Speed tracking prediction method for wheat seeding unit

Abstract

The invention discloses a speed tracking prediction method for a wheat seeding unit. The method comprises the following steps: 1, acquiring related speed data; 2, judging driving conditions (complete constant speed, complete variable speed, including constant speed and variable speed); 3, establishing and solving an error function; 4, calculating a speed tracking predicted value; and 5, judging and processing the abnormal condition of the speed measurement value. According to the invention, the collected running speed of the wheat seeding unit can be analyzed in real time, the running condition of the seeding unit is analyzed and judged, and the speed information of the running condition is analyzed and calculated based on the principle of the least square method, so that the speed value at the current moment is predicted, and the rotating speed of the seed / fertilizer shaft motor is controlled. Therefore, precise seed discharging / fertilizer discharging of the wheat seeder can be realized.

Description

Technical Field

[0001] The invention mainly relates to an agricultural machinery automation control technology, in particular to a speed tracking and prediction method for a wheat seeding machine group. Background Art

[0002] During operation, traditional wheat seeders are often affected by the complex field environment, which reduces the uniformity of seeding / fertilization, resulting in a significant impact on the quality of wheat seeding / fertilization. In order to achieve precision seeding / fertilization of wheat, some scholars have developed an intelligent wheat centralized control system, which obtains the seeding / fertilization speed of the seeding machine group through Beidou messages or radar speed measurement, and transmits the speed signal to the single-chip microcomputer, which sends the speed signal to the motor driver to achieve precision seeding / fertilization of the seeding wheel. However, due to the excitation of the complex road surface on the field ground, the vibration of the tractor and other factors that cause the vibration of the fuselage, as well as the influence of weather, buildings and other obstructions in the field, it is easy to cause the obtained seeding machine group driving speed to be abnormal or even zero, which will seriously affect the operation accuracy of the wheat precision seeder, and then affect the uniformity of wheat seeding / fertilization and the consistency of each row.

[0003] In recent years, some papers and patents have proposed various solutions and ideas for specific problems. However, most of these studies are based on the prediction of missing data points under the condition of uniform speed driving of wheat seeding machine, and do not fully consider the acceleration and deceleration conditions in the actual seeding process, especially when the predicted time is between the turning point of variable speed and uniform speed, which leads to low seeding / fertilizer efficiency and accuracy of wheat seeding machine. Summary of the invention

[0004] The present invention aims to solve the deficiencies of the above-mentioned prior art and proposes a speed tracking and prediction method for a wheat seeding machine group, in order to improve the problem of reduced seeding / fertilizer discharge accuracy caused by unstable speed measurement of the seeding machine in a complex field operation environment, thereby improving the accuracy of speed tracking and prediction of the seeding machine group and providing technical guarantee for intelligent electronically controlled wheat seeding.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme:

[0006] The speed tracking prediction method of a wheat seeding machine group of the present invention is characterized in that it comprises the following steps:

[0007] Step 1: Get the current k-th time t k The first n moments {t k-i |i=1,2,3…,n} the driving speed of the wheat seeding machine group ,in, represents the current k-th time t k The i-th moment before t k-iMeasured travel speed of wheat seeding group;

[0008] Step 2, determining the driving working condition of the wheat seeding machine group, including: a completely uniform speed working condition, a completely variable speed working condition, and a uniform speed working condition and a variable speed working condition;

[0009] Step 2.1: Use formula (1) to calculate the current k-th time t k The standard deviation of speed s k :

[0010] (1)

[0011] In formula (1), is the current k-th moment t k The average driving speed of the wheat seeding machine group in the first n moments;

[0012] Step 2.2: If , then it means that the wheat seeding machine group is at the current k-th moment t k In the completely uniform speed condition, Indicates the threshold value;

[0013] like , then it means that the wheat seeding machine group is at the current k-th moment t k In non-completely uniform speed conditions:

[0014] when When, it means that the wheat seeding machine group is at the current k-th moment t k In deceleration condition;

[0015] when When, it means that the wheat seeding machine group is at the current k-th moment t k In acceleration condition;

[0016] Use formula (2) to calculate the current k-th time t k The first t k-m The standard deviation of the velocity set after time :

[0017] (2)

[0018] when Meet the threshold ,and , then it means the current k-th moment t k The first t k-m Before the moment t, the wheat seeding machine group was in the acceleration state. k-m After the time, the wheat seeding unit enters the uniform speed condition;

[0019] Use formula (3) to calculate the current k-th time tk The front t k-m The standard deviation of the data before time :

[0020] (3)

[0021] when Meet the threshold ,and , then it means the current k-th moment t k The front t k-m Before the moment, the wheat seeding machine group was in a uniform speed condition. k-m After the time, the wheat seeding machine group enters the deceleration state;

[0022] Step 3: Use formula (4) to establish the error function , and based on the least squares principle, the error function Solve it and use formula (5) to get the optimal estimated value of the acceleration a under the speed change condition: , where a and b represent t k-n Time to t k-1 The acceleration and initial velocity of the wheat seeding machine group during the period between the times;

[0023] (4)

[0024] (5)

[0025] Step 4: Calculate the current k-th time t k The speed tracking prediction value v k ;

[0026] If the speed measurement set In a completely uniform speed condition, the average value of the speed at the n measured moments is taken as the current kth moment t k The speed tracking prediction value v k ;

[0027] If the speed measurement set The acceleration condition is in front and the uniform speed condition is in the back, then z k-m As the demarcation point, the speed tracking prediction value v of the current speed is obtained using formula (6) k :

[0028] (6)

[0029] If the wheat seeding machine group is judged to be in the fully variable speed condition, then the current k-th time t is obtained using formula (7): k Tracking prediction value of speed v k :

[0030] (7)

[0031] In formula (7), represents the k-1th time t k-1 The speed measurement value, represents the optimal estimate between adjacent moments;

[0032] Step 5: If , then it is considered that the wheat seeding machine group is at the current k-th moment t k The speed measurement value z k Exception, and v k Assign to z k Otherwise, z k remain unchanged; thus according to z k For the wheat seeding machine group at the current k-th time t k The speed of the seeding / fertilizing shaft motor is controlled by Indicates the threshold value.

[0033] An electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the speed tracking prediction method, and the processor is configured to execute the program stored in the memory.

[0034] The present invention provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program executes the steps of the speed tracking prediction method when the computer program is executed by a processor.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention is based on analyzing the speed information of the n moments before the current moment, fitting and solving the acceleration of the acceleration and deceleration driving conditions in the field based on the principle of least squares method, fully considering the operating conditions of the actual sowing process of the wheat sowing machine group, and solving the problem that the speed tracking and prediction system in the prior art cannot adapt to different operating conditions, especially the problem of low accuracy under the acceleration and deceleration driving conditions in the field.

[0037] 2. The present invention improves the prediction accuracy of the current speed, so that the seeder can more accurately adjust the amount of seeds and fertilizers according to the speed, thereby improving the sowing quality, reducing the uneven sowing phenomenon caused by speed fluctuations, ensuring the uniformity and accuracy of sowing, and providing better conditions for the growth of wheat. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the change of driving speed of a wheat seeder under various working conditions during sowing operation;

[0039] Figure 2 This is a flow chart for speed tracking and prediction of wheat intelligent precision seeding machine group;

[0040] Figure 3 This is an overall operation flow chart of the redundant system of the present invention. DETAILED DESCRIPTION

[0041] In the actual wheat sowing process, the sowing machine group usually accelerates first, then maintains a constant speed, and then decelerates during the sowing operation in each row. Therefore, in order to improve the accuracy of the speed tracking prediction of the sowing machine group and improve the seeding / fertilizer discharge accuracy of the wheat precision seeder, in this embodiment, a speed tracking and prediction method for the wheat sowing machine group is proposed. By analyzing and collecting the driving speed of the sowing machine group, the operating condition of the sowing machine group is analyzed and judged, and the speed information of the driving condition is analyzed and calculated based on the principle of least squares method, and then the speed value at the current moment is predicted, so that the precision seeding / fertilizer discharge of the wheat sowing machine can be realized, so as to improve the problem of reduced seeding / fertilizer discharge accuracy of the sowing machine due to unstable speed measurement in complex field operation environments, and provide technical guarantee for intelligent electronic control sowing of wheat. Specifically, if Figure 2 As shown, the following steps are included:

[0042] Step 1: Get the current k-th time t k The first n moments {t k-i |i=1,2,3…,n} the driving speed of the wheat seeding machine group , where the value of n needs to find a good compromise between system response speed, computational efficiency, statistical stability and system robustness; represents the current k-th time t k The i-th moment before t k-i Measured travel speed of the wheat seeding group.

[0043] Step 2: Figure 1 As shown in the figure, when carrying out wheat sowing operations, the sowing machine group first starts from the field and accelerates to a uniform speed sowing condition. When it reaches the field, the sowing machine group gradually slows down, turns around, and starts sowing in the next row. There are three possible data sets of the sowing machine group measurement speed obtained by the above process analysis, which can be used to judge the driving conditions of the wheat sowing machine group, including: completely uniform speed conditions, completely variable speed conditions, and both uniform speed conditions and variable speed conditions. By collecting historical speed data, we can better understand the changing trend of the operating status of the sowing machine group, so as to more accurately predict the speed at the current moment, adapt to different field operation conditions, improve the accuracy of the sowing machine group speed tracking prediction, and finally realize the precise seeding / fertilizer discharge of the wheat sowing machine, improve the sowing quality, and reduce the uneven sowing caused by speed fluctuations.

[0044] Step 2.1: During the operation of the wheat planter, the speed value of the uniform speed condition will fluctuate around the mean value of the condition, so the standard deviation of the data set for this condition is close to 0 km / h; while the speed value of the variable speed condition changes in one direction, so the standard deviation of the data set for this condition is significantly greater than that of the uniform speed condition, so a standard deviation threshold can be set. ;

[0045] like Figure 2 The figure below is used to judge the driving condition of the wheat seeding machine group. By comparing the speed standard deviation s k With threshold The value of and the change trend of the speed data can be used to determine whether the seeding machine group is in a completely uniform speed condition, a completely variable speed condition, or a combination of uniform speed and variable speed conditions. Using formula (1), calculate the current k-th moment t k The standard deviation of speed s k :

[0046] (1)

[0047] In formula (1), is the current k-th moment t k The average driving speed of the wheat planter group in the first n moments.

[0048] Step 2.2: If , then it means that the wheat seeding machine group is at the current k-th moment t k In the completely uniform speed condition, Indicates the threshold value;

[0049] like , then it means that the wheat seeding machine group is at the current k-th moment t k In non-completely uniform speed conditions:

[0050] when When, it means that the wheat seeding machine group is at the current k-th moment t k In deceleration condition;

[0051] when When, it means that the wheat seeding machine group is at the current k-th moment t k In acceleration condition;

[0052] Use formula (2) to calculate the current k-th time t k The first t k-m The standard deviation of the velocity set after time :

[0053] (2)

[0054] when Meet the threshold ,and , then it means the current k-th moment t k The first t k-m Before the moment t, the wheat seeding machine group was in the acceleration state. k-m After the time, the wheat seeding unit entered a uniform speed condition.

[0055] Use formula (3) to calculate the current k-th time t k The front t k-m The standard deviation of the data before time :

[0056] (3)

[0057] when Meet the threshold ,and , then it means the current k-th moment t k The front t k-m Before the moment, the wheat seeding machine group was in a uniform speed condition. k-m After the time, the wheat seeding unit enters the deceleration condition.

[0058] Step 3: Use formula (4) to establish the error function , and based on the least squares principle, the error function Solve it and use formula (5) to get the optimal estimated value of the acceleration a under the speed change condition: , where a and b represent t k-n Time to t k-1 The acceleration and initial velocity of the wheat seeding machine group during the period between the times;

[0059] (4)

[0060] (5)

[0061] Building the error function Different forms are given according to different working conditions because the wheat seeding unit has a variety of driving conditions when working in the field (complete speed change condition, acceleration condition first and constant speed condition second, constant speed condition first and deceleration condition first). The speed changes differently under different working conditions, so different expressions are needed to accurately describe the error between the actual speed measurement value and the speed value calculated based on the model.

[0062] The error function is solved based on the principle of least squares because the least squares method can find the optimal parameter value of the error function by minimizing the sum of squares of the errors. In this problem, the optimal estimated value of the acceleration a under variable speed conditions is to better describe the speed variation law of the seeding machine group under different working conditions, thereby more accurately controlling the amount of seeding and fertilizer discharge, improving the seeding quality, and reducing the uneven seeding phenomenon caused by inaccurate speed prediction.

[0063] Step 4: Calculate the current k-th time t k The speed tracking prediction value v k ;

[0064] If the speed measurement set In a completely uniform speed condition, the average value of the speed at the n measured moments is taken as the current kth moment t k The speed tracking prediction value v k ;

[0065] If the speed measurement set The acceleration condition is in front and the uniform speed condition is in the back, then z k-m As the dividing point, z k-m To z k-1 The average value of the speed at the moment is used as the speed tracking prediction value v of the current moment speed k , as shown in formula (6):

[0066] (6)

[0067] If the wheat seeding machine group is judged to be in the fully variable speed condition, then the current k-th moment t k The velocity measurement value at the previous moment Plus As the current k-th moment t k Tracking prediction value of speed v k , as shown in formula (7)

[0068] (7)

[0069] Step 5: Figure 3 As shown in the figure, considering the influence of driver's driving skills and field road surface, if , then it is considered that the wheat seeding machine group is at the current k-th moment t k The speed measurement value z k Exception, and v k Assign to z k Otherwise, z k remain unchanged; thus according to z k For the wheat seeding machine group at the current k-th time t k The speed of the seeding / fertilizing shaft motor is controlled. Indicates the threshold value. and This is to determine whether the speed measurement value is abnormal. When , it means that the actual measured value deviates greatly from the predicted value, and there may be problems such as inaccurate measurement. The purpose of assigning a value to is to correct the abnormal speed measurement value, so that the speed value used to control the speed of the seeding / fertilizing shaft motor is more accurate, avoiding problems such as uneven sowing or inaccurate fertilization due to abnormal speed measurement.

[0070] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0071] In this embodiment, a computer-readable storage medium stores a computer program on the computer-readable storage medium, and the computer program executes the steps of the above method when executed by a processor.

Claims

1. A speed tracking and prediction method for a wheat seeding machine group, characterized in that: The following steps are involved: Step 1: Get the current k-th time t k The first n moments {t k-i |i=1,2,3…,n} the driving speed of the wheat seeding machine group ,in, represents the current k-th time t k The i-th moment before t k-i Measured travel speed of wheat seeding group; Step 2, determining the driving working condition of the wheat seeding machine group, including: a completely uniform speed working condition, a completely variable speed working condition, and a uniform speed working condition and a variable speed working condition; Step 2.1: Use formula (1) to calculate the current k-th time t k The standard deviation of speed s k : (1) In formula (1), is the current k-th moment t k The average driving speed of the wheat seeding machine group in the first n moments; Step 2.2: If , then it means that the wheat seeding machine group is at the current k-th moment t k In the completely uniform speed condition, Indicates the threshold value; like , then it means that the wheat seeding machine group is at the current k-th moment t k In non-completely uniform speed conditions: when When, it means that the wheat seeding machine group is at the current k-th moment t k In deceleration condition; when When, it means that the wheat seeding machine group is at the current k-th moment t k In acceleration condition; Use formula (2) to calculate the current k-th time t k The first t k-m The standard deviation of the velocity set after time : (2) when Meet the threshold ,and , then it means the current k-th moment t k The first t k-m Before the moment t, the wheat seeding machine group was in the acceleration state. k-m After the time, the wheat seeding unit enters the uniform speed condition; Use formula (3) to calculate the current k-th time t k The front t k-m The standard deviation of the data before time : (3) when Meet the threshold ,and , then it means the current k-th moment t k The front t k-m Before the moment, the wheat seeding machine group was in a uniform speed condition. k-m After the time, the wheat seeding machine group enters the deceleration state; Step 3: Use formula (4) to establish the error function , and based on the least squares principle, the error function Solve it and use formula (5) to get the optimal estimated value of the acceleration a under the speed change condition: , where a and b represent t k-n Time to t k-1 The acceleration and initial velocity of the wheat seeding machine group during the period between the times; (4) (5) Step 4: Calculate the current k-th time t k The speed tracking prediction value v k ; If the speed measurement set In a completely uniform speed condition, the average value of the speed at the n measured moments is taken as the current kth moment t k The speed tracking prediction value v k ; If the speed measurement set The acceleration condition is in front and the uniform speed condition is in the back, then z k-m As the demarcation point, the speed tracking prediction value v of the current speed is obtained using formula (6) k : (6) If the wheat seeding machine group is judged to be in the fully variable speed condition, then the current k-th time t is obtained using formula (7): k Tracking prediction value of speed v k : (7) In formula (7), represents the k-1th time t k-1 The speed measurement value, represents the optimal estimate between adjacent moments; Step 5: If , then it is considered that the wheat seeding machine group is at the current k-th moment t k The speed measurement value z k Exception, and v k Assign to z k Otherwise, z k remain unchanged; thus according to z k For the wheat seeding machine group at the current k-th time t k The speed of the seeding / fertilizing shaft motor is controlled by Indicates the threshold value.

2. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the speed tracking prediction method according to claim 1, and the processor is configured to execute the program stored in the memory.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the speed tracking prediction method according to claim 1 are executed.

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