CN120403903A - Grain pile temperature detection method and system based on electromagnetic waves - Google Patents
Grain pile temperature detection method and system based on electromagnetic wavesInfo
- Publication number
- CN120403903A CN120403903A CN202510908131.8A CN202510908131A CN120403903A CN 120403903 A CN120403903 A CN 120403903A CN 202510908131 A CN202510908131 A CN 202510908131A CN 120403903 A CN120403903 A CN 120403903A
- Authority
- CN
- China
- Prior art keywords
- electromagnetic wave
- grain pile
- temperature
- electromagnetic
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/006—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using measurement of the effect of a material on microwaves or longer electromagnetic waves, e.g. measuring temperature via microwaves emitted by the object
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
The invention relates to the technical field of grain temperature detection, and discloses a grain pile temperature detection method and system based on electromagnetic waves, aiming at solving the problems of high cost and poor accuracy of the existing method; the method comprises the steps of installing a sensor matrix in a grain pile, obtaining the temperature of a point position detected by a temperature probe of each sensor, controlling each sensor to emit and receive electromagnetic wave signals, constructing an electromagnetic wave propagation equation set between any two sensors in the grain pile, generating an electromagnetic wave distribution field according to the frequency of the electromagnetic wave signals emitted by each sensor and the amplitude and the phase of the electromagnetic wave signals received by each sensor and based on the electromagnetic wave propagation equation set, and generating a temperature distribution field according to the electromagnetic wave distribution field. The invention reduces the cost and improves the accuracy, and is particularly suitable for granary.
Description
Technical Field
The invention relates to the technical field of grain temperature detection, in particular to a grain pile temperature detection method and system based on electromagnetic waves.
Background
The grain pile temperature detection is a process of monitoring the temperature inside and on the surface of the grain pile in real time or periodically in the grain storage process, and can prevent grain deterioration, control insect pest risk, optimize storage conditions and ensure grain storage safety and stability through grain pile temperature detection. However, the grain pile is used as a porous bulk medium, the temperature field distribution is influenced by environmental humidity, microorganism activity, bulk density and other multi-factor coupling, so that a significant temperature difference exists in the grain pile, the heat transfer of grains is uneven, and a single detection point is difficult to reflect the overall temperature distribution.
In the prior art, the main scheme of grain pile temperature detection is that a temperature sensor matrix is arranged in a grain pile, the temperatures of different positions of the grain pile are acquired through a plurality of temperature sensors of the temperature sensor matrix, and then a three-dimensional grain pile temperature distribution map is generated based on an interpolation algorithm. However, the method has the following problems that firstly, the precision of a temperature field is completely dependent on the number and distribution of temperature sensors, a large number of temperature sensors are needed to be embedded in a grain pile, the sealing performance of the grain pile is possibly damaged, a probe is easily damaged by machinery or fumigated and corroded, the maintenance cost is high, if the temperature sensors are arranged sparsely, the interpolation algorithm can cause a smooth effect due to insufficient data and can not capture local abnormality, meanwhile, the temperature sensors can cause sparse or gathering of points due to installation limitation, at the moment, the interpolation result is easy to have the problems of over-weighting of a central area and error amplification of an edge area, the reconstruction precision of the temperature field is reduced, secondly, the interpolation algorithm only depends on mathematical statistics rules, the physical characteristics of the grain pile are ignored, the dynamic change of an actual temperature field cannot be reflected, and thirdly, if local high temperature or low temperature abnormal points exist at a certain position of the grain pile, concentric circular temperature distribution is easily formed around the abnormal temperature points by the interpolation algorithm, the interpolation algorithm is inconsistent with the thermal conduction rule of the actual grain pile, and the precision is poor.
Disclosure of Invention
The invention aims to solve the problems of high cost and poor accuracy of the existing grain pile temperature detection method, and provides a grain pile temperature detection method and system based on electromagnetic waves.
The technical scheme adopted by the invention for solving the technical problems is as follows:
In a first aspect, the invention provides a grain pile temperature detection method based on electromagnetic waves, which comprises the following steps:
under an experimental environment, detecting electromagnetic parameters of the grain pile at different temperatures, and constructing a mapping relation between the temperatures and the electromagnetic parameters;
a sensor matrix is arranged in the grain pile, and each sensor in the sensor matrix comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module;
acquiring the temperature of the point position detected by the temperature probe of each sensor, controlling each sensor to emit and receive electromagnetic wave signals, and controlling the frequency of each sensor to emit the electromagnetic wave signals to correspond to the temperature of the point position;
Constructing an electromagnetic wave propagation equation between any two sensors in the grain pile, and generating an electromagnetic wave propagation equation set;
Generating an electromagnetic wave distribution field representing electromagnetic parameter distribution according to the frequency of each sensor transmitting an electromagnetic wave signal and the amplitude and phase of the received electromagnetic wave signal and based on the electromagnetic wave propagation equation set;
And generating a temperature distribution field for representing temperature distribution according to the electromagnetic wave distribution field and based on the mapping relation between the temperature and the electromagnetic parameters, and determining the temperature of any point in the grain pile according to the temperature distribution field.
Further, detecting electromagnetic parameters of the grain stack at different temperatures, comprising:
And measuring the amplitude and the phase of the electromagnetic wave before and after penetrating through the grain pile through the vector network analyzer at different temperatures, determining the attenuation coefficient and the phase delay of the electromagnetic wave according to the amplitude and the phase of the electromagnetic wave before and after penetrating through the grain pile, and calculating the electromagnetic parameters at corresponding temperatures according to the attenuation coefficient and the phase delay.
Further, the electromagnetic parameter is permittivity, permeability or conductivity.
Further, an electromagnetic wave propagation equation between any two sensors in the grain stack is constructed, including:
And determining a wave equation of the electric field intensity of the electromagnetic wave in the grain pile based on the Maxwell equation set, and constructing an electromagnetic wave propagation equation according to the wave equation of the electric field intensity of the electromagnetic wave in the grain pile.
Further, the maxwell equations are as follows:
;
;
;
;
the wave equation of the electric field strength in the grain pile is as follows:
;
Wherein, the The operator of the degree of divergence is represented,The rotation operator is represented by a rotation operator,The representation of the laplace operator is provided,The electric displacement vector is represented by a vector,The magnetic induction intensity is indicated by the magnetic induction,Indicating the strength of the electric field,The magnetic field strength is indicated as such,The current density is indicated as such,Indicating the magnetic permeability of the magnetic core,Indicating the dielectric constant of the material,The conductivity is indicated as being the value of the electrical conductivity,Representing the first derivative of the magnetic induction with respect to time,Representing the first derivative of the electrical displacement vector with respect to time,Representing the second derivative of the electric field strength with respect to time,Representing the first derivative of the electric field strength with respect to time.
Further, the electromagnetic wave propagation equation between any two sensors is as follows:
;
;
;
;
;
Wherein, the Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe phase delay at the time of the individual sensors,Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe propagation path of the individual sensors,An arc length parameter representing the propagation path, describing the position on the propagation path,Representing the positionA phase constant at which the phase of the light is constant,The integral variable is represented by a value of the integral variable,Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe amplitude at the time of the individual sensors decays,Representing a natural exponential function of the sign,Representing the positionThe attenuation coefficient at which the optical fiber is to be subjected to the optical fiber,Representing the positionThe real part of the dielectric constant at that point,Represents the angular frequency of the electromagnetic wave signal,The circumference ratio is indicated as such,Representing the frequency of the electromagnetic wave signal.
Further, generating an electromagnetic wave distribution field for representing the electromagnetic parameter distribution, comprising:
Discretizing the space of the grain pile into grain pile grids, calculating electromagnetic parameters corresponding to each grain pile grid according to the frequency of each sensor transmitting electromagnetic wave signals and the amplitude and phase of the received electromagnetic wave signals and based on the electromagnetic wave propagation equation set, and generating an electromagnetic wave distribution field for representing electromagnetic parameter distribution according to the electromagnetic parameters corresponding to each grain pile grid.
Further, generating a temperature distribution field for representing a temperature distribution, comprising:
And determining the temperature corresponding to each grain pile grid according to the electromagnetic parameters corresponding to each grain pile grid and based on the mapping relation between the temperature and the electromagnetic parameters, and generating a temperature distribution field for representing temperature distribution according to the temperature corresponding to each grain pile grid.
Further, each sensor in the sensor matrix is encapsulated with a wave transparent material.
In a second aspect, the present invention provides an electromagnetic wave based grain pile temperature detection system, the system comprising:
The experimental device is used for detecting electromagnetic parameters of the grain pile at different temperatures under an experimental environment and constructing a mapping relation between the temperature and the electromagnetic parameters;
The sensor matrix is arranged in the grain pile, and each sensor comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module;
The main control device is used for acquiring the temperature of the point position detected by the temperature probe of each sensor, controlling each sensor to transmit and receive electromagnetic wave signals, constructing an electromagnetic wave propagation equation set between any two sensors in the grain pile to generate an electromagnetic wave propagation equation set, generating an electromagnetic wave distribution field used for representing electromagnetic parameter distribution according to the frequency of the electromagnetic wave signals transmitted by each sensor and the amplitude and the phase of the electromagnetic wave signals received by each sensor and based on the electromagnetic wave propagation equation set, generating a temperature distribution field used for representing temperature distribution according to the electromagnetic wave distribution field and based on the mapping relation between the temperature and the electromagnetic parameters, and determining the temperature of any point in the grain pile according to the temperature distribution field.
The grain pile temperature detection method and system based on the electromagnetic waves have the beneficial effects that electromagnetic wave signal propagation characteristics and a temperature field are dynamically associated, electromagnetic parameters in the grain pile are inverted by utilizing phase delay and amplitude attenuation data among a plurality of sensor pairs based on the electromagnetic wave propagation characteristics and combining an electromagnetic wave propagation model constructed based on Maxwell equations, and then the electromagnetic parameters are converted into temperatures. The electromagnetic wave propagation path covers the whole grain pile, a single path can penetrate through a plurality of areas, and the temperature detection of millimeter-to-centimeter resolution can be realized even if the number of the sensors is limited by combining the cross data of a plurality of sensor pairs, so that the equipment cost and the maintenance cost of the sensors are reduced, the damage degree of the sensors to the sealing property of the grain pile is reduced, the temperature is determined by inverting electromagnetic parameters, the real physical process is more met, when the grain pile is suddenly changed due to uneven ventilation, the electromagnetic inversion can accurately reflect the abrupt change boundary, and the accuracy of the temperature detection is further improved.
Drawings
Fig. 1 is a flow chart of a grain pile temperature detection method based on electromagnetic waves according to an embodiment;
FIG. 2 is a schematic diagram of a sensor matrix mounting structure provided by an embodiment;
FIG. 3 is a schematic diagram illustrating transmission of electromagnetic wave signals according to an embodiment;
fig. 4 is a schematic structural diagram of an electromagnetic wave-based grain pile temperature detection system according to an embodiment.
Detailed Description
In order to make the person skilled in the art better understand the solution of the present invention, the technical solution in the present embodiment will be clearly and completely described below with reference to the drawings in the present embodiment.
In the description of the present invention and some of the flows described in the above figures, a plurality of operations occurring in a particular order are included, but it should be clearly understood that the operations may be performed out of order or performed in parallel, the sequence numbers of the operations are merely used to distinguish between the different operations, and the sequence numbers themselves do not represent any order of execution. In addition, the flows may include more or fewer operations, and the operations may be performed sequentially or in parallel.
The technical scheme of the invention is suitable for application scenes in which temperature detection needs to be carried out on grain piles, such as temperature detection of rice, wheat, corn and the like in a granary.
The conventional grain pile temperature detection scheme is to collect temperatures of a plurality of points of the grain pile by using a temperature sensor matrix, determine temperatures of other points by using an interpolation algorithm, and generate a temperature distribution field of the grain pile. According to the research on the existing grain pile temperature detection mode, the inventor discovers that the accuracy of a temperature distribution field in the prior art completely depends on the number and distribution of temperature sensors, a large number of temperature sensors need to be arranged, the equipment cost and the maintenance cost are high, the damage degree to the sealing property of the grain pile is large, and the accuracy is poor.
Based on the above, the invention provides a technical scheme, in the invention, under an experimental environment, electromagnetic parameters of a grain pile at different temperatures are detected, a mapping relation between the temperatures and the electromagnetic parameters is constructed, a sensor matrix is installed in the grain pile, each sensor in the sensor matrix respectively comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module, the temperature of a point position detected by the temperature probe of each sensor is obtained, each sensor is controlled to transmit and receive electromagnetic wave signals, the frequency of each sensor transmitting the electromagnetic wave signals corresponds to the temperature of the point position, an electromagnetic wave propagation equation set is constructed, an electromagnetic wave distribution field used for representing electromagnetic parameter distribution is generated according to the frequency of each sensor transmitting the electromagnetic wave signals and the amplitude and the phase of the electromagnetic wave signals and based on the electromagnetic wave propagation equation set, a temperature distribution field used for representing temperature distribution is generated according to the electromagnetic wave distribution field and based on the mapping relation between the temperatures and the electromagnetic parameters, and the temperature of any point position in the grain pile is determined according to the temperature distribution field.
It will be appreciated that the grain heap is made up of grain particles, and that temperature changes alter the molecular polarisation characteristics (e.g. water activity, ion mobility) of the grain particles, resulting in a change in electromagnetic parameters. Based on the method, firstly, the temperature of the grain pile and the electromagnetic parameters are dynamically related in an experimental environment, then the temperature of the point position is detected by using the sensors, electromagnetic wave signals are transmitted and received, finally, based on the propagation characteristics of electromagnetic waves, the electromagnetic wave propagation model is built by combining with phase delay and amplitude attenuation data among a plurality of sensor pairs and based on Maxwell equations, the electromagnetic parameters in the grain pile are inverted, and the electromagnetic parameters are converted into the temperature. The electromagnetic wave propagation path covers the whole grain pile, a single path can penetrate through a plurality of areas, and the temperature detection of millimeter-to-centimeter resolution can be realized even if the number of the sensors is limited by combining the cross data of a plurality of sensor pairs, so that the equipment cost and the maintenance cost of the sensors are reduced, the damage degree of the sensors to the sealing property of the grain pile is reduced, the temperature is determined by inverting electromagnetic parameters, the real physical process is more met, when the grain pile is suddenly changed due to uneven ventilation, the electromagnetic inversion can accurately reflect the abrupt change boundary, and the accuracy of the temperature detection is further improved.
The technical solutions of the present embodiment will be clearly and completely described below with reference to the drawings in the present embodiment, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments.
Fig. 1 shows a schematic flow chart of a grain pile temperature detection method based on electromagnetic waves, referring to fig. 1, the method comprises the following steps:
And 1, detecting electromagnetic parameters of the grain pile at different temperatures in an experimental environment, and constructing a mapping relation between the temperatures and the electromagnetic parameters.
It can be understood that the temperature dependence of the electromagnetic parameters of the grain pile is caused by the coupling effect of multiple physical fields, and the temperature change of the grain pile can lead to the change of moisture phase change, thermal expansion, biological metabolism and electromagnetic wave propagation characteristics, so that the electromagnetic parameters are changed, and based on the change, the embodiment constructs the mapping relation between the temperature and the electromagnetic parameters in the experimental environment.
In this embodiment, the electromagnetic parameter may be permittivity, permeability, or conductivity. Specifically, grain particles are heated and expanded to reduce the porosity and increase the stacking density, so that scattering interfaces in an electromagnetic wave propagation path are increased, the equivalent dielectric constant is increased, the respiration of microorganisms in a grain pile is activated at high temperature (20 ℃) to release CO 2 and moisture, meanwhile, the ion concentration is increased, the conductivity is remarkably improved, the magnetic permeability of trace metal impurities (such as scrap iron) in the grain pile can be slightly adjusted due to temperature change, for example, the ordered arrangement of the magnetic impurities can be reduced due to high temperature, and the magnetic permeability is reduced.
In this embodiment, electromagnetic parameters of the grain pile at different temperatures are detected, the amplitude and the phase of the electromagnetic wave before and after penetrating through the grain pile can be measured at different temperatures by the vector network analyzer, the attenuation coefficient and the phase delay of the electromagnetic wave are determined according to the amplitude and the phase of the electromagnetic wave before and after penetrating through the grain pile, and the electromagnetic parameters at the corresponding temperatures are calculated according to the attenuation coefficient and the phase delay.
In practical application, the grain pile can be compacted into a uniform cuboid or cylinder, under different temperatures, after the electromagnetic waves vertically penetrate through the grain pile, the attenuation coefficient and the phase delay of the electromagnetic waves can be calculated by measuring the transmission coefficient of the grain pile under specific frequency and combining the amplitude and the phase of the electromagnetic waves before and after penetration, and then the electromagnetic parameters of the grain pile are reversely deduced. The amplitude attenuation is directly related to the loss characteristic of the medium, the larger the loss is, the more obvious the electromagnetic wave amplitude attenuation is, while the phase change is related to the influence of the medium on the propagation speed of the electromagnetic wave, and the different electromagnetic parameters can change the propagation speed of the electromagnetic wave, so that the phase change is caused. The vector network analyzer is used to accurately measure the amplitude and phase difference of the incident wave and the penetrating wave, and then the complex dielectric constant, complex magnetic conductivity and other electromagnetic parameters of the medium can be accurately calculated through mathematical treatment. And meanwhile, the ambient temperature of the grain medium is tested, the temperature is corresponding to the electromagnetic parameter, and finally, the mapping relation between the temperature of the grain stack and the electromagnetic parameter is constructed.
And 2, installing a sensor matrix in the grain pile, wherein each sensor in the sensor matrix comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module.
Referring to fig. 2, in practical application, a plurality of sensors may be distributed in the grain pile, and the distance between adjacent sensors may be dynamically adjusted according to the grain pile size and the monitoring resolution requirement. Each sensor is integrated with a temperature probe (such as a thermocouple or a thermistor), an electromagnetic wave transmitting module and an electromagnetic wave receiving module, wherein the temperature probe is used for detecting the temperature of the point where the temperature probe is located, the electromagnetic wave transmitting module is used for transmitting electromagnetic wave signals, and the electromagnetic wave receiving module is used for receiving the electromagnetic wave signals. Each sensor is respectively in communication connection with a main control device, and the main control device is used for receiving the temperature detected by the sensor, controlling the sensor to emit electromagnetic wave signals and receiving relevant data of the electromagnetic wave signals sent by the sensor.
In this embodiment, each sensor in the sensor matrix adopts a passive sensor, no battery is needed for power supply, and the sensor adopts a wave-transparent material (such as polypropylene) for encapsulation, so as to reduce interference on electromagnetic wave signals and further improve accuracy of temperature detection.
And 3, acquiring the temperature of the point position detected by the temperature probe of each sensor, and controlling each sensor to transmit and receive electromagnetic wave signals, wherein the frequency of each sensor transmitting the electromagnetic wave signals corresponds to the temperature of the point position.
The temperature probe of each sensor detects the temperature of the point in real time, and the temperature data is transmitted to the main control device through analog-to-digital conversion or a direct digital interface. Referring to fig. 3, for any two sensors, the main control device generates an excitation signal corresponding to the electromagnetic frequency according to the temperature value, so as to control the electromagnetic wave transmitting modules of the sensors to transmit electromagnetic wave signals corresponding to the frequency, and the electromagnetic wave receiving module of each sensor receives the electromagnetic wave signals transmitted by other sensors and returns the relevant data of the received electromagnetic wave signals to the main control device.
And 4, constructing an electromagnetic wave propagation equation between any two sensors in the grain pile, and generating an electromagnetic wave propagation equation set.
In the embodiment, an electromagnetic wave propagation equation between any two sensors in the grain pile is constructed, and the electromagnetic wave propagation equation specifically comprises:
And determining a wave equation of the electric field intensity of the electromagnetic wave in the grain pile based on the Maxwell equation set, and constructing an electromagnetic wave propagation equation according to the wave equation of the electric field intensity of the electromagnetic wave in the grain pile.
Maxwell's Equations are a set of partial differential Equations describing the relationship between electric and magnetic fields and charge density, current density, and consist of four Equations, respectively gaussian law describing how electric charges produce electric fields, gao Sici's law indicating the absence of magnetic monopoles, faraday's law of induction explaining how time-varying magnetic fields produce electric fields, and Maxwell-ampere's law describing how electric currents and time-varying electric fields produce magnetic fields.
In this example, in a passive, linear, isotropic grain pile medium, the differential form of maxwell's equations is as follows:
;
;
;
;
The wave equation of the electric field intensity of the electromagnetic wave in the grain pile can be deduced from maxwell equation set, as follows:
;
Wherein, the The operator of the degree of divergence is represented,The rotation operator is represented by a rotation operator,The representation of the laplace operator is provided,The electric displacement vector is represented by a vector,The magnetic induction intensity is indicated by the magnetic induction,Indicating the strength of the electric field,The magnetic field strength is indicated as such,The current density is indicated as such,Indicating the magnetic permeability of the magnetic core,Indicating the dielectric constant of the material,The conductivity is indicated as being the value of the electrical conductivity,Representing the first derivative of the magnetic induction with respect to time,Representing the first derivative of the electrical displacement vector with respect to time,Representing the second derivative of the electric field strength with respect to time,Representing the first derivative of the electric field strength with respect to time.
When the electromagnetic wave propagates in the grain pile medium, the phase and amplitude changes are related to the path integral, and based on the phase and amplitude changes, the wave equation of the electromagnetic wave in the grain pile can be used for any two sensors according to the electric field strength of the electromagnetic waveEstablishing an electromagnetic wave propagation equation to describe the electromagnetic wave from the firstThe first sensor propagates toElectromagnetic wave propagation characteristics (phase delay and amplitude attenuation) of the individual sensors are as follows:
;
;
;
;
;
Wherein, the Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe phase delay at the time of the individual sensors,Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe propagation path of the individual sensors,An arc length parameter representing the propagation path, describing the position on the propagation path,Representing the positionA phase constant at which a phase change per unit length of the electromagnetic wave propagates in the medium is characterized,The integral variable is represented by a value of the integral variable,Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe amplitude at the time of the individual sensors decays,Representing a natural exponential function of the sign,Representing the positionAn attenuation coefficient at the position, which represents the energy attenuation of unit length when the electromagnetic wave propagates in the medium,Representing the positionThe real part of the dielectric constant at that point,Represents the angular frequency of the electromagnetic wave signal,The circumference ratio is indicated as such,Representing the frequency of the electromagnetic wave signal.
In the electromagnetic wave propagation equation, the phase delay and the amplitude attenuation of electromagnetic wave propagation are related to the medium characteristics of each point on the path, and the propagation characteristics of electromagnetic waves in non-uniform medium can be accurately described by integrating the path, so that the accuracy of temperature detection is further improved. Furthermore, the attenuation of electromagnetic waves is determined by the absorption characteristics of the medium, whereas the absorption process is generally exponential, so that the linear integral can be mapped to the actual attenuation amplitude by an exponential function. The propagation behavior of the electromagnetic wave in the complex medium can be accurately modeled through integral and exponential functions, and a mathematical basis is provided for the subsequent inversion temperature.
And 5, generating an electromagnetic wave distribution field for representing electromagnetic parameter distribution according to the frequency of each sensor transmitting the electromagnetic wave signal and the amplitude and phase of the received electromagnetic wave signal and based on the electromagnetic wave propagation equation set.
In the present embodiment, generating an electromagnetic wave distribution field for representing an electromagnetic parameter distribution includes:
Discretizing the space of the grain pile into grain pile grids, calculating electromagnetic parameters corresponding to each grain pile grid according to the frequency of each sensor transmitting electromagnetic wave signals and the amplitude and phase of the received electromagnetic wave signals and based on the electromagnetic wave propagation equation set, and generating an electromagnetic wave distribution field for representing electromagnetic parameter distribution according to the electromagnetic parameters corresponding to each grain pile grid.
In practical application, firstly, the grain pile space is divided intoWherein, the grain pile grid comprises a grid body,Indicating the length of the grain pile grid,Representing the width of the grain pile grid,The method comprises the steps of representing the height of a grain pile grid, setting the specific size of the grain pile grid according to the detection resolution requirement (such as 1cm & lt 3 & gt), determining the position information of each grain pile grid relative to a sensor to determine the position of electromagnetic waves on a propagation path, performing path integral dispersion on each grain pile grid on the electromagnetic propagation path for any two sensors, determining the phase delay and the amplitude attenuation of the electromagnetic wave signals on the propagation path according to the amplitude and the phase of received electromagnetic wave signals, substituting the frequency of the electromagnetic wave signals transmitted by each sensor and the phase delay and the amplitude attenuation of the electromagnetic wave signals on the propagation path into corresponding equations in an electromagnetic wave propagation equation set, inverting to obtain electromagnetic parameters of each grain pile grid, and finally mapping the electromagnetic parameters of each grain pile grid obtained by inversion to three-dimensional space coordinates of grain piles to obtain an electromagnetic wave distribution field representing the distribution of the electromagnetic parameters of the grain piles.
The grain pile is discretized into grids, an electromagnetic wave propagation equation set is constructed, and inversion solution is carried out, so that the finally generated electromagnetic parameter distribution field can reflect electromagnetic parameter distribution in the grain pile with high resolution.
And 6, generating a temperature distribution field for representing temperature distribution according to the electromagnetic wave distribution field and based on the mapping relation between the temperature and the electromagnetic parameters, and determining the temperature of any point in the grain pile according to the temperature distribution field.
Specifically, according to the electromagnetic parameters of each grain pile grid and based on the mapping relation between the temperature constructed in the step 1 and the electromagnetic parameters, the temperature of each grain pile grid can be obtained, and the temperature of each grain pile grid is mapped to the three-dimensional space coordinates of the grain pile, so that an electromagnetic wave distribution field representing the distribution of the electromagnetic parameters of the grain pile can be obtained. When the temperature of the grain pile at a certain point is required to be determined, the temperature of the grain pile grid at which the point is located is directly taken, and the temperature of any point in the grain pile is determined.
In summary, according to the grain pile temperature detection method based on electromagnetic waves provided by the embodiment, electromagnetic parameters in the grain pile are inverted by combining an electromagnetic wave propagation model constructed based on maxwell's equations and utilizing phase delay and amplitude attenuation data among a plurality of sensor pairs based on the electromagnetic wave propagation characteristics by dynamically correlating the electromagnetic wave signal propagation characteristics with a temperature field, so that the electromagnetic parameters are converted into temperatures. The electromagnetic wave propagation path covers the whole grain pile, a single path can penetrate through a plurality of areas, and the temperature detection of millimeter-to-centimeter resolution can be realized even if the number of the sensors is limited by combining the cross data of a plurality of sensor pairs, so that the equipment cost and the maintenance cost of the sensors are reduced, the damage degree of the sensors to the sealing property of the grain pile is reduced, the temperature is determined by inverting electromagnetic parameters, the real physical process is more met, when the grain pile is suddenly changed due to uneven ventilation, the electromagnetic inversion can accurately reflect the abrupt change boundary, and the accuracy of the temperature detection is further improved.
Based on the above-mentioned scheme, this embodiment also provides a grain pile temperature detection system based on electromagnetic waves, please refer to fig. 4, the system includes:
The experimental device is used for detecting electromagnetic parameters of the grain pile at different temperatures under an experimental environment and constructing a mapping relation between the temperature and the electromagnetic parameters;
The sensor matrix is arranged in the grain pile, and each sensor comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module;
The main control device is used for acquiring the temperature of the point position detected by the temperature probe of each sensor, controlling each sensor to transmit and receive electromagnetic wave signals, constructing an electromagnetic wave propagation equation set between any two sensors in the grain pile to generate an electromagnetic wave propagation equation set, generating an electromagnetic wave distribution field used for representing electromagnetic parameter distribution according to the frequency of the electromagnetic wave signals transmitted by each sensor and the amplitude and the phase of the electromagnetic wave signals received by each sensor and based on the electromagnetic wave propagation equation set, generating a temperature distribution field used for representing temperature distribution according to the electromagnetic wave distribution field and based on the mapping relation between the temperature and the electromagnetic parameters, and determining the temperature of any point in the grain pile according to the temperature distribution field.
It can be understood that, since the electromagnetic wave-based grain pile temperature detection system described in this embodiment is a system for implementing the electromagnetic wave-based grain pile temperature detection method described in the embodiment, for the system disclosed in the embodiment, since the system corresponds to the method disclosed in the embodiment, the description is simpler, and the relevant places only need to refer to part of the description of the method, and are not repeated herein.
Claims (10)
1. The grain pile temperature detection method based on electromagnetic waves is characterized by comprising the following steps:
under an experimental environment, detecting electromagnetic parameters of the grain pile at different temperatures, and constructing a mapping relation between the temperatures and the electromagnetic parameters;
a sensor matrix is arranged in the grain pile, and each sensor in the sensor matrix comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module;
acquiring the temperature of the point position detected by the temperature probe of each sensor, controlling each sensor to emit and receive electromagnetic wave signals, and controlling the frequency of each sensor to emit the electromagnetic wave signals to correspond to the temperature of the point position;
Constructing an electromagnetic wave propagation equation between any two sensors in the grain pile, and generating an electromagnetic wave propagation equation set;
Generating an electromagnetic wave distribution field representing electromagnetic parameter distribution according to the frequency of each sensor transmitting an electromagnetic wave signal and the amplitude and phase of the received electromagnetic wave signal and based on the electromagnetic wave propagation equation set;
And generating a temperature distribution field for representing temperature distribution according to the electromagnetic wave distribution field and based on the mapping relation between the temperature and the electromagnetic parameters, and determining the temperature of any point in the grain pile according to the temperature distribution field.
2. The electromagnetic wave based grain pile temperature detection method according to claim 1, wherein detecting electromagnetic parameters of the grain pile at different temperatures comprises:
And measuring the amplitude and the phase of the electromagnetic wave before and after penetrating through the grain pile through the vector network analyzer at different temperatures, determining the attenuation coefficient and the phase delay of the electromagnetic wave according to the amplitude and the phase of the electromagnetic wave before and after penetrating through the grain pile, and calculating the electromagnetic parameters at corresponding temperatures according to the attenuation coefficient and the phase delay.
3. The electromagnetic wave based grain pile temperature detection method according to claim 1, wherein the electromagnetic parameter is permittivity, permeability or conductivity.
4. The electromagnetic wave based grain pile temperature detection method according to claim 3, wherein constructing an electromagnetic wave propagation equation between any two sensors in the grain pile comprises:
And determining a wave equation of the electric field intensity of the electromagnetic wave in the grain pile based on the Maxwell equation set, and constructing an electromagnetic wave propagation equation according to the wave equation of the electric field intensity of the electromagnetic wave in the grain pile.
5. The electromagnetic wave based grain pile temperature detection method according to claim 4, wherein the maxwell's equations are as follows:
;
;
;
;
the wave equation of the electric field strength in the grain pile is as follows:
;
Wherein, the The operator of the degree of divergence is represented,The rotation operator is represented by a rotation operator,The representation of the laplace operator is provided,The electric displacement vector is represented by a vector,The magnetic induction intensity is indicated by the magnetic induction,Indicating the strength of the electric field,The magnetic field strength is indicated as such,The current density is indicated as such,Indicating the magnetic permeability of the magnetic core,Indicating the dielectric constant of the material,The conductivity is indicated as being the value of the electrical conductivity,Representing the first derivative of the magnetic induction with respect to time,Representing the first derivative of the electrical displacement vector with respect to time,Representing the second derivative of the electric field strength with respect to time,Representing the first derivative of the electric field strength with respect to time.
6. The electromagnetic wave based grain pile temperature detection method according to claim 5, wherein an electromagnetic wave propagation equation between any two sensors is as follows:
;
;
;
;
;
Wherein, the Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe phase delay at the time of the individual sensors,Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe propagation path of the individual sensors,An arc length parameter representing the propagation path, describing the position on the propagation path,Representing the positionA phase constant at which the phase of the light is constant,The integral variable is represented by a value of the integral variable,Represent the firstElectromagnetic waves of the individual sensors propagate to the firstThe amplitude at the time of the individual sensors decays,Representing a natural exponential function of the sign,Representing the positionThe attenuation coefficient at which the optical fiber is to be subjected to the optical fiber,Representing the positionThe real part of the dielectric constant at that point,Represents the angular frequency of the electromagnetic wave signal,The circumference ratio is indicated as such,Representing the frequency of the electromagnetic wave signal.
7. The electromagnetic wave based grain pile temperature detection method of claim 6, wherein generating an electromagnetic wave distribution field representing an electromagnetic parameter distribution comprises:
Discretizing the space of the grain pile into grain pile grids, calculating electromagnetic parameters corresponding to each grain pile grid according to the frequency of each sensor transmitting electromagnetic wave signals and the amplitude and phase of the received electromagnetic wave signals and based on the electromagnetic wave propagation equation set, and generating an electromagnetic wave distribution field for representing electromagnetic parameter distribution according to the electromagnetic parameters corresponding to each grain pile grid.
8. The electromagnetic wave based grain pile temperature detection method according to claim 7, wherein generating a temperature distribution field for representing a temperature distribution comprises:
And determining the temperature corresponding to each grain pile grid according to the electromagnetic parameters corresponding to each grain pile grid and based on the mapping relation between the temperature and the electromagnetic parameters, and generating a temperature distribution field for representing temperature distribution according to the temperature corresponding to each grain pile grid.
9. The electromagnetic wave based grain pile temperature detection method of claim 1, wherein each sensor in the sensor matrix is encapsulated with a wave transparent material.
10. An electromagnetic wave based grain pile temperature detection system, characterized in that the system comprises:
The experimental device is used for detecting electromagnetic parameters of the grain pile at different temperatures under an experimental environment and constructing a mapping relation between the temperature and the electromagnetic parameters;
The sensor matrix is arranged in the grain pile, and each sensor comprises a temperature probe, an electromagnetic wave transmitting module and an electromagnetic wave receiving module;
The main control device is used for acquiring the temperature of the point position detected by the temperature probe of each sensor, controlling each sensor to transmit and receive electromagnetic wave signals, constructing an electromagnetic wave propagation equation set between any two sensors in the grain pile to generate an electromagnetic wave propagation equation set, generating an electromagnetic wave distribution field used for representing electromagnetic parameter distribution according to the frequency of the electromagnetic wave signals transmitted by each sensor and the amplitude and the phase of the electromagnetic wave signals received by each sensor and based on the electromagnetic wave propagation equation set, generating a temperature distribution field used for representing temperature distribution according to the electromagnetic wave distribution field and based on the mapping relation between the temperature and the electromagnetic parameters, and determining the temperature of any point in the grain pile according to the temperature distribution field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202510908131.8A CN120403903B (en) | 2025-07-02 | 2025-07-02 | Grain pile temperature detection method and system based on electromagnetic waves |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202510908131.8A CN120403903B (en) | 2025-07-02 | 2025-07-02 | Grain pile temperature detection method and system based on electromagnetic waves |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN120403903A true CN120403903A (en) | 2025-08-01 |
| CN120403903B CN120403903B (en) | 2025-09-16 |
Family
ID=96510673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202510908131.8A Active CN120403903B (en) | 2025-07-02 | 2025-07-02 | Grain pile temperature detection method and system based on electromagnetic waves |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN120403903B (en) |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09142620A (en) * | 1995-11-21 | 1997-06-03 | Mitsubishi Heavy Ind Ltd | Temperature detector for refrigerator |
| US20100079282A1 (en) * | 2007-06-15 | 2010-04-01 | Icove David J | Passive microwave speed and intrusion detection system |
| CN101957404A (en) * | 2009-07-20 | 2011-01-26 | 中国科学院遥感应用研究所 | Microwave measurement method of dielectric constant of grain pile |
| CN102175924A (en) * | 2011-03-14 | 2011-09-07 | 中国科学院遥感应用研究所 | Method and device for measuring dielectric constant of grain stack |
| CN102243161A (en) * | 2011-04-15 | 2011-11-16 | 中国科学院遥感应用研究所 | Multi-frequency electromagnetic measurement method for density and moisture content of grain |
| CN102288324A (en) * | 2011-07-26 | 2011-12-21 | 沈阳工业大学 | Acoustic monitoring method for temperature distribution of stored grain |
| US20160216157A1 (en) * | 2012-12-21 | 2016-07-28 | Centre National De La Recherche Scientifique - Cnrs - | Optical measurement of a temperature of an object, and associated mapping |
| CN106154051A (en) * | 2016-06-16 | 2016-11-23 | 电子科技大学 | Free space terminal short circuit material high temperature complex dielectric constant thermal stratification matching algorithm |
| CN115046653A (en) * | 2022-04-28 | 2022-09-13 | 河南科技大学 | Cross-regional stored grain temperature variation detection method based on temperature field cloud picture |
| CN218121811U (en) * | 2022-04-22 | 2022-12-23 | 山东豌豆检测服务有限公司 | A basic characteristic detection device for granular food |
| WO2024073852A1 (en) * | 2022-10-05 | 2024-04-11 | Bitstrata Systems Inc. | Radar-based yield monitoring and grain quality measurement system |
| CN222529273U (en) * | 2023-10-27 | 2025-02-25 | 深圳市万物唯识信息科技有限公司 | A multifunctional composite sensor device for food safety detection |
| CN120405241A (en) * | 2025-07-02 | 2025-08-01 | 中储粮成都储藏研究院有限公司 | A device and method for measuring electromagnetic parameters of grain |
-
2025
- 2025-07-02 CN CN202510908131.8A patent/CN120403903B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09142620A (en) * | 1995-11-21 | 1997-06-03 | Mitsubishi Heavy Ind Ltd | Temperature detector for refrigerator |
| US20100079282A1 (en) * | 2007-06-15 | 2010-04-01 | Icove David J | Passive microwave speed and intrusion detection system |
| CN101957404A (en) * | 2009-07-20 | 2011-01-26 | 中国科学院遥感应用研究所 | Microwave measurement method of dielectric constant of grain pile |
| CN102175924A (en) * | 2011-03-14 | 2011-09-07 | 中国科学院遥感应用研究所 | Method and device for measuring dielectric constant of grain stack |
| CN102243161A (en) * | 2011-04-15 | 2011-11-16 | 中国科学院遥感应用研究所 | Multi-frequency electromagnetic measurement method for density and moisture content of grain |
| CN102288324A (en) * | 2011-07-26 | 2011-12-21 | 沈阳工业大学 | Acoustic monitoring method for temperature distribution of stored grain |
| US20160216157A1 (en) * | 2012-12-21 | 2016-07-28 | Centre National De La Recherche Scientifique - Cnrs - | Optical measurement of a temperature of an object, and associated mapping |
| CN106154051A (en) * | 2016-06-16 | 2016-11-23 | 电子科技大学 | Free space terminal short circuit material high temperature complex dielectric constant thermal stratification matching algorithm |
| CN218121811U (en) * | 2022-04-22 | 2022-12-23 | 山东豌豆检测服务有限公司 | A basic characteristic detection device for granular food |
| CN115046653A (en) * | 2022-04-28 | 2022-09-13 | 河南科技大学 | Cross-regional stored grain temperature variation detection method based on temperature field cloud picture |
| WO2024073852A1 (en) * | 2022-10-05 | 2024-04-11 | Bitstrata Systems Inc. | Radar-based yield monitoring and grain quality measurement system |
| CN222529273U (en) * | 2023-10-27 | 2025-02-25 | 深圳市万物唯识信息科技有限公司 | A multifunctional composite sensor device for food safety detection |
| CN120405241A (en) * | 2025-07-02 | 2025-08-01 | 中储粮成都储藏研究院有限公司 | A device and method for measuring electromagnetic parameters of grain |
Non-Patent Citations (1)
| Title |
|---|
| 廉飞宇: "大型平房仓储粮水分分布的电磁波检测理论与方法研究", CNKI博士学位论文全文库信息科技辑, vol. 2013, no. 2, 15 February 2013 (2013-02-15), pages 2 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN120403903B (en) | 2025-09-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103792340B (en) | A saline soil monitoring and early warning system and method based on the Internet of Things | |
| CN113406007A (en) | Soil moisture content intelligent monitoring system based on heat pulse identical weak fiber grating array and in-situ calibration method | |
| CN107238826B (en) | Method for inverting thunderstorm charge distribution by using dual-polarization Doppler weather radar echo | |
| Wu et al. | Analysis of low-frequency drone-borne GPR for root-zone soil electrical conductivity characterization | |
| CN102288324A (en) | Acoustic monitoring method for temperature distribution of stored grain | |
| CN120217726B (en) | Battery multi-physical field reconstruction method and system based on physical information radial basis function | |
| CN113819851B (en) | Strain monitoring system of airborne radome based on distributed fiber bragg grating | |
| Cominelli et al. | Calibration of TEROS 10 and TEROS 12 electromagnetic soil moisture sensors | |
| CN120405241B (en) | Grain electromagnetic parameter measuring device and method | |
| CN109813500B (en) | A method for locating the leakage position of HDPE membrane by using the principle of finite difference time domain | |
| CN120403903B (en) | Grain pile temperature detection method and system based on electromagnetic waves | |
| CN110766561A (en) | Abnormal grain condition detection method based on wireless tomography technology | |
| Baumbauer et al. | The effect of soil water content and crop canopy on passive UHF-RFID wireless links | |
| Li et al. | Study on actively heated fiber Bragg grating sensing technology for expansive soil moisture considering the influence of cracks | |
| CN120427140B (en) | Grain pile temperature calibration method and system based on thermodynamics | |
| CN115902875B (en) | Ground penetrating radar forward simulation method and system based on LOD-FDTD | |
| Parashar et al. | Designing efficient soil resistivity measurement technique for agricultural wireless sensor network | |
| CN116165446A (en) | Electromagnetic wave signal management system and method for anechoic chamber | |
| CN209560703U (en) | The detection device and detection system of heat fire detector | |
| CN114280521B (en) | Calibration method and device of electromagnetic field probe, electronic equipment and storage medium | |
| CN115753997A (en) | Soil moisture detection method, system and storage medium | |
| CN120708391B (en) | Environment data wireless monitoring method and system for intelligent agriculture | |
| CN223597581U (en) | A dielectric matrix moisture sensor | |
| CN120779064B (en) | Uncertainty assessment method and device for three-dimensional positive-determination ultrasonic anemometer | |
| Ye et al. | Soil temperature detection based on acoustic method and improved Wyllie model |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |