Alignment device and method
The alignment device uses thermal strain to accurately correlate optical fiber positions with structural positions by applying selective heating or cooling, addressing the challenge of position alignment in optical fiber sensing systems, particularly for large structures.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MIRAIT CORP
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-15
Smart Images
Figure 0007860359000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an alignment device and method thereof for a structure on a monitor in a strain sensing system of a structure using an optical fiber sensor.
Background Art
[0002] An optical fiber sensing system is known in which an optical fiber is fixed along the surface of a structure, and the strain generated in the structure is detected and displayed on a monitor (see, for example, Patent Documents 1 and 2). By injecting light from the end of the optical fiber and analyzing the change in the light that is reflected and returned, it is possible to grasp the position where the change occurred along the optical fiber and the state of the change.
[0003] Such an optical fiber can be laid by being pre-wired in a concrete formwork and integrating the optical fiber cable with the concrete structure when constructing a concrete structure as a structure, by placing the concrete. Also, after constructing the concrete structure, a laying method is adopted in which a groove is formed on the surface of the structure and the optical fiber cable is fixed along the groove (see, for example, Patent Document 3).
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Patent Document 3
Summary of the Invention
Problems to be Solved by the Invention
[0005] Incidentally, while optical fiber sensing systems can display the location along the optical fiber where a change has occurred on a monitor, it is necessary to confirm in advance which location on the structure corresponds to this location. In other words, it is necessary to pre-associate the location along the optical fiber on the monitor with the location on the structure. Generally, such work is performed outdoors and is affected by weather conditions, and especially when sensing large structures such as bridges and tunnels, the range of locations to be confirmed can be quite long.
[0006] The present invention has been made in view of the above circumstances, and its object is to provide a positioning device and method for correlating a position along an optical fiber on a monitor with the position of a structure in a structural strain sensing system using an optical fiber sensor. [Means for solving the problem]
[0007] The alignment device according to the present invention is an alignment device for a structure on a monitor in a structural strain sensing system using an optical fiber sensor, and comprises a main body case, a heat source element having a heat transfer surface that selectively provides heat dissipation or heat absorption by current control, a plate-shaped heat expansion plate having a main surface area larger than the heat transfer surface, and an elastic sheet body that deforms to follow the surface of the structure, wherein the heat expansion plate is fixed so as to close a window hole in the bottom surface of the main body case, the heat source element is located inside the main body case and is fixed to the heat expansion plate so as to make thermal contact with the heat transfer surface along a first main surface of the heat expansion plate facing inward from the main body case, the elastic sheet body is provided on a second main surface of the heat expansion plate facing outward from the main body case, and the alignment device is characterized in that the main body case is pressed against the structure via the elastic sheet body between the heat expansion plate and the structure, thereby selectively applying thermal strain to the pressed area of the elastic sheet body by heating or cooling, and displaying the corresponding position on the monitor.
[0008] With these characteristics, thermal strain can be used to correlate the position along the optical fiber on the strain sensing system's monitor with the position of the structure.
[0009] The above invention may further include a measuring unit for measuring the temperature of the heat expansion plate, and a control unit for controlling the current supplied to the heat source element so that the measured temperature measured by the measuring unit becomes a set temperature. With this feature, the position along the optical fiber on the monitor can be associated with the position of the structure while being automatically controlled by the control unit.
[0010] In the above-described invention, the control unit may be characterized by pre-accepting inputs for two temperatures, a high-temperature side temperature and a low-temperature side temperature, as the set temperature, and then receiving a selection input to select either the high-temperature side temperature or the low-temperature side temperature to start controlling the current to the heat source element. With this feature, the set temperature on the high-temperature side or the low-temperature side can be selected to match the ambient temperature, and the position along the optical fiber on the monitor can be efficiently associated with the position of the structure.
[0011] In the invention described above, the control unit may be characterized by pre-receiving an input of the applied temperature difference as the set temperature, and if the measured temperature is still above zero degrees even when it is lowered by the applied temperature difference, it starts controlling the current to the heat source element to lower the measured temperature by the applied temperature difference. Alternatively, the control unit may be characterized by starting to control the current to the heat source element to raise the measured temperature by the applied temperature difference if it is below zero degrees when the measured temperature is lowered by the applied temperature difference. With such features, the applied temperature difference can be efficiently obtained according to whether the measured temperature is high or low, and the position along the optical fiber on the monitor can be associated with the position of the structure.
[0012] Furthermore, the alignment method according to the present invention is a method for aligning a structure with a monitor in a strain sensing system for a structure using an optical fiber sensor, and includes a main case, a heat source element having a heat transfer surface that selectively provides heat dissipation or heat absorption by current control, a plate-shaped heat expansion plate having a main surface area larger than the heat transfer surface, and an elastic sheet body that deforms to follow the surface of the structure, wherein the heat expansion plate is fixed so as to close a window hole in the bottom surface of the main case, the heat source element is located inside the main case and is fixed to the heat expansion plate so as to make thermal contact with the heat transfer surface along a first main surface of the heat expansion plate facing inward from the main case, and the elastic sheet body is placed on a second main surface of the heat expansion plate facing outward from the main case, and the main case is pressed against the structure via the elastic sheet body between the heat expansion plate and the structure using an alignment device, thereby selectively applying thermal strain to the pressed area of the elastic sheet body by heating or cooling, and displaying the corresponding position on the monitor.
[0013] With these characteristics, thermal strain can be used to correlate the position along the optical fiber on the strain sensing system's monitor with the position of the structure.
[0014] In the above-described invention, the alignment device may further include a measuring unit for measuring the temperature of the heat expansion plate, and a control unit for controlling the current supplied to the heat source element so that the measured temperature measured by the measuring unit becomes a set temperature. With this feature, the position along the optical fiber on the monitor can be automatically controlled by the control unit and associated with the position of the structure.
[0015] In the invention described above, the control unit may be characterized by pre-accepting inputs for two temperatures, a high-temperature side temperature and a low-temperature side temperature, as the set temperature, and then receiving a selection input to select either the high-temperature side temperature or the low-temperature side temperature to start controlling the current to the heat source element. With this feature, the set temperature on the high-temperature side or the low-temperature side can be selected according to the temperature of the structure 54 and the ambient temperature, and the position along the optical fiber on the monitor can be efficiently associated with the position of the structure.
[0016] In the above-described invention, the control unit may be characterized by having an input of the applied temperature difference as the set temperature in advance, and if the measured temperature is still above zero degrees even when it is lowered by the applied temperature difference, it starts controlling the current to the heat source element to lower the measured temperature by the applied temperature difference. Alternatively, the control unit may be characterized by starting to control the current to the heat source element to raise the measured temperature by the applied temperature difference if it is below zero degrees when the measured temperature is lowered by the applied temperature difference. According to this feature, the applied temperature difference can be efficiently obtained according to whether the measured temperature is high or low, and the position along the optical fiber on the monitor can be associated with the position of the structure. [Brief explanation of the drawing]
[0017] [Figure 1] This is a block diagram of a strain sensing system using the alignment device according to the present invention. [Figure 2] This is a perspective view of an alignment device according to one embodiment of the present invention. [Figure 3] This is a cross-sectional view of the main part of the alignment device. [Figure 4] This is a block diagram of the main components of the alignment device. [Modes for carrying out the invention]
[0018] Hereinafter, one embodiment of the alignment apparatus and alignment method according to the present invention will be described with reference to FIGS. 1 to 4.
[0019] First, a strain sensing system of a structure using the alignment apparatus according to this embodiment will be described with reference to FIG. 1.
[0020] As shown in FIG. 1(a), the strain sensing system 50 includes a measuring instrument 51, a monitor 52 connected to the measuring instrument 51 to display a measurement result, and an optical fiber 53 having one end connected to the measuring instrument 51. The optical fiber 53 is fixed to the surface or inside of the structure 54 so as to generate strain following the strain generated in the structure 54. The measuring instrument 51 can, for example, irradiate the optical fiber 53 with pulsed light or the like and measure the backscattering by Brillouin scattered light to measure the strain and temperature change generated in the optical fiber 53. That is, by using the optical fiber 53 as an optical fiber sensor, the strain and temperature of the structure 54 to which the optical fiber 53 is fixed can be measured. Since the measuring instrument used in the strain sensing system and its principle are well-known, further details thereof will be omitted.
[0021] As shown in FIG. 1(b), for example, the strain measured by the measuring instrument 51 is displayed at a position on the monitor 52 corresponding to the position along the optical fiber 53 (distance from the measuring instrument 51). However, the position along the optical fiber installed in the structure 54 and the position on the structure are not clearly corresponding only by installing the optical fiber 53. Therefore, in order to clarify the position on the structure 54 and perform strain measurement, it is necessary to confirm in advance the position along the optical fiber 53 and the corresponding position on the structure 54.
[0022] Therefore, in this embodiment, the alignment device 10 shown below is used to heat or cool specific parts of the optical fiber 53 and the structure 54 to which the optical fiber 53 is attached to generate thermal strain, which is then detected by the strain sensing system 50 to confirm the correspondence between the position along the optical fiber 53 and the specific part on the structure 54. In this case, it is preferable to heat or cool the optical fiber 53, etc., to create a temperature difference of a certain degree or more with respect to the temperature of the structure 54 and the ambient temperature, thereby obtaining a certain degree of thermal strain, which makes it easy to identify the location of the strain displayed on the monitor 52. Furthermore, the alignment device 10 is equipped with a heating / cooling mechanism that can selectively cool or heat, and can switch between heating and cooling according to the ambient temperature, etc.
[0023] More specifically, as shown in Figure 2, the alignment device 10 includes a main body case 1, a heating / cooling mechanism 2, and a battery 3. The front of the main body case 1 is equipped with a display panel 11 that displays the set temperature and other information and also serves as an input device, and the battery 3 is mounted on the back. The battery 3 is preferably a rechargeable battery for power tools, for example, as it allows the use of the battery from a power tool, which is convenient for the worker using the power tool. The top surface of the main body case 1 is equipped with a power switch 12, a changeover switch 13 for switching between heating and cooling of the heating / cooling mechanism, a carrying handle 14, and the like. The handle 14 is positioned to straddle a through-window 15 provided on the top surface of the main body case 1. The sides of the main body case 1 are open, and together with the through-window 15, the heating / cooling mechanism 2 provided on the bottom surface is exposed to the outside air to promote heat exchange.
[0024] Referring also to Figure 3, the heating / cooling mechanism 2 is provided so as to penetrate and close the window hole 4 on the bottom surface of the main body case 1. The heating / cooling mechanism 2 includes a roughly plate-shaped heat source element 21 whose main surface facing outward (downward) of the main body case 1 is the heat transfer surface 21a, a heat expansion plate 22 having a larger main surface area than the heat transfer surface 21a and positioned in contact with the heat transfer surface 21a, an elastic sheet body 23 positioned in contact with the lower surface of the heat expansion plate 22, an insulating section 24 provided to surround the outer periphery of these, and a protective case 25 that protects the outer periphery of the insulating section 24. The heating / cooling mechanism 2 further includes a heat sink 26 positioned in contact with the upper surface of the heat source element 21 and a fan 27 capable of blowing air toward the heat sink 26.
[0025] As described above, the heating / cooling mechanism 2 heats or cools the elastic sheet body 23 pressed against the structure 54 to cause thermal strain in a specific part of the structure 54, including the optical fiber 53. Therefore, the heating / cooling mechanism 2 is designed to be efficiently heated or cooled by the heat source element 21.
[0026] In detail, the heat source element 21 is an element capable of selectively dissipating heat (heating) or absorbing heat (cooling) the heat transfer surface 21a by current control, and for example, a Peltier element can be suitably used. The heat source element 21 has its heat transfer surface 21a (the lower surface on the paper) facing the outside of the main body case 1 in thermal contact with the heat expansion plate 22, and its heat dissipation surface 21b (the upper surface on the paper) facing the inside in thermal contact with the heat sink 26.
[0027] Furthermore, the heat expansion plate 22 is fixed so as to close the window hole 4, and its first main surface 22a facing the inside of the main case 1 is in thermal contact with the heat transfer surface 21a of the heat source element 21. The second main surface 22b of the heat expansion plate 22 facing the outside of the main case 1 is in thermal contact with the elastic sheet body 23. In other words, the heat from the heat source element 21 is expanded by the heat expansion plate 22 to the required area and transferred to the elastic sheet body 23, and the heat is transferred to the structure 54 via the elastic sheet body 23, which is pressed and elastically deforms to follow the shape of the surface of the structure 54. By using the heat expansion plate 22, a relatively wide area can be heated or cooled simultaneously, and the temperature of the pressed area of the alignment device 10 of the structure 54 and the associated thermal strain can be stabilized.
[0028] Typically, it is preferable to reduce power consumption by making the main surface dimensions of the heat source element 21 relatively small, such as 40 x 40 mm, in order to extend the continuous operating time of the alignment device 10 on the battery 3. On the other hand, it is preferable to make the dimensions of the heat expansion plate 22 such as 5 mm thick x 100 mm long x 60 mm wide, so that a relatively large main surface can be heated or cooled at a uniform temperature over a wide area simultaneously. It is preferable to use a material with excellent thermal conductivity for the heat expansion plate 22, and typically copper is used as the material. Furthermore, it is preferable to use a material that is highly elastic and has high thermal conductivity for the elastic sheet body 23, and typically a silicone rubber about 5 mm thick with a high thermal conductivity of about 6 W / mk can be suitably used. The elastic sheet body 23 may also contain materials such as heat transfer fibers that improve the thermal conductivity in the thickness direction (the direction from the inside to the outside of the main case 1: the vertical direction of the paper).
[0029] On the other hand, the heat dissipation surface 21b, which is the main surface of the heat source element 21 facing the heat transfer surface 21a, is in thermal contact with the heat sink 26. The heat sink 26 is equipped with fins 26a that extend radially outward on its outer circumference, and heat exchange can be promoted by airflow from a fan 27 installed above it. This allows for efficient heating of the heat transfer surface 21a and cooling of the heat dissipation surface 21b, or cooling of the heat transfer surface 21a and heating of the heat dissipation surface 21b, by the heat source element 21.
[0030] Furthermore, as described above, the heating / cooling mechanism 2 includes a heat insulating section 24 that covers the outer periphery of a portion of the heat source element 21, the heat expansion plate 22, and the elastic sheet body 23. This is preferable because it suppresses heat leakage from the heat sink 26 to the outer periphery near the surface of the elastic sheet body 23. The heat insulating section 24 is covered on its outer periphery by a protective case 25 to prevent damage. For example, a heat insulating material made of urethane resin can be suitably used as the heat insulating section 24.
[0031] With this alignment device 10, by placing the main case 1 on the structure 54 and pressing it down with its own weight, the pressed area can be heated or cooled via the elastic sheet 23 between the heat expansion plate 22 and the structure 54. In other words, thermal strain can be applied to the area of the structure 54 that is pressed by the elastic sheet 23. This allows the strain sensing system 50 to display the location where strain has occurred on the monitor 52 and to correlate the position along the optical fiber 53 with the position on the structure 54. If multiple optical fibers 53 are installed on the structure, heating or cooling may be performed simultaneously across multiple optical fibers 53.
[0032] In particular, the alignment device 10 can efficiently perform work and align a relatively wide area on the structure 54 simply by being placed on top of the structure 54 and pressing against it. Furthermore, it does not depend on the direction of gravity; for example, it can be pressed against a downward-facing surface from below to deform the structure 54, which also allows for efficient work. In addition, since heating or cooling can be selected, the efficiency of the battery 3 can be increased by selecting heating or cooling according to the temperature of the structure 54 and the ambient temperature, and as a result the battery 3 can be made smaller, and the device can be made significantly smaller.
[0033] As shown in Figure 4, the alignment device 10 preferably includes a measuring unit 31 for measuring the temperature of the heat expansion plate 22 and a control unit 30 for controlling the current supplied to the heat source element 21 based on the temperature measured by the measuring unit 31. For example, the temperature to be applied to the structure 54 is input to the control unit 30 from the display board 11 as a set temperature, and the control unit 30 controls the current supplied to the heat source element 21 so that the temperature measured by the measuring unit 31 becomes the input set temperature. In this way, the temperature of the heat expansion plate 22 can be automatically brought closer to the set temperature, reducing wasted power such as overheating, and allowing the alignment device 10 to be used efficiently.
[0034] It is also preferable to allow the set temperature to be set to two values: a high temperature and a low temperature. In this case, the control unit 30 is configured to accept inputs for both the high temperature and the low temperature in advance, and to receive a selection input to choose which of the high temperature or low temperature to use as the set temperature when the alignment device 10 is in use. The control unit 30 then starts controlling the current to the heat source element 21 after receiving the selection input. This allows the set temperature to be selected from either the high temperature or the low temperature to match the temperature of the structure 54, the temperature of the heat expansion plate 22 to be controlled to achieve a desired temperature difference with the ambient temperature of the structure 54, and efficient alignment can be performed by displaying a distortion of an easily observable size on the monitor 52.
[0035] For example, to create a temperature difference of 20°C or more between the pressing point of the structure 54 and the surrounding area, the high-temperature side is set to 45°C and the low-temperature side to 5°C. Then, if the temperature around the structure 54 (or the ambient temperature assumed to be equivalent) is 25°C or higher, the low-temperature side temperature of 5°C is set as the temperature; if it is less than 25°C, the high-temperature side temperature of 45°C is set as the temperature. This ensures that a temperature difference of 20°C or more can be applied to the heat-expanding plate 22 regardless of the temperature of the structure 54 (or the ambient temperature).
[0036] Alternatively, the temperature difference between the ambient temperature at the pressing point of the structure 54 as described in the above example and the temperature difference applied to the heat-expanding plate 22 may be defined as the applied temperature difference, and the control unit 30 may be configured to accept input of this applied temperature difference in advance, thereby automatically determining the set temperature based on the measured temperature before heating or cooling.
[0037] In this case, for example, if the temperature obtained by subtracting the applied temperature difference from the measured temperature is 0 degrees (°C) or greater, the system controls the measured temperature to be set to that set temperature, using the subtracted temperature as the set temperature. For example, suppose the applied temperature difference is 20°C and the initial measured temperature is 25°C. In this case, the temperature obtained by subtracting is 5°C, which is 0 degrees or greater, so the system controls the measured temperature to be set to 5°C as the set temperature. In other words, the cooling control is performed to set the measured temperature to a temperature that is the initial temperature minus the applied temperature difference.
[0038] On the other hand, if the subtracted temperature is less than zero degrees (°C), the set temperature is set to a value that is equal to the difference in applied temperature from the measured temperature, and the measured temperature is controlled to reach the applied set temperature. For example, suppose the applied temperature difference is 20°C and the initial measured temperature is 15°C. In this case, the subtracted temperature is -5°C, which is less than zero degrees, so the set temperature is set to 35°C, which is the initial measured temperature of 15°C plus the applied temperature of 20°C, and the measured temperature is controlled to reach the applied set temperature. In other words, the heating control is performed so that the measured temperature reaches the set temperature, which is equal to the difference in applied temperature from the initial temperature. By cooling across zero degrees, the large increase in power consumption can be suppressed, and the miniaturization of battery 3 and the device can be achieved.
[0039] In this way, the control unit 30 can automatically set the target temperature up to the required temperature difference, automatically select heating or cooling, and further minimize the power and time required for heating or cooling.
[0040] Although representative embodiments of the present invention and their variations have been described above, the present invention is not necessarily limited thereto and can be modified as appropriate by those skilled in the art. That is, those skilled in the art will be able to find various alternative embodiments and modifications without departing from the scope of the attached claims. [Explanation of Symbols]
[0041] 1. Main unit case 2 Heating / cooling mechanism 10 Alignment device 21 Heat source element 22 Thermal expansion plate 23 Elastic sheet 26 Heatsink 27 Fans
Claims
1. A device for aligning a structure with a monitor in a structural strain sensing system using an optical fiber sensor, The main case and A heat source element having a heat transfer surface that selectively provides heat dissipation or heat absorption by current control, A plate-shaped heat expansion plate having a main surface area larger than the heat transfer surface, The structure includes an elastic sheet body that deforms to conform to the surface of the structure, The heat expansion plate is fixed so as to close the window hole on the bottom surface of the main body case. The heat source element is located inside the main body case and is fixed to the heat expansion plate such that its heat transfer surface is in thermal contact with the first main surface of the heat expansion plate facing inward from the main body case. The elastic sheet body is placed on the second main surface of the thermal expansion plate facing outward from the main body case, A positioning device characterized by pressing the main body case against the structure via the elastic sheet between the heat-expanding plate and the structure, thereby applying thermal strain to the pressing point of the elastic sheet by selecting heating or cooling, and displaying the corresponding position on the monitor.
2. The alignment device according to claim 1, further comprising: a measuring unit for measuring the temperature of the heat expansion plate; and a control unit for controlling the current to the heat source element so that the measured temperature measured by the measuring unit becomes a set temperature.
3. The alignment device according to claim 2, wherein the control unit pre-receives inputs for two temperatures, a high-temperature side temperature and a low-temperature side temperature, as the set temperature, and starts controlling the current to the heat source element upon receiving a selection input to select either the high-temperature side temperature or the low-temperature side temperature.
4. The alignment device according to claim 2, characterized in that the control unit accepts in advance an input of the applied temperature difference as the set temperature, and if the measured temperature is still above zero degrees even when the temperature is lowered by the applied temperature difference, it starts controlling the current to the heat source element to lower the measured temperature by the applied temperature difference.
5. The alignment device according to claim 4, characterized in that the control unit starts controlling the current to the heat source element to raise the measured temperature by the amount of the applied temperature difference when the measured temperature is less than zero degrees.
6. A method for aligning a structure with a monitor in a structural strain sensing system using optical fiber sensors, The main case and A heat source element having a heat transfer surface that selectively provides heat dissipation or heat absorption by current control, A plate-shaped heat expansion plate having a main surface area larger than the heat transfer surface, The structure includes an elastic sheet body that deforms to conform to the surface of the structure, The heat expansion plate is fixed so as to close the window hole on the bottom surface of the main body case. The heat source element is located inside the main body case and is fixed to the heat expansion plate such that its heat transfer surface makes thermal contact with the first main surface of the heat expansion plate facing inward from the main body case, and the elastic sheet body is placed on the second main surface of the heat expansion plate facing outward from the main body case using an alignment device. A positioning method characterized by pressing the main body case against the structure via the elastic sheet between the heat-expanding plate and the structure, thereby applying thermal strain to the pressing point of the elastic sheet by selecting heating or cooling, and displaying the corresponding position on the monitor.
7. The alignment method according to claim 6, further comprising: a measuring unit for measuring the temperature of the heat expansion plate; and a control unit for controlling the current to the heat source element so that the measured temperature measured by the measuring unit becomes a set temperature.
8. The alignment method according to claim 7, characterized in that the control unit pre-receives inputs for two temperatures, a high-temperature side temperature and a low-temperature side temperature, as the set temperature, and starts controlling the current to the heat source element upon receiving a selection input to select either the high-temperature side temperature or the low-temperature side temperature.
9. The alignment method according to claim 7, characterized in that the control unit pre-receives an input of the applied temperature difference as the set temperature, and if the measured temperature is still above zero degrees even when the temperature is lowered by the applied temperature difference, it starts controlling the current to the heat source element to lower the measured temperature by the applied temperature difference.
10. The alignment method according to claim 9, characterized in that the control unit starts controlling the current to the heat source element to raise the measured temperature by the amount of the applied temperature difference when the measured temperature is less than zero degrees.