Method and system for accurately controlling fertilization flow of economic forest tree seed water and fertilizer all-in-one machine

Abstract

The invention relates to the technical field of agricultural fertilization control, in particular to an accurate fertilization flow control method and system for a water and fertilizer all-in-one machine for economic forest tree species, and the method comprises the steps: collecting water and fertilizer pressure data and water and fertilizer flow data in a water and fertilizer mixing pipeline in real time at a fertilization nozzle of each tree; analyzing the fluctuation condition of the water and fertilizer flow data of each tree within a preset duration before each collection moment, and determining the fluctuation trend influence coefficient of each tree at each collection moment; determining an upstream trend influence coefficient and a water and fertilizer flow deviation degree of each tree at each collection moment; determining the same-row fluctuation difference value of each tree at each collection moment; determining a proportionality coefficient adjustment value of each tree at each collection moment; and determining proportional parameters of a PID control algorithm, and controlling the fertilization flow of each tree. The invention aims to improve the control precision of the fertilization flow of each tree.

Description

Technical Field

[0001] The present application relates to the technical field of agricultural fertilization control, and specifically to a method and system for accurately controlling the fertilization flow rate of an integrated water-fertilizer machine for economic forest tree species. Background Art

[0002] The all-in-one water-fertilizer machine for economic forest tree species is a new type of intelligent agricultural equipment that integrates functions such as water-fertilizer ratio, mixing, transportation and spraying. It can mix water and fertilizer into water-fertilizer according to the growth characteristics and fertilizer requirements of different economic forest tree species, and realize directional, quantitative and timed irrigation and fertilization for various tree species in the planting field to meet the water and nutrition needs of different tree species.

[0003] In order to achieve more accurate fertilization for each tree in the planting field of economic forest tree species, an electric valve is usually installed at the fertilizer nozzle of each tree, and the control technology is used to control the fertilizer flow of the fertilizer nozzle. The proportional term parameters in the traditional PID control algorithm are usually fixed values ​​selected manually based on experience. However, due to the complexity of the spatial distribution of the water-fertilizer mixing pipeline in the planting field and the instability of the water pressure in the water-fertilizer mixing pipeline, the water and fertilizer flow at the fertilizer nozzle changes, so the traditional PID control algorithm cannot effectively control the fertilizer flow of each tree. Summary of the invention

[0004] In view of the above, it is necessary to provide a method and system for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species. Compared with the traditional method for controlling the fertilization flow rate of an integrated water and fertilizer machine, the control accuracy of the fertilization flow rate of each tree is improved:

[0005] In a first aspect, an embodiment of the present application provides a method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species, the method comprising the following steps:

[0006] At the fertilizer nozzle of each tree, the water and fertilizer pressure data and water and fertilizer flow data in the water and fertilizer mixing pipeline are collected in real time and recorded as the water and fertilizer pressure data and water and fertilizer flow data of each tree;

[0007] Analyze the fluctuation of water and fertilizer flow data of each tree within the preset time before each collection time, and determine the fluctuation trend influence coefficient of each tree at each collection time;

[0008] Obtain the trees upstream of the water-fertilizer mixing pipeline where each tree is located, analyze the distance between each tree and its upstream trees, and the change of water-fertilizer flow data of each upstream tree within a preset time before each collection time, and determine the upstream trend influence coefficient of each tree at each collection time;

[0009] Analyze the distribution of water and fertilizer flow data of each tree within a preset time before each collection time, and determine the water and fertilizer flow deviation of each tree at each collection time by combining the fluctuation trend influence coefficient, the upstream trend influence coefficient and the preset water and fertilizer flow value required by each tree;

[0010] Analyze the difference in the degree of dispersion of water and fertilizer pressure data between each tree and the trees in the same row within a preset time before each collection moment, and determine the fluctuation difference value of each tree in the same row at each collection moment;

[0011] Comprehensively analyzing the water and fertilizer flow deviation and the same-row fluctuation difference value, as well as the discrete degree of each tree, to determine the proportional coefficient adjustment value of each tree at each collection time;

[0012] Based on the proportional coefficient adjustment value, the proportional term parameter of the PID control algorithm is determined to control the fertilizer flow rate of each tree.

[0013] In one embodiment, the process of determining the fluctuation trend influence coefficient is as follows:

[0014] Arrange the water and fertilizer flow data of each tree within a preset time period before each collection time in time sequence to form a water and fertilizer flow sequence of each tree at each collection time;

[0015] The discrete degree of each preset number of consecutive adjacent data in each water and fertilizer flow sequence is recorded as the flow discrete degree;

[0016] Arrange all the flow discreteness corresponding to each tree at each collection time in time sequence to form a flow discreteness sequence of each tree at each collection time, and obtain a fitting straight line for all data in each flow discreteness sequence;

[0017] The fluctuation trend influence coefficient is positively correlated with the slope of the fitting straight line.

[0018] In one embodiment, the upstream trend influence coefficient is determined as follows:

[0019] Obtain the fitting straight line of all data in the water and fertilizer flow series of each upstream tree of each tree, and record it as the flow fitting straight line;

[0020] The upstream trend influence coefficient is positively correlated with the slope of the flow fitting curve, and negatively correlated with the distance.

[0021] In one embodiment, the process of determining the water and fertilizer flow deviation is as follows:

[0022] Calculate the mean of all data in each water and fertilizer flow series;

[0023] Determine the actual water and fertilizer flow value of each tree at each collection time by combining the mean value, the upstream trend influence coefficient and the fluctuation trend influence coefficient;

[0024] The water-fertilizer flow deviation is the difference between the actual water-fertilizer flow value and the preset water-fertilizer flow value.

[0025] In one embodiment, the actual water and fertilizer flow value is determined as follows:

[0026] Calculating the ratio of the upstream trend influence coefficient to the fluctuation trend influence coefficient;

[0027] The actual water and fertilizer flow value is the product of the mean value and the ratio.

[0028] In one embodiment, the process of determining the same-row fluctuation difference value is as follows:

[0029] The degree of dispersion of water and fertilizer pressure data of each tree within a preset time before each collection moment is recorded as the degree of pressure dispersion;

[0030] The difference in the degree of pressure dispersion between each tree and the trees in the same row is recorded as dispersion difference;

[0031] The same-row fluctuation difference value is the mean value of all the discrete differences corresponding to each tree.

[0032] In one embodiment, the process of determining the proportional coefficient adjustment value is as follows:

[0033] Calculate the fusion result of the pressure dispersion degree and the same-row fluctuation difference value;

[0034] The proportional coefficient adjustment value is positively correlated with the water and fertilizer flow deviation, and negatively correlated with the fusion result.

[0035] In one embodiment, the expression of the proportional coefficient adjustment value is:

[0036] Where P i,j,t represents the i-th row and j-th column tree W i,j The proportional coefficient adjustment value at the tth acquisition moment; F i,j,t ,y i,j,t , C i,j,t Represents the tree W i,j The water and fertilizer flow deviation at the tth collection moment, the pressure dispersion degree, and the same-row fluctuation difference value; P1 and P2 both represent constants preset to be greater than 0; β is a value preset to be greater than 0; norm() is a normalization function.

[0037] In one embodiment, the process of determining the proportional term parameter of the PID control algorithm to control the fertilizer flow rate of each tree is:

[0038] The proportional coefficient adjustment value is used as the proportional term parameter of the PID control algorithm in the PID controller of each tree at each collection time. The PID controller is used to control the opening of the electric valve at the fertilizer nozzle of each tree, and the fertilizer flow of each tree is controlled by the opening.

[0039] In the second aspect, an embodiment of the present application also provides a precise control system for the fertilizer flow rate of an integrated water-fertilizer machine for economic forest tree species, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned methods for precisely controlling the fertilizer flow rate of an integrated water-fertilizer machine for economic forest tree species are implemented.

[0040] This application has at least the following beneficial effects:

[0041] The present application analyzes the fluctuation characteristics of the water and fertilizer flow in the water and fertilizer mixing pipe at the fertilization nozzle of each tree, and determines the fluctuation trend influence coefficient and the upstream trend influence coefficient in combination with the influence of the water and fertilizer flow upstream of the water and fertilizer mixing pipe on the downstream water and fertilizer flow, and then obtains the water and fertilizer flow deviation, which can more accurately evaluate the degree of deviation of the water and fertilizer flow in the water and fertilizer mixing pipe at the fertilization nozzle of each tree from the preset water and fertilizer flow, so that when the fertilization flow of the tree is subsequently controlled, the fertilization flow deviation can be responded to more quickly;

[0042] Furthermore, by analyzing the proximity of the water pressure in the water-fertilizer mixing pipe at the fertilization nozzles of the same row of trees in the planting field, and the influence of the opening of the electric valve on the water pressure, the fluctuation difference value of the same row is determined, which can more accurately assess whether the fluctuation of water pressure is caused by the opening adjustment of the electric valve. Then, in the subsequent control process of the fertilization flow, the influence of the water pressure fluctuation caused by the opening adjustment of the electric valve on the fluctuation of the water and fertilizer flow can be reduced, so as to improve the control accuracy of the fertilization flow of the trees;

[0043] Furthermore, a proportional coefficient adjustment value is determined, and a proportional term parameter in a PID control algorithm in a PID controller is adaptively adjusted according to the proportional coefficient adjustment value. The PID controller is used to adjust the opening of the electric valve at the fertilizer nozzle. The fertilizer flow rate of each tree is controlled by the opening. This can better adapt to the flow characteristics of water and fertilizer in the water-fertilizer mixing pipeline at the fertilizer nozzle of each tree, thereby improving the control accuracy of the fertilizer flow rate of each tree. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 A flowchart of a method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species provided in one embodiment of the present application;

[0046] Figure 2 This is a schematic diagram of the fertilization scene of the water-fertilizer integrated machine;

[0047] Figure 3 Schematic diagram of the process of obtaining the fluctuation trend influence coefficient. DETAILED DESCRIPTION

[0048] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" and the like are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "or", "for example" and the like is intended to present related concepts in a concrete manner.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the present application. The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be understood that, unless otherwise specified, " / " means or.

[0050] It should also be noted that the terms "first" and "second" in the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0051] The following is a detailed description of the specific scheme of a method and system for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species provided by the present application, in conjunction with the accompanying drawings.

[0052] See also Figure 1 , which shows a flowchart of a method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species provided by an embodiment of the present application, the method comprising the following steps:

[0053] Step 1: Collect the water and fertilizer pressure data and water and fertilizer flow data in the water and fertilizer mixing pipeline in real time at the fertilizer nozzle of each tree.

[0054] Taking the planting field of any economic forest tree species as an example, at the fertilizer nozzle of each tree, use pressure sensors and liquid flow sensors to collect water and fertilizer pressure data and water and fertilizer flow data in the water and fertilizer mixing pipeline in real time, and record them as water and fertilizer pressure data and water and fertilizer flow data of each tree. And use pressure sensors and liquid flow sensors to collect water and fertilizer pressure data and water and fertilizer flow data in the water and fertilizer mixing main pipeline in real time. The schematic diagram of the fertilization scene of the water and fertilizer integrated machine is as follows Figure 2 As shown, Figure 2 1 indicates a pool, 2 indicates a filter tank, 3 indicates a water-fertilizer machine, 4 indicates a fertilizer tank, 5 indicates an electric valve, 6 indicates a water-fertilizer mixing main pipeline, 7 indicates a fertilizer nozzle with an electric valve, 8 indicates a water-fertilizer mixing pipeline, Figure 2 The row of trees parallel to the main water-fertilizer mixing pipe is the same row of trees, and the row of trees perpendicular to the main water-fertilizer mixing pipe is the same column of trees.

[0055] In this embodiment, when collecting water and fertilizer pressure data and water and fertilizer flow data, the sampling frequency is 20 Hz. The value of the sampling frequency is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0056] In the process of fertilizing the trees in the planting field, taking the tth collection moment as an example, the water and fertilizer pressure data and water and fertilizer flow data of each tree in the preset time interval before the tth collection moment are obtained respectively; and the water and fertilizer pressure data and water and fertilizer flow data in the water and fertilizer mixing main pipeline in the preset time interval before the tth collection moment are obtained. The preset time interval is adjacent to the tth collection moment. In addition, the preset water and fertilizer flow value required for each tree is obtained, and the preset water and fertilizer flow value needs to be determined according to the growth environment and tree species of the tree.

[0057] In this embodiment, the length of the preset time interval is 2 seconds. The value of the length of the preset time interval is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0058] In order to avoid the influence of data dimension on subsequent data processing, all water and fertilizer pressure data, water and fertilizer flow data, and preset water and fertilizer flow values ​​obtained are normalized respectively, and all water and fertilizer pressure data and all water and fertilizer flow data of each tree after normalization are arranged in time series to form the water and fertilizer pressure sequence and water and fertilizer flow sequence of each tree at the tth collection time; all water and fertilizer pressure data and all water and fertilizer flow data in the water and fertilizer mixing main pipeline after normalization are arranged in time series to form the water and fertilizer pressure sequence and water and fertilizer flow sequence of the water and fertilizer mixing main pipeline at the tth collection time.

[0059] In this embodiment, the Min-Max normalization method is used to normalize the water and fertilizer pressure data, the water and fertilizer flow data, and the preset water and fertilizer flow value. As other implementation methods, on the basis of being able to realize the normalization of the water and fertilizer pressure data, the water and fertilizer flow data, and the preset water and fertilizer flow value, the implementer can adopt other existing technologies, such as decimal calibration normalization method, Sigmoid function, etc., and this application does not make any special restrictions.

[0060] Step 2: within a preset time interval before each collection moment, comprehensively analyze the water-fertilizer flow data and water-fertilizer pressure data in the water-fertilizer mixing pipeline to determine the proportional coefficient adjustment value of each tree at each collection moment.

[0061] When using a PID controller to control the fertilizer flow of a tree fertilizer nozzle, the greater the deviation of the actual water and fertilizer flow value in the water-fertilizer mixing pipe at the tree fertilizer nozzle from the preset water and fertilizer flow value, the greater the degree of adjustment of the opening of the electric valve at the fertilizer nozzle needs to be. Therefore, it is necessary to adjust the proportional term parameters in the PID controller to increase the response speed of the electric valve to the fertilizer flow error, and then adjust the fertilizer flow of the fertilizer nozzle in time.

[0062] Step 2.1, analyze the fluctuation of water and fertilizer flow data of each tree within a preset time period before each collection time, and determine the fluctuation trend influence coefficient of each tree at each collection time.

[0063] In the process of fertilizing trees in the planting field, chemical deposits may be generated due to the alkalinity of the water source and the chemical reaction between fertilizers. These deposits will be deposited in the pipes, causing blockages; or the rust formed by the rust of the pipes will block the pipes, affecting the flow of water and fertilizers; or because the impurity particles in the water source are not completely filtered, the flow of liquid in the water-fertilizer mixing pipe is blocked, which in turn causes the water flow in the water-fertilizer mixing pipe to fluctuate. When the water flow fluctuation in the water-fertilizer mixing pipe increases, the water flow fluctuation causes the water flow to be unstable, and the unstable water flow hinders the flow in the pipe, which in turn causes a decrease in water flow.

[0064] Based on the above analysis, the tree W in the i-th row and j-th column in the planting field is i,j For example, for tree W i,j The water and fertilizer flow sequence A at the tth collection time i,j,t , calculate the water and fertilizer flow sequence A i,j,t The discrete degree of each preset number of consecutive adjacent data in is recorded as the flow discrete degree, and the tree W i,j All the traffic discrete degrees corresponding to the tth collection time are arranged in time sequence to form a tree W i,j The discrete sequence of traffic at the tth collection time. The discrete sequence of traffic is used to characterize the tree W i,jThe fluctuation of the water and fertilizer flow in the water and fertilizer mixing pipe at the fertilization nozzle during the historical time period at the tth collection moment.

[0065] In this embodiment, the value of the preset number is 5. The value of the preset number is preset by humans and can be set by the implementer. This application does not impose any special restrictions. i,j,t Each data in is the first element of the window, and a window of size 1×5 is constructed respectively, and the discrete degree of the 5 data in each window is calculated. When there is insufficient data in the window, no calculation is performed.

[0066] In this embodiment, the degree of dispersion is the standard deviation. As other implementation methods, on the basis of being able to measure the uneven distribution of the preset number of data, the implementer may use other existing technologies for measurement, such as variance, coefficient of variation, etc., and the application does not make special restrictions.

[0067] Obtain a fitting straight line for all data in the flow discrete sequence, use the slope of the fitting straight line as the exponent of an exponential function with a natural constant as the base, and use the calculation result of the exponential function as the tree W i,j The fluctuation trend influence coefficient at the tth acquisition moment. The purpose of the exponential function is to map all slopes to positive numbers.

[0068] In this embodiment, the least squares method is used to obtain the fitting straight line. The least squares method is a well-known technology and will not be described in detail in this application. As other implementation methods, on the basis of obtaining the fitting straight line of all data in the flow discrete sequence, the implementer can use other existing technologies to obtain the fitting straight line, such as linear regression analysis, weighted least squares method, etc., and this application does not make any special restrictions.

[0069] It should be noted that the fluctuation trend influence coefficient is used to evaluate the i,j The influence of water flow fluctuation in the water-fertilizer mixing pipe on the water-fertilizer flow rate at the fertilization nozzle is shown in Figure 1. In the historical time period at the t-th collection time, if the water flow fluctuation has an increasing trend, that is, the calculation result of the exponential function is larger, the water flow will be hindered more when flowing in the pipe, and the water-fertilizer flow rate is more likely to show a downward trend at the t-th collection time, that is, the greater the fluctuation trend influence coefficient. The schematic diagram of the acquisition process of the fluctuation trend influence coefficient is shown in Figure 1. Figure 3 shown.

[0070] Step 2.2, obtain the trees upstream of the water-fertilizer mixing pipeline where each tree is located, analyze the distance between each tree and its upstream trees, and the changes in the water-fertilizer flow data of each upstream tree within a preset time before each collection time, and determine the upstream trend influence coefficient of each tree at each collection time.

[0071] Secondly, when fertilizing trees in the same row in a planting field, the water-fertilizer mixing pipes used by the trees in the same row are usually connected, so the water-fertilizer flow at a certain point in the water-fertilizer mixing pipe is usually affected by the change of the water-fertilizer flow in the upstream pipe at that point.

[0072] Based on the above analysis, we still use tree W i,j For example, all trees with row numbers less than i and column numbers equal to j in the planting field are considered to be in tree W. i,j The tree is located upstream of the water-fertilizer mixing pipe.

[0073] In the tree W i,j Upstream tree W i-1,j For example, for tree W i-1,j In the water and fertilizer flow sequence at the t-th collection moment, a fitting straight line of all data in the water and fertilizer flow sequence is obtained, which is recorded as a flow fitting straight line. If i is 1, the flow fitting straight line is obtained for the water and fertilizer flow sequence of the water and fertilizer mixing main pipeline.

[0074] Furthermore, the distance between each tree and its upstream trees, as well as the slope of the flow fitting line of each upstream tree, are analyzed to determine the upstream trend influence coefficient of each tree at each collection time, which is used to characterize the influence of the change trend of the water and fertilizer flow in the water and fertilizer mixing pipe on the water and fertilizer flow at the fertilizer nozzle of each tree. The expression is:

[0075] In the formula, represents the i-th row and j-th column tree W i,j The upstream trend influence coefficient at the tth collection time; i represents the tree W i,j The number of rows; norm() represents the normalization function; d g,i Representation tree W i,j The number of rows and tree W g,j The reciprocal of the difference in the number of rows; exp() represents an exponential function with a natural constant as the base; k g,j,t Represents the slope of the flow fitting straight line of the tree in the g-th row and j-th column.

[0076] In this embodiment, the Softmax function is used to g,i Normalization is performed, as another implementation method, in which d g,i On the basis of normalization processing, the implementer may adopt other existing technologies, such as decimal calibration normalization method, Sigmoid function, etc., and this application does not impose any special restrictions.

[0077] It should be noted that: in the historical time period of the tth collection time, in the tree W g,j The greater the possibility that the water and fertilizer flow rate in the water and fertilizer mixing pipe will increase at the fertilization nozzle, that is, exp(kg,j,t ) is larger, and the tree W g,j With Tree W i,j The smaller the distance between them, that is, norm(d g,i ) is larger, the larger the tree W i,j At the fertilization nozzle, the water and fertilizer flow in the water and fertilizer mixing pipe is more likely to increase at the tth collection time, that is, the upstream trend influence coefficient The bigger.

[0078] Step 2.3, analyze the distribution of water and fertilizer flow data of each tree within a preset time period before each collection time, and determine the water and fertilizer flow deviation of each tree at each collection time by combining the fluctuation trend influence coefficient, the upstream trend influence coefficient and the preset water and fertilizer flow value required for each tree.

[0079] Furthermore, the distribution of data in the water and fertilizer flow sequence of each tree at each collection time is analyzed, and the water and fertilizer flow deviation of each tree at each collection time is determined by combining the fluctuation trend influence coefficient, the upstream trend influence coefficient and the preset water and fertilizer flow value, which is used to characterize the degree to which the water and fertilizer flow in the water and fertilizer mixing pipe at the fertilizer nozzle of each tree deviates from the preset water and fertilizer flow. The expression is:

[0080] In the formula, F i,j,t represents the i-th row and j-th column tree W i,j The water and fertilizer flow deviation at the tth collection moment; Representation tree W i,j The mean of all data in the water and fertilizer flow series at the tth collection moment; Represents the tree W i,j The fluctuation trend influence coefficient and upstream trend influence coefficient at the tth collection moment; a i,j Representation tree W i,j The preset water and fertilizer flow value. Let it be tree W i,j The actual water and fertilizer flow value at the tth collection moment.

[0081] It should be noted that: in the historical time period of the tth collection time, in the tree W i,j At the fertilization nozzle, the water flow fluctuation in the water-fertilizer mixing pipe tends to increase. The larger the size, and the smaller the tree W i,j The water and fertilizer flow in the upstream water and fertilizer mixing pipe has a downward trend at the tth collection time. i,j At the fertilization nozzle, the water and fertilizer flow in the water and fertilizer mixing pipe is smaller at the tth collection time, that is, The smaller the tree W i,jThe greater the difference between the actual water and fertilizer flow value at the tth collection time and the preset water and fertilizer flow value, the greater the difference between the actual water and fertilizer flow value at the tth collection time and the preset water and fertilizer flow value. i,j At the fertilizer nozzle, the more the water and fertilizer flow in the water and fertilizer mixing pipe deviates from the preset water and fertilizer flow value at the tth collection time, that is, the greater the value of the water and fertilizer flow deviation.

[0082] Step 2.4, analyze the difference in the degree of dispersion of water and fertilizer pressure data between each tree and the trees in the same row within a preset time before each collection moment, and determine the fluctuation difference value of each tree in the same row at each collection moment.

[0083] Since the water pump is the power source of the integrated water and fertilizer machine, it is responsible for transporting the mixture of water and fertilizer to the entire irrigation system. When the integrated water and fertilizer machine for economic forest tree species is used to fertilize the trees in the planting field, the water pressure in the water and fertilizer mixing pipeline at the fertilizer nozzle of each tree is mainly related to the length of the pipeline from the water pump of the integrated water and fertilizer machine for economic forest tree species to the water and fertilizer mixing pipeline. Therefore, the water pressure in the water and fertilizer mixing pipeline at the fertilizer nozzle of the same row of trees in the planting field is usually close. When the water and fertilizer flow in the water and fertilizer mixing pipeline is controlled by adjusting the opening of the electric valve, it usually causes the water pressure in the water and fertilizer mixing pipeline to fluctuate, and the larger the opening adjustment range of the electric valve, the greater the degree of water pressure fluctuation, which will cause the water and fertilizer flow in the water and fertilizer mixing pipeline to fluctuate in the subsequent time period. Therefore, in order to improve the stability of the water pressure in the water and fertilizer mixing pipeline and reduce the influence of the water pressure fluctuation caused by the electric valve opening adjustment on the subsequent water and fertilizer flow fluctuation, when using the PID controller to control the opening of the electric valve, it is necessary to reduce the proportional coefficient in the PID controller.

[0084] Based on the above analysis, we still use tree W i,j For example, the calculation tree W i,j The discrete degree of all data in the water and fertilizer pressure sequence at the tth collection moment is recorded as the pressure discrete degree; i,j The difference in the degree of pressure dispersion between the trees in the same row is recorded as the dispersion difference; the mean of all the dispersion differences is taken as the tree W i,j The fluctuation difference value of the same row at the tth collection time.

[0085] In this embodiment, the degree of dispersion of all data in the water and fertilizer pressure sequence is the standard deviation. As other implementation methods, on the basis of being able to measure the degree of uneven distribution of all data in the water and fertilizer pressure sequence, the implementer can adopt other existing technologies, such as variance, coefficient of variation, etc., and this application does not impose any special restrictions.

[0086] It should be noted that: in the historical time period of the tth collection time, in the tree W i,jThe greater the difference in the fluctuation degree of water pressure in the water-fertilizer mixing pipe at the fertilization nozzle of the tree in the same row, that is, the greater the fluctuation difference value in the same row, the greater the fluctuation difference value in the tree W. i,j The reason for the water pressure fluctuation in the water-fertilizer mixing pipe at the fertilization nozzle is more likely to be: in the historical time period of the tth collection time, the tree W i,j This is caused by the opening adjustment of the electric valve at the fertilizer nozzle.

[0087] Step 2.5, comprehensively analyzing the water and fertilizer flow deviation and the same-row fluctuation difference value, as well as the discrete degree of each tree, to determine the proportional coefficient adjustment value of each tree at each collection time.

[0088] Furthermore, the water and fertilizer flow deviation and the same-row fluctuation difference value, as well as the pressure dispersion of each tree, are comprehensively analyzed to determine the proportional coefficient adjustment value of each tree at each collection time, which is used to characterize the value of the proportional term parameter of the PID control algorithm at each collection time when the PID controller is used to adjust the opening of the electric valve at the fertilizer nozzle of each tree. The expression is:

[0089] Where P i,j,t represents the i-th row and j-th column tree W i,j The proportional coefficient adjustment value at the tth acquisition moment; F i,j,t ,y i,j,t , C i,j,t Represents the tree W i,j The water and fertilizer flow deviation at the tth collection moment, the pressure dispersion degree, and the same-row fluctuation difference value; P1 and P2 both represent constants greater than 0. When P is satisfied i,j,t The value range of P1 and P2 is (0,1), and the implementer can set the values ​​of P1 and P2 by himself; β is a preset value greater than 0, the purpose of which is to prevent the denominator from being 0. The value of β can be set by the implementer. In this embodiment, the value of β is 0.01; norm() is a normalization function.

[0090] In this embodiment, in order to avoid the proportional term parameter being too large, resulting in unstable water and fertilizer flow, and to avoid the proportional term parameter being too small, resulting in too slow response of the PID controller to the water and fertilizer flow error, the values ​​of P1 and P2 are 0.6 and 0.3 respectively.

[0091] In this embodiment, the Min-Max normalization method is used to Normalization is performed, as another implementation method, in which On the basis of normalization processing, the implementer may adopt other existing technologies, such as decimal calibration normalization method, Sigmoid function, etc., and this application does not impose any special restrictions.

[0092] It should be noted that: in the tree Wi,j At the fertilization nozzle, the more the water and fertilizer flow in the water and fertilizer mixing pipe deviates from the preset water and fertilizer flow value at the tth collection time, that is, the greater the value of the water and fertilizer flow deviation, the more effective it is to improve the tree W i,j The response speed of the electric valve at the fertilization nozzle to the fertilization flow error is adjusted in time. i,j The larger the actual fertilizer flow rate, the larger the proportional term parameter of the PID control algorithm should be, that is, P i,j,t The larger the value, the larger the historical period of the tth collection time. i,j The greater the water pressure fluctuation in the water-fertilizer mixing pipe at the fertilization nozzle, the greater the water pressure fluctuation in the water-fertilizer mixing pipe, that is, y i,j,t The larger it is, the more likely it is due to tree W i,j Corresponding to the opening adjustment of the electric valve, that is, C i,j,t The larger the tree W is, the better. i,j The stability of the water pressure in the water-fertilizer mixing pipeline at the location is improved to reduce the influence of the water pressure fluctuation caused by the electric valve opening adjustment on the subsequent water-fertilizer flow fluctuation. The proportional term parameter of the PID controller algorithm should be smaller, that is, P i,j,t The smaller.

[0093] Follow the tree W i,j The proportional coefficient adjustment value at the t-th collection moment is obtained by the same acquisition method, and the proportional coefficient adjustment value of each tree at each collection moment is obtained.

[0094] Step 3: Based on the proportional coefficient adjustment value, determine the proportional term parameter of the PID control algorithm to control the fertilizer flow rate of each tree.

[0095] For the electric valve at the fertilizer nozzle of each tree, there is a controller for controlling the opening of the electric valve. The proportional coefficient adjustment value of each tree at each collection time is used as the proportional term parameter of the PID control algorithm in the PID controller of each tree at each collection time. The PID controller is used to control the opening of the electric valve at the fertilizer nozzle of each tree, and the fertilizer flow of each tree is controlled by the opening. In the process of controlling the fertilizer flow of trees in the planting field, if there is insufficient data and the proportional term parameter of the PID control algorithm cannot be calculated, no calculation is performed.

[0096] Based on the same inventive concept as the above method, an embodiment of the present application also provides a precise control system for the fertilizer flow of an integrated water-fertilizer machine for economic forest tree species, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned methods for precise control of the fertilizer flow of an integrated water-fertilizer machine for economic forest tree species.

[0097] In summary, the present application analyzes the fluctuation characteristics of the water and fertilizer flow in the water-fertilizer mixing pipe at the fertilization nozzle of each tree, and combines the influence of the water and fertilizer flow upstream of the water-fertilizer mixing pipe on the downstream water and fertilizer flow, determines the fluctuation trend influence coefficient and the upstream trend influence coefficient, and then obtains the water and fertilizer flow deviation, which can more accurately evaluate the degree of deviation of the water and fertilizer flow in the water-fertilizer mixing pipe at the fertilization nozzle of each tree from the preset water and fertilizer flow, so that when the fertilization flow of the tree is subsequently controlled, the fertilization flow deviation can be responded to more quickly;

[0098] Furthermore, by analyzing the proximity of the water pressure in the water-fertilizer mixing pipe at the fertilization nozzles of the same row of trees in the planting field, and the influence of the opening of the electric valve on the water pressure, the fluctuation difference value of the same row is determined, which can more accurately assess whether the fluctuation of water pressure is caused by the opening adjustment of the electric valve. Then, in the subsequent control process of the fertilization flow, the influence of the water pressure fluctuation caused by the opening adjustment of the electric valve on the fluctuation of the water and fertilizer flow can be reduced, so as to improve the control accuracy of the fertilization flow of the trees;

[0099] Furthermore, a proportional coefficient adjustment value is determined, and a proportional term parameter in a PID control algorithm in a PID controller is adaptively adjusted according to the proportional coefficient adjustment value. The PID controller is used to adjust the opening of the electric valve at the fertilizer nozzle. The fertilizer flow rate of each tree is controlled by the opening. This can better adapt to the flow characteristics of water and fertilizer in the water-fertilizer mixing pipeline at the fertilizer nozzle of each tree, thereby improving the control accuracy of the fertilizer flow rate of each tree.

[0100] The flowchart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to the embodiment of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowchart and the block diagram in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in a different order from the order disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0101] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic features of the present application. Therefore, no matter from which point of view, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. A method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species, characterized in that: The method comprises the following steps: At the fertilizer nozzle of each tree, the water and fertilizer pressure data and water and fertilizer flow data in the water and fertilizer mixing pipeline are collected in real time and recorded as the water and fertilizer pressure data and water and fertilizer flow data of each tree; Analyze the fluctuation of water and fertilizer flow data of each tree within the preset time before each collection time, and determine the fluctuation trend influence coefficient of each tree at each collection time; Obtain the trees upstream of the water-fertilizer mixing pipeline where each tree is located, analyze the distance between each tree and its upstream trees, and the change of water-fertilizer flow data of each upstream tree within a preset time before each collection time, and determine the upstream trend influence coefficient of each tree at each collection time; Analyze the distribution of water and fertilizer flow data of each tree within a preset time before each collection time, and determine the water and fertilizer flow deviation of each tree at each collection time by combining the fluctuation trend influence coefficient, the upstream trend influence coefficient and the preset water and fertilizer flow value required by each tree; Analyze the difference in the degree of dispersion of water and fertilizer pressure data between each tree and the trees in the same row within a preset time before each collection moment, and determine the fluctuation difference value of each tree in the same row at each collection moment; Comprehensively analyzing the water and fertilizer flow deviation and the same-row fluctuation difference value, as well as the discrete degree of each tree, to determine the proportional coefficient adjustment value of each tree at each collection time; Based on the proportional coefficient adjustment value, the proportional term parameter of the PID control algorithm is determined to control the fertilizer flow rate of each tree.

2. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species according to claim 1, characterized in that: The determination process of the fluctuation trend influence coefficient is as follows: Arrange the water and fertilizer flow data of each tree within a preset time period before each collection time in time sequence to form a water and fertilizer flow sequence of each tree at each collection time; The discrete degree of each preset number of consecutive adjacent data in each water and fertilizer flow sequence is recorded as the flow discrete degree; Arrange all the flow discreteness corresponding to each tree at each collection time in time sequence to form a flow discreteness sequence of each tree at each collection time, and obtain a fitting straight line for all data in each flow discreteness sequence; The fluctuation trend influence coefficient is positively correlated with the slope of the fitting straight line.

3. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species as claimed in claim 2, characterized in that: The determination process of the upstream trend influence coefficient is: Obtain the fitting straight line of all data in the water and fertilizer flow series of each upstream tree of each tree, and record it as the flow fitting straight line; The upstream trend influence coefficient is positively correlated with the slope of the flow fitting curve, and negatively correlated with the distance.

4. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species as claimed in claim 2, characterized in that: The process of determining the water and fertilizer flow deviation is as follows: Calculate the mean of all data in each water and fertilizer flow series; Determine the actual water and fertilizer flow value of each tree at each collection time by combining the mean value, the upstream trend influence coefficient and the fluctuation trend influence coefficient; The water-fertilizer flow deviation is the difference between the actual water-fertilizer flow value and the preset water-fertilizer flow value.

5. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species as claimed in claim 4, characterized in that: The actual water and fertilizer flow value is determined as follows: Calculating the ratio of the upstream trend influence coefficient to the fluctuation trend influence coefficient; The actual water and fertilizer flow value is the product of the mean value and the ratio.

6. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species according to claim 1, characterized in that: The process of determining the same-row fluctuation difference value is as follows: The degree of dispersion of water and fertilizer pressure data of each tree within a preset time before each collection moment is recorded as the degree of pressure dispersion; The difference in the degree of pressure dispersion between each tree and the trees in the same row is recorded as dispersion difference; The same-row fluctuation difference value is the mean value of all the discrete differences corresponding to each tree.

7. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species as claimed in claim 6, characterized in that: The process of determining the proportional coefficient adjustment value is as follows: Calculate the fusion result of the pressure dispersion degree and the same-row fluctuation difference value; The proportional coefficient adjustment value is positively correlated with the water and fertilizer flow deviation, and negatively correlated with the fusion result.

8. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species as claimed in claim 6, characterized in that: The expression of the proportional coefficient adjustment value is: Where P i,j,t Represents the i-th row and j-th column tree W i,j The proportional coefficient adjustment value at the tth acquisition moment; F i,j,t ,y i,j,t , C i,j,t Represents the tree W i,j The water and fertilizer flow deviation at the tth collection moment, the pressure dispersion degree, and the same-row fluctuation difference value; P1 and P2 both represent constants preset to be greater than 0; β is a value preset to be greater than 0; norm() is a normalization function.

9. The method for accurately controlling the fertilization flow rate of an integrated water and fertilizer machine for economic forest tree species according to claim 1, characterized in that: The process of determining the proportional term parameters of the PID control algorithm to control the fertilization flow rate of each tree is as follows: The proportional coefficient adjustment value is used as the proportional term parameter of the PID control algorithm in the PID controller of each tree at each collection time. The PID controller is used to control the opening of the electric valve at the fertilizer nozzle of each tree, and the fertilizer flow of each tree is controlled by the opening.

10. A precise control system for fertilizer flow rate of economic forest tree species water-fertilizer integrated machine, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method for accurately controlling the fertilization flow rate of an integrated water-fertilizer machine for economic forest tree species as described in any one of claims 1-9 are implemented.

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