Electric Field Detection System

Abstract

To enable accurate detection of the electric field conditions at low cost in consideration of an influence of static electricity accumulated by a vehicle.SOLUTION: An electric field detection system comprises an electric field sensor 12 mounted in a vehicle 11 to detect information on an electric field in a space the vehicle is located 11 in, and an electric field intensity acquisition unit 19 configured to acquire electric field intensity in the space the vehicle 11 is located in based on the information on the electric field detected by the electric field sensor 12. The electric field intensity is corrected according to information on static electricity accumulated by the vehicle 11 while the vehicle 11 is on the move.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electric field sensing system. [Background technology]

[0002] For example, a stable power supply is necessary in facilities that require stable operation, such as semiconductor manufacturing plants.However, natural phenomena such as lightning strikes can damage power lines and other power equipment, inevitably causing power outages and voltage drops (instantaneous voltage drops).

[0003] Patent Document 1 describes a system for predicting the occurrence of lightning strikes and issuing warnings to facilities. Specifically, the system described in this patent document installs a lightning strike detection device at the construction site of a structure such as a tower or at a location in the vicinity of the construction site, and an electrostatic field detection device at the construction site of the structure or at a location nearby the construction site. The lightning strike detection device detects the occurrence of a lightning strike, and the electrostatic field detection device detects the electric field strength of the electrostatic field between the cloud and the ground. Based on the levels of the detection signals output from both detection devices, a warning output device determines a rank for the warning information and outputs the ranked warning information. In this case, the detection level of the electrostatic field detection device is given priority when outputting the warning information.

[0004] In manufacturing plants, various installed equipment is electrically controlled and electrically networked, making it important to take measures (lightning damage countermeasures) to protect not only against direct damage, such as damage to equipment caused by lightning strikes on the facility, but also against indirect damage, such as power outages and voltage drops. Semiconductor factories, in particular, are susceptible to the aforementioned effects, and therefore require more accurate lightning strike predictions than ever before. For example, in order to improve the accuracy of lightning strike predictions in the system described in Patent Document 1, it is conceivable to increase the number of electrostatic field detectors and install them over a wider area. However, increasing the number of detectors leads to higher equipment costs, making it unrealistic to offer lightning strike predictions to other parties (factories, etc.) as a paid service.

[0005] Therefore, the present applicant has proposed a new electric field detection system in Japanese Patent Application No. 2021-48863. That is, this detection system is an electric field detection system including a field effect transistor, an antenna connected to the gate electrode of the field effect transistor, and a bias power supply for applying a predetermined voltage between the source electrode and the drain electrode of the field effect transistor, and is characterized in that the antenna is a metal part of the body of the vehicle.

[0006] The electric field detection system configured as described above can detect the state of the electric field by utilizing the characteristics of a field-effect transistor, so the state of the received electric field can be detected with high accuracy. Furthermore, by using the antenna as a metal part of the vehicle body, the electric field can be detected over a very large area, making it possible to detect the state of the electric field with high sensitivity. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-250211 Summary of the Invention [Problem to be solved by the invention]

[0008] However, when actually attempting to detect the electric field strength in the space in which the vehicle is located using the vehicle's metal body as an antenna, the influence of static electricity carried by the vehicle cannot be ignored. In other words, since most of the vehicle is made of metal, it is thought that the vehicle is charged with a non-negligible amount of static electricity. Therefore, when detecting the electric field strength using the vehicle's metal body as an antenna as described above, it is highly likely that the detected electric field strength will be influenced by the static electricity. This makes the detection system, which is theoretically capable of high-precision detection, impractical.

[0009] Of course, the problems mentioned above do not only apply to lightning strike predictions, but can also occur when predicting other phenomena that could become natural disasters from the state of electric fields.

[0010] In view of the above circumstances, the technical problem to be solved in this specification is to be able to detect the state of an electric field accurately and at low cost, taking into account the influence of static electricity carried by a vehicle. [Means for solving the problem]

[0011] The above-mentioned problems are solved by an electric field detection system according to the present invention. That is, this detection system is an electric field detection system for detecting electric field strength in a space in which a vehicle is located, and is characterized in that it includes an electric field sensor provided in the vehicle and detecting information about the electric field in the space in which the vehicle is located, and an electric field strength acquisition unit that acquires the electric field strength in the space in which the vehicle is located based on the information about the electric field detected by the electric field sensor, and is configured so that the electric field strength is corrected based on information about static electricity carried by the vehicle while the vehicle is traveling.

[0012] The present invention takes into account the fact that static electricity is primarily generated when a vehicle is traveling. Specifically, static electricity generated on a vehicle is believed to be primarily generated by friction between the tires and the road surface, friction between the vehicle body surface and the air, and friction between elements in the vehicle drivetrain and power transmission system. Because these frictions all occur when the vehicle is traveling, correcting the electric field strength acquired by the electric field sensor and the electric field strength acquisition unit based on information about the static electricity carried by the vehicle while traveling cancels the effects of static electricity and enables highly accurate detection of the electric field strength. Of course, the electric field detection system of the present invention can detect the electric field strength according to the position of the traveling vehicle, so a single electric field sensor can essentially detect the electric field strength at multiple points. Therefore, it is possible to detect the electric field strength over a wide area without using a large number of electric field sensors, enabling low-cost detection of the electric field strength.

[0013] In the electric field detection system according to the present invention, the information relating to static electricity carried by the vehicle may include at least the electric field strength acquired by the electric field strength acquisition unit on a sunny or cloudy day.

[0014] In this way, if the electric field strength is acquired by the electric field strength acquisition unit on a sunny or cloudy day, it is possible to eliminate the influence of the electric field generated by the approach of a thundercloud and evaluate only information related to the static electricity charged to the vehicle as the vehicle is traveling. Therefore, with this configuration, it is possible to accurately detect the magnitude of the static electricity carried by the vehicle.

[0015] In this case, in the electric field detection system according to the present invention, the information about the static electricity carried by the vehicle may further include the humidity of the space in which the vehicle is located at the time the electric field strength is acquired.

[0016] The static electricity carried by a vehicle is also affected by, for example, the humidity of the space in which the vehicle is located. That is, the higher the humidity, the less static electricity the vehicle carries, and the lower the humidity, the more static electricity the vehicle carries. Therefore, by correcting the electric field strength by taking into account the humidity when the electric field strength is acquired as described above, it is possible to accurately detect the amount of static electricity carried by the vehicle.

[0017] In the electric field detection system according to the present invention, the information about the static electricity carried by the vehicle may further include information about the vehicle model.

[0018] The static electricity carried by a vehicle is affected by, for example, the vehicle model. That is, the drivetrain and power transmission system, which are sources of static electricity, differ depending on the vehicle model, and the amount of static electricity generated by the operation of these drivetrain and power transmission systems also differs depending on the vehicle model. Therefore, by correcting the electric field strength taking into account the vehicle model from which the electric field strength was obtained, it is possible to accurately detect the magnitude of static electricity carried by the vehicle. [Effects of the Invention]

[0019] As described above, the electric field detection system according to the present invention can accurately and inexpensively detect the state of an electric field while taking into account the effect of static electricity carried by a vehicle. This also makes it possible to realize highly accurate lightning strike predictions at low cost. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a conceptual diagram of a lightning strike prediction system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view of a vehicle for explaining the configuration of the electric field detection system shown in FIG. [Figure 3] 2 is a flowchart showing an example of a prediction method using the prediction system shown in FIG. 1. [Figure 4] 10 is a flowchart showing a detailed procedure of a static electricity information acquisition step. [Figure 5] FIG. 2 is a conceptual diagram showing an example of a manner in which data relating to static electricity is communicated between each vehicle and a data processing device. [Figure 6] 10 is a flowchart showing detailed procedures of a lightning strike occurrence prediction processing step. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an electric field detection system according to one embodiment of the present invention and a lightning strike prediction system including the detection system will be described with reference to the drawings.

[0022] 1 shows a conceptual diagram of a lightning strike prediction system 10 according to this embodiment. This prediction system 10 includes electric field strength detection devices 12 installed in a plurality of vehicles 11, vehicle position information acquisition devices 13, and data processing devices 14. In this case, the electric field strength detection devices 12 and data processing devices 14 constitute an electric field detection system according to the present invention. Each component will be described in detail below.

[0023] The electric field strength detection device 12 is provided in all vehicles 11 from which electric field strength data, which will be described later, is to be acquired, and in this embodiment, for example, as shown in Fig. 2, includes a field effect transistor (FET) 15, an antenna 16 connected to a gate electrode 15a of the field effect transistor 15, and a bias power supply 17 capable of applying a predetermined voltage V1 between a source electrode 15b and a drain electrode 15c of the field effect transistor 15. In this embodiment, the electric field strength detection device 12 further includes a measurement device 18 for measuring the magnitude of a current I flowing between the source electrode 15b and the drain electrode 15c, and an electric field strength calculation unit 19. In this case, the electric field strength detection device 12 corresponds to the electric field sensor according to the present invention, and the electric field strength calculation unit 19 corresponds to the electric field strength acquisition unit according to the present invention.

[0024] As the field effect transistor (FET) 15, any type of field effect transistor (junction FET, MOSFET, etc.) can be used as long as the ease of flow of the current I (current amount) changes depending on the magnitude of the voltage V2 applied to the gate electrode 15a, as will be described later, in other words, as long as the value of the current I can be converted into the voltage V2 and thus into the state of the electric field (for example, the electric field strength) that can be received by the antenna 16. In this embodiment, a MOSFET is used as the field effect transistor 15.

[0025] The antenna 16 is configured to receive an electric field near the ground surface where the vehicle 11 is located, and to apply a voltage V2 corresponding to the state of the received electric field to the gate electrode 15a. For example, in this embodiment, the antenna 16 is configured so that the magnitude of the voltage V2 applied to the gate electrode 15a is proportional to the strength of the received electric field (electric field intensity).

[0026] In this embodiment, the antenna 16 having the above configuration is configured as a metal body part of the vehicle 11. In this embodiment, the antenna 16 is configured as a door outer 11a of the vehicle 11, as shown in Fig. 2. That is, by electrically connecting the gate electrode 15a of the field effect transistor 15 to the door outer 11a, which is a metal outer plate of the vehicle 11, by a conductor or the like, the door outer 11a can function as the main body of the antenna 16.

[0027] In this case, the connection point of the gate electrode 15a to the door outer 11a is arbitrary in principle, but considering the vertical bias of charges in the electric field near the ground surface, it is preferable to connect the gate electrode 15a to one side in the vertical direction of the door outer 11a. In this embodiment, as shown in Figure 2, the gate electrode 15a is connected to the lower part of the door outer 11a.

[0028] Any power supply can be used as the bias power supply 17. For example, it is preferable in terms of cost to use an existing power supply installed in the vehicle 11, such as a power supply for the ECU of the vehicle 11.

[0029] The measuring device 18 is configured by, for example, an ammeter, and is provided at a position where it can measure the magnitude (current value) of the current I flowing between the source electrode 15b and the drain electrode 15c of the field effect transistor 15. The measuring device 18 transmits information about the measured current value to the electric field intensity calculation unit 19. The current value is measured by the measuring device 18, for example, at regular time intervals. Of course, the measuring device 18 may also measure the current value each time it receives a command from the data processing device 14.

[0030] The field strength calculation unit 19 is configured to be able to calculate the state of the electric field (here, the field strength) around the vehicle 11, more precisely around the antenna 16, based on information about the current value measured by the measurement device 18. Furthermore, the field strength calculation unit 19 transmits information about the calculated field strength to the data communication device 20 provided in the vehicle 11. In this case, the field strength calculation unit 19 may transmit information about all of the calculated field strengths to the data communication device 20, or may transmit only information about field strengths equal to or greater than a preset threshold to the data communication device 20.

[0031] The data communication device 20 is configured to be able to transmit at least the electric field strength data, data relating to the position information of the vehicle 11, humidity data of the space where the vehicle 11 is located, and data relating to the acquisition time of each piece of data to the data processing device 14. In this case, the humidity data may be measured by a hygrometer 21 provided on the vehicle 11, as shown in FIG. 2. Of course, data relating to weather other than the above, that is, data relating to the weather in the area where the vehicle position data was acquired, may also be transmitted, and is configured to be able to transmit information relating to phenomena generally recognized as weather information, such as humidity, rainfall amount (including whether it is raining or not), rainfall area, snowfall amount, snowfall area, wind speed, wind volume, and air pressure. Furthermore, this weather data may be data measured directly by various measuring instruments, or may be data obtained by indirect calculation from data relating to operations related to the natural phenomenon, such as the number of windshield wiper operations.

[0032] A wide range of existing devices capable of data communication can be applied as the data communication device 20. For example, a data communication device dedicated to the data communication according to this embodiment may be installed and fixed in the vehicle 11 as the data communication device 20. Alternatively, a general-purpose data communication terminal such as a tablet or smartphone with a dedicated app installed may be installed in the vehicle 11 and used as the data communication device 20.

[0033] Vehicle position information acquisition device 13 is configured as a receiving unit of a satellite positioning system that enables communication with satellites (positioning satellites) for a satellite positioning system such as GPS. In this case, vehicle position information acquisition device 13 is configured as, for example, a car navigation system. Vehicle position information acquisition device 13 acquires (calculates) the position of vehicle 11 by communicating with the positioning satellite, and transmits the acquired position information of vehicle 11 to data communication device 20 as position data of vehicle 11. Data communication device 20 that receives the position data is capable of transmitting the position data to data processing device 14 together with the above-mentioned electric field strength data and weather data. Of course, vehicle position information acquisition device 13 may be provided in vehicle 11 as a dedicated device separate from the car navigation system.

[0034] As shown in FIG. 1, the data processing device 14 includes a data storage unit 22 and a data processing unit 23. The data storage unit 22 stores position data, electric field strength data, data related to static electricity carried by each vehicle 11, and meteorological data for the space in which each vehicle 11 is located (weather data other than the data described above) transmitted from the multiple vehicles 11. These data are transmitted, for example, from each vehicle 11 at predetermined time intervals. Furthermore, if there is data transmitted from a source other than the vehicle 11, this data is stored in the data storage unit 22. In the example shown in FIG. 1, meteorological data provided by a meteorological information provider 24 is received and stored in the data storage unit 22. This meteorological data includes, for example, data related to actual lightning strikes (such as region, time, and strength). Alternatively, in addition to data related to actual lightning strikes, meteorological data for the area in which each vehicle is located (such as weather and humidity) is also included.

[0035] The data processing unit 23 executes a process for predicting the occurrence of a lightning strike based on various data transmitted by the data communication device 20 and stored in the data storage unit 22.

[0036] Here, the lightning strike occurrence prediction process (specifically, the execution of a program for predicting the occurrence of lightning strikes) can be performed using, for example, AI (artificial intelligence). Specifically, first, using various data accumulated in the data accumulation unit 22 as training data, the data processing unit 23 generates a learning model that outputs information regarding the area, time, and strength of lightning strikes (learning model generation step P1). The training data used here includes the position data and electric field strength data of each vehicle 11 and data related to actual lightning strikes (hereinafter simply referred to as lightning strike data). In other words, the position data and electric field strength data corresponding to past lightning strike data, i.e., the electric field strength data for the area and time when the lightning strike actually occurred, are extracted from the various data accumulated in the data accumulation unit 22 using the corresponding position data. Then, a learning model is generated that uses the extracted electric field strength data and other weather data as input and outputs lightning strike data. For the lightning strike data, for example, data related to past lightning strikes from weather data provided by a weather information provider 24 can be used, as shown in FIG. 1.

[0037] After generating a learning model for the occurrence of lightning strikes in this way, the occurrence of lightning strikes is predicted using this learning model (lightning strike occurrence prediction step P2). Specifically, the data processing unit 23 executes a program that inputs the position data, electric field strength data, and other meteorological data of each vehicle 11 into the learning model generated in the learning model generation step, and outputs at least one of the area, time, and intensity of the lightning strike as a predicted result of the lightning strike occurrence. In this way, information regarding the lightning strike occurrence prediction result is obtained.

[0038] Next, an example of a lightning strike occurrence prediction method using the lightning strike occurrence prediction system 10 configured as described above will be described with reference to FIGS.

[0039] 3 shows a flowchart for explaining the steps of a lightning strike occurrence prediction method using the lightning strike occurrence prediction system 10. As shown in this flowchart, the lightning strike occurrence prediction method according to this embodiment includes a static electricity information acquisition step S1 for acquiring information (data) about static electricity carried by each vehicle 11, a first data acquisition step S2 for acquiring field strength data, position data, and weather data from each vehicle 11, a second data acquisition step S3 for acquiring weather data from sources other than the vehicles 11, a lightning strike occurrence prediction step S4 for predicting the occurrence of a lightning strike based on the various acquired data, and a lightning strike occurrence prediction information provision step S5 for providing information about the lightning strike occurrence prediction result to necessary facilities 25 (for example, various production facilities such as semiconductor factories) based on the lightning strike occurrence prediction result, if necessary.

[0040] (S1) Electrostatic information acquisition step In this step, information about static electricity carried by each of the target vehicles 11 is acquired from the multiple vehicles 11. In this embodiment, predetermined data related to static electricity is acquired in accordance with the flowchart shown in FIG. 4. In this step S1, first, it is determined whether the space in which the vehicle 11 is located is sunny or cloudy (weather determination step S11). If it is determined that the space is sunny or cloudy, it is determined whether the vehicle 11 is currently (was) traveling or not (traveling state determination step S12). If it is determined that the vehicle 11 is (was) traveling, data related to static electricity carried by the vehicle 11 while the vehicle 11 is traveling, here, field strength data, humidity data, and vehicle type data, are acquired (static electricity data acquisition step S13).

[0041] In the weather determination step S11, the determination of whether the space in which the vehicle 11 is located is sunny or cloudy may be performed by an arithmetic and memory device such as an ECU provided in the vehicle 11, or may be performed by the data processing device 14. When performed by an arithmetic and memory device provided in the vehicle 11, for example, a measuring device capable of measuring sunny weather-related phenomena as numerical values, such as a sunshine meter (not shown), may be provided in the vehicle 11 to determine whether the weather is sunny or cloudy, or a sensor that detects the operating state of a device that operates depending on the weather, such as windshield wipers, may be used to determine whether the weather is sunny or cloudy. Alternatively, when performed by the data processing device 14, the determination of whether the weather is sunny or cloudy may be performed based on weather information for the area in which the vehicle 11 is located, provided by the weather information providing agency 24.

[0042] Furthermore, in the traveling state determination step S12, the determination of whether the vehicle 11 is (was) traveling at present or until just before may be performed by various measuring devices or an arithmetic and memory device such as an ECU provided in the vehicle 11. Furthermore, if it is determined that the vehicle 11 is traveling, the condition for performing the static electricity data acquisition step S13 may be that the speed of the vehicle 11 is equal to or greater than a certain magnitude, or that a predetermined time has elapsed since the start of traveling. If a predetermined time has elapsed since the start of traveling, the amount of static electricity accumulated in the vehicle 11 tends to converge to a certain value as the vehicle 11 begins traveling, and therefore, it becomes possible to acquire highly accurate and stable static electricity-related data (electric field strength data as static electricity) in the next step S13.

[0043] Furthermore, in static electricity data acquisition step S13, the electric field strength data is detected (acquired) by the electric field strength detection device 12. The humidity data is acquired by the hygrometer 21. Furthermore, the vehicle type data is acquired by an existing or new arithmetic and memory device in the vehicle 11. Note that, if it is determined in the running state determination step S12 that the vehicle was running immediately before, the amount of static electricity reduction may be estimated according to the elapsed time since the vehicle stopped, and this may be reflected in the detected electric field strength data.

[0044] The processing relating to the series of steps S11 to S13 described above may be performed, for example, periodically, or at any timing based on an instruction from the data processing device 14. Alternatively, the processing may be performed at a timing determined by the vehicle 11 depending on the traveling state of the vehicle 11.

[0045] The various data relating to static electricity acquired as described above is transmitted to the data processing device 14 by the data communication device 20 (see FIG. 5). The data processing device 14 receives the various data and stores the received data in the data storage unit 22. In this way, data relating to static electricity carried by each target vehicle 11 while the vehicle 11 is traveling is acquired. These various data can be stored as big data in a linked state.

[0046] (S2) First data acquisition step In this step, position data, electric field strength data, and meteorological data such as temperature, rainfall, and wind speed (hereinafter referred to as first meteorological data for convenience) of each vehicle 11 are acquired from the multiple vehicles 11 from which data is to be acquired. Specifically, the electric field strength detection device 12 detects the electric field strength in the space where the vehicle 11 is located, and information about the detected electric field strength is transmitted as electric field strength data to the data processing device 14 by the data communication device 20. Similarly, position information of the vehicle 11 acquired by the vehicle position information acquisition device 13 is transmitted as position data to the data processing device 14 by the data communication device 20. Furthermore, meteorological information about the space where the vehicle 11 is located, detected by various sensors (not shown), etc., is transmitted as first meteorological data to the data processing device 14 by the data communication device 20. The data processing device 14, which has received these various data, stores the received various data in the data storage unit 22. In this way, electric field strength data and first meteorological data at a predetermined time for multiple locations within a predetermined area are acquired.

[0047] (S3) Second data acquisition step In this step, weather data (hereinafter referred to as second weather data for convenience) including data on lightning strikes that have occurred in the past within a specified area (lightning strike data) is acquired from the weather information provider 24. The data processing device 14 accumulates the acquired weather data (second weather data) such as the lightning strike data in the data accumulation unit 22. As a result, the lightning strike data for a specified time within a specified area, the electric field strength data for the same area and at the same time, and various weather data are accumulated in the data accumulation unit 22 in a mutually associated state. Note that the timing of the first data acquisition step S2 and the second data acquisition step S3 are both arbitrary, and as shown in FIG. 3, the order in which the second data acquisition step S3 and the first data acquisition step S2 are performed is not limited.

[0048] (S4) Lightning strike prediction step In this step, the data processing unit 23 performs a process for predicting the occurrence of a lightning strike within a predetermined area based on the various data acquired in steps S1 to S3. Specifically, as shown in FIG. 6, first, it is determined whether or not the space in which the vehicle 11, from which the field intensity data acquired in step S2 was obtained, is located is rainy (rainy weather determination step S41). If it is determined that the weather is not rainy, the field intensity data acquired in step S2 is corrected based on the various data related to static electricity acquired in step S1 (correction step S42). That is, the field intensity data corresponding to the vehicle type and humidity data of the vehicle 11 from which the field intensity data acquired in step S2 was obtained is extracted from the data storage unit 22, and the field intensity data is treated as data related to static electricity (noise data, so to speak) and subtracted from the field intensity data acquired in step S2 for correction. Then, the data processing unit 23 inputs various data including the corrected field intensity data and executes a program that outputs a lightning strike occurrence prediction result (prediction process execution step S43).

[0049] Alternatively, if it is determined in the rainy weather determination step S41 that it is raining, the data processing unit 23 executes a program that inputs various data including the electric field strength data acquired in step S2 without correcting the data, and outputs the result of predicting the occurrence of lightning strikes.

[0050] In the rainy weather determination step S41, the determination of whether or not it is raining in the space where the vehicle 11 is located may be performed by an arithmetic and memory device such as an ECU provided in the vehicle 11, or may be performed by the data processing device 14. When performed by an arithmetic and memory device provided in the vehicle 11, for example, a sensor that detects the operating state of the wipers (not shown) may be used to determine whether or not it is raining. Alternatively, when performed by the data processing device 14, the determination of whether or not it is raining may be based on weather information for the area where the vehicle 11 is located, provided by the weather information providing agency 24.

[0051] In addition, in the field strength data correction step S42, the correction process of the field strength data may be performed by various measuring devices or calculation storage devices such as an ECU provided in the vehicle 11, or may be performed by the data processing device 14.

[0052] In addition, in the prediction process execution step S43, any program can be executed, and in this embodiment, a lightning strike occurrence prediction program using the above-mentioned learning model is executed. That is, in the learning model generation step P1, a learning model for lightning strike occurrence is generated using the past electric field strength data, location data, weather data, and lightning strike data acquired in steps S2 and S3 as training data. Thereafter, the electric field strength data, location data, and weather data acquired at a predetermined time are input into the learning model, and the data processing unit 23 executes a program that outputs at least one of the area, time, and intensity of lightning strikes that will occur after the predetermined time as a lightning strike occurrence prediction result. This allows information about the lightning strike occurrence prediction result after the predetermined time to be acquired.

[0053] (S5) Prediction information provision step In this step, information about the lightning strike occurrence prediction result acquired in step S4 is provided to the facility 25 that needs it. In this way, the lightning strike occurrence prediction information can be utilized in the facility 25 that needs it (for example, to implement advance measures against lightning strikes, including determining whether or not they are possible).

[0054] As described above, in the electric field detection system according to this embodiment, the electric field strength acquired by the electric field strength detection device 12 and the electric field strength calculation unit 19 is corrected based on information about static electricity carried by the vehicle 11 while the vehicle 11 is traveling, thereby canceling the influence of static electricity and enabling highly accurate detection of the electric field strength. Of course, with the electric field detection system according to the present invention, the electric field strength can be detected according to the position of the traveling vehicle 11, so that one electric field strength detection device 12 can essentially detect the electric field strength at multiple points. Therefore, it is possible to detect the electric field strength over a wide area without using so many electric field strength detection devices 12, and it is possible to detect the electric field strength at low cost.

[0055] Furthermore, in this embodiment, the electric field strength obtained by the electric field strength calculation unit 19 on a sunny or cloudy day is acquired as data related to static electricity, so that it is possible to eliminate the influence of an electric field generated by the approach of a thundercloud and evaluate only the static electricity charged to the vehicle 11 due to the vehicle 11 traveling. Therefore, with this configuration, it is possible to accurately detect the magnitude of static electricity carried by the vehicle 11.

[0056] In addition, in this embodiment, the electric field strength is corrected by taking into consideration the humidity of the space in which the vehicle 11 is located at the time the electric field strength is acquired and information about the vehicle model of the vehicle 11, thereby making it possible to more accurately detect the magnitude of static electricity carried by the vehicle 11.

[0057] In this embodiment, the electric field (here, electric field strength) in the space in which the vehicle 1 is located can be detected using the electric field strength detection device 12, which includes a field-effect transistor 15, an antenna 16, and a bias power supply 17. When the antenna 16 receives the electric field in the space in which the antenna 16 is placed, a voltage V2 corresponding to the state of the received electric field (electric field strength) is applied to the gate electrode 15a. Since a certain correlation is observed between the electric field strength and the voltage V2 (gate voltage) applied to the gate electrode 15a, the electric field strength around the vehicle 11 can be accurately detected by accurately evaluating the fluctuation in the current I between the source electrode 15b and the drain electrode 15c that occurs when the voltage V2 is applied to the gate electrode 15a. Here, by placing the antenna 16 of the electric field strength detection device 12 on a metal body part of the vehicle 11, specifically the outer door panel 11a, the electric field can be detected over a very large area. This allows for sensitive detection of the electric field strength, making it possible to predict the occurrence of a lightning strike with greater accuracy. Furthermore, the field effect transistor 15 is very inexpensive and easy to obtain, and by using a metal body part of the vehicle 11 (here, the outer door panel 11a) as the antenna 16, it is possible to reduce the effort and cost of preparing a separate antenna 16. Furthermore, the bias power supply 17 can utilize an existing power supply (such as an ECU power supply) installed in the vehicle 11, which also makes it possible to manufacture the electric field intensity detection device 12 at low cost.

[0058] Furthermore, according to the lightning strike prediction system 10 of this embodiment, in addition to the highly accurate electric field detection capability of the above-described electric field strength detection device 12, by acquiring electric field strength data and position data from multiple vehicles 11, it is possible to acquire a large amount of electric field strength data over an extremely wide area while linking it to the position data. Therefore, by predicting the occurrence of a lightning strike based on this large amount of electric field strength data, it is possible to achieve lightning strike predictions with significantly higher reliability than conventional lightning strike warning techniques. Furthermore, this position data and electric field strength data can be collected (stored) by using the data communication device 20 already installed in the vehicle 11, so it is possible to build the above-described prediction system 10 without incurring a significant increase in cost. Furthermore, as in the present invention, information regarding the static electricity carried by vehicle 11 while the vehicle 11 is traveling can be collected (stored) as data regarding static electricity obtained by each vehicle 11 (electric field strength data on sunny or cloudy days, humidity data, vehicle type data). Therefore, by utilizing this data as big data, it is possible to appropriately correct the electric field strength data by using the data regarding static electricity stored in the data storage unit 22, without necessarily having to obtain information regarding the static electricity carried by vehicle 11 on each vehicle 11 side.

[0059] Furthermore, in this embodiment, the data processing unit 23 acquires from the vehicle 11 location data, electric field strength data, and data relating to meteorological information for the area in which the location data was acquired, and also acquires meteorological data including data relating to lightning strikes that have actually occurred from the meteorological information provider 24, and predicts the occurrence of lightning strikes based on the various acquired data, thereby enabling even more accurate lightning strike predictions.

[0060] The above describes one embodiment of the present invention, but the electric field detection system according to the present invention and the lightning strike prediction system equipped with this detection system can also have configurations other than those described above, as long as they do not deviate from the spirit of the invention.

[0061] For example, in the above embodiment, the case where the static electricity information acquisition step S1 is executed by the data processing device 14 has been exemplified, but of course the present invention is not limited to this. For example, some or all of the steps S11 to S13 constituting the static electricity information acquisition step S1 may be executed by an arithmetic processing device on the vehicle 11 side. In this case, the corrected field strength data is transmitted by the data communication device 20 to the data processing device 14, and therefore the corrected field strength data can be accumulated (stored) in the data accumulation unit 22.

[0062] For example, in the above embodiment, an example has been given in which the electric field (here, the electric field strength) in the space in which the vehicle 1 is located is made detectable using the electric field strength detection device 12 including the field effect transistor 15, the body metal part as the antenna 16, and the bias power supply 17, but of course, the present invention is not limited to this. For example, an electric field strength detection device 12 in which an element other than the body metal part is used as the antenna 16 may also be used. Alternatively, an electric field strength detection device 12 with a different configuration may also be used as long as it is capable of detecting the electric field strength in the space in which the vehicle 11 is located.

[0063] Furthermore, in the above embodiment, the case where electric field strength data on a sunny or cloudy day, humidity data, and vehicle type data are used as information regarding static electricity carried by the vehicle 11 while the vehicle 11 is traveling has been described, but of course this is merely one example. Data other than the above may also be added as information regarding static electricity. Alternatively, if it is determined that electric field strength data on a sunny or cloudy day alone is sufficient, the magnitude of static electricity carried by the vehicle 11 may be evaluated using only the electric field strength data. Alternatively, if the magnitude of static electricity carried by the vehicle 11 can be evaluated using a characteristic value other than the electric field strength, the characteristic value may be used instead of the electric field strength data. In short, any data may be used as long as it is information regarding static electricity carried by the vehicle 11 while the vehicle 11 is traveling.

[0064] Furthermore, in the above explanation, an example was given in which the electric field detection system according to the present invention is applied to a lightning strike prediction system, but the electric field detection system according to the present invention can also be applied to systems for predicting natural phenomena in which fluctuations in the state of an electric field are recognized as a sign of their occurrence. Of course, the electric field detection system according to the present invention can also be applied not only to prediction, but also to detecting the state of a natural phenomenon that is currently occurring from the state of the electric field. Alternatively, the electric field detection system according to the present invention can be applied to detecting or predicting various events that involve fluctuations in the state of an electric field, such as detecting accidents that involve fluctuations in the state of an electric field. [Explanation of symbols]

[0065] 10 Lightning strike prediction system 11 vehicles 11 Door Outer 12 Electric field strength detector 13 Vehicle location information acquisition device 14 Data Processing Device 15 Field-effect transistor 16 Antenna 17 Bias power supply 18 Measuring equipment 19 Electric field strength calculation section 20 Data communication equipment 21 Hygrometer 22 Data storage unit 23 Data Processing Unit 24 Weather Information Providers 25 facilities S1 Electrostatic information acquisition step S11 Weather judgment step S12: Running condition determination step S13 Electrostatic data acquisition step S2 First data acquisition step S3 Second data acquisition step S4 Lightning strike prediction step S41 Rainy weather judgment step S42 Correction step S43 Prediction process execution step

Claims

1. An electric field detection system for detecting an electric field strength in a space in which a vehicle is located, comprising: an electric field sensor provided in the vehicle and configured to detect information about an electric field in a space in which the vehicle is located; an electric field strength acquisition unit that acquires an electric field strength of a space in which the vehicle is located based on information about the electric field detected by the electric field sensor; An electric field detection system configured to correct the electric field strength based on information about static electricity carried by the vehicle while the vehicle is running.

2. The electric field detection system according to claim 1 , wherein the information about the static electricity carried by the vehicle includes at least the electric field strength acquired by the electric field strength acquisition unit on a sunny or cloudy day.

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