A rice seedling tray seeding amount variable weighing device and a variable weighing method

Abstract

The present application relates to the field of agricultural detection technology, in particular to a kind of rice seedling tray seeding amount variable speed weighing device and variable speed weighing method, including rack, weighing device, variable speed drive device, positioning device and control system, wherein variable speed drive device drives seedling tray from back to front to carry out variable speed movement, so that seedling tray dynamic carries, static weighing, weighing device accurately weighs the mass of seedling tray, positioning device accurately locates whether seedling tray enters weighing position, control system can receive weighing data and carry out algorithm processing, finally obtain the final measurement result of seedling tray.The variable speed weighing device in the present application realizes seedling tray dynamic carrying, static weighing, also realizes seedling tray automatic continuous rapid weighing, weighing precision is high, improves production efficiency.The variable speed weighing method described in the present application can make seedling tray keep interval with front and rear seedling tray when weighing, avoid mechanical interference, improve weighing precision, and has high practical value.

Description

Technical Field

[0001] This invention relates to the field of agricultural testing technology, specifically to a variable-speed weighing device for rice seedling trays, and also to a variable-speed weighing method for rice seedling trays. Background Technology

[0002] The accuracy of the amount of rice seedlings sown in the seedling trays directly affects the quality of rice seedlings, which in turn affects the quality of transplanting. Therefore, the accuracy of weighing the seedling trays before and after sowing is crucial.

[0003] The existing seedling tray sowing quantity is mainly achieved by pre-calibration. When the seed moisture content and variety change, the seedling tray sowing quantity changes greatly, affecting the seedling quality. The existing weighing device has the following problems: (1) Due to the continuous conveying of seedling trays during seedling raising, there is no gap between the seedling tray and the seedling trays before and after when the seedling tray reaches the weighing position, which causes the seedling tray to contact the seedling trays before and after when weighing, which causes certain interference to the measurement accuracy; (2) The weighing position positioning device uses a diffuse reflection photoelectric sensor. Due to the scattering problem itself, there is a deviation in the predicted position of the weighing seedling tray; (3) The device uses a microcontroller as the control core. However, the microcontroller has poor anti-interference ability and is greatly affected by environmental factors such as strong and weak electricity, climate and temperature. Its working stability is poor under complex field conditions. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the purpose of this invention is to provide a variable-speed weighing device for rice seedling trays, which can realize dynamic transport and static weighing of seedling trays, thereby improving weighing accuracy and stability.

[0005] Another objective of this invention is to provide a variable-speed weighing method for rice seedling trays, which enables the seedling trays to maintain a certain distance from the front and rear seedling trays during weighing, thereby reducing mechanical interference between the seedling trays and improving weighing accuracy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A variable-speed weighing device for rice seedling tray seeding includes a frame, a weighing device, a variable-speed drive device, a positioning device, and a control system. The variable-speed weighing device is used to weigh the seeding quantity of the seedling tray. The frame is arranged horizontally across the front and rear directions. The variable-speed drive device, positioning device, and control system are all mounted on the frame. The variable-speed drive device is used to drive the seedling tray to move at varying speeds from back to front. It includes a front drive assembly, a variable-speed drive assembly, and a rear drive assembly arranged sequentially from front to back on the frame. The weighing device is located below the variable-speed drive assembly and is separate from the frame. It includes a support frame, a base plate, a weighing sensor, a load-bearing frame, and a mudguard arranged sequentially from bottom to top. Support wheel sets are respectively arranged on the front and rear sides of the load-bearing frame. The support wheel sets are located at the intervals between the rear drive assembly, the transmission drive assembly, and the front drive assembly. The front drive assembly and the rear drive assembly each include multiple sets of spaced rubber drive wheels. The transmission drive assembly includes a front drive wheel and a rear drive wheel. The tops of the rubber drive wheels, the front drive wheel, and the rear drive wheel are flush with and lower than the top of the support wheel sets. The front drive wheel and the rear drive wheel have the same radius. The radius of the rubber drive wheel is smaller than the radius of the front drive wheel and the rear drive wheel. The axis of the front drive wheel and the rear drive wheel is lower than the axis of the rubber drive wheel. The rubber drive wheel, the front drive wheel, and the rear drive wheel rotate at the same speed. The linear velocity of the rubber drive wheel is V0, and the linear velocity of the front drive wheel and the rear drive wheel is V1, where V1 is greater than V0.

[0008] Furthermore, there is a height difference ΔZ1 between the transmission drive unit and the top of the support wheel assembly; there is a height difference ΔZ2 between the axle of the front drive wheel, the rear drive wheel and the axle of the rubber drive wheel.

[0009] Furthermore, the support wheel assembly includes a front support wheel and a rear support wheel located on the front and rear sides of the load-bearing frame; wherein the front support wheel is located at the interval between the front drive assembly and the transmission drive assembly, and the rear support wheel is located at the interval between the transmission drive assembly and the rear drive assembly.

[0010] Furthermore, the positioning device includes a through-beam photoelectric sensor emitter, a through-beam photoelectric sensor receiver, and a mounting plate; the through-beam photoelectric sensor emitter and the through-beam photoelectric sensor receiver are both fixed above the frame by the mounting plate and are located on the left and right sides of the front support wheel; the positioning device is used to identify whether the seedling tray has reached the weighing position.

[0011] Furthermore, the control system is electrically connected to the weighing sensor and positioning device; the control system includes a pulse signal receiving unit, a data acquisition unit, a data processing unit, a human-machine interaction unit, and a power supply unit; wherein the data acquisition unit includes a digital transmitter.

[0012] A method for weighing the seeding rate of rice seedling trays using a variable-speed weighing device as described above; the method includes:

[0013] S1: Turn on the variable speed weighing device and place the seedling trays to be weighed onto the rear drive assembly in sequence.

[0014] S2: The rear drive assembly drives the seedling tray to be weighed to start moving at a speed of V0;

[0015] S3: When the seedling tray to be weighed moves to the rear support wheel, the front end of the seedling tray to be weighed begins to contact the rear support wheel and climbs up along the rear support wheel. After the center of mass passes the rear support wheel, the rear end of the seedling tray to be weighed separates from the rear drive assembly, and the front end contacts the front drive wheel.

[0016] S4: The front drive wheel drives the seedling tray to be weighed to move at a speed of V1. At this time, the distance between the seedling tray to be weighed and another seedling tray to be weighed located behind it increases.

[0017] Until the front end of the seedling tray to be weighed contacts the front support wheel and begins to climb upwards by inertia, after the front end of the seedling tray to be weighed climbs onto the front support wheel, it comes to a brief stop on the support wheel assembly under the action of friction. At this time, the next seedling tray to be weighed continues to move forward, and the distance between it and the seedling tray that is stationary on the support wheel assembly is reduced.

[0018] The positioning device detects that the seedling tray to be weighed has reached the preset weighing position and transmits a pulse signal to the control system. After the pulse signal receiving unit receives the pulse signal, the control system controls the weighing sensor to start weighing the seedling tray that is stationary on the support wheel assembly. The weighing sensor outputs the obtained weighing data to the control system in the form of an analog signal.

[0019] S5: When the next seedling tray to be weighed touches the seedling tray that is stationary on the support wheel group, the next seedling tray to be weighed pushes the seedling tray on the support wheel group to move forward. At this time, one weighing is completed. The data acquisition unit obtains an analog signal from the weighing sensor. After the weighing is completed, the seedling tray continues to move forward. When the rear end of the seedling tray falls from the rear support wheel to the rear drive wheel, the rear drive wheel drives the seedling tray to move forward at a speed of V1.

[0020] S6: After weighing, the seedling tray continues to move forward under the drive of the speed change drive assembly. At this time, the distance between the weighed seedling tray and the next seedling tray to be weighed increases until the center of mass of the weighed seedling tray passes through the front support wheel. At this time, the rear end of the weighed seedling tray separates from the speed change drive assembly, and the front end begins to contact the front drive assembly. The front drive assembly begins to drive the weighed seedling tray to continue moving forward.

[0021] S7: Repeat steps S2 to S6 for the next seedling tray to be weighed until the second to last seedling tray to be weighed is finished;

[0022] S8: The last seedling tray to be weighed is weighed by human intervention.

[0023] Furthermore, in step S4, when the seedling tray reaches the detection position, i.e. the seedling tray weighing position, the light beam emitted by the light emitter of the through-beam photoelectric sensor is blocked by the seedling tray, and the through-beam photoelectric sensor receiver cannot receive the light beam. At this time, the output signal of the through-beam photoelectric sensor receiver changes from low level to high level, and the pulse signal receiving unit of the control system receives a rising edge signal, i.e., a pulse signal, indicating that the seedling tray has reached the weighing position. The data acquisition unit starts to receive and read the analog signal from the weighing sensor, and the digital transmitter amplifies the analog signal output by the weighing sensor and converts it into a digital signal, which is then transmitted to the data processing unit.

[0024] Furthermore, the data processing unit first extracts relatively stable weighing data from the digital signal to obtain a set of real measurement value datasets. Then, it performs noise reduction processing on the collected weighing data using a scalar Kalman filter algorithm to obtain an optimized dataset. Finally, it processes the optimized dataset using a median average filter algorithm to obtain the final weighing result of the seedling tray quality.

[0025] Furthermore, the scalar Kalman filter algorithm consists of two processes: prediction and update. The prediction process uses the estimate of the previous state to make an estimate of the current state; the update process uses the observation of the current state to optimize the predicted value obtained in the prediction stage, so as to obtain a more accurate optimal estimate x. k|k :

[0026] Prediction equation:

[0027]

[0028] Update equation:

[0029]

[0030] Where, x k|k-1 The current state result predicted using the optimal estimate at time k-1; x k-1|k-1 The optimal estimate at time k-1; u k p is the control gain for the current state. k-1|k-1 p is the covariance of the estimated values ​​at time k-1; k|k-1 The current covariance result is predicted using the covariance at time k-1; a is the state transition coefficient; b is the input gain coefficient; q is the excitation noise; h is the measurement coefficient; r is the measurement noise; g k The optimal Kalman gain at time k; z k x is a true measurement value at time k, i.e., the dataset of true measurement values; k|k p represents the optimal estimate at time k, i.e., the optimized dataset; k|k Let be the covariance of the estimated value at time k.

[0031] Furthermore, the median average filtering algorithm evaluates the n optimal estimates x after noise reduction. k|k The process involves first sorting the n data points from smallest to largest, then removing the minimum values ​​(m1) and maximum values ​​(m2), and finally averaging the n-m1-m2 optimal estimates.

[0032]

[0033] Where M represents the final weighing result of the seedling tray.

[0034] The present invention has the following advantages:

[0035] 1. The variable speed weighing device of the present invention has a variable speed drive device, a positioning device and a control system mounted on a frame, and the weighing device is separated from the frame. This allows the seedling tray to be dynamically carried above the frame by the variable speed drive device and statically weighed above the weighing device. Furthermore, since the weighing device is separated from the frame, the influence of the mechanical vibration of the frame on the weighing accuracy is eliminated, resulting in more accurate weighing results.

[0036] 2. The variable speed weighing method of the present invention uses a variable speed drive device to enable the seedling trays to be transported at different speeds on the frame. When weighing at rest, a certain distance is maintained between the seedling trays in front and behind, so that the seedling trays in front and behind do not mechanically interfere with the seedling trays weighing at rest on the weighing device. This makes the weighing results more accurate and reliable. After the weighing is completed, each seedling tray on the frame continues to move forward continuously, realizing automated, continuous and rapid weighing, which greatly improves the weighing efficiency and thus improves the production efficiency.

[0037] 3. In the variable speed weighing device of the present invention, the positioning device for identifying whether the seedling tray has reached the weighing position adopts a through-beam photoelectric sensor, which has a fast response speed and the detection distance is not affected by the color and structure of the target object, thus making the weighing accuracy higher.

[0038] 4. In the variable speed weighing device of the present invention, the control system adopts Mitsubishi PLC, which has the advantages of strong anti-interference ability, large noise tolerance, not easily affected by strong electromagnetic interference generated by frequency converters, motors, etc., high stability, and can work in complex and variable field environments such as temperature and humidity.

[0039] 5. In the variable speed weighing method of the present invention, a scalar Kalman filter algorithm is used to preprocess the collected weighing data for noise reduction, and then the mass of the seedling tray is obtained by the median average filter algorithm. The data processing accuracy is high, the stability is good, and the confidence of the processing results is high.

[0040] 6. The variable speed weighing device in this invention can be used not only for rice, but also for quality weighing in other seedling production lines such as flowers and fruits and vegetables. It has reliable performance and practical application value. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the variable speed weighing device in this invention.

[0042] Figure 2 This is a side view of the variable speed weighing device of the present invention.

[0043] Figure 3 This is an exploded view of the variable speed weighing device in this invention.

[0044] Figure 4 This is a schematic diagram of the speed change drive device of the speed change weighing device in this invention.

[0045] Figure 5 This is a schematic diagram of the positioning device of the variable speed weighing device in this invention.

[0046] Figure 6 This is a schematic diagram of the speed change drive assembly of the speed change weighing device in this invention.

[0047] Figure 7 This is a top view of the weighing position of the variable speed weighing device in this invention.

[0048] Figure 8 This is a hardware principle block diagram of the variable speed weighing device control system in this invention.

[0049] Figure 9 This is a schematic diagram of the state of the seedling tray to be weighed before it is driven by the front drive wheel in step S3 of the present invention.

[0050] Figure 10 This is a schematic diagram of the state of the seedling tray to be weighed climbing upward along the front support wheel in step S4 of the present invention.

[0051] Figure 11 This is a schematic diagram showing the state of the front end of the seedling tray to be weighed climbing up to the front support wheel in step S4 of the present invention.

[0052] Figure 12 This is a schematic diagram showing the collision state between the last seedling tray to be weighed and the seedling tray stationary on the support wheel assembly in step S5 of the present invention.

[0053] Figure 13 This is a schematic diagram showing the state of the seedling tray falling onto the front drive assembly after weighing is completed in step S6 of the present invention.

[0054] in,

[0055] 1 is the rack.

[0056] 2 is the weighing device, 21 is the support frame, 22 is the base plate, 23 is the load cell, 24 is the load-bearing frame, 25 is the mudguard, 26 is the support wheel assembly, 261 is the front support wheel, and 262 is the rear support wheel.

[0057] 3 is the transmission drive unit, 31 is the front drive assembly, 311 is the rubber drive wheel, 32 is the transmission drive assembly, 321 is the front drive wheel, 322 is the rear drive wheel, and 33 is the rear drive assembly.

[0058] 4 is the positioning device, 41 is the emitter of the through-beam photoelectric sensor, 42 is the receiver of the through-beam photoelectric sensor, and 43 is the mounting plate.

[0059] 5 is the control system.

[0060] 6 is the seedling tray, 61 is the seedling tray to be weighed, 62 is the next seedling tray to be weighed, and 63 is the seedling tray after weighing. Detailed Implementation

[0061] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0062] like Figures 1 to 8 As shown, a variable speed weighing device for rice seedling tray seeding includes a frame, a weighing device, a variable speed drive device, a positioning device, and a control system. The variable speed weighing device is used to weigh the seeding amount of the seedling tray. The frame is arranged across the front and rear directions. The variable speed drive device, the positioning device, and the control system are all installed on the frame.

[0063] The variable speed drive device is used to drive the seedling tray to perform variable speed movement from back to front, and includes a front drive assembly, a variable speed drive assembly and a rear drive assembly arranged sequentially from front to back on the frame.

[0064] The weighing device is located below the transmission drive assembly and is separate from the frame. It includes a support frame, a base plate, a weighing sensor, a load-bearing frame, and a mudguard arranged sequentially from bottom to top. Support wheel sets are provided on the front and rear sides of the load-bearing frame, and the two sets of support wheel sets are located at the intervals between the rear drive assembly, the transmission drive assembly, and the front drive assembly, respectively.

[0065] Specifically, the weighing device is separated from the frame, eliminating the impact of mechanical vibration on weighing accuracy. A variable speed drive device is used to drive the seedling trays, enabling the seedling trays to be continuously and dynamically transported on the frame for static weighing. This avoids contact between the seedling trays and the front and rear seedling trays during weighing, improving weighing accuracy and resulting in higher confidence of the weighing data values.

[0066] In this embodiment, an electromagnetic force-type load cell is used, which has high weighing accuracy, fast response speed, and good stability.

[0067] like Figure 4As shown, both the front drive assembly and the rear drive assembly include multiple sets of spaced rubber drive wheels. The transmission drive assembly includes a front drive wheel and a rear drive wheel. The tops of the rubber drive wheels, the front drive wheel, and the rear drive wheel are flush with each other and lower than the top of the support wheel set. The front drive wheel and the rear drive wheel have the same radius, while the radius of the rubber drive wheel is smaller than that of the front drive wheel and the rear drive wheel. The axis of the front drive wheel and the rear drive wheel is lower than that of the rubber drive wheel. The rubber drive wheel, the front drive wheel, and the rear drive wheel rotate at the same speed. The linear velocity of the rubber drive wheel is V0, and the linear velocity of the front drive wheel and the rear drive wheel is V1, where V1 is greater than V0.

[0068] like Figure 6 As shown, in this embodiment, there is a height difference ΔZ1=2mm between the top of the transmission drive device and the support wheel assembly; there is a height difference ΔZ2=2mm between the axle of the front drive wheel, the rear drive wheel and the axle of the rubber drive wheel.

[0069] Specifically, the tops of the rubber drive wheel, front drive wheel, and rear drive wheel are flush. The radius of the front drive wheel and rear drive wheel is R2=27mm, and the radius of the rubber drive wheel is R1=25mm. The front drive wheel and rear drive wheel have the same radius. The radius of the rubber drive wheel is smaller than that of the front drive wheel and rear drive wheel. Therefore, the axis of the front drive wheel and rear drive wheel is lower than the axis of the rubber drive wheel by ΔZ2=2mm.

[0070] In this embodiment, there is a height difference ΔZ1=2mm between the support wheel assembly and the transmission drive device, which allows the seedling tray to separate from the rear drive assembly in time when entering the transmission drive assembly, thus avoiding mechanical interference. Similarly, the seedling tray can also separate from the transmission drive assembly in time when entering the front drive assembly, thus avoiding mechanical interference. This setting further avoids the influence of other mechanical components on the weighing process of the weighing device when the seedling tray enters and exits the weighing position, further improving the accuracy of weighing and making the generated data more reliable.

[0071] like Figure 5 and 7 As shown, the positioning device includes a through-beam photoelectric sensor emitter, a through-beam photoelectric sensor receiver, and a mounting plate; the through-beam photoelectric sensor emitter and the through-beam photoelectric sensor receiver are both fixed above the frame by the mounting plate and are located on the left and right sides of the front support wheel; the positioning device is used to identify whether the seedling tray has reached the weighing position.

[0072] In this embodiment, the positioning device uses a through-beam photoelectric sensor, which has a fast response speed and the detection distance is not affected by the color and structure of the target object, resulting in higher weighing accuracy.

[0073] like Figure 8As shown, the control system is electrically connected to the weighing sensor and the positioning device; the control system includes a pulse signal receiving unit, a data acquisition unit, a data processing unit, a human-machine interaction unit, and a power supply unit; wherein the data acquisition unit includes a digital transmitter.

[0074] In this embodiment, the control system uses a Mitsubishi PLC, which has the advantages of strong anti-interference ability, large noise tolerance, is not easily affected by strong electromagnetic interference generated by frequency converters, motors, etc., has high stability, and can work in complex and variable field environments such as temperature and humidity.

[0075] Specifically, when the seedling tray reaches the detection position, i.e. the seedling tray weighing position, the light beam emitted by the through-beam photoelectric sensor is blocked by the seedling tray, and the through-beam photoelectric sensor receiver cannot receive the light beam. At this time, the output signal of the through-beam photoelectric sensor receiver changes from low level to high level, and the pulse signal receiving unit of the control system receives a rising edge signal, i.e., a pulse signal, indicating that the seedling tray has reached the weighing position. The data acquisition unit starts to receive and read the analog signal from the weighing sensor, and the digital transmitter amplifies the analog signal output by the weighing sensor and converts it into a digital signal, which is then transmitted to the data processing unit.

[0076] The human-computer interaction unit is used by staff to perform related operations; the power supply unit is used to supply power to the control system, photoelectric sensor, weighing sensor, etc.

[0077] like Figures 8 to 12 As shown, a method for weighing the seeding rate of rice seedling trays using a variable-speed weighing device as described above is provided; the method includes:

[0078] S1: Turn on the variable speed weighing device and place the seedling trays to be weighed onto the rear drive assembly in sequence.

[0079] S2: The rear drive assembly drives the seedling tray to be weighed to start moving at a speed of V0;

[0080] S3: When the seedling tray to be weighed moves to the rear support wheel, the front end of the seedling tray to be weighed begins to contact the rear support wheel and climbs up along the rear support wheel. After the center of mass passes the rear support wheel, the rear end of the seedling tray to be weighed separates from the rear drive assembly, and the front end contacts the front drive wheel.

[0081] S4: The front drive wheel drives the seedling tray to be weighed to move at a speed of V1. At this time, the distance between the seedling tray to be weighed and another seedling tray to be weighed located behind it increases.

[0082] Until the front end of the seedling tray to be weighed contacts the front support wheel and begins to climb upwards by inertia, after the front end of the seedling tray to be weighed climbs onto the front support wheel, it comes to a brief stop on the support wheel assembly under the action of friction. At this time, the next seedling tray to be weighed continues to move forward, and the distance between it and the seedling tray that is stationary on the support wheel assembly is reduced.

[0083] The positioning device detects that the seedling tray to be weighed has reached the preset weighing position and transmits a pulse signal to the control system. After the pulse signal receiving unit receives the pulse signal, the control system controls the weighing sensor to start weighing the seedling tray that is stationary on the support wheel assembly. The weighing sensor outputs the obtained weighing data to the control system in the form of an analog signal.

[0084] S5: When the next seedling tray to be weighed touches the seedling tray that is stationary on the support wheel group, the next seedling tray to be weighed pushes the seedling tray on the support wheel group to move forward. At this time, one weighing is completed. The data acquisition unit obtains an analog signal from the weighing sensor. After the weighing is completed, the seedling tray continues to move forward. When the rear end of the seedling tray falls from the rear support wheel to the rear drive wheel, the rear drive wheel drives the seedling tray to move forward at a speed of V1.

[0085] S6: After weighing, the seedling tray continues to move forward under the drive of the speed change drive assembly. At this time, the distance between the weighed seedling tray and the next seedling tray to be weighed increases until the center of mass of the weighed seedling tray passes through the front support wheel. At this time, the rear end of the weighed seedling tray separates from the speed change drive assembly, and the front end begins to contact the front drive assembly. The front drive assembly begins to drive the weighed seedling tray to continue moving forward.

[0086] S7: Repeat steps S2 to S6 for the next seedling tray to be weighed until the second to last seedling tray to be weighed is finished;

[0087] S8: The last seedling tray to be weighed is weighed by human intervention.

[0088] Specifically, in step S3, such as Figure 9 As shown, after the center of mass passes the rear support wheel, the rear end of the seedling tray to be weighed begins to separate from the rear drive assembly, and the front end begins to contact the front drive wheel. At this time, the speed of the seedling tray is V0.

[0089] In step S4, as Figure 10 As shown, the seedling tray to be weighed is driven by the front drive wheel and moves forward at a speed of V1. The front end of the seedling tray contacts the front support wheel and begins to climb upward by inertia.

[0090] In step S4, as Figure 11 As shown, after the front end of the seedling tray to be weighed climbs up to the front support wheel, it comes to a brief stop on the support wheel assembly under the action of friction. At this time, the next seedling tray to be weighed continues to move forward, and the distance between it and the seedling tray that is stationary on the support wheel assembly is reduced.

[0091] In step S5, as Figure 12As shown, when the next seedling tray to be weighed touches the seedling tray that is stationary on the support wheel set, the next seedling tray to be weighed pushes the seedling tray on the support wheel set forward.

[0092] In step S6, as Figure 13 After weighing, the rear end of the seedling tray separates from the transmission drive assembly, and the front end begins to contact the front drive assembly. The front drive assembly begins to drive the seedling tray to continue moving forward after weighing. At this time, the seedling tray continues to move forward at a speed of V0.

[0093] In this invention, the process of weighing the seedling tray by cooperating with the positioning device, weighing device, and control system is as follows:

[0094] When the seedling tray reaches the weighing position, the light beam emitted by the through-beam photoelectric sensor is blocked by the seedling tray, and the through-beam photoelectric sensor receiver cannot receive the light beam. At this time, the output signal of the through-beam photoelectric sensor receiver changes from low level to high level. The pulse signal receiving unit of the control system receives a rising edge signal, indicating that the seedling tray has reached the weighing position. The data acquisition unit of the control system starts to receive and read the analog signal from the weighing sensor. The digital transmitter amplifies the analog signal output by the weighing sensor and converts it into a digital signal and transmits it to the data processing unit.

[0095] In this invention, the data processing method for the seedling tray is as follows:

[0096] The data processing unit first extracts relatively stable weighing data from the digital signal to obtain a set of real measurement value datasets. Then, it performs noise reduction processing on the collected weighing data using a scalar Kalman filter algorithm to obtain an optimized dataset. Finally, it processes the optimized dataset using a median average filter algorithm to obtain the final weighing result of the seedling tray quality.

[0097] The scalar Kalman filter algorithm consists of two processes: prediction and update. The prediction process uses the estimate of the previous state to estimate the current state; the update process uses the observations of the current state to optimize the predicted value obtained in the prediction stage, thereby obtaining a more accurate optimal estimate x. k|k :

[0098] Prediction equation:

[0099]

[0100] Update equation:

[0101]

[0102] Where, x k|k-1 The current state result predicted using the optimal estimate at time k-1; x k-1|k-1The optimal estimate at time k-1; u k p is the control gain for the current state. k-1|k-1 p is the covariance of the estimated values ​​at time k-1; k|k-1 The current covariance result is predicted using the covariance at time k-1; a is the state transition coefficient; b is the input gain coefficient; q is the excitation noise; h is the measurement coefficient; r is the measurement noise; g k The optimal Kalman gain at time k; z k x is a true measurement value at time k, i.e., the dataset of true measurement values; k|k p represents the optimal estimate at time k, i.e., the optimized dataset; k|k Let be the covariance of the estimated value at time k.

[0103] The median average filtering algorithm evaluates the n optimal estimates x after noise reduction. k|k The process involves first sorting the n data points from smallest to largest, then removing the minimum values ​​(m1) and maximum values ​​(m2), and finally averaging the n-m1-m2 optimal estimates.

[0104]

[0105] Where M represents the final weighing result of the seedling tray.

[0106] In summary, the variable-speed weighing device of this invention mounts the variable-speed drive device, positioning device, and control system on the frame, separating the weighing device from the frame. This allows the seedling trays to be dynamically transported above the frame by the variable-speed drive device, and statically weighed above the weighing device. Furthermore, because the weighing device is separated from the frame, the influence of mechanical vibration of the frame on the weighing accuracy is eliminated, resulting in more accurate weighing results. Moreover, the variable-speed weighing device of this invention employs a through-beam photoelectric sensor as the positioning device, a PLC as the control system, and an electromagnetic force load cell as the load cell, further improving the accuracy and stability of the weighing and increasing the confidence level of the weighing data.

[0107] The variable speed weighing method in this invention uses a variable speed drive device to enable the seedling trays to be transported at different speeds on the frame. When weighing at rest, a certain distance is maintained between the seedling trays in front and behind, so that the seedling trays in front and behind do not mechanically interfere with the seedling trays being weighed at rest on the weighing device. This makes the weighing results more accurate and reliable. After the weighing is completed, each seedling tray on the frame continues to move forward continuously, realizing automated and rapid weighing, which greatly improves the weighing efficiency and thus improves the production efficiency.

[0108] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for weighing the amount of rice seedlings in a rice seedling tray using variable speed, characterized in that: A variable-speed weighing device for rice seedling tray seeding is adopted; The device includes a frame, a weighing device, a speed-changing drive device, a positioning device, and a control system. The speed-changing weighing device is used to weigh the seeding amount in the seedling tray. The device is characterized in that the frame is arranged across the front and rear directions, and the speed-changing drive device, the positioning device, and the control system are all installed on the frame. The variable speed drive device is used to drive the seedling tray to perform variable speed movement from back to front, and includes a front drive assembly, a variable speed drive assembly and a rear drive assembly arranged sequentially from front to back on the frame. The weighing device is located below the transmission drive assembly and is separate from the frame. It includes a support frame, a base plate, a weighing sensor, a load-bearing frame and a mudguard arranged from bottom to top. Support wheel sets are provided on the front and rear sides of the load-bearing frame, and the two sets of support wheel sets are located at the intervals between the rear drive assembly, the transmission drive assembly and the front drive assembly, respectively. Both the front drive assembly and the rear drive assembly include multiple sets of spaced rubber drive wheels. The transmission drive assembly includes a front drive wheel and a rear drive wheel. The tops of the rubber drive wheels, the front drive wheel, and the rear drive wheel are flush with each other and lower than the top of the support wheel set. The front drive wheel and the rear drive wheel have the same radius, while the radius of the rubber drive wheel is smaller than that of the front drive wheel and the rear drive wheel. The axis of the front drive wheel and the rear drive wheel is lower than that of the rubber drive wheel. The rubber drive wheel, the front drive wheel, and the rear drive wheel rotate at the same speed. The linear velocity of the rubber drive wheel is V0, and the linear velocity of the front drive wheel and the rear drive wheel is V1, where V1 is greater than V0. There is a height difference ΔZ1 between the transmission drive unit and the top of the support wheel assembly; There is a height difference ΔZ2 between the axle of the front drive wheel, the axle of the rear drive wheel and the axle of the rubber drive wheel; The support wheel assembly includes a front support wheel and a rear support wheel located at the front and rear sides of the load-bearing frame; The front support wheel is located in the gap between the front drive assembly and the transmission drive assembly, and the rear support wheel is located in the gap between the transmission drive assembly and the rear drive assembly. The positioning device includes a through-beam photoelectric sensor emitter, a through-beam photoelectric sensor receiver, and a mounting plate; the through-beam photoelectric sensor emitter and the through-beam photoelectric sensor receiver are both fixed above the frame by the mounting plate and are located on the left and right sides of the front support wheel; the positioning device is used to identify whether the seedling tray has reached the weighing position. The control system is electrically connected to the weighing sensor and positioning device; The control system includes a pulse signal receiving unit, a data acquisition unit, a data processing unit, a human-machine interaction unit, and a power supply unit; the data acquisition unit includes a digital transmitter. The methods include: S1: Turn on the variable speed weighing device and place the seedling trays to be weighed onto the rear drive assembly in sequence. S2: The rear drive assembly drives the seedling tray to be weighed to start moving at a speed of V0; S3: When the seedling tray to be weighed moves to the rear support wheel, the front end of the seedling tray to be weighed begins to contact the rear support wheel and climbs up along the rear support wheel. After the center of mass passes the rear support wheel, the rear end of the seedling tray to be weighed separates from the rear drive assembly, and the front end contacts the front drive wheel. S4: The front drive wheel drives the seedling tray to be weighed to move at a speed of V1. At this time, the distance between the seedling tray to be weighed and another seedling tray to be weighed located behind it increases. Until the front end of the seedling tray to be weighed contacts the front support wheel and begins to climb upwards by inertia, after the front end of the seedling tray to be weighed climbs onto the front support wheel, it comes to a brief stop on the support wheel assembly under the action of friction. At this time, the next seedling tray to be weighed continues to move forward, and the distance between it and the seedling tray that is stationary on the support wheel assembly is reduced. The positioning device detects that the seedling tray to be weighed has reached the preset weighing position and transmits a pulse signal to the control system. After the pulse signal receiving unit receives the pulse signal, the control system controls the weighing sensor to start weighing the seedling tray that is stationary on the support wheel assembly. The weighing sensor outputs the obtained weighing data to the control system in the form of an analog signal. S5: When the next seedling tray to be weighed touches the seedling tray that is stationary on the support wheel group, the next seedling tray to be weighed pushes the seedling tray on the support wheel group to move forward. At this time, one weighing is completed. The data acquisition unit obtains an analog signal from the weighing sensor. After the weighing is completed, the seedling tray continues to move forward. When the rear end of the seedling tray falls from the rear support wheel to the rear drive wheel, the rear drive wheel drives the seedling tray to move forward at a speed of V1. S6: After weighing, the seedling tray continues to move forward under the drive of the speed change drive assembly. At this time, the distance between the weighed seedling tray and the next seedling tray to be weighed increases until the center of mass of the weighed seedling tray passes through the front support wheel. At this time, the rear end of the weighed seedling tray separates from the speed change drive assembly, and the front end begins to contact the front drive assembly. The front drive assembly begins to drive the weighed seedling tray to continue moving forward. S7: Repeat steps S2 to S6 for the next seedling tray to be weighed until the second to last seedling tray to be weighed is finished; S8: The last seedling tray to be weighed is weighed by human intervention.

2. The method for variable-speed weighing of rice seedling tray sowing amount according to claim 1, characterized in that: In step S4, when the seedling tray reaches the detection position, i.e. the seedling tray weighing position, the light beam emitted by the light emitter of the through-beam photoelectric sensor is blocked by the seedling tray, and the receiver of the through-beam photoelectric sensor cannot receive the light beam. At this time, the output signal of the through-beam photoelectric sensor receiver changes from low level to high level, and the pulse signal receiving unit of the control system receives a rising edge signal, i.e., a pulse signal, indicating that the seedling tray has reached the weighing position. The data acquisition unit starts to receive and read the analog signal from the weighing sensor. The digital transmitter amplifies the analog signal output by the weighing sensor and converts it into a digital signal, which is then transmitted to the data processing unit.

3. The method for weighing the amount of rice seedlings in a rice seedling tray according to claim 2, characterized in that: The data processing unit first extracts relatively stable weighing data from the digital signal to obtain a set of real measurement value datasets. Then, it performs noise reduction processing on the collected weighing data using a scalar Kalman filter algorithm to obtain an optimized dataset. Finally, it processes the optimized dataset using a median average filter algorithm to obtain the final weighing result of the seedling tray quality.

4. The method for weighing the amount of rice seedlings in a rice seedling tray according to claim 3, characterized in that: The scalar Kalman filter algorithm consists of two processes: prediction and update. The prediction process uses the estimate of the previous state to make an estimate of the current state. The update process uses the observations of the current state to optimize the predicted value obtained in the prediction stage, thereby obtaining a more accurate optimal estimate x. k|k : Prediction equation: Update equation: Where, x k|k-1 The current state result predicted using the optimal estimate at time k-1; x k-1|k-1 The optimal estimate at time k-1; u k p is the control gain for the current state. k-1|k-1 p is the covariance of the estimated values ​​at time k-1; k|k-1 The current covariance result is predicted using the covariance at time k-1; a is the state transition coefficient; b is the input gain coefficient; q is the excitation noise; h is the measurement coefficient; r is the measurement noise; g k The optimal Kalman gain at time k; z k x is a true measurement value at time k, i.e., the dataset of true measurement values; k|k p represents the optimal estimate at time k, i.e., the optimized dataset; k|k Let be the covariance of the estimated value at time k.

5. The method for weighing the amount of rice seedlings in a rice seedling tray according to claim 4, characterized in that: The median average filtering algorithm evaluates the n optimal estimates x after noise reduction. k|k The process involves first sorting the n data points from smallest to largest, then removing the minimum values ​​(m1) and maximum values ​​(m2), and finally averaging the n-m1-m2 optimal estimates. Where M represents the final weighing result of the seedling tray.

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