Rape seed metering detection device and method based on microwave dynamic balance field

Abstract

The invention provides an oilseed rape seed metering detection device and method based on a microwave dynamic balance field, the detection device comprises a photoelectric detection device and a microwave detection device, the microwave detection device comprises a metal aluminum box, a J-shaped polyurethane foam wave-absorbing material is arranged on the inner wall of the metal aluminum box, and a microwave radar module is further installed in the metal aluminum box; the microwave radar module comprises a TX transmitting antenna, an RX receiving antenna, a frequency mixer and a synthesizer. According to the invention, the purpose of detecting rape seeds is achieved by forming a microwave dynamic balance field, simultaneous detection of multiple seeds can be carried out aiming at the inevitable overlapping phenomenon of the seeds during high-frequency seed metering, high precision can still be maintained when the multiple seeds pass through a detection area at the same time, and the phenomenon of missing detection caused by shielding is avoided; a photoelectric detection device is arranged as a microwave dynamic balance field triggering device, a microwave dynamic balance field is reasonably opened and closed, the problem of device overheating caused by long-time opening of the microwave field is solved, detection power consumption is reduced, and the service life of the device is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision seeding detection, and in particular relates to a rapeseed seeding detection device and method based on a microwave dynamic balance field. Background Art

[0002] In the process of rapeseed sowing and production, the accuracy and real-time performance of seed detection are crucial to improving work efficiency and crop yield. However, rapeseed seeds are small in size, low in density, and their color is similar to the background environment such as soil, making seed detection a complex technical problem. Traditional photoelectric detection devices rely on light sources to count seeds, which are easily affected by changes in ambient light and interference from impurities. In addition, photoelectric detection is easily affected by seed position deviation during operation. When seeds are blocked by debris or in an overlapping state, the detection efficiency of the photoelectric detection device will be significantly reduced, resulting in high false alarm rate and low detection accuracy. In addition, during the photoelectric detection process, when rapeseed seeds fall through the detection area at high speed, if multiple seeds overlap, the photoelectric detection device can usually only detect the outermost seeds, and the blocked seeds will be missed, resulting in inaccurate high-frequency seed counting. In order to solve the above technical problems, the present invention designs a rapeseed seed detection device and method based on a microwave dynamic equilibrium field. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a rapeseed seeding detection device and method based on a microwave dynamic balance field, which can solve the problem of missed detection caused by overlapping of small-size seeds such as rapeseed under high-frequency conditions, and effectively improve the detection accuracy of high-frequency seeding.

[0004] The present invention achieves the above technical objectives through the following technical means.

[0005] A rape seeding detection device based on microwave dynamic balance field, comprising a photoelectric detection device and a microwave detection device arranged below the seeding port of a pneumatic seeding device and connected by a seeding pipeline, the two are connected in series and powered by a power supply, and a switch is located between the power lines of the two;

[0006] The photoelectric detection device includes a laser emission module, a Fresnel collimating lens, a Fresnel focusing lens, and an infrared photosensitive transistor; the laser emission module emits a straight-line infrared laser, which is collimated by the Fresnel collimating lens to form a laser film surface, and the laser film surface is focused on the infrared photosensitive transistor by the Fresnel focusing lens;

[0007] The microwave detection device includes a metal aluminum box, in which a microwave radar module is installed. The signal line of the microwave radar module is connected to a signal processor, a single-chip computer module, a host computer, and an oscilloscope. Except for the inner wall on the side facing the microwave radar module, the other inner walls of the metal aluminum box are arranged with J-shaped polyurethane foam absorbing material; the microwave radar module includes a TX transmitting antenna, an RX receiving antenna, a mixer, and a synthesizer. The synthesizer generates a linear frequency modulation pulse, which is transmitted by the TX transmitting antenna to the metal aluminum box, and the RX receiving antenna receives the linear frequency modulation pulse reflected by the metal aluminum box. The mixer mixes and modulates the RX signal and the TX signal to form an intermediate frequency signal.

[0008] The rapeseed seeding detection method based on microwave dynamic balance field using the above-mentioned rapeseed seeding detection device based on microwave dynamic balance field includes the following process:

[0009] Step 1: Install the entire set of detection devices below the seeding port of the pneumatic seed meter, connected by a seeding pipe, and the photoelectric detection device is located above the detection area of ​​the microwave radar module;

[0010] Step 2: The seed metering device plants seeds. When the rapeseed seeds pass through the photoelectric detection area, they block the infrared light emitted by the laser emission module, causing the current generated by the infrared photosensitive transistor to decrease. The photoelectric detection device sends a high-level seed trigger signal according to the current change. After receiving the seed trigger signal, the single-chip microcomputer module outputs a switch signal to the switch that controls the power supply of the microwave radar module, and the microwave radar module is turned on.

[0011] Step 3: The synthesizer generates a linear frequency modulation pulse signal, which is transmitted by the TX transmitting antenna. The transmitted linear frequency modulation pulse signal propagates in the metal aluminum box, and is reflected back after being incident on the surface of the aluminum alloy profile facing the microwave radar module. The signals in other directions are absorbed by the J-shaped polyurethane foam absorbing material to form a microwave dynamic balance field with a fixed frequency and amplitude. The reflected linear frequency modulation pulse is reabsorbed and captured by the RX receiving antenna, and then the transmitted linear frequency modulation pulse signal and the received linear frequency modulation pulse signal are combined by the mixer to generate an intermediate frequency signal. The intermediate frequency signal emitted by the microwave radar module is displayed in the oscilloscope, and continuous acquisition is performed through the oscilloscope to obtain the time domain diagram of the microwave dynamic balance field.

[0012] Step 4: When the rapeseed seeds continue to fall and enter the detection area of ​​the microwave detection device, the microwave dynamic balance field is destroyed, the intermediate frequency signal changes, and the changed signal is amplified and filtered by the improved signal amplification circuit and filtering and step-down circuit in the signal processor;

[0013] Step 5: Send the intermediate frequency signal after amplification, filtering and voltage reduction to the signal comparison circuit in the signal processor for comparison, and judge whether there are seeds entering the detection area according to the comparison result. The comparison circuit sends the comparison result pulse to the single-chip microcomputer module, and the single-chip microcomputer module obtains the rapeseed seed number information after processing, and sends it to the host computer through the serial port;

[0014] Step 6: When the photoelectric detection device does not detect rapeseed seeds for a long time, a low-level signal is output to the single-chip microcomputer module, and the single-chip microcomputer module cuts off the power supply of the microwave radar module, closes the microwave dynamic balance field, and waits for the next infrared photoelectric trigger signal;

[0015] Step 7: Based on the oscilloscope waveform, adjust the amplifier circuit amplification factor, comparison circuit threshold, microcontroller module sampling frequency, and replay missed time threshold.

[0016] Furthermore, in step 4, the signal amplification circuit adopts a two-stage amplification circuit, wherein the first-stage amplification chip is AD620ARZ-REEL, and the second-stage amplification circuit is AD8421ARMZ-R7 with a higher bandwidth, and the second-stage amplification circuit can amplify the voltage by more than one hundred thousand times; the amplification method of the second-stage signal amplification circuit is: the 1 pin (RG pin) of the first-stage amplification chip U4 is connected to one end of the sliding resistor R14, and the other end of the sliding resistor R14 is connected to the 8 pin of the second-stage amplification chip U4, which is used to adjust the voltage bias of the first-stage amplification circuit signal; the 2 pin (-IN pin) and the 3 pin (+IN pin) are respectively connected to the nodes of the resistors R15 and R16, which are the signal input pins of the first-stage amplification circuit, wherein the positive input or the negative input can be selected by wiring the H4 pin with an external wiring cap. Input; Pin 4 (-VS pin) is connected to negative power supply AVEE_5V, and is grounded through capacitors C15 and C16 to stabilize the voltage; Pin 5 (REF pin) is connected to resistor R18, and the other end of resistor R18 is connected to sliding rheostat R19, and the two ends of the sliding rheostat are respectively connected to positive power supply AVCC_5V and negative power supply AVEE_5V, which are used to adjust the amplification factor of the first-stage amplifier circuit signal, and the amplification factor is 1 to 10000. At the same time, Pin 5 is also connected to AGND through resistor R17; Pin 6 is connected to pin H3 through R20 to output the first-stage amplification signal and is connected to Pin 4 (+IN pin) of the second-stage amplifier circuit chip; Pin 7 (+VS pin) is connected to positive power supply AVCC_5V, and is grounded through capacitors C17 and C18 to stabilize the voltage;

[0017] Pin 1 of the secondary amplifier chip U12 is grounded through resistor R21, indicating that the secondary amplifier input signal is a positive input; pins 2 and 3 are both RG pins, which are connected together through a sliding rheostat R28. Adjusting the sliding rheostat can adjust the voltage bias of the secondary amplifier signal; pin 4 (+IN pin) is connected to the output pin (OUTPUT pin) of the primary amplifier chip; pin 5 (-VS pin) is connected to the negative power supply AVEE_5V, and is grounded through capacitors C39 and C40 to stabilize the voltage; pin 6 (REF pin) is connected to resistor R11, and the voltage The other end of resistor R11 is connected to sliding rheostat R12, and the two ends of the sliding rheostat are respectively connected to the positive power supply AVCC_5V and the negative power supply AVEE_5V, which are used to adjust the amplification factor of the secondary amplifier circuit signal. The amplification factor is also 1 to 10000. At the same time, pin 5 is also connected to AGND through resistor R10; pin 7 (VOUTPUT pin) is connected to R13 and output pin P6 for the final amplified signal output; pin 8 (+VS pin) is connected to the positive power supply AVCC_5V, and is grounded through capacitors C22 and C21 to stabilize the voltage.

[0018] Furthermore, in step 4, the working method of the filtering and step-down circuit is as follows: the P1 and P2 terminals are the input and output ports of the signal and the ground wire, and the high-frequency spike intermediate frequency signal is filtered into a low-frequency voltage signal through 6 2.2uf capacitors C1~C6 in parallel, so that the signal is easier to collect and compare, and then the voltage is reduced by parallel voltage division through resistors R1 (3.3KΩ) and R2 (1.6KΩ) to prevent the signal voltage value from being higher than the comparator threshold.

[0019] Further, in step 5, when the voltage value of the intermediate frequency signal after processing in step 4 does not exceed the first predetermined threshold value of the signal comparison circuit, the comparison circuit does not react; when it exceeds the first predetermined threshold value, the current detection state is in single-particle detection, and the comparison circuit outputs 1 square wave pulse; when it exceeds the second predetermined threshold value, the current detection state is in multiple-particle detection, and the comparison circuit outputs a square wave pulse number plus 1; when it exceeds the third predetermined threshold value, the current detection state is in multiple-particle detection, and the comparison circuit outputs a square wave pulse number that continues to increase by 1; wherein the third predetermined threshold value is greater than the second predetermined threshold value, and the second predetermined threshold value is greater than the first predetermined threshold value.

[0020] Furthermore, in step 5, the working method of the comparison circuit (unipolar) is as follows: the operational amplifier U1 (ADA4665) is used for signal amplification, and its 3rd pin (+IN) is connected to the 2nd pin of the H1 interface, the 3rd pin of H1 is connected to the power supply and the ground through the sliding rheostat R4, the 1st pin of H1 is connected to the 4th pin of U1 and grounded together, and after the 2nd and 3rd pins of H1 are connected through the short-circuit cap, the comparison threshold can be adjusted by adjusting the resistance value of the sliding rheostat R4, and the threshold can also be controlled by software by connecting the 1st and 2nd pins of U1; the 2nd pin of U1 (- The comparison circuit P9 (TLV3501AIDR) is used for signal comparison processing, and its 3-pin (+IN) is connected to the output signal of the operational amplifier U1 for comparing the input signal level; the 2-pin (-IN) is connected to R30 for stabilizing the circuit gain, and is connected to GND through a 1MΩ resistor R5 as a reference level; the 5-pin (V-) is grounded, and the 8-pin (V+) is connected to the VCC power supply. The comparison circuit output (7-pin) is connected to the interface P10 through R29 (50Ω) to provide the final comparison signal output; the resistors R6 (1kΩ) and R4 (10kΩ) form a voltage divider circuit to reduce the VCC voltage to a suitable input signal level; C41, C42, C43 and C45 are 10μF and 100nF capacitors respectively, which are used for VCC power supply decoupling to ensure power supply stability and avoid high-frequency noise interference.

[0021] Furthermore, in step 5, the single-chip microcomputer module includes a single-chip microcomputer main control board, an LCD display screen and a communication module, and has the functions of pulse signal reception, counting, information display and transmission; when the single-chip microcomputer module receives an external pulse signal, it counts the pulse signal and updates the counting information in real time through a built-in algorithm; the updated counting information is displayed on the LCD screen at the same time, and the counting information is transmitted to the host computer through the serial port communication module; in addition to completing the pulse counting function, the single-chip microcomputer module is also responsible for interacting with the host computer; after receiving the counting information, the host computer stores the data in real time.

[0022] Furthermore, step 7 includes: observing the waveform of the oscilloscope when the rapeseed seeds fall, adjusting the resistance of the sliding rheostat in the signal processor amplifier circuit to change the amplification factor and voltage bias of the first and second amplifier circuits, so that the waveform changes significantly when the rapeseed seeds fall; adjusting the sliding rheostat of the comparison circuit to change the threshold of the comparison circuit, setting the threshold to the amplitude outside the microwave dynamic equilibrium field when the microwave dynamic equilibrium field is stable and the amplitude inside the microwave dynamic equilibrium field when the microwave dynamic equilibrium field is destroyed, constantly changing the threshold for multiple experiments, and finally measuring and recording the resistance of each sliding rheostat, replacing the fixed resistance resistor to improve the detection stability; setting the sampling frequency of the single-chip microcomputer, determining the specific time threshold for seed re-seeding and missed seeding through experiments, and performing subsequent regulation according to the threshold.

[0023] The present invention has the following beneficial effects:

[0024] The present invention designs a rape seeding detection method based on microwave dynamic balance field, which achieves the purpose of rape seed detection by forming microwave dynamic balance field. The microwave radar module transmits linear frequency modulation continuous wave, and forms microwave dynamic balance field through reflection of the inner wall of metal aluminum box and absorption of J-type polyurethane foam absorbing material. At the same time, because the frequency and amplitude of intermediate frequency signal are related to the distance of microwave radar module wave reflection and the movement of reflector, the seeds passing through the detection area will destroy the microwave dynamic balance field. At the same time, based on the penetration characteristics of microwave for non-metal and special materials, microwave can detect multiple seeds at the same time for the inevitable overlapping phenomenon of seeds during high-frequency seeding. Therefore, when the microwave sensor detects multiple seeds passing through the detection area at the same time, it can still maintain a high accuracy, thereby effectively avoiding the phenomenon of missed detection caused by shielding. At the same time, in order to maintain the stability of microwave dynamic balance field, a photoelectric detection device is set as a microwave dynamic balance field trigger device, which can reasonably open and close the microwave dynamic balance field, prevent the device from overheating due to long-term opening of microwave field, reduce detection power consumption, and extend the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of the rapeseed seed detection method based on microwave dynamic balance field according to the present invention;

[0026] Figure 2 This is a schematic diagram of the rapeseed seed detection device of the present invention;

[0027] Figure 3 It is a schematic diagram of the photoelectric detection device of the present invention;

[0028] Figure 4 This is a schematic diagram of the intermediate frequency signal synthesis structure of the microwave radar module of the present invention;

[0029] Figure 5 This is a schematic diagram of the microwave detection device of the present invention;

[0030] Figure 6 This is a schematic diagram of the synthesis principle of the intermediate frequency signal of the microwave radar module of the present invention;

[0031] Figure 7 This is a schematic diagram of microwave dynamic balance field sampling according to the present invention;

[0032] Figure 8 A secondary signal amplification circuit diagram of the signal processor of the present invention;

[0033] Fig. 9 The filtering and voltage reduction circuit diagram of the signal processor of the present invention;

[0034] Fig.10 A signal comparison circuit diagram of the signal processor of the present invention;

[0035] Fig.11 This is a flow chart of the power supply of the microwave radar module controlled by the photoelectric detection device of the present invention.

[0036] In the figure: 1-pneumatic seed metering device; 2-rapeseed seeds; 3-seedling port; 4-photoelectric detection device; 5-microwave detection device; 6-microwave radar module; 7-switch; 8-signal processor; 9-single chip module; 10-host computer; 11-oscilloscope; 12-power supply; 13-laser emission module; 14-Fresnel collimating lens; 15-Fresnel focusing lens; 16-infrared photosensitive transistor; 17-TX transmitting antenna; 18-RX receiving antenna; 19-mixer; 20-synthesizer; 21-J-type polyurethane foam absorbing material; 22-metal aluminum box. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0038] like Figure 2 As shown, the rapeseed seeding detection device based on microwave dynamic balance field of the present invention includes a photoelectric detection device 4 and a microwave detection device 5 connected by a seeding pipe below the seeding port 3 of the pneumatic seeding device 1. The two are connected in series and powered by a power supply 12, and a switch 7 is located between the power lines of the two.

[0039] like Figure 2 , 3 As shown, the photoelectric detection device 4 includes a laser emission module 13 , a Fresnel collimating lens 14 , a Fresnel focusing lens 15 , and an infrared photosensitive transistor 16 .

[0040] like Figure 2 , 4 As shown in Figure 5, the microwave detection device 5 includes a metal aluminum box 22, and a microwave radar module 6 is installed inside the metal aluminum box 22. The signal line of the microwave radar module 6 is connected to the signal processor 8, the single-chip module 9, the host computer 10 and the oscilloscope 11. Except for the inner wall on one side facing the microwave radar module 6, the other inner walls of the metal aluminum box 22 are arranged with J-shaped polyurethane foam absorbing materials 21. The microwave radar module 6 includes a TX transmitting antenna 17, an RX receiving antenna 18, a mixer 19, and a synthesizer 20. The synthesizer 20 generates a linear frequency modulation pulse, which is transmitted by the TX transmitting antenna 17 to the metal aluminum box 22. The RX receiving antenna 18 receives the linear frequency modulation pulse reflected by the metal aluminum box 22. The mixer 19 mixes and modulates the RX signal and the TX signal to form an intermediate frequency (IF) signal.

[0041] Reference Figure 1 The rapeseed seeding detection method based on microwave dynamic balance field using the above-mentioned rapeseed seeding detection device based on microwave dynamic balance field includes the following process:

[0042] Step 1: Install the entire set below the seeding port 3 of the pneumatic seeding device 1 and connect it via a seeding pipe, wherein the photoelectric detection device 4 is located above the detection area of ​​the microwave radar module 6, and the switch 7 of the power supply 12 of the microwave radar module 6 is controlled by the photoelectric detection device 4.

[0043] Step 2: The seeding state of the seed metering device is detected by the photoelectric detection device 4 to determine whether there are rapeseed seeds 2 passing through the photoelectric detection area. When the rapeseed seeds 2 pass through the photoelectric detection area, they will block the infrared light emitted by the laser emission module 13, causing the current generated by the infrared photosensitive transistor 16 to decrease. The photoelectric detection device 4 sends a high-level seed trigger signal according to the current change. After receiving the seed trigger signal, the single-chip microcomputer module 9 will output a switch signal to the switch 7 that controls the power supply 12 of the microwave radar module 6 to conduct, so as to realize the line conduction between the microwave radar module 6 and the power supply 12. The specific process of photoelectric detection is as follows:

[0044] refer to Figure 3 The straight infrared laser emitted by the laser emission module 13 is collimated by the Fresnel collimating lens 14 to form a laser film surface, and the laser film surface is focused on the infrared photosensitive transistor 16 by the Fresnel focusing lens 15. When the rapeseed seeds 2 fall and pass through the laser film surface, part of the infrared laser is blocked, and the light flux received by the infrared photosensitive transistor 16 is reduced, and the current generated is reduced. The reduced current ΔI is:

[0045] ΔI=S·Δφ

[0046] Wherein, S is the response coefficient of the photoelectric detection device 4, which represents the current generated by unit luminous flux; Δφ is the luminous flux blocked by the rapeseed seeds 2, that is, the reduced current is proportional to the luminous flux blocked by the rapeseed seeds 2.

[0047] Step 3: Reference Figure 4 , 5 The synthesizer 20 in the microwave radar module 6 generates a linear frequency modulation pulse signal, which is transmitted by the TX transmitting antenna 17. The transmitted linear frequency modulation pulse signal propagates in the metal aluminum box 22, and is reflected back after being incident on the surface of the aluminum alloy profile facing the microwave radar module 6. The signals in other directions are absorbed by the J-shaped polyurethane foam absorbing material 21 on the inner wall of the metal aluminum box 22, forming an FMCW dynamic balance field with a fixed frequency and amplitude;

[0048] The reflection coefficient of aluminum alloy is calculated as follows:

[0049] The characteristics of the reflected wave depend on the conductivity and shape of the surface material of the object. According to the reflection coefficient formula, the reflection coefficient of the vertically incident electromagnetic wave is:

[0050]

[0051] Where R is the reflection coefficient, Z 1 is the impedance of electromagnetic waves in medium 1 (wave impedance in air), Z 2 is the impedance of electromagnetic waves in medium 2 (aluminum alloy).

[0052] A small part of the electromagnetic wave energy is absorbed by the J-shaped polyurethane foam absorbing material 21 pasted on the inner wall of the metal aluminum box 22 and converted into heat energy, which is dissipated into the air by the heat sink; the reflection loss of the absorbing material is used to describe the material's absorption effect on electromagnetic waves, expressed as:

[0053]

[0054] Where RL is the reflection loss in decibels (dB), Z in is the input impedance of the material surface, Z 0 is the wave impedance of free space, usually Z 0 =377Ω.

[0055] The ability of an absorbing material to absorb electromagnetic waves is calculated by the absorptivity A, which is defined as the proportion of incident power absorbed by the material:

[0056] A=1-MT

[0057] Among them, M is the reflectivity, which represents the part of the incident electromagnetic wave that is reflected back; T is the transmittance, which represents the part of the incident electromagnetic wave that penetrates the material.

[0058] When the material thickness is sufficient, the transmittance can be ignored, so the relationship between absorptivity and reflection loss can be simplified to:

[0059]

[0060] The J-type polyurethane foam material 21 generally has a high wave absorption performance due to its porous structure and conductive filler; within a specific frequency range, it can achieve a high reflection loss, usually between -10dB and -20dB, which means that 90% to 99% of the microwave radar module 6 wave energy can be absorbed;

[0061] The electromagnetic waves not received by the microwave radar module 6 are absorbed by 90% to 99% by the J-shaped polyurethane foam absorbing material 21 attached to the inner wall of the metal aluminum box 22. The partially reflected electromagnetic waves are also reflected to the top, bottom and left and right sides of the metal aluminum box 22 due to the conical structure of the polyurethane foam, and the impact on the microwave field in the front and rear directions is negligible. Under the continuous emission of the microwave radar module 6, the continuous reflection of the opposite metal inner wall, and the absorption of the surrounding absorbing materials, the FMCW dynamic balance field with fixed frequency and amplitude is formed.

[0062] The reflected linear frequency modulation pulse is reabsorbed and captured by the RX receiving antenna 18, and then the linear frequency modulation pulse signal transmitted by the TX transmitting antenna 17 and the linear frequency modulation pulse signal received by the RX receiving antenna 18 are combined by the mixer 19 to generate an intermediate frequency (IF) signal. The mixer 19 is an electronic component that combines the two signals to generate a new signal with a new frequency. For the specific process of mixing, refer to Figure 6 , where the upper figure shows the frequency variation of the TX and RX linear frequency modulation pulses of a single object detected over time, and the lower figure shows the frequency variation of the intermediate frequency signal over time. The horizontal and vertical axes of the two figures are frequency f and time t, τ is the time difference from transmitting the TX linear frequency modulation pulse to receiving the RX linear frequency modulation pulse, T c is the time period of a single linear frequency modulation pulse, S τ It is the frequency difference between the TX linear frequency modulation pulse and the RX linear frequency modulation pulse, that is, the frequency of the intermediate frequency IF signal.

[0063] For two sinusoidal inputs x 1 and x 2 :

[0064] x 1 = sin(ω 1 t+φ 1 ), x 2 = sin(ω 2 t+φ 2 )

[0065] Among them, x 1 is the linear frequency modulation pulse sent, x 2 is the received linear frequency modulation pulse, x out is the intermediate frequency signal, ω 1 and ω 2 x 1 and x 2 The frequency, φ 1 and φ 2 x 1 and x 2 The initial phase of , t is the time.

[0066] Output x outhas an instantaneous frequency equal to the difference between the instantaneous frequencies of the two input sine functions; the output x out The phase of is equal to the phase difference of the two input signals:

[0067] x out = sin[(ω 1 -ω 2 )t+(φ 1 -φ 2 )]

[0068] The initial phase (F0) of the IF signal is the difference between the TX chirp phase and the RX chirp phase at the time point corresponding to the start of the IF signal:

[0069] φ 0 =2πf c t

[0070] Further by We can get:

[0071] For an object at a distance d from the microwave radar module 6, the IF signal is a sine wave:

[0072] Asin(2πf 0 t+φ 0 )

[0073] in, s is the linear frequency modulation pulse frequency, λ is the dielectric constant, φ 0 represents the initial phase of the sine wave, f 0 represents the frequency of the sine wave, f c Indicates that the starting frequency of the linear frequency modulation pulse signal of the microwave radar module 6 is 24 GHz.

[0074] The oscilloscope 11 displays the intermediate frequency signal emitted by the microwave radar module 6 to facilitate observation of the signal characteristics; the oscilloscope 11 continuously collects data to obtain a microwave dynamic balance field time domain diagram, and the amplitude and frequency of the mixed signal remain consistent within the time domain range. For details, please refer to Figure 7 .

[0075] Step 4: When the rapeseed seeds 2 continue to fall and enter the detection area of ​​the microwave detection device 5, the microwave dynamic balance field will be destroyed, and the intermediate frequency signal will change. The changed signal is amplified and filtered by the improved signal amplification circuit and filtering and step-down circuit in the signal processor 8 to obtain a signal that is convenient for subsequent comparison and processing.

[0076] in:

[0077] The specific process of rapeseed 2 destroying the microwave dynamic equilibrium field is as follows:

[0078] The inner wall of the metal aluminum box 22 is fixed, and the distance from the microwave radar module 6 is a constant R 1 When the rapeseed seeds 2 fall into the metal aluminum box 22, they fall in the pipe, and the average distance from the microwave radar module 6 is set to R 2 , R 1 Obviously greater than R 2 Therefore, in the signal received by the microwave radar module 6, the echo of the metal inner wall will form a fixed intermediate frequency signal, while the echo signal of the rapeseed 2 changes due to the movement of the rapeseed 2; for the FMCW microwave radar module 6, the received signal will generate a difference frequency signal f through mixing beat , used to represent the distance of an object, and its formula is as follows:

[0079]

[0080] Where R is the object distance, R 1 is the distance from the inner wall of the metal aluminum box 22 to the microwave radar module 6, R 2 is the distance from the rapeseed seed 2 to the microwave radar module 6, c is the speed of light, B is the bandwidth of the FMCW waveform, and T is the modulation period.

[0081] For the inner wall of the metal aluminum box 22, due to its distance R 1 is fixed, so the difference frequency signal f beat1 is also fixed; for rapeseed seed 2, since rapeseed seed 2 is moving and the distance R 2 R 1 small, so the difference frequency signal f beat2 With f beat1 Different and changeable, it will cause changes in the dynamic microwave balance field, and the difference in the intermediate frequency signal can also be observed.

[0082] When the rapeseed 2 is moving, the microwave radar module 6 will detect the speed of the rapeseed 2 in addition to detecting the distance, which involves the Doppler effect. The Doppler frequency shift formula is:

[0083]

[0084] Among them, f D is the Doppler shift, v is the radial velocity of the seed, and f 1 is the center frequency of the transmitted signal. For the inner wall of the metal aluminum box 22, since it is stationary, the velocity v 1 = 0, so there is no Doppler shift; and for the moving rapeseed 2, due to its speed v 2 ≠0, so a Doppler frequency shift f will be generated D , which causes the frequency of the echo signal to shift.

[0085] At the same time, due to the characteristics of the difference frequency signal, that is, the difference between a fixed echo and a dynamic echo, for the reflection signal of the inner wall of the metal aluminum box 22, the inner wall is fixed, and when the reflection wave returns to the microwave radar module 6, due to the constant distance and no Doppler frequency shift, a stable difference frequency signal is generated. The difference frequency of this signal does not change with time. For the reflection signal of the rapeseed 2, the rapeseed 2 is constantly moving, so the reflection signal received by the microwave radar module 6 will change in time. Due to the change in the relative distance between the rapeseed 2 and the microwave radar module 6, the difference frequency signal f beat , changes with time t. In addition, due to the movement speed of rapeseed seeds 2, a Doppler frequency shift f is superimposed D , which makes the intermediate frequency signal affected by both distance changes and speed changes.

[0086] Since the microwave radar module 6 generates the intermediate frequency signal f through mixing IF It is composed of the difference frequency of the transmitted signal and the received signal. Therefore, the intermediate frequency signal reflected by the metal inner wall is stable and the frequency does not change. The intermediate frequency signal reflected by the rapeseed 22 changes with time, including different beat frequency signals caused by different relative distances and frequency shift caused by the Doppler effect. Therefore, there is a difference in the amplitude and frequency of the intermediate frequency signal when the rapeseed 22 passes and when the rapeseed 22 does not pass.

[0087] Reference Figure 8 , 9 , 10, the specific process of the signal processor 8 amplifying and filtering the intermediate frequency signal is as follows:

[0088] The signal processor 8 is used for intermediate frequency signal processing, including a weak signal secondary amplifier circuit, a filter and step-down circuit, and a signal comparison circuit. The intermediate frequency signal emitted by the microwave radar module 6 cannot achieve comparison accuracy, so the signal needs to be processed accordingly, that is, a secondary amplifier circuit is used to amplify the signal to the volt level, and a filter and step-down circuit is used to reduce the signal frequency and threshold.

[0089] The signal amplification circuit uses a two-stage amplification circuit, in which the first-stage amplification chip is AD620ARZ-REEL, and the second-stage amplification circuit is AD8421ARMZ-R7 with a higher bandwidth. The second-stage amplification circuit can amplify the voltage by more than 100,000 times. Figure 8As shown, specifically, the principle of the secondary signal amplification circuit is: Pin 1 (RG pin) of the primary amplifier chip U4 is connected to one end of the sliding resistor R14, and the other end of the sliding resistor R14 is connected to Pin 8 of the secondary amplifier chip U4, which is used to adjust the voltage bias of the primary amplifier circuit signal; Pin 2 (-IN pin) and Pin 3 (+IN pin) are respectively connected to the nodes of resistors R15 and R16, which are the signal input pins of the primary amplifier circuit, wherein the positive input or the negative input can be selected by connecting the H4 pin with an external wiring cap; Pin 4 (-VS pin) is connected to the negative power supply AVEE_5V, and is grounded through capacitors C15 and C16 at the same time. Stabilize the voltage; Pin 5 (REF pin) is connected to resistor R18, the other end of resistor R18 is connected to sliding rheostat R19, and the two ends of the sliding rheostat are respectively connected to the positive power supply AVCC_5V and the negative power supply AVEE_5V, which are used to adjust the amplification factor of the first-stage amplifier circuit signal, and the amplification factor is 1 to 10000. At the same time, pin 5 is also connected to AGND through resistor R17; pin 6 is connected to pin H3 through R20 to output the first-stage amplified signal and is connected to pin 4 (+IN pin) of the second-stage amplifier circuit chip; pin 7 (+VS pin) is connected to the positive power supply AVCC_5V, and is grounded through capacitors C17 and C18 to stabilize the voltage.

[0090] Pin 1 of the secondary amplifier chip U12 is grounded through resistor R21, indicating that the secondary amplifier input signal is a positive input; pins 2 and 3 are both RG pins, which are connected together through a sliding rheostat R28. Adjusting the sliding rheostat can adjust the voltage bias of the secondary amplifier signal; pin 4 (+IN pin) is connected to the output pin (OUTPUT pin) of the primary amplifier chip; pin 5 (-VS pin) is connected to the negative power supply AVEE_5V, and is grounded through capacitors C39 and C40 to stabilize the voltage; pin 6 (REF pin) is connected to resistor R11, and the voltage The other end of resistor R11 is connected to sliding rheostat R12, and the two ends of the sliding rheostat are respectively connected to the positive power supply AVCC_5V and the negative power supply AVEE_5V, which are used to adjust the amplification factor of the secondary amplifier circuit signal. The amplification factor is also 1 to 10000. At the same time, pin 5 is also connected to AGND through resistor R10; pin 7 (VOUTPUT pin) is connected to R13 and output pin P6 for the final amplified signal output; pin 8 (+VS pin) is connected to the positive power supply AVCC_5V, and is grounded through capacitors C22 and C21 to stabilize the voltage.

[0091] like Fig. 9As shown, specifically, the principle of the filtering and step-down circuit is: the P1 and P2 terminals are the input and output ports of the signal and the ground wire, and the high-frequency spike intermediate frequency signal is filtered into a low-frequency voltage signal through 6 2.2uf capacitors C1~C6 in parallel, so that the signal is easier to collect and compare, and then the voltage is reduced by parallel voltage division through resistors R1 (3.3KΩ) and R2 (1.6KΩ) to prevent the signal voltage value from being higher than the comparator threshold.

[0092] Step 5: Send the intermediate frequency signal after amplification, filtering and voltage reduction to the signal comparison circuit for comparison. According to the comparison result, it is determined whether there are seeds entering the detection area. The comparison circuit sends the comparison result pulse to the single-chip microcomputer module 9. After processing, the single-chip microcomputer module obtains the number of rapeseed seeds 2 and sends it to the host computer 10 through the serial port. The specific process is as follows:

[0093] The intermediate frequency signal amplified by the amplifier circuit is compared with the voltage by the signal comparison circuit to determine the number of seeds that have passed through, specifically including:

[0094] It is determined whether the voltage value of the intermediate frequency signal after the current amplification exceeds the first predetermined threshold value of the comparison circuit. If it does not exceed the first predetermined threshold value, the comparison circuit does not react; if it exceeds the first predetermined threshold value, the current detection state is in single-particle detection, and the comparison circuit outputs 1 square wave pulse; if it exceeds the second predetermined threshold value, the current detection state is in multiple-particle detection, and the comparison circuit outputs a square wave pulse number plus 1; if it exceeds the third predetermined threshold value, the current detection state is in multiple-particle detection, and the comparison circuit outputs a square wave pulse number that continues to increase by 1 on the basis of increasing by 1 after exceeding the second predetermined threshold value; wherein the third predetermined threshold value is greater than the second predetermined threshold value, the second predetermined threshold value is greater than the first predetermined threshold value, and so on, and the specific threshold value is determined by experiments.

[0095] like Fig.10As shown, specifically, the principle of the comparison circuit (unipolar) is as follows: operational amplifier U1 (ADA4665) is used for signal amplification, and its 3rd pin (+IN) is connected to the 2nd pin of the H1 interface, and the 3rd pin of H1 is connected to the power supply and the ground through the sliding rheostat R4, and the 1st pin of H1 is connected to the 4th pin of U1 and grounded together. After the 2nd and 3rd pins of H1 are connected through the short-circuit cap, the comparison threshold can be adjusted by adjusting the resistance value of the sliding rheostat R4, and the threshold can also be controlled by software by connecting the 1st and 2nd pins; the 2nd pin (-IN) of U1 Connected to the signal input terminal V- of the comparison circuit through resistor R3, pin 4 (-VS) is grounded, and pin 8 (V+) is connected to the VCC power supply; the comparison circuit P9 (TLV3501AIDR) is used for signal comparison processing, and its pin 3 (+IN) is connected to the output signal of the operational amplifier U1 for comparing the input signal level; pin 2 (-IN) is connected to R30 for stabilizing the circuit gain, and is connected to GND through a 1MΩ resistor R5 as a reference level; pin 5 (V-) is grounded, and pin 8 (V+) is connected to the VCC power supply. The output of the comparison circuit (pin 7) is connected to the interface P10 through R29 (50Ω) to provide the final comparison signal output; resistors R6 (1kΩ) and R4 (10kΩ) form a voltage divider circuit to reduce the VCC voltage to a suitable input signal level; C41, C42, C43 and C45 are 10μF and 100nF capacitors respectively, which are used for VCC power supply decoupling to ensure power supply stability and avoid high-frequency noise interference.

[0096] The single-chip microcomputer module 9 is composed of a single-chip microcomputer main control board, an LCD display screen, and a communication module, and has the functions of pulse signal reception, counting, information display and transmission. When the single-chip microcomputer module 9 receives an external pulse signal, it will count the pulse signal and update the counting information in real time through a built-in algorithm; the updated counting information will be displayed on the LCD screen at the same time, which is convenient for intuitive monitoring, and the counting information will be transmitted to the host computer through the serial communication module. In addition to completing the pulse counting function, the single-chip microcomputer module 9 is also responsible for interacting with the host computer; after receiving the counting information, the host computer will store the data in real time to ensure that key data will not be lost; at the same time, the host computer also has control functions such as count clearing, system reset, and power management.

[0097] Step 6: When the photoelectric detection device 4 does not detect the rapeseed 2 for a long time, a power-off signal is sent, the microwave radar module 6 is turned off, the dynamic balance field is turned off, and the next infrared photoelectric trigger signal is waited for. Fig.11 , the specific control logic includes:

[0098] When rapeseed seeds 2 fall, the photoelectric detection device 4 will detect that the rapeseed seeds 2 block the light path and output a high level signal. When there are no rapeseed seeds 2 blocking the light path, the output is a low level.

[0099] The single-chip microcomputer module 9 receives the photoelectric detection signal, and its input end is connected to the output end of the photoelectric detection device 4 to receive high and low level signals. Whenever a high level signal is detected, it indicates that rapeseed seeds 2 have fallen. Once a high level signal is detected, the single-chip microcomputer module 9 will think that the seeds are falling, thereby maintaining the power supply of the microwave radar module 6 (maintaining the "on" state).

[0100] A timer is set in the single-chip microcomputer module 9. When a high-level signal is received from the photoelectric detection device 4, the timer will be reset and restarted. If the photoelectric detection device 4 does not detect a high-level signal again within the set time, the timer will reach the timeout period. When the timer times out, the single-chip microcomputer module 9 will think that the interval between seed drops is too long and the photoelectric detection device 4 has not detected the seeds. At this time, the single-chip microcomputer module 9 will cut off the power supply of the microwave radar module 6 to save energy.

[0101] After receiving the high-level signal of the photoelectric detection, the single-chip microcomputer module 9 will output a control signal to an electronic switch device to maintain the power supply of the microwave radar module 6. The switch 7 device is a MOSFET. MOSFET is used for control, and its gate is connected to the output signal of the single-chip microcomputer module 9. When the single-chip microcomputer module 9 outputs a high level, the MOSFET is turned on, and the microwave radar module 6 is powered; when the single-chip microcomputer module 9 outputs a low level, the MOSFET is turned off, and the microwave radar module 6 is powered off.

[0102] MOSFET is used as a power conduction control switch. The output signal of the single-chip module 9 is connected to the gate of the MOSFET, and the power supply current of the microwave radar module 6 passes through the source-drain path of the MOSFET. When the single-chip module 9 continuously detects that rapeseed seeds 2 have fallen (the photoelectric detection device 4 outputs a high-level signal), the timer will be continuously reset, the MOSFET remains on, and the microwave radar module 6 continues to be powered. When the photoelectric detection device 4 fails to detect seeds within the set time (the timer times out), the single-chip module 9 outputs a low level, the MOSFET is turned off, and the microwave radar module 6 is powered off.

[0103] Step 7: Based on the waveform of the oscilloscope 11, adjust the amplification factor of the amplifier circuit, the comparison circuit threshold, the single chip microcomputer sampling frequency, and the replay missed broadcast time threshold, specifically including:

[0104] Observe the waveform of the oscilloscope 11 when the seeds fall, adjust the resistance of the sliding rheostat in the amplifying circuit of the signal processor 8 to change the amplification factor and voltage bias of the first and second stage amplifying circuits, so that the waveform of the rapeseed seeds 2 changes significantly when they fall; adjust the sliding rheostat of the comparison circuit to change the threshold of the comparison circuit, set the threshold to the amplitude outside the microwave dynamic equilibrium field when it is stable and to the amplitude inside the microwave dynamic equilibrium field when it is destroyed, continuously change the threshold for multiple experiments, finally measure and record the resistance of each sliding rheostat, replace the fixed resistance resistor to improve the detection stability; set the sampling frequency of the single chip computer, determine the specific time threshold when the seeds are re-seeded and missed through experiments, and perform subsequent regulation according to the threshold.

[0105] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A rapeseed seeding detection device based on microwave dynamic balance field, characterized in that: It comprises a photoelectric detection device (4) and a microwave detection device (5) which are arranged below a seeding port (3) of a pneumatic seeding device (1) and are connected by a seeding pipe. The two are connected in series and powered by a power source (12). A switch (7) is located between the power lines of the two. The photoelectric detection device (4) comprises a laser emission module (13), a Fresnel collimating lens (14), a Fresnel focusing lens (15), and an infrared photosensitive transistor (16); the laser emission module (13) emits a straight-line infrared laser which is collimated by the Fresnel collimating lens (14) to form a laser film surface, and the laser film surface is focused on the infrared photosensitive transistor (16) by the Fresnel focusing lens (15); The microwave detection device (5) comprises a metal aluminum box (22), a microwave radar module (6) is installed inside the metal aluminum box (22), a signal line of the microwave radar module (6) is connected to a signal processor (8), a single chip computer module (9), a host computer (10), and an oscilloscope (11), and except for the inner wall on one side directly facing the microwave radar module (6), the other inner walls of the metal aluminum box (22) are all arranged with a J-shaped polyurethane foam absorbing material (21); the microwave radar module (6) comprises a TX transmitting antenna (17), an RX receiving antenna (18), a mixer (19), and a synthesizer (20), the synthesizer (20) generates a linear frequency modulation pulse, and the linear frequency modulation pulse is transmitted by the TX transmitting antenna (17) into the metal aluminum box (22), the RX receiving antenna (18) receives the linear frequency modulation pulse reflected by the metal aluminum box (22), and the mixer (19) mixes and modulates the RX signal and the TX signal to form an intermediate frequency signal.

2. A method for detecting rapeseed seeding based on microwave dynamic balance field using the rapeseed seeding detection device based on microwave dynamic balance field according to claim 1, characterized in that: The process includes the following: Step 1: Install the entire set of detection devices below the seeding port (3) of the pneumatic seeding device (1), connected by a seeding pipe, and the photoelectric detection device (4) is located above the detection area of ​​the microwave radar module (6); Step 2: The seed metering device is used for seeding. When the rapeseed seeds (2) pass through the photoelectric detection area, they block the infrared light emitted by the laser emission module (13), causing the current generated by the infrared photosensitive transistor (16) to decrease. The photoelectric detection device (4) sends a high-level seed trigger signal according to the current change. After receiving the seed trigger signal, the single-chip computer module (9) outputs a switch signal to the switch (7) that controls the power supply (12) of the microwave radar module (6) to turn on. The microwave radar module (6) is turned on. Step 3: The synthesizer (20) generates a linear frequency modulation pulse signal, which is then transmitted by the TX transmitting antenna (17). The transmitted linear frequency modulation pulse signal propagates in the metal aluminum box (22), is incident on the surface of the aluminum alloy profile directly facing the microwave radar module (6), and is reflected back. The signals in other directions are absorbed by the J-shaped polyurethane foam absorbing material (21), forming a microwave dynamic balance field with a fixed frequency and amplitude; the reflected linear frequency modulation pulse is reabsorbed and captured by the RX receiving antenna (18), and then the transmitted linear frequency modulation pulse signal and the received linear frequency modulation pulse signal are combined by the mixer (19) to generate an intermediate frequency signal; the intermediate frequency signal emitted by the microwave radar module (6) is displayed in the oscilloscope (11), and is continuously collected by the oscilloscope (11) to obtain a microwave dynamic balance field time domain diagram; Step 4: When the rapeseed seeds (2) continue to fall and enter the detection area of ​​the microwave detection device (5), the microwave dynamic equilibrium field is destroyed, and the intermediate frequency signal changes. The changed signal is amplified and filtered by the improved signal amplification circuit and filtering and step-down circuit in the signal processor (8); Step 5: Send the intermediate frequency signal after amplification, filtering and voltage reduction to the signal comparison circuit in the signal processor (8) for comparison, and judge whether there are seeds entering the detection area according to the comparison result. The comparison circuit sends the comparison result pulse to the single-chip microcomputer module (9). After processing, the single-chip microcomputer module (9) obtains the number of rapeseed seeds (2) and sends it to the host computer (10) through the serial port; Step 6: When the photoelectric detection device (4) does not detect the rapeseed seeds (2) for a long time, a low-level signal is output to the single-chip microcomputer module (9), and the single-chip microcomputer module (9) cuts off the power supply of the microwave radar module (6), closes the microwave dynamic balance field, and waits for the next infrared photoelectric trigger signal; Step 7: Based on the waveform of the oscilloscope (11), adjust the amplification factor of the amplifier circuit, the threshold of the comparison circuit, the sampling frequency of the single-chip microcomputer module (9), and the replay missed time threshold.

3. The method for detecting rapeseed seeding based on microwave dynamic balance field according to claim 2, characterized in that: In step 4, the signal amplification circuit adopts a two-stage amplification circuit, wherein the first-stage amplification chip is AD620ARZ-REEL and the second-stage amplification chip is AD8421ARMZ-R7; the second-stage signal amplification circuit is specifically as follows: the 1st pin (RG pin) of the first-stage amplification chip U4 is connected to one end of the sliding resistor R14, and the other end of the sliding resistor R14 is connected to the 8th pin of the second-stage amplification chip U4, which is used to adjust the voltage bias of the first-stage amplification circuit signal; the 2nd pin (-IN pin) and the 3rd pin (+IN pin) are connected to the 4th pin (-IN pin). The first pin (-VS pin) is connected to the node of resistors R15 and R16 respectively, which is the signal input pin of the first-stage amplifier circuit, wherein the positive input or the negative input is selected by wiring the H4 pin with an external wiring cap; the 4th pin (-VS pin) is connected to the negative power supply AVEE_5V, and is grounded through capacitors C15 and C16 to stabilize the voltage; the 5th pin (REF pin) is connected to resistor R18, and the other end of resistor R18 is connected to the sliding rheostat R19, and the two ends of the sliding rheostat are respectively connected to the positive power supply AVCC_5V and the negative power supply AVEE_5V, which are used to adjust the amplification factor of the first-stage amplifier circuit signal, and the amplification factor is 1 to 10000. At the same time, the 5th pin is also connected to AGND through resistor R17; the 6th pin is connected to the pin H3 through R20 to output the first-stage amplified signal and is connected to the 4th pin (+IN pin) of the second-stage amplifier circuit chip; the 7th pin (+VS pin) is connected to the positive power supply AVCC_5V, and is grounded through capacitors C17 and C18 to stabilize the voltage; Pin 1 of the secondary amplifier chip U12 is grounded through resistor R21, indicating that the secondary amplifier input signal is a positive input; pins 2 and 3 are both RG pins, connected together through a sliding rheostat R28, and adjusting the sliding rheostat can adjust the voltage bias of the secondary amplifier signal; pin 4 (+IN Pin 5 (-VS pin) is connected to the output pin (OUTPUT pin) of the first-stage amplifier chip; Pin 5 (-VS pin) is connected to the negative power supply AVEE_5V, and is grounded through capacitors C39 and C40 to stabilize the voltage; Pin 6 (REF pin) is connected to resistor R11, and the other end of resistor R11 is connected to the sliding rheostat R12, and the two ends of the sliding rheostat are respectively connected to the positive power supply AVCC_5V and the negative power supply AVEE_5V, which are used to adjust the amplification factor of the secondary amplifier circuit signal, and the amplification factor is also 1 to 10000. At the same time, Pin 5 is also connected to AGND through resistor R10; Pin 7 (VOUTPUT pin) is connected to R13 and the output pin P6 for the final amplified signal output; Pin 8 (+VS pin) is connected to the positive power supply AVCC_5V, and is grounded through capacitors C22 and C21 to stabilize the voltage.

4. The method for detecting rapeseed seeding based on microwave dynamic balance field according to claim 2, characterized in that: In step 4, the working method of the filtering and step-down circuit is as follows: the P1 and P2 terminals are the input and output ports of the signal and the ground wire, and the high-frequency spike intermediate frequency signal is filtered into a low-frequency voltage signal through 6 2.2uf capacitors C1~C6 in parallel, so that the signal is easier to collect and compare, and then the voltage is reduced by parallel voltage division through resistors R1 (3.3KΩ) and R2 (1.6KΩ) to prevent the signal voltage value from being higher than the comparator threshold.

5. The method for detecting rapeseed seeding based on microwave dynamic balance field according to claim 2, characterized in that: In step 5, when the voltage value of the intermediate frequency signal after processing in step 4 does not exceed the first predetermined threshold value of the signal comparison circuit, the comparison circuit does not react; when it exceeds the first predetermined threshold value, the current detection state is in single-particle detection, and the comparison circuit outputs 1 square wave pulse; when it exceeds the second predetermined threshold value, the current detection state is in multiple-particle detection, and the comparison circuit outputs a square wave pulse number plus 1; when it exceeds the third predetermined threshold value, the current detection state is in multiple-particle detection, and the comparison circuit outputs a square wave pulse number that continues to increase by 1; wherein the third predetermined threshold value is greater than the second predetermined threshold value, and the second predetermined threshold value is greater than the first predetermined threshold value.

6. The method for detecting rapeseed seeding based on microwave dynamic balance field according to claim 2, characterized in that: In step 5, the working method of the comparison circuit (unipolar) is as follows: the operational amplifier U1 (ADA4665) is used for signal amplification, and its 3-pin (+IN) is connected to the 2-pin of the H1 interface, and the 3-pin of H1 is connected to the power supply and the ground through the sliding rheostat R4, and the 1-pin of H1 is connected to the 4-pin of U1 and grounded together. After the 2-pin and 3-pin of H1 are connected through the short-circuit cap, the comparison threshold can be adjusted by adjusting the resistance value of the sliding rheostat R4, and the threshold can also be controlled by software through the 1-pin and 2-pin connection software; the 2-pin (-IN) of U1 is connected to the signal input terminal V- of the comparison circuit through the resistor R3, the 4-pin (-VS) is grounded, and the 8-pin (V+) is connected to the VCC power supply; the comparison circuit P9 (TLV3501AIDR) is used for signal comparison processing, and its 3-pin (+IN) is connected to the output signal of the operational amplifier U1 for comparing the input signal level; the 2-pin (-IN) is connected to R30 for stabilizing the circuit gain, and is connected to GND through the 1MΩ resistor R5 as a reference level; Pin 5 (V-) is connected to ground, and pin 8 (V+) is connected to VCC power supply; The comparison circuit output (pin 7) is connected to the interface P10 through R29 (50Ω) to provide the final comparison signal output; the resistors R6 (1kΩ) and R4 (10kΩ) form a voltage divider circuit to reduce the VCC voltage to a suitable input signal level; C41, C42, C43 and C45 are 10µF and 100nF capacitors respectively, which are used for VCC power supply decoupling to ensure power supply stability and avoid high-frequency noise interference.

7. The method for detecting rapeseed seeding based on microwave dynamic balance field according to claim 2, characterized in that: In step 5, the single-chip microcomputer module (9) includes a single-chip microcomputer main control board, an LCD display screen, and a communication module, and has the functions of pulse signal reception, counting, information display, and transmission; when the single-chip microcomputer module (9) receives an external pulse signal, it counts the pulse signal and updates the counting information in real time through a built-in algorithm; the updated counting information is simultaneously displayed on the LCD screen, and the counting information is simultaneously transmitted to the host computer through the serial communication module; in addition to completing the pulse counting function, the single-chip microcomputer module (9) is also responsible for interacting with the host computer; after receiving the counting information, the host computer stores the data in real time.

8. The method for detecting rapeseed seeding based on microwave dynamic balance field according to claim 2, characterized in that: The step 7 comprises: observing the waveform of the oscilloscope (11) when the rapeseed (2) falls, adjusting the resistance of the sliding rheostat in the amplifying circuit of the signal processor (8) to change the amplification factor and voltage bias of the first and second amplifying circuits, so that the waveform of the rapeseed (2) when falling changes significantly; adjusting the sliding rheostat of the comparison circuit to change the threshold of the comparison circuit, setting the threshold to be outside the amplitude when the microwave dynamic equilibrium field is stable and within the amplitude when the microwave dynamic equilibrium field is destroyed, constantly changing the threshold for multiple experiments, and finally measuring and recording the resistance of each sliding rheostat, replacing the fixed resistance resistor to improve the detection stability; setting the sampling frequency of the single chip computer, determining the specific time threshold when the seeds are re-seeded and missed through experiments, and performing subsequent regulation according to the threshold.

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