axis orthogonal to the third directional axis; the third directional axis is parallel to the normal direction of the mounting base surface of the second composite measuring support (3); the second composite measuring support (3) includes a second base (31), a second hinge component (32) rotatable about the vertical axis of the second base (31), a fourth angular displacement sensor (34), and a fifth angular displacement sensor (35); the fourth angular displacement sensor (34) is used to detect the angular displacement of the second hinge component (32) rotating about the vertical axis of the second base (31); the second hinge component (32) is connected to the second tie rod (13) by a second bolt (33), so that the second tie rod (13) can rotate about the second bolt (33); the fifth angular displacement sensor (35) is used to detect the angular displacement of the second tie rod (13) rotating about the second bolt (33); Protective covers (4) are fixed on the side plates of the first hinge component (22) and the second hinge component (32), respectively. The protective covers (4) cover the third angular displacement sensor (25) and the fifth angular displacement sensor (35) inside. A sealing and waterproof component is provided between the protective cover (4) and the corresponding first hinge component (22) or second hinge component (32). The measured values output by the linear displacement sensor (15), the first angular displacement sensor (16), and the four angular displacement sensors installed on the first composite measuring support (2) and the second composite measuring support (3) are used to calculate the six-degree-of-freedom relative pose between the two structures on which the first composite measuring support (2) and the second composite measuring support (3) are installed.
2. The single-unit six-degree-of-freedom displacement meter based on a magnetic grating sensor according to claim 1, characterized in that: The linear displacement sensor (15), the first angular displacement sensor (16), the second angular displacement sensor (24), the third angular displacement sensor (25), the fourth angular displacement sensor (34), and the fifth angular displacement sensor (35) are all magnetic grating sensors.
3. The single-unit six-degree-of-freedom displacement meter based on a magnetic grating sensor according to claim 2, characterized in that: The linear displacement sensor (15) is a magnetic grating linear displacement sensor, which includes a magnetic grating ruler (151), a sixth magnetic head and a sixth detection circuit board (152). The magnetic grating ruler (151) is fixed on the second pull rod (13), the sixth detection circuit board (152) is fixed on the bracket (14), and the sixth magnetic head is mounted on the sixth detection circuit board (152) and is arranged opposite to the magnetic grating ruler (151).
4. The single-unit six-degree-of-freedom displacement meter based on a magnetic grating sensor according to claim 3, characterized in that: The second angular displacement sensor (24) is a magnetic grating type angular displacement sensor, which includes a second magnetic grating disk (241), a second magnetic head, and a second detection circuit board (242). The second magnetic grating disk (241) is fixed to the lower end of the first hinge component (22). The second detection circuit board (242) is installed on the inner wall of the first base (21). The second magnetic head is installed on the second detection circuit board (242) and is arranged opposite to the second magnetic grating disk (241). The third angular displacement sensor (25) is a magnetic grating type angular displacement sensor, which includes a third magnetic grating disk (251), a third magnetic head and a third detection circuit board (252). The third magnetic grating disk (251) is fixed to the end of the first bolt (23), the third detection circuit board (252) is fixed to the side plate of the first hinge component (22), and the third magnetic head is mounted on the third detection circuit board (252) and is arranged opposite to the third magnetic grating disk (251).
5. The single-unit six-degree-of-freedom displacement meter based on a magnetic grating sensor according to claim 4, characterized in that: The fourth angular displacement sensor (34) is a magnetic grating type angular displacement sensor, which includes a fourth magnetic grating disk (341), a fourth magnetic head and a fourth detection circuit board (342). The fourth magnetic grating disk (341) is fixed to the lower end of the second hinge component (32). The fourth detection circuit board (342) is installed on the inner wall of the second base (31). The fourth magnetic head is installed on the fourth detection circuit board (342) and is arranged opposite to the fourth magnetic grating disk (341). The fifth angular displacement sensor (35) is a magnetic grating type angular displacement sensor, which includes a fifth magnetic grating disk (351), a fifth magnetic head and a fifth detection circuit board (352). The fifth magnetic grating disk (351) is fixed to the end of the second bolt (33), the fifth detection circuit board (352) is fixed to the side plate of the second hinge component (32), and the fifth magnetic head is mounted on the fifth detection circuit board (352) and is arranged opposite to the fifth magnetic grating disk (351).
6. A measurement method for a single six-degree-of-freedom displacement gauge based on a magnetic grating sensor as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Arrange the magnetic grating displacement meter (1) horizontally, and fix the first composite measuring support (2) and the second composite measuring support (3) on the two structures to be measured respectively, so that the magnetic grating displacement meter (1) is in a horizontal position in the initial state. S2. Establish a spatial coordinate system with the center A of the bottom surface of the first composite measuring support (2) as the origin, the initial line connecting the center A of the bottom surface of the first composite measuring support (2) and the center B of the bottom surface of the second composite measuring support (3) as the X-axis, the horizontal direction perpendicular to the X-axis as the Y-axis, and the vertical direction as the Z-axis. S3. When the two structures move relative to each other, read the linear displacement change measured by the linear displacement sensor (15) and the five angular displacements measured by the first angular displacement sensor (16), the second angular displacement sensor (24), the third angular displacement sensor (25), the fourth angular displacement sensor (34), and the fifth angular displacement sensor (35). S4. Based on spatial geometric relationships and the Euler angular coordinate transformation matrix, using one linear displacement and five angular displacements obtained in step S3, calculate the relative translational displacements between the two structures in the X, Y, and Z directions, as well as the relative rotation angles around the X, Y, and Z axes.