Microcapsule spraying control method and system based on multi-sensor monitoring

Abstract

The invention discloses a micro-capsule spraying control method and system based on multi-sensor monitoring, and relates to the technical field of micro-capsule spraying monitoring. The method comprises the following steps: firstly, establishing a temperature correction model of micro-capsule particles, transmitting and receiving orthogonal coding microwave signals through a double-layer loop antenna array deployed on the outer wall of a granulation chamber, demodulating the received mixed signals, obtaining a plurality of channel matrixes, and calculating complex dielectric constant distribution data of a plurality of section positions; and correcting the complex dielectric constant distribution data by synchronously combining the instantaneous temperature of each section position acquired by a temperature sensor, and converting the corrected complex dielectric constant distribution data into an instantaneous section image. Finally, the working parameters of the primary medium and the secondary medium are dynamically adjusted through the characteristic difference between the instantaneous cross-section image and the standard cross-section image, the problems of response lag and measurement distortion of a traditional detection method in a high-temperature dynamic environment are solved, and accurate online monitoring and closed-loop control of the micro-capsule granulation process are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of microcapsule spray monitoring, and particularly to a microcapsule spray control method and system based on multi-sensor monitoring. Background Art

[0002] Water molecules have strong dielectric response characteristics to microwaves and can highly sensitively reflect the humidity change of microcapsule particles through the resonance frequency shift and signal attenuation change, realizing non-contact on-line measurement. Chinese Patent Application with Publication No. CN114324096A discloses an on-line detection method for particle concentration distribution and humidity during the fluidized bed drying process. This method measures the change in the frequency of the microwave resonator cavity, combines the dielectric model and image reconstruction technology, and inversely calculates the particle concentration and humidity distribution in the fluidized bed on-line. However, the microwave resonator cavity only provides the global average dielectric constant and cannot distinguish the information of different cross-sections. It needs to rely on the distribution of ECT for iterative calibration, and the spatial resolution of ECT is low and is easily affected by the initial error, resulting in error accumulation. Chinese Patent Application with Publication No. CN118226444A discloses a microwave imaging method and system, a transmitting and receiving terminal, and a computer-readable medium. This method obtains the microwave signal and position information scattered by the target through the circumvention of the receiving terminal, and realizes the cross-section imaging of the target through spectral analysis and inverse calculation. However, the single-antenna scanning imaging adopted by this method requires mechanical rotation or array switching, has a slow imaging speed, cannot capture the dynamic spray transient change, resulting in a time difference between the monitoring result and the actual state. Moreover, the high-temperature environment easily causes the dielectric constant of the target to drift, and this method lacks a real-time dielectric compensation mechanism, easily leading to image distortion of the cross-section imaging. Therefore, it is necessary to further improve the existing technology. Summary of the Invention

[0003] In view of the above problems, the present invention provides a microcapsule spray control method and system based on multi-sensor monitoring. This method realizes single-frame instantaneous imaging through a double-layer circular antenna array and orthogonally encoded microwave signals, and then combines a temperature sensor to perform real-time compensation on the dielectric constant, accurately correcting the influence of the high-temperature environment on the propagation of microwave signals, so as to obtain a high-precision instantaneous cross-section image inside the granulation chamber.

[0004] The invention object of the present application can be achieved by the following technical means: A microcapsule spray control method based on multi-sensor monitoring, comprising the following steps: Step 1: Deploy a double-layer circular antenna array and a temperature sensor at multiple cross-section positions on the outer wall of the granulation chamber. Each group of double-layer circular antenna arrays includes multiple groups of outer-ring transmitting antennas and inner-ring receiving antennas; Step 2: Measure the complex dielectric constant of standard microcapsule particles at different instantaneous temperatures, construct a temperature correction model, and preset the template features of the granulation chamber at multiple working durations; Step 3: Prepare a suspension material using an oil-based core material and an aqueous wall material, spray the suspension material into the granulation chamber, convey a primary medium to the granulation chamber, and recover a secondary medium from the granulation chamber; Step 4: Each group of transmitting antennas simultaneously transmits orthogonally encoded microwave signals, and the corresponding receiving antennas synchronously collect the mixed signals; Step 5: Demodulate each group of mixed signals to obtain a plurality of channel matrices, and calculate the complex permittivity distribution data at a plurality of cross-sectional positions based on the channel matrices; Step 6: A temperature sensor collects the instantaneous temperature at a plurality of cross-sectional positions, and corrects the complex permittivity distribution data at the corresponding cross-sectional positions according to the instantaneous temperature and the temperature correction model; Step 7: Extract the permittivity of the complex permittivity distribution data, and convert the complex permittivity distribution data into an instantaneous cross-sectional image based on the permittivity; Step 8: Extract a standard cross-sectional image from the template features, calculate the feature difference between the instantaneous cross-sectional image and the standard cross-sectional image, and adjust the working parameters of the primary medium and the secondary medium according to the feature difference.

[0005] In the present invention, in Step 2, the complex permittivity ε = ε' + jε'', and the temperature correction model is: And , where the real part ε' is the permittivity, the imaginary part ε'' is the loss factor, Δε' is the real part change of the real part ε', Δε'' is the imaginary part change of the imaginary part ε'', j is the imaginary unit, ε'0 is the permittivity of the standard microcapsule particles at the reference temperature, ε''0 is the loss factor of the standard microcapsule particles at the reference temperature, T is the instantaneous temperature, T0 is the reference temperature, α is the real part temperature coefficient, and β is the imaginary part temperature coefficient.

[0006] In the present invention, in Step 3, the oil-based core material is plant essential oil, the thymol in the plant essential oil is ≥13.5 wt%, the cinnamaldehyde is ≥6.5 wt%, the aqueous wall material is an aqueous solution of dextrin and starch, and the mass ratio of the oil-based core material to the aqueous wall material in the suspension material is 1:4 to 1:6.

[0007] In the present invention, in Step 5, the cross-section of the granulation chamber is discretized into a pixel grid, based on the initial complex permittivity of the pixel grid, a theoretical channel matrix H' is generated by a forward simulation algorithm, an error function between the channel matrix H and the theoretical channel matrix H' is constructed, and the complex permittivity ε of each pixel grid is gradually updated by solving the error function, and finally the complex permittivity distribution data is generated.

[0008] In the present invention, in step 6, according to the temperature correction model and the instantaneous temperature, the real part change amount Δε' and the imaginary part change amount Δε'' are obtained. The complex permittivity change amount Δε = Δε' + jΔε''. The complex permittivity change amount Δε of the complex permittivity distribution data is removed to obtain the corrected complex permittivity distribution data.

[0009] In the present invention, in step 7, the permittivity range is calculated. According to the permittivity range, each permittivity in the complex permittivity distribution data is mapped to a gray value to obtain an instantaneous cross-sectional image.

[0010] In the present invention, in step 8, the gray value differences between the instantaneous cross-sectional images at each cross-sectional position and the corresponding standard cross-sectional images are calculated respectively, and then the characteristic differences of the granulation chamber are obtained.

[0011] In the present invention, in step 8, a parameter template is preset. The parameter template includes the working parameters of the primary medium and the secondary medium for multiple working durations. If the absolute value of the characteristic difference is greater than the difference threshold D1, the working parameters of the primary medium and the secondary medium are adjusted, and at the same time, the adjustment amplitude of each working parameter is calculated.

[0012] A spray control system for implementing the microcapsule spray control method based on multi-sensor monitoring includes: a granulation chamber, a temperature sensor, a hot air device, a double-layer circular antenna array, a parameter controller, a data processing unit, and a data analysis unit. Among them, The granulation chamber is configured to accommodate suspension materials; The hot air device is configured to output a primary medium to the granulation chamber and recover a secondary medium; The temperature sensor is configured to collect the instantaneous temperatures at multiple cross-sectional positions of the granulation chamber; The double-layer circular antenna array is configured to transmit microwave signals to the granulation chamber and collect mixed signals; The data processing unit is configured to generate an instantaneous cross-sectional image according to the mixed signal and the instantaneous temperature, and generate the characteristic difference between the instantaneous cross-sectional image and the standard cross-sectional image; The data analysis unit is configured to generate an adjustment instruction according to the characteristic difference; The parameter controller is configured to adjust the working parameters of the primary medium and the secondary medium according to the adjustment instruction.

[0013] In the present invention, the granulation chamber has an atomizing nozzle and a rotating wall. The material flow rate, atomizing pressure, and rotational speed of the rotating wall of the suspension material are adjusted according to the equivalent diameter of the particle contour in the granulation chamber.

[0014] Implementing the microcapsule spray control method and system based on multi-sensor monitoring of the present invention has the following beneficial effects: First, through the double-layer circular antenna array combined with the orthogonal-coded microwave signal, single-frame instantaneous imaging is achieved, generating instantaneous complex permittivity distribution data, solving the problem of the lag in dynamic response of traditional microwave imaging, and being able to accurately capture the transient changes of microcapsule particles. Then, according to the temperature sensor, the instantaneous temperature is obtained in real time, and the complex permittivity in the complex permittivity distribution data is corrected based on the instantaneous temperature to compensate for the influence of the high-temperature environment on the microwave signal, improving the accuracy of the complex permittivity distribution data. In addition, through the comparison between the standard cross-sectional images and the instantaneous cross-sectional images at multiple cross-sectional positions, the closed-loop control of the primary medium and the secondary medium is achieved, ensuring the uniformity and stability of microcapsule particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flowchart of the microcapsule spray control method based on multi-sensor monitoring of the present invention; Figure 2 is a schematic diagram of the double-layer circular antenna array; Figure 3 is an instantaneous cross-sectional image of the present invention; Figure 4 is another instantaneous cross-sectional image of the present invention; Figure 5 is a schematic diagram of multiple groups of template features of the present invention; Figure 6 is a block diagram of the spray control system of the present invention; Figure 7 is a schematic diagram of the granulation chamber of the present invention; Figure 8 is a schematic diagram of the microcapsule granulation production line of the present invention.

[0016] Reference numerals in the drawings: granulation chamber 10, material bin 11, finished product bin 12, cyclone collector 13, medium bin 14, heat exchanger 15, pressure pump 16, first controller 21, second controller 22, third controller 23, fourth controller 24, fifth controller 25, sixth controller 26. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0018] In the industrial production process of microcapsule particles, accurate detection and control of the humidity of microcapsule particles is a key factor in ensuring product quality. The appropriate humidity level directly affects the molding quality, encapsulation rate and product stability of microcapsules. However, the existing microcapsule humidity detection technology has significant limitations: the traditional offline sampling detection method (such as the drying loss method) is not only poor in timeliness, but also destroys the continuity of production; although the near-infrared spectroscopy method can realize online detection, there is a signal saturation phenomenon in the high-concentration suspension system, and the detection error of microcapsules with a particle size of less than 50μm is too large; although the capacitance tomography technology has a fast response, it is limited by the nonlinear relationship between the dielectric constant and humidity, and the measurement accuracy drops sharply in a high temperature environment. These methods cannot meet the needs of real-time and accurate monitoring of the microcapsule granulation process. In response to the above problems, the present invention combines orthogonal coded microwave tomography with a distributed temperature sensing network, realizes millisecond-level high-speed imaging through a double-layer ring antenna array, and cooperates with a pre-built temperature correction model to compensate for the influence of the high temperature environment on humidity measurement in real time, and realizes high-precision dynamic detection of the humidity of microcapsule particles. Embodiment 1

[0019] Reference Figure 1 The microcapsule spray control method based on multi-sensor monitoring of the present invention described in detail in this embodiment includes the following steps.

[0020] Step 1: Deploy double-layer loop antenna arrays and temperature sensors at multiple cross-sectional locations on the outer wall of the granulation chamber. Each set of double-layer loop antenna arrays includes multiple sets of outer-ring transmitting antennas and inner-ring receiving antennas. Figure 2 , a group of double-layer annular antenna arrays are deployed at each cross-sectional position, the number of transmitting antennas is 8 to 24, the number of receiving antennas is 16 to 48, the radial spacing between the receiving antenna and the transmitting antenna is 1.5-2 times the wall thickness of the granulation chamber, and the axial spacing of the double-layer annular antenna arrays at adjacent cross-sectional positions is 0.3-1.2 times the diameter of the granulation chamber. In this embodiment, there are four groups of double-layer annular antenna arrays, the transmitting antenna adopts a microstrip patch antenna, the microstrip patch antenna is fixed by a high-temperature resistant ceramic substrate, the receiving antenna is a spiral antenna, the spiral antenna is fixed by a stainless steel bracket, and a silicone rubber insulation layer is filled between the stainless steel bracket and the outer wall of the granulation chamber. Each group of double-layer annular antenna arrays corresponds to at least one temperature sensor, and the temperature sensor is, for example, a thermocouple sensor.

[0021] Step 2: Measure the complex permittivity of standard microcapsule particles at different instantaneous temperatures, construct a temperature correction model, and preset the template features of the granulation chamber at multiple working durations. The humidity of the standard microcapsule particles is less than or equal to 1%. The low humidity can avoid the interference of moisture on the complex permittivity during the construction of the temperature correction model. Use, for example, a dielectric spectrometer to scan the standard microcapsule particles at different instantaneous temperatures. The complex permittivity ε = ε'+jε'', record the real part ε' and the imaginary part ε'' of the complex permittivity of the standard microcapsule particles at each instantaneous temperature, and calculate the real part change Δε' of the real part ε' and the imaginary part change Δε'' of the imaginary part ε''. Establish a temperature correction model: and , where the real part ε' is the permittivity, the imaginary part ε'' is the loss factor, j is the imaginary unit, ε'0 is the permittivity of the standard microcapsule particles at the reference temperature, ε''0 is the loss factor of the standard microcapsule particles at the reference temperature, T is the instantaneous temperature, T0 is the reference temperature, α is the real part temperature coefficient, and β is the imaginary part temperature coefficient. The reference temperature T0 is, for example, 25 °C.

[0022] Step 3: Prepare a suspension material using an oily core material and an aqueous wall material, inject the suspension material into the granulation chamber, convey a primary medium into the granulation chamber, and recover a secondary medium from the granulation chamber. The oily core material is plant essential oil, and in the plant essential oil, thymol ≥ 13.5 wt%, cinnamaldehyde ≥ 6.5 wt%. The aqueous wall material is an aqueous solution of dextrin and starch. The mass ratio of the oily core material to the aqueous wall material in the suspension material is 1:4 to 1:6. The primary medium is a high-temperature gas medium (air or nitrogen) entering the granulation chamber, and the secondary medium is the gas medium discharged from the granulation chamber, which contains volatile gaseous water and a small amount of residual microcapsule particles.

[0023] Step 4: Each group of transmitting antennas simultaneously transmits orthogonally encoded microwave signals, and the corresponding receiving antennas synchronously collect the mixed signals. The orthogonally encoded microwave signals can be generated by any one of frequency-division orthogonality, code-division orthogonality, or time-division orthogonality. In this embodiment, frequency-division orthogonality is used to generate orthogonally encoded microwave signals. Each group of transmitting antennas simultaneously transmits orthogonally encoded (different frequencies) microwave signals, and the mixed signal is the superposition of the signals of all transmitting antennas. The specific generation method of the microwave signals refers to Embodiment 2.

[0024] Step 5: Demodulate each group of mixed signals to obtain a plurality of channel matrices, and calculate the complex permittivity distribution data at a plurality of cross-sectional positions according to the channel matrices. Separate the mixed signals through fast Fourier transform (FFT) to generate a channel matrix H. Discretize the cross-section of the granulation chamber into a pixel grid, and generate a theoretical channel matrix H' based on the initial complex permittivity of the pixel grid. The dimensions of the theoretical channel matrix and the channel matrix are the same. Construct an error function between the channel matrix H and the theoretical channel matrix H': min||H - H'(ε)||2 +λ||▽ε|| 2 , solve the error function, gradually optimize the complex permittivity ε of each pixel grid, and finally generate the complex permittivity distribution data. Among them, λ is the regularization parameter, H'(ε) is the theoretical channel matrix obtained based on the complex permittivity ε, and ▽ε is the spatial gradient of the complex permittivity. For the specific implementation manner, refer to Embodiment 2.

[0025] Step 6: The temperature sensor collects the instantaneous temperatures at multiple cross-section positions, and corrects the complex permittivity distribution data at the corresponding cross-section positions according to the instantaneous temperatures and the temperature correction model. Obtain the real part change amount Δε' and the imaginary part change amount Δε'' according to the temperature correction model and the instantaneous temperature. The complex permittivity change amount Δε = Δε' + jΔε''. Eliminate the complex permittivity change amount Δε of the complex permittivity distribution data to obtain the corrected complex permittivity distribution data.

[0026] Step 7: Extract the permittivity of the complex permittivity distribution data, and convert the complex permittivity distribution data into an instantaneous cross-section image based on this permittivity. Set the humidity range, obtain the permittivity range according to the humidity range, and map each permittivity in the complex permittivity distribution data to a gray value according to the permittivity range to obtain the instantaneous cross-section image. Such as Figure 3 and Figure 4 , the change of the gray value of the instantaneous cross-section image can reflect the humidity distribution of the microcapsule particles in the granulation chamber, and the gray value is positively correlated with the permittivity ε'.

[0027] In this embodiment, the humidity range is set to (0%, 100%). The permittivity ε' of water is about 80, and the permittivity ε' of the dry material is about 2. Then the permittivity range is (2, 80). The complex permittivity ε of each pixel grid in the complex permittivity distribution data is ε = ε' - jε''. Map the permittivity ε' to an instantaneous cross-section image with 256 levels of gray through piecewise linearity: when ε' < 2, the gray value G is set to 0 (pure black); when 20 > ε' ≥ 2, the gray value G = round(12.75×ε' - 25.5); when 80 > ε' ≥ 20, the gray value G = round(2.55×ε' + 178.5); when ε' ≥ 80, the gray value G is set to 255 (pure white), and finally generate the instantaneous cross-section image.

[0028] In another embodiment, the humidity of the suspended material is taken as the maximum humidity, and the humidity of the standard microcapsule particles is taken as the minimum humidity. The humidity of the suspended material is 40%, and the humidity of the standard microcapsule particles is 1%. Then the humidity range is (1%, 40%), and the dielectric constant range is (2.5, 50). The dielectric constant ε' is linearly mapped to an instantaneous cross-sectional image of 256 gray levels: when ε'<2.5, the gray value G is set to 0; when 50>ε'≥2.5, G = round(5.36×(ε'-2.5)); when ε'≥50, the gray value G is set to 255, and an instantaneous cross-sectional image is generated.

[0029] Step 8: Extract the standard cross-sectional image from the template features, calculate the feature difference between the instantaneous cross-sectional image and the standard cross-sectional image, and adjust the working parameters of the primary medium and the secondary medium according to the feature difference. Obtain multiple groups of instantaneous cross-sectional images, calculate the gray value difference between the instantaneous cross-sectional image at each cross-sectional position and the corresponding standard cross-sectional image respectively, and take the average value of the multiple groups of gray value differences as the feature difference of the granulation chamber. Preset a parameter template, which includes the working parameters of the primary medium and the secondary medium for multiple working durations. If the absolute value of the feature difference is greater than the difference threshold D1, adjust the working parameters of the primary medium and the secondary medium, and calculate the adjustment amplitude of each working parameter at the same time. Specifically, refer to Embodiment III. Set the difference threshold D1 according to the production process requirements. In this embodiment, the feature difference is calculated based on the pixel gray value (0 to 225) as the basic unit, and the setting range of D1 is 10-30. Embodiment II

[0030] This embodiment further discloses a method for generating microwave signals by frequency division orthogonalization and generating complex dielectric constant distribution data. The microcapsule particles in the granulation chamber are in a state of high-speed movement. Frequency division orthogonalization can avoid movement interference by generating microwave signals of different frequencies, and is suitable for the high-speed dynamic environment of the present invention.

[0031] Determine the center frequency. Based on the radius R of the granulation chamber and the loss factor ε'' of the microcapsule particles, select the center frequency f' of the microwave signal. The range of the center frequency is usually 1-5 GHz (corresponding to R = 0.25-1.5 meters), and the specific calculation formula is , where c is the speed of light, and ε'' reflects the absorption characteristics of the microcapsule particles to the microwave signal. The double-layer circular antenna array on the outer wall of the granulation chamber includes N transmitting antennas in the outer circle and M receiving antennas in the inner circle. The spacing between the transmitting antennas and between the receiving antennas is usually less than 5 cm.

[0032] Construct the channel matrix. Determine the total bandwidth B, satisfying B>2v max f' / c, where v max(estimated according to the maximum medium flow velocity of the primary medium) is the maximum movement speed of the microcapsule particles. The total bandwidth B is evenly divided into K orthogonal subcarriers (interval Δf = B / K), that is, the frequency f of the k-th orthogonal subcarrier k = f' - B / 2 + (k - 1)Δf. Then, the K orthogonal subcarriers are evenly divided into N subcarrier groups (K mod N = 0). Each subcarrier group contains multiple consecutive orthogonal subcarriers, and each transmitting antenna is assigned a unique subcarrier group. The transmitting antenna generates a microwave signal based on the assigned subcarrier group and transmits it simultaneously. The receiving antenna synchronously collects the mixed signal and demodulates the mixed signal through the fast Fourier transform algorithm to separate the channel response H corresponding to each orthogonal subcarrier i,n,m , and constructs an I×N×M-dimensional channel matrix H, where I = K / N, and H i,n,m represents the channel response between the orthogonal subcarrier i, the transmitting antenna n, and the receiving antenna m, i = 1, 2,..., I, n = 1, 2,..., N, m = 1, 2,..., M.

[0033] Generate complex permittivity distribution data. Discretize the cross-section of the granulation chamber into a pixel grid, and set an initial complex permittivity for each pixel grid. In this embodiment, according to the initial complex permittivity, the number N of transmitting antennas, the number M of receiving antennas, and the number I of orthogonal subcarriers of each transmitting antenna, a forward propagation model is constructed. Through this forward propagation model, the theoretical channel response under each propagation path is calculated, thereby constructing an I×N×M-dimensional theoretical channel matrix H'. In another embodiment, the finite element method is used to solve Maxwell's equations to simulate the propagation of microwave signals under the current initial complex permittivity and calculate the theoretical channel matrix H'. Construct an error function min||H - H'(ε)|| 2 + λ||▽ε|| 2 , solve this error function, and finally obtain the complex permittivity ε of each pixel grid to generate complex permittivity distribution data, where H'(ε) is the theoretical channel matrix calculated by forward modeling based on the complex permittivity ε, λ is the regularization parameter, and ▽ε is the spatial gradient of the complex permittivity. Embodiment 3

[0034] As Figure 5 , this embodiment further discloses a preferred method for adjusting the working parameters of the primary medium and the secondary medium in step 8. The working parameters of the primary medium include the medium flow velocity V1 and the medium temperature T', and the working parameter of the secondary medium is the medium pressure F1. The standardized operation process of microcapsule spray granulation mainly includes four stages: preheating, curing, fluidization, and collection. The present invention mainly focuses on the spray control in the curing stage. Therefore, a preferred parameter template includes at least the working parameters in the curing stage, as shown in the following table (the unit of the working duration t is min).

[0035]

[0036] In this embodiment, four groups of double-layer circular antenna arrays are arranged on the outer wall of the granulation chamber, and four groups of instantaneous cross-sectional images are generated for each working period. Calculate the mean gray value μ1 of each group of instantaneous cross-sectional images and the mean gray value μ2 of the corresponding standard cross-sectional image to obtain the gray value difference Δμ = μ1 - μ2. Take the average value of the four groups of gray value differences Δμ as the feature difference Δ1. If the absolute value of the feature difference is greater than the difference threshold D1, calculate the adjustment parameter δ1 = Δ1 / 255, then the adjustment amplitude of the medium flow rate ΔV1 = δ1V1, the adjustment amplitude of the medium temperature ΔT = δ1T', and the adjustment amplitude of the medium pressure ΔF1 = δ1F1. Adjust the primary medium and the secondary medium once according to the adjustment amplitude. Embodiment Four

[0037] As Figure 6 , the spray control system for implementing the microcapsule spraying control method based on multi-sensor monitoring of the present invention includes: a granulation chamber, a temperature sensor, a hot air device, a double-layer circular antenna array, a parameter controller, a data processing unit, and a data analysis unit. Among them, the granulation chamber is configured to accommodate the suspension material. The hot air device is configured to output the primary medium to the granulation chamber and recover the secondary medium. The temperature sensor is configured to collect the instantaneous temperature at multiple cross-sectional positions in the granulation chamber. The double-layer circular antenna array is configured to transmit microwave signals to the granulation chamber and collect the mixed signals. The data processing unit is configured to generate instantaneous cross-sectional images based on the mixed signals and the instantaneous temperature, and generate the feature difference between the instantaneous cross-sectional images and the standard cross-sectional images. The data analysis unit is configured to generate adjustment instructions based on the feature difference. The parameter controller is configured to adjust the working parameters of the primary medium and the secondary medium according to the adjustment instructions. As Figure 7 , the granulation chamber has an atomizing nozzle and a rotating wall, and adjusts the material flow rate, atomizing pressure, and rotation speed of the rotating wall of the suspension material according to the equivalent diameter of the particle contour in the granulation chamber.

[0038] As Figure 8The microcapsule granulation production line to which the shown spray control system is applied. The material bin 11 feeds the suspended material mixed with the oily core material and the aqueous wall material into the granulation chamber 10. The pressure pump 16 sprays the primary medium into the granulation chamber 10. The finished product bin 12 recovers the microcapsule particles. The cyclone recovery device 13 recovers the secondary medium. The microcapsule particles remaining in the secondary medium are recycled to the finished product bin 12 again. The secondary medium returns to the pressure pump 16 after passing through the medium bin 14 and the heat exchanger 15. The parameter template consists of the working parameters of the primary medium and the secondary medium for multiple working hours. Specifically, the first controller 21 adjusts the material flow rate of the suspended material. The second controller 22 adjusts the atomization pressure of the suspended material. The third controller 23 adjusts the working parameters (medium flow rate) of the primary medium. The fourth controller 24 adjusts the working parameters (medium temperature) of the primary medium. The fifth controller 25 adjusts the working parameters (medium pressure) of the secondary medium. The sixth controller 26 adjusts the rotation speed of the rotary wall. Embodiment Five

[0039] Furthermore, the present invention can also adjust the working parameters of the suspended material and the rotary wall in the curing stage. Specifically, first, collect the vertical image in the granulation chamber, obtain the particle contour in the vertical image, calculate the equivalent diameter E of the particle contour by using, for example, the equivalent area method, and calculate the particle size difference Δ2 between the equivalent diameter E and the standard particle size E'. If the absolute value of the particle size difference is greater than the difference threshold D2, then adjust the working parameters of the suspended material and the rotary wall. The working parameters of the suspended material include the material flow rate V2 and the atomization pressure F2, and the working parameter of the rotary wall is the rotation speed Q. Calculate the adjustment parameter δ2 = Δ2 / E', then the adjustment range of the material flow rate ΔV2 = δ2V2, the adjustment range of the atomization pressure ΔF2 = δ2F2, and the adjustment range of the rotation speed ΔQ = δ2Q. Adjust the suspended material and the rotary wall according to this adjustment range.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A microcapsule spray control method based on multi-sensor monitoring, characterized in that, It includes the following steps: Step 1: Deploy a double-layer circular antenna array and temperature sensors at multiple cross-section positions on the outer wall of the granulation chamber. Each group of double-layer circular antenna arrays includes multiple groups of outer-ring transmitting antennas and inner-ring receiving antennas; Step 2: Measure the complex permittivity of standard microcapsule particles at different instantaneous temperatures, construct a temperature correction model, and preset the template features of the granulation chamber at multiple working durations; Step 3: Prepare a suspension material using an oily core material and an aqueous wall material, inject the suspension material into the granulation chamber, convey a primary medium to the granulation chamber, and recover a secondary medium from the granulation chamber; Step 4: Each group of transmitting antennas simultaneously transmits orthogonally encoded microwave signals, and the corresponding receiving antennas synchronously collect mixed signals; Step 5: Demodulate each group of mixed signals to obtain multiple channel matrices, and calculate the complex permittivity distribution data at multiple cross-section positions based on the channel matrices; Step 6: The temperature sensors collect the instantaneous temperatures at multiple cross-section positions, and correct the complex permittivity distribution data at the corresponding cross-section positions according to the instantaneous temperatures and the temperature correction model; Step 7: Extract the permittivity of the complex permittivity distribution data, and convert the complex permittivity distribution data into an instantaneous cross-section image based on the permittivity; Step 8: Extract the standard cross-section image from the template features, calculate the feature difference between the instantaneous cross-section image and the standard cross-section image, and adjust the working parameters of the primary medium and the secondary medium according to the feature difference; 2. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that, In step 2, the complex permittivity ε = ε'+ jε'', and the temperature correction model is: and , where the real part ε' is the permittivity, the imaginary part ε'' is the loss factor, Δε' is the real part change of the real part ε', Δε'' is the imaginary part change of the imaginary part ε'', j is the imaginary unit, ε'0 is the permittivity of the standard microcapsule particles at the reference temperature, ε''0 is the loss factor of the standard microcapsule particles at the reference temperature, T is the instantaneous temperature, T0 is the reference temperature, α is the real part temperature coefficient, and β is the imaginary part temperature coefficient.

3. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, wherein In Step 3, the oily core material is plant essential oil, wherein thymol in the plant essential oil is ≥13.5 wt%, cinnamaldehyde is ≥6.5 wt%, the aqueous wall material is an aqueous solution of dextrin and starch, and the mass ratio of the oily core material to the aqueous wall material in the suspension material is 1:4 to 1:6; 4. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that In Step 5, the cross-section of the granulation chamber is discretized into a pixel grid. Based on the initial complex permittivity of the pixel grid, a theoretical channel matrix H' is generated through a forward simulation algorithm, an error function between the channel matrix H and the theoretical channel matrix H' is constructed, and the complex permittivity ε of each pixel grid is gradually updated by solving the error function. Finally, the complex permittivity distribution data is generated; 5. The microcapsule spray control method based on multi-sensor monitoring according to claim 2, characterized in that, In Step 6, according to the temperature correction model and the instantaneous temperature, the real part change amount Δε' and the imaginary part change amount Δε'' are obtained. The complex permittivity change amount Δε = Δε' + jΔε''. The complex permittivity change amount Δε of the complex permittivity distribution data is removed to obtain the corrected complex permittivity distribution data; 6. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that In Step 7, calculate the permittivity range, and map each permittivity in the complex permittivity distribution data to a gray value according to the permittivity range to obtain an instantaneous cross-section image; 7. The microcapsule spray control method based on multi-sensor monitoring according to claim 6, characterized in that In Step 8, calculate the gray value difference between the instantaneous cross-section image and the corresponding standard cross-section image at each cross-section position respectively, and then obtain the feature difference of the granulation chamber; 8. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that In Step 8, preset a parameter template. The parameter template includes the working parameters of the primary medium and the secondary medium at multiple working durations. If the absolute value of the feature difference is greater than the difference threshold D1, adjust the working parameters of the primary medium and the secondary medium, and calculate the adjustment amplitude of each working parameter at the same time; 9. A spray control system for implementing the microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that, It includes: a granulation chamber, temperature sensors, hot air equipment, double-layer circular antenna arrays, a parameter controller, a data processing unit, and a data analysis unit, wherein, The granulation chamber is configured to accommodate suspended materials; The hot air device is configured to output a primary medium to the granulation chamber and recover a secondary medium; The temperature sensor is configured to collect the instantaneous temperatures at multiple cross-sectional positions in the granulation chamber; The double-layer annular antenna array is configured to transmit microwave signals to the granulation chamber and collect mixed signals; The data processing unit is configured to generate an instantaneous cross-sectional image based on the mixed signals and the instantaneous temperatures, and generate the feature differences between the instantaneous cross-sectional image and the standard cross-sectional image; The data analysis unit is configured to generate an adjustment instruction based on the feature differences; The parameter controller is configured to adjust the operating parameters of the primary medium and the secondary medium according to the adjustment instruction.

10. The spray control system according to claim 9, characterized in that, The granulation chamber has an atomizing nozzle and a rotating wall, and adjusts the material flow rate, atomizing pressure of the suspended materials, and the rotational speed of the rotating wall according to the equivalent diameter of the particle profile in the granulation chamber.

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