Raindrop diameter measuring method and raindrop diameter measuring device

Abstract

The invention discloses a raindrop diameter measuring method and a raindrop diameter measuring device, which are applied to the technical field of raindrop diameter measurement. The method comprises the following steps: preparing a super-hydrophobic surface with a cone frustum array; a binding force sensor and a raindrop diameter sensor designed on the super-hydrophobic surface; training a raindrop diameter prediction model based on a Gaussian process regression algorithm; arranging a raindrop diameter sensor at a to-be-measured point position; the raindrop diameter sensor collects the contact time and force values of raindrops and the super-hydrophobic surface; and inputting data acquired by the raindrop diameter sensor into the raindrop diameter prediction model to obtain a raindrop diameter measurement result. By introducing the super-hydrophobic coating on the surface of the sensor, the contact time of raindrops and the sensor is remarkably shortened, so that the signal trailing effect and the impact overlapping phenomenon are reduced, and the time resolution capability of a system on a single-drop raindrop impact event is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of raindrop diameter measurement, and more particularly to a raindrop diameter measurement method and a measuring device. Background Art

[0002] Currently, the laser raindrop spectrometer is the primary method for measuring raindrop diameter in meteorology. Based on the principle of light scattering, the laser raindrop spectrometer uses the light intensity attenuation signal caused by precipitation particles passing through a laser beam, combined with a pulse analysis algorithm, to invert the particle size, velocity, and type. The advantage of a laser raindrop spectrometer is its non-contact measurement capability, with millisecond-level time resolution and millimeter-level particle size resolution. However, its disadvantages include significant interference from optical window contamination and the inability to calibrate three-dimensional spatial parameters. Therefore, providing a raindrop diameter measurement method and device is a pressing issue for those skilled in the art. Summary of the Invention

[0003] In view of this, the present invention provides a raindrop diameter measurement method and measurement device, which uses a superhydrophobic layer to reduce the contact time between raindrops and sensors and improve the sampling rate of raindrops; by measuring the contact time of raindrops on the sensor and the force-time curve, a machine learning method is used to extract features to obtain the water droplet diameter.

[0004] In order to achieve the above object, the present invention provides the following technical solutions: A raindrop diameter measurement method comprises the following steps: S1. Preparation of a superhydrophobic surface with a truncated cone array; S2, designing a raindrop diameter sensor by combining force sensor and super-hydrophobic surface; S3, training a raindrop diameter prediction model based on the Gaussian process regression algorithm; S4, deploying the raindrop diameter sensor at the point to be measured; S5, a raindrop diameter sensor collects the contact time and force between the raindrop and the super-hydrophobic surface; S6. Input the data collected by the raindrop diameter sensor into the raindrop diameter prediction model to obtain a raindrop diameter measurement result.

[0005] Optionally, S1 is: S11, mixing PDMS prepolymer and cross-linking agent in a mass ratio of 8:1, stirring evenly and vacuuming for 30 minutes to remove bubbles; S12, fix the copper template with the truncated cone array square array structure on the spin coater suction cup, set the spin coating parameter to 600 r / s, and continue for 15 seconds to make the PDMS solution evenly distributed on the template surface; S13, after curing, the PDMS film was peeled off from the copper template, 0.4 g of titanium dioxide nanoparticles were mixed with 40 mL of anhydrous ethanol, the particles were evenly dispersed by ultrasonic treatment, and 400 μL of TMOS was added for surface modification; S14, fix the glass slide with the super-hydrophobic film on a spin coater, set the spin coating parameters to 1600 r / s, last for 45 seconds, and apply the nano-titanium dioxide solution; repeat 6-7 times; S15. Finally, the mixture was cured at 80°C for 2 hours to obtain a frustum-shaped square array super-hydrophobic surface.

[0006] Optionally, S3 specifically includes: constructing a model training feature set and using StandardScaler to standardize the input features; in the modeling process, selecting the product of the Rational Quadratic kernel function and the constant kernel as the kernel structure of the raindrop diameter prediction model, using 80% of the samples for fitting during training, and retaining 20% of the samples to verify the prediction ability.

[0007] Optionally, constructing a model training feature set specifically involves collecting force-time curve signals generated when raindrops hit a super-hydrophobic surface, extracting physical features, and simultaneously obtaining the diameter of water droplets by taking photos with a high-speed camera, manually marking them, and establishing a model training feature set.

[0008] A raindrop diameter measuring device includes a raindrop diameter sensor and a raindrop diameter prediction module. The raindrop diameter sensor is composed of a force sensor and a super-hydrophobic surface with a truncated cone array. The raindrop diameter sensor is used to collect the force-time curve signal generated when a raindrop hits the super-hydrophobic surface. The raindrop diameter prediction module outputs the predicted diameter of the raindrop based on the force-time curve signal and uses the predicted diameter of the raindrop as the measurement result.

[0009] It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a raindrop diameter measurement method and measurement device, which have the following beneficial effects: 1. Significantly improved measurement accuracy: When measuring raindrop diameters, the present invention maintains a control error range of less than 0.1%. Compared to the 3% to 5% error commonly seen in traditional laser raindrop spectrometers, the accuracy of the present invention is improved by an order of magnitude, greatly enhancing the reliability of the measurement data and its reference value for scientific research and engineering applications. 2. High sampling rate: By introducing a super-hydrophobic coating on the sensor surface, the present invention significantly reduces the contact time between raindrops and the sensor, thereby reducing the signal tailing effect and impact overlap, and effectively improving the system's time resolution capability for single raindrop impact events; 3. Good anti-interference ability: The present invention adopts mechanical signal acquisition to significantly reduce signal fluctuation interference caused by factors such as ambient light changes, obstructions, reflections, etc. It has strong adaptability and is particularly suitable for rainy and changeable light urban or mountainous environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0011] Figure 1 This is a flow chart of the raindrop diameter measurement method of the present invention; Figure 2 Schematic diagram of the super-hydrophobic surface structure of the present invention; Figure 3 Schematic diagram of the wettability and contact angle range of different surfaces in an embodiment of the present invention; Figure 4 The present invention is a flow chart for preparing a super-hydrophobic surface; Figure 5 Schematic diagram of the raindrop diameter sensor of the present invention; Figure 6 Schematic diagram of the droplet contact process on a super-hydrophobic surface in an embodiment of the present invention; Figure 7 4 is a force-time curve diagram in an embodiment of the present invention. DETAILED DESCRIPTION

[0012] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0013] The embodiment of the present invention discloses a method for measuring raindrop diameter. Figure 1 As shown, the following steps are included: S1. Prepare a super-hydrophobic surface with a truncated cone array; the super-hydrophobic surface structure is as follows Figure 2 As shown; S2. Design a raindrop diameter sensor by combining force sensor and super hydrophobic surface. The force sensor can measure the force in two directions and is used for the synthesis of the force on the inclined surface. Figure 5 As shown; S3, training a raindrop diameter prediction model based on the Gaussian process regression algorithm; S4, deploying the raindrop diameter sensor at the point to be measured; S5, a raindrop diameter sensor collects the contact time and force between the raindrop and the super-hydrophobic surface; S6. Input the data collected by the raindrop diameter sensor into the raindrop diameter prediction model to obtain a raindrop diameter measurement result.

[0014] Further, such as Figure 4 As shown, S1 is specifically: S11, mixing PDMS prepolymer and cross-linking agent in a mass ratio of 8:1, stirring evenly and vacuuming for 30 minutes to remove bubbles; S12, fix the copper template with the truncated cone array square array structure on the spin coater suction cup, set the spin coating parameter to 600 r / s, and continue for 15 seconds to make the PDMS solution evenly distributed on the template surface; S13, after curing, the PDMS film was peeled off from the copper template, 0.4 g of titanium dioxide nanoparticles were mixed with 40 mL of anhydrous ethanol, the particles were evenly dispersed by ultrasonic treatment, and 400 μL of TMOS was added for surface modification; S14, fix the glass slide with the super-hydrophobic film on a spin coater, set the spin coating parameters to 1600 r / s, last for 45 seconds, and apply the nano-titanium dioxide solution; repeat 6-7 times; S15. Finally, the mixture was cured at 80°C for 2 hours to obtain a frustum-shaped square array super-hydrophobic surface.

[0015] In an embodiment of the present invention, after a droplet hits a conical array of super-hydrophobic surfaces, it quickly detaches in a pancake-like manner. The contact time of the structure of this embodiment can be shortened to 2.8ms. The principle is that when a droplet contacts these structures, only a small part of the contact surface is in contact with the surface, and most of the droplet is suspended on the gas layer of the surface structure, thereby reducing the contact area of the droplet and significantly reducing the contact angle, achieving a super-hydrophobic effect. The wettability of different surfaces and their contact angle ranges are shown in Figure 3. The contact process between the droplet and the super-hydrophobic surface is shown in Figure 3. Figure 6 As shown; Furthermore, S3 is specifically as follows: constructing a model training feature set and using StandardScaler to standardize the input features; in the modeling process, selecting the product of the Rational Quadratic kernel function and the constant kernel as the kernel structure of the raindrop diameter prediction model, using 80% of the samples for fitting during training, and retaining 20% of the samples to verify the prediction ability.

[0016] In this embodiment of the present invention, the final trained model achieved a mean square error (MSE) of 0.0126 and a coefficient of determination (R²) of 0.9307 on the test set, demonstrating that the model has excellent performance in the raindrop diameter prediction task. In addition, the Gaussian process regression model can simultaneously output the predicted value and the corresponding uncertainty (standard deviation), providing a confidence indicator for subsequent system decision-making. After training is completed, the model and normalized parameters are serialized and saved together, making it easy to call in an embedded platform or back-end system to achieve real-time raindrop diameter estimation.

[0017] Furthermore, the model training feature set is constructed as follows: the force-time curve signal generated when raindrops hit the super-hydrophobic surface is collected, and the collection results are as follows: Figure 7 As shown, physical features are extracted, and the diameter of the water droplet is obtained by taking a high-speed camera, and manually marked to establish a model training feature set. In this embodiment of the present invention, the extracted physical features include maximum force value, impulse, contact time, tangential and normal force vectors.

[0018] Water droplet sensors are deployed between urban buildings. Raindrops of different diameters experience different contact times and peak forces with the sensors, resulting in unique force-displacement curves. By feeding these curves into a machine learning prediction file, the diameter of the raindrops can be determined.

[0019] An embodiment of the present invention also discloses a raindrop diameter measuring device, including a raindrop diameter sensor and a raindrop diameter prediction module. The raindrop diameter sensor is composed of a force sensor and a super-hydrophobic surface with a truncated cone array. The raindrop diameter sensor is used to collect the force-time curve signal generated during the process of raindrops hitting the super-hydrophobic surface. The raindrop diameter prediction module outputs the predicted diameter of the raindrop based on the force-time curve signal and uses the predicted diameter of the raindrop as the measurement result.

[0020] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0021] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A raindrop diameter measurement method, characterized in that: The following steps are involved: S1. Preparation of a superhydrophobic surface with a truncated cone array; S2, designing a raindrop diameter sensor by combining force sensor and super-hydrophobic surface; S3, training a raindrop diameter prediction model based on the Gaussian process regression algorithm; S4, deploying the raindrop diameter sensor at the point to be measured; S5, a raindrop diameter sensor collects the contact time and force between the raindrop and the super-hydrophobic surface; S6. Input the data collected by the raindrop diameter sensor into the raindrop diameter prediction model to obtain a raindrop diameter measurement result.

2. A raindrop diameter measurement method according to claim 1, characterized in that: S1 is specifically: S11, mixing PDMS prepolymer and cross-linking agent in a mass ratio of 8:1, stirring evenly and vacuuming for 30 minutes to remove bubbles; S12, fix the copper template with the truncated cone array square array structure on the spin coater suction cup, set the spin coating parameter to 600 r / s, and continue for 15 seconds to make the PDMS solution evenly distributed on the template surface; S13, after curing, the PDMS film was peeled off from the copper template, 0.4 g of titanium dioxide nanoparticles were mixed with 40 mL of anhydrous ethanol, the particles were evenly dispersed by ultrasonic treatment, and 400 μL of TMOS was added for surface modification; S14, fix the glass slide with the super-hydrophobic film on a spin coater, set the spin coating parameters to 1600 r / s, last for 45 seconds, and apply the nano-titanium dioxide solution; repeat 6-7 times; S15. Finally, the mixture was cured at 80°C for 2 hours to obtain a frustum-shaped square array super-hydrophobic surface.

3. A raindrop diameter measurement method according to claim 1, characterized in that: S3 specifically includes: constructing a model training feature set and using StandardScaler to standardize the input features; in the modeling process, the product of the RationalQuadratic kernel function and the constant kernel is selected as the kernel structure of the raindrop diameter prediction model. During the training process, 80% of the samples are used for fitting, and 20% of the samples are retained to verify the prediction ability.

4. A raindrop diameter measurement method according to claim 3, characterized in that: The specific steps of constructing the model training feature set are: collecting the force-time curve signal generated by raindrops hitting the super-hydrophobic surface, extracting the physical features, and obtaining the diameter of the water droplets by taking pictures with a high-speed camera, manually marking them, and establishing the model training feature set.

5. A raindrop diameter measuring device, characterized in that: The system includes a raindrop diameter sensor and a raindrop diameter prediction module. The raindrop diameter sensor consists of a force sensor and a super-hydrophobic surface with a truncated cone array. The raindrop diameter sensor is used to collect the force-time curve signal generated when the raindrop hits the super-hydrophobic surface. The raindrop diameter prediction module outputs the predicted diameter of the raindrop based on the force-time curve signal and uses the predicted diameter of the raindrop as the measurement result.

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