Measurement device and measurement method

Abstract

Provided is a measurement device capable of measuring a bridge with a simple configuration.　A measurement device 12 for measuring a bridge 1 includes: a movement unit 18 that is attracted to a bridge girder 2 of the bridge by magnetic force and can move in a bridge axis direction along the bridge girder; and a measurement unit 19 that is provided in the movement unit and is for measuring the bridge.

Description

Measuring device and measuring method

[0001] The present invention relates to a measuring device for measuring a bridge and a method for measuring a bridge.

[0002] Methods and devices for checking the degree of deterioration of bridges due to aging or the like are known. For example, Patent Document 1 discloses a non-contact displacement measurement method that uses a non-contact range finder to measure the deflection of a bridge deck. In the non-contact displacement measurement method of Patent Document 1, flat plate targets are first placed on the underside of the deck to be measured and on the undersides of the two main girders that sandwich the deck to be measured. Next, multiple laser range finders placed below the bridge girders measure the distance to the corresponding flat plate targets (the distance from each laser range finder to the corresponding flat plate target). The deflection of the deck is calculated based on the measured distance to each flat plate target.

[0003] Furthermore, Non-Patent Document 1 discloses an observation device for inspecting connecting parts of deck slabs, upper cross beams, gussets, etc. The observation device in Non-Patent Document 1 has traveling units arranged on the lower flanges of adjacent left and right main girders of a bridge, carbon rails connecting the adjacent left and right main girders, and a camera supported by the carbon rails for photographing the part of the bridge girder that is to be observed.

[0004] Patent No. 5984607

[0005] [online], searched on January 17, 2024, Internet (URL: https: / / www.ixs.co.jp / product / 659)

[0006] Incidentally, in addition to checking the degree of deterioration of the bridge as described above, there is a demand for measuring bridges, for example, the height (altitude or relative height) of multiple parts of the bridge girder, the width of the bridge girder, the thickness of the bridge girder, etc. The measurement method described in Patent Document 1 requires repeated work of placing a flat target at the part of the bridge girder that is to be measured, and then, after measurement, removing the placed flat target from the part of the bridge girder that is to be measured, making the work complicated.

[0007] By replacing the camera of the observation device described in Non-Patent Document 1 with a flat target, it is thought that it would be possible to measure bridges, such as the height of multiple parts of the bridge girder. However, with the observation device described in Non-Patent Document 1, in order to support the flat target on the carbon rail, it is necessary to assemble a traveling unit and carbon rails to the main girder of the bridge girder. This makes the device large-scale. There are also other measurement methods that use unmanned aerial vehicles (UAVs) such as drones, but in these cases, the measurement accuracy is relatively low.

[0008] In view of the above background, an object of the present invention is to provide a measurement device and a measurement method that can measure a bridge with a simple configuration.

[0009] In order to solve the above problem, one aspect of the present invention is a measuring device (12, 61, 81) for measuring a bridge (1), which comprises a mobile unit (18) that is attracted to a bridge girder (2) of the bridge by magnetic force and is movable in the bridge axis direction along the bridge girder, and a measuring unit (19, 82) that is provided on the mobile unit and that measures the bridge.

[0010] According to this aspect, the mobile unit is attached to the bridge girder by magnetic force, so there is no need to attach a component to the bridge girder to support the measurement device. Therefore, bridge measurements can be performed with a simple configuration. Furthermore, even if a bridge girder on which a measurement device is placed has multiple measurement positions that are the parts of the bridge to be measured, the measurement unit of the measurement device can be placed at the measurement position simply by moving the mobile unit. Therefore, when there are multiple measurement positions on a bridge, the task of placing the measurement unit of the measurement device at each measurement position is simplified.

[0011] In the above aspect, the moving unit may include a magnet (30) that generates the magnetic force, and a magnet driving mechanism (32) that can change the direction of the magnet.

[0012] According to this aspect, the magnet driving mechanism can change the direction of the magnet, making it possible to overcome steps.

[0013] In the above aspect, the mobile unit may include a base (26) on which the measurement unit is mounted, a plurality of wheels (27) mounted on the base, and a wheel drive mechanism (28) that drives the wheels, and the wheels may be supported on the base without the intervention of elastic elements such as elastic suspensions.

[0014] According to this aspect, the base does not displace or vibrate relative to the wheels, so the measurement unit provided on the base is accurately positioned at the measurement position, thereby improving measurement accuracy.

[0015] In the above aspect, the measurement unit may have a measuring device (41, 87) and a support unit (42) attached to the moving unit and supporting the measuring device, and the support unit may be configured to be extendable and retractable in the vertical direction.

[0016] According to this aspect, if there is an obstacle in the movement direction of the mobile unit or around the measuring instrument placed at the measurement position, contact or interference between the obstacle and the measuring instrument can be suppressed.

[0017] In the above aspect, the measurement unit may have a measurement device (41, 87) and a support unit (86) attached to the moving unit and supporting the measurement device, and the support unit may be configured to be extendable and retractable in the horizontal direction.

[0018] According to this aspect, if there is an obstacle in the movement direction of the mobile unit or around the measuring instrument placed at the measurement position, contact or interference between the obstacle and the measuring instrument can be suppressed.

[0019] In the above aspect, the support unit may have a pair of telescopic bodies (89) that extend and retract on both sides in the horizontal direction, with the measuring device being provided on one of the telescopic bodies and a weight (88) being provided on the other of the telescopic bodies.

[0020] According to this aspect, it is possible to prevent the measurement unit from becoming unbalanced when the support unit is extended or contracted.

[0021] In the above aspect, the measuring instrument may be a reflector (41) for reflecting light emitted from the surveying instrument (16).

[0022] According to this aspect, it is possible to measure the coordinates of the reflector relative to the surveying instrument measured by the surveying instrument. Based on these coordinates and the position of the bridge girder relative to the reflector, it is possible to measure, for example, the height of the bridge girder.

[0023] In the above aspect, the measuring device may be a 3D scanner (87) that acquires three-dimensional point cloud data of the bridge.

[0024] According to this aspect, it is possible to acquire three-dimensional point cloud data of a bridge. An operator can measure the height of a bridge girder by selecting necessary point cloud data from the acquired three-dimensional point cloud data. Even if it is not possible to scan the entire measurement portion of a bridge girder, which is the portion to be measured, in a single scan, it is possible to scan the entire measurement portion by moving the measurement device. Therefore, the task of acquiring three-dimensional point cloud data of the entire measurement portion is facilitated.

[0025] In the above aspect, the measuring device may further include a laser unit (21) provided on the moving unit and configured to irradiate laser light toward the bridge girder.

[0026] According to this aspect, the position of the mobile unit relative to the bridge girder can be confirmed based on the position of the laser light irradiated on the bridge girder.

[0027] In the above aspect, the laser unit may be provided at a position aligned with the reflector in the bridge axis direction.

[0028] According to this aspect, the operator does not need to take into account the misalignment between the laser unit and the reflector in the bridge width direction when moving the mobile unit to the measurement position, which makes it easier to move the mobile unit to the measurement position.

[0029] In the above aspect, the measuring device may further include a camera (62) provided on the mobile unit for photographing the portion of the bridge girder that is hit by the laser light irradiated by the laser unit.

[0030] According to this aspect, even if a worker is working in a position where he or she cannot see the laser light emitted from the laser unit, the worker can confirm the laser light through the image captured by the camera.

[0031] In addition, in order to solve the above-mentioned problems, another aspect of the present invention is a method for measuring a bridge (1), comprising the steps of: preparing a measuring device (12, 61, 81) having a mobile unit (18) that is attracted to a bridge girder (2) of the bridge by magnetic force and a measuring unit (19, 82) that is attached to the mobile unit and that measures the bridge; an arrangement step of attracting the measuring device to the bridge girder of the bridge to be measured and moving the mobile unit along the bridge girder in the bridge axis direction to place the measuring unit at a predetermined measurement position; and a measurement step of measuring the bridge using the measuring unit at the measurement position.

[0032] According to this aspect, since the mobile unit is attached to the bridge girder by magnetic force, there is no need to attach a component to the bridge girder to support the measurement device. Therefore, the measurement unit can be simply attached to the bridge girder. Furthermore, the measurement unit can be placed at the measurement position simply by moving the mobile unit. Therefore, if there are multiple measurement positions on a bridge, the measurement unit of the measurement device can be easily placed at each measurement position.

[0033] The present invention can provide a measurement device and a measurement method that can measure a bridge with a simple configuration.

[0034] a perspective view showing an example of a bridge girder to which the measuring device according to the present invention is applied; a diagram showing a measurement system including the measuring device according to the first embodiment; a perspective view showing the measuring device according to the first embodiment; a perspective view showing the measuring device according to the first embodiment turned upside down; a side view (A) showing a state in which a support unit of the measuring device according to the first embodiment is shortened, and a side view (B) showing this support unit in an extended state; a block diagram of the measuring device and operation terminal according to the first embodiment; a perspective view showing a state in which the measuring device according to the first embodiment is arranged on the underside of the main girder of a bridge girder; a perspective view showing a state in which a measuring device according to a modified example of the first embodiment is arranged on the underside of the main girder of a bridge girder; a side view showing the measuring device according to the second embodiment; a diagram showing a measurement system including the measuring device according to the second embodiment; a side view (A) showing a state in which a support unit of the measuring device according to the third embodiment is shortened, and a side view (B) showing this support unit in an extended state;

[0035] First Embodiment Hereinafter, a measurement system 10 including a measurement device 12 for measuring a bridge 1 according to the present invention will be described with reference to the drawings.

[0036] As shown in FIG. 1 , a bridge 1 includes a bridge girder 2 supported by abutments or piers (not shown). The bridge girder 2 includes multiple main girders 3 extending in the bridge axis direction, counter-tilt structures 4 and cross structures 5 (lower cross structures, see FIG. 2 ) connecting adjacent main girders 3, a deck 6 provided on the main girders 3, a pavement layer 7 provided on the deck slab 6, and a protective fence 8. In this embodiment, each main girder 3 is an I-beam. The lower surfaces of the counter-tilt structures 4 and the cross structures 5 are located above the lower surfaces of each main girder 3. In other embodiments, the bridge girder 2 may be a box girder bridge or a corrugated steel web bridge.

[0037] Due to deterioration over time, etc., work may be performed to replace the existing deck 6 with a new precast deck 6. In this case, a gap is formed between the main girder 3 and the new precast deck 6 to match the height of the top surface of the new precast deck 6. A sealant (not shown) and a filler (not shown), such as concrete or non-shrink mortar, are provided in this gap. In order to manage and adjust this gap (separation distance), there is a need to measure the separation distance based on the height of the bridge girder 2 and the thickness of the new precast deck slab. Therefore, in this embodiment, the height of the underside of the bridge girder 2, including the underside of the counter-bracing structure 4, the underside of the cross strut 5, and the underside of the main girder 3, is measured using the measurement system 10.

[0038] 2, the measurement system 10 includes a measuring device 12 placed on the main girder 3 of the bridge girder 2, an operation terminal 14 configured to be able to communicate with the measuring device 12 and to receive operations from an operator, and a surveying instrument 16 capable of measuring at least the height of the measuring device 12. In this embodiment, the surveying instrument 16 is a total station that can measure the position and height of the measuring device 12 by irradiating light toward the measuring device 12 and calculating the distance from the reflected light.

[0039] 3 and 4 , the measurement device 12 has a mobile unit 18 that is magnetically attached to the main girder 3 of the bridge girder 2 and is movable along the main girder 3, and a measurement unit 19 that is provided on the mobile unit 18 and that measures the height of the bridge girder 2. The measurement device 12 also has a first camera 20 that is provided on the mobile unit 18 and that takes pictures of the surroundings of the mobile unit 18, and a laser unit 21 (see FIG. 4 ) that is provided on the mobile unit 18 and that irradiates laser light toward the bridge girder 2. Furthermore, the measurement device 12 has a plurality of control units 22A, 22B (see FIG. 3 ) that are provided on the mobile unit 18 and that perform various controls of the measurement device 12.

[0040] The moving unit 18 adheres to the underside of one of the main girders 3. The moving unit 18 has two moving bodies 23A and 23B arranged at a distance from each other in the left-right direction, and a connecting member 24 that connects the moving bodies 23A and 23B. Because the two moving bodies 23A and 23B have the same configuration, only one of the moving bodies 23A will be described below, and a description of the other moving body 23B will be omitted.

[0041] As shown in FIG. 3 , the mobile body 23A includes a base 26, a plurality of wheels 27 mounted on the lower portion of the base 26, and corresponding wheel drive mechanisms 28 mounted on the base 26 for rotating each wheel 27. The base 26 has, for example, a rectangular shape elongated in the front-to-rear direction (the bridge axis direction, i.e., the direction of movement) in a plan view. The wheels 27 are supported on the base 26 without any elastic suspension. The mobile body 23A may be an electric vehicle of a known configuration in which each wheel 27 travels while being magnetically attached to the main girder 3. The mobile body 23A includes a shaft 29 rotatably supported on each wheel 27, a plurality of permanent magnets 30 arranged within each wheel 27, a magnet holder 31 supported on each shaft 29 and holding the permanent magnets 30, and a magnet drive mechanism 32 for rotating the shaft 29. The mobile body 23A also includes a box 34 covering the upper portion of the base 26. A protruding piece 35 that protrudes downward is provided on the lower part of the base 26. The protruding piece 35 is provided on the other of the left and right side parts of the base 26, on the side of the moving body 23B.

[0042] Each wheel 27 is provided at the front and rear of the base 26. Each wheel 27 has a contact body 37 that can come into contact with the underside of the bridge girder 2, and a pair of flat plates 38 that are arranged on both the left and right sides (both sides in the bridge width direction) of the contact body 37. The contact body 37 has a shape in which both the left and right sides (both sides in the bridge width direction) of a hollow spherical member are cut out. Each flat plate 38 is arranged so as to cover the opening of the contact body 37 formed by the cutout. One of the flat plates 38 has a through hole (not shown) that penetrates in the direction of the rotation axis of the corresponding wheel 27.

[0043] Each wheel drive mechanism 28 has an electric motor (not shown) and a rotating shaft (not shown) connected to the output shaft of the electric motor with or without a speed reducer. Each rotating shaft extends along the rotation axis of the corresponding wheel 27. One end of each rotating shaft is connected to the outer surface of the other flat plate 38 of the corresponding wheel 27. Each wheel drive mechanism 28 generates driving force for rotating the corresponding wheel 27 via the rotating shaft.

[0044] Each shaft 29 extends along the rotation axis of the corresponding wheel 27. A portion of each shaft 29 passes through a through-hole (not shown) in one flat plate 38 of the corresponding wheel 27 and is disposed inside the corresponding wheel 27. Each shaft 29 is rotatably supported by the corresponding wheel 27 by a bearing (not shown) provided in the through-hole in one flat plate 38 of the corresponding wheel 27 and a bearing (not shown) provided on the inner surface of the other flat plate 38 of the corresponding wheel 27.

[0045] The magnet holder 31 is fixed to the shaft 29 and is rotatable together with the shaft 29. The base end of the magnet holder 31 extends from the shaft 29 toward the outside in the radial direction of the rotation axis of the corresponding wheel 27. The tip end of the magnet holder 31 extends in a circumferential direction intersecting the rotation axis of the corresponding wheel 27 and forms a fan shape along the inner surface of the contact body 37 of the corresponding wheel 27. Each permanent magnet 30 is disposed at the tip end of the magnet holder 31. The multiple permanent magnets 30 are disposed at intervals from one another along the extension direction of the tip end of the magnet holder 31. Each permanent magnet 30 may be, for example, a neodymium magnet.

[0046] Each magnet drive mechanism 32 may be, for example, a servo motor with a servo function. Each magnet drive mechanism 32 is provided on the end of the corresponding shaft 29, which is on the flat plate 38 side of the corresponding wheel 27. Each magnet drive mechanism 32 generates a drive force for rotating the corresponding shaft 29 and magnet holder 31 around the rotation axis of the corresponding wheel 27. By rotating the corresponding shaft 29 and magnet holder 31, the magnet drive mechanism 32 changes the orientation of the permanent magnet 30 (the orientation relative to the rotation axis of the wheel 27). The magnet drive mechanism 32 may actively change the orientation of the permanent magnet 30 as described above, and may also be rotatable by a magnetic force acting on the permanent magnet 30. This operation is achieved by using a servo motor that can be rotated by a moment acting on the output shaft (i.e., a backdrive servo motor) or by torque control of the servo motor. In this manner, the permanent magnet 30 passively rotates due to the magnetic force acting between the permanent magnet 30 and the running path, and the permanent magnet 30 faces in the direction where the magnetic force is strongest. As a result, when the road is not flat but has uneven or curved surfaces, the direction of the permanent magnet 30 is passively adjusted to face the contact point of each wheel 27, and the permanent magnet 30 can be maintained in an adhering state to the road.

[0047] In this embodiment, the connecting member 24 connecting the two moving bodies 23A and 23B to each other is a shaft extending in the left-right direction (bridge width direction). Each of the left and right ends of the connecting member 24 is coupled to a protrusion 35 of the corresponding moving body 23A or 23B via a bearing. This allows the two moving bodies 23A and 23B to rotate relative to each other, allowing four or more wheels 27 to contact the road even on uneven or curved roads. In other words, the rotation mechanism of the two moving bodies 23A and 23B, consisting of the connecting member 24 and bearings, provides an inelastic suspension function. As described above, the adjustment of the direction of the permanent magnet 30 by the magnet drive mechanism 32 and the inelastic suspension provided by the connecting member 24 enable four or more wheels 27 to maintain contact and adhesion on uneven or curved roads. Wheeled robots and crawler robots without these mechanisms would experience detachment of the wheels 27 or parts of the tracks from the road and lift up on uneven or curved roads. As a result, not only will the required driving force for travel not be exerted, but if magnets are built into the wheels 27 or tracks, the magnetic force for adhering to the road will be reduced, creating the risk of them falling off.

[0048] The measurement unit 19 is provided on the box 34 of the mobile body 23A, one of the two mobile bodies 23A, 23B. The measurement unit 19 has a 360° prism 41 for measuring the height of the bridge girder 2 in cooperation with the surveying instrument 16, and a support unit 42 (see FIG. 5) attached to the mobile unit 18 and supporting the 360° prism 41.

[0049] The 360° prism 41 is a reflecting material for reflecting light emitted from the surveying instrument 16, and is formed, for example, by combining multiple triangular pyramid-shaped prisms in a radial pattern. Instead of using the 360° prism 41 as a reflecting material, a flat target may be used.

[0050] As shown in FIG. 5 , the support unit 42 is configured to be extendable and retractable in the vertical direction. The support unit 42 may have, for example, a known configuration including multiple cylindrical bodies 43A, 43B, and 43C connected to one another in a telescopic fashion, which are electrically driven to extend and retract. In one example, a flexible rack gear 44 is fixed to the innermost cylindrical body 43A of the multiple cylindrical bodies 43A, 43B, and 43C. A pinion gear 45 meshing with the rack gear 44 is rotated by an electric motor 46. The rack gear 44 is wound up by a drum 47 when the support unit 42 is retracted. The 360° prism 41 is fixed to the innermost cylindrical body 43A of the multiple cylindrical bodies 43A, 43B, and 43C of the support unit 42.

[0051] The multiple cylindrical bodies 43A, 43B, 43C, which are connected in a telescopic manner, extend in the vertical direction. The support unit 42 is retracted by driving the electric motor 46 so that the pinion gear 45 rotates in a direction that winds the rack gear 44 onto the drum 47 (see FIG. 5A). The support unit 42 is extended by driving the electric motor 46 so that the pinion gear 45 rotates in a direction that extends the rack gear 44 wound onto the drum 47 (see FIG. 5B). In other embodiments, the support unit 42 may be provided to be extendable and contractible using a ball spline, a chain block, a hydraulic cylinder, an air cylinder, or the like.

[0052] 3 and 4 , the first camera 20 captures an image in front of the mobile unit 18. The first camera 20 is disposed between two mobile bodies 23A and 23B. The first camera 20 may be, for example, a known complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD). In another embodiment, the measurement device 12 may be provided with two first cameras 20 to capture images in front and behind the mobile unit 18.

[0053] As shown in Fig. 4, the laser unit 21 is provided on one of the moving bodies 23A. More specifically, the laser unit 21 is provided at a position aligned with the 360° prism 41 in the front-to-rear direction. The laser unit 21 is disposed inside the box body 34 of the one of the moving bodies 23A so as to irradiate laser light downward from the one of the moving bodies 23A. In this embodiment, the laser unit 21 is configured to irradiate a linear laser light.

[0054] Each of the multiple control units 22A, 22B is an electronic control unit (ECU) including a CPU, a non-volatile memory (ROM), a volatile memory (RAM), etc. Each control unit 22 executes various controls of the measurement device 12 by executing arithmetic processing according to a program using the CPU. Each control unit 22A, 22B may be configured as a single piece of hardware, or may be configured as a unit consisting of multiple pieces of hardware. In this embodiment, the measurement device 12 has two control units 22A, 22B. Each control unit 22A, 22B is disposed on the base 26 of the corresponding mobile body 23A, 23B of the mobile unit 18, more specifically, inside the box 34 of the mobile body 23A, 23B. In this embodiment, as shown in FIG. 6 , one control unit 22A is connected to the wheel drive mechanism 28 and magnet drive mechanism 32 of the corresponding mobile body 23A, the electric motor 46 of the support unit 42, the first camera 20, and the laser unit 21. The other control unit 22B is connected to the wheel drive mechanism 28 and magnet drive mechanism 32 of the corresponding moving body 23B. The two control units 22A and 22B are capable of communicating with each other via a harness (not shown).

[0055] As shown in Fig. 2, in this embodiment, the operation terminal 14 is a notebook personal computer. As also shown in Fig. 6, the operation terminal 14 has a computing unit 51, a keyboard 52 connected to the computing unit 51, and a display 53 connected to the computing unit 51. Predetermined applications are installed in the operation terminal 14 in advance.

[0056] The arithmetic unit 51 is an electronic control unit (ECU) including a CPU, a non-volatile memory (ROM), a volatile memory (RAM), etc. The arithmetic unit 51 executes arithmetic processing according to a program using the CPU. The arithmetic unit 51 may be configured as a single piece of hardware, or may be configured as a unit consisting of multiple pieces of hardware.

[0057] The control units 22A, 22B of the measuring device 12 and the arithmetic unit 51 of the operation terminal 14 are configured to be able to communicate with each other. The control units 22A, 22B of the measuring device 12 and the arithmetic unit 51 of the operation terminal 14 transmit and receive data or signals to and from each other, for example, via Bluetooth (registered trademark), which is a short-range wireless communication standard.

[0058] The keyboard 52 is an input unit for receiving operations from the operator. The arithmetic unit 51 of the operation terminal 14 generates signals for various control operations of the measuring device 12 based on, for example, input keys and transmits these signals to the control units 22A and 22B of the measuring device 12. The control units 22A and 22B of the measuring device 12 execute various controls of the measuring device 12 based on the received signals. For example, the control units 22A and 22B of the measuring device 12 execute control to move the mobile unit 18 by driving the wheel drive mechanisms 28 of the corresponding mobile bodies 23A and 23B. At this time, the control units 22A and 22B may calculate a prediction line that predicts the movement direction of the mobile unit 18 based on the wheel speed difference between the two mobile bodies 23A and 23B. Furthermore, one of the control units 22A executes control to extend and retract the support unit 42 by driving the electric motor 46 of the support unit 42. Furthermore, one control unit 22A operates the laser unit 21 to control the laser unit 21 to emit laser light.

[0059] It should be noted that the control for extending and retracting the support unit 42 is preferably configured so that the worker can grasp the vertical length of the support unit 42. For example, the worker may input the vertical length of the support unit 42 into the keyboard 52, and one control unit 22A may execute control for extending and retracting the support unit 42 based on the input length.

[0060] The display 53 is an output unit for displaying various data received from each of the control units 22A and 22B. For example, the display 53 displays an image (including video) captured by the first camera 20. At this time, the display 53 may display a prediction line superimposed on the image captured by the first camera 20.

[0061] In another embodiment, the operation terminal 14 may be a tablet-type terminal configured with a touch panel having a screen.

[0062] A method for measuring the height of the underside of the bridge girder 2 using the measurement system 10 configured as above will be described.

[0063] First, the worker places the previously prepared measuring device 12 on the underside of one of the main girders 3. Specifically, the worker drives the magnet drive mechanisms 32 of the movable bodies 23A and 23B of the mobile unit 18 via the operation terminal 14, rotating the shafts 29 and magnet holders 31 so that the permanent magnets 30 face the underside of the main girder 3. Then, the worker brings the contact bodies 37 of the wheels 27 of the movable bodies 23A and 23B of the mobile unit 18 into contact with the underside of the main girder 3. As a result, the outer surfaces of the contact bodies 37 of the wheels 27 of the movable bodies 23A and 23B of the mobile unit 18 that face the permanent magnets 30 are attracted to the underside of the main girder 3. In this way, the measuring device 12 is placed on the underside of the main girder 3. At this time, the measuring device 12 is placed on the underside of the main girder 3 so that the fore-and-aft direction of the movable bodies 23A and 23B coincides with the extension direction (bridge axis direction) of the main girder 3. This allows the measuring device 12 to move in the bridge axis direction.

[0064] Next, the worker places the measuring device 12 at the measurement position, which is the measurement target portion of the underside of the main girder 3 (placement process). Specifically, the worker operates the operation terminal 14 to activate the wheel drive mechanisms 28 of each moving body 23A, 23B of the mobile unit 18, and moves the measuring device 12 along the extension direction of the main girder 3 (bridge axis direction). At this time, the display 53 of the operation terminal 14 may display an image captured by the first camera 20. The worker may operate the operation terminal 14 while checking the image of the first camera 20 displayed on the display 53. The worker may also move the measuring device 12 with the support unit 42 retracted to its minimum length. This prevents contact between the obstacle and the 360° prism 41 of the measurement unit 19 if there is an obstacle in the direction of movement of the mobile unit 18. If there is a step on the path of the wheel 27, when the wheel 27 comes into contact with both the path and the step, the operator operates the operation terminal 14 to activate the magnet drive mechanism 32 of the moving unit 18, changing the direction of the permanent magnet 30, which was facing the path so as to exert a magnetic force on the path, to face the step. This causes the wheel 27 to move away from the path and be attracted to the step. In this way, the wheel 27 can climb up the step and travel. By similarly changing the direction of the permanent magnets 30 for the other wheels 27, it becomes possible for the measuring device 12 to climb over the step. If the shape and arrangement of the step are known, such as bolts arranged consecutively at regular intervals, the direction of the permanent magnets 30 may be automatically changed by a program.

[0065] Furthermore, as shown in FIG. 7 , the worker may operate the laser unit 21 as appropriate by operating the operation terminal 14. The laser light from the laser unit 21 is directed toward the underside of the main girder 3. This allows the worker to confirm the position of the measuring device 12 relative to the main girder 3 based on the position of the laser light directed toward the underside of the main girder 3. Because the laser unit 21 is aligned with the 360° prism 41 in the fore-and-aft direction, the worker does not need to move the measuring device 12 to the measurement position while taking into account any misalignment between the laser unit 21 and the 360° prism 41 in the fore-and-aft direction (bridge axis direction) or the left-and-right direction (bridge width direction). This makes it easier to move the measuring device 12 to the measurement position.

[0066] Next, as shown in Figure 2, the operator measures the position (coordinates) of the 360° prism 41 relative to the surveying instrument 16 by irradiating light from the surveying instrument 16 placed on the ground toward the 360° prism 41 (measurement step). Here, the coordinates may be three-dimensional coordinates including orthogonal X and Y coordinates on a horizontal plane and elevation (vertical coordinates), or may be just elevation or height relative to a predetermined reference point.

[0067] At this time, the operator may operate the operation terminal 14 to appropriately extend the support unit 42 to position the 360° prism 41 lower. This suppresses interference between the obstacle and the light emitted from the surveying instrument 16 if there is an obstacle between the measurement position and the surveying instrument 16. As described above, the wheels 27 are supported on the base 26 without any elastic suspension. Therefore, the base 26 does not displace or vibrate relative to the wheels 27. Furthermore, the measurement unit 19 is also fixed to the base 26 without any elastic element. In this way, the measurement device 12, the base 26, and the wheels 27 are connected in such a manner that the measurement unit 19 does not vibrate during travel. This allows the measurement unit 19 mounted on the base 26 to be accurately positioned at the measurement position, improving measurement accuracy.

[0068] Next, the worker calculates the height of the underside of the main girder 3 of the bridge girder 2 at the measurement position based on the coordinates of the 360° prism 41 relative to the surveying instrument 16, the vertical dimension of the moving unit 18, and the vertical length of the support unit 42. In this way, the height of the underside of the main girder 3 is measured.

[0069] The worker can calculate the height of the top surface of the main girder 3 by adding the vertical dimension of the main girder 3 to the height of the bottom surface of the main girder 3 calculated above. The worker can calculate the separation distance based on the height of the top surface of the main girder 3 and the thickness of the new precast deck slab.

[0070] Because the measuring device 12 is attached to the main girder 3 of the bridge girder 2 by magnetic force, the worker does not need to attach a component to the main girder 3 of the bridge girder 2 to support the measuring device 12. Therefore, the bridge 1 can be measured with a simple configuration. Furthermore, the measuring device 12 can move along the extension direction (bridge axis direction) of the main girder 3 of the bridge girder 2 while attached to the main girder 3 of the bridge girder 2. Therefore, even if there are multiple measurement positions for the bridge 1 on the main girder 3 of the bridge girder 2 on which the measuring device 12 is placed, the worker can place the measuring device 12 at the measurement position simply by operating the operation terminal 14 and moving the measuring device 12. Therefore, when there are multiple measurement positions on the main girder 3 of the bridge girder 2, the worker can easily place the measuring device 12 at each position.

[0071] The position at which the laser unit 21 is provided may be changed. For example, as shown in Fig. 8, the laser unit 21 is provided at a position shifted outward in the left-right direction (bridge width direction) from the 360° prism 41, more specifically, on the outer left-right side of the box body 34 of one of the moving bodies 23A.

[0072] When the measuring device 12 is placed on the underside of the main girder 3, the laser light from the laser unit 21 is irradiated toward the underside of the counter-tilting structure 4 or the underside of the cross-bracing structure 5. Because the undersides of the counter-tilting structure 4 and the cross-bracing structure 5 are located higher than the undersides of the main girders 3, a step is formed between the measuring device 12 placed on the underside of the main girder 3 and the undersides of the counter-tilting structure 4 and the cross-bracing structure 5. By irradiating the laser light from the laser unit 21 toward the underside of the counter-tilting structure 4 or the underside of the cross-bracing structure 5, the worker can easily confirm the position of the measuring device 12 relative to the counter-tilting structure 4 and the cross-bracing structure 5.

[0073] Second Embodiment Next, a second embodiment of a measurement system 60 including a measurement device 61 of the present invention will be described with reference to Figures 9 and 10. Elements that are the same as or similar to those in the measurement system 10 including the measurement device 12 of the first embodiment are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0074] As shown in Figure 9, the measuring device 61 further includes a second camera 62 that photographs the portion of the bridge girder 2 that is hit by the laser light irradiated by the laser unit 21, and a support member 63 that is provided on the mobile unit 18 and supports the second camera 62.

[0075] In this embodiment, the support member 63 is a rod-shaped member. The support member 63 may be made of, for example, metal. One end of the support member 63 may be coupled to the box body 34 of one of the moving bodies 23A of the moving unit 18. The other end of the support member 63 is provided with a second camera 62. Like the first camera 20, the second camera 62 may be, for example, a known CMOS image sensor or CCD. The second camera 62 is connected to one of the control units 22A of the measurement device 61.

[0076] 10 , the display 53 displays the image captured by the second camera 62. This allows the worker to check the laser light through the image captured by the second camera 62 even if the worker is performing work (e.g., operating the operation terminal 14) in a position (e.g., on top of the bridge girder 2) where the laser light emitted from the laser unit 21 cannot be seen.

[0077] Third Embodiment Next, a measurement system 80 including a measurement device 81 of the present invention will be described with reference to Fig. 11. Unlike the measurement system 10 including the measurement device 12 of the first embodiment, the measurement system 80 including the measurement device 81 according to the third embodiment does not have a surveying instrument 16. Furthermore, the measurement device 81 according to the third embodiment differs from the measurement device 12 of the first embodiment in the configuration of the measurement unit 82. Components similar to those of the measurement device 12 according to the first embodiment are assigned the same reference numerals, and descriptions thereof will be omitted.

[0078] The measurement unit 82 extends in the vertical direction and has a fixed member 85 fixed to the moving unit 18, a support unit 86 extending in the front-to-back direction (horizontal direction) of the moving unit 18, and a 3D scanner 87 and a weight 88 provided on the support unit 86.

[0079] In this embodiment, the fixed member 85 is a tubular member extending in the vertical direction. The fixed member 85 may be made of, for example, metal. One end of the fixed member 85 is fixed to the box body 34 of one of the movable bodies 23A of the moving unit 18. In other embodiments, the measurement unit 82 may not have the fixed member 85, and the support unit 86 may be attached to the box body 34 of one of the movable bodies 23A of the moving unit 18.

[0080] The support unit 86 may have, for example, a pair of telescopic bodies 89 formed by connecting multiple cylindrical bodies 89A, 89B, and 89C in a telescopic manner, which may be electrically driven to extend and retract. In one example, a pair of flexible rack gears (not shown) is fixed to the innermost cylindrical body 89A of the multiple cylindrical bodies 89A, 89B, and 89C of each telescopic body 89. Pinion gears (not shown) meshing with the rack gears are rotated by an electric motor 90. When the support unit 86 is retracted, the rack gears are wound by a pair of drums (not shown). The 3D scanner 87 is attached to the innermost cylindrical body 89A of one of the multiple cylindrical bodies 89A, 89B, and 89C. The weight 88 is attached to the innermost cylindrical body 89A of the other of the multiple cylindrical bodies 89A, 89B, and 89C.

[0081] The support unit 86 is configured as described above to be extendable in the front-to-rear direction (horizontal direction). Specifically, one of the plurality of cylinders 89A, 89B, 89C extends toward the rear of the mobile unit 18. When one of the plurality of cylinders 89A, 89B, 89C is fully extended, the innermost cylinder 89A of the one of the plurality of cylinders 89A, 89B, 89C is preferably located outward (rearward) from the mobile unit 18. The other of the plurality of cylinders 89A, 89B, 89C extends toward the front of the mobile unit 18. In another embodiment, the support unit 86 may be attached to the fixing member 85 so as to be extendable in the left-to-right direction (bridge width direction).

[0082] The 3D scanner 87 may have a known configuration, for example, including an illumination unit (not shown) that illuminates light toward surrounding objects within a predetermined scanning range and a light-receiving unit (not shown) that receives the reflected light from the illumination unit when the light is reflected by the surrounding objects. The 3D scanner 87 acquires three-dimensional point cloud data of surrounding objects based on the time from when the illumination unit illuminates light until the illuminated light is reflected by the surrounding objects and received by the light-receiving unit, as well as the light detection angle. In this embodiment, the 3D scanner 87 acquires three-dimensional point cloud data of the lower part of the bridge girder 2, including at least the underside of the deck 6 of the bridge girder 2 and the underside of the bridge girder 2.

[0083] To acquire three-dimensional point cloud data of the lower part of the bridge girder 2, first, the worker places the measuring device 81 on the underside of the main girder 3 of the bridge girder 2 using the same method as in the first embodiment. If necessary, the worker may move the measuring device 81 to a predetermined position on the underside of the main girder 3 using the same method as in the first embodiment. Next, the worker directs the 3D scanner 87 toward the lower part of the bridge girder 2 to scan. This allows the worker to acquire three-dimensional point cloud data of the lower part of the bridge girder 2. The worker can measure the height of the lower surface of the main girder 3 or the height of the upper surface of the main girder 3 by selecting the necessary point cloud data from the acquired three-dimensional point cloud data.

[0084] The worker may operate the operation terminal 14 to move the measuring device 81 to another predetermined position on the main girder 3, and then have the 3D scanner 87 scan again toward the lower part of the bridge girder 2. This makes it possible to scan the entire measurement portion, which is the portion of the lower part of the bridge girder 2 to be measured, by moving the measuring device 81, even if it is not possible to scan the entire measurement portion, which is the portion to be measured, in a single scan. This therefore facilitates the task of acquiring three-dimensional point cloud data for the entire measurement portion.

[0085] When moving the measuring device 81, the worker can operate the operation terminal 14 to shorten the support unit 86 to its minimum length (see FIG. 11(A)). This prevents contact between the obstacle and the 3D scanner 87 of the measuring unit 82 if there is an obstacle in the direction of movement of the mobile unit 18. When scanning the lower part of the bridge girder 2, the worker can operate the operation terminal 14 to extend the support unit 86 to its maximum length (see FIG. 11(B)). This allows the 3D scanner 87 to scan the lower part of the bridge girder 2 while avoiding the mobile unit 18. In other words, interference between the mobile unit 18 and the light emitted from the 3D scanner 87 is reduced.

[0086] When one of the plurality of cylindrical bodies 89A, 89B, and 89C on which the 3D scanner 87 is mounted is extended, the position of the center of gravity of the measuring device 81 shifts rearward, which may result in variations in the load acting on the wheels 27 of each moving body 23A, 23B of the moving unit 18. Therefore, by providing weights 88 to the other of the plurality of cylindrical bodies 89A, 89B, and 89C and extending the other of the plurality of cylindrical bodies 89A, 89B, and 89C together with the one of the plurality of cylindrical bodies 89A, 89B, and 89C, the shift in the position of the center of gravity of the measuring device 81 is suppressed. In other words, the measurement unit 82 is prevented from losing balance when the support unit 86 is extended or retracted. Note that there is no limit to the maximum length of the other of the plurality of cylindrical bodies 89A, 89B, and 89C on which the weights 88 are mounted when fully extended. By appropriately selecting the weight of the weight 88, the maximum length of the other of the multiple cylindrical bodies 89A, 89B, 89C may be equal to or less than the maximum length of one of the multiple cylindrical bodies 89A, 89B, 89C, or may be longer than the maximum length of one of the multiple cylindrical bodies 89A, 89B, 89C.

[0087] Although the description of the specific embodiment has been completed above, the present invention is not limited to the above embodiment and can be widely modified and implemented. For example, in the above embodiment, the moving unit 18 of the measuring device 12 is attached to the underside of the main girder 3 (I-beam) by magnetic force, but if the web of a box girder bridge is made of steel (e.g., a corrugated steel plate web), the moving unit 18 of the measuring device 12 may be attached to the web. Furthermore, the bridge 1 may be a concrete bridge as long as the moving unit 18 can be attached by magnetic force.

[0088] The measuring device 12 of the first embodiment may have an inclination sensor that detects the inclination angle of the moving unit 18 with respect to the horizontal plane. This makes it possible to correct the deviation between the position of the laser light emitted from the laser unit 21 and the position of a measuring device such as the 360° prism 41 or the 3D scanner 87, taking into account, for example, the longitudinal gradient. Therefore, the position of the measuring device such as the 360° prism 41 or the 3D scanner 87 can be brought closer to the measurement position with high accuracy.

[0089] The 3D scanner 87 of the third embodiment may be provided in the support unit 42 of the first embodiment, and the 360° prism 41 of the first embodiment may be provided in the support unit 86 of the third embodiment. Also, the support unit 42 of the first embodiment may be used instead of the fixing member 85 of the third embodiment.

[0090] A net may be placed under the main girder 3. The net may impede measurement by, for example, obstructing the progress of the mobile unit 18. Therefore, the measurement device 12 may have a cutter as an obstacle removal device for removing the net, which is an obstacle. The cutter may be fixed to the mobile unit 18 so as to be positioned at a predetermined position on the measurement device 12, or may be movably mounted on the mobile unit 18 and operated via the operation terminal 14. The cutter may also be configured to have a fixed blade, a reciprocating electric saw blade, or a pair of electric shearing blades (electric scissors) that perform a shearing action. The specific configuration, arrangement, quantity, materials, and measurement procedures of each component and part may be modified as appropriate without departing from the spirit and scope of the present invention. Furthermore, not all of the components shown in the above embodiments are necessarily required and may be selected as appropriate.

[0091] 1: Bridge 2: Bridge girder 12: Measuring device 16: Surveying equipment 18: Mobile unit 19: Measuring unit 21: Laser unit 26: Base 27: Wheel 28: Wheel drive mechanism 30: Permanent magnet 32: Magnet drive mechanism 41: 360° prism (measuring device, reflective material) 42: Support unit 61: Measuring device 62: Second camera (camera) 81: Measuring device 82: Measuring unit 86: Support unit 87: 3D scanner (measuring device) 88: Weight 89: Telescopic body

Claims

1. A measuring device for measuring a bridge, comprising: a mobile unit that is attached to the bridge girder of the bridge by magnetic force and can move along the bridge girder in the bridge axis direction; and a measuring unit that is attached to the mobile unit and measures the bridge.

2. The measuring device according to claim 1, wherein the moving unit comprises a magnet that generates the magnetic force and a magnet driving mechanism that can change the direction of the magnet.

3. The measurement device according to claim 1, wherein the moving unit comprises a base on which the measurement unit is mounted, a plurality of wheels mounted on the base, and a wheel drive mechanism for driving the wheels, and the wheels are supported on the base without the intervention of elastic elements.

4. The measuring device according to claim 1, wherein the measuring unit comprises a measuring instrument and a support unit attached to the moving unit and supporting the measuring instrument, the support unit being configured to be extendable and retractable in the vertical direction.

5. The measuring device according to claim 1, wherein the measuring unit comprises: a measuring instrument; and a support unit attached to the moving unit and supporting the measuring instrument, the support unit being configured to be extendable and retractable in the horizontal direction.

6. A measuring device as described in claim 5, wherein the support unit has a pair of telescopic bodies that extend and retract on both sides in the horizontal direction, the measuring device being mounted on one of the telescopic bodies, and a weight being mounted on the other of the telescopic bodies.

7. A measuring device according to any one of claims 4 to 6, wherein the measuring instrument is a reflective material for reflecting light emitted from a surveying instrument.

8. A measuring device according to any one of claims 4 to 6, wherein the measuring instrument is a 3D scanner that acquires three-dimensional point cloud data of the bridge.

9. The measuring device according to claim 7, further comprising a laser unit provided on the mobile unit for irradiating a laser beam toward the bridge girder.

10. The measuring device according to claim 9, wherein the laser unit is provided at a position aligned with the reflector in the bridge axis direction.

11. The measuring device according to claim 10, further comprising a camera provided on the mobile unit for photographing a portion of the bridge girder that is hit by the laser light emitted by the laser unit.

12. A method for measuring a bridge, comprising the steps of: preparing a measuring device having a mobile unit that is attached to the bridge girder of the bridge by magnetic force and a measuring unit that is attached to the mobile unit and that measures the bridge; an arrangement step of attaching the measuring device to the bridge girder of the bridge to be measured and moving the mobile unit along the bridge girder in the bridge axis direction to place the measuring unit at a predetermined measurement position; and a measurement step of measuring the bridge using the measuring unit at the measurement position.

Images