Double-helix driving and fluid disturbance type paddy field weeding robot and automatic cruise weeding method

Abstract

The invention discloses a double-spiral driving and fluid disturbance type paddy field weeding robot and an automatic cruise weeding method. The robot comprises a spiral driving wheel mechanism, a transmission mechanism, a supporting rack, a sealed control cabin and a control system. The spiral driving wheel mechanism comprises two spiral driving wheels which are arranged in parallel, and the spiral driving wheels are symmetrically mounted at the bottom of the supporting rack along the central axis; the transmission mechanism is installed on the two spiral driving wheels and used for achieving power transmission between the driving motor and the main shafts of the spiral driving wheels. The supporting rack is used for providing overall bearing and structural supporting for the spiral wheel driving wheel mechanism and the sealing control cabin. The control system is used for controlling the motor to drive the spiral wheel driving mechanism to rotate. Axial propulsive force and a radial disturbance flow field are generated in a muddy water environment through the double-spiral driving wheel, the synergistic effect of mud fluid power disturbance and weed root system damage is formed, and therefore efficient physical weeding is achieved under the condition that chemical agents are not needed.

Description

Technical Field

[0001] This invention belongs to the field of intelligent agricultural machinery technology, specifically relating to a double-helix drive and fluid disturbance type paddy field weeding robot and an automatic cruise weeding method. Background Technology

[0002] Currently, weeding in paddy fields relies heavily on manual labor or chemical agents. Manual weeding is labor-intensive, costly, and lacks timeliness; while chemical herbicides are highly efficient, they pollute the environment and water quality, potentially impacting the quality of the rice growing environment. Existing mechanized weeding equipment, although efficient, often suffers from reduced reliability in soft, muddy paddy fields due to the drive mechanism easily getting stuck in the mud. Furthermore, the lack of efficient planning algorithms makes it difficult to achieve full coverage and adaptive path adjustment. In addition, existing systems often have scattered sensors, drives, and path planning components, lacking integrated design, resulting in insufficient system performance and reliability. Therefore, there is a need for an automated cruising weeding robot suitable for paddy field environments, capable of maintaining good buoyancy and traction in muddy conditions to achieve mechanical and physical weeding; simultaneously, it should combine efficient path planning and GPS navigation to achieve full-coverage, high-efficiency autonomous cruising operations, and possess an integrated sensing, planning, and control workflow. Summary of the Invention

[0003] The main objective of this invention is to overcome the shortcomings and deficiencies of the prior art and to propose a double-helix driven and fluid disturbance type paddy field weeding robot and an automatic cruise weeding method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A double-helix driven and fluid disturbance type paddy field weeding robot includes a helix drive wheel mechanism, a transmission mechanism, a support frame, a sealed control chamber, and a control system;

[0006] The helical drive wheel mechanism includes two helical drive wheels arranged side by side, which are symmetrically mounted on the bottom of the support frame along the central axis;

[0007] The transmission mechanism, mounted on two spiral drive wheels, is used to realize the power transmission between the drive motor and the main shaft of the spiral drive wheel, and to drive the spiral drive wheel to rotate relative to the support frame.

[0008] The support frame provides overall load-bearing and structural support for the propeller drive wheel mechanism and the sealed control compartment;

[0009] The sealed control compartment is fixed to the top of the supporting frame;

[0010] The control system, used to control the rotation of the transmission mechanism driving the screw wheel drive mechanism, is located inside the sealed control chamber.

[0011] The present invention also includes an automated cruise weeding method based on the provided paddy field weeding robot, comprising the following steps:

[0012] S1. Obtain field boundary information and divide the work area into a central work area and a contour area;

[0013] S2. Shrink the boundary polygon of the contour area to obtain the shrunken feasible working boundary.

[0014] S3. Generate several equally spaced parallel strips in a predetermined direction within the inwardly narrowed feasible working boundary area and the central working area.

[0015] S4. Sort the generated parallel strips according to the Warnsdorff rule to determine the order in which the robot will patrol the strips.

[0016] S5. Use Dubins curves and Reeds-Shepp curves to splice the paths of adjacent strips to form a continuous and smooth robot motion trajectory;

[0017] S6. The above steps generate an adaptive cruise path covering the entire work area. The robot automatically travels along the path using the GPS navigation module. The double helix drive wheel stirs up the surface soil during its forward movement, changes the turbidity of the water layer, destroys the roots of weeds, and prevents weeds from photosynthesizing, thus achieving physical weeding.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] 1. The invention features an integrated design, with a double-helix drive structure and reinforced frame that enhance rigidity and durability. The double-helix drive wheels provide excellent traction and a large contact area, significantly improving the robot's ability to avoid sinking and its adaptability in soft muddy fields. It employs mechanical disturbance to achieve physical weeding, utilizing the double-helix drive wheels to achieve dual physical weeding through "soil and water disturbance-light suppression" and "root stripping," eliminating the need for chemical agents, making it environmentally friendly, and contributing to soil improvement.

[0020] 2. The method of this invention fully considers the shape of the work area and the kinematics of the robot, and adopts techniques such as center area / contour area division, polygon shrinkage and parallel strip generation to achieve a full-coverage and highly efficient work path; Warnsdorff rules and Dubins / Reeds-Shepp splicing ensure that the path is coherent and smooth, and highly adaptable to environmental changes.

[0021] 3. Integrated system operation process: It integrates cameras and GPS sensing systems for environmental perception, and combines real-time path planning and motion control to form a closed-loop integrated operation process of "perception, path generation, motion control, and execution", which improves the level of automation and intelligence. Attached Figure Description

[0022] Figure 1 This is a three-dimensional view of the paddy field weeding robot of the present invention.

[0023] Figure 2 This is a front view of the paddy field weeding robot of the present invention.

[0024] Figure 3 This is a schematic diagram of the helical drive wheel mechanism in this invention.

[0025] Figure 4 This is a schematic diagram of the support frame in this invention.

[0026] Figure 5 This is a schematic diagram of the transmission mechanism in this invention.

[0027] Figure 6 This is a schematic diagram of the sealed control chamber in this invention.

[0028] Figure 7 This is a flowchart of the automatic cruise weeding method in the embodiment.

[0029] Figure 8 This is a schematic diagram of the complete cruise route.

[0030] Explanation of reference numerals: 1-Sealed control chamber; 2-Support frame; 3-Transmission mechanism; 4-Camera gimbal; 5-Screw drive wheel mechanism; 11-Sealing cover; 12-Sealing ring; 13-Waterproof joint; 14-Bus; 21-Front bearing support; 22-U-shaped frame; 23-Truss; 24-Rear bearing support; 31-Locking end cover; 32-Driven shaft; 33-Drive shaft; 34-Drive motor; 51-Left screw drive wheel; 52-Left rotating screw blade; 53-Right screw drive wheel; 54-Right rotating screw blade. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0032] Examples; such as Figure 1 and Figure 2 As shown, a double-helix driven and fluid disturbance type paddy field weeding robot includes a helical drive wheel mechanism 5, a transmission mechanism 3, a support frame 2, a sealed control chamber 1, and a control system.

[0033] The helical drive wheel mechanism includes two helical drive wheels arranged side by side, which are symmetrically mounted on the bottom of the support frame along the central axis;

[0034] The transmission mechanism, mounted on two spiral drive wheels, is used to realize the power transmission between the drive motor and the main shaft of the spiral drive wheel, and to drive the spiral drive wheel to rotate relative to the support frame.

[0035] The support frame provides overall load-bearing and structural support for the propeller drive wheel mechanism and the sealed control compartment;

[0036] A sealed control compartment, fixed to the top of the support frame, is used to securely encapsulate the robot's control system and power supply.

[0037] The control system, which controls the transmission mechanism to drive the screw wheel drive mechanism to rotate, is located in a sealed control cabin and can be switched between manual remote control and autonomous navigation.

[0038] In this embodiment, as Figure 3 As shown, the spiral drive wheel mechanism includes a left spiral drive wheel 51 and a right spiral drive wheel 53. The two spiral drive wheels are arranged side by side on the support frame, with their central axes parallel to each other and maintaining a set distance to adapt to paddy field operation paths of different widths.

[0039] Each helical drive wheel is equipped with continuous helical blades. The left helical drive wheel has left-rotating helical blades 52, which are arranged counterclockwise along the axial direction. The right helical drive wheel has right-rotating helical blades 54, which are arranged clockwise along the axial direction. During operation, the rotating helical blades efficiently push the soil from the central area to the rear and sides, loosening, disturbing, and turning the soil, thus achieving multiple agricultural machinery functions such as weeding, breaking up soil clumps, and aeration.

[0040] In this embodiment, as Figure 4 As shown, the support frame specifically includes a U-shaped frame 22, a truss 23, a front bearing support 21, and a rear bearing support 24;

[0041] There are two U-shaped frames, arranged symmetrically along the center; each U-shaped frame is equipped with a front bearing support and a rear bearing support at its front and rear ends, respectively.

[0042] There are four trusses. The two U-shaped frames are laterally connected and reinforced by four trusses symmetrically distributed on the left and right sides to improve the overall strength of the frame and enhance the stability of the robot in the soft mud environment.

[0043] In this embodiment, as Figure 5 As shown, the transmission mechanism specifically includes a driven shaft 32, a drive shaft 33, a rolling bearing, a locking end cover 31, and a drive motor 34;

[0044] There are two driven shafts and two driving shafts. The driven shaft is located at the front end of the helical drive wheel, and the driving shaft is located at the rear end of the helical drive wheel. Both are locked with bolts to ensure coaxiality with the main shaft of the helical drive wheel, reducing vibration and eccentric load during operation. There are four rolling bearings, one for each of the driven shaft and the driving shaft. The rolling bearings are fixed in the front and rear bearing supports by retaining rings to provide radial and axial support for the shaft.

[0045] There are two drive motors, which are fixed to two rear bearing supports by bolts; the output shaft of the drive motor is equipped with a key block structure, which cooperates with the keyways on the two drive shafts to realize power transmission;

[0046] Two locking end caps are used to fix the screw wheel drive mechanism axially within the front and rear bearing supports using bolts.

[0047] In this embodiment, as Figure 6 As shown, the sealed control chamber specifically includes a chamber body 14, a sealing ring 12, a sealing cover 11, and a waterproof connector 13;

[0048] The cabin is fixed to the top of the support frame, with a sealing cover on top and a sealing ring between the cabin and the sealing cover, forming a ring-shaped sealing interface through compression. Two waterproof joints are located on the side panels of the cabin, enabling external connection of the cable lines and preventing moisture infiltration. The sealed control cabin possesses excellent waterproof and dustproof performance, effectively preventing rainwater, mud, and other external impurities from entering the control cabin, ensuring reliable operation of electronic components in harsh environments such as waterlogged, humid, and muddy conditions.

[0049] In this embodiment, the control system is housed within the sealed control cabin and is used to precisely control the rotation of the motor-driven helical wheel drive mechanism. The control system employs an STM32F407VET6 microcontroller as the main control unit and is remotely operated via wireless remote control. The communication protocol used is the SBUS digital communication protocol, which offers advantages such as high transmission speed and strong signal anti-interference capabilities. Operation commands can be sent to the main control microcontroller in real time via a wireless remote control device. The microcontroller controls the start, stop, and direction of each drive motor based on the received signals, enabling remote autonomous navigation or manual control, path control, and task execution for the robot. This control system, combining differential speed algorithms and environmentally adaptive control strategies, possesses excellent scalability and potential for intelligent applications.

[0050] In this embodiment, a GPS navigation module and a camera gimbal 4 are also included to achieve high-precision positioning and navigation as well as remote environmental perception. The GPS navigation module is connected to the control system via CAN communication.

[0051] The GPS navigation module includes an RTK antenna and a navigation controller. The RTK antenna employs real-time dynamic differential positioning technology and, connected to the navigation controller, enables real-time acquisition of centimeter-level high-precision positioning data. The navigation controller incorporates a high-performance navigation computing chip, providing functions such as path import, operation status display, speed adjustment and parameter calibration, and data export. Control commands are transmitted in real-time from the navigation controller to the main control system and drive system via the CAN bus communication protocol, ensuring the real-time performance and reliability of the path tracking control process. The navigation controller supports multiple path planning modes, including straight lines, curves, and segmented trajectories, and possesses attitude control capabilities, dynamically adjusting the machine's attitude according to terrain changes to achieve high-precision path tracking and attitude adjustment.

[0052] The camera gimbal is mounted on the top surface of the sealed cover and is integrated with the robot control system. It is equipped with a 4G wireless communication module to transmit image data back to the remote monitoring terminal or cloud platform in real time, enabling remote operation supervision and environmental perception.

[0053] In this embodiment, a solar charging panel, a battery, and a power voltage regulator module are also included; the battery and the power voltage regulator module are disposed inside the sealed control cabin, and the solar charging panel is disposed above the top surface of the sealed cover.

[0054] When the paddy field weeding robot of this invention is operating, the left and right helical drive wheels are driven by independent motors, and the helical blades are arranged in opposite directions and move at angular velocity. Rotate, the whole machine moves forward at a forward speed Uniform speed propulsion. During rotation and propulsion, the helical blades continuously shear, compress, and scatter the surface soil, suspending mud particles to form a highly turbid water layer. This significantly weakens the light intensity entering the water and inhibits the photosynthesis of weed seedlings. This process continues upstream and to the sides of the robot's path. The opposing helical blades create a symmetrical shear flow field and secondary vortex in the central region of the robot. The mud-root complex experiences alternating tangential "push-pull" and normal "compression-pull" loads around the blade periphery. When the effective shear stress and shear work applied by the blades exceed the shear strength and decoupling energy threshold of the soil-root interface, root stripping, breakage, or burial occurs, thus achieving physical weed control. Simultaneously, the helical structure increases the contact area and outputs stable axial propulsion force, improving traction and passage capacity in soft mud environments while achieving weed control, ensuring operational stability and continuity.

[0055] In this embodiment, the helical drive wheel performs disturbance operations in a mud-water two-phase medium, and its weeding process is accompanied by the coupling of longitudinal and tangential shear displacements. Because paddy field mud is a highly viscous and weakly plastic material, the helical drive wheel will experience slippage during propulsion, with the actual forward distance being less than the theoretical displacement distance, resulting in a slip ratio *i* and a slip velocity. .

[0056] This slip effect directly affects the shear deformation and stress distribution of mud particles and is a key factor in weeding root system damage and energy consumption balance.

[0057] The spiral drive wheel advances horizontally at a linear velocity v and rotates at an angular velocity ω. In the ideal state without slip, the theoretical traveling speed of the spiral drive wheel is:

[0058]

[0059] where P is the pitch; due to the viscous and blocking effects of the mud-root layer, the actual speed v of the spiral wheel is less than , and the slip rate is defined as:

[0060]

[0061] Thus, the slip speed of the mud relative to the spiral wheel can be obtained:

[0062]

[0063] When the mud particles are pushed at the leading edge of the blade, relative slip occurs along the spiral axis direction. Let the travel distance of the spiral wheel in the forward direction be L, then the longitudinal shear displacement can be obtained by integrating the slip speed:

[0064]

[0065] From the passing time t = L / v of the spiral wheel in the mud layer, it can be obtained:

[0066]

[0067] where i is the slip rate (0 < i < 1); P is the pitch; ω is the angular velocity; L is the contact length of the blade with the mud layer; v is the propulsion speed. The longitudinal shear displacement characterizes the sliding deformation ability of the mud medium in the forward direction and is the dominant factor in root decoupling damage.

[0068] During the rotation of the blade, in addition to the longitudinal slip, the mud particles also generate tangential shear displacement along the circumferential direction of the blade. This displacement comes from the tangential slip velocity component of the blade, and the tangential slip displacement can be expressed in integral form as:

[0069]

[0070] where , is the equivalent shear radius, taking the average value of the blade radius and its embedded depth h, Then we have:

[0071]

[0072] This formula shows that when the slip ratio i is large (i.e., the mud resistance is large), the longitudinal displacement increases while the tangential displacement decreases; when i is small, the tangential shear is significantly enhanced, which easily leads to the formation of local mud churn zones and root disturbance layers.

[0073] The combined longitudinal and tangential shear forces result in the total shear displacement at the mud-root interface:

[0074]

[0075] Paddy field mud is a typical plastic-rheological mixture, and its shear strength is... The dynamic shear stress distribution varies with shear rate and depth. Based on the Mohr–Coulomb criterion and combined with the rheological properties of mud, the expression for the dynamic shear stress distribution under the action of the propeller blades can be obtained as follows:

[0076]

[0077] in, The apparent cohesion of the mud layer; The equivalent normal pressure distribution of the blade on the interface at the circumferential angle (varying with blade angle of attack and penetration depth); The internal friction angle of the mud-water mixture; This is the shear stress attenuation coefficient with depth (related to density and moisture content). ).

[0078] The shear strength of the mud-root bond layer is written as:

[0079]

[0080] when At this time, local plastic slip and structural failure occur, entering the "shear zone" state, which provides the necessary conditions for root instability.

[0081] When the helical drive wheel rotates, the pitch P of the helical blades and the forward speed v together determine the propulsion angle. , is represented as:

[0082]

[0083] The leading edge of the blade exerts a combined effect of normal thrust and tangential shear force on the mud particles, creating a localized zone of strong disturbance. The shear stress at this point is decomposed as follows:

[0084]

[0085]

[0086] in, Longitudinal shear stress dominates root decoupling; Tangential shear stress dominates mud disturbance. In the leading edge region of the blade, Larger areas cause root separation from the soil layer; at the leaf's trailing edge, The dominant force forms a vortex zone that pulls the fractured root system into the mud, achieving secondary disturbance and burial.

[0087] The double helix drive wheels rotate in opposite directions At this time, a symmetrical vortex flow field is formed, causing superimposed disturbances in the mud in the central region at the bottom of the robot. The concentration C of suspended mud particles and the turbidity T in this disturbance flow field satisfy the following relationship:

[0088]

[0089] Where H is the thickness of the disturbance layer and β is the settling attenuation coefficient. By adjusting the rotational speed ω of the auger and the operating speed v, the disturbance intensity can be adaptively adjusted under different mud layer conditions, ensuring sufficient root destruction, uniform mud layer disturbance, and optimal operational efficiency during weeding, thereby guaranteeing the stability and economy of the overall operation.

[0090] The shear power density generated by the blade per unit time satisfy:

[0091]

[0092] When the conditions for root decoupling and destruction are met, the weed roots are pulled out, broken, or buried, achieving chemical-free physical weed control. For effective sliding speed, The root decoupling threshold power density.

[0093] The entire weeding process can be divided into the following stages:

[0094] Entry Stage: As the auger drive wheel advances along the working direction, the auger blades gradually embed themselves into the upper layer of mud. The leading edge of the blades applies normal pressure to the mud layer, while simultaneously generating significant tangential shear force during rotation, increasing stress concentration at the mud-root interface. During this stage, the cemented structure between the root system and the mud layer is subjected to periodic pushing and shearing, leading to microcracks and plastic slippage at the local cemented interface, creating conditions for subsequent root damage.

[0095] Disturbance Stage: As the helical drive wheel continues to rotate, the helical blades generate significant fluid disturbance and particle agitation effects in the water-mud two-phase medium. At this time, a high shear rate zone and a local negative pressure zone appear in the mud flow field, forcing mud particles to undergo relative slippage and rotational motion. Under this high shear environment, the root system undergoes plastic deformation and tensile failure, with some roots being cut off or pulled out of the mud layer, achieving the main weeding effect.

[0096] Backflow stage: A low-pressure backflow zone is generated at the trailing edge of the helical blades due to the difference in the rotating flow field. The disturbed mud forms a circumferential vortex at the blade tail. These backflow vortices mix the broken roots with mud particles, causing some roots to float and drift or be reburied in the mud layer, thus blocking their regeneration conditions. The flow characteristics in this stage effectively promote the redistribution of the mud layer and enhance the mud's ability to bury and fix broken roots.

[0097] Stable Phase: When the left and right helical drive wheels rotate in opposite directions, a symmetrical turbulent equilibrium zone is formed at the bottom of the robot. At this time, the mud disturbance tends to be uniform, the shear gradient inside the flow field stabilizes, and the system enters a steady-state operation. During this phase, the mud maintains moderate disturbance, creating a slightly turbid zone on the surface of the paddy field, reducing the depth of light transmission, thereby inhibiting the germination of weed seeds and the secondary growth of residual roots. Simultaneously, the system maintains the rotational speed balance of the helical wheels through real-time feedback control, ensuring a smooth and continuous operation and achieving a balance between efficient weed control and low energy consumption.

[0098] Compared with simple rolling or cutting weeding, this invention achieves dual destruction of the physiological processes (photosynthesis) and physical structure (root fixation) of weeds through the combined action of fluid dynamics and soil mechanics, resulting in more thorough and lasting weed control; at the same time, the spiral structure increases the contact area with the soil, providing good traction and effectively preventing weeds from getting stuck in the mud.

[0099] In another embodiment, an automatic cruise weeding method for a paddy field weeding robot based on the above embodiments is also provided, including the following steps:

[0100] S1. Obtain field boundary information and divide the work area into a central work area and a contour area;

[0101] S2. Shrink the boundary polygon of the contour area to obtain the shrunken feasible working boundary.

[0102] S3. Generate several equally spaced parallel strips in a predetermined direction within the inwardly narrowed feasible working boundary area and the central working area.

[0103] S4. Sort the generated parallel strips according to the Warnsdorff rule to determine the order in which the robot will patrol the strips.

[0104] S5. Use Dubins curves and Reeds-Shepp curves to splice the paths of adjacent strips to form a continuous and smooth robot motion trajectory;

[0105] S6. The above steps generate an adaptive cruise path covering the entire work area. The robot automatically travels along the path using the GPS navigation module. The double helix drive wheel stirs up the surface soil during its forward movement, changes the turbidity of the water layer, destroys the roots of weeds, and prevents weeds from photosynthesizing, thus achieving physical weeding.

[0106] In step S1, the robot determines its current location using GPS positioning and work area boundary information, and automatically divides the central work area and outline area according to the shape of the field to ensure the integrity and efficiency of path planning.

[0107] In step S2, the indentation distance is determined based on the robot size and safety clearance to ensure that the robot does not collide with the boundary when working in the contour area;

[0108] In step S3, the strip direction is preset or dynamically adjusted according to the length and width ratio of the field to optimize the length of the coverage path;

[0109] In step S5, Dubins curves are used to connect straight road segments in the same direction to maintain smooth forward steering, and Reeds-Shepp curves are used to realize reverse U-turns to meet the terminal reversing requirements; the spliced ​​path simultaneously meets the requirements of minimum turning radius constraints and driving smoothness.

[0110] In step S6, during the operation, the robot forms a closed-loop control system based on RTK-GNSS positioning data and differential control algorithm, and adjusts the speed difference between the left and right helical drive wheels in real time to correct the deviation, so as to realize path adaptive tracking and continuous operation, and ensure the continuity and safety of the operation process.

[0111] In actual implementation, such as Figure 7 As shown, the method includes the following steps:

[0112] Work area division (corresponding to steps S1 and S2): The robot acquires the geographic coordinates of the field boundary via the RTK antenna, establishes a map of the work area, and then performs path planning. Within the work area, based on shape and area, it is divided into a central work area and a contour work area. The central work area is a relatively regular internal region, while the contour work area has complex edges. For the contour work area, a polygon shrinkage technique is used to gradually shrink its boundary, obtaining a feasible working boundary after shrinkage. This ensures the robot has sufficient operating space and avoids collisions or loss of control due to proximity to the boundary.

[0113] Operation path determination (step S3): Based on the plot boundaries and crop row layout, the area is divided into several parallel operation zones, each with a width of 0.3m (matching the robot's weeding operation width) to ensure that the robot can cover the crop rows each time it makes a round trip. In addition, obstacle areas are identified, and obstacle avoidance routes are planned.

[0114] Path sequence determination (step S4): According to the Warnsdorff rule, starting from the initial work zone (e.g., the zone closest to the robot), when selecting the next uncovered work zone, priority is given to those work zones with the fewest possible future connecting paths. This rule is similar to Warnsdorff's greedy strategy, used to reduce the risk of subsequent blockages and optimize path coverage.

[0115] Turning path calculation (step S5): For the connection between every two consecutive work zones, a smooth curved path is generated by the Dubins and Reeds-Shepp algorithms. The Dubins path algorithm takes into account the physical limitation of the robot's minimum turning radius of 0.6m and outputs an arc turning segment connecting two straight paths, while the Reeds-Shepp path allows reversing operations and is used in special scenarios such as contour work areas that require flexible turning, so as to balance execution flexibility and work standardization, and ensure that the robot turns smoothly and feasiblely.

[0116] Finally (step S6), the straight and curved segments are sequentially joined to form a complete cruising path, such as... Figure 8 As shown, the precise coordinate trajectory sequence that the robot should follow is obtained and loaded into the navigation controller module.

[0117] The above steps generate a complete cruising path covering the entire field, ensuring the path satisfies robot kinematic constraints and is as short and efficient as possible. The robot's GPS navigation module and control system perform motion control based on the generated path and real-time GPS position. First, the control system divides the path into a series of target points, and the robot proceeds to these points in a predetermined order. During travel, the system uses high-precision RTK-GNSS positioning to acquire the robot's spatial coordinates and attitude information in the field in real time. The control system compares the real-time measured position information with the pre-planned work path, calculating key control quantities such as lateral deviation, heading deviation, and attitude angle error. Based on this error information, the system uses a closed-loop control algorithm (PID) for dynamic feedback adjustment, correcting the speed difference between the left and right helical drive wheels or the deflection angle of the front steering mechanism in real time. Specifically, the proportional (P) terminator is used for rapid response to path deviations, the integral (I) terminator is used to eliminate persistent accumulated errors, and the derivative (D) terminator is used to suppress dynamic oscillations caused by sudden changes or slippage during path tracking. Through the coordinated control of these three components, the robot can maintain its stability and path accuracy even in complex paddy field terrain and low-adhesion mud environments. Ultimately, the robot is able to achieve centimeter-level path tracking accuracy based on RTK positioning data, ensuring smooth progress along the planned route.

[0118] This invention achieves the organic integration of structure, algorithm, and control, and has the following beneficial effects: the robot moves stably and has strong traction, easily overcoming complex field terrain; the path planning is reasonable, the work efficiency is high, the coverage during operation is complete, and repeated travel is reduced; high-precision RTK positioning and closed-loop control ensure the accuracy of navigation; the use of solar power extends the working time, saving energy and protecting the environment; the whole system can operate automatically without human intervention, significantly reducing the need for manual intervention and improving the level of intelligence in agricultural production.

[0119] It should also be noted that, in this specification, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0120] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A double-helix driven and fluid disturbance type paddy field weeding robot, characterized in that, It includes a screw drive wheel mechanism, a transmission mechanism, a support frame, a sealed control chamber, and a control system; The helical drive wheel mechanism includes two helical drive wheels arranged side by side, which are symmetrically mounted on the bottom of the support frame along the central axis; The transmission mechanism, mounted on two spiral drive wheels, is used to realize the power transmission between the drive motor and the main shaft of the spiral drive wheel, and to drive the spiral drive wheel to rotate relative to the support frame. The support frame provides overall load-bearing and structural support for the propeller drive wheel mechanism and the sealed control compartment; The sealed control compartment is fixed to the top of the supporting frame; The control system, used to control the rotation of the transmission mechanism driving the screw wheel drive mechanism, is located inside the sealed control chamber.

2. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 1, characterized in that, The screw drive wheel mechanism includes a left screw drive wheel and a right screw drive wheel. The two screw drive wheels are arranged side by side on the support frame, with their central axes parallel to each other and maintaining a set distance to adapt to paddy field operation paths of different widths. All the spiral drive wheels are equipped with continuous spiral blades. The left spiral drive wheel has left-rotating spiral blades, which are arranged counterclockwise along the axial direction. The right spiral drive wheel has right-rotating spiral blades, which are arranged clockwise along the axial direction.

3. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 1, characterized in that, The support frame specifically includes a U-shaped frame, a truss, a front bearing support, and a rear bearing support. There are two U-shaped frames, arranged symmetrically along the center; each U-shaped frame is equipped with a front bearing support and a rear bearing support at its front and rear ends, respectively. There are four trusses. The two U-shaped frames are laterally connected and reinforced by four trusses symmetrically distributed on the left and right sides to improve the overall strength of the frame and enhance the stability of the robot in the soft mud environment.

4. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 3, characterized in that, The transmission mechanism specifically includes a driven shaft, a drive shaft, rolling bearings, a locking end cover, and a drive motor; There are two driven shafts and two driving shafts. The driven shaft is located at the front end of the helical drive wheel, and the driving shaft is located at the rear end of the helical drive wheel. Both are locked with bolts to ensure coaxiality with the main shaft of the helical drive wheel. There are four rolling bearings, one for each of the driven shafts and the driving shaft. The rolling bearings are fixed in the front and rear bearing supports by retaining rings. There are two drive motors, which are fixed to two rear bearing supports by bolts; the output shaft of the drive motor is equipped with a key block structure, which cooperates with the keyways on the two drive shafts to realize power transmission; Two locking end caps are used to fix the screw wheel drive mechanism axially within the front and rear bearing supports using bolts.

5. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 1, characterized in that, The sealed control compartment specifically includes the compartment body, sealing ring, sealing cover, and waterproof joint; The cabin is fixed on the top of the support frame, the sealing cover is located on the top of the cabin, the sealing ring is located between the cabin and the sealing cover, and there are two waterproof joints, which are respectively located on the side plates of the cabin.

6. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 5, characterized in that, It also includes a GPS navigation module and a camera gimbal, with the GPS navigation module connected to the control system via CAN communication; The camera gimbal is mounted on the top surface of the sealed cover and is integrated with the robot control system. It is equipped with a 4G wireless communication module to transmit image data back to the remote monitoring terminal or cloud platform in real time, enabling remote operation supervision and environmental perception. It also includes a solar charging panel, a battery, and a power voltage regulator module; the battery and power voltage regulator module are located inside the sealed control cabin, and the solar charging panel is located above the top surface of the sealed cover.

7. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 1, characterized in that, The left and right helical blades of the double-helix drive wheel rotate in opposite directions; The double-helix drive wheel rotates at an angular velocity ω and moves horizontally at a linear velocity ν during operation, forming a composite disturbance field with both longitudinal and tangential shear displacements. The shear displacement satisfies the following equation: in, Longitudinal shear displacement represents the relative slippage of the mud medium along the forward direction; This represents the tangential shear displacement, indicating the amount of slippage of mud particles around the helical axis. The equivalent shear radius; when the helical blades of the helical drive wheel rotate in the cement two-phase medium, the propulsion angle is used as the effective shear radius. The coupling effect of longitudinal thrust and tangential disturbance force is generated, forming a periodic shear disturbance field at the mud-root interface, thereby achieving physical destruction and decoupling of the weed root system.

8. The double-helix driven and fluid disturbance type paddy field weeding robot according to claim 7, characterized in that, The dynamic shear stress distribution in the mud medium satisfies: in, For the apparent cohesion of the mud, This represents the normal stress at the blade angular position. It is the internal friction angle. The shear depth attenuation coefficient; when At this time, the root system undergoes plastic slippage or breakage; This represents the shear strength of the root-bonded layer. The mud shear stress during the rotation of the screw wheel is decomposed into: in, Longitudinal shear stress promotes separation of the root system from the mud layer interface; Tangential shear stress drives the mud to tumble and form a backflow vortex zone, promoting secondary disturbance and burial of the root system; The double helix drives the wheels to rotate in opposite directions, that is... At this time, a symmetrical vortex flow field is formed, causing superimposed disturbances in the mud in the central region at the bottom of the robot. The concentration C of suspended mud particles and the turbidity T in this disturbance flow field satisfy the following relationship: Where H is the thickness of the disturbance layer and β is the settling attenuation coefficient; by adjusting the rotation speed ω of the auger and the working speed v, the disturbance intensity can be adaptively adjusted under different mud layer conditions, so that the root system is fully destroyed, the mud layer is disturbed evenly and the working efficiency is optimal during the weeding process, thereby ensuring the stability and economy of the overall operation. The shear power density generated by the blade per unit time satisfy: Then the mud-root interface reaches the fracture condition; where For effective sliding speed, The root decoupling threshold power density; When the double helix wheel is working, the intensity of local disturbance is adjusted through differential speed control. The control system adjusts the speed difference between the left and right wheels. To maintain shear strength This ensures the continuity and stability of weed control.

9. An automatic cruise weeding method based on the paddy field weeding robot according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Obtain field boundary information and divide the work area into a central work area and a contour area; S2. Shrink the boundary polygon of the contour area to obtain the shrunken feasible working boundary. S3. Generate several equally spaced parallel strips in a predetermined direction within the inwardly narrowed feasible working boundary area and the central working area. S4. Sort the generated parallel strips according to the Warnsdorff rule to determine the order in which the robot will patrol the strips. S5. Use Dubins curves and Reeds-Shepp curves to splice the paths of adjacent strips to form a continuous and smooth robot motion trajectory; S6. The above steps generate an adaptive cruise path covering the entire work area. The robot automatically travels along the path using the GPS navigation module. The double helix drive wheel stirs up the surface soil during its forward movement, changes the turbidity of the water layer, destroys the roots of weeds, and prevents weeds from photosynthesizing, thus achieving physical weeding.

10. The automatic cruise weeding method according to claim 9, characterized in that, In step S1, the robot determines its current location using GPS positioning and work area boundary information, and automatically divides the central work area and outline area according to the shape of the field to ensure the integrity and efficiency of path planning. In step S2, the indentation distance is determined based on the robot size and safety clearance to ensure that the robot does not collide with the boundary when working in the contour area; In step S3, the strip direction is preset or dynamically adjusted according to the length and width ratio of the field to optimize the length of the coverage path; In step S5, Dubins curves are used to connect straight road segments in the same direction to maintain smooth forward steering, and Reeds-Shepp curves are used to realize reverse U-turns to meet the terminal reversing requirements; the spliced ​​path simultaneously meets the requirements of minimum turning radius constraints and driving smoothness. In step S6, during the operation, the robot forms a closed-loop control system based on RTK-GNSS positioning data and differential control algorithm, and adjusts the speed difference between the left and right helical drive wheels in real time to correct the deviation, so as to realize path adaptive tracking and continuous operation, and ensure the continuity and safety of the operation process.

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