A precision seeder and its hole-seeding detection device and method

Abstract

A precision seeder and its hill-seeding detection device and method are disclosed. The precision seeder includes a hill-seeding detection device comprising: a support frame mounted on the inner wall of a seed tray; a laser ranging module mounted on the support frame facing the seed-collecting tray of the seeder, used to detect whether the hill-seeder's holes have reached the detection area; a spherical capacitive sensor mounted on the support frame via a lifting mechanism, used to detect whether there are seeds in the holes; the lifting mechanism is connected to an electromagnetic relay control module, which is connected to the laser ranging module; a terahertz sensing module mounted on the support frame facing the seed-collecting tray of the seeder, used to detect whether the seeds are deteriorated or damaged; and an MCU connected to the laser ranging module, the electromagnetic relay control module, the spherical capacitive sensor, and the terahertz sensing module, respectively, used to receive information on whether the holes have reached the detection area, whether there are seeds in the holes, and / or seed quality. The invention also provides a hill-seeding detection method.

Description

Technical Field

[0001] This invention relates to agricultural sensor technology, and specifically to a precision seeder for hill-planting, as well as its seeding detection device and method. Background Technology

[0002] Existing technologies for seed detection in seeding equipment with seed guide tubes are quite mature, but they are not applicable to hill-seeding mechanical structures without seed guide tubes. This is because in hill-seeding structures, the beak directly contacts the ground to form holes, and the seeds do not pass through the inner cavity of the seed guide tube, making them undetectable by the detection devices mounted on the tube. Therefore, seed detection in hill-seeding precision seeders presents certain challenges. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a precision seeder and its hole-sowing detection device and method, which are in response to the above-mentioned defects of the prior art.

[0004] To achieve the above objectives, the present invention provides a hill-sowing detection device, wherein the hill-sowing detection device is installed on the hill-sowing device of a precision seeder, and the hill-sowing detection device includes:

[0005] The support is installed on the inner wall of the seed tray of the seed planter;

[0006] A laser ranging module is mounted on the bracket facing the seed tray of the seed planter. It is used to periodically emit laser beams and receive echoes to detect whether the seed holes of the seed planter have reached the detection area.

[0007] A spherical capacitive sensor, mounted on the bracket via a lifting mechanism, is used to detect whether there are seeds in the nest. The lifting mechanism is connected to an electromagnetic relay control module, which in turn is connected to a laser ranging module. When the laser ranging module detects a nest, it triggers the electromagnetic relay control module to control the lifting mechanism to fall, thereby raising the spherical capacitive sensor to a set detection height.

[0008] A terahertz sensing module, mounted on the bracket directly opposite the seed tray of the seed planter, is used to detect whether the seeds are spoiled or damaged; and

[0009] The MCU is connected to the laser ranging module, the electromagnetic relay control module, the spherical capacitance sensor, and the terahertz sensing module, respectively, and is used to receive information such as whether the nest has reached the detection area, whether there are seeds in the nest, and / or the quality of the seeds.

[0010] In the aforementioned hole-seeding detection device, the MCU is also connected to a host computer, transmitting the received information on the arrival of the hole in the detection area, the presence or absence of seeds in the hole, and / or the quality of the seeds to be tested to the host computer, and displaying it in real time on the PC port of the host computer.

[0011] In the aforementioned hole-seeding detection device, the lifting mechanism is located directly above the inner side of the seed tray, and the centerline of the spherical capacitive sensor is on the same straight line as the centerline of the lifting mechanism; the laser ranging module and the terahertz sensing module are located on opposite sides of the lifting mechanism, and the distance between the laser ranging module and the spherical capacitive sensor and the distance between the terahertz sensing module and the spherical capacitive sensor are equal; the extension lines of the centerlines of the laser ranging module, the spherical capacitive sensor, and the terahertz sensing module are located relative to the axis of the seed tray.

[0012] In the aforementioned hole-seeding detection device, the spherical capacitance sensor includes a spherical capacitance sensing unit and a signal acquisition and processing unit. The spherical capacitance sensing unit includes an insulating base, a spherical capacitance sensing plate, and a common plate. The common plate is mounted on the insulating base, and the spherical capacitance sensing plate is fastened to the common plate. An insulating material layer is sprayed onto the surface of the common plate to prevent the spherical capacitance sensing plate from contacting the common plate and forming a short circuit when strained.

[0013] To better achieve the above objectives, the present invention also provides a method for detecting hill-sowing seeding, comprising the following steps:

[0014] S100. Detect whether the holes on the seed tray of the seed planter have reached the detection area. The laser ranging module obtains the distance between itself and the seed tray and the area to be detected in real time, and compares it with the set distance threshold to determine whether the holes have reached the detection area.

[0015] S200. Detecting whether there are seeds in the nest: When the nest reaches the detection area, the laser ranging module sends a signal to the electromagnetic relay control module. The electromagnetic relay control module controls the lifting mechanism to lower the spherical capacitance sensor to the detection position. The spherical capacitance sensor acquires the capacitance change and compares it with a set capacitance threshold to determine whether there are seeds in the nest; and

[0016] S300. When it is determined that there are seeds in the nest, the terahertz sensing module detects whether the seeds have deteriorated or are damaged.

[0017] The above-mentioned hill-sowing detection method also includes:

[0018] S400 displays in real time on the PC port the results of whether the nest has reached the detection area, whether there are seeds in the nest, and / or the quality information of the seeds to be tested.

[0019] The above-mentioned hill-seeding detection method, wherein step S100 further includes:

[0020] S101, The laser ranging module emits continuous laser pulses;

[0021] S102. Calculate the distance D to be measured between the laser ranging module and the seed collection plate, and set the distance from the laser ranging module to the outer edge of the seed collection plate as the distance threshold TH, where TH > 0; the distance between the laser ranging module and the area to be inspected is the distance D to be measured.

[0022] S103. Calculate the flight time interval Δt between the laser ranging module and the area to be inspected; multiply Δt by the speed of light c to obtain the distance to be measured, D; and

[0023] S104. When D > TH, it is determined that the burrow has reached the detection area, and the laser ranging module sends a signal to the electromagnetic relay control module.

[0024] The above-mentioned hill-sowing detection method, wherein step S200 further includes:

[0025] S201. After receiving the signal, the electromagnetic relay control module controls the lifting mechanism to lower the spherical capacitance sensor to the detection position. The detection position is when the spherical capacitance sensor contacts the cavity in the vacant state and the surface stress of the sensing plate is zero.

[0026] S202. Measure the initial capacitance value C0 output by the spherical capacitance sensor;

[0027] S203, the lifting mechanism descends, the spherical capacitive sensor senses the pressure inside the cavity and outputs a capacitance value;

[0028] S204, The spherical capacitance sensor calculates the capacitance change ΔC; and

[0029] S205. Compare the capacitance change ΔC with the capacitance threshold th. When ΔC > th, it is determined that there are seeds in the burrow.

[0030] The above-mentioned hill-seeding detection method, wherein step S300 further includes:

[0031] S301, The terahertz sensing module emits terahertz waves toward the detection area;

[0032] S302. The seeds to be tested in the pit absorb and reflect terahertz waves, obtain the absorbance function of healthy seeds, and set the distribution range L of the characteristic peak position ω0 of the healthy seeds to the terahertz waves; and

[0033] S303. Measure the peak position ω1 of the characteristic peak absorption peak of the terahertz wave of the seed to be tested, and compare whether ω1 is within the distribution interval L. When ω1∈L, it is determined that the seed to be tested is a healthy seed; otherwise, it is determined that the seed to be tested has been damaged and deteriorated.

[0034] To better achieve the above objectives, the present invention also provides a precision seeder, which includes the above-described hole-seeding detection device and uses the above-described hole-seeding detection method for seed detection.

[0035] The technical effects of this invention are as follows:

[0036] The hole-sowing detection device of the present invention integrates laser technology, capacitive sensing and terahertz technology, and can simultaneously detect seed sowing amount and seed damage. It can promptly detect problems such as missed sowing and seed damage that prevents germination, and guide early replanting and seed replacement operations to improve crop yield.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a precision seeder according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the installation of a hole-seeding detection device according to an embodiment of the present invention;

[0040] Figure 3 This is a structural block diagram of a hole-seeding detection device according to an embodiment of the present invention;

[0041] Figure 4 This is a block diagram of a laser ranging module according to an embodiment of the present invention;

[0042] Figure 5 This is a block diagram of a spherical capacitive sensor structure according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of a spherical capacitive sensing unit structure according to an embodiment of the present invention;

[0044] Figure 7 The working principle of a spherical capacitive sensing unit according to an embodiment of the present invention;

[0045] Figure 8 This is a structural block diagram of a terahertz sensing module according to an embodiment of the present invention;

[0046] Figure 9 This is a schematic diagram illustrating the working principle of seed detection according to an embodiment of the present invention.

[0047] Among them, the attached figures are labeled

[0048] 1 type of box

[0049] 2-hole seeding device

[0050] 21 Seed Collection Tray

[0051] 22 acupoints

[0052] 23 Interval Seed Tray

[0053] 3 press wheels

[0054] 4. Covered Plate

[0055] 5 traction rods

[0056] 6-hole seeding detection device

[0057] 61 stents

[0058] 62 laser ranging module

[0059] 63 Electromagnetic Relay Control Module

[0060] 64 Lifting Mechanism

[0061] 65 spherical capacitive sensor

[0062] 651 Insulating Base

[0063] 652 common electrode plate

[0064] 653 spherical capacitor induction plate

[0065] 66 terahertz sensing module

[0066] 67MCU

[0067] 7 host computers Detailed Implementation

[0068] The structural and working principles of the present invention will be described in detail below with reference to the accompanying drawings:

[0069] See Figure 1 , Figure 1 This is a schematic diagram of a precision seeder according to an embodiment of the present invention. The precision seeder includes a seed box 1, a seeder 2, a pressing wheel 3, a covering plate 4, and a traction rod 5. The traction rod 5, seed box 1, and covering plate 4 are respectively connected to the seeder 2. The pressing wheel 3 is installed behind the covering plate 4. A seeder-type seeding detection device 6 is also installed on the seeder 2. The precision seeder is connected to a tractor via the traction rod 5 and is driven by the tractor to complete the seeding operation. During the seeding operation, the seeder 2 is one of the key components of the seeder, completing the operations of breaking the soil, opening furrows, and picking and placing the seeds. Then, the covering plate 4 and the pressing wheel 3 respectively complete the soil covering and pressing operations. Since the composition, structure, relative positions, connections, and functions of other parts of the precision seeder are all relatively mature existing technologies, they will not be described in detail here. Only the seeder-type seeding detection device 6 and its detection method of the present invention will be described in detail below.

[0070] Healthy, undamaged cotton seeds are usually coated to protect them from pests, harsh weather conditions, and other threats. Therefore, seed deterioration and damage should be avoided during sowing to prevent affecting germination rates. To detect seed deterioration and damage, it is necessary to check the seed damage in the seed tray 21 during sowing, while simultaneously checking the seed sowing quantity. Terahertz waves are electromagnetic waves with varying characteristics in different materials, including reflection, scattering, absorption, and projection. They have excellent penetrability to non-metallic materials and are highly sensitive to molecular vibrations and rotations. By utilizing the electromagnetic radiation and absorption phenomena of terahertz waves and analyzing their waveform, amplitude, phase, and other spectral characteristics, information such as the chemical composition of the seeds in the seed well 22 can be obtained, thereby enabling the detection of seed deterioration and damage in the seed well 22.

[0071] See Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the installation of the hole-seeding detection device 6 according to an embodiment of the present invention. Figure 3 This is a structural block diagram of a hill-seeding detection device 6 according to an embodiment of the present invention. The hill-seeding detection device 6 of the present invention includes: a support 61, mounted on the inner wall of the seed tray 23 of the hill seeder 2; a laser ranging module 62, mounted on the support 61 facing the seed-collecting tray 21 of the hill seeder 2, used to periodically emit laser beams and receive echoes to detect whether the holes 22 of the hill seeder 2 have reached the detection area; a spherical capacitive sensor 65, mounted on the support 61 via a lifting mechanism 64, used to detect whether there are seeds in the holes 22; the lifting mechanism 64 is connected to an electromagnetic relay control module 63, the electromagnetic relay... The control module 63 is connected to the laser ranging module 62. The electromagnetic relay control module 63 controls the descent and return of the lifting mechanism 64. When the laser ranging module 62 detects the hole 22, it triggers the electromagnetic relay control module 63 to control the lifting mechanism 64 to fall, causing the spherical capacitance sensor 65 to reach the set detection height. The terahertz sensing module 66 is mounted on the bracket 61, facing the seed tray 21 of the seed planter 2, and is used to detect whether the seeds are deteriorated or damaged. The MCU 67 (Microcontroller Unit) is connected to the laser ranging module 62, the electromagnetic relay control module 63, the spherical capacitance sensor 65, and the terahertz sensing module 66, respectively, and is used to receive information such as whether the hole 22 has reached the detection area, whether there are seeds in the hole 22, and / or the quality of the seeds to be tested.

[0072] In this embodiment, the MCU67 is also connected to the host computer 7, transmitting the received information on the arrival of the seed hole 22 in the detection area, the presence or absence of seeds in the seed hole 22, and / or the quality of the seeds to be tested to the host computer 7, and displaying it in real time on the PC port of the host computer 7. When the seed planter 2 is working, the seed picking tray 21 rotates, while the seed spacing tray 23 does not rotate with it. Therefore, the seed picking detection device 6 is installed on the inner ring of the seed spacing tray 23, directly opposite the edge of the seed picking tray 21. This seed picking detection device 6 can be equipped with a power supply module to power the laser ranging module 62, the electromagnetic relay control module 63, the lifting mechanism 64, the spherical capacitance sensor 65, the terahertz sensing module 66, and the MCU67.

[0073] See Figure 4 , Figure 4 This is a structural block diagram of a laser ranging module 62 according to an embodiment of the present invention. The detection principle of the laser ranging module 62 is based on laser pulse ranging. By performing time-domain broadening of the signal, the signal processing unit calculates the distance. After threshold comparison, it determines whether the seed pit 22 on the seed tray 21 has reached the detection area. When the seed pit 22 reaches the detection area, the laser ranging module 62 sends an arrival signal to the electromagnetic relay control module 63, thereby controlling the movement of the lifting mechanism 64 equipped with a spherical capacitance sensor 65. The laser ranging module 62 and the electromagnetic relay control module 63 communicate via serial port. The electromagnetic relay contacts are connected to the motor of the lifting mechanism 64, and the spherical capacitance sensor 65 mounted on the lifting mechanism 64 detects whether there is a seed signal in the seed pit 22. The distance from the laser ranging module 62 to the non-nest 22 area on the circumference of the seed tray 21 is set as the threshold TH (TH>0). When the distance to be measured D and the threshold TH satisfy D>TH, it is considered that the nest 22 to be inspected has reached the detection area. At this time, the lifting mechanism 64, which is equipped with a spherical capacitive sensor 65, is driven to fall to the designated position.

[0074] The laser ranging module 62 in this embodiment includes a signal generation and modulation unit, a signal acquisition and reception unit, and a signal processing unit. The signal generation and modulation unit of the laser ranging module 62 uses an SPLPL90_3 type laser light-emitting diode as the laser source to emit laser pulses. The corresponding MOSFET driving circuit is driven by a pulse control signal, releasing electrical energy to excite the laser light-emitting diode. The acquisition and reception unit uses an avalanche photodiode (APD) as a photodetector to convert and amplify the echo signal. The current signal is amplified and filtered by an amplifier circuit after passing through a current-to-voltage conversion circuit. The signal processing unit is built based on the time-to-digital converter chip TDC-GP22 to compare and process the pulse signal, converting it into a digital signal that can be processed by a microcontroller. The output is connected to the host controller STM32F103ZET6 via SPI. This MCU67 also has an I2C interface, an SPI interface, and a UART serial port, displaying the current location of the burrow 22 in the detection area on the PC.

[0075] The lifting mechanism 64 is located directly above the inner side of the seed tray 23, and the center line of the spherical capacitive sensor 65 is on the same straight line as the center line of the lifting mechanism 64. The laser ranging module 62 and the terahertz sensing module 66 are located on both sides of the lifting mechanism 64, and the distance between the laser ranging module 62 and the spherical capacitive sensor 65 and the distance between the terahertz sensing module 66 and the spherical capacitive sensor 65 are equal. This distance corresponds to the distance between adjacent holes 22 on the seed tray 21. The extension line of the center line of the laser ranging module 62, the spherical capacitive sensor 65 and the terahertz sensing module 66 is located relative to the axis of the seed tray 21.

[0076] See Figures 5-7 , Figure 5 This is a structural block diagram of a spherical capacitive sensor 65 according to an embodiment of the present invention. Figure 6 This is a schematic diagram of a spherical capacitive sensing unit structure according to an embodiment of the present invention. Figure 7This invention describes the working principle of a spherical capacitance sensing unit according to an embodiment of the present invention. The spherical capacitance sensing unit of the spherical capacitance sensor 65 is designed based on the principle of a variable plate spacing capacitor and can be simplified as an arrangement of four spatial spherical capacitance units. The spherical capacitance sensor 65 includes a spherical capacitance sensing unit and a signal acquisition and processing unit. The spherical capacitance sensing unit includes an insulating base 651, a spherical capacitance sensing plate 653, and a common plate 652. The common plate 652 is mounted on the insulating base 651, and the spherical capacitance sensing plate 653 is fastened to the common plate 652. An insulating material layer is sprayed onto the surface of the common plate 652 to prevent the spherical capacitance sensing plate 653 from contacting the common plate 652 and forming a short circuit when strained. The signal acquisition and conditioning unit of the spherical capacitance sensor 65 uses an AD7745 capacitor chip to read weak capacitance signals. A 24-bit Σ-Δ modulator converts the analog signal into a digital signal, and a digital filter processes and outputs the signal from the Σ-Δ modulator. This chip supports I2C communication and features an on-chip temperature sensor for system temperature drift compensation, eliminating the need for external components. The AD7745 capacitor chip output is connected to the STM32F103ZET6 main controller via the I2C bus, allowing the measured capacitance value to be displayed and stored on the PC.

[0077] The working principle of the spherical capacitive sensing unit of the spherical capacitive sensor 65 is as follows: Figure 7 Assume that the radii of the four spherical capacitive sensing plates 653 relative to the center of the sphere are all r, the arc length between adjacent spherical capacitive sensing plates 653 is n, the angle between each point on the spherical capacitive sensing plate 653 and the horizontal plane of the common plate 652 is θ, and the width of the projection of each point on the common plate 652 is l:

[0078]

[0079] According to the formula for calculating the capacitance C of a capacitor:

[0080]

[0081] When the included angle increases by dθ, the projection height of the spherical capacitor sensing plate 653 onto the horizontal plane of the common plate 652 is r sinθ, and the microcapacitance dC satisfies:

[0082]

[0083] Integrating the microcapacitance at each point on the spherical capacitive sensing plate 653 yields:

[0084]

[0085] Where ε0 is the vacuum permittivity, ε r is the relative permittivity.

[0086] When there is a seed in the pit 22, the spherical capacitive sensing plate 6531 deforms under the pressure of the seed, reducing the distance between the sensing plate 1 and the common plate 6522, thus causing a change in the capacitance output. Let the initial capacitances of the four spherical capacitive sensing plates 653 be C1, C2, C3, and C4, respectively. When compressed, the changes in capacitance of the four plates are ΔC1, ΔC2, ΔC3, and ΔC4, respectively. Assuming that the forces on the four spherical capacitive sensing plates 653 are equal in the tangential direction, the capacitance output of the spherical capacitive sensor 65 when it detects a seed can be calculated. The capacitance information is extracted by the signal acquisition and conditioning unit of the spherical capacitance sensor 65.

[0087] See Figure 8 , Figure 8 This is a structural block diagram of a terahertz sensing module 66 according to an embodiment of the present invention. The terahertz sensing module 66 includes an opto-mixing terahertz source and an opto-mixing detector. The opto-mixing terahertz source uses an MSM opto-device to multiply the radio frequency (RF) signal with the local oscillator signal. Simultaneously, the opto-mixing detector demodulates the signal to extract intermediate frequency (IF) information, converting each time-domain data into corresponding frequency-domain data.

[0088] When cotton seeds are damaged, the embryo is exposed or deteriorated, resulting in significant differences in its refractive index and absorption coefficient for terahertz waves compared to healthy seeds. Let E0(t) be the reference time-domain signal of the terahertz wave, and E1(t) be the time-domain signal of the seed under test after passing through the terahertz wave. After performing a Fourier transform on the time-domain signals, their frequency-domain signals are obtained as E0(ω) and E1(ω), respectively. Assume that the phase change function generated after passing through the terahertz wave is... According to Snell's law, the following formula is introduced:

[0089]

[0090] From the formulas for seed refractive index and extinction coefficient:

[0091]

[0092]

[0093] n1(ω) is the seed refractive index, κ1(ω) is the seed extinction coefficient, and for A, it can be expressed as After terahertz wave processing, the system transfer function can be approximately expressed as:

[0094]

[0095] Where c is the speed of light and d is the thickness of the medium.

[0096] Absorbance is used to represent the degree to which a seed absorbs light waves.

[0097] Absorbance1(ω)=-lg H1(ω) 2 ;

[0098] The absorption characteristics of terahertz waves in seeds within a frequency band were studied by using absorbance spectroscopy to distinguish between damaged and deteriorated seeds and healthy seeds. The characteristic peak Absorbance0(ω) of healthy seeds was set, with the peak position ω0 distributed within the L interval. When seeds are damaged or deteriorated, the absorption peak position is distributed outside the interval. At this time, it is considered that the seed quality in the hole 22 is abnormal, and healthy seeds should be replaced in time.

[0099] See Figure 9 , Figure 9 This is a schematic diagram illustrating the working principle of seed detection according to an embodiment of the present invention. The seed detection method for hill-sowing of the present invention includes the following steps:

[0100] Step S100: Detect whether the hole 22 of the seed tray 21 on the seed planter 2 has reached the detection area. The laser ranging module 62 obtains the distance between the seed tray 21 and the area to be detected in real time, and compares it with the set distance threshold to determine whether the hole 22 has reached the detection area.

[0101] Step S200: Detecting whether there are seeds in the burrow 22. When the burrow 22 reaches the detection area, the laser ranging module 62 sends a signal to the electromagnetic relay control module 63. The electromagnetic relay control module 63 controls the lifting mechanism 64 to lower the spherical capacitance sensor 65 to the detection position. The spherical capacitance sensor 65 acquires the capacitance change and compares it with a set capacitance threshold to determine whether there are seeds in the burrow 22.

[0102] Step S300: When it is determined that there are seeds in the nest 22, the terahertz sensing module 66 detects whether the seeds have deteriorated or are damaged.

[0103] This embodiment also includes:

[0104] Step S400: Display the results of whether the nest has reached the detection area, whether there are seeds in the nest, and / or the quality information of the seeds to be tested in real time on the PC port.

[0105] Step S100 further includes:

[0106] Step S101: The laser ranging module 62 emits continuous laser pulses; specifically, the signal generation and modulation unit of the laser ranging module 62 emits laser pulses, and the pulse signal generation circuit generates a pulse control signal to drive the corresponding MOSFET driving circuit, releasing electrical energy to excite the laser light emitting diode SPLPL90_3 to emit continuous laser pulses.

[0107] Step S102: Calculate the distance D to be measured between the laser ranging module 62 and the seed collection plate 21, and set the distance from the laser ranging module 62 to the outer edge of the seed collection plate 21 as the distance threshold TH, where TH > 0; the distance between the laser ranging module 62 and the area to be inspected is the distance D to be measured.

[0108] Step S103: Calculate the flight time interval Δt between the laser ranging module 62 and the area to be inspected, and multiply Δt by the speed of light c to obtain the distance to be measured D;

[0109] The distance to be measured is calculated by multiplying the laser ranging module 62 and the area to be inspected by the flight time interval, i.e., the time interval Δt between the laser pulse emission time t1 of the signal generation and modulation unit and the laser echo reception time t2 of the signal acquisition and reception unit. Δt = t2 - t1. The distance to be measured, D, is obtained by multiplying Δt by the speed of light c. The measurement of the time interval Δt is calculated by using an internal clock counter to count the number of counts from laser emission to echo signal reception. The internal clock frequency is set to f, the clock period to τ, and the number of counts for the transmission to reception process to be n. Then:

[0110] D=0.5cΔt=0.5c(t2-t1)=0.5cnτ;

[0111] Step S104: When D > TH, it is determined that the burrow 22 has reached the detection area, and the laser ranging module 62 sends a signal to the electromagnetic relay control module 63.

[0112] In this embodiment, step S200 further includes:

[0113] Step S201: After receiving the signal, the electromagnetic relay control module 63 controls the lifting mechanism 64 to lower the spherical capacitance sensor 65 to the detection position. The detection position must ensure that the spherical capacitance sensor 65 is in contact with the empty cavity 22 and the surface stress of the sensing plate is zero. The sensor is calibrated so that the output capacitance of the spherical capacitance sensor 65 does not change when there is no seed in the cavity 22.

[0114] Step S202: Measure the initial capacitance value C0 output by the spherical capacitance sensor 65;

[0115] Step S203: The lifting mechanism 64 descends, the spherical capacitive sensing unit senses the pressure inside the cavity 22 and outputs a capacitance value, which is extracted by the signal acquisition and conditioning unit of the spherical capacitive sensor 65.

[0116] Step S204: The signal acquisition and conditioning unit of the spherical capacitance sensor 65 calculates the capacitance change ΔC; and

[0117] Step S205: Compare the capacitance change ΔC with the capacitance threshold th. When ΔC > th, it is determined that there are seeds in the burrow 22.

[0118] Step S300 of this embodiment further includes:

[0119] Step S301: The terahertz sensing module 66 emits terahertz waves to the detection area; specifically, the photoelectric mixing terahertz source uses MSM photoelectric devices to multiply the radio frequency signal (RF) with the local oscillator signal and emits terahertz waves to the detection area.

[0120] Step S302: The seed to be tested in the pit 22 absorbs and reflects terahertz waves, obtains the absorbance function Absorbance0(ω) of the healthy seed, and sets the distribution range L of the characteristic peak position ω0 of the healthy seed to the terahertz wave; and

[0121] Step S303: Measure the peak position ω1 of the characteristic absorption peak of the terahertz wave of the seed to be tested, and compare whether ω1 is within the distribution interval L. If ω1∈L, the seed to be tested is determined to be a healthy seed; otherwise, the seed to be tested is determined to be damaged and deteriorated.

[0122] Before testing, the lifting mechanism 64 is adjusted to lower the spherical capacitance sensor 65 to the working position, ensuring that after the lifting mechanism 64 descends, the spherical capacitance sensor 65 is in contact with the cavity 22 (empty state) but the surface stress of the sensing plate is zero, and the initial capacitance C0 is calculated. Testing begins after calibrating the spherical capacitance sensor 65. During operation, as the seed-collecting disc 21 of the seed planter 2 rotates, the microcontroller timer generates a PWM output to drive the laser diode of the laser ranging module 62 to emit pulsed laser light. The laser echo signal is converted into a detectable electrical signal and returned as a real-time detection distance D. When the pulse measurement distance satisfies D > TH, the lifting mechanism 64 is driven to reach the working position and immediately returns along its original path. During this process, the spherical capacitance sensor 65 senses the pressure inside the cavity 22. When a seed is present in the cavity 22, the spherical capacitance sensing plate 653 deforms under pressure, outputting a capacitance value. The capacitance ΔC = C - C0 is obtained. When ΔC > th (th > 0), it is considered that there is a seed in the pit 22, where th is the threshold value of the capacitance change. If this condition is not met, it is considered that there is no seed in the seed tray 21, and reseeding is required. When the pit 22 on the seed tray 21 reaches the terahertz sensing module 66, the terahertz sensing module 66 emits continuous terahertz waves. Based on the different absorption characteristics of terahertz waves by different media, the distribution range of the characteristic peak absorption peak is determined. When the peak position is outside the healthy seed absorption peak range, it is considered that the seed is broken and the embryo is damaged and deteriorated, and the already sown seed needs to be replaced with a healthy seed.

[0123] This invention integrates laser ranging technology, capacitive sensing technology, and terahertz non-destructive testing technology, which can promptly detect problems such as missed seed sowing and damaged seeds that fail to germinate, thereby guiding early replanting and seed replacement operations and improving crop yield.

[0124] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A device for detecting the sowing of a hole sowing type, characterized in that, The hole seeding detection device is installed on a precision seeding machine, and comprises: a bracket installed on the inner wall of a seed spacing disc of the hole seeder; a laser ranging module installed on the bracket opposite to a seed taking disc of the hole seeder, for periodically emitting a laser beam and receiving a return wave to detect whether a hole of the hole seeder reaches a detection area; a spherical capacitive sensor installed on the bracket through a lifting mechanism, for detecting whether there is a seed in the hole; the lifting mechanism is connected with an electromagnetic relay control module, and the electromagnetic relay control module is connected with the laser ranging module; when the laser ranging module detects the hole, the electromagnetic relay control module is triggered to control the lifting mechanism to fall, and the spherical capacitive sensor is driven to reach a set detection height; a terahertz sensing module installed on the bracket opposite to the seed taking disc, for detecting whether a seed is deteriorated or damaged; and an MCU connected with the laser ranging module, the electromagnetic relay control module, the spherical capacitive sensor and the terahertz sensing module, respectively, for receiving information of whether the hole reaches the detection area, whether there is a seed in the hole and / or the quality of the seed; The laser ranging module emits continuous laser pulses, and the distance to be measured between the laser ranging module and the seed-taking plate is calculated by time-domain stretching of the signal. The distance from the laser ranging module to the outer edge of the seed-taking plate is set as a distance threshold. , The distance between the laser ranging module and the area to be inspected is the distance to be measured. ;satisfy When the laser ranging module determines that the cavity to be inspected has reached the detection area, it sends a signal to the electromagnetic relay control module, which drives the lifting mechanism to lower the spherical capacitive sensor to the designated position.

2. The singulation detection device of claim 1, wherein the MCU is also connected with an upper computer, and transmits the received information of whether the hole reaches the detection area, whether there is a seed in the hole and / or the quality of the seed to be detected to the upper computer and displays the information on a PC port of the upper computer in real time.

3. The singulation detection device of claim 1, wherein The lifting mechanism is located directly above the inner side of the seed spacing disc, the center line of the spherical capacitive sensor is located on the same line as the center line of the lifting mechanism; the laser ranging module and the terahertz sensing module are located on the two sides of the lifting mechanism, respectively, and the distance between the laser ranging module and the spherical capacitive sensor is equal to the distance between the terahertz sensing module and the spherical capacitive sensor; the center lines of the laser ranging module, the spherical capacitive sensor and the terahertz sensing module are extended to the axis of the seed taking disc.

4. The singulation detection device of claim 1, wherein, The spherical capacitive sensor comprises a spherical capacitive sensitive unit and a signal acquisition and processing unit, the spherical capacitive sensitive unit comprises an insulating base frame, a spherical capacitive sensing electrode plate and a common electrode plate, the common electrode plate is installed on the insulating base frame, the spherical capacitive sensing electrode plate is buckled on the common electrode plate, and an insulating material layer is sprayed on the surface of the common electrode plate to avoid the spherical capacitive sensing electrode plate from contacting the common electrode plate to form a short circuit when the spherical capacitive sensing electrode plate is strained.

5. A method of detecting a hole sowing, characterized by, The hole seeding detection device comprises the following steps: S100, detecting whether a hole of a seed taking disc of a hole seeder reaches a detection area, a laser ranging module obtains a distance between the seed taking disc and the detection area in real time, compares the distance with a set distance threshold, and judges whether the hole reaches the detection area; S200, detecting whether there is a seed in the hole, when the hole reaches the detection area, the laser ranging module sends a signal to the electromagnetic relay control module, the electromagnetic relay control module controls the lifting mechanism to drive the spherical capacitive sensor to descend to the detection position, the spherical capacitive sensor obtains the capacitance change and compares it with the set capacitance threshold to judge whether the hole has a seed; And S300, when it is judged that the hole has a seed, the terahertz sensing module detects whether the seed is deteriorated or damaged; Wherein, step S100 further comprises: S101, the laser ranging module emits continuous laser pulses; S102、calculating the distance to be measured between the laser ranging module and the seed disc , setting the distance from the laser ranging module to the outer edge of the seed disc as a distance threshold , ; the distance between the laser ranging module and the area to be detected is the distance to be measured ; S103, calculate the time-of-flight interval between the laser ranging module and the region to be detected , and the speed of light to obtain the distance to be measured ; and S104、When the condition is met at this time, the laser ranging module sends a signal to the electromagnetic relay control module.

6. The method of claim 5, wherein the hole is formed by a hole puncher. Also includes: S400, real-time display of the hole reaching the detection area, the presence or absence of seeds in the hole and / or the quality information of the seed to be detected on the PC port.

7. The method of claim 5, wherein the hole is formed by a hole puncher. Step S200 further comprises: S201, after receiving the signal, the electromagnetic relay control module controls the lifting mechanism to drive the spherical capacitive sensor to descend to the detection position, and the detection position is that the spherical capacitive sensor contacts the hole in the empty hole state and the surface stress of the sensing electrode plate is zero; S202, measure an initial capacitance value output by the spherical capacitive sensor ; S203, the lifting mechanism falls, the spherical capacitive sensor senses the pressure in the hole, and feeds back the output capacitance value; S204, the spherical capacitive sensor calculates a capacitive variation amount ; and S205, compare the capacitance change amount with the capacitance threshold value when determine that the nest has seeds.

8. The method of claim 7, wherein the hole is formed by a hole puncher. Step S300 further comprises: S301, the terahertz sensing module emits terahertz waves to the detection area; S302, the seed to be measured in the cavity absorbs the reflected terahertz wave, the healthy seed absorbance function is obtained, and the characteristic peak absorption peak position of the healthy seed to the terahertz wave is set The distribution interval of the characteristic peak absorption peak position of the healthy seed to the terahertz wave ; and S303, measuring a characteristic peak absorption peak position of the to-be-tested seed to terahertz waves , comparing whether the distribution interval , when , judging that the to-be-tested seed is healthy, otherwise judging that the to-be-tested seed appears to be damaged or deteriorated.

9. A precision planter characterized by, The hole seeding detection device of any one of claims 1-4 is adopted, and the seed detection is carried out by the hole seeding detection method of any one of claims 5-8.

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