Parallel mechanism precise spraying robot and control method thereof

Abstract

The invention provides a parallel mechanism precise spraying robot and a control method thereof, and relates to agricultural robots. A water tank; each parallel executing mechanism comprises an upper platform, a lower platform, a nozzle and a three-connecting-rod assembly, each connecting rod assembly comprises a first driving motor, a first connecting rod and two second connecting rods, one end of the first connecting rod is connected with the first driving motor, and the other end of the first connecting rod is rotatably connected with the upper ends of the two second connecting rods; the lower ends of the two second connecting rods are rotatably connected with the lower platform. The nozzle is arranged at the bottom of the lower platform. A depth camera; and the controller is used for acquiring an image of a to-be-weeded area in front of the moving trolley, identifying weeds and determining the positions of the weeds, and controlling the first driving motors to rotate to drive the lower platform to move, so that the nozzles are aligned with the weeds. The weeding robot has the beneficial effects that the spraying precision of the nozzle can be accurately controlled, the robot can automatically and accurately spray and weed, and the efficiency and precision of weeding operation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural robots, and in particular, to a parallel mechanism precision spraying robot and a control method thereof. Background Art

[0002] In recent years, with the rapid development of agricultural production, the problem of weeds in the fields has become increasingly serious. At present, the main way to remove weeds from crops is chemical weeding, and herbicides are the simplest and most efficient way to remove weeds. However, chemical weeding also brings some hazards. For example, during the spraying process, surrounding crops are damaged by the herbicide drifting with the wind and the volatilization of the liquid medicine droplets during the spraying process. The traditional method of using herbicides without discrimination over a large area is difficult to meet the needs of current agricultural production. Building an intelligent precision spraying weeding robot has become the optimal solution to solve the weeding problem at present. Weeding robots generally control the herbicide spraying actuator to spray herbicides on weeds. However, the movement accuracy of the herbicide spraying actuator of current weeding robots is relatively low, and the spraying accuracy of herbicides is difficult to strictly control, which easily causes accidental injury to crops. Summary of the Invention

[0003] In view of this, in order to solve the problem of relatively low movement accuracy of the herbicide spraying actuator of current weeding robots, embodiments of the present invention provide a parallel mechanism precision spraying robot and a control method thereof.

[0004] Embodiments of the present invention provide a parallel mechanism precision spraying robot, including:

[0005] A mobile trolley;

[0006] A water tank, which is arranged on the mobile trolley;

[0007] At least one parallel actuator, each of the parallel actuators includes an upper platform, a lower platform, a nozzle and a three-link assembly. Among them, the upper platform is arranged at the bottom of the water tank, the lower platform is arranged below the upper platform, and the three link assemblies are circumferentially arranged around the upper platform and the lower platform. Each link assembly includes a first driving motor, a first link and two second links. The first driving motor is arranged on the upper platform. One end of the first link is connected to the first driving motor, and the other end is rotatably connected to the upper ends of the two second links. The lower ends of the two second links are respectively rotatably connected to the lower platform. The nozzle is arranged at the bottom of the lower platform and is connected to the water tank through a pipeline;

[0008] A depth camera, which is arranged at the bottom of the water tank, and the camera is used to collect images of the weeding area in front of the mobile trolley;

[0009] And a controller, which is respectively connected to the depth camera and each of the first drive motors, is configured to obtain an image of the weed removal area in front of the mobile trolley, identify weeds and determine the positions of the weeds according to the image of the weed removal area, and control each of the first drive motors to rotate to drive the lower platform to move, so that the nozzle is aligned with the weeds.

[0010] Further, the link assembly further includes a third link, the middle of the third link is rotatably connected to one end of the first link, and both ends of the third link are respectively rotatably connected to the upper ends of the two second links.

[0011] Further, the upper platform is Y-shaped and includes three fixed beams connected at one point, and the included angle between any two adjacent fixed beams is the same. The first drive motor of each link assembly is installed on one side of one of the fixed beams.

[0012] Further, the lower platform is a regular hexagon, and the lower ends of the two second links of each link assembly are respectively hinged to two adjacent vertices of the lower platform.

[0013] Further, the nozzle is installed at the center of the bottom of the lower platform, and the upper end of the nozzle penetrates through the lower platform and is connected to the water tank through a hose.

[0014] Further, the mobile trolley includes a frame and two wheel assemblies. The water tank is installed on the frame, and the two wheel assemblies are respectively installed on both sides of the frame. Each wheel assembly includes a suspension, two wheels, two wheel frames, two spring shock absorbers and two second drive motors. Each wheel and a second drive motor are installed at the lower end of one of the wheel frames, and the second drive motor is connected to the wheel to drive the wheel to rotate. The upper ends of the two wheel frames are respectively rotatably connected to both ends of the lower part of the suspension, the two wheel frames are arranged in a V-shape, and the upper ends of the two spring shock absorbers are respectively rotatably connected to both ends of the upper part of the suspension.

[0015] Further, the suspension is an isosceles trapezoid with a wider upper part and a narrower lower part. The upper ends of the two wheel frames are respectively rotatably connected to the two vertices of the lower part of the suspension, and the upper ends of the two spring shock absorbers are respectively rotatably connected to the two vertices of the upper part of the suspension.

[0016] Further, triangular connection frames are provided on both sides of the frame. The bottom of the connection frame is hinged to the suspension, and the frame is provided with two stabilizing rods. The upper ends of the two stabilizing rods are respectively hinged to the two vertices of the rear part of the frame, and the lower ends are respectively hinged to the rear ends of the upper parts of the two suspensions.

[0017] In addition, an embodiment of the present invention further provides a control method for the above-mentioned parallel mechanism precision spraying robot, including the following steps:

[0018] S1. The controller obtains an image of the weed removal area in front of the mobile cart;

[0019] S2. The controller inputs the image of the weed removal area into the seedling and weed recognition system to identify weeds and determine the positions of the weeds. Specifically, it includes: pre-collecting pictures of crops and weeds, preprocessing the collected pictures to expand the data set and enhance the robustness of the model, using the YOLO V5 model to extract the features of crops and weeds from the preprocessed pictures, and respectively establishing databases for crop features and weed features according to the extracted features to form the seedling and weed recognition system. Then, input the image of the weed removal area into the seedling and weed recognition system for comparison to identify the weeds, and further determine the positions of the weeds;

[0020] S3. The controller controls each of the second drive motors to rotate forward or backward respectively, so that the first link of each link assembly moves in different directions, driving the lower platform to lift and move horizontally, so as to align the nozzle with the weeds.

[0021] Further, the parallel mechanism precision spraying robot further includes a lidar disposed on the water tank, the controller is connected to the lidar, and the control method further includes:

[0022] The controller obtains map data, and the map data includes aerial image data of the weed removal area, an image of the weed removal area, and radar data;

[0023] The controller optimizes the map data by using the SLAM algorithm, and divides the map data into four layers: plot information layer, obstacle layer, weed removal operation information layer, and dynamic perception layer. The plot information layer includes plot boundaries, entrances and exits, and tractor roads. The obstacle layer includes inherent obstacles. The operation information layer includes map information for the weeding machine to remove weeds. The dynamic perception layer is the surrounding environment information obtained by fusing the image of the weed removal area and radar data;

[0024] The controller uses the A* algorithm to find the shortest path from the current position of the parallel mechanism precision spraying robot to the target position in the weed removal area in the optimized map data;

[0025] The controller controls the mobile cart to walk along the shortest path.

[0026] The beneficial effects brought by the technical solution provided by the embodiment of the present invention are:

[0027] 1. A parallel mechanism precision spraying robot and its control method of the present invention. The parallel execution mechanism drives the multi-degree-of-freedom movement of the lower platform through the cooperation of multiple link assemblies, that is, drives the multi-degree-of-freedom movement of the nozzle on the lower platform, improving the movement accuracy of the nozzle. By controlling the rotation of the first drive motor of each link assembly, the movement of the nozzle can be controlled, and precise point spraying at different heights and positions can be realized. Thus, the spraying accuracy of the herbicide can be precisely controlled, enabling the robot to automatically and precisely spray and weed, improving the efficiency and accuracy of the weeding operation, and reducing the usage amount of the herbicide and the phytotoxicity suffered by the crops.

[0028] 2. A parallel mechanism precision spraying robot and its control method of the present invention. By processing the image of the weeding area in front of the mobile cart to identify weeds, and controlling the movement of each link assembly according to the position of the weeds, the nozzle is precisely aligned with the weeds, and the action and posture of the nozzle are adjusted, enabling the robot to automatically and precisely spray and weed, quickly and accurately identify and remove weeds, and minimize the phytotoxicity suffered by the crops.

[0029] 3. A parallel mechanism precision spraying robot and its control method of the present invention. The SLAM algorithm is used to optimize the map data, which includes a plot information layer, an obstacle layer, a weeding operation information layer, and a dynamic perception layer. Combining the weeding operation information, an efficient and non-repetitive operation path is realized, enabling the parallel execution mechanism to flexibly execute the weeding task, improving the efficiency and accuracy.

[0030] 4. A parallel mechanism precision spraying robot of the present invention. The mobile cart moves smoothly. The two wheels of each wheel assembly cooperate with each other, and the wheel height can be adjusted adaptively, making the vehicle frame stable and flexible. Thus, it can easily meet the requirements of different terrains and operating environments, enabling the robot to walk smoothly in the rough fields. Keeping the vehicle frame stable is beneficial to accurately controlling the movement accuracy of the nozzle and improving the spraying accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the three-dimensional view of a parallel mechanism precision spraying robot of the present invention Figure 1 ;

[0032] Figure 2 is the three-dimensional view of a parallel mechanism precision spraying robot of the present invention Figure 2 ;

[0033] Figure 3 is the front view of the wheel assembly;

[0034] Figure 4 is the three-dimensional view of the wheel assembly;

[0035] Figure 5 is the schematic diagram of the parallel execution mechanism;

[0036] Figure 6 It is a schematic diagram of a connecting rod assembly.

[0037] In the figure: 1. Moving trolley; 101. Frame; 102. Wheel assembly; 103. Connecting frame; 104. Stabilizing rod; 105. Suspension; 106. Wheel carrier; 107. Spring shock absorber; 108. Wheel; 109. Second driving motor; 2. Water tank; 3. Parallel actuator; 301. Upper platform; 302. Lower platform; 303. Connecting rod assembly; 304. First driving motor; 305. First connecting rod; 306. Second connecting rod; 307. Third connecting rod; 308. Hose; 4. Depth camera; 5. LiDAR. Detailed implementation manners

[0038] To make the objectives, technical solutions and advantages of the present invention clearer, the following will further describe the embodiments of the present invention with reference to the accompanying drawings. The following introduces a relatively better one among multiple possible embodiments of the present invention, aiming to provide a basic understanding of the present invention, but not aiming to identify the key or decisive elements of the present invention or limit the scope to be protected.

[0039] In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0040] For technologies, methods and devices known to those of ordinary skill in the relevant art, detailed discussions may not be made, but where appropriate, the said technologies, methods and devices should be regarded as part of the specification.

[0041] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings. At the same time, it should be understood that, for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships.

[0042] In the description of the present invention, it should be noted that the circuits, electronic components and modules involved in the present invention are all prior art, and those skilled in the art can fully implement them without further elaboration. The content protected by the present invention does not involve improvements to the internal structure and methods either.

[0043] It should be further noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] Please refer to Figure 1 and 2 , an embodiment of the present invention provides a parallel mechanism precision spraying robot, which is applied to crop weeding, such as field crop weeding, and mainly includes a mobile trolley 1, a water tank 2, at least one parallel actuator 3, a depth camera 4, a lidar 5 and a controller.

[0045] The mobile trolley 1 is used to carry the parallel mechanism precision spraying robot to walk in the field. The mobile trolley 1 generally selects a four-wheel drive trolley, which can make the parallel mechanism precision spraying robot walk stably and flexibly.

[0046] As Figure 3 and 4 shown, in this embodiment, the mobile trolley 1 includes a frame 101 and two wheel assemblies 102. The water tank 2 is installed on the frame 101, and the two wheel assemblies 102 are respectively installed on both sides of the frame 101. Here, the two wheel assemblies 102 are symmetrically arranged on both sides of the frame 101.

[0047] Each wheel assembly 102 specifically includes a suspension 105, two wheels 108, two wheel frames 106, two spring shock absorbers 107 and two second drive motors 109. Each wheel 108 and a second drive motor 109 are installed at the lower end of a wheel frame 106, and the second drive motor 109 is connected to the wheel 108 to drive the wheel 108 to rotate. The wheel frame 106 is inclined, the two wheel frames 106 are arranged in a V shape, the wheel 108 is rotatably installed at the lower end of the wheel frame 106, and the second drive motor 109 is located inside the wheel 108 and installed at the lower end of the wheel frame 106. The second drive motor 109 generally selects a servo motor, and the wheel 108 can be driven to rotate by the second drive motor 109.

[0048] The upper ends of the two wheel carriers 106 are respectively rotatably connected to the two ends of the lower part of the suspension 105, and the upper ends of the two spring shock absorbers 107 are respectively rotatably connected to the two ends of the upper part of the suspension 105. The suspension 105 is an isosceles trapezoid that is wider at the top and narrower at the bottom. The upper ends of the two wheel carriers 106 are respectively rotatably connected to the two vertices of the lower part of the suspension 105, and the upper ends of the two spring shock absorbers 107 are respectively rotatably connected to the two vertices of the upper part of the suspension 105. Here, the wheel carrier 106 and the suspension 105 are connected by hinges, and the spring shock absorber 107 and the suspension 105 are also connected by hinges.

[0049] On both sides of the vehicle frame 101, triangular connecting frames 103 are provided. The bottom of the connecting frame 103 is hinged to the suspension 105. One side of the connecting frame 103 is arranged upwards and connected to one side of the vehicle frame 101, and the top angle opposite to this side on the connecting frame 103 is arranged downwards and hinged to the suspension 105.

[0050] Moreover, the vehicle frame 101 is provided with two stabilizer bars 104. The upper ends of the two stabilizer bars 104 are respectively hinged to the two vertices at the rear of the vehicle frame 101, and the lower ends are respectively hinged to the rear ends of the upper parts of the two suspensions 105. Here, the two ends of each stabilizer bar 104 are respectively ball-jointed to the vehicle frame 101 and the suspension 105.

[0051] When the mobile trolley 1 travels on rough ground, the heights of the two wheels 108 of each wheel assembly 102 can be adaptively adjusted so that the two wheels 108 are at different heights, forming a stable support for the vehicle frame 101, making the vehicle frame 101 stable and flexible, and thus can easily meet the requirements of different terrains and working environments.

[0052] The water tank 2 is arranged on the mobile trolley 1. The water tank 2 is used to store the herbicide solution to be sprayed. The shape of the water tank 2 can be flexibly set according to the actual application scenario. In this embodiment, for example, the shape of the water tank 2 is set to be approximately a cuboid. The four corners of the bottom of the water tank 2 are exactly supported and fixed on the four corners of the vehicle frame 101.

[0053] The parallel actuator 3 is used to adjust the spraying position of the herbicide solution. The number of the parallel actuators 3 can be flexibly selected according to the actual weeding scenario. Generally, the number of the parallel actuators 3 is set to be multiple, and the parallel actuators 3 are arranged in a horizontal row. In this embodiment, for example, the number of the parallel actuators 3 is set to be two.

[0054] Such as Figure 5 and 6As shown, each of the parallel actuators 3 includes an upper platform 301, a lower platform 302, a nozzle, and a three-link assembly 303. The upper platform 301 is disposed at the bottom of the water tank 2, and the upper platform 301 is horizontally and fixedly disposed below the water tank 2. The lower platform 302 is disposed below the upper platform 301, and the area of the lower platform 302 is generally smaller than that of the upper platform 301.

[0055] The three link assemblies 303 are circumferentially disposed around the upper platform 301 and the lower platform 302. The upper end of each link assembly 303 is connected to the upper platform 301, and the lower end is connected to the lower platform 302. Each link assembly 303 includes a first driving motor 304, a first link 305, and two second links 306.

[0056] The first driving motor 304 is disposed on the upper platform 301. Specifically, the upper platform 301 is Y-shaped and includes three fixed beams connected at one point, and the angle between any two adjacent fixed beams is the same. The first driving motor 304 of each link assembly 303 is installed on one side of a fixed beam, and each link assembly 303 is located between two adjacent fixed beams of the upper platform 301.

[0057] One end of the first link 305 is connected to the first driving motor 304, and the other end is rotatably connected to the upper ends of the two second links 306. In this embodiment, the link assembly 303 further includes a third link 307. The third link 307 passes through the outer end of the first link 305, and the middle of the third link 307 is rotatably connected to one end of the first link 305. The two ends of the third link 307 are respectively rotatably connected to the upper ends of the two second links 306, and here the two ends of the third link 307 are respectively ball-jointedly connected to the upper ends of the two second links 306.

[0058] The lower ends of the two second links 306 are respectively rotatably connected to the lower platform 302. The lower platform 302 is a regular hexagon. The lower ends of the two second links 306 of each link assembly 303 are respectively hinged to two adjacent vertices of the lower platform 302. In this embodiment, the lower end of the second link 306 is ball-jointedly connected to the vertex of the lower platform 302. In this way, the six second links 306 of the three link assemblies 303 are respectively hinged to the six vertices of the lower platform 302, and the lower platform 302 can be driven to move with multiple degrees of freedom through the three link assemblies 303.

[0059] The nozzle is arranged at the bottom of the lower platform 302 and is connected to the water tank 2 through a pipeline. Specifically, the nozzle is installed at the center of the bottom of the lower platform 302, and the upper end of the nozzle penetrates through the lower platform 302 and is connected to the water tank 2 through a hose 308.

[0060] The first driving motor 304 generally selects a stepping motor. The first driving motor 304 can drive the first connecting rod 305 to rotate. When the first connecting rod 305 rises or falls, it can drive the two second connecting rods 306 to move, thereby driving the lower platform 302 to move. The lower platform 302 drives the nozzle to move, and can accurately move to the position to be sprayed.

[0061] The depth camera 4 is arranged at the bottom of the water tank 2, near the center of the front end of the water tank 2. The depth camera 4 is arranged facing forward, and the depth camera 4 can collect the image of the area to be weeded in front of the mobile trolley 1. The lidar 5 is arranged on the top of the water tank 2, and the lidar 5 can collect the radar data in front of the mobile trolley 1.

[0062] The controller is connected to the three first driving motors 304, the four second driving motors 109, the depth camera 4 and the lidar 5. When this parallel mechanism precision spraying robot is weeding crops, the controller controls the four second driving motors 109 to rotate to control the mobile trolley 1 to walk in the weeding area. And the controller obtains the image of the area to be weeded in front of the mobile trolley 1, identifies the weeds and determines the positions of the weeds according to the image of the area to be weeded, and controls each first driving motor 304 to rotate to drive the lower platform 302 to move, so that the nozzle is aligned with the weeds and the nozzle moves to the position to be sprayed, thereby realizing accurate point spraying at different heights and different positions.

[0063] In addition, the embodiment of the present invention also provides a control method for the above-mentioned parallel mechanism precision spraying robot, including the following steps:

[0064] The controller controls the mobile trolley 1 to walk in the weeding area. Specifically:

[0065] The controller obtains map data, and the map data includes aerial image data of the weeding area, images of the area to be weeded and radar data. The aerial image data is obtained by aerial photography of the weeding area by an unmanned aerial vehicle. The image of the area to be weeded is obtained by the depth camera 4 photographing the image in front of the mobile trolley 1, and the radar data is obtained by the lidar 5 scanning in front of the mobile trolley 1.

[0066] The controller optimizes the map data using the SLAM (Simultaneous Localization and Mapping) algorithm, and divides the map data into four layers: the plot information layer, the obstacle layer, the weeding operation information layer, and the dynamic perception layer. The plot information layer includes plot boundaries, entrances and exits, and tractor roads, etc. The obstacle layer includes inherent field obstacles such as utility poles. The operation information layer includes map information for the weeding machine to perform weeding. The dynamic perception layer is the surrounding environment information obtained by fusing the images of the area to be weeded and radar data.

[0067] The controller uses the A* algorithm to find the shortest path from the current position of the parallel mechanism precision spraying robot to the target position in the weeding area in the optimized map data;

[0068] The controller controls each of the second drive motors 109 to rotate, thereby controlling the mobile trolley 1 to travel along the shortest path.

[0069] And during the travel of the mobile trolley 1, the controller controls the parallel execution mechanism 3 to adjust its position to spray herbicides on the weeds between the crops in the weeding area. Specifically:

[0070] S1. The controller acquires the image of the area to be weeded in front of the mobile trolley 1;

[0071] S2. The controller inputs the image of the area to be weeded into the seedling and weed recognition system to identify the weeds and determine the positions of the weeds. Specifically, it includes:

[0072] Pre-collect pictures of crops and weeds to ensure high-quality and clear pictures;

[0073] Preprocess the collected pictures, such as scaling, cropping, flipping, etc., to expand the dataset and enhance the robustness of the model;

[0074] Use the YOLO V5 model to extract the features of crops and weeds from the preprocessed pictures;

[0075] According to the extracted features, establish databases for crop features and weed features respectively to form the seedling and weed recognition system;

[0076] Input the image of the area to be weeded collected in real time into the seedling and weed recognition system for comparison to identify the weeds and further determine the positions of the weeds.

[0077] S3. The controller respectively controls the forward or reverse rotation of each of the second drive motors 109, so that the first link 305 of each of the link assemblies 303 rotates towards different directions, to pull the second links 306 of the three link assemblies 303 to move in different directions. The second links 306 of the three link assemblies 303 pull the lower platform 302 to lift and move laterally. Specifically, the lower platform 302 can not only lift, but also move in six directions laterally. In this way, the movement of the lower platform 302 can be accurately controlled to control the movement of the nozzle, so that the nozzle can accurately align with the weeds.

[0078] In this article, the orientation words such as front, back, up, and down are defined based on the positions of the components in the drawings and the positions of the components relative to each other, only for the sake of clarity and convenience in expressing the technical solution. It should be understood that they are relative concepts and can change accordingly according to different usage and placement methods. The use of the orientation words should not limit the scope of protection claimed in this application.

[0079] Without conflict, the above embodiments and the features in the embodiments in this article can be combined with each other. The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A parallel mechanism precision spraying robot, characterized in that, Comprising: A mobile trolley; A water tank, which is arranged on the mobile trolley; At least one parallel execution mechanism, each of the parallel execution mechanisms includes an upper platform, a lower platform, a nozzle and a three-link assembly. Wherein, the upper platform is arranged at the bottom of the water tank, the lower platform is arranged below the upper platform, and the three link assemblies are circumferentially arranged around the upper platform and the lower platform. Each link assembly includes a first driving motor, a first link and two second links. The first driving motor is arranged on the upper platform. One end of the first link is connected to the first driving motor, and the other end is rotatably connected to the upper ends of the two second links. The lower ends of the two second links are respectively rotatably connected to the lower platform. The nozzle is arranged at the bottom of the lower platform and is connected to the water tank through a pipeline; A depth camera, which is arranged at the bottom of the water tank, and the camera is used to collect images of the weeding area in front of the mobile trolley; And a controller, which is respectively connected to the depth camera and each of the first driving motors, is used to obtain images of the weeding area in front of the mobile trolley, identify weeds and determine the positions of weeds according to the images of the weeding area, and control each of the first driving motors to rotate to drive the lower platform to move so that the nozzle is aligned with the weeds.

2. The precision spraying robot with a parallel mechanism according to claim 1, characterized in that: The link assembly further includes a third link, the middle of the third link is rotatably connected to one end of the first link, and the two ends of the third link are respectively rotatably connected to the upper ends of the two second links.

3. The precision spraying robot with a parallel mechanism according to claim 1, characterized in that: The upper platform is Y-shaped, including three fixed beams connected at one point, and the angle between any two adjacent fixed beams is the same. The first driving motor of each link assembly is installed on one side of a fixed beam.

4. The precision spraying robot with a parallel mechanism according to claim 1, characterized in that: The lower platform is a regular hexagon, and the lower ends of the two second links of each link assembly are respectively hinged to two adjacent vertices of the lower platform.

5. The precision spraying robot with a parallel mechanism according to claim 4, characterized in that: The nozzle is installed at the center of the bottom of the lower platform, and the upper end of the nozzle penetrates through the lower platform and is connected to the water tank through a hose.

6. The precise spraying robot with a parallel mechanism according to claim 1, characterized in that: The mobile trolley includes a frame and two wheel assemblies. The water tank is installed on the frame, and the two wheel assemblies are respectively installed on both sides of the frame. Each wheel assembly includes a suspension, two wheels, two wheel frames, two spring shock absorbers and two second driving motors. Each wheel and a second driving motor are installed at the lower end of a wheel frame, and the second driving motor is connected to the wheel to drive the wheel to rotate. The upper ends of the two wheel frames are respectively rotatably connected to both ends of the lower part of the suspension. The two wheel frames are arranged in a V shape, and the upper ends of the two spring shock absorbers are respectively rotatably connected to both ends of the upper part of the suspension.

7. The precision spraying robot with a parallel mechanism according to claim 6, characterized in that: The suspension is an isosceles trapezoid with a wider upper part and a narrower lower part. The upper ends of the two wheel frames are respectively rotatably connected to the two vertices of the lower part of the suspension, and the upper ends of the two spring shock absorbers are respectively rotatably connected to the two vertices of the upper part of the suspension.

8. The precision spraying robot with a parallel mechanism according to claim 6 or 7, characterized in that: Triangular connecting frames are arranged on both sides of the frame. The bottom of the connecting frame is hinged to the suspension. The frame is provided with two stabilizing rods. The upper ends of the two stabilizing rods are respectively hinged to the two vertices of the rear part of the frame, and the lower ends are respectively hinged to the rear ends of the upper parts of the two suspensions.

9. The control method of a parallel mechanism precision spraying robot according to any one of claims 1-8, characterized in that , including the following steps: S1. The controller acquires the image of the weeding area in front of the mobile cart; S2. The controller inputs the image of the weeding area into the seedling and weed recognition system to identify weeds and determine the positions of the weeds. Specifically, it includes: pre-collecting pictures of crops and weeds, preprocessing the collected pictures to expand the data set and enhance the robustness of the model, using the YOLO V5 model to extract the features of crops and weeds from the preprocessed pictures, and respectively establishing databases for crop features and weed features according to the extracted features to form the seedling and weed recognition system. Then input the image of the weeding area into the seedling and weed recognition system for comparison to identify the weeds, and further determine the positions of the weeds; S3. The controller respectively controls each of the second drive motors to rotate forward or backward, so that the first link of each link assembly moves in different directions, driving the lower platform to lift and move horizontally, so that the nozzle is aligned with the weeds.

10. The control method of a parallel mechanism precision spraying robot according to claim 9, characterized in that: The parallel mechanism precision spraying robot further includes a lidar disposed on the water tank. The controller is connected to the lidar, and the control method further includes: The controller acquires map data, and the map data includes aerial image data of the weeding area, the image of the weeding area, and radar data; The controller optimizes the map data by using the SLAM algorithm, and divides the map data into four layers: the plot information layer, the obstacle layer, the weeding operation information layer, and the dynamic perception layer. The plot information layer includes plot boundaries, entrances and exits, and tractor roads. The obstacle layer includes inherent obstacles. The operation information layer includes map information for the weeding machine to carry out weeding. The dynamic perception layer is the surrounding environment information obtained by fusing the image of the weeding area and radar data; The controller uses the A* algorithm to find the shortest path from the current position of the parallel mechanism precision spraying robot to the target position in the weeding area in the optimized map data; The controller controls the mobile cart to move along the shortest path.

Images