Active leveling device of air curtain type spray boom sprayer and control method thereof

Abstract

The present application belongs to the technical field of agricultural machinery, and particularly relates to an active leveling device of a wind curtain type pesticide spraying rod spraying machine and a control method thereof. The active leveling device comprises an electronic module for servo leveling and a mechanical module for limit protection. The core of the active leveling device is a microcontroller connected with a first sensor for real-time detection of an inclination angle and a second sensor triggered by a mechanical structure. In a conventional working condition, the microcontroller operates in a conventional leveling mode, adopts a PID control algorithm to perform accurate and smooth servo leveling. When the inclination exceeds a safety limit to trigger the second sensor, the system is automatically switched to an emergency protection mode, suspends the PID algorithm and executes a preset emergency protection program to perform forced resetting. The present application organically combines the accuracy of electronic servo and the reliability of mechanical protection, provides a high-precision, smooth and fast servo level response to accurately maintain the spraying rod at a target posture and takes into account cost effectiveness.

Description

Technical Field

[0001] This invention belongs to the field of agricultural machinery technology, specifically relating to an active leveling device and its control method for an air curtain type sprayer. Background Technology

[0002] Air curtain sprayers, as key agricultural machinery for pesticide spraying, are widely used in many scenarios such as field crops, lawns, and nurseries. The structural feature of this sprayer is that it has one or more long-extending spray booms. This design aims to cover the widest possible working width in a single stroke, thereby greatly improving work efficiency. To ensure uniformity and consistency of spraying, an ideal operating condition is that the spray boom maintains a constant and parallel distance to the target surface (such as crop canopy, ground, or workpiece surface) throughout the entire operation.

[0003] However, in practical applications, maintaining the absolute horizontality of the spray boom or its relative parallelism to the target surface faces severe challenges from multiple aspects, including persistent tilting caused by static torque and transient tilting caused by dynamic disturbances. Persistent tilting caused by static torque is typically generated when the spray boom is cantilevered or semi-cantilevered, with the end closest to the main body of the equipment as the support point. Because the spray boom itself has considerable mass, gravity generates a persistent torque rotating around the support point. This torque causes the end of the spray boom furthest from the support point to sag naturally, forming a static, persistent tilt. This tilt becomes more pronounced with increasing spray boom length. Transient tilting caused by dynamic disturbances usually occurs when the spraying equipment moves on uneven ground (such as field ridges or slopes). The bumps, swaying, and pitching of the vehicle body are transmitted to the spray boom as a strong dynamic disturbance. This disturbance is random and high-frequency, causing the spray boom to tilt violently and significantly in a transient manner, with both its amplitude and direction constantly changing.

[0004] Whether the tilt is a persistent tilt caused by static torque or a momentary tilt caused by dynamic disturbance, the end result is the disruption of the parallel relationship between the spray boom and the target surface. This directly leads to inconsistent spraying distances: on the lower side of the tilted spray boom, the deposition density of the sprayed material (such as pesticides, water, and paint) will be significantly higher than the standard value, potentially causing problems such as pesticide damage, waterlogging, or excessively thick coatings; while on the higher side, the deposition density will be far lower than the standard value, resulting in substandard control / irrigation / spraying effects. This unevenness not only seriously affects the quality of operations but also causes material waste and potential environmental pollution.

[0005] To address this challenge, existing technologies primarily employ leveling schemes of varying complexity. The most basic scheme relies on simple spring damping or passive pendulum structures, whose adjustment capabilities are very limited and ill-suited for complex operating conditions. A slightly more advanced scheme uses simplified electromechanical control, triggering a motor for "on / off" correction via mechanical induction switches (such as mercury switches or contact switches). While this type of scheme can achieve leveling to some extent, its core flaw lies in its overly coarse control method: noticeable response delays and dead zones, abrupt and uneven leveling movements, and a high tendency to overshoot and continuous back-and-forth oscillations during correction, making it impossible to maintain the spray boom's posture accurately and stably. More advanced schemes directly employ purely electronic servo systems, utilizing high-precision sensors and complex control algorithms. While offering superior performance, their high manufacturing and maintenance costs limit their application in the mainstream market. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to address the shortcomings of existing technologies by providing an active leveling device and control method for an air curtain type spray bar sprayer, which provides high-precision, smooth and fast servo-level response to accurately maintain the spray bar in the target posture, avoid oscillation and overshoot, and take cost-effectiveness into account.

[0007] Technical solution: The present invention provides an active leveling device for an air curtain type sprayer, comprising a mounting frame, a folding frame rotatable around the mounting frame for leveling, and a retraction assembly for driving the folding frame to rotate; the device further includes: A first sensor is used to detect the tilt angle of the folding frame in real time to generate a first sensing signal; The second sensor is used to generate a second sensing signal by mechanical triggering when the tilt angle of the folding frame exceeds a preset safety threshold. The second sensor includes a detection plate linked to the folding frame and circuit contacts driven by it. A microcontroller is electrically connected to the first sensor, the second sensor, and the winding assembly, and the microcontroller is configured to: when only the first sensor signal is received, operate in a normal leveling mode, in which the first sensor signal is processed based on a proportional-integral-derivative (PID) control algorithm to generate a continuous control signal to drive the winding assembly to perform servo leveling; when the second sensor signal is received, switch from the normal leveling mode to an emergency protection mode, in which the PID control algorithm is suspended and a preset emergency protection procedure is executed to forcibly drive the winding 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 drive module, which is disposed between the microcontroller and the electric reel, and is used to receive the pulse width modulation signal output by the microcontroller to realize continuous speed and direction control of the electric reel.

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

[0011] Furthermore, the microcontroller is configured to apply a control dead zone in the normal leveling mode, and not drive the take-up 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 based on driving speed data from an external speed sensor or GPS module.

[0013] Furthermore, the device also includes a windproof locking assembly, which comprises: a threaded groove on a fixed rod; a turbine blade threadedly connected to the threaded groove; the turbine blade rotating under wind force and moving axially along the threaded groove; a drive plate linked to the turbine blade; a limiting rod driven by the drive plate; and a locking block at the end of the limiting rod; and locking holes respectively formed on the mounting frame and the folding frame for engaging with the locking block; wherein, when the turbine blade moves under wind force, the drive plate expands the limiting rod, causing the locking block to engage in the locking 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 normal leveling mode, the microcontroller also performs calculations based on the height data measured by the sensor to achieve ground-following height control.

[0015] Furthermore, the second sensor also includes a limiting plate, a sliding rod fixedly connected to the limiting plate, a return spring sleeved on the sliding rod, and a limiting block with a circuit connector; the limiting plate overlaps the detection plate and can slide vertically within the groove, and the circuit contact is fixed to the end of the sliding rod; wherein, when the folding frame is tilted, the detection plate pushes the limiting plate upward, causing 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 return spring is used to provide a restoring force when the folding frame returns to horizontal.

[0016] This invention also provides a control method for active leveling of an air curtain type spray bar sprayer, applied to the aforementioned device, comprising the following steps: S1: Operate the device in the normal leveling mode, in which: The real-time tilt angle of the folding frame is continuously acquired through the first sensor; Based on the PID control algorithm and the real-time tilt angle, continuous leveling commands are calculated. The winding assembly is controlled according to the leveling command to perform servo leveling on the folding frame; S2: Continuously monitor the 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 leveling of the folding frame until the second sensor signal disappears.

[0017] Beneficial Effects: Compared with existing technologies, the advantages of this invention are as follows: This invention adopts an electronic servo leveling module, with a high-frequency sampling attitude sensor and PID control algorithm as its core. The integral term in the PID algorithm can continuously accumulate the small static error caused by the gravitational torque and generate a continuous compensating torque, thereby perfectly offsetting the natural drooping of the spraying rod and enabling it to maintain an absolutely horizontal position for a long time. The proportional and derivative terms in the PID algorithm can respond quickly and smoothly to high-frequency dynamic disturbances such as ground bumps. The proportional term ensures that the correction force is proportional to the tilt amplitude, while the derivative term can predict the trend of change and "brake" in advance, effectively suppressing overshoot and oscillation. Compared with the "on / off" control in existing technologies, this invention can precisely control the attitude error of the spraying rod within a very small range (such as ±0.5°), ensuring a high degree of consistency in the distance between the spraying rod and the crop canopy, fundamentally solving the problem of uneven pesticide distribution caused by tilting, and significantly improving the plant protection effect.

[0018] This invention employs a dual redundancy 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 equipment from going out of control and being damaged, greatly improving the reliability of the system in complex agricultural environments. This invention can automatically determine the working conditions and seamlessly switch between two modes: normal leveling and extreme protection. This ensures both the precision of daily operations and the rapid and reliable response in extreme situations.

[0019] This invention makes full use of the mechanical structure of the original equipment, with low modification costs, and provides an economical and efficient technical path for the intelligent upgrading of existing equipment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the tilting of the folding frame of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic diagram of the left-side structure of the folding frame of the present invention; Figure 4 This is a schematic diagram of the right side of the folding frame structure of the present invention; Figure 5 This is a schematic diagram of the turbine blade position structure of the present invention; Figure 6 This is a half-section front view of the rotating plate at the lower end of the present invention. Figure 7 This is a half-section diagram of the rotating plate at the lower end of the present invention; Figure 8 This is a half-sectional schematic diagram of the overall winding reel of the present invention; Figure 9 This is a schematic diagram of the overall bottom view of the present invention; Figure 10 for Figure 9 Enlarged schematic diagram of the structure at point A in the middle Figure 11 This is a top view of the folding frame of the present invention being blown by the wind; Figure 12 This is a schematic diagram illustrating the motion principle of the limiting 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 This is a flowchart of the active leveling control method of the present invention.

[0023] The attached diagram is labeled as follows: 1. Sprayer; 2. Spraying rod; 3. Fan; 4. Air guide shroud; 5. Mounting frame; 6. Folding frame; 7. Rotating plate one; 8. Rotating plate two; 9. Fixing rod; 10. Limiting rod; 11. Detection plate; 12. Limiting plate; 13. Sliding rod; 14. Limiting block; 15. Return spring; 16. Circuit contact; 17. Winding reel; 18. Electric reel; 19. Traction rope; 20. Threaded groove; 21. Turbine blade; 22. Drive plate; 23. Limiting rod; 24. Locking block; 25. Locking hole. Detailed Implementation

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

[0025] Example 1: Refer to Figures 1 to 12 This embodiment demonstrates the main mechanical structure of the active leveling device of an air curtain-type sprayer, including a sprayer body 1, on which a foldable folding frame 6 (set as a pair symmetrically arranged on the left and right sides) is connected via a mounting frame 5 and a rotating assembly. The folding frame 6 is used to support and unfold the long-arm spraying boom 2 and the air guide shroud 4. A winding assembly is provided at the upper end of the mounting frame 5, which includes a winding wheel 17 and an electric reel 18 at its shaft. One or more traction ropes 19 are fixed at one end to the outer end of the folding frame 6, and the other end is wound around the electric reel 18. By driving the electric reel 18 to rotate forward and backward, the traction ropes 19 are wound up and down, thereby precisely adjusting the pitch attitude of the folding frame 6 around its connection with the mounting frame 5.

[0026] Reference Figures 2 to 5 The rotating assembly allows the folding frame 6 to rotate relative to the mounting frame 5, enabling the unfolding and retraction of the spray bar and allowing a certain range of pitch adjustment during operation. Specifically, such as... Figure 2 and Figure 3 As shown, rotating plates 7 can be fixedly connected to the upper and lower ends of the mounting frame 5, and a fixing rod 9 is provided between the two opposing rotating plates 7. The two ends of the fixing rod 9 are connected to the folding frame 6 via rotating plates 8, or the folding frame 6 is directly fixed to the rotating plates 8, and the rotating plates 8 can rotate around the fixing rod 9. In some embodiments, the fixing rod 9 itself can be designed as an electric rotating shaft, driven to rotate by an external switch or controller, thereby causing the folding frame 6 to unfold from a folded state parallel to the travel direction of the sprayer 1 (for easy transport) to a working state perpendicular to the travel direction (e.g., ...). Figure 9 (As shown).

[0027] Reference Figure 2 , Figure 3 , Figure 4 and Figure 8The winding assembly is the actuator for leveling. A winding wheel 17 is located at the upper end of the mounting frame 5, and an electric winding shaft 18 is located at the pivot of the winding wheel 17. 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 winding shaft 18. Figure 1 As shown, when the folding frame 6 tilts (dashed line position), it can be pulled back to the horizontal position (solid line position) by controlling the electric roller 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, including a detection plate 11 linked to the rotating plate 8 of the folding frame 6. The detection plate 11 rotates clockwise around the limiting rod 10. When the folding frame 6 tilts, it presses the detection plate 11 downwards. Above the detection plate 11, a limiting plate 12 that can slide vertically in a groove is attached. A sliding rod 13 is fixedly connected to the limiting plate 12, and a reset spring 15 for providing reset force is sleeved on it. A circuit contact 16 is fixed to the end of the sliding rod 13, and the circuit contact 16 is connected to the circuit connector in the limiting block 14. When the tilt angle of the folding frame 6 exceeds a preset safety threshold, the detection plate 11 pushes the limiting plate 12 upwards, causing the sliding rod 13 and the circuit contact 16 to move upwards, eventually contacting the circuit connector to form a closed switch signal. This signal is sent to the microcontroller 27 as the second sensing signal.

[0029] The core of this invention lies in its dual-sensor, dual-mode control system architecture, the overall block diagram of which is shown below. Figure 13 As shown, the system includes a first sensor 26, a second sensor, a microcontroller 27, and a motor drive module 28. The microcontroller 27 uses an STM32F103 microprocessor and communicates with the first sensor 26 via I2C or SPI bus at high speed, and receives switching signals from the second sensor. The H-bridge motor drive module 28 acts as a bridge between the microcontroller 27 and the electric reel 18. It uses a BTS7960 to receive PWM control signals from the microcontroller 27 and convert them into a large current sufficient to drive the electric 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 measure the attitude of the mounting frame 5 in real time and accurately, thereby indirectly or directly obtaining the roll angle, i.e., the tilt angle, of the folding frame 6 relative to the direction of gravity. In each control cycle, the microcontroller executes the following steps: Read the axial angular velocity data of the gyroscope along the direction of travel of the sprayer. The final tilt angle calculated based on the previous cycle By integrating the angular velocity, the tilt angle of the current period can be predicted. : ; Read the gravity component data from the accelerometer on the vertical and lateral axes, and calculate the absolute tilt angle determined by the gravitational field at the current moment using the arctangent function. This step can provide an absolute angle reference without long-term drift, but it is susceptible to interference from the linear acceleration of the vehicle (such as bumps, acceleration and deceleration) and generates high-frequency noise. The results from the two steps above are weighted and fused to calculate the final, accurate, and stable tilt angle for the current cycle. : In this way, the fusion algorithm constitutes a digital filter: its high-pass filtering part (composed of weights) The dominant feature is the trust in the short-term, high-frequency dynamic response of the gyroscope, which effectively suppresses the instantaneous noise of the accelerometer; its low-pass filter section (composed of weights) The dominant method relies on the long-term, low-frequency stability of the accelerometer to continuously correct the integral drift of the gyroscope; it provides a high-precision tilt angle input with both fast response capability and long-term stability for the subsequent PID controller, which is the key technical link to achieve the high-precision, high-smoothness leveling control of this invention.

[0031] Example 2: Please refer to Figure 5 , Figure 10 and Figure 12 The device may also include a completely independent, passive windproof locking component. Figure 5 The structure of the turbine blade 21 in this assembly is shown, including a threaded groove 20 on the fixing rod 9, a turbine blade 21 threadedly connected to the groove, a drive vane 22 linked to the turbine blade 21, and a limiting rod 23 driven by the drive vane 22. A locking block 24 is provided at the end of the limiting rod 23. Corresponding locking holes 25 are provided on the mounting bracket 5 and the folding bracket 6. Figure 11 As shown, when encountering strong winds (arrows indicate wind direction), the airflow drives the turbine blade 21 to rotate and move upward along the threaded groove 20, thereby opening the two limit rods 23 via the drive plate 22. Figure 12 As shown, the locking block 24 on the limiting rod 23 will engage with the locking holes 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 away by strong winds. This process is completely mechanized and requires no 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 Embodiment 1, and the specific process is as follows: Step S101: System initialization.

[0034] After the device is powered on, the microcontroller 27 executes the initialization program. At this time, refer to Figure 2 As shown in the diagram, the operator needs to park the sprayer 1 on a level surface and trigger a "zero-point calibration" operation. The microcontroller 27 uses the attitude data read from the first sensor 26 at this time as the reference zero point, i.e., the target horizontal angle.

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

[0036] During normal operation, the system continues to operate in normal balancing mode as long as no extreme trigger signal is detected from the second sensor. In this mode, the microcontroller 27 cyclically executes the following servo control logic at a frequency of 100Hz: Data Acquisition and Precise Calculation: The microcontroller 27 reads the attitude data from the first sensor 26 in real time. To obtain a precise tilt angle, the program uses a complementary filtering algorithm to fuse the data from the accelerometer and gyroscope. To obtain a precise tilt angle that can both quickly respond to instantaneous changes and resist long-term drift, the program uses either a complementary filtering algorithm or a Kalman filtering algorithm to fuse and calculate these two sets of data.

[0037] PID Closed-Loop Calculation: The program compares the calculated real-time tilt angle with the target horizontal angle set in step S101 to calculate 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 preset proportional coefficients (Kp), integral coefficients (Ki), and derivative coefficients (Kd). These PID parameters can be preset or adjusted in real time according to different operational requirements (such as plot flatness and driving speed).

[0038] Dead-zone control and PWM generation: To avoid unnecessary minor adjustments and energy consumption when approaching a horizontal position, a control dead zone is set in the program. When the angle error is less than a preset small threshold (e.g., ±0.5°), the PID output is forced to zero; otherwise, the PID output is converted into a PWM signal with the corresponding duty cycle and polarity.

[0039] Drive execution: The PWM signal is sent to the motor drive module 28, driving the electric roller 18 to rotate, smoothly adjusting the posture of the folding frame 6 via the traction rope 19. This process occurs dynamically, such as... Figure 1As shown, the potentially tilted folding frame 6 (dashed line position) is continuously corrected back to the horizontal position (solid line position).

[0040] Step S103: Continuous monitoring of the extreme state.

[0041] In the main program loop, the microcontroller 27 continuously monitors the signal from the second sensor. The mechanical structure of the second sensor is as follows: Figure 5 , Figure 6 As shown, its triggering principle is that when the folding frame 6 is tilted too much, the detection plate 11 is lifted up, which eventually causes the circuit contact 16 to close.

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

[0043] When the sprayer experiences a bump, causing the tilt angle of the folding frame 6 to exceed a preset safety threshold (e.g., ±10°), the mechanical mechanism of the second sensor is triggered, and the system immediately switches from the normal leveling mode to the emergency protection mode. In this mode, the microcontroller 27 suspends PID calculations and instead executes a preset emergency protection program, such as driving the electric roller 18 with a fixed, high power to force a reset.

[0044] Once the microcontroller 27 detects this signal, it immediately switches the system from the normal balancing mode to the emergency protection mode. In this mode, the program suspends PID calculations and instead executes a preset, simple, and reliable emergency protection program. This program instructs the motor drive module 28 to drive the electric reel 18 in the opposite direction of the tilt at a preset fixed power (e.g., 50% duty cycle) to perform a powerful and rapid reset operation.

[0045] Step S106: Automatic recovery.

[0046] When the folding frame 6 is pulled back within the safety threshold under the emergency protection procedure, refer to Figure 12 The schematic diagram of the limit rod's movement principle shows that when the mechanical mechanism of the second sensor resets, the circuit contact 16 disconnects, and the second sensor signal disappears. After detecting this state, the microcontroller 27 stops the emergency protection program and automatically switches the system back to the normal leveling mode (step S102), restoring high-precision servo leveling control.

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

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

Claims

1. An active leveling device for an air curtain type spray bar sprayer, comprising a mounting frame (5), a folding frame (6) rotatable around the mounting frame (5) to achieve leveling, and a rewind assembly for driving the folding frame (6) to rotate; characterized in that, The device further includes: The first sensor (26) is used to detect the tilt angle of the folding frame (6) in real time to generate a first sensing signal; The second sensor is used to generate a second sensing signal by mechanical triggering when the tilt angle of the folding frame (6) exceeds a preset safety threshold. The second sensor includes a detection plate (11) linked with the folding frame (6) and a circuit contact (16) driven by it. The microcontroller (27) is electrically connected to the first sensor (26), the second sensor, and the winding assembly. The microcontroller (27) is configured to: when only the first sensor signal is received, operate in a normal 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 winding assembly to perform servo leveling; when the second sensor signal is received, switch from the normal 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 winding assembly to restore the folding frame (6) to within the preset safety threshold.

2. The active leveling device for the air curtain type 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 the accelerometer and gyroscope data in the inertial measurement unit to calculate the tilt angle.

3. The active leveling device for the air curtain type sprayer according to claim 1, characterized in that, The device also includes an H-bridge motor drive module (28), which is located between the microcontroller (27) and the electric reel (18) and is used to receive the pulse width modulation signal output by the microcontroller (27) to realize continuous speed and direction control of the electric reel (18).

4. The active leveling device for the air curtain type sprayer according to claim 3, characterized in that, The emergency protection procedure includes driving the electric reel (18) at a preset fixed power.

5. The active leveling device for the air curtain type sprayer according to claim 1, characterized in that, The microcontroller (27) is configured to apply a control dead zone in the normal leveling mode, and not drive the take-up 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 type 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 based on driving speed data from an external speed sensor or GPS module.

7. The active leveling device for the air curtain type sprayer according to claim 1, characterized in that, The device also includes a windproof locking assembly, which includes: a threaded groove (20) on the fixed rod (9), a turbine blade (21) threadedly connected in the threaded groove (20), the turbine blade (21) rotating under wind force and moving axially along the threaded groove (20), a drive plate (22) linked with the turbine blade (21), a limiting rod (23) driven by the drive plate (22), and a locking block (24) at the end of the limiting rod (23); and locking holes (25) respectively opened on the mounting frame (5) and the folding frame (6) for engaging with the locking block (24). When the turbine blade (21) moves under the action of wind, the driving plate (22) opens the limiting rod (23), so that the locking block (24) is locked into the locking hole (25) to achieve physical locking of the mounting frame (5) and the folding frame (6).

8. The active leveling device for the air curtain type sprayer according to claim 1, characterized in that, The device also includes at least one ultrasonic or lidar sensor fixed to the end of the folding frame (6). In the normal leveling mode, the microcontroller (27) also performs calculations based on the height data measured by the sensor to achieve ground-following height control.

9. The active leveling device for the air curtain type sprayer according to claim 1, characterized in that, The second sensor also includes a limiting plate (12), a sliding rod (13) fixedly connected to the limiting plate (12), a reset spring (15) sleeved on the sliding rod (13), and a limiting block (14) provided with a circuit connector; the limiting plate (12) overlaps the detection plate (11) and can slide vertically in the 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 limiting plate (12) upward, causing the sliding rod (13) and the circuit contact (16) to move, so that the circuit contact (16) contacts the circuit connector to generate the second sensing signal. 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 type spray bar sprayer, applied to the device described in claim 1, characterized in that, Includes the following steps: S1: Operate the device in normal leveling mode, in which: The real-time tilt angle of the folding frame (6) is continuously acquired by the first sensor (26); Based on the PID control algorithm and the real-time tilt angle, continuous leveling commands are calculated. The winding assembly is controlled according to the leveling command to perform servo leveling on the folding frame (6); S2: Continuously monitor the second sensing signal generated by the second sensor; S3: When the second sensing 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 leveling of the folding frame (6) until the second sensing signal disappears.

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