CN110849967A - Device and method for detecting frost on plant leaves using grating - Google Patents

Abstract

The invention discloses a device and method for detecting frost on plant leaves by using a grating. The device comprises a miniature vibration exciter, and a leaf frosting sheet, a light source, a scale grating and a light box are arranged below the micro vibration exciter, and a light box is fixed inside the light box. Condenser lens, indicating grating and light-receiving element, the light-receiving element is connected with the oscilloscope, and the outside of the whole device is a louver box. The invention adopts the transmission diffraction grating of the same specification, the dynamic and static combination of the double gratings, and superimposes the light beams passing through the two gratings into light beats with different frequencies according to the Doppler effect, which are detected by optical elements and counted by an oscilloscope. In different frosting stages, when the micro-vibrator and the blade frosting sheet resonate, the frost frequency is determined by the frequency with the largest number of light shots on the oscilloscope, and the change of frosting quality in different frosting stages is detected. The device of the invention has a simple structure, is non-contact and has high sensitivity, can more truly perceive the frost formation, and is convenient to detect the frost formation amount in different frost formation stages.

Description

Device and method for detecting frost on plant leaves using grating

technical field

The invention belongs to the field of agricultural meteorological disaster monitoring and control, and particularly relates to a device and method for detecting frost on plant leaves by using a grating.

Background technique

Plant frosting is part of the frosting of many objects. Since most of the current research on frost sensing is used in the field of refrigerator and air conditioner defrosting, although there are also fields such as agriculture and high-speed rail cable deicing and defrosting, the frosting products on the surface of plants are concerned. Few of them are directly or indirectly related to plants. Most of the products are frost sensors. Technically, electrical, optical, and thermal characteristics are used to judge the thickness and presence of frost. Accurately and objectively obtain a characterization of frosting phenomena.

US Patent (US201710671899.3) discloses a lidar sensor for frost detection, which is mainly used in vehicle systems, and the programming is complex and difficult to be widely used in natural environment frost detection; Chinese Patent (201120230963.2) discloses a plant leaf temperature sensor, Although it can detect the temperature of leaves to a certain extent, this sensor cannot effectively rely on temperature alone to determine frost formation; Chinese patent (201620196128.4) discloses a sensor for measuring the critical freezing temperature of plant leaves, which can measure the critical temperature of plant leaves. Freezing damage temperature, but it is still not suitable for the detection of frosting phenomenon; Chinese patent (201710797177.2) discloses a shielding structure for capacitive frosting detection, which detects the surface capacitance of the frosting plate and estimates the frosting state, but the sensor is vulnerable to the external environment The effect results in lower stability and sensitivity.

The sensor SF-110 developed by Apogee for agricultural frost protection is composed of two temperature sensors (precision thermistors) combined in one housing, which can provide the approximate temperature of leaves and leaf buds, but the surface temperature of leaves does not determine frost It is the only or necessary condition for formation, so it is difficult to predict frost on plant leaf surfaces and leaf buds.

The existing technology reflects the occurrence of temperature and frost phenomenon indirectly or directly to a certain extent, but since temperature is not a sufficient and necessary condition for frost formation, there are still many measured factors affecting frost formation, which can be considered not only from environmental conditions, but also It can be detected for the unique properties of the frost crystal itself.

SUMMARY OF THE INVENTION

Therefore, the present invention proposes a device and method for detecting frost formation by using a grating, which has the advantages of non-contact, simple structure and high sensitivity, and is easy to assemble and disassemble, and provides an idea for the research on frost formation detection in the field of agricultural meteorological disaster monitoring and control. .

The present invention is achieved through the following technical solutions:

A device for detecting frost on plant leaves by means of a grating comprises a column and a light box, the column is fixed with a micro-vibrator and a leaf frosting sheet that are in contact with each other from top to bottom; the lower part of the leaf frosting piece is provided with a light box, and the upper end of the light box A gap is processed near the frosting sheet of the blade, and the frosting sheet of the blade near the gap of the light box fixes the scale grating; a light source is arranged on one side of the light box, the light source and the transmission hole on the side of the light box, the condenser lens, The scale grating, the indicating grating and the center point of the light-receiving element are located on the same straight line; the light-receiving element is connected with the oscilloscope; the micro-exciter is signal-connected with the controller, and the controller is connected with the oscilloscope.

In the above technical solution, the shape of the leaf frosting sheet is similar to that of a plant leaf, and is made of glass fiber material with a thickness of 0.1-1 mm, and the surface of the leaf frosting sheet is coated with a coating similar to the thermodynamic coefficient of the real blade. .

In the above technical solution, a coverless cuboid-shaped louver box is also included, and the louver box encloses the micro exciter, the blade frosting sheet, the light source, the condenser lens, the scale grating, the indicating grating, the light receiving element and the light box.

In the above technical solution, the light source is a laser.

In the above technical solution, the light-receiving element may be a silicon photovoltaic cell or a silicon phototransistor.

In the above technical solution, the scale grating and the indicator grating use transmission diffraction gratings with the same specifications.

In the above technical solution, the micro vibration exciter is fixed on the upright column through a U-shaped card.

In the above technical solution, the scale grating is vertically fixed on the blade frosting sheet.

A method for detecting frost on plant leaves by using grating. When the blade frosting plate vibrates, it drives the scale grating to move, and a relative displacement occurs between the scale grating and the indicating grating. The laser passes through the scale grating and the indicating grating, and the beams of the two gratings are superimposed into Optical beats, which are detected by optical components and counted by an oscilloscope after signal conditioning; in different frosting stages, when the micro-vibrator resonates with the blade frosting sheet, the oscilloscope is used to determine the frequency with the largest number of light beats in this stage, Determine the frost frequency to detect the amount of frost in different frost stages.

Further, the frost frequency is the resonance frequency of the micro-vibrator and the blade frosting sheet.

The invention has the beneficial effects as follows: the invention adopts the form of dynamic and static combination of double gratings of the same specification, and superimposes the light beams passing through the two gratings into light beats with different frequency properties according to the Doppler effect, which is determined by the maximum light beat number displayed by the oscilloscope. The resonant frequency (that is, the frost frequency) of the blade frosting sheet in one cycle, and then the change of the frosting quality in different frosting stages is detected; compared with the current frosting sensor, it has the advantages of non-contact, simple structure and high sensitivity. A micro-vibrator is used to vibrate the frosting sheet of the blade, and the frequency input is controllable. The blade frosting sheet, which is made of glass fiber material and coated with a coating similar to the thermodynamic coefficient of the real blade, can sense the frost in time compared with the real blade, and is easy to detect the amount of frost.

Description of drawings

Fig. 1 is the device structure schematic diagram that utilizes grating to detect frost on plant leaves according to the present invention;

Fig. 2 is the exploded schematic diagram of the device of the present invention utilizing grating to detect frost on plant leaves;

FIG. 3 is a schematic diagram of the double grating detection frost frequency of the present invention.

Reference numerals: 1-miniature exciter, 2-holding piece, 3-U-shaped card, 4-column, 5-blade frosting plate, 6-light source, 7-condenser lens, 8-scale grating, 9-indication Grating, 10-light receiving element, 11-light box, 12-pillar, 13-oscilloscope, 14-wire, 15-louver box.

Detailed ways

The technical solutions of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

As shown in Figures 1 and 2, a device for detecting frost on plant leaves using a grating includes a micro exciter 1, a column 4, a leaf frosting sheet 5, a light source 6, a condenser 7, a scale grating 8, an indicator grating 9, Light receiving element 10 , light box 11 and oscilloscope 13 . The column 4 is fixed on the ground, the end of the blade frosting plate 5 is fixed on the upper end of the column 4, the micro vibration exciter 1 is fixed on the upper end of the column 4 through the U-shaped card 3, and the micro vibration exciter 1 is located on the blade frosting plate 5. The upper part, and the micro-vibrator 1 is in contact with the blade frosting sheet 5; the micro-vibrator 1 is connected with the signal of the controller, the controller is used to control the frequency of the micro-vibrator 1, and the controller is connected to the oscilloscope 13, and the micro-vibrator is connected to the oscilloscope 13. The vibration frequency of the device 1 is displayed on the oscilloscope 13 in real time. The shape of the leaf frosting sheet 5 is similar to that of a plant leaf, and is made of a glass fiber material with a thickness of 0.1-1 mm, and the surface of the blade frosting sheet 5 is coated with a coating similar to the thermodynamic coefficient of the real blade, which is used for Timely sense the presence of cream. The lower part of the blade frosting sheet 5 is provided with a light box 11, and the light box 11 is fixed on the ground by the pillar 12. The light box 11 is a hollow frame structure, and the upper end of the blade frosting sheet 5 is processed with a gap, and the blade frosting sheet 5 is close to The gap of the light box is vertically fixed and connected to the scale grating 8 through the clamping member 2 . One side of the light box 11 is provided with a light source 6, the light source 6 is fixed on the ground by a tripod, a side of the light box 11 opposite to the light source 6 is machined with a transmission hole, and the inside of the light box 11 is sequentially provided with a condenser lens 7 and an indicator grating from the side of the transmission hole. 9. The indicator grating 9 is movably linked on the bottom plate of the light box 11; the scale grating 8 fixed by the blade frosting sheet 5 is located between the condenser lens 7 and the indicator grating 9, and the light-receiving element 10 is fixed on the side plate opposite to the side of the transmission hole, and the light-receiving element 10 is connected to an oscilloscope 13 through a wire 14 . A device for detecting frost on plant leaves by means of a grating also includes a louver box 15 without a cover, the louver box 15 is a micro-exciter 1, a column 4, a leaf frosting sheet 5, a light source 6, a condenser lens 7, and a scale grating 8. , indicating grating 9, light receiving element 10, light box 11 and pillar 12 are enclosed in the interior, reducing the interference and influence of the external environment (such as wind speed, dust, light, etc.), and ensuring that the ambient temperature and humidity in the box are the same as the outside world.

In this embodiment, the light source 6 uses a laser; the light receiving element 10 may be a silicon photocell or a silicon phototransistor; the scale grating 8 and the indicator grating 9 both use transmission diffraction gratings and have the same specifications. The center points of the light source 6, the transmission hole, the condenser lens 7, the scale grating 8, the indicating grating 9, and the light receiving element 10 are located on the same straight line.

The device for detecting frost on plant leaves by using a grating is arranged in the tea garden, specifically: burying the uprights 4 and 12 in the soil of the tea garden, and the light source 6 is fixed on the ground through a tripod; are the same height, cover the louver box 15 outside. The controller controls the vibration of the micro-vibrator 1 and adjusts the output frequency of the micro-vibrator 1 so that the micro-vibrator 1 and the frosting sheet 5 of the blade resonate. Turn on the light source 6, the laser light passes through the transmission hole, the condenser lens 7, the scale grating 8 and the indicator grating 9 in sequence, and illuminates the light-receiving element 10; Be as parallel as possible without touching. As shown in Figure 3, when the blade frost 5 is forced to vibrate, it drives the scale grating 8 to move, and a relative displacement occurs between the scale grating 8 and the indicator grating 9. The laser passes through the scale grating 8 and the indicator grating 9. According to the Doppler effect The light beams passing through the two gratings are superimposed into light beats with different frequency properties. The light receiving element 10 receives the light beats and inputs them to the oscilloscope 13 for signal conditioning (amplification, shaping and filtering), and the number of light beats is displayed. When the micro-vibrator 1 resonates with the blade frosting sheet 5, the amplitude of the blade frosting sheet 5 is the largest, which is reflected as the maximum number of light beats. On the oscilloscope 13, find the frequency with the largest number of light beats in a cycle, that is, the resonance frequency of the micro-vibrator 1 and the blade frosting sheet 5, and the resonance frequency is the vibration frequency of the frost, referred to as the frost frequency. In different frosting stages (early, middle and late stages of frosting), the frequencies falling on the blade frosting sheet 5 are different. The natural frequency of the blade frosting sheet 5 in different frosting stages is monitored in real time and displayed by the oscilloscope 13 The maximum number of light beats determines the resonant frequency (ie, frost frequency) of the blade frosting sheet 5 in one cycle, and the frosting amount in different frosting stages can be calibrated and detected through the frost frequency.

For those skilled in the art, they can still modify the above-mentioned technical solutions, or perform equivalent replacements to some of the technical features. Any modifications, equivalent replacements made within the spirit and principles of the present invention, , improvements, etc. should all be included within the protection scope of the present invention.

Claims (10)

1. The utility model provides an utilize grating to detect plant leaf frosting which characterized in that: the device comprises a vertical column (4) and a light box (11), wherein the vertical column (4) is fixedly provided with a miniature vibration exciter (1) and a blade frosting sheet (5) which are in mutual contact from top to bottom; a light box (11) is arranged at the lower part of the blade frosting sheet (5), a gap is processed at the upper end of the light box (11) close to the blade frosting sheet (5), and a scale grating (8) is fixed on the blade frosting sheet (5) close to the gap of the light box; a light source (6) is arranged on one side of the light box (11), the light source (6) and a transmission hole on the side surface of the light box (11), and the central points of a condenser lens (7), a scale grating (8), an indication grating (9) and a light receiving element (10) which are sequentially arranged in the light box (11) are positioned on the same straight line; the light receiving element (10) is connected with an oscilloscope (13); the miniature vibration exciter (1) is in signal connection with a controller, and the controller is connected with an oscilloscope (13).

2. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1, wherein: the shape of the leaf frosting piece (5) is similar to that of a plant leaf, the leaf frosting piece is processed by adopting a glass fiber material with the thickness of 0.1-1mm, and the surface of the leaf frosting piece (5) is coated with a coating similar to the thermodynamic coefficient of a real leaf.

3. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1, wherein: the miniature vibration exciter further comprises a blind box (15) in an uncovered cuboid shape, wherein the blind box (15) surrounds the miniature vibration exciter (1), the blade frosting piece (5), the light source (6), the condenser lens (7), the scale grating (8), the indication grating (9), the light receiving element (10) and the light box (11) inside.

4. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1 or 3, wherein: the light source (6) adopts laser.

5. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1 or 3, wherein: the light receiving element (10) can be a silicon photocell or a silicon phototransistor.

6. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1 or 3, wherein: the scale grating (8) and the indication grating (9) adopt transmission type diffraction gratings with the same specification.

7. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1, wherein: the miniature vibration exciter (1) is fixed on the upright post (4) through a U-shaped clamp (3).

8. The device for detecting plant leaf frosting by using the optical grating as claimed in claim 1, wherein: the scale grating (8) is vertically fixed on the blade frosting sheet (5).

9. A method for detecting plant leaf frosting by using a grating is characterized in that: when the blade frosting sheet (5) vibrates, the scale grating (8) is driven to move, relative displacement is generated between the scale grating (8) and the indication grating (9), laser passes through the scale grating (8) and the indication grating (9), light beams of the two gratings are superposed to form a light beat, the light beat is detected by a light element (10), and the light beat after signal conditioning is counted by an oscilloscope (13); when the miniature vibration exciter (1) and the blade frosting sheet (5) resonate at different frosting stages, the frequency with the largest number of light beats at the stage is determined through the oscilloscope (13), and the frost frequency is determined, so that the frosting amount at different frosting stages is detected.

10. The method for detecting plant leaf frosting by using the optical grating as claimed in claim 9, wherein: the frost frequency is the resonance frequency of the miniature vibration exciter (1) and the blade frosting sheet (5).

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