Vibration detection device and measurement system

Abstract

This reduces the cost of installing vibration detection devices on roads or bridges, and other traffic routes. [Solution] The vibration detection device (10) comprises a vibration power generation unit (11) that generates a voltage based on vibrations that occur in a passage when an object passes over the passage, a power storage unit (14) that stores power based on that voltage, and a transmitting unit (15) that receives power from the power storage unit (14) and wirelessly transmits a predetermined signal when the stored voltage of the power storage unit (14) exceeds a predetermined voltage.

Description

Technical Field

[0001] The present invention relates to a vibration detection device and a measurement system.

Background Art

[0002] A method for estimating the weight of a vehicle in motion by measuring the strain and deformation of a bridge, Bridge Weigh-in-Motion (BWIM), has been proposed. As BWIM, methods such as using axle detection sensors at two locations on the road surface for detection and attaching strain gauges to bridge members and obtaining the axle passing time and speed from the output waveforms have been proposed.

[0003] In Non-Patent Document 1, a method using a strain gauge, the reaction force method, has been proposed as a BWIM technique. This is a method that utilizes the fact that the reaction force reaches its maximum value when a load is placed directly above the support of the main girder and becomes zero at the moment when the load exits. It measures the fluctuation of the reaction force, detects the passage of the axle weight from the rapidly changing portion, and obtains the axle weight value from the amount of rapid change in strain.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the method using a strain gauge has problems such as high power consumption, the need to secure power for permanent installation, and high installation costs. One aspect of the present invention aims to reduce the installation cost of a vibration detection device on a passageway including a road or a bridge.

Means for Solving the Problems

[0006] To solve the above problems, a vibration detection device according to one aspect of the present invention is installed in a passageway and comprises a vibration power generation unit that generates a voltage based on vibrations that occur in the passageway when a vehicle passes over the passageway, a power storage unit that stores power based on the voltage generated by the vibration power generation unit, and a transmitting unit that receives power from the power storage unit and wirelessly transmits a predetermined signal when the stored voltage of the power storage unit exceeds a predetermined voltage. [Effects of the Invention]

[0007] According to one aspect of the present invention, the cost of introducing vibration detection devices to roads or bridges can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example configuration of a measurement system according to Embodiment 1 of the present invention. [Figure 2] This is a longitudinal cross-sectional view showing one example of the configuration of a vibration power generation unit. [Figure 3] This is a schematic diagram showing an example of a bridge equipped with a vibration power generation unit. [Figure 4] This figure shows an example of the time-dependent changes in the output voltage of the vibration generator, the magnetic flux density inside the magnetostrictive material, and the displacement of the bridge girder when a passenger car passes over the superstructure of a bridge. [Figure 5] This figure shows the results of measuring the output voltage of the vibration power generation unit when a self-contained vibration detection device is installed on a bridge. [Figure 6] This figure shows the time change of the stored voltage of the energy storage capacitor during the measurement period shown in Figure 5. [Figure 7] This is a flowchart showing the control flow of the energy storage capacitor in the measurement system according to Embodiment 1. [Figure 8] This is a flowchart showing the control flow of the energy storage capacitor in the measurement system according to Embodiment 2. [Modes for carrying out the invention]

[0009] [Embodiment 1] Figure 1 is a diagram showing an example configuration of a measurement system according to Embodiment 1 of the present invention. The measurement system 1 shown in Figure 1 is a system that measures the weight of objects traveling on a passageway and monitors the remaining lifespan of the passageway. A passageway includes, for example, roads or bridges. Roads include, for example, roads as defined by the Road Traffic Act. Bridges include, for example, road bridges, pedestrian bridges, and railway bridges. Objects traveling on a passageway include, for example, vehicles, railway vehicles, and pedestrians. When objects travel on a passageway, vibrations are generated in the passageway, and if the passageway is damaged by these vibrations, the remaining lifespan of the passageway is shortened.

[0010] The measurement system 1 comprises a vibration detection device 10 and a receiving device 20. The vibration detection device 10 includes a vibration power generation unit 11, a rectifier circuit 12, a power management circuit 13, a power storage capacitor 14, and a transmitting unit 15.

[0011] The vibration power generation unit 11 is a vibration power generation device installed in a passageway that generates an alternating current voltage corresponding to the vibrations generated in the passageway when a vehicle passes over it. Hereinafter, the alternating current voltage generated in the vibration power generation unit 11 will be referred to as the output voltage. The vibration power generation unit 11 has internal resistance, and an alternating current corresponding to the output voltage flows through the rectifier circuit 12.

[0012] The rectifier circuit 12 rectifies the alternating current corresponding to the output voltage of the vibration power generation unit 11. The rectifier circuit 12 is composed of, for example, a bridge circuit with multiple diodes. The rectifier circuit 12 outputs the rectified direct current (pulsating current) to the power management circuit 13.

[0013] The power management circuit 13 is a circuit that controls the energy storage capacitor 14. The power management circuit 13 is composed of a combination of multiple electrical circuits, such as a comparator. The energy storage capacitor 14 is an energy storage unit that stores power based on the output voltage generated by the vibration power generation unit 11. The power management circuit 13 causes the energy storage capacitor 14 to store power based on the DC current output by the rectifier circuit 12. When the storage voltage of the energy storage capacitor 14 exceeds a predetermined voltage, the power management circuit 13 supplies the power stored in the energy storage capacitor 14 to the transmission unit 15. Here, the predetermined voltage is, for example, 2.5V.

[0014] The transmitting unit 15 is a communication device that wirelessly transmits a predetermined signal to the receiving device 20. The transmitting unit 15 communicates wirelessly with the receiving device 20 via a wireless communication network such as Sigfox®. The rated voltage of the transmitting unit 15 is less than or equal to the storage voltage (predetermined voltage) of the energy storage capacitor 14 at which power supply from the energy storage capacitor 14 begins, for example, 2.5V.

[0015] When the storage voltage of the energy storage capacitor 14 exceeds a predetermined voltage, the transmitting unit 15 receives power from the energy storage capacitor 14 and wirelessly transmits a predetermined signal to the receiving device 20. In Embodiment 1, the predetermined signal transmitted by the transmitting unit 15 indicates that the cumulative weight of multiple objects that have passed over the passageway on which the vibration detection device 10 is installed has exceeded a predetermined value. This predetermined signal includes information for identifying the passageway on which the cumulative weight has exceeded the predetermined value. The information for identifying the passageway includes, for example, the serial number of the vibration detection device 10, identification information indicating the passageway, and the installation location of the vibration power generation unit 11.

[0016] The receiving device 20 is, for example, a server used for the maintenance and management of a traffic path. The receiving device 20 includes, for example, a control unit 21, a storage unit 22, and a receiving unit 23. The control unit 21 controls all parts of the receiving device 20. The storage unit 22 is a storage device that stores various data used by the receiving device 20. The receiving unit 23 receives a predetermined signal transmitted by the transmitting unit 15 of the vibration detection device 10.

[0017] The control unit 21 of the receiving device 20 may function as an estimation unit 210 by executing the program stored in the storage unit 22. The estimation unit 210 according to Embodiment 1 estimates an integrated value of the weights of a plurality of passing objects that have passed through the passage based on, for example, the number of times the receiving unit 23 has received a predetermined signal. The estimation unit 210 of the receiving device 20 according to Embodiment 1 may estimate the traffic load applied to the passage where the vibration detection device 10 is installed, the degree of damage to the passage, or the remaining life of the passage based on the estimation result of the integrated value of the weights of a plurality of passing objects that have passed through the passage.

[0018] FIG. 2 is a longitudinal sectional view showing a configuration example of the vibration power generation unit 11. The vibration power generation unit 11 shown in FIG. 2 includes a magnetic coil 30, a magnetostrictive rod 31, a permanent magnet 32, an input unit 33, a yoke 34, and a base 35. The vibration power generation unit 11 is a power generation unit that generates an alternating voltage corresponding to the vibration input from the vibration source, and is also a vibration sensor that detects the vibration input from the vibration source. The base 35 is used to fix the vibration power generation unit 11. The magnetic coil 30, the magnetostrictive rod 31, the permanent magnet 32, the input unit 33, and the yoke 34 are placed on the base 35.

[0019] The magnetostrictive rod 31 is a magnetostrictive member made of a magnetostrictive material and is the core of the magnetic coil 30. As the magnetostrictive material, for example, Galfenol (Fe (iron)-Ga (gallium) alloy), Terfenol-D (Tb-Dy-Fe-based alloy), etc. can be used.

[0020] The permanent magnet 32 is configured in an annular shape and magnetized in the axial direction. The input unit 33 and the yoke 34 are made of a magnetic material. As the magnetic material, for example, ferromagnetic stainless steel, martensitic stainless steel, carbon steel, silicon steel, etc. having magnetism can be used. The permanent magnet 32, the input unit 33, and the yoke 34 constitute a magnetic circuit that applies a bias magnetic field to the magnetic coil 30 and the magnetostrictive rod 31.

[0021] The input unit 33 receives vibration input from a passageway or the like. When vibration is input to the input unit 33 from a passageway or the like, compressive stress is applied to the magnetostrictive rod 31 from the input unit 33. At this time, the magnetic flux density inside the magnetostrictive rod 31 changes due to the compressive stress from the input unit 33, which induces an electromotive force in the magnetic coil 30. The output voltage of the vibration power generation unit 11 changes in accordance with the induced electromotive force generated in the magnetic coil 30.

[0022] The magnetostrictive rod 31 is designed with an axial length and axial stiffness such that it is effectively compressed by the compressive stress applied from the input section 33 when, for example, a medium-sized vehicle such as a passenger car passes through a road. The axial stiffness of the magnetostrictive rod 31 is lower than the axial stiffness of the base 35.

[0023] The bias magnetic field applied to the magnetic coil 30 and magnetostrictive rod 31 is designed such that, for example, when a medium-sized vehicle such as a passenger car passes through a road, the compressive stress applied to the magnetostrictive rod 31 from the input unit 33 causes the output voltage of the vibration power generation unit 11 to reach a predetermined value. The axial length and axial stiffness of the magnetostrictive rod 31, as well as the bias magnetic field applied to the magnetic coil 30 and magnetostrictive rod 31, are determined so that the vibration power generation unit 11 can obtain an output voltage tens to hundreds of times higher than that of a typical acceleration sensor that utilizes inertial force.

[0024] Figure 3 is a schematic diagram showing an example of a bridge on which a vibration power generation unit 11 is installed. The bridge 50 shown in Figure 3 has a superstructure 51 including bridge girders, a substructure 52 including abutments and piers, and bearings 53 provided between the superstructure 51 and the substructure 52. In Figure 3, a passenger car 60, an example of a vehicle, is driving on the superstructure 51.

[0025] The vibration power generation unit 11 of the vibration detection device 10 is installed between the superstructure 51 and the substructure 52 of the bridge 50. The vibration power generation unit 11 has its base 35 fixed to the substructure 52 of the bridge 50, and its input unit 33 is in contact with the superstructure 51 of the bridge 50. Of the parts of the vibration detection device 10 other than the vibration power generation unit 11 do not need to be installed between the superstructure 51 and the substructure 52 and are not in contact with the superstructure 51 of the bridge 50. The circuit elements constituting the power management circuit 13 have a positive power supply terminal (V CC , V DD If there are other components (such as) that require power supply to the power management circuit 13 from an external power source, it is preferable to place the external power source in a location that is easy to maintain, inspect, and replace.

[0026] When a passenger car 60 is positioned on the superstructure 51 of the bridge 50, the weight of the passenger car 60 causes the superstructure 51 of the bridge 50 to descend. Therefore, when a passenger car 60 passes over the superstructure 51 of the bridge 50, vibrations occur in the superstructure 51 of the bridge 50. When these vibrations are input to the input section 33, which is in contact with the superstructure 51, an output voltage is generated in the vibration power generation section 11.

[0027] Figure 4 shows an example of the time changes of the output voltage of the vibration power generation unit 11, the magnetic flux density of the magnetostrictive rod 31, and the displacement of the bridge girder when a passenger car 60 passes over the superstructure 51 of the bridge 50. In the upper part of Figure 4, the horizontal axis represents time, and the vertical axis shows the time change of the output voltage of the vibration power generation unit 11. As shown in the upper part of Figure 4, the vibration power generation unit 11 detects vibration caused by the passage of the front wheels of the passenger car at time t1, and detects vibration caused by the passage of the rear wheels of the passenger car at time t2, which is later than time t1.

[0028] The middle section of Figure 4 shows the time variation of the magnetic flux density of the magnetostrictive rod 31 on the vertical axis, with the horizontal axis representing time. The magnetic flux density of the magnetostrictive rod 31 shown in the middle section of Figure 4 is obtained by integrating the output voltage of the vibration power generation unit 11 shown in the upper section of Figure 4. The lower section of Figure 4 shows the time variation of the bridge girder displacement on the vertical axis, with the horizontal axis representing time. The bridge girder displacement shown in the lower section of Figure 4 is a value measured with a laser displacement meter. As shown in the lower section of Figure 4, the bridge girder of bridge 50 descends by approximately 0.1 mm at time t1 and by a further approximately 0.4 mm at time t2. As shown in the middle section of Figure 4, the magnetic flux density of the magnetostrictive rod 31 decreases at time t1, and further decreases at time t2. From Figure 4, it can be seen that the time variation of the magnetic flux density of the magnetostrictive rod 31 is highly correlated with the time variation of the bridge girder displacement of bridge 50.

[0029] Figure 5 shows the results of measuring the output voltage of the vibration power generation unit 11 when the vibration detection device 10 is installed on a bridge. The measurement period shown in Figure 5 is longer than that of the graph shown in the upper part of Figure 4. Figure 6 shows the time change of the stored voltage of the energy storage capacitor 14 during the measurement period shown in Figure 5. The stored voltage of the energy storage capacitor 14 is accumulated each time the output voltage of the vibration power generation unit 11 increases due to vehicles such as passenger cars passing over the bridge. From the relationship shown in Figures 5 and 6, it can be seen that the cumulative weight of multiple vehicles that have passed over the bridge can be estimated based on the stored voltage of the energy storage capacitor 14.

[0030] Furthermore, in Figure 6, the stored voltage of the energy storage capacitor 14 exceeds a predetermined voltage (2.5V) within a period of 2500 to 3000 seconds from the start of measurement. Therefore, the vibration detection device 10 installed on the bridge can supply power from the energy storage capacitor 14 to the transmitting unit 15.

[0031] Figure 7 is a flowchart showing the control flow of the energy storage capacitor 14 in the measurement system 1 according to Embodiment 1. The control shown in Figure 7 is performed by the power management circuit 13.

[0032] In S100, the power management circuit 13 stores power in the energy storage capacitor 14. When a vehicle passes over the passageway on which the vibration power generation unit 11 is installed, the vibration power generation unit 11 generates an output voltage corresponding to the vibrations generated in the passageway. The alternating current corresponding to the output voltage of the vibration power generation unit 11 is rectified by the rectifier circuit 12, and a direct current (pulsating current) corresponding to the output voltage of the vibration power generation unit 11 is output from the rectifier circuit 12 to the power management circuit 13. Based on the current from the rectifier circuit 12, the power management circuit 13 charges the energy storage capacitor 14. The power management circuit 13 continues charging the energy storage capacitor 14 and proceeds to control in S110.

[0033] In S110, the power management circuit 13 determines whether the storage voltage of the energy storage capacitor 14 has exceeded a predetermined voltage. The power management circuit 13 may, for example, use a comparator to determine whether the storage voltage of the energy storage capacitor 14 has exceeded a predetermined voltage. Until the storage voltage of the energy storage capacitor 14 exceeds the predetermined voltage (S110: NO), the power management circuit 13 proceeds to control S100 and continues to store energy in the energy storage capacitor 14. If the storage voltage of the energy storage capacitor 14 exceeds the predetermined voltage (S110: YES), the power management circuit 13 proceeds to control S120.

[0034] In S120, the power management circuit 13 starts supplying power from the energy storage capacitor 14 to the transmitter 15. The transmitter 15 is activated by the power supplied from the energy storage capacitor 14 and wirelessly transmits a predetermined signal to the receiving device 20.

[0035] In S130, the power management circuit 13 terminates the power supply from the energy storage capacitor 14 to the transmitter 15. The power management circuit 13 may terminate the power supply when it receives a signal from the transmitter 15 indicating the completion of transmission of a predetermined signal, or it may terminate the power supply after a predetermined time has elapsed since the start of power supply to the transmitter 15. The predetermined time is longer than the time required from the start of operation of the transmitter 15 until the completion of transmission of the predetermined signal. After the power management circuit 13 terminates the power supply from the energy storage capacitor 14 to the transmitter 15, it proceeds to control S140. In S140, the power management circuit 13 discharges the remaining power in the energy storage capacitor 14. After that, the power management circuit 13 proceeds to control S100. The power management circuit 13 starts storing energy in the energy storage capacitor 14 again.

[0036] The power management circuit 13 may disconnect the electrical connection between the rectifier circuit 12 and the energy storage capacitor 14 between the control of S120 and the control of S140. If the electrical connection between the rectifier circuit 12 and the energy storage capacitor 14 is disconnected between the control of S120 and the control of S140, the electrical connection is restored before proceeding to the control of S100, enabling the storage of energy in the energy storage capacitor 14.

[0037] As described above, the transmitting unit 15 transmits a predetermined signal to the receiving unit 23 of the receiving device 20 when the voltage exceeds a predetermined value. The estimation unit 210 then estimates the cumulative weight of multiple objects that have passed through the passageway based on the predetermined voltage and the number of times the receiving unit 23 has received the predetermined signal. According to this embodiment, the cumulative weight of objects passing through the passageway can be estimated with a small output voltage.

[0038] [Embodiment 2] Other embodiments of the present invention are described below. For the sake of clarity, components having the same function as those described in the above embodiments will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0039] The measurement system 1 according to Embodiment 2 differs from that of Embodiment 1 in that the timing at which the transmitting unit 15 transmits a predetermined signal is different. In the measurement system 1 according to Embodiment 2, the transmitting unit 15 transmits a predetermined signal to the receiving device 20 when the weight of an object that has traveled along the passage exceeds a predetermined threshold. In other words, in the measurement system 1 according to Embodiment 2, the predetermined signal transmitted by the transmitting unit 15 to the receiving device 20 indicates that the weight of an object that has traveled along the passage has exceeded a predetermined threshold.

[0040] The weight of vehicles permitted to travel on public roads is limited to a total weight of 20 tons or less and an axle weight of 10 tons or less, according to Article 47 of the Road Act and Article 3 of the Vehicle Restriction Ordinance. Vehicles exceeding the permissible weight due to overloading or other reasons can cause wear and cracking of the road surface and damage to bridge structures. Therefore, in the measurement system 1 according to Embodiment 2, for example, when the total weight of a vehicle traveling on a road on which the vibration power generation unit 11 is installed exceeds 20 tons, the transmitting unit 15 transmits a predetermined signal to the receiving device 20. This predetermined signal indicates that a vehicle exceeding the permissible weight has traveled on a road on which the vibration power generation unit 11 is installed.

[0041] In the measurement system 1 according to Embodiment 2, when the weight of an object passing through a passage exceeds a predetermined threshold, the vibration power generation unit 11 supplies power to the energy storage capacitor 14 such that the stored voltage of the energy storage capacitor 14 exceeds a predetermined voltage. The power supplied by the vibration power generation unit 11 to the energy storage capacitor 14 can be adjusted by the bias magnetic field applied to the magnetic coil 30 and the magnetostrictive rod 31, the axial length of the magnetostrictive rod 31, and the axial rigidity.

[0042] In the measurement system 1 according to Embodiment 2, the number of times the receiving unit 23 receives a predetermined signal indicates the number of times a vehicle weighing more than or equal to a predetermined threshold has passed over the passageway. Based on the number of times the receiving unit 23 has received a predetermined signal, the estimation unit 210 estimates the degree of damage to the passageway or the remaining lifespan of the passageway when a vehicle weighing more than a predetermined threshold has passed over it.

[0043] Figure 8 is a flowchart showing the control flow of the energy storage capacitor 14 in the measurement system 1 according to Embodiment 2. The control shown in Figure 8 is performed by the power management circuit 13.

[0044] In S200, the power management circuit 13 switches the circuits included in the power management circuit 13 so that current from the rectifier circuit 12 flows to the energy storage capacitor 14. After that, the power management circuit 13 waits until the stored voltage of the energy storage capacitor 14 increases (S210:NO).

[0045] When a vehicle passes over a passageway on which the vibration power generation unit 11 is installed, the vibration power generation unit 11 generates an output voltage corresponding to the vibrations generated in the passageway. The alternating current corresponding to the output voltage of the vibration power generation unit 11 is rectified by the rectifier circuit 12, and a direct current (pulsating current) corresponding to the output voltage of the vibration power generation unit 11 is output from the rectifier circuit 12 to the power management circuit 13. The power management circuit 13 charges the energy storage capacitor 14 based on the current from the rectifier circuit 12. If the stored voltage of the energy storage capacitor 14 increases (S210:YES) and the stored voltage of the energy storage capacitor 14 exceeds a predetermined voltage (S220:YES), the power management circuit 13 proceeds to control S230. If the stored voltage of the energy storage capacitor 14 increases (S210:YES) and the stored voltage of the energy storage capacitor 14 is below a predetermined voltage (S220:NO), the power management circuit 13 proceeds to control S250.

[0046] In S230, the power management circuit 13 starts supplying power from the energy storage capacitor 14 to the transmitter 15. The transmitter 15 is started by the power supplied from the energy storage capacitor 14 and wirelessly transmits a predetermined signal to the receiving device 20. In the following S240, the power management circuit 13 stops supplying power from the energy storage capacitor 14 to the transmitter 15. The power management circuit 13 may stop supplying power when it receives a signal from the transmitter 15 indicating the completion of transmission of the predetermined signal, or it may stop supplying power after a predetermined time has elapsed since the start of power supply to the transmitter 15, or it may stop supplying power after a predetermined time has elapsed since the vibration power generation unit 11 has generated an output voltage. The predetermined time is longer than the time required from the start of power supply to the transmitter 15 until the completion of transmission of the predetermined signal. After stopping the supply of power from the energy storage capacitor 14 to the transmitter 15, the power management circuit 13 proceeds to control S250. In S250, the power management circuit 13 discharges the remaining power in the energy storage capacitor 14. Subsequently, the power management circuit 13 proceeds to control S210. The power management circuit 13 may also disconnect the electrical connection between the rectifier circuit 12 and the energy storage capacitor 14 between control S220 and control S250. If the electrical connection between the rectifier circuit 12 and the energy storage capacitor 14 is disconnected between control S220 and control S250, the electrical connection is restored before proceeding to control S210, enabling energy storage in the energy storage capacitor 14.

[0047] [Variation] The vibration power generation unit 11 is not limited to the one shown in Figure 2. For example, a permanent magnet 32 ​​and a yoke 34 may be placed in the center, and magnetostrictive members may be arranged concentrically around the magnetic coil 30. Alternatively, a weight may be provided on the base 35, and an elastic member such as a spring may be provided below the weight. With such a configuration, continuous vibration can be generated by the action of the weight and the elastic member, thereby increasing the amount of power generated. Furthermore, for example, the vibration power generation unit 11 may be other sensors such as piezoelectric sensors, as long as they generate a voltage in response to the vibration of the vibration source. Also, in the vibration power generation unit 11, the magnetic circuit that applies a bias magnetic field to the magnetic coil 30 and the magnetostrictive rod 31 only needs to be composed of at least a permanent magnet 32.

[0048] In Figure 3, the vibration power generation unit 11 is installed between the superstructure 51 and the substructure 52 of the bridge 50. However, the traffic routes on which the vibration power generation unit 11 is installed are not limited to bridges used by passenger cars 60. For example, it could be installed between the superstructure and substructure of a pedestrian bridge used by pedestrians, or inside a manhole in the road.

[0049] The power management circuit 13 may be configured separately from the vibration detection device 10. For example, the power management circuit 13 may be configured to control the energy storage capacitors 14 of multiple vibration detection devices 10. The power management circuit 13 may be distributed and located at locations physically separated from the vibration detection device 10. For example, the power management circuit 13 may be located near an external power supply that provides power to the power management circuit 13. If the power management circuit 13 is distributed and located separately from the vibration detection device 10, the power management circuit 13 may be electrically connected to the parts of the vibration detection device 10 other than the power management circuit 13 by electrical wiring or the like. The power management circuit 13 may be provided to communicate with the receiving device 20, and may be controlled by the control unit 21 of the receiving device 20.

[0050] The vibration detection device 10 may include multiple units of each component. The vibration power generation unit 11 may be placed, for example, one at each position corresponding to the left wheel and the right wheel of the passenger car 60. If the vibration detection device 10 includes multiple vibration power generation units 11, a rectifier circuit 12 and an energy storage capacitor 14 may be provided for each vibration power generation unit 11.

[0051] In the above embodiment, power based on the output voltage of the vibration power generation unit 11 is stored in the energy storage capacitor 14. However, the energy storage unit that stores power based on the output voltage of the vibration power generation unit 11 is not limited to the energy storage capacitor 14. For example, power based on the output voltage of the vibration power generation unit 11 may be stored in a battery or the like.

[0052] 〔summary〕 A vibration detection device according to embodiment 1 of the present invention is installed in a passageway and comprises a vibration power generation unit that generates a voltage based on vibrations generated in the passageway when a vehicle passes over the passageway, a power storage unit that stores power based on the voltage generated by the vibration power generation unit, and a transmission unit that receives power from the power storage unit and wirelessly transmits a predetermined signal when the stored voltage of the power storage unit exceeds a predetermined voltage.

[0053] Since the transmission unit receives power from the energy storage unit and transmits a predetermined signal, the vibration detection device does not require an external power source. Therefore, the vibration detection device according to one aspect of the present invention can reduce the cost of introducing it into traffic routes. Such effects contribute, for example, to achieving United Nations Sustainable Development Goals (SDGs) Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," and Goal 11, "Make cities and human settlements inclusive, safe, resilient and sustainable."

[0054] In the vibration detection device according to embodiment 2 of the present invention, in embodiment 1, the device may be configured such that the power remaining in the power storage unit is discharged after the transmitting unit has wirelessly transmitted the predetermined signal.

[0055] With the above configuration, the vibration detection device can repeatedly detect when an object passes through the passageway.

[0056] In the vibration detection device according to embodiment 3 of the present invention, in embodiment 1 or 2 above, the predetermined signal transmitted wirelessly by the transmitting unit may be configured to indicate that the cumulative weight of a plurality of objects that have passed over the passageway exceeds a predetermined value.

[0057] According to the above configuration, the transmitting unit wirelessly transmits a predetermined signal indicating that the cumulative weight of multiple objects that have traveled on the passageway exceeds a predetermined value, thereby providing the receiving device and the like with information that can be used to estimate the remaining lifespan of the passageway.

[0058] In the vibration detection device according to embodiment 4 of the present invention, in embodiment 1, the vibration power generation unit may supply power to the power storage unit such that the stored voltage exceeds the predetermined voltage when the passing object, whose weight exceeds a predetermined threshold, passes over the passageway.

[0059] According to the above configuration, it is possible to determine whether an object that has passed through the passage has a weight exceeding a predetermined threshold based on the stored voltage accumulated in the energy storage unit.

[0060] In the vibration detection device according to aspect 5 of the present invention, in aspect 4 above, the device may be configured such that the power remaining in the energy storage unit is discharged after a predetermined time has elapsed since the vibration power generation unit generated a voltage.

[0061] According to the above configuration, the vibration detection device can repeatedly detect when a vehicle with a weight exceeding a predetermined threshold passes through a passageway.

[0062] In the vibration detection device according to embodiment 6 of the present invention, in embodiment 4 or 5 above, the predetermined signal transmitted wirelessly by the transmitting unit may be configured to indicate that the weight of the object passing over the passage exceeds the predetermined threshold.

[0063] According to the above configuration, the transmitting unit wirelessly transmits a predetermined signal indicating that the weight of an object that has traveled on the passageway exceeds a predetermined threshold, thereby providing the receiving device with information that can be used to estimate the remaining lifespan of the passageway.

[0064] In the vibration detection device according to embodiment 7 of the present invention, in any of embodiments 1 to 6 above, the vibration power generation unit is composed of a magnetic coil, a magnetostrictive member made of a magnetostrictive material, and a magnetic material, and when vibration from the passageway is input, it has an input unit that applies compressive stress to the magnetostrictive member, and a magnetic circuit that applies a magnetic field to the magnetic coil and the magnetostrictive member, and the device is configured such that an induced electromotive force is generated in the magnetic coil as the magnetic flux density of the magnetostrictive member changes in response to the compressive stress input from the input unit.

[0065] With the above configuration, the power required for the transmitting unit to transmit a predetermined signal can be efficiently stored in the energy storage unit.

[0066] In the vibration detection device according to embodiment 8 of the present invention, in embodiment 7 above, the passageway is a bridge, the vibration power generation unit is installed between the superstructure and the substructure of the bridge, and the input unit may be in contact with the superstructure of the bridge.

[0067] According to the above configuration, the vibration generator is installed between the superstructure and substructure of the bridge, so the wheel load is not directly applied to the input of the vibration generator. Therefore, the vibration generator is less susceptible to damage due to load, reducing the frequency of parts replacement and lowering the cost of introducing vibration detection devices to roads or bridges. Such effects contribute to achieving, for example, United Nations Sustainable Development Goals (SDGs) Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," and Goal 11, "Make cities and human settlements inclusive, safe, resilient and sustainable."

[0068] Conventional strain gauges are often attached to the object being measured with adhesive. Bridges can be subjected to environments that degrade adhesives, such as high temperatures, low temperatures, and high humidity. If strain gauges are attached to the bridge's superstructure with adhesive, the adhesive may deteriorate, causing the strain gauges to detach from the object being measured and making measurement impossible. With the above configuration, the vibration power generation unit only needs to be positioned so that its input part is in contact with the bridge's superstructure, and it is not necessary to attach the input part to the bridge's superstructure with adhesive. Therefore, the vibration detection device is more durable than those that use conventional strain gauges.

[0069] A measurement system according to aspect 9 of the present invention is a measurement system comprising a vibration detection device according to any of aspects 1 to 3, aspects 7 and 8, and a receiving device, wherein the receiving device comprises a receiving unit that receives the predetermined signal wirelessly transmitted by the transmitting unit, and an estimation unit that estimates the cumulative weight of a plurality of objects that have traveled along the passage based on the number of times the receiving unit has received the predetermined signal.

[0070] A measurement system according to aspect 9 of the present invention is a measurement system comprising a vibration detection device according to any of aspects 1 to 8 above and a receiving device, wherein the receiving device comprises a receiving unit that receives the predetermined signal wirelessly transmitted by the transmitting unit and an estimation unit that estimates the remaining lifespan of the passageway based on the number of times the receiving unit has received the predetermined signal.

[0071] With the above configuration, the measurement system can estimate the remaining lifespan of the road based on the results estimated by the estimation unit.

[0072] [Additional notes] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0073] 1. Measurement System 10. Vibration detection device 11. Vibration power generation section 14. Capacitor for energy storage (energy storage section) 15 Transmitter 20 Receiving device 30 Magnetic coils 31 Magnetostrictive rod (magnetostrictive member) 32 Permanent Magnets 33 Input section 34 York 50 Bridges 51 Superstructure 52 Substructure 53 Bearing 60 Passenger Cars 210 Estimation Department

Claims

1. A vibration power generation unit installed in a passageway generates a voltage based on vibrations that occur in the passageway when a vehicle passes over it, A power storage unit that stores power based on the voltage generated by the vibration power generation unit, A vibration detection device comprising a transmitting unit that receives power from the energy storage unit and wirelessly transmits a predetermined signal when the stored voltage of the energy storage unit exceeds a predetermined voltage.

2. The vibration detection device according to claim 1, wherein the power remaining in the power storage unit is discharged after the transmitting unit has wirelessly transmitted the predetermined signal.

3. The vibration detection device according to claim 2, wherein the predetermined signal transmitted wirelessly by the transmitting unit indicates that the cumulative weight of a plurality of objects that have traveled over the passageway exceeds a predetermined value.

4. The vibration detection device according to claim 1, wherein when a passing object with a weight exceeding a predetermined threshold passes over the passageway, the vibration power generation unit supplies power to the power storage unit such that the stored voltage exceeds the predetermined voltage.

5. The vibration detection device according to claim 4, wherein the power remaining in the energy storage unit is discharged after a predetermined time has elapsed since the vibration power generation unit generated a voltage.

6. The vibration detection device according to claim 4, wherein the predetermined signal transmitted wirelessly by the transmitting unit indicates that the weight of the object passing over the passage exceeds the predetermined threshold.

7. The vibration power generation unit is A magnetic coil and A magnetostrictive member made of a magnetostrictive material, It is made of a magnetic material, and when vibrations from the passage are input, it applies compressive stress to the magnetostrictive member, The magnetic circuit comprises the magnetic coil and the magnetostrictive member, The vibration detection device according to claim 1, wherein the magnetic flux density of the magnetostrictive member changes in response to the compressive stress input from the input unit, thereby generating an induced electromotive force in the magnetic coil.

8. The aforementioned passageway is a bridge, The vibration power generation unit is installed between the superstructure and the substructure of the bridge. The vibration detection device according to claim 7, wherein the input unit is in contact with the superstructure of the bridge.

9. The vibration detection device according to claim 2, A measurement system comprising a receiving device, The receiving device includes a receiving unit that receives the predetermined signal wirelessly transmitted by the transmitting unit, A measurement system comprising: an estimation unit that estimates the cumulative weight of a plurality of objects that have traveled along the passage path based on the number of times the receiving unit has received the predetermined signal.

10. A vibration detection device according to claim 2 or 4, A measurement system comprising a receiving device, The receiving device includes a receiving unit that receives the predetermined signal wirelessly transmitted by the transmitting unit, A measurement system comprising: an estimation unit that estimates the remaining lifespan of the passageway based on the number of times the receiving unit has received the predetermined signal.

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