Sensor unit, sensor system, and sensing method

Abstract

This sensor unit is fixed to a movement path along which a moving body moves, and includes: an environmental power generation device that generates power using electromagnetic energy emitted into the surrounding environment when the moving body passes through the movement path; and a sensor that receives the power generated by the environmental power generation device and performs sensing. This sensing method for performing sensing with a sensor unit fixed to a movement path along which a moving body moves includes: an environmental power generation step for generating power using electromagnetic energy emitted into the surrounding environment when the moving body passes through the movement path; and a step for receiving the power generated in the environmental power generation step and performing sensing.

Description

Sensor unit, sensor system, and sensing method

[0001] The present invention relates to a sensor unit, a sensor system, and a sensing method.

[0002] Patent Document 1 describes a "rail tread measuring device that provides digital data that quantifies the position and shape of rail irregularities." Patent Document 2 describes an "uneven wear amount estimation system that, when a vibration sensor is installed on the rail, reduces the impact of vibration damping in the rail on uneven wear amount estimation." Patent Document 3 describes a "method and system for changing operation restriction reference values ​​for rail temperatures during and after earthquakes at high temperatures." Patent Document 4 describes an "antenna device, rectifier circuit, and electronic device with energy harvesting function." [Prior art documents] [Patent documents] [Patent document 1] JP 2023-173859 A [Patent document 2] JP 2021-124294 A [Patent document 3] JP 2017-003407 A [Patent document 4] WO 2021 / 261076 A General disclosure

[0003] A first aspect of the present invention provides a sensor unit that is fixed to a path along which a moving object moves, and includes an energy harvesting device that generates power using electromagnetic energy emitted into the surrounding environment when the moving object passes through the path, and a sensor that receives and senses the power generated by the energy harvesting device.

[0004] The device may further include a sensing board on which the sensor is mounted, and the sensing board may include an arithmetic circuit and a communication device that operate using power generated by the environmental power harvesting device, the arithmetic circuit performing arithmetic processing on the results of the sensing, and the communication device communicating the results of the sensing with an external device.

[0005] The moving body may be a train, and the moving path may be a rail.

[0006] The moving object may be a vehicle, and the travel path may be a road for the vehicle.

[0007] The sensor may include multiple sensing chips, and the multiple sensing chips may communicate with each other by magnetic field coupling or magnetic field resonance.

[0008] The electromagnetic energy may be electromagnetic wave noise or inverter noise.

[0009] The electromagnetic energy may be collected from the path of travel.

[0010] The electromagnetic energy may be collected from space in the environment.

[0011] The sensor may further include a fixing metal plate for fixing the sensor unit to the movement path, and a magnet for fixing the sensor unit to the fixing metal plate.

[0012] The energy harvesting device may further include a storage battery that stores the power generated by the energy harvesting device.

[0013] The sensor may perform sensing of the movement path by detecting at least one of vibrations applied to the sensor unit, pressure changes, and temperature changes around the sensor unit as the moving object passes by.

[0014] In a second aspect of the present invention, there is provided a sensor system comprising the sensor unit described above and a server that receives and analyzes the sensing result from the sensor unit.

[0015] A third aspect of the present invention provides a sensing method for performing sensing using a sensor unit fixed to a path along which a moving object moves, the sensing method including: an energy harvesting step of generating power using electromagnetic energy emitted into the surrounding environment as the moving object passes through the path; and a step of receiving power generated by the energy harvesting step and sensing the state of the path.

[0016] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions.

[0017] 1A and 1B are schematic diagrams illustrating a sensor system 400 according to a first embodiment; a sensor unit 100 according to a first embodiment; a plurality of sensing chips 11, 21, and 31 according to a first embodiment; a sensor unit 100a according to another embodiment; an energy harvesting device 110 according to a first embodiment; an explanatory diagram of electromagnetic energy 501 according to a first embodiment; a first example of a method for fixing a sensor unit 100 according to a first embodiment to a rail 203; a first example of a method for fixing a sensor unit 100 according to a first embodiment to a rail 203; a second example of a method for fixing a sensor unit 100 according to a first embodiment to a rail 203; a second example of a method for fixing a sensor unit 100 according to a first embodiment to a rail 203; a sensor system 401 according to a second embodiment; an example of a method for fixing a sensor unit 100 according to a second embodiment to a sleeper 204; a second example of a method for fixing a sensor unit 100 according to a second embodiment to a sleeper 204; 4 illustrates a sensor system 402 according to a third embodiment.

[0018] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0019] 1 schematically shows a sensor system 400 according to the first embodiment. The sensor system 400 includes a plurality of sensor units 100 fixed to a rail 203, and an information processing unit 300. The information processing unit 300 includes a base station 301, a server 302, and a user interface 303. The server 302 and the sensor units 100 communicate with each other via wireless communication via the base station 301, for example. The user interface 303 displays information calculated by the server 302, etc.

[0020] The sensor system 400 detects the state or a change in state of the object to be measured using the sensor unit 100. Detecting the state or a change in state of the object to be measured means detecting one or more values ​​or amounts of change of the object to be measured, for example, volume, temperature, vibration, pressure, electromagnetic waves, volume, humidity, etc.

[0021] 1 shows an example in which the object to be measured is a rail 203. As shown in Fig. 1, a train 200 receives power from an overhead line 201 via a pantograph 202. The rail 203 is installed on a base of sleepers 204, and two sensor units 100 are installed on the side of the rail 203.

[0022] The server 302 and the user interface 303 may be, for example, an information processing device such as a personal computer.

[0023] FIG. 2 schematically illustrates a sensor unit 100 according to the first embodiment. The sensor unit 100 includes an energy harvesting device 110 that generates power using energy present in the environment in which it is installed, a secondary battery 120, a backup battery 140, and a sensing board 130 on which a sensor is mounted. The sensing board 130 includes multiple sensing chips 11, 21, and 31, a power supply control unit 40, and a communication module 50. The sensing chips 11, 21, and 31, the power supply control unit 40, and the communication module 50 mounted on the sensing board 130 operate on power generated by the energy harvesting device 110. The energy harvesting device 110 is connected to the external environment via a positive connection terminal 101 and a negative connection terminal 102. The power supply control unit 40 is connected to the sensing chips 11, 21, and 31, the secondary battery 120, and the backup battery 140, and controls the power between them. The communication module 50 is a Bluetooth (registered trademark) chip that serves as a communication unit for communicating with the outside world. The communication module 50 may include a chip antenna.

[0024] 3 schematically illustrates the multiple sensing chips 11, 21, and 31 according to the first embodiment. The multiple sensing chips 11, 21, and 31 are examples of sensors mounted on the sensing substrate 130. The multiple sensing chips 11, 21, and 31 receive power generated by the energy harvesting device 110 and perform sensing.

[0025] The sensing chips 11, 21, 31 each include a transmitting coil 12, 22, 32, a receiving coil 13, 23, 33, a transmitting conversion circuit 14, 24, 34 and a receiving conversion circuit 15, 25, 35 that supply signals to the transmitting coils 12, 22, 32 and the receiving coils 13, 23, 33, an arithmetic circuit 16, 26, 36, a memory unit 18, 28, 38 that stores information related to the signals, and a power supply 17, 27, 37 that supplies power to the transmitting conversion circuit 14, 24, 34 and the receiving conversion circuit 15, 25, 35.

[0026] The sensing chips 11, 21, and 31 are configured to be able to communicate with each other through magnetic field coupling or magnetic field resonance. Communication through magnetic field coupling is a transmission method that uses the principle of electromagnetic induction to transmit information. Communication through magnetic field resonance is a transmission method that uses the resonance phenomenon of a coil to transmit information. The resonance phenomenon of a coil refers to the phenomenon in which magnetic field vibrations generated by a current flowing at a certain frequency through one coil are transmitted to another coil at the same frequency.

[0027] The sensing chips 11, 21, and 31 calculate the state of the sensor unit 100 by detecting the state of communication between the sensing chips 11, 21, and 31. The state of the sensor unit 100 may include, for example, at least one of vibration, pressure change, or temperature change applied to the sensor unit 100. The state of the sensor unit 100 may also include a change in the relative positions of the sensing chips 11, 21, and 31 (i.e., the distance between the sensing chips 11, 21, and 31). The state of communication between the sensing chips 11, 21, and 31 includes, for example, the strength of the transmission and reception signals between the sensing chips 11, 21, and 31.

[0028] Specifically, when vibrations are applied to the rail 203, which is the object to be measured, the intervals between the sensing chips 11, 21, and 31 change at a high frequency. The intervals between the sensing chips 11, 21, and 31 can be detected from the strength of the transmission and reception signals between the chips, and therefore, when it is detected that the intervals change at a frequency higher than a predetermined value, it can be detected that vibrations have been applied to the sensor unit 100. This makes it possible to detect vibrations applied to the rail 203 to which the sensor unit 100 is fixed. From the pattern of changes in this frequency and interval, it is possible to estimate the direction of the vibrations applied to the rail 203 (vibrations in the x direction or y direction).

[0029] Furthermore, when the pressure applied to the rail 203 changes, for example due to the load of a train, the rail 203 deforms and the spacing between the sensing chips 11, 21, and 31 changes gradually. Therefore, when a change in the spacing between the sensing chips 11, 21, and 31 is detected at a period lower than a predetermined value, the pressure applied to the rail 203 can be detected.

[0030] Furthermore, as the rail 203 thermally expands, the rail 203 deforms and the spacing between the sensing chips 11, 21, and 31 changes gradually. Therefore, if a change in the spacing between the sensing chips 11, 21, and 31 is detected at a period lower than a predetermined value, a change in the ambient temperature of the rail 203 can be detected.

[0031] The sensing chips 11, 21, and 31 have a rectangular plate-like outer shape. In the sensing chip 11, the transmitting coils 12, 22, and 32 are arranged to surround the outer periphery of the chip body and are approximately rectangular. The surfaces on which the transmitting coils 12, 22, and 32 are wound are parallel to the main surfaces of the sensing chips 11, 21, and 31. In the sensing chips 11, 21, and 31, the receiving coils 13, 23, and 33 are arranged to surround the outer periphery of the chip body and are approximately rectangular. The surfaces on which the receiving coils 13, 23, and 33 are wound are parallel to the main surfaces of the sensing chips 11, 21, and 31.

[0032] The power supply control unit 40 receives power from the secondary battery 120 and has the function of boosting and lowering voltage to operate the arithmetic circuits 16, 26, 36, etc. of the sensing chips 11, 21, 31. The arithmetic circuits 16, 26, 36 may be configured with a CPU, for example. The power supply control unit 40 may receive power from the backup battery 140 and has the function of selecting and controlling whether to use the secondary battery 120 or the backup battery 140.

[0033] The sensing chips 11, 21, and 31 are arranged close to each other, enabling wireless communication between the coils using magnetic field coupling. The above-described configuration of the sensing chips 11, 21, and 31 is formed on a semiconductor substrate and molded with resin to form an IC. The sensing chips 11, 21, and 31 and their coils can be miniaturized to a side length of approximately 300 μm, and the distance between the coils of adjacent chips can be reduced to approximately 40 μm.

[0034] 3, at least one of the sensing chips 11, 21, 31 may further include a temperature sensor. This allows for more accurate measurement of the temperatures around the sensing chips 11, 21, 31. Temperature information measured by the temperature sensor of the sensing chips 11, 21, 31 is transmitted to the outside via the communication module 50.

[0035] The sensing chip 31 is connected by wire to the communication module 50. A plurality of signals representing the sensing results measured by the sensing chips 11, 21, and 31 are transmitted to the communication module 50. The communication module 50 transmits the received sensing results to an external device, for example, a server 302. Therefore, the communication module 50 functions as a communication device for communicating with external devices. The communication distance of the communication module 50 is, for example, several meters to several tens of meters, which is longer than the communication distance achieved by magnetic field coupling. The server 302 receives and analyzes a plurality of signals representing the sensing results from the plurality of sensor units 100. The server 302 detects changes in the state of the rail 203, which is the object to be measured, based on the received signals.

[0036] In addition to the signals resulting from sensing, the sensing chips 11, 21, and 31 may also transmit to the server 302 information specific to the sensing chips 11, 21, and 31, such as the positions at which the sensing chips 11, 21, and 31 are located and identification information assigned to the sensing chips 11, 21, and 31. The positions, identification information, and the like may be stored in advance in the memories 18, 28, and 38, and read out by the arithmetic circuits 16, 26, and 36. The above-mentioned arithmetic results may also be output to the outside via multiple chips by sequentially transmitting and receiving the results between three or more adjacent chips in a so-called bucket brigade manner.

[0037] The server 302 displays the detected change in state of the object to be measured on the user interface 303 so that the user can visually recognize it.

[0038] 1, a plurality of sensor units 100 are fixed at predetermined intervals to a rail 203, which is the object to be measured. Therefore, by continuously observing information received from the plurality of sensor units 100 and integrating the plurality of data, it is possible to continuously measure the vibration, pressure, and environmental temperature acting on the rail 203, which is the object to be measured. This makes it possible to measure, for example, annual fluctuations in the shape of the rail 203, such as its length, and fluctuations in the distribution of pressure acting at various points on the rail 203.

[0039] FIG. 4 schematically illustrates a sensor unit 100a according to another embodiment. In the sensor unit 100 according to the first embodiment shown in FIG. 2, the sensing chips 11, 21, and 31 communicate with each other via magnetic field coupling or magnetic field resonance. In contrast, in the sensor unit 100a according to another embodiment, the sensing substrate 130 includes sensing chips 11a, 21a, and 31a, which are connected to each other via wires. Therefore, the sensing chips 11a, 21a, and 31a communicate with each other via wires, rather than via magnetic field coupling or magnetic field resonance. One or more of the semiconductor chips 11a, 11b, and 11c have a sensing function. Multiple signals representing the results of sensing measured by the sensing chips 11, 21, and 31 are transmitted via wires to the power supply control unit 40 and the communication module 50.

[0040] FIG. 5 schematically illustrates an energy harvesting device 110 according to the first embodiment. The energy harvesting device 110 generates power by energy harvesting. Energy harvesting is a technology that collects small amounts of unused energy from the surrounding environment, such as light, vibration, and heat, and converts it into power. Energy harvesting is also called energy harvesting. The energy harvesting device 110 according to this embodiment receives electromagnetic energy generated when a train 200 passes over a rail 203 and generates power. This electromagnetic energy may be electromagnetic wave noise or inverter noise. Electromagnetic wave noise may occur between the overhead wire 201 and pantograph 202 of the train 200. Inverter noise may occur when equipment in the train 200 is switched on and off.

[0041] As shown in Fig. 5, the energy harvesting device 110 has an antenna device 111 and a charging unit 114. The antenna device 111 has an antenna unit 112 and a rectifying circuit 113. Energy from the surrounding environment is received by the antenna unit 112, and the output of the antenna unit 112 is supplied to the rectifying circuit 113. The output of the rectifying circuit 113 is supplied to the charging unit 114. The secondary battery 120 shown in Fig. 2 is connected to the charging unit 114. Therefore, the secondary battery 120 is charged by the charging unit 114.

[0042] Returning to Figure 2, the power generated by the energy harvesting device 110 is stored in the secondary battery 120. The secondary battery 120 is a storage battery that stores the power generated by the energy harvesting device 110. Power for sensing is supplied from the secondary battery 120 to the sensing board 130. The sensing chips 11, 21, and 31 of the sensing board 130 operate on the power supplied from the secondary battery 120. In addition, a backup battery 140 is connected to the sensing board 130. The backup battery is a dry cell battery or the like, and is used as a backup when the energy harvesting device 110 is unable to generate power.

[0043] Fig. 6 is an explanatory diagram of electromagnetic energy 501 in the first embodiment. An arrow 500 in Fig. 6 indicates the direction of current flowing in the overhead wire 201. As shown in Fig. 6, the current 500 travels downward from the overhead wire 201, through the pantograph 202 and the train 200, and reaches the rail 203.

[0044] The electromagnetic energy 501, which is energy from the surrounding environment, includes energy due to electromagnetic noise generated when the train 200 travels on the rails 203. The electromagnetic noise is generated, for example, from the inverter (DC-AC conversion) or DC-DC voltage converter of the train 200 (hereinafter also referred to as inverter noise). The inverter noise includes a component in which high frequency waves generated by the inverter or the like are superimposed on the current 500 and flow through the rails 203, and a component that is radiated into the surrounding space as electromagnetic waves. The energy harvesting device 110 of the sensor unit 100 collects one or both of these components to generate electricity.

[0045] 7 and 8 show a first example of a method for fixing the sensor unit 100 to the rail 203 in the first embodiment. The first example is an example in which the energy harvesting device 110 of the sensor unit 100 collects electromagnetic noise 501 traveling on the rail 203. Fig. 7 shows a front view of the rail 203, and Fig. 8 shows a side cross-sectional view of the rail 203.

[0046] 7 and 8 , the sensor unit 100 is fixed to the side of the rail 203 using a strong magnet 150. The connection terminal 101 of the sensor unit 100 is connected to the rail 203 by an electric wire 161 via a connecting member 191. The sensor unit 100 collects components of electromagnetic energy 501 transmitted from the rail 203 by the electric wire 161. The connection terminal 102 of the sensor unit 100 is connected to gravel or the like by another electric wire 162, thereby earthing the sensor unit 100. Note that the connection terminal 101 of the sensor unit 100 may also be connected to the rail 203 via the magnet 150.

[0047] 9 and 10 show a second example of a method for fixing the sensor unit 100 to the rail 203 in the first embodiment. The second example is an example in which the energy harvesting device 110 of the sensor unit 100 collects electromagnetic energy 501 that propagates through space. Fig. 9 shows a front view of the rail 203, and Fig. 10 shows a side cross-sectional view of the rail 203.

[0048] As shown in FIGS. 9 and 10 , the sensor unit 100 is fixed to the side of the rail 203 using a powerful magnet 150. The sensor unit 100 has a metal conductor 170 that collects electromagnetic energy 501 radiated into space from the train 200. The metal conductor 170 and the connection terminal 101 of the sensor unit 100 are connected by an electric wire 163, and the sensor unit 100 receives the electromagnetic energy 501 collected by the metal conductor 170. Another electric wire 164 connects the connection terminal 102 of the sensor unit 100 to the rail 203 via a connecting member 192, thereby grounding the sensor unit 100. Note that the electric wire 163 may be connected to the metal conductor 170 inside the housing of the sensor unit 100. The electric wire 164 may also be connected to the magnet 150 inside the housing of the sensor unit 100. In this manner, grounding via the magnet 150 is possible.

[0049] The rails 203 are very large conductors, and in addition, very large noise is generated when the train 200 passes over the rails 203. The energy harvesting device 110 can generate a large amount of power by collecting such noise from the sensing target.

[0050] Furthermore, when the train 200 passes over the rails 203, the vibration and position of the rails 203 change significantly. Therefore, it is possible to determine when the energy harvesting device 110 generated a large amount of power.

[0051] Since the train 200 passes over the rails 203 periodically, the energy harvesting device 110 can generate a large amount of power periodically, and therefore can perform sensing continuously while continuing to supply the power required for sensing.

[0052] 11 is a schematic diagram of a sensor system 401 according to the second embodiment. In the second embodiment, components common to those in the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted. In the first embodiment, the sensor unit 100 is fixed to the rail 203, but in the second embodiment, the sensor unit 100 is fixed to a sleeper 204 below the rail 203.

[0053] 12 and 13 show an example of a method for fixing the sensor unit 100 to the sleeper 204 in the second embodiment. In this example, the energy harvester 110 of the sensor unit 100 collects electromagnetic energy 501 emitted into space. Fig. 12 shows a front view of the sleeper 204, and Fig. 13 shows a side cross-sectional view of the sleeper 204.

[0054] As shown in Figures 12 and 13, the sensor unit 100 is fixed to a fixing metal plate 180 using a powerful magnet 150, and the fixing metal plate 180 is fixed to a sleeper 204. As shown in Figures 12 and 13, an electric wire 165 connects the connection member 101 of the sensor unit 100 to the fixing metal plate 180 via a connecting member 194. The fixing metal plate 180 collects electromagnetic energy 501 emitted into space from the train 200. Therefore, the fixing metal plate 180 also functions as a collecting metal plate. The sensor unit 100 receives the electromagnetic energy 501 transmitted from the fixing metal plate 180 via the electric wire 165. Another electric wire 166 connects the connection terminal 101 of the sensor unit 100 to the sleeper 204 via a connecting member 193, thereby earthing the sensor unit 100. The electric wire 165 may be connected from inside the housing of the sensor unit 100 to the fixing metal plate 180 via the magnet 150 .

[0055] The train 200 passes over the sleepers 204. When passing, the train 200 is on the sleepers 204 and is in close proximity to the sleepers 204. Therefore, the sensor unit 100 can collect energy from electromagnetic noise generated when the train 200 runs on the rails 203.

[0056] According to the sensor systems 400 and 401 of the first and second embodiments, sensing is performed using the power generated by the energy harvesting device 110. This makes it possible to detect continuous vibrations, pressure changes, or temperature changes in the rails 203 or sleepers 204 of the train 200 without requiring an external power supply.

[0057] The technical scope of the present invention also includes a sensing method for implementing the sensor systems 400 and 401 of the first and second embodiments. The sensing method includes an energy harvesting stage in which the energy harvesting device 110 mounted on the sensing board 130 generates power using energy present in the environment in which it is installed, and a stage in which a sensor mounted on the sensing board 130 receives the power generated by the energy harvesting stage and performs sensing.

[0058] FIG. 14 schematically illustrates a sensor system 402 according to the third embodiment. The object to be measured may be, for example, a road 205 for a vehicle 206 or a road joint used at a connection point of a highway. When the object to be measured is the road 205 for a vehicle 206 as shown in FIG. 14 , the sensor unit 100 is attached to the road 205 for the vehicle 206. When the vehicle 206 travels on the road 205, current flows between the battery, inverter, and motor within the vehicle 206, generating inverter noise, which is electromagnetic energy 501. The sensor unit 100 receives this inverter noise, generates power using the energy harvesting device 110, and senses the state of the road 205.

[0059] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. Furthermore, it will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0060] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order.

[0061] REFERENCE SIGNS LIST 11, 11a Sensing chip, 12 Transmitting coil, 13 Receiving coil, 14 Transmitting conversion circuit, 15 Receiving conversion circuit, 16 Arithmetic circuit, 17 Power supply, 18 Memory unit, 21, 21a Sensing chip, 22 Transmitting coil, 23 Receiving coil, 24 Transmitting conversion circuit, 25 Receiving conversion circuit, 26 Arithmetic circuit, 27 Power supply, 28 Memory unit, 31, 31a Sensing chip, 32 Transmitting coil, 33 Receiving coil, 34 Transmitting conversion circuit, 35 Receiving conversion circuit, 36 Arithmetic circuit, 37 Power supply, 38 Memory unit, 40 Power supply control unit, 50 Communication module, 100 Sensor unit, 101, 102 Connection terminal, 110 Energy harvesting device, 111 Antenna device, 112 Antenna unit, 113 Rectifier circuit, 114 Charging unit, 120 Secondary battery, 130 Sensing board, 140 Spare battery, 150 Magnet, 161 Electric wire, 162 Electric wire, 163 Electric wire, 164 Electric wire, 165 Electric wire, 166 Electric wire, 170 Metal conductor, 180 Fixing metal plate, 191, 192, 193, 194 Connection member, 200 Train, 201 Overhead line, 202 Pantograph, 203 Rail, 204 Sleeper, 205 Road, 206 Vehicle, 300 Information processing unit, 301 Base station, 302 Server, 303 User interface, 400, 401, 402 Sensor system, 500 Current, 501 Electromagnetic energy

Claims

1. A sensor unit fixed to a path along which a moving body moves, the sensor unit comprising: an energy harvesting device that generates electricity using electromagnetic energy emitted into the surrounding environment when the moving body passes through the path; and a sensor that receives and senses the power generated by the energy harvesting device.

2. The sensor unit of claim 1, further comprising a sensing board on which the sensor is mounted, the sensing board comprising an arithmetic circuit and a communication device that operate on power generated by the energy harvesting device, the arithmetic circuit performing arithmetic processing on the sensing results, and the communication device communicating the sensing results with an external device.

3. The sensor unit according to claim 1, wherein the moving body is a train and the moving path is a rail.

4. The sensor unit according to claim 1, wherein the moving body is a vehicle and the travel path is a road for the vehicle.

5. The sensor unit according to claim 1, wherein the sensor includes a plurality of sensing chips, and the plurality of sensing chips communicate with each other by magnetic field coupling or magnetic field resonance.

6. The sensor unit according to claim 1, wherein the electromagnetic energy is electromagnetic wave noise or inverter noise.

7. The sensor unit of claim 1, wherein said electromagnetic energy is collected from said path of travel.

8. The sensor unit of claim 1, wherein the electromagnetic energy is collected from a space in the environment.

9. The sensor unit according to claim 1, further comprising: a fixing metal plate for fixing the sensor unit to the movement path; and a magnet for fixing the sensor unit to the fixing metal plate.

10. The sensor unit according to claim 1, further comprising a storage battery that stores the power generated by the energy harvesting device.

11. The sensor unit of claim 1, wherein the sensor senses the path of movement by detecting at least one of vibrations, pressure changes, or temperature changes around the sensor unit as the moving object passes by.

12. A sensor system comprising: a sensor unit according to any one of claims 1 to 11; and a server that receives and analyzes the sensing results from the sensor unit.

13. A sensing method for sensing using a sensor unit fixed to a path along which a moving body moves, comprising: an energy harvesting stage for generating electricity using electromagnetic energy emitted into the surrounding environment as the moving body passes through the path; and a stage for receiving the power generated by the energy harvesting stage and sensing the state of the path.

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