Spraying unmanned aerial vehicle and working method thereof

Abstract

The invention provides a spraying unmanned aerial vehicle and a working method thereof. The spraying unmanned aerial vehicle comprises an unmanned aerial vehicle body. The spraying assembly is used for atomizing and spraying paint; the sensor assembly faces the spraying direction of the spraying assembly and is used for measuring the distance and monitoring the spraying state; the air curtain protection assembly comprises two first nozzles arranged on the two sides of the sensor assembly and a first air source connected with the first nozzles, the first nozzles are strip-shaped and obliquely face the detection area of the sensor assembly, two symmetrical thin-layer air curtains can be formed, and the front ends of the two thin-layer air curtains are converged to form an air curtain barrier; the outer layer of the air curtain barrier can restrain fog drop diffusion, control the fog beam range and reduce surrounding air disturbance; the inner layer of the air curtain barrier is tightly attached to the front portion of the sensor assembly to form a local positive pressure barrier, and fog drops are prevented from making contact with the sensor assembly. According to the spraying unmanned aerial vehicle, the structure is compact, the integration degree is high, efficient protection can be formed for the sensor assembly, and reliable guarantee is provided for continuous and stable operation of spraying operation.

Description

Technical Field

[0001] This invention relates to a drone, and more particularly to a spraying drone and its operating method. Background Technology

[0002] With the rapid development of drone technology, its application in industrial spraying, building decoration, and wall coating is becoming increasingly widespread. Especially in high-precision wall spraying operations, drones demonstrate significant advantages due to their maneuverability, programmable operation, and remote control capabilities. Using drone platforms to perform wall spraying operations enables efficient spraying and uniform coating in complex wall environments, while reducing manual labor intensity and improving construction efficiency and quality.

[0003] However, wall painting drones still face challenges from various complex environmental factors in actual operations, including high-atomization spraying conditions, airflow disturbances, variations in spraying distance, and paint rebound particles. These factors can affect the drone's flight stability, spraying accuracy, and sensor functionality. For example, a high-atomization spraying environment can cause paint particles to adhere to the drone's sensor surface, reducing the ranging and imaging performance of LiDAR or cameras; strong winds or airflow disturbances can affect the stability of the drone's hovering attitude and spraying trajectory; paint rebound and suspended particles during spraying can contaminate sensors, thereby affecting the drone's autonomous navigation and closed-loop spraying control.

[0004] These complex environmental conditions present several technical challenges to the UAV system. First, sensors must operate stably in high-atomization and high-particle environments to ensure that lidar and cameras can acquire real-time information on spraying position and distance, enabling closed-loop control of the spraying process. Second, airflow disturbances and sprayed particles require the UAV platform to achieve high-precision hovering, stable navigation, and safe spraying within limited weight and power constraints. Simultaneously, the system structure needs to be splash-proof, corrosion-resistant, easy to clean, and convenient to maintain, adapting to long-term continuous operation and maintaining reliability under varying construction conditions.

[0005] Current technologies for wall painting drones still have shortcomings in terms of sensor protection and adaptability to painting environments. For example, in high-atomization painting environments, the sensors of some drone systems are easily contaminated, leading to a decrease in ranging and imaging accuracy; some protective structures are complex and heavy, limiting the drone's maneuverability and endurance; existing painting strategies struggle to simultaneously achieve air curtain protection, painting accuracy, and operational efficiency. These technological bottlenecks limit the application and reliability of drones in high-precision wall painting operations.

[0006] With the development of building automation and intelligent industrial construction, higher demands are being placed on the precision, reliability, and continuous operation capabilities of drone spraying. The market demand for wall spraying drones with high protection, high precision, and low maintenance requirements continues to grow. Developing a drone spraying technology solution that can ensure the normal operation of lidar and cameras in high-atomization spraying environments and effectively block paint droplets through air curtains or protective structures has significant practical implications and application value. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a spraying drone and its working method that is compact in structure, requires little installation space, can continuously and effectively block paint droplets and protect sensors during the spraying process, and ensure the stability and accuracy of the spraying process.

[0008] This invention provides a spray painting drone, comprising: Drone body 1; The spraying component 2 is installed on the main body 1 of the drone and is used for atomized spraying of paint; Sensor assembly 4 is mounted on the main body of the UAV 1 and faces the spraying direction of the spraying assembly 2, and is used for distance measurement and monitoring of the spraying status; The air curtain protection component 3 is installed on the main body of the UAV 1. It includes two first nozzles 31 disposed on both sides of the sensor component 4 and a first air source 36 connected to the first nozzles 31. The first nozzles 31 are strip-shaped and tilted towards the detection area of ​​the sensor component 4, and can form two symmetrical thin air curtains. The front ends of the two thin air curtains merge to form an air curtain barrier. The outer layer of the air curtain barrier can constrain the diffusion of fog droplets, control the range of fog beams, and reduce surrounding air disturbance. The inner layer of the air curtain barrier is in close contact with the front of the sensor assembly 4, forming a local positive pressure barrier and preventing droplets from contacting the sensor assembly 4.

[0009] Furthermore, the sensor assembly 4 includes an image acquisition unit and a distance sensing unit. The distance sensing unit is used to sense the distance between the UAV body 1 and the spraying carrier, and the image acquisition unit is used to capture image information of the spraying surface in real time.

[0010] Furthermore, the distance sensing unit is a lidar, and the image acquisition unit is a camera.

[0011] Furthermore, the first air source is a turbine fan.

[0012] Furthermore, the air curtain protection assembly 3 also includes a distributor 37 disposed at the air outlet end of the first air source 36. The distributor 37 has two air outlet ends and is used to divide the airflow into two paths and connect them to the two first nozzles 31 respectively.

[0013] Furthermore, the air curtain protection assembly 3 also includes a mounting bracket 33, with two first nozzles 31 symmetrically arranged on both sides of the mounting bracket 33 to form a front-open anti-splash mounting area 30, and the sensor assembly 4 installed in the anti-splash mounting area 30.

[0014] Furthermore, a transparent protective cover is detachably installed at the front open end of the splash-proof installation area 30.

[0015] Furthermore, the angle between the air outlet direction of the first nozzle 31 and the axis of the sensor assembly 4 is 35°-45°.

[0016] Furthermore, the angle between the air outlet direction of the first nozzle 31 and the axis of the sensor assembly 4 is 40°.

[0017] Furthermore, the outlet length of the first nozzle 31 is 5mm-20mm.

[0018] Furthermore, the outlet length of the first nozzle 31 is 15 mm.

[0019] Furthermore, the air curtain protection component 3 also includes a strip-shaped second nozzle 32 and a second air source 34 connected to the second nozzle 32. The second nozzle 32 is horizontally arranged above the sensor component 4 and tilted upwards to provide supplementary protection against the intrusion of mist droplets above the sensor component 4.

[0020] Furthermore, the angle between the air outlet direction of the second nozzle 32 and the horizontal plane is 5°-10°.

[0021] Furthermore, the angle between the air outlet direction of the second nozzle 32 and the horizontal plane is 7.5°.

[0022] Furthermore, the second air source 34 is a turbine fan.

[0023] Furthermore, the first nozzle 31 has a first air inlet chamber, the air outlet of the first air inlet chamber extends outward and narrows to form a first transition chamber, the air outlet of the first transition chamber extends outward to form a first compression chamber, and the air outlet of the first compression chamber is provided with a first slit nozzle 3130.

[0024] Furthermore, the first nozzle 31 includes a first tube 311, in which the first air inlet chamber is formed. One end of the first tube 311 serves as an air inlet and is connected to the first air source 36. The sidewall of the first tube 311 has a first opening along its length. The two sides of the first opening extend outward to form a first transition section 312. The distance between the two first transition sections 312 gradually decreases in the air outlet direction and forms the first transition cavity. The first transition section 312 extends outward to form a first compression section 313. The two first compression sections 313 form the first compression cavity. The end of the first compression cavity has a plurality of strip-shaped outlets along its length and forms the first slit nozzle 3130.

[0025] Furthermore, the second nozzle 32 has the same structure as the first nozzle.

[0026] Meanwhile, the present invention also provides a method for operating a spraying drone, which includes the following steps: S1. The main body of the drone approaches the target surface and completes precise positioning through lidar and camera, hovering at a predetermined position in front of the target wall or component; At this time, the air curtain protection component 3 is in a low-flow standby state to ensure that the surface of the sensor component is not affected by the initial environment's trace paint mist droplets; S2. The air curtain protection component automatically switches to high flow mode to form a multi-layer air curtain and constitute an air curtain barrier. Among them, the outer layer of the air curtain barrier constrains the diffusion of sprayed droplets, controls the range of the mist beam, and reduces the disturbance of the surrounding air. The inner layer of the air curtain barrier is placed close to the front of the lidar and camera, forming a local positive pressure barrier to prevent fog droplets from contacting the sensors. S3. Spraying component 2 starts and begins spraying paint. The laser radar monitors the spray distance in real time to keep the nozzle at the optimal incident angle and distance from the wall, reducing the rebound splash caused by droplet impact from the source and improving the uniformity of spraying. During this process, the spray droplets are effectively shaped under the action of the air curtain barrier, making the spraying effect controllable. At the same time, a stable pressure difference is maintained around the sensor assembly, preventing paint droplets from approaching the sensor assembly. S4. After the spraying operation is completed, the spraying component 2 stops the paint output, and the air curtain protection component reduces the power to low and enters standby mode. S5. The system is ready to execute the next spraying task, or move to the next work position according to the preset path, or return to base.

[0027] Furthermore, when the sensor components are accidentally contaminated or malfunction, the spraying operation is suspended and the components are moved back to a safe distance. At the same time, the air curtain protection components automatically switch to high flow mode and perform continuous blowing and cleaning. If the sensor components return to normal, the painting operation will continue. If the sensor components fail to recover, the painting operation will end and the machine will automatically return to base.

[0028] This invention relates to a painting drone that utilizes two continuously rotating turbines to provide a stable airflow to the nozzles. The generated airflow is guided by an internal flow-guiding structure and then evenly sprayed out from the nozzle outlet, forming a continuous and stable air curtain protective layer in front of the device. This air curtain establishes a positive pressure environment within the target protection area, blocking paint droplets and suspended particles generated during the painting process and preventing them from intruding into the field of view of the protected components, thus achieving effective splash protection for the sensors. In high-atomization painting environments, it provides continuous, stable, and uniform splash protection to the critical field of view areas of the lidar and camera, effectively inhibiting the adhesion and deposition of paint droplets and environmental suspended particles on the sensor surface. This ensures that the sensor components maintain good imaging clarity and ranging stability throughout the painting process, significantly improving the safety, system stability, and painting accuracy of the painting drone during autonomous operation. This invention's painting drone features a compact structure and high integration, providing efficient protection for sensor components and reliable assurance for continuous and stable painting operations. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the spraying drone of the present invention; Figure 2 This is a schematic diagram of the air curtain protection component of the spraying drone of the present invention; Figure 3 This is a schematic diagram of the exploded structure of the air curtain protection component of the spraying drone of the present invention; Figure 4 This is a schematic diagram of the structure of the first nozzle and the second nozzle of the spraying drone of the present invention; Figure 5 This is a cross-sectional view of the first nozzle of the spraying drone of the present invention; Figure 6 This is a cross-sectional view of the second nozzle of the spraying drone of the present invention; Figure 7 This is a schematic diagram of the workflow of the spraying drone of the present invention.

[0030] In the diagram: 1. UAV body, 2. Spraying assembly, 3. Air curtain protection assembly, 30. Anti-splash installation area, 31. First nozzle, 311. First pipe body, 312. First transition section, 313. First compression section, 3130. First slit nozzle, 32. Second nozzle, 321. Second pipe body, 322. Second transition section, 323. Second compression section, 3230. Second slit nozzle, 33. Mounting bracket, 331. Horizontal partition, 34. Second air source, 35. Second hose, 36. First air source, 37. Distributor, 38. First hose, 4. Sensor assembly, 41. Distance sensing unit, 42. Image acquisition unit. Detailed Implementation

[0031] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] See Figures 1-6 The present invention provides a spraying drone, including a drone body 1, a spraying component 2 and an air curtain protection component 3.

[0033] The spraying component 2 is installed on the main body 1 of the drone and is used for atomized spraying of paint; the sensor component 4 is installed on the main body 1 of the drone and its detection direction is towards the spraying direction of the spraying component 2, and is used for distance measurement and monitoring of the spraying status.

[0034] The air curtain protection component 3 is installed on the main body 1 of the drone and includes a first nozzle 31 and a first air source 36 disposed on both sides of the sensor component 4. There are two first nozzles 31, and the first air source 36 is connected to the first nozzles 31 for supplying air. The first nozzle 31 is strip-shaped, and its air outlet is inclined toward the detection area of ​​the sensor component 4. Specifically, the air outlet of the first nozzle 31 is directed toward the detection direction of the sensor component 4 and is inclined inward, which can form two symmetrical thin air curtains. Due to the inclined arrangement of the first nozzle 31, the front ends of the thin air curtains on both sides merge to form an air curtain barrier. In this embodiment, the first air source 36 is a turbine fan, which is a micro turbine fan with small size and high flow rate, and can provide stable airflow to form a continuous air curtain.

[0035] The outer layer of the air curtain barrier can constrain the diffusion of fog droplets, control the range of fog beams, and reduce surrounding air disturbance; the inner layer of the air curtain barrier is close to the front of the sensor assembly 4, forming a local positive pressure barrier and preventing fog droplets from contacting the sensor assembly 4.

[0036] This application sets an air curtain protection component 3 on the outside of the sensor component 4, and forms a directional thin-layer air curtain by using symmetrically arranged strip-shaped air outlets. This not only effectively isolates the sensor component 4 from the contamination of paint mist during the spraying process, but also achieves active protection through a local positive pressure environment. This structure continuously maintains the surface cleanliness of the sensor component 4 during dynamic operation, ensuring the accuracy of distance measurement and monitoring, thereby improving the stability and reliability of the automated spraying of the whole machine, and providing key technical support for unmanned operation under complex working conditions.

[0037] The sensor component 4 in this application includes an image acquisition unit 42 and a distance sensing unit 41. The distance sensing unit 41 is used to sense the distance between the drone body 1 and the spraying carrier (such as a wall or component), and the image acquisition unit 42 is used to capture image information of the spraying surface in real time. Specifically, the distance sensing unit 41 is a lidar, and the image acquisition unit 42 is a camera. The lidar accurately measures the distance to ensure that the nozzle and the working surface (spraying surface) maintain a constant distance. At the same time, in conjunction with the camera, it can understand the spraying texture or color of the spraying area in real time, providing visual feedback support for spraying, thereby ensuring the accuracy and consistency of the spraying operation.

[0038] To achieve airflow balance and prevent the air curtains on both sides from deflecting due to uneven pressure, the air curtain protection component 3 in this application also includes a distributor 37. The distributor 37 is located at the outlet end of the first air source 36 and has one inlet end and two outlet ends, forming an "A" shape. The inlet end is connected to the outlet end of the first air source 36, and the two outlet ends are respectively connected to the first nozzles 31 on both sides through the first hose 38. It is used to divide the airflow output from the first air source 36 into two paths and deliver them to the two first nozzles 31 respectively. The distributor 37 ensures that the airflow output from the first air source is evenly distributed to the first nozzles 31 on both sides, maintaining consistent pressure on the left and right air curtains, avoiding protection failure due to airflow deviation, and ensuring the reliability and stability of the air curtain protection component 3.

[0039] To facilitate installation and layout, the air curtain protection component 3 in this application also includes a mounting bracket 33. Two first nozzles 31 are symmetrically arranged on both sides of the mounting bracket 33. Specifically, the first nozzles 31 are vertically arranged, that is, the two first nozzles 31 are parallel to each other, forming an open front anti-splash installation area 30. The sensor component 4 is installed in the anti-splash installation area 30 and faces forward. In this embodiment, a horizontal partition 331 is provided in the anti-splash installation area 30, which divides the anti-splash installation area 30 into an upper area and a lower area. The lidar and camera are installed in the upper area and the lower area, respectively. The layout of the sensor component 4 ensures that ranging and imaging do not interfere with each other, while being fully covered and protected by the air curtain. The horizontal partition 331 further enhances the structural rigidity. In this embodiment, a transparent protective cover is provided at the open front end of the anti-splash installation area 30. It is detachable for easy maintenance and replacement.

[0040] To achieve better protection and prevent the air curtain confluence point from being too far forward or too far backward, in this embodiment, the angle between the air outlet direction of the first nozzle 31 and the axis of the sensor assembly 4 is 35°-45°, that is, the air outlet direction of the first nozzle 31 is forward and deflected inward by 35°-45°, preferably 40°; at the same time, the outlet length of the first nozzle 31 is 5mm-20mm, preferably 15mm, which can effectively control the confluence point of the air curtain and improve the protection effect.

[0041] To achieve better protection, the air curtain protection component 3 in this application further includes a second nozzle 32 and a second air source 34. The structure of the second nozzle 32 is the same as that of the first nozzle 31. Specifically, the second nozzle 32 is strip-shaped and is horizontally positioned above the sensor component 4, with its output end tilted upwards. The second air source 34 is connected to the second nozzle 32 through a second hose 35 to supply air to it. In this embodiment, the second air source 34 is a turbine fan. The second nozzle 32 is used to provide supplementary protection against the intrusion of mist droplets above the sensor component 4. In this application, the angle between the air outlet direction of the second nozzle 32 and the horizontal plane is 5°-10°, preferably 7.5°.

[0042] The structure of the first nozzle 31 in this application will be described below; The first nozzle 31 is generally strip-shaped and has a first air inlet chamber. The air outlet end of the first air inlet chamber extends outward (i.e., in the air outlet direction) and narrows to form a first transition chamber. The air outlet end of the first transition chamber extends outward (i.e., in the air outlet direction) to form a first compression chamber. The air outlet end of the first compression chamber is provided with a first slit nozzle 3130. Specifically, the first nozzle 31 includes a first tube 311. In this embodiment, the first tube 311 is vertically arranged, and a first air inlet chamber is formed inside the first tube 311. One end of the first tube 311 serves as the air inlet end and can be connected to the first air source 36. The other end of the first tube 311 is sealed. A first opening is provided on the side wall of the first tube 311. The first opening is strip-shaped and parallel to the length direction of the first tube 311. The first opening is forward-facing and tilted inward at a certain angle, i.e., slightly tilted towards the other first nozzle 31. The two sides of the first opening extend outward, i.e., in the air outlet direction, to form a first transition chamber. The distance between the two first transition sections 312 gradually decreases in the direction of air outlet, forming a first transition cavity. That is, the first transition cavity has a structure with a large air inlet and a small air outlet. The first transition section 312 extends outward, that is, it extends in the direction of air outlet, forming a first compression section 313. In this embodiment, the two first compression sections 313 are parallel to each other, and a first compression cavity is formed between the two first compression sections 313. The end of the first compression cavity has multiple strip-shaped outlets along the length direction, forming a first slit nozzle 3130, which can accommodate gas to form a thin air curtain at high speed, effectively blocking the intrusion of external particles and droplets. Specifically, there are multiple baffles in the first compression cavity, which are equidistantly arranged along the length direction of the first compression cavity to form multiple strip-shaped first air ducts. The ends of the first air ducts are open, forming multiple first slit nozzles 3130. The length of the first air duct is the outlet length, which is 5mm-20mm, preferably 15mm.

[0043] The second nozzle 32 has the same structure as the first nozzle 31. Specifically, the second nozzle 32 is generally strip-shaped, horizontally arranged, and its outlet end is located at the rear end of the first nozzle 31. The outlet direction is forward and tilted upward at a certain angle. The second nozzle 32 has a second air inlet chamber. The outlet end of the second air inlet chamber extends outward (i.e., in the outward direction) and narrows to form a second transition chamber. The outlet end of the second transition chamber extends outward (i.e., in the outward direction) to form a second compression chamber. The outlet end of the second compression chamber is provided with a second slit nozzle 3230. Specifically, the second nozzle 32 includes a second tube 321. In this embodiment, the second tube 321 is horizontally arranged, and a second air inlet chamber is formed within the second tube 321. One end of the second tube 321 serves as the air inlet end and is connected to the second air source 34. The other end of the second tube 321 is sealed. A section is formed on the side wall of the second tube 321. There is a second opening, which is strip-shaped and parallel to the length direction of the second tube 321. The second opening is forward-facing and tilted upward at a certain angle. The two sides of the second opening extend outward, that is, extend in the direction of air outlet, to form a second transition section 322. The distance between the two second transition sections 322 gradually decreases in the direction of air outlet, forming a second transition cavity. That is, the second transition cavity has a structure with a large air inlet end and a small air outlet end. The ends of the second transition sections 322 extend outward, that is, extend in the direction of air outlet, to form a second compression section 323. In this embodiment, the two second compression sections 323 are parallel to each other, and a second compression cavity is formed between the two second compression sections 323. The ends of the second compression cavity have multiple strip-shaped outlets along the length direction to form a second slit nozzle 3230, which can accommodate gas to form a thin air curtain at high speed, effectively blocking the intrusion of external particles and droplets. Specifically, a partition is also provided in the second compression chamber. There are multiple partitions, which are equidistantly arranged along the length of the second compression chamber to form multiple strip-shaped second air ducts. The ends of the second air ducts are open to form multiple second slit nozzles 3230. The length of the second air duct is the outlet length, which is 5mm-20mm, preferably 15mm.

[0044] In addition, the present invention also provides a method for operating a spraying drone, see below. Figure 7 It includes the following steps: S1. The main body of the drone approaches the target surface and completes precise positioning through lidar and camera, hovering at a predetermined position in front of the target wall or component; At this time, the air curtain protection component 3 is in a low-flow standby state to ensure that the surface of the sensor component is not affected by the initial environment's trace paint mist droplets; S2. The air curtain protection component automatically switches to high flow mode to form a multi-layer air curtain and constitute an air curtain barrier. Among them, the outer layer of the air curtain barrier constrains the diffusion of sprayed droplets, controls the range of the mist beam, and reduces the disturbance of the surrounding air. The inner layer of the air curtain barrier is placed close to the front of the lidar and camera, forming a local positive pressure barrier to prevent fog droplets from contacting the sensors. S3. Spraying component 2 starts and begins spraying paint. The laser radar monitors the spray distance in real time to keep the nozzle at the optimal incident angle and distance from the wall, reducing the rebound splash caused by droplet impact from the source and improving the uniformity of spraying. During this process, the spray droplets are effectively shaped under the action of the air curtain barrier: the mist is more concentrated and the spray dispersion angle is reduced; large droplets are dispersed by secondary reshaping of the airflow; the probability of droplets flying towards the sensor is greatly reduced; in this way, the spraying effect is controllable, while the lidar and camera are effectively protected.

[0045] The spray droplets are effectively shaped under the action of the air curtain barrier, making the spraying effect controllable. At the same time, a stable pressure difference is maintained around the sensor component, preventing paint droplets from approaching the sensor component. Even with long-term continuous spraying, no oil film or obstruction will form on the sensor surface, ensuring clear imaging and reliable distance measurement.

[0046] S4. After the spraying operation is completed, the spraying component 2 stops the paint output, and the air curtain protection component reduces the power to low and enters standby mode. S5. The system is ready to execute the next spraying task, or move to the next work position according to the preset path, or return to base. To ensure the safety and reliability of the spraying operation, when the sensor component is accidentally contaminated or malfunctions, the spraying operation is suspended and the component is moved back to a safe distance. At the same time, the air curtain protection component automatically switches to high flow mode and performs continuous purging and cleaning. If the sensor components return to normal, the painting operation will continue. If the sensor components fail to return to normal, the spraying operation will be terminated and the system will automatically return to base to clean the sensors before resuming operation, thereby ensuring the reliability of the sensors and the overall safety of the operation during the spraying process.

[0047] The following is a detailed explanation; This application's spraying drone is mainly used in scenarios such as wall spraying, component spraying, and fine spraying of narrow structural surfaces. It can effectively protect key sensors such as lidar and cameras from paint droplet contamination during the drone's spraying operation, thereby ensuring that the sensors have continuous, stable, and clear imaging capabilities and reliable positioning and ranging performance.

[0048] The painting drone mainly consists of the drone body 1, the painting component 2, the air curtain protection component 3, the sensor component 4, and the intelligent control module. The air curtain protection component 3 can spray a high-speed, directional thin layer of air curtain at its outlet, forming a continuous air barrier around the lidar and camera, blocking paint droplets from entering the sensor's field of view, reducing the risk of pollution at the source and improving operational stability.

[0049] The sensor components include a lidar and a camera, which are integrated and installed in a protective cavity (splash-proof installation area) at the front of the drone body. A transparent protective cover is set at the front of the protective cavity. The protective cover is made of a transparent material that is resistant to solvents and paint corrosion to reduce the impact of long-term spraying operations on the sensor's field of view transmittance. It adopts a detachable structure for easy replacement and maintenance.

[0050] LiDAR and cameras are used to acquire spatial pose information of the drone and the working wall, spraying distance, and spraying quality feedback. Their output signals are connected to the flight control system and air curtain control logic module to realize attitude control, spray distance adjustment, and air curtain start / stop and intensity adjustment during the spraying operation, thereby ensuring closed-loop control and operational safety of the spraying process.

[0051] The first and second air sources are micro turbine fans, with air intake filters installed at their inlet ends. These filters are located on the exterior of the UAV and powered by an independent power source. The air intake filters are installed at the inlet ends of each micro turbine fan to pre-filter the air entering the fan, effectively preventing dust, paint droplets, and other impurities from entering the fan. This reduces the risk of contamination to the fan impeller and bearings, and improves the operational stability and reliability of the micro turbine fans in the spraying environment.

[0052] The nozzles include a first nozzle and a second nozzle. The high-speed airflow output from the micro-turbine fan first enters the distributor, where it is evenly split into left and right airflows. These airflows are then delivered to the corresponding nozzle inlets via independent flexible hoses. The flexible air delivery hoses are made of bend-resistant and paint corrosion-resistant materials, and their wiring paths are optimized to avoid interference with the UAV's thrusters, vibration damping structures, or moving parts of the boom. Key connections in the system utilize quick-connect couplings for easy component replacement, maintenance, and on-site repair, thereby improving the reliability and maintainability of the entire splash protection system.

[0053] The nozzles, as key actuators for air curtain formation, are arranged in the area surrounding the front of the sensor assembly. Two first nozzles are positioned on the left and right sides of the sensor assembly, with an outlet angle of 40°. A second nozzle is positioned above the sensor assembly, with an outlet angle of 7.5° to the horizontal direction, serving as supplementary protection against vertical droplet intrusion.

[0054] The ends of the first and second nozzles adopt a slit-type or ring-type nozzle structure and integrate a flow guide structure inside to shape the airflow, making the ejected airflow thinner, faster, and more directional. The airflow ejected from the left and right first nozzles converges in front of the sensor assembly and together with the airflow from the upper second nozzle to form a continuous and stable three-dimensional air curtain barrier, thereby effectively blocking paint droplets from entering the field of view of the lidar and camera.

[0055] When performing close-range wall spraying operations, the first nozzle and the second nozzle play a key role in building a stable and continuous protective air curtain in front of the lidar and camera. They are the core components of the air curtain protection system to achieve effective splash prevention. The first nozzle and the second nozzle are connected to the output end of the micro turbine fan through a flexible air supply hose, and the air is evenly supplied to the left and right first nozzles through a distributor that splits the air flow into two paths to ensure that the airflow intensity at the outlet of each first nozzle is consistent.

[0056] During the spraying process, the high-speed airflow is shaped by the rectifying chamber inside the first or second nozzle and then ejected from the slit nozzle to form a sheet-like air curtain with a certain thickness and speed. The air curtains ejected from the first nozzles on the left and right sides converge in the space in front of the sensor assembly and work together with the airflow from the second nozzle on the upper side to form a positive pressure airflow barrier covering the entire field of view of the lidar and camera. This positive pressure barrier can effectively block paint droplets from the spraying nozzle, wall rebound particles, and suspended matter in the environment from entering the sensor protection area, thereby maintaining a clear field of view and stable ranging capability of the lidar and camera throughout the spraying process.

[0057] When the drone approaches the wall to perform spraying operations, the air curtain protection component is in continuous working condition and can automatically adjust the airflow intensity according to the spraying conditions to adapt to different spraying distances, attitude changes and external wind disturbance conditions. By reasonably controlling the air curtain intensity and coverage, the air curtain can not only reduce the probability of paint droplets gathering near the sensor, but also limit the disorderly diffusion of the spray mist to a certain extent, thereby improving the spraying accuracy and coating uniformity.

[0058] The following section verifies the air curtain performance of the nozzle.

[0059] (1) Experimental verification Experiment 1: The effect of different air curtain outlet lengths on the water mist suppression performance of sprayed coatings.

[0060] 1) Experimental Objective Under dual-nozzle spraying conditions, the effect of different air curtain outlet lengths (5 mm and 15 mm) on suppressing water mist adhesion during the spraying process was evaluated. By quantitatively measuring the residual water mass on the target surface, the actual performance difference of the air curtain in blocking droplet intrusion was verified, providing a basis for optimizing the air curtain structure parameters.

[0061] 2) Experimental Design and Testing Conditions The experiment included three sets of comparative operating conditions: Air curtain-free operating condition (baseline) Air curtain outlet length 5 mm (Option 1) Air curtain outlet length 15 mm (Option 2) Under the same spraying parameters, 5, 10, 15 and 20 spraying tests were conducted respectively (20 tests were not set for some working conditions). After the spraying was completed, the target surface was weighed and the residual water mass (g) was measured as a quantitative evaluation index of the degree of water mist intrusion.

[0062] 3) Summary of experimental data Table 1: Comparison of Residual Water Mass and Reduction Rate under Different Air Curtain Schemes

[0063] 4) Analysis of experimental results No air curtain conditions Without airflow isolation, sprayed water mist can directly enter the target area and adhere to the surface. The residual water mass accumulates significantly with the number of sprays. After 20 sprays, the residual water content reaches 1.80 g, indicating that there are almost no effective anti-fogging measures under this condition.

[0064] 5 mm air curtain solution This solution can form a relatively stable thin air curtain in front of the target area, which has a significant blocking effect on water mist. Within the range of 5–15 sprays, the residual water mass reduction rate remains between 87% and 95%, proving that the short-exit air curtain has a certain fog suppression capability under low to medium spray intensity.

[0065] 15 mm air curtain solution The resulting air curtain exhibits significantly enhanced thickness and stability, almost completely blocking water mist from entering the target area. The inhibition rate remains above 98% across all spraying cycles, with near 100% water mist isolation achieved in some conditions. Even under high spraying cycles, residual water levels remain extremely low.

[0066] Explanation of experimental limitations Since the air curtain is mainly designed to prevent lateral and forward water mist intrusion, it cannot completely block vertically falling droplets from above. Therefore, this experiment did not include a scenario where water was sprayed directly from above, in order to avoid interfering with the objective evaluation of the air curtain's fog suppression performance.

[0067] Experiment 2: Verification of the fog suppression performance of the air curtain under different droplet sizes.

[0068] 1) Experimental Objective Under the three-nozzle spraying condition, by arranging air curtains (with an outlet length of 15 mm) on the left, right and top sides, the ability of the air curtains to suppress water mist with different droplet sizes was studied, and the difference in intrusion between fine droplets and large droplets under the action of the air curtain was analyzed in particular.

[0069] 2) Experimental Design and Testing Conditions The experimental setup includes the following combination of operating conditions: Number of water spray nozzles: 3; Air curtain arrangement: left and right sides + top air curtain, with an outlet length of 15 mm for each side; Water droplet size conditions: Fine droplets: droplet diameter <100μm; Large droplets: Droplet diameter > 200 μm; Spraying time: 3 min, 5 min; After spraying, the mass (g) of residual water on the target surface was weighed to evaluate the inhibitory effect of the air curtain under different particle size water mist conditions.

[0070] 3) Summary of experimental data Table 2: Comparison of residual water mass under different droplet sizes

[0071] 4) Analysis of experimental results Experimental results show that the air curtain has a significant inhibitory effect on water mist of different particle sizes, but the inhibitory effect decreases with increasing droplet size. For fine droplets with a diameter of less than 100 μm, the air curtain can effectively change their trajectory and achieve efficient blocking; while for droplets with a diameter of more than 200 μm, due to their greater inertia, some droplets still break through the air curtain and enter the target area, but the overall residual amount is still significantly reduced compared to the case without an air curtain.

[0072] (2) Simulation verification Simulation 1:

[0073] 1) Simulation Purpose This study investigates the velocity distribution characteristics of the dual-first-nozzle air curtain under different nozzle angles (20°, 40°, 60°, 80°), with a focus on the following analysis: The velocity decay pattern at the exit point; Location and intensity of airflow convergence at the nozzle; The effect of nozzle angle on air curtain thickness, coverage distance, and stability; This provides a basis for subsequent water mist suppression and nozzle arrangement optimization.

[0074] 2) Simulation model parameters Number of nozzles: 2; Outlet length: 15 mm; Grille spacing: 10 mm; Inlet pressure: 5–17 kPa; Observation locations: 50 mm, 100 mm, and 150 mm from the nozzle outlet axial direction; Output: Speed ​​(m / s).

[0075] 3) Simulation Results and Trends The smaller the angle of the first nozzle, the farther the airflow converges and the narrower the air curtain; Table 3: Comparison of Air Curtain Convergence Locations and Characteristics at Different Angles

[0076] Velocity decay law: Proximal end (50 mm): Large velocity fluctuations, significantly affected by nozzle interaction; Mid-range (100 mm): The speed tends to stabilize, and the angle correlation is obvious; Distal end (150 mm): Energy attenuation is significant, and the larger the angle, the weaker the energy retention.

[0077] Large included angle characteristics (60°–80°): 60°: The peak velocity at the center is the highest (25–32 m / s), energy is concentrated but stability is poor; 80°: The peak velocity is high but the direction is deflected, forming an asymmetric air curtain; 20°: Energy is concentrated at the far end, forming a slender air curtain; 40°: Balanced performance, with optimal air curtain coverage thickness, stability, and protection distance.

[0078] 4) Configuration Comparison and Conclusion Optimal overall configuration: 40°, uniform coverage, moderate thickness, and stable speed; The suboptimal configuration is 60°, which is suitable for high disturbance or strong convection scenarios, but not for long-distance fog suppression. Not recommended configuration: 80°, as it causes airflow deflection and unstable air curtain.

[0079] (3) Conclusions from combined experiments and simulations With dual nozzles at a 40° angle, the air curtain thickness and coverage are optimal, and the protective performance is stable. The continuous positive pressure barrier formed by the air curtain can effectively isolate paint droplets and environmental particles, ensuring the reliable operation of lidar and cameras in high-fog working environments.

[0080] Simulation 2: Analysis of the influence of the upper air curtain nozzle angle under three-nozzle spraying conditions.

[0081] 1) Simulation Purpose In a three-nozzle spraying operation, by introducing an upper air curtain nozzle (second nozzle) on top of the left and right air curtains (first nozzles), the influence of the upper nozzle's installation angle on the three-dimensional air curtain formation characteristics is systematically studied, with a focus on the following: The spatial convergence point and intensity of the airflow from the upper side and the airflow from the left and right side air curtains; The ability of the upper air curtain to suppress vertical water mist intrusion; The continuity, coverage, and stability of the three-dimensional air curtain under different upper nozzle angles; This provides a simulation basis for selecting structural parameters and actual layout of the upper nozzle.

[0082] 2) Simulation model and parameter settings Number of nozzles: 3 (left and right sides + top) Left and right nozzle parameters: consistent with the optimal configuration in simulation 1 (nozzle angle 40°, outlet length 15 mm). Upper nozzle outlet length: 15 mm; Upper nozzle installation angle (relative to the horizontal direction): 5°, 7.5°, 10°; Inlet pressure range: 5–17 kPa; Observation area: The space below the nozzle outlet and above the target area; Key output parameters: airflow velocity distribution (m / s), streamline structure, and location of the confluence region.

[0083] 3) Simulation results and configuration characteristic analysis Table 4: Comparison of airflow convergence characteristics of different configurations

[0084] (1) Flow field characteristics analysis of configuration 5° When the angle between the first nozzle on the upper side is 5°, the airflow on the upper side merges with the air curtains on the left and right sides near the nozzle outlet, resulting in excessive concentration of airflow energy in the near-end region. Under this configuration, although the local velocity is high, the downward extension capability of the air curtain is limited, making it difficult to form a continuous and effective protective layer above the target area, and the ability to suppress vertical droplets at medium and long distances is insufficient.

[0085] (2) Flow field characteristics analysis of configuration 7.5° When the angle of the first nozzle on the upper side is adjusted to 7.5°, the airflow on the upper side merges with the air curtain on the left and right sides at a position of about 80 mm, and the three airflows form a stable three-dimensional air curtain structure. Under this configuration, the coverage area of ​​the air curtain is significantly expanded, the velocity distribution is relatively uniform, and a continuous positive pressure protective layer can be formed above the target area, which shows a good blocking effect on vertical and oblique water mist.

[0086] (3) Flow field characteristics analysis of configuration 10° When the angle of the first nozzle on the upper side increases to 10°, the airflow on the upper side is mainly emitted in the upward direction, making it difficult to form an effective coupling with the air curtain on the left and right sides. Simulation results show that under this configuration, there is an obvious airflow gap above the protected area, the continuity of the three-dimensional air curtain is destroyed, and the interception effect of the upper air curtain on water mist is significantly weakened.

[0087] 4) Simulation Conclusions The angle of the upper nozzle has a decisive influence on the overall protective performance of the three-nozzle air curtain system; The 7.5° upper nozzle configuration performs best in terms of airflow convergence position, three-dimensional air curtain continuity and stability; if the upper nozzle angle is too small (5°), it is easy to cause airflow to overlap prematurely and the protection distance is insufficient; if the upper nozzle angle is too large (10°), it is difficult to form an effective three-dimensional air curtain cooperative structure.

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A spray painting drone, characterized in that, include: The main body of the drone; A spraying assembly, mounted on the main body of the drone, is used for atomizing and spraying paint. A sensor assembly is mounted on the main body of the drone and faces the spraying direction of the spraying assembly, for ranging and monitoring the spraying status; An air curtain protection component is installed on the main body of the UAV, including two first nozzles disposed on both sides of the sensor component and a first air source connected to the first nozzles. The first nozzles are strip-shaped and tilted towards the detection area of ​​the sensor component, and can form two symmetrical thin air curtains. The front ends of the two thin air curtains merge to form an air curtain barrier. The outer layer of the air curtain barrier can constrain the diffusion of fog droplets, control the range of fog beams, and reduce surrounding air disturbance. The inner layer of the air curtain barrier is in close contact with the front of the sensor assembly, forming a local positive pressure barrier and preventing droplets from contacting the sensor assembly.

2. The painting drone as described in claim 1, characterized in that: The sensor assembly includes an image acquisition unit and a distance sensing unit. The distance sensing unit is used to sense the distance between the UAV body and the spraying carrier, and the image acquisition unit is used to capture image information of the sprayed surface in real time.

3. The painting drone as described in claim 1, characterized in that: The air curtain protection assembly also includes a distributor disposed at the outlet end of the first air source. The distributor has two outlet ends and is used to divide the airflow into two paths, which are then connected to the two first nozzles respectively.

4. The painting drone as described in claim 1, characterized in that: It also includes a mounting bracket, with the two first nozzles symmetrically arranged on both sides of the mounting bracket to form a splash-proof mounting area with an open front end, and the sensor assembly is installed in the splash-proof mounting area.

5. The painting drone as described in claim 4, characterized in that: A transparent protective cover is detachably installed at the front open end of the splash-proof installation area.

6. The painting drone as described in claim 1, characterized in that: The angle between the air outlet direction of the first nozzle and the axis of the sensor assembly is 35°-45°.

7. The painting drone as described in claim 1, characterized in that: The air curtain protection assembly also includes a strip-shaped second nozzle and a second air source connected to the second nozzle. The second nozzle is horizontally positioned above the sensor assembly and tilted upwards to provide supplementary protection against the intrusion of mist droplets above the sensor assembly.

8. The painting drone as described in claim 7, characterized in that: The angle between the air outlet direction of the second nozzle and the horizontal plane is 5°-10°.

9. A method for operating a spray painting drone, characterized in that, Includes the following steps: S1. The main body of the drone approaches the target surface, completes precise positioning through lidar and camera, and hovers at a predetermined position in front of the target wall or component; At this time, the air curtain protection component is in a low-flow standby state to ensure that the surface of the sensor component is not affected by the initial environmental traces of paint mist droplets; S2. The air curtain protection component automatically switches to high flow mode to form a multi-layer air curtain and constitute an air curtain barrier. Among them, the outer layer of the air curtain barrier constrains the diffusion of sprayed droplets, controls the range of the mist beam, and reduces the disturbance of the surrounding air. The inner layer of the air curtain barrier is placed close to the front of the lidar and camera, forming a local positive pressure barrier to prevent fog droplets from contacting the sensors. S3. The spraying assembly starts and begins spraying paint. The laser radar monitors the spray distance in real time to keep the nozzle at the optimal angle and distance from the wall, reducing the rebound and splashing caused by droplet impact from the source and improving the uniformity of spraying. During this process, the spray droplets are effectively shaped under the action of the air curtain barrier, making the spraying effect controllable. At the same time, a stable pressure difference is maintained around the sensor assembly, preventing paint droplets from approaching the sensor assembly. S4. After the spraying operation is completed, the spraying component stops outputting paint, and the air curtain protection component reduces its power to low and enters standby mode. S5. The system is ready to execute the next spraying task, or move to the next work position according to the preset path, or return to base.

10. The method for operating a spraying drone as described in claim 9, characterized in that: When the sensor components are accidentally contaminated or malfunction, the spraying operation is suspended and the device is moved back to a safe distance. At the same time, the air curtain protection component automatically switches to high flow mode and performs continuous blowing and cleaning. If the sensor components return to normal, the painting operation will continue. If the sensor components fail to recover, the painting operation will end and the machine will automatically return to base.

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