Chassis of small agricultural fertilizer and pesticide spraying robot

Abstract

The invention provides a small agricultural fertilizer and pesticide spraying robot chassis which comprises two chassis bodies arranged in a bilateral symmetry mode. The two groups of cross-row connecting mechanisms are arranged front and back and are fixedly connected with the two chassis machine bodies located on the two sides of the cross-row connecting mechanisms respectively, the cross-row connecting mechanisms are provided with a plurality of groups of adjusting hole positions, and the chassis machine bodies on the two sides are fixed through bolts by selecting different adjusting hole positions to achieve overall transverse variable-pitch adjustment of the robot chassis; the four walking mechanisms are arranged on the chassis bodies on the two sides and close to the mounting positions of the four corners of the whole chassis, each walking mechanism corresponds to one driving wheel, and the driving wheels are located on the outer sides of the chassis bodies and are in transmission connection with the independent driving mechanisms in the chassis bodies; the four sets of steering mechanisms are respectively matched with the four walking mechanisms, so that the driving wheels realize independent steering control; and the targeted pesticide application module is mounted at the front end of the chassis body. The robot chassis is suitable for farmland multi-scene operation and has flexible steering and strong driving force.

Description

Technical Field

[0001] This invention relates to the field of agricultural robot technology, and in particular to a chassis for a small agricultural fertilizer and pesticide spraying robot. Background Technology

[0002] With the promotion and application of precision agriculture and smart agriculture, fertilizer and pesticide spraying operations in farmland are gradually developing from manual spraying to unmanned and precise automatic spraying systems. At present, the chassis structures of small agricultural robots mainly include wheeled structures, tracked structures, and differential speed mobile platforms. However, these structures still have significant shortcomings in the ever-changing farmland environment.

[0003] Traditional differential chassis, while simple in structure, rely on the speed difference between the left and right wheels for steering. This results in poor directional stability and large steering errors in soft, slippery, and uneven terrain, failing to meet the precise path tracking requirements of targeted spraying. While Ackerman steering chassis can achieve conventional vehicle-style steering, its large minimum turning radius makes it difficult to maneuver flexibly in narrow spaces between crop rows. Furthermore, two-wheel drive or front-wheel drive / rear-wheel drive structures are prone to insufficient traction on slippery soil, affecting the continuity of spraying operations.

[0004] Therefore, existing chassis structures are difficult to combine high traction, high mobility, small turning radius and precise steering control, and cannot fully meet the operational needs of fertilizer and pesticide spraying robots in complex fields. Therefore, there is an urgent need for a small spraying robot chassis that is suitable for multiple farmland operation scenarios and has flexible steering and strong driving force. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention provides a small agricultural fertilizer and pesticide spraying robot chassis, which aims to overcome the drawbacks of existing farmland operation chassis, such as insufficient traction, limited steering methods, weak maneuverability, large turning radius, and poor walking stability.

[0006] To achieve the above objectives, the present invention provides a chassis for a small agricultural fertilizer and pesticide spraying robot, comprising:

[0007] Two chassis bodies are arranged symmetrically on the left and right sides;

[0008] Two sets of cross-linking mechanisms are arranged at the front and rear and respectively fixedly connected to the two chassis bodies located on both sides. The cross-linking mechanism is provided with multiple sets of adjustment holes. The chassis bodies on both sides can achieve overall lateral pitch adjustment of the robot chassis by selecting different adjustment holes and fixing them with bolts.

[0009] Four walking mechanisms are respectively arranged on the chassis body on both sides near the four corners of the chassis. Each walking mechanism corresponds to a drive wheel. The drive wheel is located on the outside of the chassis body and is connected to an independent drive mechanism inside the chassis body.

[0010] Four steering mechanisms are arranged in conjunction with the four walking mechanisms to enable independent steering control of the drive wheels;

[0011] The targeted drug delivery module is installed at the front end of the chassis body.

[0012] In some embodiments, the walking mechanism includes:

[0013] The walking drive motor is fixedly mounted on the mounting base of the chassis body;

[0014] The travel drive shaft is supported in the fixed structure of the chassis body by a thrust cylindrical roller bearing, wherein the output shaft of the travel drive motor is coaxially connected to the travel drive shaft by a coupling;

[0015] A right-angle reducer, the input end of which is coaxially connected to the output end of the walking power shaft;

[0016] The walking wheel is fixedly connected to the output end of the right-angle reducer.

[0017] In some embodiments, the steering mechanism includes:

[0018] The steering drive motor is fixedly mounted on the mounting base of the chassis body;

[0019] The speed reducer is configured such that the output shaft of the steering drive motor is connected to the input end of the speed reducer via gears.

[0020] A drive gear, which is fixedly connected to the output end of the reducer;

[0021] A steering gear and a steering shaft, wherein the drive gear meshes with the steering gear for transmission, and the steering gear is coaxially sleeved on the outer circumference of the steering shaft and fixedly connected to the steering shaft;

[0022] An angle sensor is installed on the side of the steering shaft, and the output shaft of the angle sensor is connected to the steering shaft via a coupling.

[0023] In some embodiments, the steering gear is axially positioned on the steering shaft by a shoulder and fasteners; the steering shaft is arranged in a vertical direction, and the lower end of the steering shaft is supported in the fixed structure of the chassis body by a bearing assembly, so that the steering shaft can rotate smoothly relative to the chassis body around its own axis.

[0024] In some embodiments, the targeted drug delivery module includes a spray bar and a plurality of valve-controlled nozzles spaced apart along the length of the spray bar. The spray bar has a main liquid supply pipeline inside, and the valve-controlled nozzles are connected to the main liquid supply pipeline through branch interfaces.

[0025] In some embodiments, the spray bar is slidably connected to a spray bar lifting device via a slide plate connector. The spray bar lifting device drives the slide plate connector to move up and down along the guide structure, thereby achieving height adjustment of the spray bar and the valve-controlled nozzle.

[0026] In some embodiments, the valve-controlled nozzle includes:

[0027] The water inlet and the nozzle body are connected to the liquid inlet channel of the nozzle body;

[0028] An agricultural spray head and a solenoid valve, wherein the solenoid valve is disposed on the flow channel between the water inlet and the agricultural spray head, the valve body of the solenoid valve is fixedly connected to the spray head body, and the agricultural spray head is connected to the liquid outlet end of the spray head body.

[0029] A manual switch is connected to the control mechanism of the nozzle body;

[0030] A nozzle clip is provided between the nozzle body and the spray bar, and the nozzle body is detachably fixed to the spray bar through the nozzle clip.

[0031] In some embodiments, a robot top is disposed above the middle of the cross-connection mechanism, the robot top is fixedly connected to the cross-connection mechanism, and a GNSS navigation device and a CMOS camera are mounted on the robot top.

[0032] In some embodiments, the outer shell of the chassis body is a detachable structure and can be quickly assembled and disassembled through body buckles; the medicine tank and the battery power supply system are respectively arranged in the upper and lower parts of the central internal space of the chassis body.

[0033] In some embodiments, the robot chassis also includes an emergency stop device located at the four corners of the chassis.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The small agricultural fertilizer and pesticide spraying robot chassis provided by this invention has a compact structure and four-wheel independent steering, making it suitable for complex farmland. It has significant technical advantages compared with existing small agricultural robot chassis.

[0036] The four-wheel independent drive structure of the chassis of the small agricultural fertilizer and pesticide spraying robot provided by the present invention significantly improves the robot's traction and passability in complex farmland scenarios, enabling it to operate stably in loose topsoil, muddy, and waterlogged conditions, reducing the risk of slipping and getting stuck.

[0037] The four-wheel independent steering system of the small agricultural fertilizer and pesticide spraying robot chassis provided by this invention has extremely high mobility. Through the combination of multiple steering modes, it realizes small-radius turning, lateral and diagonal movement, and rotation in place, enabling the robot to flexibly pass through narrow spaces between crop rows and accurately reach the spraying target point.

[0038] The small agricultural fertilizer and pesticide spraying robot chassis provided by this invention achieves high-precision steering control through the combination of a precision reduction mechanism and an angle sensor, which significantly improves the positioning accuracy of the nozzle and the target point during spraying operations and effectively enhances the precision of pesticide application.

[0039] The compact structure, reasonable power matching, and stable control system of the small agricultural fertilizer and pesticide spraying robot chassis provided by this invention make the chassis run smoothly and reliably, improving the consistency and automation level of spraying operations. It not only improves the operating efficiency and spraying accuracy of the fertilizer and pesticide spraying robot, but also enhances its ability to adapt to complex field environments, providing reliable chassis technology support for unmanned and intelligent agriculture. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of the chassis of the small agricultural fertilizer and pesticide spraying robot shown in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the walking mechanism shown in an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the steering mechanism shown in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the targeted drug delivery module shown in an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the valve-controlled nozzle shown in an embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram of the climbing mechanism of the chassis of the small agricultural fertilizer and pesticide spraying robot shown in an embodiment of the present invention;

[0046] Figure 7 This is a schematic diagram of the steering mechanism of the chassis of the small agricultural fertilizer and pesticide spraying robot shown in an embodiment of the present invention;

[0047] In the attached figures, the following labels are used:

[0048] 1- Chassis and body;

[0049] 2- Inter-line connection mechanism;

[0050] 3-Drive wheels;

[0051] 40 - Travel drive motor; 41 - Travel power shaft; 42 - Thrust cylindrical roller bearing; 43 - Coupling;

[0052] 44-Right-angle reducer; 45-Walking wheel; 50-Steering drive motor; 51-Reducer; 52-Drive gear; 53-Steering gear; 54-Steering shaft; 55-Angle sensor;

[0053] 60-Spray boom; 61-Valve-controlled nozzle; 611-Water inlet; 612-Nozzle body; 613-Agricultural nozzle; 614-Solenoid valve; 615-Manual switch; 616-Nozzle clip; 62-Slide table connector; 63-Spray boom lifting device;

[0054] 7-Robot Top;

[0055] 8-GNSS navigation device;

[0056] 9-CMOS camera;

[0057] 10-Body latches;

[0058] 11-Medicine kit;

[0059] 12- Battery power supply system;

[0060] 13-Emergency stop device. Detailed Implementation

[0061] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0062] See Figure 1-7 An embodiment of the present invention provides a chassis for a small agricultural fertilizer and pesticide spraying robot, comprising: two chassis bodies 1, which are symmetrically arranged on the left and right; two sets of cross-connection mechanisms 2, which are arranged front and rear and respectively fixedly connected to the two chassis bodies 1 located on both sides, the cross-connection mechanisms 2 having multiple sets of adjustment holes, and the chassis bodies 1 on both sides can achieve overall lateral pitch adjustment of the robot chassis by selecting different adjustment holes for bolt fixing; and four walking mechanisms, which are respectively arranged on the chassis bodies 1 on both sides near the four corners of the chassis and fixed by screws.

[0063] Each of the walking mechanisms corresponds to a drive wheel 3, which is located on the outside of the chassis body 1 and is connected to an independent drive mechanism inside the chassis body 1; four steering mechanisms are arranged in cooperation with the four walking mechanisms respectively, so that the drive wheels 3 can achieve independent steering control;

[0064] The targeted drug delivery module is installed at the front end of the chassis body 1.

[0065] The chassis structure of the small agricultural fertilizer and pesticide spraying robot provided in this embodiment is a symmetrical double-sided body layout. The chassis bodies 1 on both sides are connected as one unit by the cross-linking connection mechanism 2. The two sets of cross-linking connection mechanisms 2 are arranged in front and behind and fixedly connected to the two chassis bodies 1 located on both sides, so as to improve the structural rigidity and cross-linking stability.

[0066] The walking mechanism in this embodiment includes: a walking drive motor 40, fixedly mounted on the mounting base of the chassis body 1; a walking power shaft 41, supported in the fixed structure of the chassis body 1 by a thrust cylindrical roller bearing 42, to bear the axial load generated during walking and ensure that the walking power shaft can rotate smoothly relative to the body; wherein, the output shaft of the walking drive motor 40 and the walking power shaft 41 are coaxially connected by a coupling 43, which is used to compensate for assembly errors and realize torque transmission; a right-angle reducer 44, whose input end The output end of the travel drive shaft 41 is coaxially connected to the travel wheel 45. The output end of the right-angle reducer 44 is fixedly connected to the travel wheel 45, so that the output torque of the travel drive motor 40 is transmitted to the travel drive shaft 41 through the coupling 43, and further reduced and increased in torque by the right-angle reducer 44 to drive the travel wheel 45 to rotate, thereby realizing the travel drive of the whole vehicle. Furthermore, the right-angle reducer 44 adopts bevel gear transmission to transmit the power and torque of the travel drive shaft and change the transmission direction, so that the travel drive motor can drive the travel wheel to rotate.

[0067] In this embodiment, the walking mechanism is mainly powered by a walking drive motor. The power is transmitted through a cylindrical roller bearing to rotate the walking power shaft. The walking power shaft then drives the walking wheels to rotate via a coupling and a right-angle reducer, thereby achieving real-time walking drive for the entire vehicle. Four sets of walking mechanisms are installed inside the robot chassis and fixed with screws. The right-angle reducer transmits the power and torque of the walking power shaft through bevel gears and changes the transmission direction, enabling the motor to drive the walking wheels to rotate.

[0068] The steering mechanism in this embodiment includes: a steering drive motor 50, fixedly mounted on the mounting base of the chassis body 1; a reducer 51, the output shaft of the steering drive motor 50 being connected to the input end of the reducer 51 via gears, the connection method being either a coupling connection or a key connection; a drive gear 52, the drive gear 52 being fixedly connected to the output end of the reducer 51, the drive gear 52 and the output shaft of the reducer 51 being connected via a key connection and using a fastening nut and a locking washer to achieve axial limiting and anti-loosening; a steering gear 53 and a steering shaft 54, the drive gear... Wheel 52 meshes with the steering gear 53, so that the output torque of the steering drive motor 50 is reduced and increased by the reducer 51 and then transmitted to the steering gear 53. The steering gear 53 is coaxially sleeved on the outer circumference of the steering shaft 54 ​​and fixedly connected to the steering shaft 54, so that the rotation of the steering gear 53 can drive the steering shaft 54 ​​to rotate synchronously. Angle sensor 55 is installed on the side of the steering shaft 54. The output shaft of the angle sensor 55 is connected to the steering shaft 54 ​​through a coupling. It is used to detect the steering angle and feed the angle signal back to the controller to realize steering closed-loop control.

[0069] The steering gear 53 is axially positioned on the steering shaft 54 ​​by a shoulder and fasteners to prevent axial movement or disengagement. The steering shaft is arranged vertically, and its lower end is supported in the fixed structure of the chassis body by a bearing assembly, so that the steering shaft can rotate smoothly relative to the chassis body around its own axis. When the steering shaft rotates under the drive of the steering drive motor, the steering component fixedly connected to the steering shaft generates a relative angle, thereby realizing the steering movement of the whole machine.

[0070] In this embodiment, the targeted drug delivery module includes a spray bar 60 and multiple valve-controlled nozzles 61 spaced apart along the length of the spray bar 60. These multiple electromagnetic valve-controlled nozzle units form a multi-point independently controllable spray array. A main liquid supply pipeline is located inside the spray bar 60, and the valve-controlled nozzles 61 are connected to the main liquid supply pipeline via branch interfaces, thereby delivering the drug solution to the corresponding nozzles. The spray bar 60 is slidably connected to a spray bar lifting device 63 via a sliding table connector 62. The spray bar lifting device 63 includes a drive motor and a lead screw transmission mechanism. The drive motor rotates the lead screw to drive the sliding table connector 62 to move up and down along a guide structure, thereby adjusting the height of the spray bar 60 and the valve-controlled nozzles 61.

[0071] The valve-controlled nozzle 61 includes an inlet 611 and a nozzle body 612. The inlet 611 is connected to the liquid inlet channel of the nozzle body 612. The inlet 611 is preferably sealed to the branch pipe of the spray bar 60 via a threaded connection, quick-connect fitting, or hose clamp, and a sealing ring can be provided to ensure the sealing of the connection. An agricultural nozzle 613 and a solenoid valve 614 are included. The solenoid valve 614 is disposed on the flow channel between the inlet 611 and the agricultural nozzle 613. The valve body of the solenoid valve 614 is fixedly connected to the nozzle body 612, and the fixing method is screw connection, snap-fit ​​connection, or integral molding. The agricultural nozzle is connected to the liquid outlet end of the nozzle body, preferably detachably, so as to change the nozzle orifice specification or spray angle according to spraying requirements. A manual switch 615 is connected to the control mechanism of the nozzle body 612. The manual switch 615 allows for manual opening and closing of the flow channel when the solenoid valve fails or requires maintenance and adjustment, creating a redundant control method combining electrical and manual controls. A nozzle clip 616 is located between the nozzle body 612 and the spray bar 60. The nozzle body 612 is detachably fixed to the spray bar 60 via the nozzle clip 616, ensuring reliable positioning of the nozzle unit relative to the spray bar after assembly and facilitating quick disassembly and maintenance.

[0072] In this embodiment, the valve core of the solenoid valve opens the flow channel when energized, allowing the liquid to flow to the agricultural nozzle. When de-energized, it closes the flow channel to cut off the liquid output from the corresponding nozzle, thereby achieving independent start-stop control for each nozzle unit. During operation, the liquid supply system delivers the liquid to the nozzle unit through the inlet. When the solenoid valve is open, the liquid enters the agricultural nozzle through the internal flow channel and is atomized and sprayed out. When the solenoid valve is closed, the corresponding nozzle stops discharging liquid. This selective activation of multiple nozzle units achieves targeted application of pesticides, reducing pesticide application to non-target areas and drift.

[0073] In this embodiment, a robot top 7 is provided above the middle of the cross-connection mechanism 2. The robot top 7 is fixedly connected to the cross-connection mechanism 2. A GNSS navigation device 8 and a CMOS camera 9 are installed on the robot top 7 for positioning, navigation, and work area identification. The outer shell of the chassis body 1 is a detachable structure and can be quickly assembled and disassembled through body buckles 10 for easy maintenance and repair. The medicine tank 11 and the battery power supply system 12 are arranged vertically and vertically in the middle internal space of the chassis body 1 to realize medicine storage and power supply for the whole machine. To ensure operational safety, the robot chassis also includes an emergency stop device 13, which is located at the four corners of the chassis and is used to quickly cut off power / stop the whole machine in abnormal working conditions.

[0074] The small agricultural fertilizer and pesticide spraying robot chassis provided in this embodiment of the invention adopts a four-wheel independent drive and independent steering overall structure layout. The entire chassis consists of the main frame, four walking mechanisms, four steering mechanisms, a battery power supply system, a spray boom lifting device, a CMOS camera, a GNSS navigation device, and a targeted application module. The walking drive system matches the motor power, torque, and reduction ratio based on dynamic calculations. Considering the machine's weight of approximately 650 kg, maximum operating speed of 10 km / h, and a maximum field slope of 25°, the rated power of the single-wheel drive motor is determined to be approximately 1.5 kW through analysis of air resistance, rolling resistance, and slope resistance. Therefore, a 110BM0630-48-Z DC brushless motor is selected as the drive motor, and an NV50 worm gear reducer is used as the transmission device, achieving a wheel-end output torque of 10.6 N·m, thus fully meeting the traction requirements in wet, soft, and heavy-load field environments. The steering mechanism is driven by an independent servo motor, and the speed is reduced and the output torque is increased by a precision planetary reducer. To achieve high-precision steering, the present invention uses a WDD35D4 sliding potentiometer-type angle sensor to detect the steering angle of each wheel in real time. The main controller performs closed-loop control on the angle signal to make the four-wheel steering highly consistent and accurate. Taking into account the calculation results of the static resistance torque of the wheels in the field, the present invention uses an 86BL90-440 servo motor as the steering drive source to ensure smooth steering even when the resistance of the farmland is increased due to the softness of the farmland.

[0075] The chassis of the small agricultural fertilizer and pesticide spraying robot provided in this embodiment adopts a four-wheel independent steering and independent drive (4WS4WD) motion mode. Each wheel is driven by an independent steering and walking motor, which can realize complex movements such as two-wheel steering (Ackerman steering), relative steering, diagonal movement, lateral movement, and stationary turning. When moving in the field crop rows for automatic vision navigation, relative steering is used to reduce the turning radius and improve the robot's maneuverability and flexibility. The four-wheel steering system adopts an electronic control method, which realizes multiple steering modes by controlling the steering angle of each wheel, mainly including two-wheel steering, four-wheel reverse steering, crab steering, and stationary turning.

[0076] The motion control system in this embodiment of the invention is based on the STM32F407ZGT6 microcontroller. It manages four drive motors and four steering motors simultaneously via RS485 bus and MODBUS protocol. It can calculate the driving speed and steering angle of each wheel in real time, thereby realizing multiple modes of movement such as Ackerman, reverse four-wheel steering, crab walking, lateral movement and stationary rotation, which meets the route planning needs of the spraying robot in narrow crop rows and complex terrain.

[0077] The small agricultural fertilizer and pesticide spraying robot chassis provided by this invention overcomes technical defects such as insufficient traction, single steering mode, inability to cross rows, and weak maneuverability. It proposes a compact, powerful, and precise steering solution capable of cross-row movement. By equipping each of the four wheels with an independent drive motor and an independent steering motor, the robot not only has the ability to walk in a straight line, perform Ackerman steering, and turn with a small radius, but also can achieve multiple maneuvering modes such as four-wheel reverse steering, crab walking, lateral movement, and stationary rotation. In particular, by utilizing the crab walking and lateral movement modes, the robot can move across crop rows, thereby directly switching work rows without turning around or detouring, improving spraying efficiency and operational flexibility. This small agricultural fertilizer and pesticide spraying robot chassis is stable in movement, precise in steering, maneuverable, and capable of crossing rows, meeting the diverse needs of precision spraying, targeted application, and unmanned operation in farmland.

[0078] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A chassis for a small agricultural fertilizer and pesticide spraying robot, characterized in that: include: Two chassis bodies are arranged symmetrically on the left and right sides; Two sets of cross-linking mechanisms are arranged at the front and rear and respectively fixedly connected to the two chassis bodies located on both sides. The cross-linking mechanism is provided with multiple sets of adjustment holes. The chassis bodies on both sides can achieve overall lateral pitch adjustment of the robot chassis by selecting different adjustment holes and fixing them with bolts. Four walking mechanisms are respectively arranged on the chassis body on both sides near the four corners of the chassis. Each walking mechanism corresponds to a drive wheel. The drive wheel is located on the outside of the chassis body and is connected to an independent drive mechanism inside the chassis body. Four steering mechanisms are arranged in conjunction with the four walking mechanisms to enable independent steering control of the drive wheels; The targeted drug delivery module is installed at the front end of the chassis body.

2. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 1, characterized in that: include: The walking mechanism includes: The walking drive motor is fixedly mounted on the mounting base of the chassis body; The travel drive shaft is supported in the fixed structure of the chassis body by a thrust cylindrical roller bearing, wherein the output shaft of the travel drive motor is coaxially connected to the travel drive shaft by a coupling; A right-angle reducer, the input end of which is coaxially connected to the output end of the walking power shaft; The walking wheel is fixedly connected to the output end of the right-angle reducer.

3. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 1, characterized in that: The steering mechanism includes: The steering drive motor is fixedly mounted on the mounting base of the chassis body; The speed reducer is configured such that the output shaft of the steering drive motor is connected to the input end of the speed reducer via gears. A drive gear, which is fixedly connected to the output end of the reducer; A steering gear and a steering shaft, wherein the drive gear meshes with the steering gear for transmission, and the steering gear is coaxially sleeved on the outer circumference of the steering shaft and fixedly connected to the steering shaft; An angle sensor is installed on the side of the steering shaft, and the output shaft of the angle sensor is connected to the steering shaft via a coupling.

4. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 3, characterized in that: The steering gear is axially positioned on the steering shaft by a shoulder and fasteners; the steering shaft is arranged in a vertical direction, and the lower end of the steering shaft is supported in the fixed structure of the chassis body by a bearing assembly, so that the steering shaft can rotate smoothly relative to the chassis body around its own axis.

5. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 1, characterized in that: The targeted drug delivery module includes a spray bar and multiple valve-controlled nozzles arranged at intervals along the length of the spray bar. The spray bar has a main liquid supply pipeline inside, and the valve-controlled nozzles are connected to the main liquid supply pipeline through branch interfaces.

6. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 5, characterized in that: The spray bar is slidably connected to a spray bar lifting device via a sliding table connector. The spray bar lifting device drives the sliding table connector to move up and down along the guide structure, thereby realizing the height adjustment of the spray bar and the valve-controlled nozzle.

7. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 5, characterized in that: The valve-controlled nozzle includes: The water inlet and the nozzle body are connected to the liquid inlet channel of the nozzle body; An agricultural spray head and a solenoid valve, wherein the solenoid valve is disposed on the flow channel between the water inlet and the agricultural spray head, the valve body of the solenoid valve is fixedly connected to the spray head body, and the agricultural spray head is connected to the liquid outlet end of the spray head body. A manual switch is connected to the control mechanism of the nozzle body; A nozzle clip is provided between the nozzle body and the spray bar, and the nozzle body is detachably fixed to the spray bar through the nozzle clip.

8. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 1, characterized in that: A robot top is provided above the middle of the cross-connection mechanism. The robot top is fixedly connected to the cross-connection mechanism. A GNSS navigation device and a CMOS camera are installed on the robot top.

9. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 8, characterized in that: The outer shell of the chassis body is a detachable structure and can be quickly assembled and disassembled through body buckles; the medicine tank and battery power supply system are respectively arranged in the upper and lower parts of the central internal space of the chassis body.

10. The chassis of the small agricultural fertilizer and pesticide spraying robot according to claim 1, characterized in that: The robot chassis also includes an emergency stop device, which is located at the four corners of the chassis.

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