CN107917723B - Small-particle-size seed flow sensing device in thin-surface laser - Google Patents
Small-particle-size seed flow sensing device in thin-surface laser Download PDFInfo
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- CN107917723B CN107917723B CN201711476301.1A CN201711476301A CN107917723B CN 107917723 B CN107917723 B CN 107917723B CN 201711476301 A CN201711476301 A CN 201711476301A CN 107917723 B CN107917723 B CN 107917723B
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- 206010070834 Sensitisation Diseases 0.000 claims description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/36—Forming the light into pulses
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
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Abstract
The invention belongs to the technical field of agricultural seed particle sensing detection, and particularly relates to a thin-surface laser small-particle-size seed flow sensing device. The sensing device includes: the seed feeding device comprises a seed inlet, a seed guide tube, a laser emitting module, a photoelectric receiver, a seed outlet, a signal acquisition system, a power supply unit and a packaging shell. The seed flow falling from the seed inlet of the seed metering device enters the detection area through the seed inlet, and a small part of light paths irradiating the thin-surface laser of the photoelectric receiver are shielded, so that the output voltage signal is disturbed, and the digitization of the seed flow is realized through the processing of the signal acquisition system. The sensing device provided by the invention has higher detection accuracy and excellent economical practicability, and can provide technical support for detecting the seed sowing performance (seed sowing amount, seed sowing frequency, miss-sowing, qualification index and the like) of the precise seed sowing device for seeds with medium and small particle diameters (such as rape, wheat, corn seeds and the like).
Description
Technical Field
The invention relates to the technical field of agricultural seed particle sensing detection, in particular to a thin-surface laser small-particle-size seed flow sensing device.
Background
The mechanized precision seeding can reduce labor intensity, improve operation efficiency and increase income of farmers, and is an important link of intelligent agricultural machinery development. In the sowing process, the sowing quality monitoring, the missing sowing detection, the sowing quantity monitoring and the sowing state diagram generation of the seed sowing device are trends of intelligent development of precision sowing, and the functions are realized by means of a seed flow sensing device which can accurately collect sowing information such as sowing frequency, sowing time interval, total sowing amount and the like in real time.
At present, the existing photoelectric detector for seed metering detection is mainly based on a photoelectric receiving and transmitting sensor which can detect large and medium grain diameter seeds such as corn, soybean, wheat and rice by separating light paths to realize the induction of the seeds so as to finish the detection of seed flow. However, for seed metering detection of seeds with small particle size and high seed metering frequency, detection omission is caused by a certain detection blind area, and the detection time resolution is low due to long time of a seed passing light path, so that two or more seeds with close intervals are difficult to distinguish, and finally accurate detection of the seed flow with small particle size is difficult to realize.
Disclosure of Invention
Therefore, the invention provides the small-grain-size seed flow sensing device in the thin-face laser, which can realize the non-blind area detection of the seed flow, improve the time resolution of the seed flow detection and solve the problem that two or more seeds cannot be detected due to the close spacing.
In order to solve the problems, the technical scheme provided by the invention is as follows:
the invention provides a thin-surface laser small and medium grain diameter seed flow sensing device which is in butt joint with a seed feeding port of a small and medium grain diameter seed sowing device, and the sensing device comprises: the seed guide tube, the laser emission module, the photoelectric receiver, the signal acquisition system and the power supply unit;
the seed guiding pipe comprises an upper seed guiding pipe and a lower seed guiding pipe which are coaxially arranged, and a light transmission gap exists between the upper end face of the lower seed guiding pipe and the lower end face of the upper seed guiding pipe;
the laser emission module and the photoelectric receiver are arranged at two sides of the seed guide tube corresponding to the light passing gap, the axis of the laser emission module is orthogonal to the center of the photoelectric receiver, and the photoelectric receiver is used for receiving the thin-surface laser formed at the light passing gap by the laser emission module;
the photoelectric receiver is electrically connected with the signal acquisition system, and the signal acquisition system and the laser emission module are electrically connected with the power supply unit;
the thin-surface laser has a preset thickness, the projection of the inner diameter of the lower pipe orifice of the upper seed guide pipe along the axial direction of the seed guide pipe is positioned in the thin-surface laser area capable of irradiating the photoelectric receiver, and the signal acquisition system is used for acquiring voltage signal disturbance generated by the change of the sensitization quantity of the photoelectric receiver caused by the seed flow passing through the thin-surface laser.
According to a preferred embodiment of the present invention, the laser emission module includes a laser emitter, a focusing lens and a straight wave mirror, where the laser emitter is used to emit point laser, and generates the thin laser with a light layer thickness of 0.5 mm-3 mm at the light passing gap after passing through the focusing lens and the straight wave mirror.
According to a preferred embodiment of the present invention, a diffusion angle of the thin-surface laser formed by the laser transmitter at the position of the light passing gap ranges from 10 ° to 160 °.
According to a preferred embodiment of the present invention, a light transmission gap of 0.5 mm-3 mm is provided between the upper end surface of the lower seed guide tube and the lower end surface of the upper seed guide tube.
According to a preferred embodiment of the present invention, the photo receiver is a silicon photocell, and the area where the maximum length of the photosensitive surface of the silicon photocell is located is taken as the light receiving area.
According to a preferred embodiment of the present invention, the distance between the laser transmitter and the surface of the silicon photocell is between 6mm and 60mm, and the light spot formed by the thin-surface laser on the surface of the silicon photocell at least covers the light receiving area.
According to a preferred embodiment of the present invention, the inner diameter of the lower nozzle of the upper seed guide tube is smaller than the maximum size that can be accommodated by the thin-surface laser light that can be irradiated to the light receiving area.
According to a preferred embodiment of the present invention, the inner diameter of the upper nozzle of the lower seed guide tube is smaller than or equal to the inner diameter of the lower nozzle of the lower seed guide tube, and the inner diameter of the upper nozzle of the lower seed guide tube is larger than the outer diameter of the lower nozzle of the upper seed guide tube.
According to a preferred embodiment of the invention, the sensing device further comprises: a seed inlet, a seed outlet and a packaging shell;
the seed inlet is formed by extending an upper pipe orifice of the upper seed guide pipe, and the seed outlet is formed by extending a lower pipe orifice of the lower seed guide pipe; the outer diameter of the seed inlet is matched and butted with the inner diameter of the seed throwing port; the packaging shell is used for protecting the internal structure and packaging the internal structure into a whole.
According to a preferred embodiment of the present invention, the signal acquisition system circuit includes a primary amplifying circuit, a secondary amplifying circuit, a half-wave rectifying circuit, a voltage comparing circuit, and a monostable trigger circuit;
the first-stage amplifying circuit and the second-stage amplifying circuit are built by an AD620 chip and are used for amplifying photoelectric signals generated after seeds shield part of light paths, and the adjusting range of the amplification factor of each stage is 10-200 times;
the half-wave rectification circuit chops the negative voltage signal output by the secondary amplification circuit by utilizing the unidirectional conduction effect of the diode;
the voltage comparison circuit comprises an LM393 chip and a variable resistor, wherein the variable resistor is used for adjusting a comparison voltage threshold value and converting an output signal of the half-wave rectification circuit into a regular square wave with a certain pulse width, and the pulse width is changed along with the change of the comparison voltage threshold value;
the monostable trigger circuit comprises a 74LS123 chip, a capacitor and a resistor, different capacitors and resistors are selected to change the delay time, output signals of the comparator are integrated into regular pulse signals, and accordingly single seed corresponding output of single pulse is achieved, namely a seed flow sequence corresponding pulse sequence is achieved, and finally digitization of seed flow is achieved.
The beneficial effects of the invention are as follows: compared with the existing photoelectric detection device, the thin-surface laser medium-small particle size seed flow sensing device has the advantages that point-shaped light of the laser transmitter is processed through the focusing lens and the straight wave mirror, and then the formed thin-surface laser generated by the diffusion of the linear light source irradiates the surface of the silicon photocell to form rectangular light spots, the light spot width is only 1mm, the time for the seeds to pass through the thin-surface laser is enough small, the seeds can be accurately detected when the interval between the seeds is larger than 1mm, and the detection time resolution is improved. The problems that in the traditional photoelectric detection, an infrared diode light source is adopted, the time for seeds to pass through a detection light area is long, and when two or more seeds enter the light area at the same time, the seeds cannot be distinguished, so that false detection is caused are solved; the design not only has the advantage of non-contact detection, but also obtains the inner diameter of the seed guide tube, the specific position relation of the seed guide tube relative to the thin-surface laser pair and the relative position of the laser emitter and the silicon photocell through strict geometric model calculation, thereby eliminating the detection blind area. The device can realize that single seeds correspondingly output single pulse, namely, realize that the seed flow sequence corresponds to the pulse sequence, and finally realize the digitization of the seed flow. The device has the advantages of low cost of the used components, small structure and convenient installation. The device can accurately detect the seeds with the large and medium particle diameters smaller than 10 mm.
Drawings
In order to more clearly illustrate the embodiments or the technical solutions in the prior art, the following description will briefly introduce the drawings that are needed in the embodiments or the description of the prior art, it is obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a thin-surface laser small-particle-size seed flow sensing device;
FIG. 2a is a projection view of laser emission and reception according to an embodiment of the present invention;
fig. 2b is a schematic perspective view of laser emission and reception according to an embodiment of the present invention;
FIG. 3 is a block diagram of a signal acquisition system according to an embodiment of the present invention;
Detailed Description
The following description of the embodiments refers to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. The directional terms mentioned in the present invention, such as [ upper ], [ lower ], [ front ], [ rear ], [ left ], [ right ], [ inner ], [ outer ], [ side ], etc., are only referring to the directions of the attached drawings. Accordingly, directional terminology is used to describe and understand the invention and is not limiting of the invention. In the drawings, like elements are designated by like reference numerals.
The invention aims at solving the technical problems of missed detection caused by a certain detection blind area and low detection time resolution caused by long light passing time when the existing photoelectric detection device is applied to the sensing detection of seed flow with small and medium particle size discharge.
The following describes in detail the thin-face laser small-particle-size seed flow sensing device provided by the embodiment of the invention with reference to the accompanying drawings.
As shown in fig. 1, the structure of the sensing device for small and medium grain size seed flow in thin laser provided by the invention is schematically shown, the sensing device is in butt joint with a seed feeding port of a small and medium grain size seed metering device, and the sensing device comprises: the seed feeding device comprises a seed inlet 1, a seed guide tube, a laser emitting module 3, a photoelectric receiver 4, a seed outlet 7, a bracket 8, a signal acquisition system 10 and a power supply unit 11.
The outer diameter of the seed inlet 1 is matched with the inner diameter of the seed feeding port of the seed metering device, so that the sensing device is connected to the seed metering device, and anti-skid threads are arranged on the outer wall of the seed inlet 1, so that the phenomenon of falling off after installation is avoided. The seed guiding pipe comprises an upper seed guiding pipe 2 and a lower seed guiding pipe 6, and the upper seed guiding pipe 2 and the lower seed guiding pipe 6 are coaxially arranged; the upper pipe orifice of the upper seed guide pipe 2 is extended to form the seed inlet 1, and the lower pipe orifice of the lower seed guide pipe is extended to form the seed outlet 7. The length of the upper seed guide tube 2 may be 20mm to 40mm, and the length of the lower seed guide tube 6 may be 20mm to 40mm. A light passing gap exists between the upper end face of the lower seed guide tube 6 and the lower end face of the upper seed guide tube 2. The inner diameter of the upper pipe orifice of the lower seed guiding pipe 6 is larger than the outer diameter of the lower pipe orifice of the upper seed guiding pipe 2, so that falling seeds are ensured to smoothly enter the lower seed guiding pipe 6; the inner diameter of the upper pipe orifice of the lower seed guide pipe 6 is smaller than or equal to the inner diameter of the lower pipe orifice of the lower seed guide pipe; preferably, the inner diameter of the lower pipe orifice of the lower seed guiding pipe 6 is larger than that of the upper pipe orifice, and the inner diameter of the lower pipe orifice is in a tapered shape which is contracted from bottom to top, so that the possibility of repeated detection caused by collision after seeds fall is prevented.
The laser emission module 3 and the photoelectric receiver 4 are arranged on two sides of the seed guide tube corresponding to the light passing gap, the axis of the laser emission module 3 is orthogonal to the center of the photoelectric receiver 4, the photoelectric receiver 4 is used for receiving the thin-surface laser 5 formed by the laser emission module 3 at the light passing gap, and the thickness of the thin-surface laser 5 is 0.5 mm-3 mm, preferably 1mm. The projection 501 of the inner diameter of the lower pipe orifice of the upper seed guide pipe 2 along the axial direction of the seed guide pipe is positioned in the area of the thin-surface laser 5 capable of irradiating the photoelectric receiver 4, the distance between the lower seed guide pipe 6 and the upper seed guide pipe 2 is 0.5 mm-3 mm, and preferably, the width of the light-passing gap is 0.8 mm-2.5 mm. It is also preferable that the inner diameter of the upper nozzle of the upper seed guide tube 2 is larger than that of the lower nozzle, and the projection 501 is in the area of the thin-surface laser 5, so as to avoid detection blind areas. The cross section of the seed guide tube is round, elliptic, rectangular or other polygonal.
The bracket 8 is used for carrying the signal acquisition system 10, and the bracket 8 comprises a positioning column 12 for fixing the signal acquisition system 10; the signal acquisition system 10 comprises an NRF transceiver module 9 for outputting detected seed stream data; the power supply unit 11 is used for supplying power to the device, the photoelectric receiver 4 is electrically connected with the signal acquisition system 10, and the signal acquisition system 10 and the laser emission module 3 are electrically connected with the power supply unit 11. The signal acquisition system 10 is used for acquiring voltage signal disturbance generated by the change of the light sensing quantity of the photoelectric receiver 4 caused by the seed flow passing through the thin-surface laser 5; the signal acquisition system 10 and the power supply unit 11 are arranged on the right side of the seed guide tube. The sensing device further includes: a seed discharge state indicator lamp 13 for indicating a seed discharge state of the seed stream; a power switch 14 for turning on/off the sensing device; the power indicator 15 is used for indicating the power supply state. The sensing device further comprises an encapsulation shell, wherein the encapsulation shell is used for protecting the internal structures and encapsulating the internal structures into a whole. The seed metering status indicator lamp 13, the power switch 14, and the power indicator lamp 15 are disposed at preset positions of the package according to actual conditions, which is not limited herein.
As shown in fig. 2a, for the laser transmitting and receiving projection diagram provided in the embodiment of the present invention, the laser transmitting module 3 sequentially includes a laser transmitter 301, a focusing lens 302, and a linear wave mirror 303 along the light path transmitting direction; the photoelectric receiver can be selected as a silicon photocell 4, the silicon photocell 4 is 10mm×10mm in this embodiment, and the light receiving surface of the silicon photocell 4 is arranged facing the laser emitting module 3; the laser transmitter 301 is coaxially arranged with the focusing lens 302 and the in-line wave mirror 303, and the central axis is orthogonal to the center of the silicon photocell 4. The point light source emitted by the laser emitter 301 sequentially passes through the focusing lens 302 and the in-line wave mirror 303 to form a thin-surface laser 5 with a certain diffusion angle and dense light paths, the diffusion angle of the thin-surface laser 5 is between 10 ° and 160 °, preferably 30 °, and the light area formed by the thin-surface laser 5 is a trapezoid area.
As shown in fig. 2b, which is a schematic perspective view of laser emission and receiving provided in the embodiment of the present invention, the thickness of the optical layer formed by the thin-surface laser 5 is 0.5 mm-3 mm, preferably 1mm. The inner diameter of the lower pipe orifice of the upper seed guide pipe 2 is smaller than or equal to the maximum circular diameter which can be accommodated by the light zone formed by the thin-surface laser 5, that is to say, the projection of the inner diameter of the lower pipe orifice of the upper seed guide pipe 2 along the axial direction of the seed guide pipe is positioned in the area of the thin-surface laser 5. In order to increase the length of the light receiving surface of the silicon photocell 4 and further increase the inner diameter of the lower pipe orifice of the upper seed guide pipe 2, the silicon photocell 4 is placed by rotating a certain angle, preferably 45 degrees with the light layer formed by the thin-surface laser 5, and the area where the diagonal line of the light receiving surface of the silicon photocell 4 is located is taken as a light receiving area, and the distance between the laser emitter 301 and the surface of the silicon photocell 4 is between 6mm and 60mm, preferably 23mm. After being processed by the focusing lens 302 and the in-line wave mirror 303, the spot light of the laser emitter 301 irradiates the surface of the silicon photocell 4 to form a rectangular light spot, the width of the light spot is very small, the width is between 0.5mm and 3mm, preferably 1mm, and the projection of the light spot on the silicon photocell 4 is positioned in the range of the light receiving area, so that the seeds 16 passing through the thin-surface laser 5 are all sensed.
The geometrical operation shows that when the distance between the laser transmitter 301 and the light receiving surface of the silicon photocell 4 is 23mm, the length of the light spot irradiated on the surface of the silicon photocell 4 is 14.1mm, and the area where the diagonal line of the silicon photocell 4 is located is exactly covered; the diameter of the largest circle which can be accommodated by the trapezoid optical area is 11.1mm, so that the diameter of the seed falling pipe diameter is required to be smaller than 11.1mm, and the inner diameter of the lower pipe orifice of the upper seed guide pipe 2 is preferably 10mm, so that a blind area possibly generated by detection is eliminated. When the thickness of the optical layer is only 1mm, the time for passing the medium and small-grain seeds 16 through the optical area is small enough, the distance between the two seeds can be detected as long as the distance is larger than 1mm, and the situation that the distance between the seeds is smaller than 1mm rarely occurs in the actual agricultural sowing process, so that the time resolution of seed detection is improved, and the accurate detection of the medium and small-grain seeds is realized. In order to increase the time for using the device of the present invention after one charge, the laser emitter 301 uses a laser emitter with a minimum power consumption of only 5mW as a light source.
As shown in fig. 3, the present invention further includes a signal acquisition system circuit integrated on the signal acquisition system. The signal acquisition system circuit comprises a primary amplifying circuit 200, a secondary amplifying circuit 300, a half-wave rectifying circuit 400, a voltage comparison circuit 500 and a monostable trigger circuit 600. The primary amplifying circuit 200 and the secondary amplifying circuit 300 are built by AD620 chips and are used for amplifying photoelectric signals generated after the seed flow shields part of the light path, and the adjusting range of the amplification factor of each stage is 10-200 times, preferably 30-100 times; the half-wave rectification circuit 400 chops the negative voltage signal output by the secondary amplification circuit 300 by utilizing the unidirectional conduction effect of a diode; the voltage comparison circuit 500 comprises an LM393 chip and a variable resistor, wherein the variable resistor is used for adjusting a comparison voltage threshold value, and converting the output signal of the half-wave rectification circuit 400 into a regular square wave with a certain pulse width, and the pulse width is changed along with the change of the comparison voltage threshold value; the monostable trigger circuit 600 includes a 74LS123 chip, a capacitor, and a resistor, where different capacitors and resistors are selected to change the delay time, and the delay time is preferably 1ms, and the output signals of the comparators are integrated into a regular pulse signal. And forming a pulse sequence 700 of the seed stream, realizing that a single seed correspondingly outputs a single pulse, namely realizing that the seed stream sequence corresponds to the pulse sequence, and finally realizing the digitization of the seed stream. In another embodiment, the primary amplifying circuit 200 and the secondary amplifying circuit 300 may be replaced by a single-stage amplifying circuit.
Compared with the existing photoelectric detection device, the thin-surface laser medium-small particle size seed flow sensing device provided by the invention has the advantages that after the point-shaped light of the laser transmitter is processed through the focusing lens and the straight wave mirror, the formed thin-surface laser generated by the diffused linear light source irradiates the surface of the silicon photocell to form rectangular light spots, the light spot width is only 1mm, the time for the seeds to pass through the light area is enough small, the seeds can be accurately detected when the interval between the seeds is larger than 1mm, and the detection time resolution is improved. The problem of false detection caused by the fact that two or more seeds cannot be distinguished when entering the light zone at the same time due to the fact that the time for the seeds to pass through the light zone is long in the conventional infrared diode light source commonly used in photoelectric detection is solved; the design has the advantage of non-contact detection, and the size of the inner diameter of the seed guide tube, the specific position relation relative to the thin-surface laser and the relative position of the laser emitter and the silicon photocell are obtained through strict geometric model calculation, so that the detection blind area is eliminated. The device has the advantages of low cost of the used components, small structure and convenient installation. The device can accurately detect the seeds with the large and medium particle diameters smaller than 10 mm.
In summary, although the present invention has been described in terms of the preferred embodiments, the preferred embodiments are not limited to the above embodiments, and various modifications and changes can be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is defined by the appended claims.
Claims (9)
1. A thin-face laser small-grain-diameter seed flow sensing device which is in butt joint with a seed feeding port of a small-grain-diameter seed metering device, and is characterized by comprising: the seed guide tube, the laser emission module, the photoelectric receiver, the signal acquisition system and the power supply unit;
the seed guiding pipe comprises an upper seed guiding pipe and a lower seed guiding pipe which are coaxially arranged, and a light transmission gap exists between the upper end face of the lower seed guiding pipe and the lower end face of the upper seed guiding pipe;
the laser emission module and the photoelectric receiver are arranged at two sides of the seed guide tube corresponding to the light passing gap, the axis of the laser emission module is orthogonal to the center of the photoelectric receiver, and the photoelectric receiver is used for receiving the thin-surface laser formed at the light passing gap by the laser emission module;
the laser emission module comprises a laser emitter, a focusing lens and a straight wave mirror, wherein the laser emitter is used for emitting point laser and generating the thin laser with the thickness of a light layer of 0.5-3 mm at the light passing gap through the focusing lens and the straight wave mirror;
the photoelectric receiver is electrically connected with the signal acquisition system, and the signal acquisition system and the laser emission module are electrically connected with the power supply unit;
wherein the thin-surface laser has a preset thickness, the projection of the inner diameter of the lower pipe orifice of the upper seed guide pipe along the axial direction of the seed guide pipe is positioned in the thin-surface laser area capable of irradiating the photoelectric receiver, the signal acquisition system is used for acquiring voltage signal disturbance generated by the change of the sensitization quantity of the photoelectric receiver caused by the seed flow passing through the thin-surface laser; the signal acquisition system is also used for generating pulse sequence signals corresponding to the seed flow sequences, so that single seeds correspondingly output single pulses; the signal acquisition system is also used for generating a pulse sequence signal corresponding to the seed stream sequence; realizing the corresponding output of a single pulse by a single seed.
2. The sensing device of claim 1, wherein a spread angle of the thin-sided laser light formed by the laser transmitter at the position of the light passing gap is in a range of 10 ° to 160 °.
3. The sensing device according to claim 1, wherein a light passing gap of 0.5mm to 3mm is provided between the upper end face of the lower seed guide tube and the lower end face of the upper seed guide tube.
4. The sensor of claim 1, wherein the photo receiver is a silicon photocell, and the area where the maximum length of the photosensitive surface of the silicon photocell is located is the light receiving area.
5. The sensing device of claim 4, wherein the laser transmitter is spaced from the surface of the silicon photocell by a distance of between 6mm and 60mm, and the spot of the thin-surface laser light formed on the surface of the silicon photocell covers at least the light receiving area.
6. The sensor apparatus of claim 5, wherein the lower orifice inner diameter of the upper seed guide tube is smaller than the maximum size that can be accommodated by the thin-surface laser light that can be irradiated to the light receiving area.
7. The sensing device of claim 1, wherein an upper nozzle inner diameter of the lower seed guide tube is less than or equal to a lower nozzle inner diameter of the lower seed guide tube, the upper nozzle inner diameter of the lower seed guide tube being greater than the lower nozzle outer diameter of the upper seed guide tube.
8. The sensing device of claim 1, further comprising: a seed inlet, a seed outlet and a packaging shell;
the seed inlet is formed by extending an upper pipe orifice of the upper seed guide pipe, and the seed outlet is formed by extending a lower pipe orifice of the lower seed guide pipe; the outer diameter of the seed inlet is matched and butted with the inner diameter of the seed throwing port; the packaging shell is used for protecting the internal structure and packaging the internal structure into a whole.
9. The sensing device of claim 1, wherein the signal acquisition system comprises a primary amplification circuit, a secondary amplification circuit, a half-wave rectification circuit, a voltage comparison circuit, a monostable trigger circuit;
the first-stage amplifying circuit and the second-stage amplifying circuit are built by an AD620 chip and are used for amplifying photoelectric signals generated after seeds shield part of light paths, and the adjusting range of the amplification factor of each stage is 10-200 times;
the half-wave rectification circuit chops the negative voltage signal output by the secondary amplification circuit by utilizing the unidirectional conduction effect of the diode;
the voltage comparison circuit comprises an LM393 chip and a variable resistor, wherein the variable resistor is used for adjusting a comparison voltage threshold value and converting an output signal of the half-wave rectification circuit into a regular square wave with a certain pulse width, and the pulse width is changed along with the change of the comparison voltage threshold value;
the monostable trigger circuit comprises a 74LS123 chip, a capacitor and a resistor, wherein different capacitors and resistors are selected to change the delay time, and the output signals of the comparator are integrated into pulse sequence signals corresponding to the seed stream sequence; realizing the corresponding output of a single pulse by a single seed.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711476301.1A CN107917723B (en) | 2017-12-29 | 2017-12-29 | Small-particle-size seed flow sensing device in thin-surface laser |
Applications Claiming Priority (1)
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| CN108918904B (en) * | 2018-07-13 | 2019-11-12 | 华中农业大学 | A kind of middle small particle seed precision drilling monitoring device and method |
| CN110595553B (en) * | 2019-09-18 | 2020-11-24 | 华中农业大学 | LED visible light surface large and medium seed crop seed metering detection device |
| CN110646019B (en) * | 2019-09-18 | 2021-11-30 | 华中农业大学 | Seed crop seed metering detection device |
| CN110558007B (en) * | 2019-10-12 | 2020-12-18 | 华中农业大学 | Small-particle-size seed particle flow counting sensing device suitable for high-frequency seed metering |
| CN110889486B (en) * | 2019-11-07 | 2023-10-20 | 北京农业智能装备技术研究中心 | Insect occurrence situation acquisition system and method |
| CN112881340A (en) * | 2021-01-12 | 2021-06-01 | 华中农业大学 | General sensing device of refraction type thin-surface laser seed flow |
| CN113039901A (en) * | 2021-03-30 | 2021-06-29 | 华中农业大学 | Digital seed sowing device based on seed sowing frequency feedback and seed sowing control method |
| CN113390466A (en) * | 2021-07-02 | 2021-09-14 | 华中农业大学 | Method for collecting seeding quality information of seeds with medium and small particle diameters and monitoring operation state of machine tool |
| CN114128444B (en) * | 2021-11-26 | 2023-08-22 | 中国农业大学 | Precise seeding parameter wireless remote monitoring method and device based on laser sensing |
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