An online microwave moisture detection device and method

Abstract

The present invention discloses an online microwave moisture detection device and method, comprising: a movable gantry, the movable gantry comprising two legs arranged at a set distance, the legs being able to move horizontally in set directions respectively; microwave antenna groups for transmitting and receiving each other are respectively arranged on opposite sides of the legs, the microwave antenna groups being able to rise and fall vertically along the legs; a main controller being configured to plan a scanning trajectory according to the range of the material to be detected, so as to control the horizontal movement and vertical rise and fall of the microwave antenna group; and at the same time controlling the microwave antenna group at each scanning point, each antenna transmits once in turn, and the remaining antennas receive at the same time. The present invention adopts bidirectional cross-microwave transmission and reflection of multiple antennas in the left and right antenna groups, and forms a microwave path of transmission and reflection through single transmission and multiple reception, so as to realize spatially distributed microwave detection.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic on-line microwave moisture detection for a whole vehicle, and in particular to an on-line microwave moisture detection device and method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Online moisture detection of whole vehicle materials is an urgent need for moisture content detection in feed, grain drying, sintering materials, sludge, tobacco, tobacco leaves, crude oil, coal, sand and gravel, food, chemical and other industries. The economic interests involved are huge. How to objectively and accurately measure the moisture content and deduct water for conversion is the most controversial link between the two parties in corporate procurement and material recycling trade.

[0004] With the advancement of technology, manual identification, near-infrared moisture meters, sampling drying and weighing methods, and other moisture measurement methods that are power-consuming, time-consuming, one-sided, low-precision, and require manual intervention have gradually been eliminated, and microwave moisture detection equipment has gradually developed.

[0005] Microwave is an electromagnetic wave with a frequency between 300MHZ-300GHZ and a wavelength between 1mm-1m. When microwaves pass through materials containing water molecules, the water molecules with higher polarity absorb microwave energy and are more sensitive to microwaves than the materials. The moisture content in the material can be determined by measuring the absorbed energy and the effect of moisture on the microwave phase.

[0006] The basic principle of the method of using microwave transmission and reflection to measure the moisture content in materials is to compare the energy and phase of the emitted microwaves with the received microwaves. As electromagnetic waves, microwaves have multiple propagation pathways such as transmission, scattering, reflection, and diffraction, presenting an extremely complex spatial distribution, which is the difficulty and key point restricting the practice of microwave water measurement.

[0007] Existing technologies often use the method of bringing the antenna as close as possible to the material to be tested to limit the distribution space of microwaves. For example, the existing microwave water measurement of cigarette packages and grain conveyor belts require the size or packaging specifications of the material so that the transceiver antenna is close to the material. If the material is unloaded, unpacked, and scattered and sent to the conveyor belt for testing, a large amount of manpower, space, and equipment will be added, and the operation efficiency will be low; the existing vehicle online microwave moisture detection equipment on the market can be classified as an enlarged version of the cigarette package detector, and none of them solves the complexity of the spatial distribution of microwaves when the antenna is away from the material, and cannot adapt to a variety of vehicle models, loading forms, and packaging specifications. Summary of the invention

[0008] In order to solve the above problems, the present invention proposes an online microwave moisture detection device and method, which adopts left and right antenna groups and multiple antennas for bidirectional cross microwave transmission and reflection to form spatially distributed microwave detection, so as to realize microwave scanning of the entire range of materials according to the path.

[0009] According to a first aspect of the present invention, an online microwave moisture detection device is disclosed, comprising:

[0010] A movable gantry, the movable gantry comprising two legs arranged at a set distance, the legs being able to move horizontally in set directions respectively; microwave antenna groups for transmitting and receiving to each other are respectively arranged on opposite sides of the legs, the microwave antenna groups being able to rise and fall vertically along the legs;

[0011] The main controller is configured to plan the scanning trajectory according to the range of the material to be detected to control the horizontal movement and vertical lifting of the microwave antenna group; at the same time, the microwave antenna group is controlled to transmit once at each scanning point, and the remaining antennas receive at the same time.

[0012] As a further solution, the tops of the two legs are connected by a crossbeam; the two legs and the crossbeam are respectively provided with a distance sensor and a temperature and humidity sensor.

[0013] As a further solution, each antenna transmits once in sequence, and the remaining antennas receive simultaneously, so that direct transmission reception, cross transmission reception and reflection reception can be formed at each scanning point.

[0014] As a further solution, the two legs can move along the horizontal guide rail in a set direction; vertical lifting mechanisms are respectively provided on opposite sides of the legs, and microwave antenna groups for transmitting and receiving to each other are respectively provided on the vertical lifting mechanisms.

[0015] As a further solution, it also includes: a PLC controller, which communicates with the main controller; the PLC controller is used to control the horizontal movement of the two legs and the vertical lifting of the vertical lifting mechanism.

[0016] As a further solution, the microwave antenna group includes three pairs of narrow-band microwave antennas for transmitting and receiving to each other.

[0017] As a further solution, the distance between the two legs can ensure the passage of material carrying vehicles.

[0018] According to a second aspect of the present invention, an online microwave moisture detection method is disclosed, comprising:

[0019] Plan the scanning trajectory according to the chassis direction of the transport vehicle and the material loading height;

[0020] Control the moving path of the microwave antenna group according to the scanning trajectory to ensure full scanning of the material range;

[0021] At each scanning point, each antenna in the microwave antenna group is controlled to transmit once in turn, and the remaining antennas receive at the same time, so that the same area of ​​the material is irradiated with microwaves in different directions and forms transmission and reflection reception;

[0022] Measure the value and phase of microwave emission and reception, and calculate the moisture content of each section.

[0023] As a further solution, the microwave emission and reception values ​​and phases are measured to calculate the water content of each section. The specific process includes:

[0024] The transceiver antenna arrays are arranged on both sides of the vehicle or the object being tested, with one end transmitting microwaves and the other end receiving them. The equipment automatically measures and records the energy value and phase difference of microwave transmission and reception, and simultaneously measures the temperature and humidity through temperature and humidity sensors, and uses distance sensors to measure the three-dimensional shape indicators of the goods being tested. Based on the microwave medium propagation attenuation and polarization reaction principles, the moisture content of the goods in the vehicle being tested is calculated.

[0025] As a further solution, the interface formed by each experience point in the scanning direction is refined into multiple areas, and different colors representing moisture content are used to distinguish them, forming a thermal map of moisture content distributed in the material space.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention can truly realize the online automatic detection of the moisture content of the whole vehicle materials (paper packages, wood chips, tobacco, grain and other non-metallic materials), is adaptable to various vehicle models and material packaging forms, does not need to unload materials, and the detection process is fully automatic.

[0028] The present invention adopts the left and right antenna groups and multiple antennas for two-way cross microwave transmission and reflection, and forms a transmission and reflection microwave path through single-transmission and multiple-reception, so as to realize spatially distributed microwave detection;

[0029] The present invention achieves the goal of horizontal movement and vertical lifting of microwave antennas so that the scanning trajectory and the beam width of each antenna are coordinated to ensure that the material range is scanned just right, avoiding interference from invalid scanning areas; one antenna transmits and multiple antennas receive, ensuring that both transmission and reflection are taken into account, so that the same area of ​​the material is irradiated by microwaves in different directions and forms transmission and reflection, thus comprehensively and accurately describing the spatial influence of the moisture content of each area of ​​the material on the microwave.

[0030] The present invention realizes accurate and comprehensive online automatic microwave moisture detection of the whole vehicle through the reception and transmission value and phase of the microwave antenna, combined with the physical size and relative position obtained by ranging, taking into account the compensation of temperature and humidity, the basic data of space detection when there is no material, and the support of data such as detection calibration of standard samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 2 is a schematic structural diagram of an online microwave moisture detection device according to an embodiment of the present invention;

[0032] Figure 2 This is a principle block diagram of an online microwave moisture detection device in an embodiment of the present invention;

[0033] 3(a)-(f) are schematic diagrams of microwave antenna group transmission and reception in embodiments of the present invention;

[0034] 4(a)-(c) are schematic vertical cross-sectional views of scanning tracks according to an embodiment of the present invention;

[0035] Among them, 1. vertical lifting mechanism, 2. left antenna group, 3. left transceiver, 4. right antenna group, 5. right transceiver, 6. ultrasonic ranging sensor, 7. acquisition controller, 8. PLC controller, 9. movable gantry, 10. horizontal track, 11. temperature and humidity sensor, 12. main controller. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Embodiment 1

[0039] In one or more embodiments, an online microwave moisture detection device is disclosed, which scans the width and height range of the material by moving the antenna, integrates the distance between the antenna and the material, and the relationship between the antenna and the edge of the material, and incorporates many factors affecting microwave moisture detection, such as ambient temperature and humidity, and surrounding electrical measurement environment, into a comprehensive solution, thereby truly realizing online automatic and accurate moisture detection of the entire vehicle material and accurately detecting the moisture distribution in the material.

[0040] The difficulty and key point of microwave water measurement practice is the multi-path propagation of microwaves and the extremely complex spatial distribution. The method of this embodiment has two key points:

[0041] One is the relationship between the microwave scanning range and the material range. To ensure the corresponding effectiveness of the emitted microwaves and the received microwaves, the microwave scanning range should just cover the material being measured. If the scanning range is large, there will be direct waves, and the surrounding interference will increase, causing the measurement error to increase sharply. If the scanning range is small, the measurement will not be comprehensive.

[0042] Second, the material is three-dimensional, and the distribution of moisture content in each part is different. The distance the microwave reaches the moisture-containing area and the incident direction of the microwave relative to the moisture-containing area will both show different transmission and reflection.

[0043] Reference Figure 1 and Figure 2 The structure of the online microwave moisture detection device specifically includes:

[0044] The movable gantry 9 comprises two legs arranged at a set distance, the two legs are arranged in parallel, and the distance between the two legs can ensure that a material carrying vehicle can pass between the two legs; the tops of the two legs are connected by a crossbeam.

[0045] Three pairs of microwave transceiver antennas are arranged opposite to each other on the inner sides of the two legs, forming left and right microwave antenna groups that transmit and receive each other; each antenna uses a narrow beam design, and the middle antenna beam is slightly wider, which can accurately irradiate the material and reduce spatial interference.

[0046] The left antenna group 2, the right antenna group 4, the left transceiver 3, and the right transceiver 5 together form a microwave scanning transceiver system. The left and right antenna groups can transmit and receive multiple signals at each scanning point, forming microwave paths for direct transmission reception, cross transmission reception, and reflection reception, thereby realizing spatially distributed microwave detection.

[0047] The two legs can move horizontally along the set direction on the horizontal track 10; the inner sides of the two legs are respectively provided with vertical lifting mechanisms 1 along the direction of the legs, and the left and right antenna groups are respectively arranged on the vertical lifting mechanisms 1. Through the horizontal movement of the legs and the lifting and lowering of the vertical lifting mechanism 1, the antenna group can be driven to move to achieve full-range scanning of the material.

[0048] In addition, ultrasonic ranging sensors 6 and temperature and humidity sensors 11 are respectively provided on the two legs and the top beam. The left and right ranging sensors are used to measure the material width, and the ranging sensor on the beam is used to measure the material height. The temperature and humidity sensor 11 is used to measure the temperature and humidity of the environment to eliminate its influence on microwave measurement.

[0049] The main controller 12 is configured to plan a scanning trajectory according to the range of the material to be detected to control the horizontal movement and vertical lifting of the microwave antenna group; at the same time, the microwave antenna group is controlled to transmit once at each scanning point, and the remaining antennas receive at the same time.

[0050] In this embodiment, the horizontal movement of the legs and the lifting and lowering of the vertical lifting mechanism 1 are driven by the PLC controller 8. The PLC controller 8 is connected to the main controller 12, receives the movement path instructions of the main controller 12, and controls the horizontal movement of the legs and the lifting and lowering of the vertical lifting mechanism 1 according to the instructions.

[0051] The ultrasonic distance sensor 6 and the temperature and humidity sensor 11 are respectively connected to the acquisition controller 7, and the acquisition controller 7 communicates with the main controller 12. The main controller 12 receives the measurement data of the left and right distance sensors and the temperature and humidity sensor 11, and based on the width and height of the material measured by the distance sensor, combined with the pre-stored vehicle model data, forms a scanning path of the microwave antenna group to realize automatic positioning scanning; and the scanning trajectory and the beam width of each antenna are coordinated to ensure that the material range is scanned just right, avoiding interference of invalid scanning areas.

[0052] While the antenna moves to complete the microwave scan, the size of the material is also measured, thus providing a clear description of the detection space and the relative relationship between the antenna and the material.

[0053] According to the scanning trajectory, a control instruction for driving the movement path of the antenna group is generated and sent to the PLC controller 8. The PLC controller drives the horizontal movement of the legs and the lifting and lowering of the vertical lifting mechanism 1 according to the control instruction, driving the antenna group to move along the scanning trajectory, thereby ensuring a comprehensive scan.

[0054] Figures 4(a)-(c) are respectively schematic diagrams of vertical cross-sections of the scanning trajectory in an embodiment of the present invention; they illustrate the working conditions of other antenna groups when the middle antenna of antenna array B is transmitting. The three circles in Figure 4(a) represent the antenna array on the left, which is currently in the receiving state; the three circles in Figure 4(b) represent the antenna array on the right, where the middle antenna is currently in the transmitting state and the upper and lower antennas are in the receiving state. The energy value measured by the left receiving antenna is the projection attenuation after the microwave passes through the material being measured, and the energy value measured by the upper and lower receiving antennas on the right is the reflection value after the microwave irradiates the material being measured.

[0055] In this embodiment, at each scanning point, three pairs of antenna groups have a total of 6 antennas, and each antenna is used as a transmitting end to transmit once in turn. While each antenna is transmitting, the other 5 antennas receive simultaneously, forming direct transmission reception, cross transmission reception and reflection reception, ensuring that transmission and reflection are taken into account; each antenna is used as a transmitting end in turn, so that the same area of ​​the material is irradiated by microwaves in 6 different directions and transmission and reflection are formed, thus comprehensively and accurately describing the spatial influence of the moisture content of each area of ​​the material on the microwave.

[0056] 3(a)-(f) respectively show schematic diagrams of antenna transmission and reception in which one antenna transmits and the other antennas receive, wherein reference numeral 1 represents a transmitted wave, reference numeral 2 represents a reflected wave, and reference numeral 3 represents a transmitted wave.

[0057] It can be seen that when the remaining antennas are used as receiving ends, they can respectively realize direct transmission reception, cross transmission reception and reflection reception.

[0058] Embodiment 2

[0059] In one or more embodiments, an online microwave moisture detection method is disclosed, comprising the following steps:

[0060] (1) Plan the scanning trajectory according to the chassis direction of the transport vehicle and the material loading height;

[0061] (2) Control the moving path of the microwave antenna group according to the scanning trajectory to ensure full scanning of the material range;

[0062] The scanning trajectory is planned according to the chassis direction and material loading height of different transport vehicles to form the moving path of the antenna, realize comprehensive scanning of materials, and avoid the influence of non-material areas and chassis metal.

[0063] (3) At each scanning point, each antenna in the microwave antenna group is controlled to transmit once in turn, and the remaining antennas receive at the same time, so that the same area of ​​the material is irradiated with microwaves in different directions and forms transmission and reflection reception;

[0064] At the same scanning point, a single antenna transmits in turn, and other antennas receive to form direct transmission reception, cross transmission reception and reflection reception. Each antenna completes a single point scan after one transmission and multiple receptions.

[0065] (4) Measure the value and phase of microwave emission and reception, and calculate the moisture content of each section.

[0066] In this embodiment, the solution model formed by many parameters such as microwave frequency, intensity, phase, transmission, reflection, material width, height, position relationship between antenna and material, temperature, humidity, etc. is implemented in the form of a neural network, and calibration is achieved through a training self-learning process.

[0067] The transceiver antenna arrays are arranged on both sides of the vehicle or the object under test, with one end transmitting microwaves and the other end receiving them. The equipment automatically measures and records the energy value and phase difference of microwave transmission and reception, and simultaneously measures the temperature and humidity through the temperature and humidity sensor 11, and uses the distance sensor to measure the three-dimensional shape indicators of the goods under test, and calculates the moisture content of the goods in the vehicle under test based on the microwave medium propagation attenuation and polarization reaction principle.

[0068] The calculation process uses a neural network regression algorithm, based on a large amount of measurement data of the standard test piece in the early stage, to obtain the linear relationship between the above parameters such as energy value, phase difference, temperature and humidity, shape and moisture content. In specific applications, according to no-load calibration and true value calibration, the installation error is determined and the weight parameter in the linear relationship is corrected. Finally, the actual measured value is given.

[0069] In this embodiment, 6 groups of energy and phase values ​​can be obtained by using the antenna array, each group includes 3 transmission values ​​and 2 reflection values, and the transmission values ​​include both horizontal attenuation values ​​and diagonal attenuation values. The transmitting end and the receiving end of each group of measurement values ​​are respectively located at different positions of the measured object. According to the theory of electromagnetic wave transmission in lossy media, neural network regression calculation is performed on each measurement result of the standard test piece to obtain the attenuation constant of the standard test piece. In practical applications, due to the distribution of moisture in the test piece, the measured energy and phase values ​​change. By comparing with the standard test piece, the anisotropic change of the attenuation constant of the test piece can be obtained. By vector calculation, the distribution change of the moisture content of the cross section of the test piece can be characterized.

[0070] (5) The interface formed at each experience point in the scanning direction is refined into multiple areas and distinguished by different colors representing moisture content, forming a moisture content thermodynamic map of the material spatial distribution, and calculating the average moisture content at the same time.

[0071] The specific implementation process of the method in this embodiment has been described in detail in the first embodiment and will not be repeated here.

[0072] This embodiment can truly realize the online automatic detection of the moisture content of the whole vehicle materials (paper bags, wood chips, tobacco, grain and other non-metallic materials), adapt to various vehicle models and material packaging forms, do not need to unload materials, and the detection process is fully automatic.

[0073] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. An online microwave moisture detection method, characterized in that: include: Plan the scanning trajectory according to the chassis direction of the transport vehicle and the material loading height; Control the moving path of the microwave antenna group according to the scanning trajectory to ensure full scanning of the material range; At each scanning point, each antenna in the microwave antenna group is controlled to transmit once in turn, and the other antennas receive at the same time, so that the same area of ​​the material is irradiated with microwaves in different directions and forms transmission and reflection reception; specifically, at the same scanning point, a single antenna is allowed to transmit in turn, and the other antennas receive to form direct transmission reception, cross transmission reception and reflection reception. Each antenna undergoes one transmission and multiple receptions to complete a point scan; The microwave emission and reception values ​​and phases are measured, and the moisture content of each cross section is calculated. Specifically, a neural network regression algorithm is used to obtain the linear relationship between energy value, phase difference, temperature and humidity, shape parameters and moisture content based on a large amount of measurement data of previous standard test pieces.

2. An online microwave moisture detection method as claimed in claim 1, characterized in that: Measure the microwave emission and reception values ​​and phases, and calculate the moisture content of each section. The specific process includes: The transceiver antenna arrays are arranged on both sides of the vehicle or the object under test, with one end emitting microwaves and the other end receiving them. The equipment automatically measures and records the energy value and phase difference of microwave emission and reception, and simultaneously measures the temperature and humidity through temperature and humidity sensors, and uses distance sensors to measure the three-dimensional shape indicators of the goods under test. Based on the microwave medium propagation attenuation and polarization reaction principles, the moisture content in the goods in the vehicle under test is calculated.

3. An online microwave moisture detection method as claimed in claim 2, characterized in that: The interface formed at each experience point in the scanning direction is refined into multiple areas and distinguished by different colors representing moisture content, forming a thermal map of moisture content distributed in the material space.

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