Active leveling device of air curtain type spraying rod sprayer and control method of active leveling device

Abstract

The invention belongs to the technical field of agricultural machinery, and particularly relates to an active leveling device of an air curtain type spraying rod sprayer and a control method of the active leveling device, and the active leveling device comprises an electronic module for servo leveling and a mechanical module for limit protection. The core of the device is a microcontroller, and the microcontroller is connected with a first sensor used for detecting the inclination angle in real time and a second sensor triggered by a mechanical structure. Under a conventional working condition, the microcontroller operates in a conventional leveling mode, and accurate and smooth servo leveling is carried out by adopting a PID control algorithm; and when the inclination exceeds the safety limit and triggers the second sensor, the system is automatically switched to an emergency protection mode, the PID algorithm is suspended, and a preset emergency protection program is executed for forced resetting. The precision of electronic servo and the reliability of mechanical protection are organically combined, and high-precision, smooth and rapid servo-level response is provided, so that the spraying rod is accurately maintained in a target posture, and the cost benefit is taken into account.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural machinery, and in particular relates to an active leveling device of an air curtain type spray boom sprayer and a control method thereof. Background Art

[0002] Air curtain boom sprayers, as key agricultural machinery for pesticide spraying, are widely used in a variety of applications, including field crops, lawns, and nurseries. These sprayers feature one or more long-extending booms. This design aims to maximize the coverage width in a single stroke, significantly improving efficiency. To ensure uniform and consistent spraying, the ideal operating state is for the boom to maintain a constant, parallel distance from the target surface below it (such as the crop canopy, the ground, or the workpiece surface) throughout the entire operation.

[0003] However, in practical applications, maintaining the spray boom's absolute horizontality or relative parallelism to the target surface presents significant challenges from multiple perspectives, including persistent tilt caused by static moments and transient tilt caused by dynamic disturbances. Persistent tilt caused by static moments is typically caused by the spray boom being mounted in a cantilever or semi-cantilever configuration, with the boom's support point located near the main body. Due to the boom's considerable mass, gravity generates a persistent moment about the support point, causing the boom's distal end to sag naturally, resulting in a static, persistent tilt. This tilt becomes more pronounced with increasing boom length. Transient tilt caused by dynamic disturbances is typically caused by the spray equipment moving over uneven terrain, such as ridges or slopes. The jolt, roll, and pitch of the vehicle body act as strong dynamic disturbances, transmitting them to the boom. These disturbances are random and high-frequency, causing the boom to experience dramatic, large, and transient tilts, with both magnitude and direction constantly changing.

[0004] Whether it's a continuous tilt caused by static torque or a momentary tilt caused by dynamic disturbances, the end result is a disruption of the parallelism between the spray boom and the target surface. This directly leads to inconsistent spraying distances: on the lower side of the boom, the deposition density of the sprayed material (such as pesticides, water, and paint) will be significantly higher than the standard, potentially causing problems such as pesticide damage, waterlogging, or excessive coating. On the higher side, the deposition density will be far below the standard, resulting in substandard control, irrigation, or spraying results. This unevenness not only seriously affects work quality, but also causes material waste and potential environmental pollution.

[0005] To address this challenge, existing technologies primarily employ leveling solutions of varying complexity. The most basic approach relies on simple spring-damped or passive pendulum structures, which have very limited adjustability and are unable to cope with complex operating conditions. A slightly more advanced approach employs simple electromechanical control, using a mechanical sensor (such as a mercury switch or contactor) to trigger a motor for on / off correction. While these solutions can achieve leveling to a certain extent, their core flaw lies in their crude control methods: significant response delays and dead zones result in jerky and uneven leveling movements, and the leveling process is prone to overshoot and continuous back-and-forth oscillation, making it impossible to accurately and stably maintain the spray boom's position. More advanced solutions employ purely electronic servo systems, utilizing high-precision sensors and complex control algorithms. While these solutions offer superior performance, their high manufacturing and maintenance costs limit their adoption in the mainstream market. Summary of the Invention

[0006] Purpose of the invention: The purpose of the present invention is to address the deficiencies of the prior art and provide an active leveling device for an air curtain type spray boom sprayer and a control method thereof, which provides high-precision, smooth and fast servo-level response to accurately maintain the spray boom in a target posture, avoid oscillation and overshoot, and take into account cost-effectiveness.

[0007] Technical solution: The present invention provides an active leveling device for an air curtain boom sprayer, comprising a mounting frame, a folding frame that can rotate about the mounting frame to achieve leveling, and a reeling assembly for driving the folding frame to rotate; the device also includes: a first sensor, configured to detect in real time the tilt angle of the folding frame to generate a first sensing signal; a second sensor, configured to generate a second sensing signal due to mechanical triggering when the tilt angle of the folding frame exceeds a preset safety threshold, the second sensor comprising a detection plate linked to the folding frame and a circuit contact driven thereby; A microcontroller is electrically connected to the first sensor, the second sensor and the retracting assembly, and the microcontroller is configured to: when only the first sensor signal is received, operate in a conventional leveling mode, in which the first sensor signal is calculated based on a proportional-integral-derivative (PID) control algorithm to generate a continuous control signal to drive the retracting assembly to perform servo leveling; when the second sensor signal is received, switch from the conventional leveling mode to an emergency protection mode, in which the PID control algorithm is suspended and a preset emergency protection program is executed to forcibly drive the retracting assembly to restore the folding frame to within the preset safety threshold.

[0008] To further improve the above technical solution, the first sensor is an inertial measurement unit, and the microcontroller uses a complementary filtering algorithm to fuse the accelerometer and gyroscope data in the inertial measurement unit to calculate the tilt angle.

[0009] Furthermore, the device also includes an H-bridge motor driving module, which is arranged between the microcontroller and the electric reel and is used to receive a pulse width modulation signal output by the microcontroller to achieve continuous speed and direction control of the electric reel.

[0010] Furthermore, the emergency protection procedure includes driving the motorized reel at a preset fixed power.

[0011] Furthermore, the microcontroller is configured to apply a control dead zone in the conventional leveling mode, and not drive the retracting assembly when the error between the tilt angle and the target horizontal angle is less than a preset threshold.

[0012] Furthermore, the parameters of the PID control algorithm are adjustable, and the microcontroller is configured to dynamically adjust the parameters according to driving speed data from an external speed sensor or a GPS module.

[0013] Furthermore, the device also includes a windproof locking assembly, which includes: a threaded groove provided on a fixed rod, a turbine blade threadedly connected to the threaded groove, the turbine blade rotates under the action of wind and moves axially along the threaded groove, a driving plate linked to the turbine blade, a limiting rod driven by the driving plate, a clamping block provided at the end of the limiting rod; and clamping holes respectively provided on the mounting frame and the folding frame for engaging with the clamping block; wherein, when the turbine blade moves under the action of wind, the limiting rod is supported by the driving plate, so that the clamping block is clamped into the clamping hole, thereby achieving physical locking of the mounting frame and the folding frame.

[0014] Furthermore, the device also includes at least one ultrasonic or lidar sensor fixed to the end of the folding frame. In the conventional leveling mode, the microcontroller also performs calculations based on the height data measured by the sensor to achieve terrain-simulating height control.

[0015] Furthermore, the second sensor also includes a limit plate, a sliding rod fixedly connected to the limit plate, a reset spring mounted on the sliding rod, and a limit block provided with a circuit connector; the limit plate is overlapped above the detection plate and can slide vertically in the slide groove, and the circuit contact is fixed at the end of the sliding rod; wherein, when the folding frame is tilted, the detection plate pushes the limit plate upward, driving the sliding rod and the circuit contact to move, so that the circuit contact contacts the circuit connector to generate the second sensing signal, and the reset spring is used to provide a reset force when the folding frame returns to a horizontal state.

[0016] The present invention also provides a control method for active leveling of an air curtain type spray boom sprayer, which is applied to the above device and comprises the following steps: S1: The device is operated in a normal leveling mode, in which: Continuously acquiring a real-time tilt angle of the folding frame through the first sensor; Calculating continuous leveling instructions based on a PID control algorithm and the real-time tilt angle; controlling the reeling assembly according to the leveling instruction to perform servo leveling on the folding frame; S2: continuously monitoring a second sensing signal generated by the second sensor; S3: When the second sensor signal is detected, the device is switched from the normal leveling mode to the emergency protection mode. In this mode, the execution of the PID control algorithm is suspended, and a preset emergency protection program is executed to force the leveling of the folding frame until the second sensor signal disappears.

[0017] Beneficial Effects: Compared with existing technologies, the present invention offers the following advantages: It utilizes an electronic servo leveling module, centered around a high-frequency sampling attitude sensor and a PID control algorithm. The integral term in the PID algorithm continuously accumulates minute static errors caused by gravitational torque and generates a continuous compensating torque, thereby perfectly offsetting the natural droop of the spray boom and enabling it to maintain an absolutely horizontal position stably and over a long period of time. The proportional and differential terms in the PID algorithm enable a rapid and smooth response to high-frequency dynamic disturbances such as ground vibration. The proportional term ensures that the corrective force is proportional to the tilt amplitude, while the differential term predicts the trend of change and applies "braking" in advance, effectively suppressing overshoot and oscillation. Compared to the "on-off" control used in existing technologies, the present invention can precisely control the spray boom's attitude error within a very small range (e.g., ±0.5°), ensuring a highly consistent distance between the spray boom and the crop canopy. This fundamentally addresses the problem of uneven pesticide distribution caused by tilt and significantly improves plant protection effectiveness.

[0018] The present invention adopts a dual redundant design, forming a double insurance of "electronic main control + mechanical backup". Even if the electronic system fails, the reliable mechanical protection layer can still intervene to prevent the equipment from getting out of control and being damaged, greatly improving the reliability of the system in complex agricultural environments; the present invention can automatically judge the working conditions and seamlessly switch between conventional leveling and extreme protection modes, which not only ensures the refinement of daily operations, but also ensures a fast and reliable response in extreme situations.

[0019] The present invention makes full use of the mechanical structure of the original equipment, has low transformation cost, and provides an economical and efficient technical path for the intelligent upgrade of existing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the tilt of the folding stand of the present invention; Figure 2 It is a schematic diagram of the overall structure of the present invention; Figure 3 This is a left-side structural schematic diagram of the folding frame of the present invention; Figure 4 This is a schematic diagram of the folding frame structure from the right side of the present invention; Figure 5 This is a schematic diagram of the turbine blade position structure of the present invention; Figure 6 It is a schematic diagram of a half-section front view of the rotating plate located at the lower end of the present invention; Figure 7 This is a schematic diagram of a half-section structure of the rotating plate located at the lower end of the present invention; Figure 8 This is a half-section schematic diagram of the overall winding wheel of the present invention; Figure 9 This is a schematic diagram of the overall structure of the present invention when viewed from above; Figure 10 for Figure 9 Enlarged schematic diagram of the structure at point A in the middle Figure 11 This is a schematic diagram of the folding stand of the present invention being blown by the wind from a top view; Figure 12 Schematic diagram of the movement principle of the limit rod of the present invention.

[0021] Figure 13 This is a block diagram of the overall technical architecture of the active leveling device of the present invention.

[0022] Figure 14 Flowchart of the active leveling control method of the present invention.

[0023] The accompanying drawings are marked as follows: sprayer 1, spray rod 2, fan 3, air guide cover 4, mounting frame 5, folding frame 6, rotating plate 1 7, rotating plate 2 8, fixing rod 9, limiting rod 10, detection plate 11, limiting plate 12, sliding rod 13, limiting block 14, return spring 15, circuit contact 16, winding wheel 17, electric reel 18, traction rope 19, threaded groove 20, turbine blade 21, driving plate 22; limiting rod 23, clamping block 24, clamping hole 25. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0025] Example 1: Reference Figures 1 to 12 This embodiment illustrates the main mechanical structure of an active leveling device for an air curtain boom sprayer. It comprises a sprayer body 1, to which a pair of foldable, bilaterally symmetrical folding frames 6 are connected via a mounting frame 5 via a rotating assembly. The folding frames 6 are used to support and deploy the long-arm sprayer boom 2 and the wind deflector 4. A reel assembly is located at the upper end of the mounting frame 5. The reel assembly includes a reel wheel 17 and a motorized reel 18 at its axis. One or more traction ropes 19 are secured to the outer end of the folding frame 6 at one end and wound around the motorized reel 18 at the other end. The traction ropes 19 are retracted and released by rotating the motorized reel 18 in both forward and reverse directions, allowing precise adjustment of the pitch of the folding frame 6 around its connection to the mounting frame 5.

[0026] Reference Figures 2 to 5 The rotating assembly enables the folding frame 6 to rotate relative to the mounting frame 5 to realize the deployment and folding of the spraying rod and allows a certain range of pitch adjustment during operation. Figure 2 and Figure 3 As shown, the upper and lower ends of the mounting frame 5 can be fixedly connected to a rotating plate 1 7, and a fixing rod 9 is provided between the two opposing rotating plates 1 7. The two ends of the fixing rod 9 are respectively connected to the folding frame 6 through the rotating plate 2 8, or the folding frame 6 is directly fixed to the rotating plate 2 8, and the rotating plate 2 8 can rotate around the fixing rod 9. In some embodiments, the fixing rod 9 itself can be designed as an electric shaft, which is driven to rotate by an external switch or controller, thereby driving the folding frame 6 from a folded state parallel to the travel direction of the sprayer 1 (for easy transportation) to a working state perpendicular to the travel direction (such as Figure 9 shown).

[0027] Reference Figure 2 、 Figure 3 、 Figure 4 and Figure 8The reeling assembly is the actuator for leveling. A reeling wheel 17 is provided at the upper end of the mounting frame 5. The rotating shaft of the reeling wheel 17 is an electric reel 18. One end of a traction rope 19 is fixed to the outer end of the folding frame 6, and the other end is wound around the electric reel 18. Figure 1 As shown, when the folding frame 6 is tilted (dashed line position), it can be pulled back to the horizontal position (solid line position) by controlling the electric reel 18 to tighten the traction rope 19.

[0028] Reference Figure 6 and Figure 7 As shown, the second sensor is a limit position switch composed of a purely mechanical structure. It includes a detection plate 11 that is linked to the rotating plate 28 of the folding frame 6. The detection plate 11 rotates clockwise around the limit rod 10. When the folding frame 6 tilts, the detection plate 11 is pressed downward. A limit plate 12 that can slide vertically in a slide groove is overlapped above the detection plate 11. A sliding rod 13 is fixed to the limit plate 12, which is equipped with a reset spring 15 to provide a reset force. A circuit contact 16 is fixed to the end of the sliding rod 13. The circuit contact 16 is connected to the circuit link in the limit block 14. When the tilt angle of the folding frame 6 exceeds a preset safety threshold, the detection plate 11 pushes the limit plate 12 upward, driving the sliding rod 13 and the circuit contact 16 to move upward, eventually contacting the circuit link, generating a closed switch signal, which is sent to the microcontroller 27 as the second sensor signal.

[0029] The core of the present invention lies in its dual-sensor, dual-mode control system architecture, the overall block diagram of which is as follows: Figure 13 As shown, the system includes a first sensor 26, a second sensor, a microcontroller 27, and a motor driver module 28. The microcontroller 27 utilizes an STM32F103 microprocessor, communicating with the first sensor 26 via an I2C or SPI bus for high-speed data communication, and receives switching signals from the second sensor. The H-bridge motor driver module 28 acts as a bridge between the microcontroller 27 and the motorized reel 18. It utilizes a BTS7960 to receive PWM control signals from the microcontroller 27 and convert them into a high current sufficient to drive the motorized reel 18, thereby achieving precise and continuous control of its speed and direction.

[0030] The first sensor 26 is a high-precision electronic attitude sensor, preferably a six-axis inertial measurement unit (IMU) (including a three-axis gyroscope and a three-axis accelerometer). This first sensor 26 is securely fixed to the center of the mounting frame 5 and is used to accurately measure the attitude of the mounting frame 5 in real time, thereby indirectly or directly determining the roll angle (i.e., tilt angle) of the folding frame 6 relative to the direction of gravity. During each control cycle, the microcontroller performs the following steps: Read the axial angular velocity data of the gyroscope along the direction of travel of the sprayer , based on the final tilt angle calculated in the previous cycle , by integrating the angular velocity, predict the tilt angle of the current cycle : ; Read the gravity component data of the accelerometer on the vertical and lateral axes, and calculate the absolute tilt angle determined by the gravity field at the current moment through the inverse tangent function This step can provide an absolute angle reference without long-term drift, but it is easily disturbed by the linear acceleration of the vehicle (such as bumps, acceleration and deceleration), generating high-frequency noise; The results of the above two steps are weighted and fused to calculate the final, accurate and stable tilt angle of the current cycle. : In this way, the fusion algorithm forms a digital filter: its high-pass filter part (composed of weights The short-term, high-frequency dynamic response of the gyroscope is trusted, which effectively suppresses the transient noise of the accelerometer; the low-pass filter part (by weight Dominant) trusts the long-term, low-frequency stability of the accelerometer and continuously corrects the integral drift of the gyroscope; it provides the subsequent PID controller with a high-precision tilt angle input with both fast response capability and long-term stability, which is a key technical link in realizing the high-precision, high-smoothness leveling control of the present invention.

[0031] Example 2: Please refer to Figure 5 、 Figure 10 and Figure 12 , the device may also include a completely independent, passive wind lock assembly. Figure 5 The structure of the turbine blade 21 in the assembly is shown, including the threaded groove 20 on the fixing rod 9, the turbine blade 21 threadedly connected to the groove, the driving plate 22 linked to the turbine blade 21, and the limiting rod 23 driven by the driving plate 22. The end of the limiting rod 23 is provided with a clamping block 24. The mounting frame 5 and the folding frame 6 are provided with corresponding clamping holes 25. Figure 11 As shown, when encountering strong wind (the arrow direction is the wind direction), the airflow drives the turbine blade 21 to rotate and move upward along the thread groove 20, and then the two limit rods 23 are opened through the driving piece 22. Figure 12 As shown, the block 24 on the limit rod 23 will be locked into the locking hole 25 on the mounting frame 5 and the folding frame 6, thereby physically locking the two and preventing the folding frame 6 from being blown by strong winds. This process is completely mechanized and does not require electrical control.

[0032] Through the above structure, this embodiment constructs a complete leveling device that integrates high-precision electronic servo control and high-reliability mechanical limit protection.

[0033] Example 3: Please refer to Figure 14 This embodiment provides an active leveling control method applied to the device provided in Example 1. The specific process is as follows: Step S101: System initialization.

[0034] After the device is powered on, the microcontroller 27 executes the initialization procedure. Figure 2 In the structure shown, the operator needs to park the sprayer 1 on a level surface and trigger a "zero point calibration" operation. The microcontroller 27 uses the posture data read from the first sensor 26 at this time as the reference zero point, that is, the target horizontal angle.

[0035] Step S102: Enter and operate in a normal leveling mode.

[0036] During normal operation, as long as no limit trigger signal from the second sensor is detected, the system continues to operate in the normal leveling mode. In this mode, the microcontroller 27 executes the following servo control logic in a 100 Hz frequency cycle: Data Acquisition and Accurate Calculation: The microcontroller 27 reads attitude data from the first sensor 26 in real time. To obtain a precise tilt angle, the program fuses the accelerometer and gyroscope data using a complementary filtering algorithm. To obtain a precise tilt angle that is both responsive to instantaneous changes and robust against long-term drift, the program fuses these two sets of data using a complementary filtering algorithm or a Kalman filtering algorithm.

[0037] PID closed-loop operation: The program compares the calculated real-time tilt angle with the target horizontal angle set in step S101 and calculates the current angle error. This error value is input into a classic proportional-integral-derivative (PID) controller. The PID controller calculates a comprehensive control output based on the preset proportional coefficient (Kp), integral coefficient (Ki), and differential coefficient (Kd). These PID parameters can be preset or adjusted in real time based on different operational requirements (such as ground flatness and driving speed).

[0038] Dead-band Control and PWM Generation: To avoid unnecessary fine-tuning and energy consumption when approaching horizontality, a control dead-band is implemented. When the angle error is less than a preset threshold (e.g., ±0.5°), the PID output is forced to zero. Otherwise, the PID output is converted to a PWM signal with the appropriate duty cycle and polarity.

[0039] Drive execution: The PWM signal is sent to the motor drive module 28, which drives the electric reel 18 to rotate and smoothly adjust the posture of the folding frame 6 through the traction rope 19. This process occurs dynamically, as shown in Figure 1As shown, a possibly tilted folding frame 6 (dashed line position) is constantly corrected back to a horizontal position (solid line position).

[0040] Step S103: Continuous monitoring of limit states.

[0041] In the main program loop, the microcontroller 27 always monitors the signal from the second sensor. The mechanical structure of the second sensor is as follows Figure 5 、 Figure 6 As shown, the triggering principle is that when the folding frame 6 tilts too much, the detection plate 11 is lifted up, and finally the circuit contact 16 is closed.

[0042] Steps S104 and S105: Mode switching and execution of emergency protection procedures.

[0043] If the sprayer experiences a jolt, causing the tilt angle of the folding frame 6 to exceed a preset safety threshold (e.g., ±10°), the second sensor's mechanical mechanism is triggered, causing the system to immediately switch from normal leveling mode to emergency protection mode. In this mode, the microcontroller 27 suspends PID calculations and instead executes a pre-set emergency protection procedure, such as driving the motorized reel 18 at a fixed, high power level to force a reset.

[0044] Upon detecting this signal, the microcontroller 27 immediately switches the system from normal leveling mode to emergency protection mode. In this mode, the program suspends PID calculations and instead executes a pre-defined, simple, and reliable emergency protection routine. This routine instructs the motor driver module 28 to drive the motorized reel 18 at a preset fixed power level (e.g., 50% duty cycle) in the direction opposite to the tilt, providing a strong and rapid reset.

[0045] Step S106: Automatic recovery.

[0046] When the folding frame 6 is pulled back to within the safety threshold under the drive of the emergency protection program, Figure 12 As shown in the schematic diagram of the limit rod's motion principle, the second sensor's mechanical mechanism resets, circuit contact 16 opens, and the second sensor signal disappears. Upon detecting this state, microcontroller 27 stops the emergency protection program and automatically switches the system back to normal leveling mode (step S102), resuming high-precision servo leveling control.

[0047] This method ensures that the device can work efficiently and reliably under various working conditions through intelligent switching between conventional servo leveling and emergency mechanical protection.

[0048] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. An active leveling device for an air curtain sprayer, comprising a mounting frame (5), a folding frame (6) that can rotate around the mounting frame (5) to achieve leveling, and a reeling assembly for driving the folding frame (6) to rotate; characterized in that: The device further comprises: A first sensor (26) is used to detect the tilt angle of the folding frame (6) in real time to generate a first sensing signal; a second sensor, configured to generate a second sensing signal due to mechanical triggering when the tilt angle of the folding frame (6) exceeds a preset safety threshold, the second sensor comprising a detection plate (11) linked to the folding frame (6) and a circuit contact (16) driven thereby; A microcontroller (27) is electrically connected to the first sensor (26), the second sensor and the retracting assembly, and the microcontroller (27) is configured to: when only the first sensor signal is received, operate in a conventional leveling mode, in which the first sensor signal is calculated based on a PID control algorithm to generate a continuous control signal to drive the retracting assembly to perform servo leveling; when the second sensor signal is received, switch from the conventional leveling mode to an emergency protection mode, in which the PID control algorithm is suspended and a preset emergency protection program is executed to force the retracting assembly to restore the folding frame (6) to within the preset safety threshold.

2. The active leveling device for the air curtain spray boom sprayer according to claim 1, characterized in that: The first sensor (26) is an inertial measurement unit, and the microcontroller (27) uses a complementary filtering algorithm to fuse accelerometer and gyroscope data in the inertial measurement unit to calculate the tilt angle.

3. The active leveling device for the air curtain spray boom sprayer according to claim 1, characterized in that: The device further comprises an H-bridge motor driving module (28), which is arranged between the microcontroller (27) and the electric reel (18) and is used to receive a pulse width modulation signal output by the microcontroller (27) to achieve continuous speed and direction control of the electric reel (18).

4. The active leveling device for the air curtain sprayer according to claim 1, characterized in that: The emergency protection procedure includes driving the motorized reel (18) at a preset fixed power.

5. The active leveling device for the air curtain sprayer according to claim 1, characterized in that: The microcontroller (27) is configured to apply a control dead zone in the conventional leveling mode, and not drive the retracting assembly when the error between the tilt angle and the target horizontal angle is less than a preset threshold.

6. The active leveling device for the air curtain sprayer according to claim 1, characterized in that: The parameters of the PID control algorithm are adjustable, and the microcontroller (27) is configured to dynamically adjust the parameters according to the driving speed data from an external speed sensor or a GPS module.

7. The active leveling device for an air curtain boom sprayer according to claim 1, characterized in that: The device further comprises a windproof locking assembly, the windproof locking assembly comprising: a threaded groove (20) provided on the fixing rod (9), a turbine blade (21) threadedly connected to the threaded groove (20), the turbine blade (21) rotating under the action of wind and moving axially along the threaded groove (20), a driving plate (22) linked to the turbine blade (21), a limiting rod (23) driven by the driving plate (22), a clamping block (24) provided at the end of the limiting rod (23); and a clamping hole (25) respectively provided on the mounting frame (5) and the folding frame (6) for engaging with the clamping block (24); When the turbine blade (21) moves under the action of wind, the limiting rod (23) is opened by the driving piece (22), so that the clamping block (24) is clamped into the clamping hole (25), thereby achieving physical locking of the mounting frame (5) and the folding frame (6).

8. The active leveling device for an air curtain boom sprayer according to claim 1, characterized in that: The device further comprises at least one ultrasonic or laser radar sensor fixed to the end of the folding frame (6), and the microcontroller (27) performs calculations based on height data measured by the sensor in a conventional leveling mode to achieve terrain-simulating height control.

9. The active leveling device for an air curtain boom sprayer according to claim 1, characterized in that: The second sensor further comprises a limit plate (12), a sliding rod (13) fixedly connected to the limit plate (12), a return spring (15) sleeved on the sliding rod (13), and a limit block (14) provided with a circuit connector; the limit plate (12) is overlapped above the detection plate (11) and can slide vertically in the slide groove, and the circuit contact (16) is fixed to the end of the sliding rod (13); When the folding frame (6) is tilted, the detection plate (11) pushes the limit plate (12) upward, driving the sliding rod (13) and the circuit contact (16) to move, so that the circuit contact (16) contacts the circuit link to generate the second sensing signal, and the reset spring (15) is used to provide a reset force when the folding frame (6) returns to a horizontal position.

10. A control method for active leveling of an air curtain boom sprayer, applied to the device according to claim 1, characterized in that: The following steps are involved: S1: The device is operated in a normal leveling mode, in which: Continuously acquiring the real-time tilt angle of the folding frame (6) through the first sensor (26); Calculating continuous leveling instructions based on a PID control algorithm and the real-time tilt angle; Controlling the reeling assembly according to the leveling instruction to perform servo leveling on the folding frame (6); S2: continuously monitoring a second sensing signal generated by the second sensor; S3: When the second sensor signal is detected, the device is switched from the conventional leveling mode to the emergency protection mode, in which the execution of the PID control algorithm is suspended and a preset emergency protection program is executed to forcibly level the folding frame (6) until the second sensor signal disappears.

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