Transverse displacement fertilization control method based on canopy information perception

Abstract

The invention discloses a transverse displacement fertilization control method based on canopy information perception, and relates to the technical field of agricultural fertilization. Crop canopy growth information is obtained based on a sensor installed on a double-helix fertilization machine; and according to the obtained crop canopy growth information, fitting a drip line position of the crop, and extracting an accurate curve of the drip line of the crop. Through canopy information perception, the nutrient requirements of crops can be accurately recognized, a control strategy is provided for adjustment of the fertilization amount, fertilizer waste caused by blind fertilization is avoided, the fertilization amount is properly reduced in an area with vigorous growth, and nutrient excess is prevented; in a region with weak growth vigor, the fertilization amount is increased, the growth requirements of crops are met, the fertilization amount is reduced, soil and water pollution caused by excessive fertilization is reduced, the ecological environment is protected, meanwhile, the uniform distribution of the fertilizer can be ensured by monitoring and adjusting the fertilization speed in real time, and the utilization efficiency of the fertilizer is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural fertilization, and in particular to a lateral displacement fertilization control method based on canopy information perception. Background Art

[0002] In agronomy, the growth status of crops is closely related to their nutritional needs. Therefore, understanding the growth status of crops is a prerequisite for precise fertilization. The canopy is an important interface for crops to interact with the external environment. Its information can reflect the growth status, nutritional status, and health status of crops. Automatic control technology is the key to precise fertilization. The crop canopy information is obtained in real time through sensors. After analysis and processing, the automatic control technology is used to adjust the fertilizer application amount and fertilizer application position of the fertilizer applicator to achieve precise fertilization.

[0003] Fertilization operation requires that fertilizer be applied near the root system of crops, at which time the crops absorb fertilizer best. Most existing fertilizer applicators apply fertilizer by opening straight furrows between rows, which affects fertilizer absorption. Studies have shown that the root system at the vertical projection of the drip line along the crop canopy is the place where fertilizer absorption is most active. Therefore, how to obtain crop growth data in different areas through the perception of crop canopy information, analyze the growth status of crops, and then determine the area and amount of fertilization is the problem we need to solve. To this end, a lateral displacement fertilization control method based on canopy information perception is proposed. Summary of the invention

[0004] The object of the present invention is to provide a lateral displacement fertilization control method based on canopy information perception to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A lateral displacement fertilization control method based on canopy information perception comprises the following steps: Step 1, obtaining crop canopy growth information based on sensors installed on a double-screw fertilizer spreader; Step 2: Fit the drip line position of the crop based on the acquired crop canopy growth information, and extract the precise drip line curve of the crop. The drip line is the trace left after the water evaporates from the edge of the crop canopy, and is usually also the area where the root distribution is more concentrated. Step 3, according to the distance from the trunk to the drip line and the canopy structure of the crop, a theoretical curve of the lateral fertilization position is established using geometric principles to provide a theoretical basis for the precise fertilization of the fertilizer applicator. For fruit trees, the trunk is taken as the center of the circle and the lateral distance from the trunk to the drip line of the canopy is taken as the radius, so as to calculate the most suitable position for fertilization. The theoretical curve of the lateral fertilization position represents the position where the fertilizer should be applied to ensure that the fertilizer can be as close to the root system of the crop as possible and improve the absorption efficiency of the fertilizer; Step 4: According to the established theoretical curve of lateral fertilization position, the fertilization area is determined and the operation path of the double-screw fertilizer spreader is planned. When there is a gap between two fruit trees or crops, the double-screw fertilizer spreader moves in a straight line at the gap without fertilizing. Fertilization operation will continue only when the theoretical fertilization position of the next fruit tree or crop is reached, so as to avoid fertilizing in invalid areas. Step 5: monitor the actual position of the double-spiral fertilizer applicator during the fertilization operation in real time, compare the actual position with the theoretical curve position, adjust the lateral swing distance and swing speed of the fertilizer applicator according to the deviation value, control the left and right swing of the double-spiral fertilizer applicator, and ensure that the fertilizer applicator operates along the theoretical curve; Step 6: Dynamically adjust the amount and speed of fertilizer application according to the growth status and fertilizer requirements of the crops to ensure efficient use of fertilizers. Through real-time monitoring of the crop canopy, analyze the nutritional needs and growth status of the crops. During the fertilization process, adjust the amount of fertilizer in real time, reduce the amount of fertilizer in areas with vigorous crop growth, and increase the amount of fertilizer in areas with weaker growth.

[0006] A further improvement of the technical solution of the present invention is that in step 1, the process of acquiring crop canopy growth information is as follows: Step 11, deploying hyperspectral sensors and machine vision sensors on the double-auger fertilizer spreader to ensure that the sensors can cover most areas of the crop canopy in order to obtain comprehensive canopy information, and calibrating the sensors. Then, according to the crop type and growth cycle, configure the parameters of the sensor sampling frequency and data transmission format to adapt to different operating environments and crop types; Step 12, when the double-auger fertilizer spreader passes through the crop, the sensor collects image information and spectral information of the crop canopy in real time, obtains crop canopy growth information including canopy height, canopy width, normalized vegetation index and chlorophyll content, and transmits the collected data to the control system of the double-auger fertilizer spreader in real time; Step 13, preprocessing the crop canopy growth information, including denoising and enhancement processing steps, wherein the collected images are denoised and enhanced to improve image quality, reduce the impact of environmental factors on the images, and integrate the preprocessed crop canopy growth information into a unified data set.

[0007] A further improvement of the technical solution of the present invention is that in step 2, the extraction process of the crop drip line accurate curve is: Step 21, using image processing software to convert the collected color image into a grayscale image, performing binarization processing on the grayscale image, and dividing the pixels in the image into two categories: foreground and background, wherein the foreground is set to white and the background is set to black; Step 22, using the Canny edge detection algorithm to process the binarized image, using the edge pixels output by the Canny edge detection result to identify the edge of the crop canopy and form the outline of the crop canopy, wherein the Canny algorithm can detect strong edges and weak edges in the image and improve the accuracy of edge detection by suppressing false edges; Step 23, using a polynomial fitting curve fitting method to fit the detected canopy edge to obtain a smooth curve of the canopy contour, and preliminarily estimate the position of the drip line according to the shape and position of the canopy contour curve, wherein the drip line is usually located on the inner side of the canopy edge and is the trace left after water evaporation. Its position can be estimated by the inward offset of the canopy contour; Step 24, using the curve fitting method of Bezier curve fitting to fit the initially estimated drip line position, using the Bezier curve fitting result to output a smooth and continuous curve to obtain the precise curve of the crop drip line.

[0008] A further improvement of the technical solution of the present invention is that the expression of the crop drip line accurate curve is: ; ; In the formula, It is the precise curve of the crop drip line, representing the points on the Bezier curve. is the kth control point, which is a two-dimensional coordinate. m is the order of the Bezier curve, which is the number of control points minus one. is a parameter with a value range of [0,1]. is the number of combinations, which means the number of combinations of k elements from m different elements. and Respectively and The power of =0, the starting point of the curve is at ,when =1, the end point of the curve is at ,along with From 0 to 1, the curve starts from the starting point Smooth transition to the end point , the middle control point , , , Determines the shape and curvature of the curve.

[0009] A further improvement of the technical solution of the present invention is that in step 3, the process of establishing the theoretical curve of the horizontal fertilization position is as follows: Step 31, obtain the precise position of the drip line through image processing and curve fitting method (Bezier curve fitting), and use the positioning sensor to determine the position of the trunk, and record the coordinates of the trunk as ; Step 32, for each point on the drip line , calculate its coordinates with the trunk The Euclidean distance , to obtain the distance from the trunk to the drip line, and calculate the average distance from all drip line points to the trunk ; Step 33, with the trunk as the center and the average distance from all drip line points to the trunk as the radius, draw a circle as a preliminary horizontal fertilization position theoretical curve. The horizontal fertilization position theoretical curve is a circle with the trunk as the center, indicating the position where the fertilizer should be applied, and then generate points on the theoretical curve according to the parametric equation of the circle. ; Step 34, fine-tune the fertilization position according to the crop canopy structure, and calculate and adjust the fertilization radius according to the canopy structure and soil conditions If the canopy is denser in some directions, the fertilization radius can be appropriately increased; if the canopy is denser on the north side, the fertilization radius on the north side can be appropriately increased; Step 35, adjust the fertilization radius according to and the coordinates of the tree trunk to regenerate the final theoretical curve of lateral fertilization position.

[0010] A further improvement of the technical solution of the present invention is that in step 4, the process of planning the operation path of the double-screw fertilizer spreader is: Step 41, read the final horizontal fertilization position theoretical curve data, and define the fertilization area, wherein the fertilization area is a circle with the tree trunk as the center and The circular area with a radius of , and calculate the inner and outer boundaries of the fertilization area. The inner boundary radius can be slightly smaller than , the outer boundary radius can be slightly larger than ; Step 42, initialize the operation path of the double spiral fertilizer spreader, select a starting point on the inner boundary or outer boundary of the fertilization area as the path starting point of the double spiral fertilizer spreader, plan an operation path of the double spiral fertilizer spreader according to the boundary of the fertilization area, and obtain the coordinate points on it as , wherein the double spiral operation path moves in a spiral motion along the boundary of the fertilization area to ensure that the entire fertilization area is covered; Step 43, when there is a gap between two fruit trees or crops, the gap area is detected, and the fertilizer spreader is set to turn off the fertilization function in the straight driving section and automatically turn it on when it reaches the fertilization area, wherein the gap area refers to the blank area between the two fertilization areas, and the width of the gap area is determined according to the arrangement density of the fruit trees or crops and the operation width of the fertilizer spreader. The path planning ensures that the fertilizer spreader passes quickly in the gap area without performing fertilization operations; Step 44, connect the operating path of the double-spiral fertilizer applicator in the fertilization area and the straight path in the spacing area to generate a final operating path. During the fertilization operation, start the double-spiral fertilizer applicator to drive in a straight line between the crop rows. During the driving process, monitor the position of the double-spiral fertilizer applicator in real time to ensure that it moves along the planned fertilization path, and control the opening and closing of the fertilization function according to the position information.

[0011] A further improvement of the technical solution of the present invention is that the expression of the operation path of the double-spiral fertilizer spreader is: ; ; In the formula, is the coordinate point of the double helix operation path, are the coordinates of the tree trunk, is the adjusted fertilization radius, is the inner border radius adjustment value, is the outer border radius adjustment value, is a parameter whose value range is [0, T]. T is the total length of the spiral path, which is determined by the size of the fertilization area and the density of the spiral path. From 0 to T, the radius increases from - Gradually increase to + , and Follow the circular path with a spiral motion to ensure that the entire fertilization area is covered.

[0012] A further improvement of the technical solution of the present invention is that in step 5, the process of controlling the left and right swing of the double-helix fertilizer spreader is: Step 51: monitor the position information of the double-spiral fertilizer applicator in real time according to the GPS installed on the double-spiral fertilizer applicator to obtain the actual position coordinates of the double-spiral fertilizer applicator. ; Step 52: Load the theoretical curve data of the horizontal fertilization position and obtain the theoretical position coordinates. , compare the actual position of the fertilizer applicator monitored in real time with the corresponding position on the theoretical curve, calculate the deviation between the actual position and the theoretical position of the fertilizer applicator, and convert the deviation into lateral swing distance and swing speed in combination with the forward speed information of the machine; Step 53, judging whether the current deviation is within an acceptable range according to a preset deviation threshold, if the deviation exceeds the preset deviation threshold, adjustment is required, if the deviation is within the preset deviation threshold, monitoring is continued; Step 54, design a PID control algorithm, adjust the lateral swing distance and swing speed of the fertilizer spreader according to the deviation value, and adjust the parameters of the PID controller according to the actual operation conditions. , and ; Step 55, according to the control signal calculated by the PID control algorithm, a control instruction is sent to the control system of the double spiral fertilizer applicator to adjust the lateral swing distance of the double spiral fertilizer applicator, and the swing speed of the fertilizer applicator is adjusted according to the lateral swing distance, and the lateral swing distance and the swing speed of the fertilizer applicator are adjusted in real time in combination with the calculated lateral swing distance adjustment value and the swing speed adjustment value to ensure that the fertilizer applicator operates along the theoretical curve; Step 56, monitor the actual position of the fertilizer spreader in real time, compare the actual position with the theoretical position, and continue to adjust the lateral swing distance and swing speed of the fertilizer spreader according to the deviation value to form a closed-loop control.

[0013] A further improvement of the technical solution of the present invention is that the deviation expression between the actual position and the theoretical position of the fertilizer applicator is: ; ; In the formula, is the deviation between the actual position and theoretical position of the fertilizer applicator, is the actual position coordinate, is the theoretical position coordinate; The expressions of the lateral swing distance and the swing speed are: ; ; In the formula, is the lateral deflection distance, is the yaw speed, is the sampling time interval; The expression of the PID control algorithm is: ; In the formula, is the control signal, is the deviation, , and are proportional, integral and differential gains respectively, and t is time, which is a continuous time variable used to represent the deviation at different time points in the control process. and control signals ; The expressions of the lateral yaw distance adjustment value and the yaw speed adjustment value are: ; ; In the formula, is the lateral swing distance adjustment value, is the control signal calculated according to the PID control algorithm, is the yaw speed adjustment value, is the maximum allowable swing distance.

[0014] A further improvement of the technical solution of the present invention is that in step 6, the process of dynamically adjusting the amount of fertilizer and the speed of fertilizer application is: Step 61, calculating a crop state evaluation index based on the collected crop canopy growth information including canopy height, canopy width, normalized difference vegetation index and chlorophyll content, and evaluating the nutritional requirements and growth status of the crop; Step 62, based on the evaluation results of the crop's nutritional needs and growth status, analyze the fertilizer needs of different areas, identify areas with vigorous growth and areas with weaker growth, and then calculate the fertilizer amount for each area according to a preset fertilization plan to ensure that fertilizer can be distributed as needed; Step 63, sending a control instruction to the control system of the double-screw fertilizer applicator according to the calculated fertilizer application amount and fertilizer application speed, adjusting the fertilizer application amount of the double-screw fertilizer applicator to ensure accurate fertilizer application; Step 64, real-time monitoring of the actual position of the double-screw fertilizer applicator, as well as the nutrient requirements and growth status of the crop, comparing the actual position with the theoretical position, and continuing to adjust the fertilizer application amount and speed of the fertilizer applicator according to the deviation value. Through continuous monitoring and adjustment, it is ensured that the fertilizer applicator always operates according to the preset fertilization plan, thereby improving the accuracy and efficiency of fertilization; Wherein, the expression of the crop status evaluation index is: ; In the formula, S is the crop status evaluation index, which represents the comprehensive evaluation value of the crop's nutritional needs and growth status, N is the number of crop canopy growth indicators, are the values ​​of the jth crop canopy growth index, representing canopy height, canopy width, normalized vegetation index and chlorophyll content, respectively. is the weight of the j-th crop canopy growth index. The value range of S is between 0 and 1. When the values ​​of all crop canopy growth indicators are 0, S=0. When the values ​​of all crop canopy growth indicators are the maximum, S is close to 1.

[0015] Due to the adoption of the above technical solution, the present invention has the following technical advances compared with the prior art: The present invention provides a lateral displacement fertilization control method based on canopy information perception. Through canopy information perception, the nutritional needs of crops can be accurately identified to avoid fertilizer waste caused by blind fertilization. In areas with vigorous growth, the amount of fertilizer is appropriately reduced to prevent nutrient excess. In areas with weaker growth, the amount of fertilizer is increased to meet the nutritional needs of crops. This not only improves the utilization rate of fertilizers, but also reduces soil and water pollution caused by excessive fertilization, which is beneficial to protecting the ecological environment. At the same time, through real-time monitoring and adjustment of the fertilization speed, the uniform distribution of fertilizers can be ensured, further improving the utilization efficiency of fertilizers.

[0016] The present invention provides a lateral displacement fertilization control method based on canopy information perception. By real-time collection of crop canopy growth information, including canopy height, canopy width, normalized vegetation index and chlorophyll content, the method can accurately reflect the nutritional needs and growth status of crops, thereby providing a basis for dynamically adjusting the amount and position of fertilizer application, ensuring that fertilizer can be accurately applied to crops, thereby improving fertilizer absorption efficiency, reducing fertilizer waste, reducing agricultural production costs, and reducing pollution to the environment, thereby achieving sustainable development of agriculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0018] Figure 1 is a flow chart of the method of the present invention; Figure 2 A flow chart of dynamically adjusting the amount and speed of fertilization according to the present invention; Figure 3 The figure is a schematic diagram of the appearance of the double-screw fertilizer spreader of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1, as Figure 1 , Figure 3As shown, the present invention provides a lateral displacement fertilization control method based on canopy information perception, comprising the following steps: Step 1: Obtain crop canopy growth information based on the sensors installed on the double-auger fertilizer spreader. Deploy hyperspectral sensors and machine vision sensors on the double-auger fertilizer spreader to ensure that the sensors can cover most areas of the crop canopy in order to obtain comprehensive canopy information. Calibrate the sensors to ensure their measurement precision and accuracy. Perform spectral calibration on the hyperspectral sensor to ensure that the spectral data measured is accurate. Perform image calibration on the machine vision sensor, including lens distortion correction, color correction, etc., to improve image quality. Then, configure the parameters of sensor sampling frequency and data transmission format according to crop type and growth cycle. The double-auger fertilizer spreader can adapt to different working environments and crop types. When the double-auger fertilizer spreader passes through the crop, the sensor collects the image information and spectral information of the crop canopy in real time, obtains the crop canopy growth information including canopy height, canopy width, normalized vegetation index and chlorophyll content, and transmits the collected data to the control system of the double-auger fertilizer spreader in real time, and pre-processes the crop canopy growth information, including the steps of denoising and enhancing, wherein the collected image is denoised and enhanced to improve the image quality, reduce the impact of environmental factors on the image, and integrate the pre-processed crop canopy growth information into a unified data set; Step 2: According to the acquired crop canopy growth information, the drip line position of the crop is fitted, and the precise curve of the crop drip line is extracted. The drip line is the trace left after the water evaporates at the edge of the crop canopy, and it is usually also the area where the root distribution is relatively concentrated. The collected color image is converted into a grayscale image using image processing software, and the grayscale image is binarized to divide the pixels in the image into foreground and background. The foreground is set to white and the background is set to black. The binarized image is processed using the Canny edge detection algorithm, and the edge pixels output by the Canny edge detection result are used to identify the edge of the crop canopy and form the contour of the crop canopy. The nny algorithm can detect strong and weak edges in an image and improve the accuracy of edge detection by suppressing false edges. The detected canopy edge is fitted using a curve fitting method of polynomial fitting to obtain a smooth curve of the canopy contour, and the position of the drip line is preliminarily estimated based on the shape and position of the canopy contour curve. The drip line is usually located on the inner side of the canopy edge and is the trace left after water evaporation. Its position can be estimated by the inward offset of the canopy contour. The Bezier curve fitting method is used to fit the preliminarily estimated drip line position, and the Bezier curve fitting result is used to output a smooth and continuous curve to obtain the precise drip line curve of the crop. Furthermore, the expression of the crop drip line exact curve is: ; ; In the formula, It is the precise curve of the crop drip line, representing the points on the Bezier curve. is the kth control point, which is a two-dimensional coordinate. m is the order of the Bezier curve, which is the number of control points minus one. is a parameter with a value range of [0,1]. is the number of combinations, which means the number of combinations of k elements from m different elements. and Respectively and The power of =0, the starting point of the curve is at ,when =1, the end point of the curve is at ,along with From 0 to 1, the curve starts from the starting point Smooth transition to the end point , the middle control point , , , Determines the shape and curvature of the curve; Step 3, according to the distance from the trunk to the drip line and the canopy structure of the crop, the theoretical curve of the lateral fertilization position is established using geometric principles to provide a theoretical basis for the precise fertilization of the fertilizer applicator. For fruit trees, the trunk is taken as the center of the circle and the lateral distance from the trunk to the drip line of the canopy is taken as the radius to deduce the most suitable position for fertilization. The theoretical curve of the lateral fertilization position represents the position where the fertilizer should be applied to ensure that the fertilizer can be as close to the root system of the crop as possible and improve the absorption efficiency of the fertilizer. The precise position of the drip line is obtained through image processing and curve fitting method (Bezier curve fitting), and the position of the trunk is determined using a positioning sensor. The coordinates of the trunk are recorded as , for each point on the drip line , calculate its coordinates with the trunk The Euclidean distance , to obtain the distance from the trunk to the drip line, and calculate the average distance from all drip line points to the trunk , where the distance from the tree trunk to the drip line is calculated as: , the average distance from all drip line points to the tree trunk is calculated as: , n is the number of points on the drip line; with the trunk as the center and the average distance from all drip line points to the trunk as the radius, a circle is drawn as the preliminary theoretical curve of horizontal fertilization position. The theoretical curve of horizontal fertilization position is a circle with the trunk as the center, indicating the position where fertilizer should be applied. Then, according to the parametric equation of the circle, the points on the theoretical curve are generated. ,in, , , is a parameter with a value range of [0, 2π]. It fine-tunes the fertilization position according to the crop canopy structure and calculates and adjusts the fertilization radius according to the canopy structure and soil conditions. If the canopy is denser in some directions, the fertilization radius can be appropriately increased. If the canopy is denser on the north side, the fertilization radius on the north side can be appropriately increased. The expression for adjusting the fertilization radius is: , is a distance adjusted according to canopy structure and soil conditions. It can be a small positive or negative number. If the canopy is denser on the north side, you can set A positive number, according to which the fertilization radius is adjusted and the coordinates of the trunk to regenerate the final theoretical curve of horizontal fertilization position. The point on the final theoretical curve of horizontal fertilization position is ;in, , ; Step 4: According to the established theoretical curve of lateral fertilization position, the fertilization area is determined and the operation path of the double-screw fertilizer spreader is planned. When there is a gap between two fruit trees or crops, the double-screw fertilizer spreader moves in a straight line at the gap without fertilizing. Fertilization operation will continue only when the theoretical fertilization position of the next fruit tree or crop is reached, so as to avoid fertilizing in invalid areas. Step 5: monitor the actual position of the double-spiral fertilizer applicator during the fertilization operation in real time, compare the actual position with the theoretical curve position, adjust the lateral swing distance and swing speed of the fertilizer applicator according to the deviation value, control the left and right swing of the double-spiral fertilizer applicator, and ensure that the fertilizer applicator operates along the theoretical curve; Step 6: Dynamically adjust the amount and speed of fertilizer application according to the growth status and fertilizer requirements of the crops to ensure efficient use of fertilizers. Through real-time monitoring of the crop canopy, analyze the nutritional needs and growth status of the crops. During the fertilization process, adjust the amount of fertilizer in real time, reduce the amount of fertilizer in areas with vigorous crop growth, and increase the amount of fertilizer in areas with weaker growth.

[0021] Embodiment 2, as Figure 2 , Figure 3 As shown, based on Example 1, the present invention provides a technical solution: Preferably, in step 4, the process of planning the operation path of the double-screw fertilizer spreader is: Read the final theoretical curve data of horizontal fertilization position and define the fertilization area, where the fertilization area is a circle with the tree trunk as the center and The circular area with a radius of , and calculate the inner and outer boundaries of the fertilization area. The inner boundary radius can be slightly smaller than , the outer boundary radius can be slightly larger than , initialize the operation path of the double spiral fertilizer spreader, select a starting point on the inner or outer boundary of the fertilization area as the path starting point of the double spiral fertilizer spreader, and plan an operation path of the double spiral fertilizer spreader according to the boundary of the fertilization area, and obtain the coordinate points on it as , wherein the double-helix operation path performs spiral motion along the boundary of the fertilization area to ensure that the entire fertilization area is covered. When there is a gap between two fruit trees or crops, the gap area is detected, and the fertilizer spreader is set to turn off the fertilization function in the straight driving section and automatically turn it on when it reaches the fertilization area. The gap area refers to the blank area between the two fertilization areas. The width of the gap area is determined according to the arrangement density of the fruit trees or crops and the operation width of the fertilizer spreader. The path planning ensures that the fertilizer spreader passes quickly in the gap area without fertilizing. The double-helix fertilizer spreader operation path in the fertilization area and the straight path of the gap area are connected to generate the final operation path. During the fertilization operation, the double-helix fertilizer spreader is started to travel in a straight line between the crop rows. During the driving process, the position of the double-helix fertilizer spreader is monitored in real time to ensure that it travels along the planned fertilization path, and the opening and closing of the fertilization function is controlled according to the position information; Furthermore, the expression of the operation path of the double-screw fertilizer spreader is: ; ; In the formula, is the coordinate point of the double helix operation path, are the coordinates of the tree trunk, is the adjusted fertilization radius, is the inner border radius adjustment value, is the outer border radius adjustment value, is a parameter whose value range is [0, T]. T is the total length of the spiral path, which is determined by the size of the fertilization area and the density of the spiral path. From 0 to T, the radius increases from - Gradually increase to + , and Perform spiral movements along a circular path to ensure that the entire fertilization area is covered; In step 5, the process of controlling the left and right swing of the double spiral fertilizer spreader is: According to the GPS installed on the double spiral fertilizer applicator, the position information of the double spiral fertilizer applicator is monitored in real time to obtain the actual position coordinates of the double spiral fertilizer applicator. , load the theoretical curve data of the horizontal fertilization position and obtain the theoretical position coordinates , compare the actual position of the fertilizer spreader monitored in real time with the corresponding position on the theoretical curve, calculate the deviation between the actual position and the theoretical position of the fertilizer spreader, and convert the deviation into lateral swing distance and swing speed in combination with the forward speed information of the machine. According to the preset deviation threshold, judge whether the current deviation is within the acceptable range. If the deviation exceeds the preset deviation threshold, it needs to be adjusted. If the deviation is within the preset deviation threshold, continue to monitor and design a PID control algorithm. According to the deviation value, adjust the lateral swing distance and swing speed of the fertilizer spreader, and adjust the parameters of the PID controller according to the actual operation conditions. , and To ensure the control effect, if the swing distance is large, the speed can be appropriately reduced to adjust the position more accurately. If the swing distance is small, the speed can be maintained or appropriately increased to improve the working efficiency. According to the control signal calculated by the PID control algorithm, a control instruction is sent to the control system of the double-spiral fertilizer applicator to adjust the lateral swing distance of the double-spiral fertilizer applicator, and the swing speed of the fertilizer applicator is adjusted according to the lateral swing distance. Combined with the calculated lateral swing distance adjustment value and the swing speed adjustment value, the lateral swing distance and the swing speed of the fertilizer applicator are adjusted in real time to ensure that the fertilizer applicator operates along the theoretical curve. The actual position of the fertilizer applicator is monitored in real time, the actual position is compared with the theoretical position, and the lateral swing distance and the swing speed of the fertilizer applicator are continuously adjusted according to the deviation value to form a closed-loop control. Furthermore, the deviation expression between the actual position and the theoretical position of the fertilizer applicator is: ; ; In the formula, is the deviation between the actual position and theoretical position of the fertilizer applicator, is the actual position coordinate, is the theoretical position coordinate; The expressions of lateral swing distance and swing speed are: ; ; In the formula, is the lateral deflection distance, is the yaw speed, is the sampling time interval; The expression of PID control algorithm is: ; In the formula, is the control signal, is the deviation, , and are proportional, integral and differential gains respectively, and t is time, which is a continuous time variable used to represent the deviation at different time points in the control process. and control signals ; The expressions for the lateral yaw distance adjustment value and the yaw speed adjustment value are: ; ; In the formula, is the lateral swing distance adjustment value, is the control signal calculated according to the PID control algorithm, is the yaw speed adjustment value, is the maximum allowable swing distance; In step 6, the process of dynamically adjusting the amount and speed of fertilizer application is as follows: Step 61, calculating a crop state evaluation index based on the collected crop canopy growth information including canopy height, canopy width, normalized difference vegetation index and chlorophyll content, and evaluating the nutritional requirements and growth status of the crop; Step 62, based on the evaluation results of the crop's nutritional needs and growth status, analyze the fertilizer needs of different areas, identify areas with vigorous growth and areas with weaker growth, and then calculate the fertilizer amount for each area according to a preset fertilization plan to ensure that fertilizer can be distributed as needed; Step 63, sending a control instruction to the control system of the double-screw fertilizer applicator according to the calculated fertilizer application amount and fertilizer application speed, adjusting the fertilizer application amount of the double-screw fertilizer applicator to ensure accurate fertilizer application; Step 64, real-time monitoring of the actual position of the double-screw fertilizer applicator, as well as the nutrient requirements and growth status of the crop, comparing the actual position with the theoretical position, and continuing to adjust the fertilizer application amount and speed of the fertilizer applicator according to the deviation value. Through continuous monitoring and adjustment, it is ensured that the fertilizer applicator always operates according to the preset fertilization plan, thereby improving the accuracy and efficiency of fertilization; Among them, the expression of crop status evaluation index is: ; In the formula, S is the crop status evaluation index, which represents the comprehensive evaluation value of the crop's nutritional needs and growth status, N is the number of crop canopy growth indicators, are the values ​​of the jth crop canopy growth index, representing canopy height, canopy width, normalized vegetation index and chlorophyll content, respectively. is the weight of the j-th crop canopy growth index. The value range of S is between 0 and 1. When the values ​​of all crop canopy growth indexes are 0, S=0. When the values ​​of all crop canopy growth indexes are at the maximum value, S is close to 1. As the crop canopy growth index increases, the comprehensive evaluation value S also increases, but the rate of increase gradually slows down. If the value of S is low, it means that the nutritional demand and growth status of the crop are poor, and the amount of fertilizer needs to be increased. If the value of S is high, it means that the nutritional demand and growth status of the crop are good, and the amount of fertilizer can be appropriately reduced.

[0022] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A lateral displacement fertilization control method based on canopy information perception, characterized in that: The following steps are involved: Step 1, obtaining crop canopy growth information based on sensors installed on a double-screw fertilizer spreader; Step 2: fitting the drip line position of the crop based on the acquired crop canopy growth information, and extracting the precise drip line curve of the crop; Step 3, based on the distance from the tree trunk to the drip line and the canopy structure of the crop, a theoretical curve of lateral fertilization position is established using geometric principles; Step 4, judging the fertilization area according to the established lateral fertilization position theoretical curve, and planning the operation path of the double-screw fertilizer spreader; Step 5, real-time monitoring of the actual position of the double-screw fertilizer applicator during the fertilization operation, comparing the actual position with the theoretical curve position, adjusting the lateral swing distance and swing speed of the fertilizer applicator according to the deviation value, and controlling the left and right swing of the double-screw fertilizer applicator; Step 6: Dynamically adjust the amount and speed of fertilizer application according to the growth status and fertilizer requirements of the crops.

2. The lateral displacement fertilization control method based on canopy information perception according to claim 1 is characterized in that: In step 1, the process of acquiring crop canopy growth information is as follows: Step 11, deploying a hyperspectral sensor and a machine vision sensor on the double-screw fertilizer spreader, and calibrating the sensor, and then configuring the parameters of the sensor sampling frequency and data transmission format according to the crop type and growth cycle to adapt to different operating environments and crop types; Step 12, when the double-auger fertilizer spreader passes through the crop, the sensor collects image information and spectral information of the crop canopy in real time, obtains crop canopy growth information including canopy height, canopy width, normalized vegetation index and chlorophyll content, and transmits the collected data to the control system of the double-auger fertilizer spreader in real time; Step 13, preprocessing the crop canopy growth information, including denoising and enhancement processing steps, and integrating the preprocessed crop canopy growth information into a unified data set.

3. The lateral displacement fertilization control method based on canopy information perception according to claim 2 is characterized in that: In step 2, the extraction process of the crop drip line accurate curve is: Step 21, using image processing software to convert the collected color image into a grayscale image, performing binarization processing on the grayscale image, and dividing the pixels in the image into two categories: foreground and background, wherein the foreground is set to white and the background is set to black; Step 22, using the Canny edge detection algorithm to process the binarized image, using the edge pixels output by the Canny edge detection result to identify the edge of the crop canopy and form the outline of the crop canopy; Step 23, fitting the detected canopy edge using a polynomial fitting curve fitting method to obtain a smooth curve of the canopy contour, and preliminarily estimating the position of the drip line according to the shape and position of the canopy contour curve; Step 24, using the curve fitting method of Bezier curve fitting to fit the initially estimated drip line position, using the Bezier curve fitting result to output a smooth and continuous curve to obtain the precise curve of the crop drip line.

4. The lateral displacement fertilization control method based on canopy information perception according to claim 3 is characterized by: The expression of the crop drip line accurate curve is: ； ； In the formula, It is the precise curve of the crop drip line, representing the points on the Bezier curve. is the kth control point, which is a two-dimensional coordinate. m is the order of the Bezier curve, which is the number of control points minus one. is a parameter with a value range of [0,1]. is the number of combinations, which means the number of combinations of k elements from m different elements. and Respectively and The power of =0, the starting point of the curve is at ,when =1, the end point of the curve is at ,along with From 0 to 1, the curve starts from the starting point Smooth transition to the end point .

5. The lateral displacement fertilization control method based on canopy information perception according to claim 4 is characterized in that: In step 3, the process of establishing the theoretical curve of the horizontal fertilization position is as follows: Step 31, obtain the precise position of the drip line through image processing and curve fitting methods, and use the positioning sensor to determine the position of the trunk, and record the coordinates of the trunk as ; Step 32, for each point on the drip line , calculate its coordinates with the trunk The Euclidean distance , to obtain the distance from the trunk to the drip line, and calculate the average distance from all drip line points to the trunk , where the distance from the tree trunk to the drip line is calculated as: , the average distance from all drip line points to the tree trunk is calculated as: , n is the number of points on the drip line; Step 33, with the trunk as the center and the average distance from all drip line points to the trunk as the radius, draw a circle as a preliminary theoretical curve for horizontal fertilization position, and then generate points on the theoretical curve according to the parametric equation of the circle. ; Step 34, fine-tune the fertilization position according to the crop canopy structure, and calculate and adjust the fertilization radius according to the canopy structure and soil conditions ; Step 35, adjust the fertilization radius according to and the coordinates of the tree trunk to regenerate the final theoretical curve of lateral fertilization position.

6. The method for controlling lateral displacement fertilization based on canopy information perception according to claim 5, characterized in that: In step 4, the process of planning the operation path of the double-screw fertilizer spreader is as follows: Step 41, read the final horizontal fertilization position theoretical curve data, and define the fertilization area, wherein the fertilization area is a circle with the tree trunk as the center and is the circular area with radius, and calculate the inner and outer boundaries of the fertilization area; Step 42, initialize the operation path of the double spiral fertilizer spreader, select a starting point on the inner boundary or outer boundary of the fertilization area as the path starting point of the double spiral fertilizer spreader, plan an operation path of the double spiral fertilizer spreader according to the boundary of the fertilization area, and obtain the coordinate points on it as ; Step 43, when there is a gap between two fruit trees or crops, the gap area is detected, and the fertilizer spreader is set to turn off the fertilization function in the straight driving section and automatically turn it on when reaching the fertilization area, wherein the gap area refers to the blank area between the two fertilization areas, and the width of the gap area is determined according to the arrangement density of the fruit trees or crops; Step 44, connect the operating path of the double-spiral fertilizer applicator in the fertilization area and the straight path in the spacing area to generate a final operating path. During the fertilization operation, start the double-spiral fertilizer applicator to drive in a straight line between the crop rows. During the driving process, monitor the position of the double-spiral fertilizer applicator in real time to ensure that it moves along the planned fertilization path, and control the opening and closing of the fertilization function according to the position information.

7. The lateral displacement fertilization control method based on canopy information perception according to claim 6 is characterized by: The expression of the operation path of the double-screw fertilizer spreader is: ； ； In the formula, is the coordinate point of the double helix operation path, are the coordinates of the tree trunk, is the adjusted fertilization radius, is the inner border radius adjustment value, is the outer border radius adjustment value, is a parameter whose value range is [0,T], T is the total length of the spiral path, as From 0 to T, the radius increases from - Gradually increase to + .

8. The method for controlling lateral displacement fertilization based on canopy information perception according to claim 7, characterized in that: In step 5, the process of controlling the left and right swing of the double-screw fertilizer spreader is as follows: Step 51: monitor the position information of the double-spiral fertilizer applicator in real time according to the GPS installed on the double-spiral fertilizer applicator to obtain the actual position coordinates of the double-spiral fertilizer applicator. ; Step 52: Load the theoretical curve data of the horizontal fertilization position and obtain the theoretical position coordinates. , compare the actual position of the fertilizer applicator monitored in real time with the corresponding position on the theoretical curve, calculate the deviation between the actual position and the theoretical position of the fertilizer applicator, and convert the deviation into lateral swing distance and swing speed in combination with the forward speed information of the machine; Step 53, judging whether the current deviation is within an acceptable range according to a preset deviation threshold, if the deviation exceeds the preset deviation threshold, adjustment is required, if the deviation is within the preset deviation threshold, monitoring is continued; Step 54, design a PID control algorithm, adjust the lateral swing distance and swing speed of the fertilizer spreader according to the deviation value, and adjust the parameters of the PID controller according to the actual operation conditions. , and ; Step 55, according to the control signal calculated by the PID control algorithm, a control instruction is sent to the control system of the double spiral fertilizer applicator to adjust the lateral swing distance of the double spiral fertilizer applicator, and the swing speed of the fertilizer applicator is adjusted according to the lateral swing distance, and the lateral swing distance and the swing speed of the fertilizer applicator are adjusted in real time in combination with the calculated lateral swing distance adjustment value and the swing speed adjustment value; Step 56, monitor the actual position of the fertilizer spreader in real time, compare the actual position with the theoretical position, and continue to adjust the lateral swing distance and swing speed of the fertilizer spreader according to the deviation value to form a closed-loop control.

9. The method for controlling lateral displacement fertilization based on canopy information perception according to claim 8, characterized in that: The deviation expression between the actual position and the theoretical position of the fertilizer applicator is: ； ； In the formula, is the deviation between the actual position and theoretical position of the fertilizer applicator, is the actual position coordinate, is the theoretical position coordinate; The expressions of the lateral swing distance and the swing speed are: ； ； In the formula, is the lateral deflection distance, is the yaw speed, is the sampling time interval; The expressions of the lateral yaw distance adjustment value and the yaw speed adjustment value are: ； ； In the formula, is the lateral swing distance adjustment value, is the control signal calculated according to the PID control algorithm, is the yaw speed adjustment value, is the maximum allowable swing distance.

10. The method for controlling lateral displacement fertilization based on canopy information perception according to claim 9, characterized in that: In step 6, the process of dynamically adjusting the amount and speed of fertilization is as follows: Step 61, calculating a crop state evaluation index based on the collected crop canopy growth information including canopy height, canopy width, normalized difference vegetation index and chlorophyll content, and evaluating the nutritional requirements and growth status of the crop; Step 62, based on the evaluation results of the crop's nutritional needs and growth status, analyzing the fertilizer needs of different areas, identifying areas with vigorous growth and areas with weaker growth, and then calculating the fertilizer amount for each area according to a preset fertilization plan; Step 63, sending a control instruction to the control system of the double-screw fertilizer applicator according to the calculated fertilizer application amount and fertilizer application speed, and adjusting the fertilizer application amount of the double-screw fertilizer applicator; Step 64, real-time monitoring of the actual position of the double-screw fertilizer applicator, as well as the nutrient requirements and growth status of the crop, comparing the actual position with the theoretical position, and continuing to adjust the fertilizer application amount and speed of the fertilizer applicator according to the deviation value; Wherein, the expression of the crop status evaluation index is: ； In the formula, S is the crop status evaluation index, N is the number of crop canopy growth indicators, are the values ​​of the jth crop canopy growth index, representing canopy height, canopy width, normalized vegetation index and chlorophyll content, respectively. is the weight of the j-th crop canopy growth index. The value range of S is between 0 and 1. When the values ​​of all crop canopy growth indicators are 0, S=0. When the values ​​of all crop canopy growth indicators are the maximum, S is close to 1.

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