Paddy field plant protection machine with double-stage suspension tracked chassis

Abstract

The utility model relates to a paddy field plant protection machine with double-stage suspension tracked chassis, belongs to the field of agricultural machinery, the paddy field plant protection machine includes chassis device, two axle mechanical arm spraying device, DC drive motor, the chassis device includes built-in suspension device and external suspension device, and both can realize the buffer of small amplitude terrain height difference and large amplitude terrain height difference, the two axle mechanical arm spraying device covers the plant type change of crops whole growth period depending on horizontal rotation joint and pitch swing arm joint, realizes target site precision pesticide application, the DC drive motor provides power for tracked walking, realizes steering through setting up different rotating speed on both sides, guarantees muddy road surface traction and small field block steering flexibility.

Description

Technical Field

[0001] This utility model belongs to the field of agricultural machinery, and is a specially designed paddy field plant protection machine with a dual-stage suspension tracked chassis. Background Technology

[0002] In agricultural production, plant protection machines are specialized agricultural machinery used for pest and disease control, nutrient regulation, and growth assistance throughout the entire growth cycle of crops. By replacing traditional manual spraying with mechanized operations, they can significantly improve operational efficiency, reduce pesticide waste, and lower the intensity of manual labor. They are key equipment for ensuring crop yield and quality in the process of agricultural modernization. Their core functions include the precise spraying of pesticides, nutrient solutions, and growth regulators according to the crop's growth needs. Their operating scenarios cover various farming environments such as dry land, paddy fields, orchards, and tea gardens. Among these, plant protection machines for paddy fields, which need to adapt to the special muddy, watery, and ridge-filled environment, have become one of the technical challenges in the field of plant protection machinery.

[0003] Plant protection operations are a crucial step in ensuring the healthy growth of crops, directly impacting their health and final yield. For paddy crops like rice, 5-8 plant protection operations are required during the nearly four-month growth cycle from tillering to maturity. Each operation must address different types of pests and diseases and the characteristics of the crop plant. For example, during the tillering stage, the focus is on controlling leaf blast, ensuring even coverage of young leaves with pesticide; during the heading stage, targeted control of rice false smut requires precise spraying of pesticide onto the panicles; and during maturity, attention must be paid to sheath blight, necessitating targeted application of pesticides to the basal stems. These operational requirements not only demand stable driving capabilities from the plant protection machinery but also guarantee the accuracy and uniformity of pesticide application.

[0004] However, the unique characteristics of paddy field environments present multiple challenges to plant protection machinery operations: First, paddy field soil is saturated with water for extended periods, making it heavy and with low bearing capacity. Traditional wheeled plant protection machinery, due to its high ground pressure, is prone to sinking into the mud, resulting in a high rate of vehicle entrapment. This not only disrupts the operation process but also crushes crop roots and damages the topsoil. Second, paddy field plots are often separated by field ridges, and the surface has natural undulations, such as shallow ditches and localized uplifts. Traditional tracked plant protection machinery, with its simple suspension system design, is prone to severe vibrations when crossing field ridges or traversing undulating terrain, leading to nozzle swaying, poor pesticide atomization, and frequent missed spraying. Third, rice plant shapes change dynamically with the growth stage. Existing plant protection machinery nozzles are mostly fixed-angle or single-degree-of-freedom adjustable, making it difficult to adapt to the application needs of different growth stages. For example, during the heading stage, the upper leaves may obstruct the pesticide coverage of the rice ears, resulting in reduced pest and disease control effectiveness.

[0005] While existing mechanization solutions have undergone some improvements, they have not adequately addressed the vibration issues when crossing obstacles and lack coordinated design with vehicle stability. Currently, high-quality paddy field plant protection operations still rely on manual assistance for correction, which increases production costs and exacerbates the risk of farmland ecological pollution. There is an urgent need to develop paddy field plant protection machinery and equipment that can achieve stable operation in complex terrain and precise application of pesticides throughout the entire growth period.

[0006] Currently, my country has researched and invented some equipment for automated agricultural spraying and plant protection machines. For example, patent CN206658912U proposes a triangular frame design to enhance rigidity, but it does not solve the problem of deep mud sinking; patent CN104986238A uses a pulley mechanism to reduce ground pressure, but it still produces vehicle tilt angle. For example, patent CN207191020U reduces the turning radius through a waist-hinged steering mechanism, but the hydraulic drive system suffers from a design flaw in the sealing structure, resulting in decreased steering accuracy and increased maintenance costs; patent CN106143673A designs four-wheel independent steering combined with RTK navigation, but it will cause positioning drift in complex terrain, requiring manual re-spraying. For example, patent CN105165772A innovatively uses high-voltage electrostatic atomization to improve the droplet deposition rate, but it does not integrate a terrain adaptive mechanism. When operating on slopes, the uniformity of the pesticide solution decreases, and the adhesion effect of the electrostatic field on the crop leaves is significantly affected by humidity. Therefore, it is necessary to design a plant protection vehicle with high stability suitable for complex field environments and an adjustable nozzle adapted to plant types throughout the entire growth period. This will enable stable operation under complex terrain conditions and meet the requirements for precise pesticide application throughout the entire growth period, which has become an urgent need to promote the mechanization of paddy field plant protection machines.

[0007] The aforementioned automated agricultural spraying and plant protection equipment still has many shortcomings in dealing with complex field terrain conditions: (1) Insufficient terrain adaptability: Conventional tracked and wheeled equipment is prone to slipping, vibration, and getting stuck in muddy, pitted, and other places, which affects the stability of operation; (2) Lack of dynamic stability: Non-suspended chassis cause large vehicle vibrations on field ridges and other places, which will lead to a decrease in the uniformity of pesticide application and poor atomization effect, and it is difficult to adapt to the all-round spraying of crops at different growth stages and plant heights and shapes; (3) Low system reliability: The equipment works in an unstable state for a long time, which will increase the cost of maintenance and shorten the service life. Therefore, it is necessary to develop efficient plant protection equipment that is suitable for complex paddy field environments. Utility Model Content

[0008] To address the technical contradiction between terrain adaptability and operational stability in paddy field plant protection operations, this utility model provides a paddy field plant protection vehicle with a dual-stage suspension chassis. The vehicle travels on a triangular track chassis, with the triangular tracks and dual-stage suspension system working in tandem to solve the technical problems of high vehicle stagnation rates, poor adaptability to elevation differences, and low pesticide spraying accuracy in existing equipment. The built-in spring suspension mechanism absorbs vibrations from minor undulations in the field in real time; the external parallelogram four-link suspension adaptively compensates for unilateral elevation differences; and under the coordinated control of these two systems, the vehicle's stagnation rate in muddy paddy fields is significantly reduced.

[0009] Building upon this foundation, the plant protection vehicle integrates a two-axis robotic arm spray system, further enhancing operational precision. The robotic arm, through continuous adjustment of its horizontal rotation joints and flexible swing of its pitch and sway joints, operates with dual degrees of freedom to adapt to the dynamic changes in rice plant structure from tillering to maturity. During the tillering stage, the robotic arm adjusts its posture to match the distribution of upper leaves, achieving comprehensive coverage. During the heading stage, lateral rotation combined with angle adjustment penetrates the upper leaves, precisely targeting the rice panicles. During maturity, where the base is susceptible to disease, reverse rotation and lowering of the angle focus on the basal stems for directional spraying. This structure overcomes the limitations of traditional fixed nozzles or single-degree-of-freedom adjustments. With dual-stage suspension ensuring vehicle stability, it enables directional spraying of target areas throughout the entire crop growth cycle, reducing pesticide waste while significantly increasing target area coverage, forming a complete technological loop of "terrain adaptation, stable driving, and precise application."

[0010] The technical solution of this utility model:

[0011] A paddy field plant protection machine with a dual-stage suspension tracked chassis, the paddy field plant protection machine includes a chassis device (1), a two-axis robotic arm spraying device (2), and a DC drive motor (3).

[0012] The chassis device (1) includes an internal suspension device (11) and an external suspension device (12); the two can respectively achieve buffering of small terrain elevation differences and large terrain elevation differences;

[0013] The two-axis robotic arm spraying device (2) relies on the horizontal rotation joint and the pitch swing arm joint to cover the changes in plant shape throughout the entire growth period of crops and achieve precise application of pesticides to the target parts;

[0014] The DC drive motor (3) provides power for the track to move. By setting different speeds on both sides (preferably differential control), steering can be achieved, ensuring traction on muddy roads and turning flexibility in small fields.

[0015] Furthermore, the built-in suspension device (11) consists of two sets, each set including a triangular track (111), a load-bearing wheel (112), two guide wheels (113), an inner suspension sleeve (114), a straight plate connector (115), two driven wheels (116), an inner suspension shaft (117), two T-shaped connectors (118), and two perforated flat plate connectors (119); the axles of the load-bearing wheel (112) and the two guide wheels (113) are fixed to the track bracket (123); the triangular track (111) covers the outer periphery of the load-bearing wheel (112) and the two guide wheels (113); the outer end of the inner suspension sleeve (114) is fixed to the track bracket (123), and is rotatably connected to the first connection point of the T-shaped connector (118) on its corresponding side; the outer end of the inner suspension shaft (117) is fixed to the track bracket (123), and is rotatably connected to the first connection point of the T-shaped connector (118) on its corresponding side. The first connection point of the T-shaped connector (118) is rotatably connected; the inner end of the inner suspension shaft (117) is inserted into the circular shaft hole at the inner end of the inner suspension sleeve (114), and the two are in clearance fit; the second connection points of the two T-shaped connectors (118) are rotatably connected to the two perforated flat plate connectors (119) on the left and right respectively; the third connection points of the two T-shaped connectors (118) are rotatably connected to both ends of the straight plate connector (115) respectively; the two perforated flat plate connectors (119) are also rotatably connected to the two driven wheels (116) on the left and right respectively and the guide wheel (113); the guide wheel (113) and the driven wheel (116) are assembled at the bottom corner of the triangular track (111); the two form a transmission fit through the triangular track (111), and the guide wheel (113) meshes with the inner side of the triangular track (111) and passively rotates synchronously with the closed-loop transmission of the triangular track (111).

[0016] Furthermore, the axles of the load-bearing wheel (112) and the two guide wheels (113) form an equilateral triangle.

[0017] Furthermore, the external suspension device (12) includes a parallel linkage mechanism (121), a bushing connection assembly (122), a track support (123), a cylinder assembly (124), and a central frame (125). The parallel linkage mechanisms (121) are arranged in pairs, rotatably connected between the inner sides of the left and right track supports (123) and the central frame (125) through the bushing connection assembly (122). Each pair of parallel linkage mechanisms (121) is distributed in a parallelogram shape, forming a single-degree-of-freedom planar motion mechanism. The cylinder assembly (124) adopts a double-acting hydraulic cylinder, with its cylinder bottom hinged to the central frame (125) and its piston rod top welded to the middle connecting rod of the parallel linkage mechanism (121). During operation, the cylinder assembly (124) provides rigid support and damping for the parallel linkage mechanism (121) on the one hand, and enhances the buffering flexibility of the suspension system on the other hand, effectively buffering the impact of obstacles such as track ridges.

[0018] Furthermore, the two-axis robotic arm spraying device (2) includes a nozzle (21), a pitch swing arm joint (22), a horizontal rotation joint (23), a robotic arm base (24), and a water tank (25). The robotic arm base (24) is fixed on the central frame (125), and the horizontal rotation joint (23) is located on the upper end of the robotic arm base (24). It has a built-in 360° continuous rotation servo motor, which can realize multi-level angular velocity adjustment within a 360° range relative to the robotic arm base (24). The pitch swing arm joint (22) is located on the upper end of the horizontal rotation joint (23). The pitch swing arm joint (22) is driven by a servo motor, which can realize multi-attitude adjustment of the pitch angle. The nozzle (21) is fixed on the upper end of the pitch swing arm joint (22). The water tank (25) is connected to the nozzle (21) through a pipe.

[0019] Furthermore, the nozzle (21) is a fan-shaped atomizing nozzle.

[0020] The effects and benefits of this utility model:

[0021] This utility model's dual-stage suspension tracked plant protection machine features a triangular track chassis that reduces ground pressure and soil compaction over a large ground contact area, protecting the topsoil layer of paddy fields. It also significantly improves traversability in muddy paddy terrain, reducing the probability of getting stuck, ensuring continuous and stable operation, and avoiding risks such as spray deviation and equipment damage caused by terrain bumps. Combined with a dual-stage suspension system: an internal elastic suspension absorbs vibrations from minor terrain undulations, reducing vehicle sway; an external rigid suspension compensates for ground elevation differences, ensuring stable track ground contact area, significantly reducing the rate of getting stuck, and adapting to complex paddy field environments such as muddy fields, slopes, and small plots.

[0022] This utility model's dual-stage suspended tracked plant protection machine features a two-axis precision spraying robotic arm that can be adjusted by horizontal rotation and pitch angle to customize its posture throughout the growing season. This allows for all-around, multi-angle spraying, adapting to different growth stages, plant heights, and shapes. It targets specific parts of the crop, including the lower, hidden leaves and rootstocks, enabling directional spraying of pesticides. This ensures uniform pesticide application to all parts of the plant, meeting comprehensive protection needs, while also allowing for precise application to vulnerable areas susceptible to pests and diseases, improving pesticide utilization and reducing waste and environmental pollution. Attached Figure Description

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0024] Figure 1 This is a front view of the overall structure of a dual-stage suspension tracked paddy field plant protection machine.

[0025] Figure 2 This is a left view of the overall structure of a dual-stage suspension tracked paddy field plant protection machine.

[0026] Figure 3 This is a schematic diagram of an external suspension structure.

[0027] Figure 4 This is a schematic diagram of the built-in suspension device.

[0028] Figure 5 This is a schematic diagram of the assembly of the built-in suspension device and tracks.

[0029] Figure 6 This is a schematic diagram of the assembly of the guide wheel and the driven wheel.

[0030] In the diagram: 1-Chassis assembly; 11-Built-in suspension device; 111-Triangular track; 112-Load-bearing roller; 113-Guide wheel; 114-Inner suspension sleeve; 115-Straight plate connector; 116-Driven wheel; 117-Inner suspension shaft; 118-T-type connector; 119-Penetrating flat connector; 12-External suspension device; 121-Parallel linkage mechanism; 122-Busset connection assembly; 123-Track bracket; 124-Hydraulic cylinder assembly; 125-Central frame. 2-Two-axis robotic arm spraying device; 21-Sprayer head; 22-Pitch swing arm joint; 23-Horizontal rotation joint; 24-Robotic arm base; 25-Water tank. 3-DC drive motor. Detailed Implementation Plan

[0031] The technical solutions of the present utility model will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0032] The paddy field plant protection machine of this utility model consists of a dual-stage suspension track system, a two-axis precision spraying robotic arm and a frame; wherein, the dual-stage suspension track system includes multiple sets of load-bearing wheels, built-in elastic suspension components, external rigid suspension components and triangular drive tracks, and the two-axis precision spraying robotic arm integrates a nozzle module and a two-degree-of-freedom motion joint.

[0033] The first aspect of this utility model provides a dual-stage suspension track system, comprising: a built-in elastic suspension assembly, an external rigid suspension assembly, and a triangular track chassis; the built-in elastic suspension assembly is connected to the load-bearing wheel assembly via a hinged arm and adopts a spring-rocker arm type shock absorption structure. The external rigid suspension assembly is hinged to the main frame and the track support via a parallelogram linkage, and the triangular track chassis forms an equilateral triangular closed-loop structure around the guide wheel.

[0034] The built-in elastic suspension assembly is a spring-rocker arm type shock absorption structure, which allows the track to absorb vibrations through spring deformation and simultaneously achieve track tension when the terrain is uneven; the external rigid suspension assembly is a parallelogram linkage mechanism, which allows the track support to compensate for terrain differences and prevent the track from derailing.

[0035] The second aspect of this utility model provides a two-axis spraying robotic arm, comprising: a two-axis robotic arm, a nozzle module, and a water tank; the nozzle module is connected to the end of the two-axis robotic arm, and the two-axis robotic arm is mounted on the main frame via a rotating base and a pitch joint; wherein, the two-axis robotic arm includes a horizontal rotation joint and a pitch rotation joint, and can flexibly adjust the working angle to cover the entire area of ​​crop growth.

[0036] The third aspect of this utility model provides a paddy field plant protection machine with a dual-stage suspension chassis, comprising: a frame and a dual-stage suspension track system and an all-around spraying device mounted on the frame; the dual-stage suspension track system is connected to the bottom of the frame, and the all-around spraying device is mounted on the top of the frame.

[0037] refer to Figure 1 and Figure 2 , Figure 1 This is a front view of the overall structure of the dual-stage suspension tracked paddy field plant protection machine. Figure 2 This is a left view of the overall structure of the dual-stage suspension tracked paddy field plant protection machine. The dual-stage suspension tracked paddy field plant protection machine of this utility model includes a chassis unit 1, a two-axis robotic arm spraying device 2, and a DC drive motor 3. All modules are mechanically connected and functionally coordinated through a central frame 125. The chassis unit 1 is the core of the machine's movement and load-bearing capacity, including an internal suspension device 11 and an external suspension device 12. These two components form a "dual-stage buffer" mechanism to cope with minor terrain undulations, field ridges, and deep ditches, respectively, solving the problems of frequent getting stuck and instability in traditional equipment. The two-axis robotic arm spraying device 2 is installed on top of the central frame 125, relying on horizontal rotation and pitching arm joints to cover the entire growth period of the crop and achieve precise application of pesticides to the target areas. The DC drive motor 3 provides power for the track movement and, in conjunction with differential control, enables steering, ensuring traction on muddy roads and maneuverability in small fields. The machine is suitable for hilly and plain paddy fields, and is especially suitable for complex plots containing field ridges, shallow ditches, and muddy areas. The built-in suspension device 11 consists of a triangular track 111, a load-bearing wheel 112, a guide wheel 113, an inner suspension sleeve 114, a connecting assembly 115, a driven wheel 116, and an inner suspension axle 117. Its core function is to absorb minor terrain vibrations and maintain track ground stability, solving problems such as getting stuck in mud, high-frequency vibration of the vehicle body, and vibration instability. The triangular track 111 is preferably an equilateral triangular closed-loop structure to solve the problem of instability when crossing obstacles caused by the shift of the center of gravity.

[0038] Each triangular track 111 is equipped with one load-bearing roller 112. The entire machine has two load-bearing rollers 112, corresponding to the left and right triangular tracks 111 respectively. The load-bearing rollers 112, together with the guide wheels 113 and driven wheels 116 at the two bottom corners of the triangular track 111, form the closed-loop travel frame of the triangular track 111. The guide wheels 113 and driven wheels 116 are assembled at the bottom corners of the triangular track 111, forming a transmission connection through the closed-loop track of the triangular track 111. The configuration relationship between the triangular track 111 and the load-bearing rollers 112 is one-to-one. The single track single load-bearing roller design can concentrate and evenly distribute the force on the triangular track 111, effectively avoiding track sinking caused by local overload, and ensuring stable contact between the track and the ground.

[0039] The load-bearing roller 112 is connected to the inner suspension sleeve 114 via the inner suspension shaft 117 to prevent localized sinking. The inner suspension sleeve 114 incorporates a spring-rocker arm shock-absorbing structure. When the track encounters slight terrain undulations, such as soil protrusions or shallow ditches, the spring absorbs impact energy through deformation, while the rocker arm synchronously adjusts the angle of the load-bearing roller, ensuring the track remains in contact with the ground and reducing the impact of vibration on spraying accuracy. In actual operation, this structure keeps the vehicle's pitch angle fluctuation within an acceptable range, ensuring spraying accuracy. The guide wheel 113 and driven wheel 116 are located at the front and rear ends of the triangular track 111, respectively, responsible for guiding track steering and adjusting tension to prevent track slack or slippage during travel. The guide wheel 113 and the load-bearing roller 112 form an equilateral triangle, allowing easy crossing of obstacles such as field ridges. When crossing obstacles, the track contact length remains stable, ensuring stable power transmission.

[0040] The inner suspension sleeve 114 is fixed to the inner side of the track bracket 123 by bolts. A circular central hole, adapted to the inner suspension shaft 117, is provided at its center, serving as a load-bearing and component connection point. The inner suspension shaft 117 passes horizontally through the central hole of the inner suspension sleeve 114. The two are fitted with a clearance fit, which avoids rotational jamming caused by an interference fit and prevents radial displacement of the inner suspension shaft 117 under load through the radial constraint of the central hole of the inner suspension sleeve 114. One end of the shaft 117 extends from the central hole of the inner suspension sleeve 114, and its extended end forms a rotatable connection with the first connection point of the right-side T-type connector 118 through a deep groove ball bearing. When the inner suspension shaft 117 receives the load transmitted by the right-side T-type connector 118, the load can be stably transferred to the inner suspension sleeve 114 through the mating surface with the central hole of the inner suspension sleeve 114, and then transmitted from 114 to the track bracket 123, thus taking into account both the rotation function of the inner suspension shaft 117 and the overall stability of the inner suspension sleeve 114.

[0041] The built-in suspension device has two T-shaped connectors 118 on the left and right. The first connection point of the left T-shaped connector 118 is rotatably connected to one end of the inner suspension sleeve 114 via a hinge, allowing for rotational allowance to adapt to terrain undulations. The second connection point of the left T-shaped connector 118 is rotatably connected to the left end of the straight plate connector 115 via a pin. The built-in suspension device also has two perforated flat plate connectors 119 on the left and right. The third connection point of the left T-shaped connector 118 is rotatably connected to one end of the perforated flat plate connector 119 via a deep groove ball bearing. The first connection point of the right T-shaped connector 118 is rotatably connected to the extended end of the inner suspension shaft 117 via a deep groove ball bearing; the second connection point is rotatably connected to the right end of the straight plate 115 via a pin; and the third connection point is rotatably connected to the other end of the perforated flat plate connector 119 via a deep groove ball bearing.

[0042] The straight-plate connector 115 has a flat, horizontally distributed structure and serves as the connection point for the left and right T-shaped connectors 118. Its two ends are connected to the second connection points of the two T-shaped connectors 118 via pins, forming a rotatable connection. This, combined with the symmetrical structure, ensures that uneven force distribution caused by unilateral offset is avoided when adjusting the machine's posture. The other two mounting holes of the perforated flat-plate connector 119 are rotatably connected to the axles of the guide wheel 113 and driven wheel 116 via deep groove ball bearings, providing fitting space between the guide wheel 113 and driven wheel 116.

[0043] The built-in suspension system achieves a buffer function based on the connection relationship of core components. When the track encounters slight terrain undulations such as soil bulges and shallow ditches during operation, the clearance fit between the inner suspension shaft 117 and the inner suspension sleeve 114, the rotational connection between the left and right T-shaped connectors 118 and the inner suspension shaft 117 and the inner suspension sleeve 114, and the flexible connection between the straight plate connector 115 and the left and right T-shaped connectors 118 can jointly absorb external impact energy, effectively control the vibration amplitude of the vehicle body, avoid the spraying deviation of the nozzle 21 caused by vibration, and ensure the accuracy of pesticide application.

[0044] The guide wheel 113 and driven wheel 116 are mounted at the base corner of the triangular track 111, forming a transmission connection through the triangular track 111. They respectively undertake the functions of track steering guidance and tension adjustment. The axle of the driven wheel 116 is rotatably connected to the other end of the perforated flat plate connector 119 via a deep groove ball bearing. The axle of the guide wheel 113 is fixed to the front end of the track bracket 123 by welding, and its axle is also rotatably connected to one end of the perforated flat plate connector 119 via a deep groove ball bearing. This allows it to oscillate with the perforated flat plate connector 119 to adapt to changes in track posture. Furthermore, this angle perfectly matches the equilateral triangular closed-loop structure of the triangular track 111, ensuring that the tilt angle of the guide wheel synergizes with the geometric angles of the track frame. When the equipment crosses obstacles such as field ridges, the guide wheel can make contact with the obstacle first and generate a uniform upward climbing force, avoiding force offset or localized overload problems caused by the inconsistent angles and side lengths of the isosceles triangle. At the same time, the symmetrical structure of the equilateral triangle can avoid the grounding instability caused by the large fluctuation of the grounding side length with rotation in the isosceles triangle, and avoid the risk of power interruption or derailment caused by sudden changes in grounding length.

[0045] Continue to refer to Figure 1 and Figure 2 The two-axis robotic arm spraying device 2 focuses on the differences in crop plant shape and application sites, including a nozzle 21, a pitch and swing arm joint 22, a horizontal rotation joint 23, a robotic arm base 24, and a water tank 25. It achieves customized application throughout the growth period through dual-degree-of-freedom adjustment, thus enabling full-plant coverage. The robotic arm base 24 is bolted to the central frame 125. The horizontal rotation joint 23 has a built-in 360° continuous rotation servo motor, allowing for multi-level angular velocity adjustment and response time matching the work rhythm to ensure continuous application. The pitch and swing arm joint 22 is also driven by a servo motor, enabling multi-position adjustment of the nozzle robotic arm's pitch angle, and the swing arm length adapts to the plant height changes from tillering to maturity. Together, these two components allow the nozzle 21 to cover multiple plants per row and multiple application sites per plant. The nozzle 21 uses a fan-shaped atomization pattern, ensuring good uniformity of pesticide application on the crop leaves. The water tank 25 has a rectangular structure and provides continuous spraying of medicine throughout the operation. It is connected to the nozzle 21 through a pipe.

[0046] The precise spraying logic for different growth stages of rice is as follows: Tillering stage (plant height 30-50cm): The horizontal rotation joint 23 is kept in the middle position, and the pitching arm joint 22 is adjusted to a downward tilt position to achieve wide-area spraying, covering the upper leaves and stems; Heading stage (plant height 80-120cm): The horizontal rotation joint 23 is rotated to the side, and the pitching arm joint 22 is adjusted to an upward tilt position, allowing the nozzle to penetrate deep into the lower layer and precisely spray the flag leaf and rice panicle, reducing shading and missed spraying; Maturity stage (plant height 120-150cm): The horizontal rotation joint 23 is rotated to the opposite direction, and the pitching arm joint 22 is adjusted to a downward tilt position, focusing on spraying the base.

[0047] refer to Figure 3 Schematic diagram of external suspension structure. Figure 3 As shown, the external suspension device 12 includes a parallel linkage mechanism 121, a bushing connection assembly 122, a track support 123, a cylinder assembly 124, and a central frame 125. It is used to compensate for significant terrain elevation differences. The core mechanism uses rigid linkages and buffers to prevent derailment and tilting caused by field ridges and deep ditches. The parallel linkage mechanism 121 consists of four high-strength aluminum alloy linkages arranged in a parallelogram. These linkages are hinged to the track support 123 and the central frame 125 via the bushing connection assembly 122, forming a single-degree-of-freedom planar motion mechanism. When there is a large difference in ground elevation, such as in terraced fields or ditches, the linkages cause the track support 123 to float horizontally relative to the central frame 125, allowing the left and right tracks to conform to different ground heights. For example, when the left track encounters a 30mm protrusion, the left linkage rises while the right track remains in place, preventing uneven pesticide distribution caused by nozzle tilting. The cylinder assembly 124 adopts a double-acting hydraulic cylinder, which dynamically adjusts the suspension stiffness through hydraulic oil pressure to improve buffer flexibility. The cylinder provides rigid support and damping for the connecting rod, effectively reducing the risk of derailment.

[0048] The DC drive motor 3 provides power for the track movement. Two DC motors are used to drive the left and right triangular tracks 111 respectively to achieve differential steering, which meets the needs of flexible steering and muddy traction in the rice paddy (row spacing 30-40cm).

[0049] This utility model's dual-stage suspension chassis-based paddy field plant protection machine performs pesticide spraying operations, including the following steps:

[0050] Step 1: Liquid Storage Adjustment and Equipment Initialization

[0051] According to the target pest type, fill the water tank 25 with the prepared pesticide solution; start the DC drive motor 3, and at the same time activate the servo control system of the two-axis robotic arm spraying device 2 to return the horizontal rotation joint 23 to zero and the pitch swing arm joint 22 to zero, ensuring that the initial posture of the nozzle 21 is positive and horizontal.

[0052] Step 2: Dual-stage suspension pre-adaptation

[0053] By observing the terrain features such as field ridges and shallow ditches, the pressure of the hydraulic cylinder assembly 124 of the external suspension device 12 is pre-adjusted;

[0054] The process can include a path planning function to plan a zigzag operation path based on the rice planting row direction (default row spacing 30-40cm) to ensure no missed areas are sprayed.

[0055] Step 3: Customized adjustment of the two-axis robotic arm's posture

[0056] Adjust the robotic arm posture according to the rice growth stage and target application site: Tillering stage (plant height 30-50cm): Keep the horizontal rotation joint 23 at 0°, and adjust the pitch and swing arm joint 22 to the downward angle to cover the upper leaves and stems; Heading stage (plant height 80-120cm): Rotate the horizontal rotation joint 23 to the side, and adjust the pitch and swing arm joint 22 to the upward angle, so that the nozzle 21 penetrates into the lower layer of the crop and is aimed at the flag leaf and rice ear; Maturity stage (plant height 120-150cm): Rotate the horizontal rotation joint 23 to the opposite direction, and adjust the pitch and swing arm joint 22 to the downward angle to focus on spraying the basal stems and the area around the roots.

[0057] Step 4: Spraying and Dynamic Terrain Response

[0058] The booster pump is started, and the liquid medicine is delivered to the nozzle 21 through the corrosion-resistant pipe. The DC drive motor 3 rotates to move the track. The spring-rocker arm structure of the built-in suspension device 11 absorbs small undulations in real time, and the parallel linkage mechanism 121 of the external suspension device 12 can cope with working environments such as field ridges, terraced fields and mud ditches.

[0059] Step 5: Finishing the Work

[0060] Return operation: After the operation is completed, the robotic arm automatically returns to zero and enters low-power standby mode;

[0061] This method achieves terrain adaptation through dual-stage suspension and specific posture adjustment through a two-axis robotic arm, enabling plant protection operations throughout the entire rice growth period. It significantly improves pesticide utilization and operational efficiency, and noticeably reduces soil compaction, effectively solving the three major pain points of "vehicle getting stuck, missed spraying, and pesticide waste" in muddy paddy fields.

Claims

1. A paddy field plant protection machine with a dual-stage suspension tracked chassis, characterized in that, The paddy field plant protection machine includes a chassis device (1), a two-axis robotic arm spraying device (2), and a DC drive motor (3). The chassis device (1) includes an internal suspension device (11) and an external suspension device (12); the two can respectively achieve buffering of small terrain elevation differences and large terrain elevation differences; The two-axis robotic arm spraying device (2) relies on the horizontal rotation joint and the pitch swing arm joint to cover the changes in plant shape throughout the entire growth period of crops and achieve precise application of pesticides to the target parts; The DC drive motor (3) provides power for the track movement.

2. The paddy field plant protection machine with a dual-stage suspension tracked chassis according to claim 1, characterized in that, The built-in suspension device (11) consists of two sets, each set including a triangular track (111), a load-bearing wheel (112), two guide wheels (113), an inner suspension sleeve (114), a straight plate connector (115), two driven wheels (116), an inner suspension shaft (117), two T-shaped connectors (118), and two perforated flat plate connectors (119). The axles of the load-bearing wheel (112) and the two guide wheels (113) are fixed to the track bracket (123). The triangular track (111) covers the outer periphery of the load-bearing wheel (112) and the two guide wheels (113). The outer end of the inner suspension sleeve (114) is fixed to the track bracket (123) and is rotatably connected to the first connection point of the T-shaped connector (118) on its corresponding side. The outer end of the inner suspension shaft (117) is fixed to the track bracket (123) and is rotatably connected to the first connection point of the T-shaped connector (118) on its corresponding side. The first connection point of the connector (118) is rotatably connected; the inner end of the inner suspension shaft (117) is inserted into the circular shaft hole at the inner end of the inner suspension sleeve (114), and the two are in clearance fit; the second connection points of the two T-shaped connectors (118) are rotatably connected to the two perforated flat connectors (119) on the left and right respectively; the third connection points of the two T-shaped connectors (118) are rotatably connected to the two ends of the straight plate connector (115) respectively; the two perforated flat connectors (119) are also rotatably connected to the two driven wheels (116) on the left and right respectively and the guide wheel (113); the guide wheel (113) and the driven wheel (116) are assembled at the bottom corner of the triangular track (111); the two form a transmission fit through the triangular track (111), and the guide wheel (113) meshes with the inner side of the triangular track (111) and passively rotates synchronously with the closed-loop transmission of the triangular track (111).

3. A paddy field plant protection machine with a dual-stage suspension tracked chassis according to claim 2, characterized in that, The axles of the load-bearing wheel (112) and the two guide wheels (113) form an equilateral triangle.

4. A paddy field plant protection machine with a dual-stage suspension tracked chassis according to claim 1, characterized in that, The external suspension device (12) includes a parallel linkage mechanism (121), a bushing connection assembly (122), a track support (123), a cylinder assembly (124), and a central frame (125). The parallel linkage mechanisms (121) are arranged in pairs and are rotatably connected to the inner side of the left and right track supports (123) and the central frame (125) through the bushing connection assembly (122). Each pair of parallel linkage mechanisms (121) is distributed in a parallelogram shape to form a single-degree-of-freedom planar motion mechanism. The cylinder assembly (124) adopts a double-acting hydraulic cylinder. The bottom of its cylinder is hinged to the central frame (125), and the top of its piston rod is welded to the middle connecting rod of the parallel linkage mechanism (121). During operation, the cylinder assembly (124) provides rigid support and damping for the parallel linkage mechanism (121) on the one hand, and enhances the buffering flexibility of the suspension system on the other hand, which can effectively buffer the impact of obstacles such as track ridges.

5. A paddy field plant protection machine with a dual-stage suspension tracked chassis according to claim 1, characterized in that, The two-axis robotic arm spraying device (2) includes a nozzle (21), a pitch swing arm joint (22), a horizontal rotation joint (23), a robotic arm base (24), and a water tank (25). The robotic arm base (24) is fixed on the central frame (125). The horizontal rotation joint (23) is located on the upper end of the robotic arm base (24) and has a built-in 360° continuous rotation servo motor, which can realize multi-level angular velocity adjustment within a 360° range relative to the robotic arm base (24). The pitch swing arm joint (22) is located on the upper end of the horizontal rotation joint (23). The pitch swing arm joint (22) is driven by a servo motor and can realize multi-attitude adjustment of pitch angle. The nozzle (21) is fixed on the upper end of the pitch swing arm joint (22). The water tank (25) is connected to the nozzle (21) through a pipe.

6. A paddy field plant protection machine with a dual-stage suspension tracked chassis according to claim 5, characterized in that, The nozzle (21) is a fan-shaped atomizing nozzle.

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