An adaptive wind volume and direction control method and system based on fruit tree canopy characteristics

Abstract

This invention discloses an adaptive airflow and direction control method and system based on fruit tree canopy characteristics, belonging to the field of agricultural plant protection machinery. The system includes a three-dimensional lidar mounted on the front end of a mobile chassis, a contouring module mounted on the rear end of the chassis, and a controller, air delivery module, and spraying module located on the chassis. During operation, the system first performs initialization self-checks and resets; then, the controller extracts the maximum two-dimensional contour of the canopy based on the lidar point cloud and completes area division based on the air outlet layout; next, it generates contouring motion commands for the robotic arm based on the contour segmentation fitting results; finally, it calculates the total airflow according to operational requirements and determines the distribution ratio of each air outlet and the fan speed, with real-time monitoring and closed-loop feedback throughout the process. This invention effectively improves droplet drift and pesticide loss caused by inaccurate wind direction and improper airflow, enhancing the uniformity and utilization rate of pesticide deposition within the canopy while reducing environmental pollution during application.

Description

Technical Field

[0001] This invention belongs to the field of agricultural plant protection machinery, specifically relating to an adaptive wind volume and direction control method and system based on the characteristics of fruit tree canopy. Background Technology

[0002] Pest and disease control is a crucial aspect of ensuring fruit yield and quality, currently relying primarily on pesticide spraying. Air-assisted spraying technology uses airflow to rotate leaves, ensuring even coverage of the leaf surface and underside with pesticide. This significantly enhances the penetration and deposition stability of droplets within the canopy, effectively improving pesticide utilization efficiency and overall pest and disease control. Therefore, it is widely used in orchard spraying operations.

[0003] Currently, commonly used wind-assisted sprayers rely on radial high-speed airflow generated by a fan to deliver droplets, but this method is prone to severe droplet drift. To overcome this deficiency, existing research has continuously improved wind-assisted spraying technology from different perspectives, mainly in the following aspects: First, by changing the type of fan or the shape of the air outlet to improve airflow distribution, for example, by using tower fans or multi-outlet designs to disperse the concentrated airflow into multiple layers to match the penetration needs of different parts of the fruit tree canopy; Second, by using mechanical structures to enable the spraying device to follow the tree shape, for example, by setting main and secondary air outlets to meet the spraying needs of different height areas of the canopy, or by using intelligent control methods to independently adjust the airflow according to height segments; Third, by using detection methods such as lidar to obtain target information of the fruit tree, for example, by using two-dimensional lidar to collect information on the canopy outline, volume, and density of the fruit tree, and adjusting the airflow and spray volume of the wind-assisted device accordingly.

[0004] While these technologies have improved the problem of droplet drift to some extent, they still have certain limitations. First, methods that improve airflow distribution by changing the type of fan or the shape of the air outlet, although alleviating the problems of top drift and insufficient penetration in the middle and lower parts caused by a single airflow to some extent, cannot be dynamically adjusted according to changes in the growth stage of the fruit trees, making it difficult to adapt to complex and ever-changing field conditions. Second, methods that use mechanical structures to make the spraying device follow the shape of the tree are mainly limited to single-dimensional airflow adjustment, lacking the ability to adjust the wind direction in real time according to the dynamic three-dimensional canopy contour, making it difficult to achieve precise contour-following spraying for complex canopy structures. Finally, methods that obtain fruit tree target information through detection means such as lidar mostly focus on detecting the presence or absence of targets or roughly classifying and controlling airflow, and have not yet established a refined collaborative control model between airflow, wind direction and three-dimensional canopy characteristics. This results in a mismatch between the airflow field and the canopy structure in actual operation, and the problems of droplet drift and insufficient penetration have not been fundamentally solved. In view of the shortcomings of the existing technology, the present invention proposes an adaptive wind volume and direction control system and method based on the characteristics of fruit tree canopy, aiming to solve the problem of coordinated adaptive control of wind volume and direction. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive airflow and direction control system and method based on the characteristics of fruit tree canopy, which can effectively solve the problems of mismatch between the airflow field of the sprayer and the canopy structure, droplet drift and insufficient penetration in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: an adaptive wind volume and direction control method based on the characteristics of fruit tree canopy, comprising the following steps: S1. System initialization and self-test: After the system starts, the controller resets each actuator to the preset safe position and performs self-calibration on all sensors. At the same time, the controller establishes communication with each module and performs stability verification. After confirming that the status of each component is normal, the controller controls the sprayer to travel to the starting position of the operation. S2. Three-dimensional information perception and feature extraction of the canopy: The canopy of the target fruit tree is scanned by a three-dimensional lidar and three-dimensional point cloud data of the canopy is collected; the collected canopy point cloud data is processed by the controller and a maximum two-dimensional canopy contour profile perpendicular to the forward direction of the sprayer is constructed, and the maximum two-dimensional canopy contour profile is used as the reference for the robotic arm to follow the shape; at the same time, according to the preset air outlet layout, the canopy space is dynamically divided into several independent three-dimensional operation sub-regions corresponding to the number of air outlets, and the volume of each sub-region is calculated and used as the basis for air volume calculation; S3. Contouring command generation: Based on the maximum two-dimensional canopy profile extracted in step S2 and the real-time pose of the sprayer, the contour curve corresponding to each robotic arm working segment is segmented and linearized. Based on this, the translation distance and target angle of each joint of each robotic arm working segment are calculated, and the contouring motion command that drives the robotic arm working segment to conform to the canopy contour is generated. S4. Adaptive air volume and wind speed calculation based on canopy characteristics: The system first calculates the theoretical total air volume required for spraying operations based on the canopy characteristic parameters of the fruit trees on both sides of the sprayer. Then, according to the volume ratio of the sub-regions corresponding to each air outlet, the theoretical total air volume is dynamically allocated to each air outlet in proportion. Finally, the corresponding target wind speed is calculated in combination with the area of ​​the air outlet. S5. Fan speed control: Based on the theoretical total air volume calculated in step S4 and the target wind speed distribution at each air outlet, the controller adjusts the fan speed to achieve a stable output of the theoretical total air volume and match the wind speed at each air outlet. S6. Closed-loop feedback adjustment: The actual rotation angle of the robotic arm is collected in real time by the angle sensors of each joint of the robotic arm, and the measured wind speed of each air outlet is obtained by the wind speed sensor. The measured values ​​are compared with the target angle and target wind speed set in steps S3 and S4 to calculate the angle error and air volume error. Based on the error value, the speed of the robotic arm joint actuator and the fan is corrected in real time by the control algorithm to dynamically maintain the stable operation and precise operation of the system, and realize the closed-loop adjustment of the operation process.

[0007] Further, the robotic arm in step S3 includes a central translation arm mounted on the mounting platform, an upper proximal rotating arm and a lower proximal rotating arm connected to both ends of the central translation arm, an upper distal rotating arm connected to the upper proximal rotating arm, and a lower distal rotating arm connected to the lower proximal rotating arm; the controller calculates the translation distance of the central translation arm and the rotation angles of the upper proximal rotating arm, the lower proximal rotating arm, the upper distal rotating arm, and the lower distal rotating arm.

[0008] Furthermore, the specific steps for generating the contouring command in step S3 are as follows: S31. Establish a two-dimensional local coordinate system with the midpoint of the central translation arm as the origin. The X-axis is the horizontal axis, which is perpendicular to the forward direction of the sprayer and points to the canopy on the working side. The Y-axis is vertically upward. Extract the contour point set from this two-dimensional profile and retain the single-sided point set facing the working side of the sprayer. S32. Based on the length ratio of the central translation arm, upper proximal rotating arm, lower proximal rotating arm, upper distal rotating arm, and lower distal rotating arm, the single-sided contour is divided into five continuous segments from top to bottom, and the mapping relationship between the contour point set of each segment and the corresponding robotic arm is established. S33. For the contour point set corresponding to each robotic arm segment, the least squares method is used to perform linear regression fitting to obtain the optimal fitting line for each segment, which serves as the benchmark for subsequent robotic arm posture adjustment. Among them, the central translation arm only performs horizontal movement, and its fitting line is calculated based solely on the X-axis coordinate of the corresponding contour point set. The fitting lines of the other rotating robotic arms need to be calculated by combining the X-axis and Y-axis coordinates. S34. By translating and rotating each robotic arm segment, the robotic arm axis is kept parallel to the corresponding fitted straight line, and the distance between them is equal to the preset working distance. This is to achieve posture matching between each robotic arm segment and the canopy contour.

[0009] Furthermore, the central translation arm described in step S34 is adjusted by horizontal linear movement, and its translation distance is... The expression is: In the formula, N is the number of points corresponding to the robotic arm. Preset the distance for the operation. Let x be the x-coordinate of the i-th contour point of the robotic arm; The remaining rotary robotic arms rotate around their respective hinge points to complete the attitude matching, and the expression for their rotation angle θ is: In the formula, Let be the ordinate of the i-th contour point of the robotic arm.

[0010] Furthermore, the expression for the total air volume in step S4 is: The expression for the air outlet wind speed is: In the formula, The total air volume required for the canopy. Canopy height, The number of air outlets. The diameter of the air outlet. The speed at which the sprayer travels. Let i be the distance from the i-th air outlet to the fruit tree canopy. The loss coefficient of air volume, The initial velocity to reach the canopy surface, Let be the air velocity at the i-th air outlet.

[0011] An adaptive airflow and direction control system based on fruit tree canopy characteristics includes: a mobile chassis, a three-dimensional lidar, a controller, a contouring module, an air delivery module, and a spraying module. The three-dimensional lidar is installed at the front end of the mobile chassis to acquire real-time characteristic information of the fruit tree canopy. The controller is fixed in an electrical control box above the mobile chassis and is electrically connected to the mobile chassis, the three-dimensional lidar, the contouring module, the air delivery module, and the spraying module. The contouring module is installed at the rear end of the mobile chassis and includes a mounting platform and symmetrically arranged robotic arms. The air delivery module includes a fan fixedly installed on the mobile chassis, a voltage stabilizing manifold connected to the fan, and an air delivery channel located on the air outlet side of the voltage stabilizing manifold. The spraying module includes a medicine tank, a medicine pump, and multiple nozzles connected sequentially through a medicine delivery pipeline. The medicine tank is fixed on the mobile chassis, and the nozzles are located at the airflow outlet of the air outlet, with the spray direction of the nozzles consistent with the airflow direction of the air outlet.

[0012] Furthermore, each set of robotic arms includes a central translation arm, an upper proximal rotating arm, a lower proximal rotating arm, an upper distal rotating arm, and a lower distal rotating arm. The central translation arm is vertically mounted on the mounting platform and can be raised and lowered relative to the platform. The front ends of the upper and lower proximal rotating arms are respectively hinged to the upper and lower ends of the central translation arm, and can be rotated toward the canopy around the hinge point by a motor drive. The upper distal rotating arm and the lower distal rotating arm are respectively hinged to the ends of their corresponding upper and lower proximal rotating arms, and can be further rotated toward the canopy around the hinge point by upper and lower electric actuators. The ends of the upper and lower distal rotating arms are both fixedly connected to the air delivery module.

[0013] Furthermore, the upper proximal rotating arm and the lower proximal rotating arm are of the same length, and the upper distal rotating arm and the lower distal rotating arm are of the same length.

[0014] Furthermore, the air delivery channel includes a splitter pipe and an air outlet. The air outlet is equipped with an adjustable flow guiding mechanism driven by a servo motor, and a wind speed sensor is installed at the outlet.

[0015] Furthermore, the voltage stabilizing collector is equipped with a flow equalization plate inside, which is used to evenly distribute the airflow to each air delivery channel.

[0016] The beneficial effects of the above technical solution are as follows: This invention achieves precise alignment between air outlets and the canopy using an adaptive contour matching method based on the characteristics of the fruit tree canopy. Specifically, this invention uses a 3D LiDAR to collect real-time point cloud data of the fruit tree canopy and extracts the largest two-dimensional canopy profile as the contour reference. A piecewise linearization method is used to divide the canopy profile into five independent segments according to the length ratio of the robotic arm, and least squares fitting is performed on each segment to generate the target pose of each robotic arm segment. Through the coordinated control of the motor and electric actuators, the central translation arm and four sets of rotating arms independently adjust their postures according to the actual shape of the canopy, achieving precise matching between the air outlet direction and the canopy profile. Compared to traditional integral or rocker-arm contouring mechanisms, this invention can closely fit the irregular surfaces of different tree shapes such as spindle-shaped and layered shapes, ensuring that each air outlet maintains a uniform working distance from each part of the canopy, and making the airflow spray range match the canopy profile in real time, reducing pesticide drift from the source.

[0017] This invention achieves precise, on-demand air delivery to different areas of the fruit tree canopy through an airflow distribution method based on the characteristics of the canopy. Specifically, according to a preset air outlet layout, the canopy space is dynamically divided into several independent three-dimensional operating sub-regions. Based on the canopy characteristic parameters of each sub-region, the theoretical total airflow is dynamically distributed proportionally to the corresponding air outlets. By coordinating the adjustment of the fan speed and the opening of the adjustable guide mechanism in each air outlet, precise, on-demand air delivery to different areas of the canopy is achieved, significantly improving the uniformity and utilization rate of pesticide deposition within the canopy and reducing environmental pollution during pesticide application.

[0018] This invention ensures stable and reliable operation through a fully closed-loop intelligent control system. Specifically, it integrates robotic arm joint angle sensors and outlet wind speed sensors to construct a complete closed-loop feedback control system. During operation, the controller collects the actual rotation angle of each joint of the robotic arm and the actual wind speed of each outlet in real time, and compares them with the preset target angle and target wind speed to calculate the angle error and air volume error. Simultaneously, based on the error value, the control algorithm dynamically corrects the robotic arm joint actuator and the fan speed or the opening of the adjustable guide mechanism, effectively overcoming disturbances such as robotic arm vibration caused by uneven field ground and wind speed fluctuations caused by changes in fan load. This ensures that the system maintains high-precision and stable operation in complex operating environments, achieving fully closed-loop intelligent control from perception to decision-making, execution, and finally feedback. Attached Figure Description

[0019] Figure 1 This is a flowchart of the control method of the present invention; Figure 2 This is a structural view of the control system of the present invention; Figure 3 This is an auxiliary view of the control system structure of the present invention; Figure 4This is a schematic diagram of the control system of the present invention.

[0020] Reference numerals: 1. Mobile chassis, 2. Battery pack, 3. 3D LiDAR, 4. Controller, 5. Mounting platform, 6. Left and right extension electric actuators, 7. Central translation arm, 8. Upper proximal rotating arm, 9. Lower proximal rotating arm, 10. Upper distal rotating arm, 11. Lower distal rotating arm, 12. Motor, 13. Upper and lower electric actuators, 14. Fan, 15. Voltage stabilizer and collector box, 16. Air delivery channel, 17. Flow equalization plate, 18. Flow divider, 19. Air outlet, 20. Servo motor, 21. Adjustable flow guiding mechanism, 22. Wind speed sensor, 23. Medicine tank, 24. Medicine pump, 25. Nozzle. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] It should be noted that, unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] It should also be noted that, unless otherwise stated, "multiple" or "several" refers to two or more, and the terms "upper" and "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Changes or adjustments to the relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0024] To address the problem of poor pesticide penetration and deposition, and pesticide waste, caused by existing orchard sprayers' inability to accurately adjust airflow parameters based on canopy differences, this invention discloses an adaptive airflow and direction control method and system based on orchard canopy characteristics. The control method process is as follows: Figure 1 As shown, the system architecture for implementing this method is as follows: Figure 2-3 As shown.

[0025] An adaptive airflow and direction control system based on fruit tree canopy characteristics includes: a mobile chassis 1, a three-dimensional lidar 3, a controller 4, a contouring module, an air delivery module, and a spray module.

[0026] The mobile chassis 1 preferably adopts a tracked structure to adapt to complex orchard ground, and is equipped with a battery pack 2 inside; the three-dimensional lidar 3 is installed at the front end of the mobile chassis 1 to acquire the three-dimensional contour and spatial distribution information of the fruit tree canopy in real time, and to provide environmental perception data for the system's contour control, air volume adjustment and precision spraying.

[0027] The controller 4 is fixed in the electrical control box above the mobile chassis 1. As the control core of the system, it can receive and process the data acquired by the three-dimensional lidar 3 in real time, and generate multi-modal collaborative control commands including contouring motion, air volume adjustment and spray start / stop. At the same time, the controller 4 is electrically connected to the mobile chassis 1, the three-dimensional lidar 3, the contouring module, the air delivery module and the spray module respectively, so as to realize the system's coordination and unified scheduling of each module.

[0028] The contouring module is installed at the rear end of the mobile chassis 1 and is used to realize the contouring movement of the fruit tree canopy. Its structure includes a mounting platform 5 and two sets of robotic arms arranged symmetrically on the left and right. The mounting platform 5 is installed on the mobile chassis 1 and is equipped with left and right extension electric push rods 6. The system can push the robotic arms to move horizontally as a whole through the left and right extension electric push rods 6 to adjust the working distance between the robotic arms and the fruit tree canopy. Each set of robotic arms includes a central translation arm 7, an upper proximal rotating arm 8, a lower proximal rotating arm 9, an upper distal rotating arm 10, and a lower distal rotating arm 11. The central translation arm 7 is vertically mounted on the mounting platform 5 and can be raised and lowered relative to the platform 5. The front ends of the upper proximal rotating arm 8 and the lower proximal rotating arm 9 are respectively hinged to the upper and lower ends of the central translation arm 7, and can be driven by the motor 12 to rotate around the hinge point toward the canopy. The upper distal rotating arm 10 and the lower distal rotating arm 11 are respectively hinged to the ends of their corresponding upper proximal rotating arms 8 and lower proximal rotating arms 9, and can be driven by the upper and lower electric push rods 13 to further rotate around the hinge point toward the canopy. The ends of the upper distal rotating arm 10 and the lower distal rotating arm 11 are fixedly connected to the air delivery module. Through the coordinated control of the motor 12 and the upper and lower electric push rods 13, the extension and angle adjustment of each arm segment can be realized, thereby completing the contouring of the canopy. In this embodiment, the motor 12 is a stepper motor.

[0029] Meanwhile, in order to facilitate the adjustment of the robotic arm for contouring, the upper proximal rotating arm 8 and the lower proximal rotating arm 9 are of the same length, and the upper distal rotating arm 10 and the lower distal rotating arm 11 are of the same length.

[0030] By coordinating the horizontal movement of the central translation arm 7 and the rotation of each rotating arm, the robotic arm can drive the air delivery and spray end effectors installed on it, so that the direction of the air outlet 19 can be adjusted according to the canopy contour, thereby achieving wind direction adjustment.

[0031] The air delivery module includes a fan 14 fixedly mounted on a mobile chassis 1, a voltage stabilizing manifold 15 connected to the air outlet of the fan 14, and air delivery channels 16 located on the air outlet side of the voltage stabilizing manifold 15. The fan 14 serves as the system's air source, and its rotation speed can be adjusted according to the total air volume requirement. The voltage stabilizing manifold 15 is equipped with a flow equalization plate 17 to stabilize and evenly distribute airflow, achieving low-loss delivery to each air delivery channel 16. The air delivery channels 16 are mounted on a robotic arm and can follow the arm's contour movement; their number can be set according to operational requirements. In this embodiment, the air delivery channels 16 include four independent air ducts.

[0032] Each air delivery channel 16 includes a diversion pipe 18 and an air outlet 19. The diversion pipe 18 is part of the air delivery channel 16, and its branch pipes can divert the airflow. The air outlet 19 is respectively located at the branch pipes of the diversion pipe 18 and the end of the air delivery channel 16, and is used to release the airflow in a directional manner.

[0033] Meanwhile, to achieve airflow control at each outlet, each outlet 19 is equipped with an adjustable flow guide mechanism 21 driven by a servo motor 20, and a wind speed sensor 22 is installed at the outlet. The adjustable flow guide mechanism 21 includes a connecting gear and a rotary valve. The servo motor 20 controls the opening of the rotary valve through the connecting gear to change the effective flow area of ​​the outlet, thereby controlling the size of the outlet and achieving dynamic adjustment of the outlet airflow. The wind speed sensor 22 can monitor the wind speed at the outlet 19 in real time and compare the measured value with the target wind speed. When the error exceeds a threshold, it is fed back to the system, allowing the system to compensate and adjust the fan speed 14 or the opening of the adjustable flow guide mechanism 21 to achieve closed-loop control.

[0034] Furthermore, by matching the diameter ratio of the diversion pipe 18 to the outlet duct, the initial airflow distribution at each outlet tends to be balanced. This homogenization design provides a stable basis for subsequent targeted dynamic adjustment of the airflow at the corresponding outlet 19 based on the volume and contour characteristics of different areas of the canopy.

[0035] The spray module includes a medicine tank 23, a medicine pump 24 for providing the pressure required for atomization, and multiple nozzles 25, which are connected in sequence through a medicine delivery pipeline. The medicine tank 23 is fixed on the mobile chassis 1, and the nozzles 25 are set at the airflow outlet of the air outlet 19. The spray direction of the nozzles 25 is consistent with the airflow direction of the air outlet 19. With the assistance of the auxiliary airflow, the medicine is atomized and directionally sprayed to the target canopy to achieve precise coverage of the target canopy.

[0036] Meanwhile, this application also provides an adaptive airflow and direction control method based on fruit tree canopy characteristics. This method can be applied to the aforementioned adaptive airflow and direction control system based on fruit tree canopy characteristics, and includes the following steps: S1. System initialization and self-test: After the system starts, the controller 4 resets each actuator to the preset safe position and performs self-calibration on all sensors. At the same time, the controller 4 establishes communication with each module and performs stability verification. After confirming that the status of each component is normal, it controls the sprayer to travel to the starting position of the operation.

[0037] S2. Three-dimensional information perception and feature extraction of the canopy: The three-dimensional lidar 3 scans the canopy of the target fruit tree and collects the three-dimensional point cloud data of the canopy; the controller 4 processes the collected canopy point cloud data and constructs the maximum two-dimensional canopy profile perpendicular to the forward direction of the sprayer, and uses the maximum two-dimensional canopy profile as the reference for the robotic arm to follow the shape; at the same time, according to the preset layout of the air outlets 19, the canopy space is dynamically divided into several independent three-dimensional operation sub-regions corresponding to the number of air outlets 19, and the volume of each sub-region is calculated and used as the basis for air volume calculation.

[0038] S3. Contouring command generation: Based on the maximum two-dimensional canopy profile extracted in step S2 and the real-time pose of the sprayer, the contour curve corresponding to each robotic arm working segment is segmented and linearized. Based on this, the translation distance and target angle of each joint of each robotic arm working segment are calculated, and the contouring motion command that drives the robotic arm working segment to conform to the canopy contour is generated.

[0039] The specific steps are as follows: S31. Establish a two-dimensional local coordinate system with the midpoint of the central translation arm 7 as the origin. The X-axis is the horizontal axis, which is perpendicular to the forward direction of the sprayer and points to the canopy on the working side. The Y-axis is vertically upward. Extract the contour point set from this two-dimensional profile and retain the single-sided point set facing the working side of the sprayer.

[0040] S32. Based on the length ratio of the central translation arm 7, the upper proximal rotation arm 8, the lower proximal rotation arm 9, the upper distal rotation arm 10, and the lower distal rotation arm 11, the single-sided contour is divided into five continuous segments from top to bottom, and a contour point set for each segment is established. The mapping relationship between the corresponding robotic arm and the robotic arm.

[0041] S33. For the contour point set corresponding to each robotic arm segment, the least squares method is used to perform linear regression fitting to obtain the optimal fitting line for each segment, which serves as the benchmark for subsequent robotic arm posture adjustment. Among them, the central translation arm 7 only performs horizontal movement, and its fitting line is calculated based solely on the X-axis coordinate of the corresponding contour point set. The fitting lines of the other rotating robotic arms need to be calculated by combining the X-axis and Y-axis coordinates.

[0042] S34. By translating and rotating each robotic arm segment, the robotic arm axis is kept parallel to the corresponding fitted straight line, and the distance between them is equal to the preset working distance d, so as to achieve posture matching between each robotic arm segment and the canopy contour; among them, the central translation arm 7 is adjusted by horizontal linear movement, and the expression for its translation distance D is: In the formula, N is the number of points corresponding to the robotic arm, and d is the preset working distance. Let x be the x-coordinate of the i-th contour point of the robotic arm.

[0043] The remaining rotary robotic arms rotate around their respective hinge points to achieve posture matching, such as... Figure 4 The simulated shape effect shown has a rotation angle. The expression is: In the formula, Let be the ordinate of the i-th contour point of the robotic arm.

[0044] S4. Adaptive air volume and wind speed calculation based on canopy characteristics: The system first calculates the theoretical total air volume required for spraying operations based on the canopy characteristic parameters of the fruit trees on both sides of the sprayer. Then, according to the volume ratio of the sub-regions corresponding to each air outlet 19, the theoretical total air volume is dynamically distributed to each air outlet 19 proportionally. Finally, the corresponding target wind speed is calculated based on the area of ​​the air outlet 19, so as to realize differentiated and precise air delivery based on canopy characteristics and sub-region requirements, ensuring that the liquid penetrates the canopy evenly and fully, and improving the quality and efficiency of spraying operations.

[0045] The expression for the total air volume is: The expression for the air outlet wind speed is: In the formula, The total air volume required for the canopy. Canopy height, The number of air outlets. The diameter of the air outlet. The speed at which the sprayer travels. Let i be the distance from the i-th air outlet to the fruit tree canopy. The loss coefficient of air volume, The initial velocity to reach the canopy surface, Let be the air velocity at the i-th air outlet.

[0046] The value of K varies depending on factors such as meteorological conditions, crop variety, and foliage density, and generally ranges from 1.3 to 1.8. Based on practical experience in agricultural plant protection, the baseline wind speed values ​​for different crop varieties are as follows: 9–10 m / s for apple trees, 7–8 m / s for pear trees, and 8–9 m / s for grapes. It should be noted that the above values ​​are merely illustrative and can be adjusted according to the specific crop variety, tree age, growth stage, and local climate conditions in practical applications.

[0047] S5. Fan speed control: Based on the theoretical total air volume calculated in step S4 and the target wind speed distribution of each air outlet 19, the controller 4 adjusts the speed of the fan 14 to achieve a stable output of the theoretical total air volume and match the wind speed of each air outlet 19.

[0048] S6. Closed-loop feedback adjustment: The actual rotation angle of the robotic arm is collected in real time by the angle sensors of each joint, and the measured wind speed value of each air outlet is obtained by the wind speed sensor 22. The measured values ​​are compared with the target angle and target wind speed set in steps S3 and S4 to calculate the angle error and air volume error. Based on the error value, the speed of the robotic arm joint actuator and the fan is corrected in real time by the control algorithm to dynamically maintain the stable operation and precise operation of the system, and realize the closed-loop adjustment of the operation process.

[0049] Finally, it should be noted that any parts of this invention not described in detail are prior art. Those skilled in the art will understand that the above descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. An adaptive wind volume and direction control method based on fruit tree canopy characteristics, characterized in that, Includes the following steps: S1. System initialization and self-test: After the system starts, the controller (4) resets each actuator to the preset safe position and performs self-calibration on all sensors. At the same time, the controller (4) establishes communication with each module and performs stability verification. After confirming that each component is in normal condition, it controls the sprayer to travel to the start position of the operation. S2, Canopy 3D Information Perception and Feature Extraction: The canopy of the target fruit tree is scanned by a 3D lidar (3) and the 3D point cloud data of the canopy is collected; the canopy point cloud data is processed by the controller (4) and the maximum two-dimensional canopy profile is constructed perpendicular to the forward direction of the sprayer. The maximum two-dimensional canopy profile is used as the reference for the robotic arm to follow the shape; at the same time, according to the preset air outlet (19) layout, the canopy space is dynamically divided into several independent 3D operation sub-regions corresponding to the number of air outlets (19), the volume of each sub-region is calculated and used as the basis for air volume calculation; S3. Contouring command generation: Based on the maximum two-dimensional canopy profile extracted in step S2 and the real-time pose of the sprayer, the contour curve corresponding to each robotic arm working segment is segmented and linearized. Based on this, the translation distance and target angle of each joint of each robotic arm working segment are calculated, and the contouring motion command that drives the robotic arm working segment to conform to the canopy contour is generated. S4. Adaptive air volume and wind speed calculation based on canopy features: The system first calculates the theoretical total air volume required for spraying operation based on the canopy feature parameters of the fruit trees on both sides of the sprayer. Then, according to the volume ratio of the sub-regions corresponding to each air outlet (19), the theoretical total air volume is dynamically allocated to each air outlet (19) in proportion. Then, the corresponding target wind speed is calculated based on the area of ​​the air outlet (19). S5. Fan speed control: The controller (4) adjusts the fan speed (14) based on the theoretical total air volume calculated in step S4 and the target wind speed distribution of each air outlet (19) to achieve stable output of theoretical total air volume and matching of wind speed of each air outlet (19). S6. Closed-loop feedback adjustment: The actual rotation angle of the robotic arm is collected in real time by the angle sensors of each joint of the robotic arm, and the wind speed is measured at each air outlet (19) by the wind speed sensor (22). The measured values ​​are compared with the target angle and target wind speed set in steps S3 and S4, and the angle error and air volume error are calculated. Based on the error value, the speed of the robotic arm joint driver and the fan (14) is corrected in real time by the control algorithm to dynamically maintain the stable operation and precise operation of the system, and realize the closed-loop adjustment of the operation process.

2. The adaptive wind volume and direction control method based on fruit tree canopy characteristics according to claim 1, characterized in that, The robotic arm in step S3 includes a central translation arm (7) mounted on the mounting platform (5), an upper proximal rotating arm (8) and a lower proximal rotating arm (9) connected to both ends of the central translation arm (7), an upper distal rotating arm (10) connected to the upper proximal rotating arm (8), and a lower distal rotating arm (11) connected to the lower proximal rotating arm (9); the controller (4) calculates the translation distance of the central translation arm (7) and the rotation angles of the upper proximal rotating arm (8), the lower proximal rotating arm (9), the upper distal rotating arm (10), and the lower distal rotating arm (11).

3. The adaptive wind volume and direction control method based on fruit tree canopy characteristics according to claim 1 or 2, characterized in that, The specific steps for generating the contouring command in step S3 are as follows: S31. Establish a two-dimensional local coordinate system with the midpoint of the central translation arm (7) as the origin. The X-axis is the horizontal axis, which is perpendicular to the forward direction of the sprayer and points to the canopy on the working side. The Y-axis is vertically upward. Extract the contour point set from this two-dimensional profile and retain the single-sided point set facing the working side of the sprayer. S32. Based on the length ratio of the central translation arm (7), the upper proximal rotating arm (8), the lower proximal rotating arm (9), the upper distal rotating arm (10), and the lower distal rotating arm (11), the single-sided contour is divided into five continuous segments from top to bottom, and the mapping relationship between the contour point set of each segment and the corresponding robotic arm is established. S33. For the contour point set corresponding to each robotic arm segment, the least squares method is used to perform linear regression fitting to obtain the optimal fitting line of each segment, which serves as the benchmark for subsequent robotic arm posture adjustment. Among them, the central translation arm (7) only performs horizontal movement, and its fitting line is calculated based only on the X-axis coordinate of the corresponding contour point set. The fitting lines of the other rotating robotic arms need to be calculated by combining the X-axis and Y-axis coordinates. S34. By translating and rotating each robotic arm segment, the robotic arm axis is kept parallel to the corresponding fitted straight line, and the distance between them is equal to the preset working distance. This is to achieve posture matching between each robotic arm segment and the canopy contour.

4. The adaptive wind volume and direction control method based on fruit tree canopy characteristics according to claim 3, characterized in that, The central translation arm (7) mentioned in step S34 is adjusted by horizontal linear movement, and its translation distance is... The expression is: In the formula, N is the number of points corresponding to the robotic arm. Preset the distance for the operation. Let x be the x-coordinate of the i-th contour point of the robotic arm; The remaining rotary robotic arms rotate around their respective hinge points to complete the attitude matching, and the expression for their rotation angle θ is: In the formula, Let be the ordinate of the i-th contour point of the robotic arm.

5. The adaptive wind volume and direction control method based on fruit tree canopy characteristics according to claim 1, characterized in that, The expression for the total air volume in step S4 is: The expression for the air outlet wind speed is: In the formula, The total air volume required for the canopy. Canopy height, The number of air outlets. The diameter of the air outlet. The speed at which the sprayer travels. Let i be the distance from the i-th air outlet to the fruit tree canopy. This is the air volume loss coefficient; The initial velocity to reach the canopy surface, Let be the air velocity at the i-th air outlet.

6. An adaptive wind volume and direction control system based on fruit tree canopy characteristics, used to implement the method described in any one of claims 1 to 5, characterized in that, include: The mobile chassis (1), three-dimensional lidar (3), controller (4), contouring module, air delivery module and spraying module; the three-dimensional lidar (3) is installed at the front end of the mobile chassis (1) and is used to acquire the characteristic information of the fruit tree canopy in real time; the controller (4) is fixed in the electrical control box above the mobile chassis (1) and is electrically connected to the mobile chassis (1), three-dimensional lidar (3), contouring module, air delivery module and spraying module respectively; the contouring module is installed at the rear end of the mobile chassis (1) and includes a mounting platform (5) and a robotic arm arranged symmetrically on the left and right; The air delivery module includes a fan (14) fixedly installed on the mobile chassis (1), a pressure stabilizing manifold (15) connected to the fan (14), and an air delivery channel (16) set on the air outlet side of the pressure stabilizing manifold (15); the spray module includes a medicine tank (23), a medicine pump (24) and multiple nozzles (25) connected in sequence through a medicine delivery pipeline. The medicine tank (23) is fixed on the mobile chassis (1), and the nozzles (25) are set at the airflow outlet of the air outlet (19), and the spraying direction of the nozzles (25) is consistent with the air outlet direction of the air outlet (19).

7. The adaptive wind volume and direction control system based on fruit tree canopy characteristics according to claim 6, characterized in that, Each set of robotic arms includes a central translation arm (7), an upper proximal rotating arm (8), a lower proximal rotating arm (9), an upper distal rotating arm (10), and a lower distal rotating arm (11). The central translation arm (7) is vertically mounted on the mounting platform (5) and can be raised and lowered relative to the mounting platform (5). The front ends of the upper proximal rotating arm (8) and the lower proximal rotating arm (9) are respectively hinged to the upper and lower ends of the central translation arm (7). Driven by a motor (12), it can rotate around the hinge point toward the canopy. The upper distal rotating arm (10) and the lower distal rotating arm (11) are respectively hinged to the ends of their corresponding upper proximal rotating arm (8) and lower proximal rotating arm (9). Driven by upper and lower electric push rods (13), it can rotate around the hinge point further toward the canopy. The ends of the upper distal rotating arm (10) and the lower distal rotating arm (11) are fixedly connected to the air delivery module.

8. The adaptive wind volume and direction control system based on fruit tree canopy characteristics according to claim 7, characterized in that, The upper proximal rotating arm (8) and the lower proximal rotating arm (9) have the same length, and the upper distal rotating arm (10) and the lower distal rotating arm (11) have the same length.

9. The adaptive airflow and direction control system based on fruit tree canopy characteristics according to claim 6, characterized in that, The air delivery channel (16) includes a diversion pipe (18) and an air outlet (19). The air outlet (19) is equipped with an adjustable flow guiding mechanism (21) driven by a servo motor (20), and a wind speed sensor (22) is installed at the outlet.

10. The adaptive wind volume and direction control system based on fruit tree canopy characteristics according to claim 6, characterized in that, The pressure stabilizing collector (15) is equipped with a flow equalization plate (17) for evenly distributing airflow to each air delivery channel (16).

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