A precision spraying method and apparatus

Abstract

A precise spraying method and device are used for automatic coating of a workpiece, the method comprising: a workpiece pose acquisition step; a spraying trajectory planning step, according to the workpiece pose information, determining the actual spatial appearance of the workpiece surface and the spraying accessible area boundary, and generating a corresponding spraying trajectory; a spraying mechanism control step; a spraying output control step, in the spraying process, based on the mapping relationship model between the spraying amount and the movement speed, adjusting the spraying flow, and realizing uniform control of the unit area coating thickness; a multi-color spraying cleaning color changing step, when multi-color spraying is required, the quick change between different color coatings is completed through a color changing paint supply system. According to the present application, combined with machine vision positioning, multi-axis linkage control and dynamic adjustment of spraying parameters, local precise spraying without protective shielding conditions can be realized, and it is suitable for automatic coating of automobile hubs, aluminum parts and other complex curved surface products.

Description

Technical Field

[0001] This invention relates to the field of automated coating technology, and in particular to a precise spraying method and apparatus for multi-layer, composite-layer, and multi-color local spraying of complex curved workpieces. Background Technology

[0002] As automotive wheels, auto parts, and aluminum alloy products develop towards personalization and high quality, multi-color, multi-pattern, and composite coating processes are being used more and more widely. Especially in processes such as partial wheel decoration, multi-color overlay, combination spraying of clear varnish and colored varnish, and composite spraying of different functional coatings, higher requirements are being placed on the precision of spraying boundaries, the consistency of overlap between different coatings, and the overall appearance quality of the product.

[0003] Currently, for multi-color or composite coating products, masking tape, photomasks, or specialized tooling are commonly used to protect non-coating areas before applying different colors or coatings in stages. While this process can meet the production requirements of some products, it has the following shortcomings:

[0004] (1) Each time a new color or coating is added, an additional masking, removal and cleaning process is required, which makes the process complex and the production cycle long;

[0005] (2) Different products and patterns require different specifications of masks or tooling, which results in higher manufacturing and maintenance costs and is not conducive to flexible production;

[0006] (3) The masking positioning accuracy is greatly affected by manual operation and tooling assembly errors, which can easily lead to quality defects such as rough edges, misalignment, missed spraying or over-spraying at the color junction.

[0007] (4) For automotive wheel hub windows, spoke edges, complex curved surfaces and irregular areas, due to the complex spatial structure, traditional masking methods are difficult to install and it is difficult to guarantee the accuracy and consistency of the spraying boundary.

[0008] On the other hand, while existing automated spraying equipment can achieve automated robotic spraying, most of them use pre-taught trajectories for spraying control. When there are clamping deviations, dimensional tolerances, or model changes in the workpiece, it is difficult to correct the spray gun trajectory in real time, especially in the multi-color boundary area, which is prone to problems such as spraying position deviation, unclear boundaries, repeated spraying, or missed spraying, making it difficult to meet the requirements of precise spraying of composite coatings and multi-color coatings.

[0009] Therefore, how to achieve high-precision boundary control of multi-layer, composite-layer, and multi-color spraying areas on complex curved workpieces with reduced or even no protective shielding, improve the positional consistency and overlap accuracy between different colors and different coatings, and at the same time take into account the ability to quickly switch between different products and different patterns has become an urgent technical problem to be solved in the field of automated precision spraying. Summary of the Invention

[0010] To address the aforementioned problems, the present invention aims to provide a precise spraying method and apparatus.

[0011] According to one aspect of the present invention, a precision spraying method is provided for automated coating of workpieces, characterized by comprising the following steps:

[0012] S1. Workpiece pose acquisition step, used to acquire image information and six-degree-of-freedom spatial position of the workpiece, establish the transformation relationship between the workpiece coordinate system, camera coordinate system and painting robot coordinate system, and obtain workpiece pose information;

[0013] S2. Spraying trajectory planning steps: Based on the workpiece pose information, scan the workpiece surface using a camera to construct a three-dimensional curved surface model of the workpiece, determine the actual spatial shape of the workpiece surface and the boundary of the spraying reachable area; generate a target spraying model based on the preset spraying task data including the spraying pattern outline, spatially map the spraying pattern outline with the workpiece three-dimensional curved surface model, convert the two-dimensional pattern information into the spraying area on the corresponding three-dimensional curved surface, establish a spraying coverage model based on the three-dimensional curved surface model and the target spraying model, and generate the corresponding spraying trajectory;

[0014] S3. Spraying mechanism control steps, used to drive the spray gun to perform spraying tasks;

[0015] S4. Spraying material output control steps: During the spraying process, the spraying output state is adjusted by controlling the spraying amount and spraying effect. Among them, the spraying flow rate is adjusted based on the mapping relationship model between the spraying amount and the movement speed to achieve uniform control of the coating thickness per unit area.

[0016] S5. Multi-color spraying cleaning and color change steps: When multi-color spraying is required, the color change paint supply system completes the quick change between different colors of paint. Before switching to different colors, the pipeline is automatically cleaned, and then the corresponding color paint is delivered to the spraying actuator.

[0017] According to another aspect of the present invention, a precision spraying apparatus is provided, characterized in that it comprises the following modules for implementing the above-described precision spraying method:

[0018] The workpiece pose acquisition module is used to acquire the image information and six-degree-of-freedom spatial position of the workpiece, establish the transformation relationship between the workpiece coordinate system, the camera coordinate system and the painting robot coordinate system, and obtain the workpiece pose information.

[0019] The spraying trajectory planning module scans the workpiece surface using a camera based on the workpiece pose information, constructs a three-dimensional curved surface model of the workpiece, and determines the actual spatial shape of the workpiece surface and the boundary of the spraying reachable area; it generates a target spraying model based on preset spraying task data including the spraying pattern outline, spatially maps the spraying pattern outline with the workpiece three-dimensional curved surface model, converts the two-dimensional pattern information into the spraying area on the corresponding three-dimensional curved surface, establishes a spraying coverage model based on the three-dimensional curved surface model and the target spraying model, and generates the corresponding spraying trajectory;

[0020] The spraying mechanism control module is used to drive the spray gun to perform spraying tasks;

[0021] The spraying output control module adjusts the spraying output state by controlling the spraying amount and spraying effect during the spraying process. Specifically, it adjusts the spraying flow rate based on the mapping relationship model between the spraying amount and the movement speed to achieve uniform control of the coating thickness per unit area.

[0022] The multi-color spraying cleaning and color-changing module can quickly switch between different colors of paint when multi-color spraying is required. Before switching to a different color, it automatically cleans the pipeline and then delivers the corresponding color paint to the spraying actuator.

[0023] According to the present invention, machine vision positioning, multi-axis linkage control and dynamic adjustment of spraying parameters can be combined to achieve local precision spraying under conditions without protective shielding, which is applicable to the automated coating of automobile wheel hubs, aluminum parts and other complex curved surface products. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of a precision spraying method according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of a precision spraying method and apparatus according to an embodiment of the present invention; Detailed Implementation

[0027] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The exemplary embodiments described below and illustrated in the drawings are intended to teach the principles of the invention, enabling those skilled in the art to implement and use the invention in various environments and for various applications. Therefore, the scope of protection of the present invention is defined by the appended claims, and the exemplary embodiments are not intended, and should not be considered, a limiting description of the scope of protection of the present invention. Furthermore, for ease of description, the dimensions of the various parts shown in the drawings are not necessarily drawn to actual scale. Orientation descriptions, such as the longitudinal direction corresponding to the length of the main body, and the orientations or positional relationships indicated by up, down, left, right, top, bottom, etc., are based on the orientations or positional relationships shown in the drawings and are only for the purpose of facilitating the description of the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise specifically stated, the order and numerical values ​​of the components and assembly steps described in the embodiments do not limit the scope of the present invention. Moreover, any numerical range stated herein is intended to include all sub-ranges contained therein, and a numerical range expressed as "numerical value A to numerical value B" refers to a range including endpoints numerical values ​​A and B. Those skilled in the art will understand that the terms "nth" and "Sn" in this invention are used only to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them. For example, steps S3 and S4 may be parallel, while S6 can be a feedback control step that simultaneously targets steps S3 and S4, and is not limited to... Figure 1 The illustrated sequence relationship.

[0028] <Exemplary Method>

[0029] This invention provides a precision spraying method that enables precise control of spraying boundaries, simplifies color matching processes, and efficiently sprays product patterns. It is flexible and compatible with various product patterns and allows for rapid color changes, reducing wasted production capacity during product switchovers. The method is based on multi-axis linkage control, trajectory planning, and spraying parameter management of the spraying mechanism, achieving high-precision, multi-color, flexible, and automatic spraying of workpiece surfaces.

[0030] This method is achieved through, for example Figure 2 The equipment shown is used to achieve this, and includes: a conveying mechanism 1 for conveying a workpiece 7 in the form of, for example, a hub; a positioning mechanism 2 for fixing the workpiece 7 by means of a clamp; a spraying mechanism 3 in the form of a spray gun; a fine positioning vision 4 and a coarse positioning vision 5 for visual recognition; and a multi-axis motion mechanism 6 in the form of a six-degree-of-freedom robotic arm or a multi-axis gantry system, which includes, but is not limited to, three-axis and six-axis motion mechanisms.

[0031] The method includes the following steps:

[0032] S1. Workpiece Pose Acquisition Steps: Before the spraying operation begins, the incoming workpiece is randomly oriented and initially fixed by a fixture. Subsequently, coarse positioning vision (e.g., using an industrial vision acquisition system) is employed to acquire image information of the workpiece after fixture fixation. Combined with a calibration plate or feature point detection method, and a pose calculation method based on feature point matching, the precise acquisition of the workpiece's six-degree-of-freedom spatial position is achieved. Workpiece pose estimation is performed, establishing the transformation relationship between the workpiece coordinate system, camera coordinate system, and spraying robot coordinate system to obtain workpiece pose information.

[0033] S2. Spraying trajectory planning step: Based on the workpiece pose information, a fine positioning vision system (hereinafter collectively referred to as a camera) is used to scan the workpiece surface to obtain dense or semi-dense point cloud data. The point cloud data is then processed by denoising, outlier filtering, point cloud registration, surface reconstruction, normal vector estimation, and curvature calculation to construct a high-precision three-dimensional surface model of the workpiece and determine the actual spatial morphology of the workpiece surface and the boundary of the spraying reachable area.

[0034] Simultaneously, a target spraying model is generated based on preset spraying task data. The spraying task data includes parameters such as the spraying area location, spraying pattern outline, spraying color information, spraying sequence, number of spraying layers, and target coating thickness requirements. The spraying pattern outline is then spatially mapped to the workpiece's three-dimensional curved surface model, converting the two-dimensional pattern information into a spraying area on the corresponding three-dimensional curved surface. A spraying coverage model is established based on the aforementioned 3D curved surface model and target spraying model. Corresponding spraying trajectories are generated according to the spray gun's spray width, spraying distance, movement speed, and coating thickness requirements. These trajectories are planned using a surface parameterization method and adaptively adjusted based on changes in workpiece surface curvature. Specifically, trajectory density is increased in areas of high curvature and decreased in areas of low curvature. Compensation paths are added in pattern boundary areas to improve spraying boundary accuracy and coverage uniformity. For multi-color spraying areas, independent spraying paths for each color are generated based on the positional relationship, spraying sequence, and layer requirements of different color areas. The generated paths are optimized using a trajectory smoothing algorithm to reduce speed abrupt changes and acceleration impacts during multi-axis motion. The final output is a multi-dimensional spraying execution trajectory containing information on the spray gun's spatial position, spray gun attitude angle, movement speed, spraying flow rate, spraying color, and number of spray layers.

[0035] S3. Spraying Mechanism Control Steps: Control a six-degree-of-freedom robotic arm or multi-axis gantry system to drive the spray gun to perform the spraying task. The control process includes: inverse kinematics solution for the spray gun end-effector pose, attitude constraint control (maintaining an angle between the spray gun and the surface normal), velocity planning and acceleration constraint control, trajectory error compensation mechanism, and real-time correction of motion errors through a closed-loop control system.

[0036] S4. Spraying output control steps: During the spraying process, the spraying flow rate is dynamically adjusted according to the following parameters by controlling the control components of the spray gun: movement speed, surface curvature, and unit area coverage requirements. A mapping relationship model between the spraying amount and the movement speed is established to achieve uniform control of the coating thickness per unit area.

[0037] By adjusting the spraying output state, precise control of the spraying amount and spraying effect can be achieved, wherein the spray gun is a non-atomizing paint spray gun (preferably a piezoelectric dispensing valve or an ultrasonic spray gun).

[0038] S5. Multi-color spraying cleaning and color-changing steps: When multi-color spraying is required, the color-changing paint supply system facilitates quick switching between different colors. Before switching to a different color, the system automatically cleans the pipeline and then delivers the corresponding color paint to the spraying mechanism. During multi-color spraying, the system executes the following control flow: detects the completion status of the current spraying color, activates the paint supply switching valve group, performs high-pressure cleaning of the pipeline, determines the completion status of cleaning based on the fluid residue detection model, and switches to the target color spraying, thus achieving continuous or segmented multi-color spraying operations.

[0039] S6. Multi-axis linkage and parameter adjustment steps: During the spraying process, the multi-axis movement of the spray gun is coordinated and controlled according to the preset spraying process parameters, and the spraying speed, material output status and spraying trajectory are adjusted to ensure the stability and consistency of the spraying process.

[0040] S7. Human-computer interaction and data management steps: Set spraying parameters, display the status of the spraying process, and record and manage relevant data of the spraying operation through human-computer interaction.

[0041] <Exemplary device>

[0042] Correspondingly, the present invention provides a precision spraying device, comprising the following modules:

[0043] Includes the following modules:

[0044] The workpiece pose acquisition module is used to acquire the image information and six-degree-of-freedom spatial position of the workpiece, establish the transformation relationship between the workpiece coordinate system, the camera coordinate system and the painting robot coordinate system, and obtain the workpiece pose information.

[0045] The spraying trajectory planning module scans the workpiece surface using a camera based on the workpiece pose information, constructs a three-dimensional curved surface model of the workpiece, and determines the actual spatial shape of the workpiece surface and the boundary of the spraying reachable area; it generates a target spraying model based on preset spraying task data including the spraying pattern outline, spatially maps the spraying pattern outline with the workpiece three-dimensional curved surface model, converts the two-dimensional pattern information into the spraying area on the corresponding three-dimensional curved surface, establishes a spraying coverage model based on the three-dimensional curved surface model and the target spraying model, and generates the corresponding spraying trajectory;

[0046] The spraying mechanism control module is used to drive the spray gun to perform spraying tasks;

[0047] The spraying output control module adjusts the spraying output state by controlling the spraying amount and spraying effect during the spraying process. Specifically, it adjusts the spraying flow rate based on the mapping relationship model between the spraying amount and the movement speed to achieve uniform control of the coating thickness per unit area.

[0048] The multi-color spraying cleaning and color-changing module can quickly change between different colors of paint through the color-changing paint supply system when multi-color spraying is required. Before switching to different colors, it automatically cleans the pipeline and then delivers the corresponding color paint to the spraying actuator.

[0049] The multi-axis linkage and parameter adjustment module, based on the detection and feedback of the spraying results by the vision detection feedback module, coordinates and controls the multi-axis movement of the spray gun according to the preset spraying process parameters, and adjusts the spraying speed, material output status and spraying trajectory to ensure the stability and consistency of the spraying process.

[0050] The human-computer interaction and data management module allows users to set spraying parameters, display the spraying process status, and record and manage relevant data for the spraying operation through human-computer interaction.

[0051] <Technical Effects>

[0052] According to the present invention, the following beneficial effects are achieved:

[0053] (1) The present invention acquires the spatial pose information of the workpiece through a vision acquisition system and establishes a mapping relationship between the workpiece coordinate system and the spraying equipment coordinate system, thereby realizing automatic identification and precise positioning of the workpiece during the spraying process, reducing the spraying position error caused by factors such as workpiece clamping deviation and conveying offset, and improving the stability of the spraying process.

[0054] (2) The present invention obtains three-dimensional data of the workpiece surface through three-dimensional vision perception technology, establishes a three-dimensional curved surface model of the workpiece, and generates a spraying trajectory based on the actual geometric shape of the workpiece. Compared with the traditional fixed trajectory spraying method, it can adapt to the spraying needs of workpieces with different sizes, different structures and complex curved surfaces, and improve the matching accuracy between the spraying trajectory and the workpiece surface.

[0055] (3) The present invention uses an adaptive trajectory planning method based on curvature analysis to dynamically adjust the spraying path density, spray gun speed and spraying posture according to the curvature change of the workpiece surface, so as to make the spraying area coverage more uniform, reduce the problems of overspray, underspray and inconsistent spraying thickness, and improve the coating quality.

[0056] (4) The present invention controls the movement of the spraying mechanism through a multi-axis linkage motion mechanism, so that the position, posture and spraying distance of the spray gun can be adjusted synchronously, and the spray gun can maintain a reasonable spraying angle with the workpiece surface, which is especially suitable for the precise spraying of complex free-curved parts such as wheel hubs.

[0057] (5) The present invention adopts a precision spraying material control method. By controlling the material output status of the spraying mechanism in real time, the spraying amount can be precisely adjusted. Compared with the traditional atomized spraying method, it can reduce paint scattering loss, improve paint utilization rate, and reduce spraying environmental pollution.

[0058] (6) This invention achieves rapid switching between different colored paints through a multi-color paint supply switching system and an automatic cleaning control method, reduces manual color changing operations, improves the production efficiency of multi-color spraying, and at the same time reduces the color mixing problem caused by pipeline residues, thereby improving the consistency of multi-color spraying quality.

[0059] (7) The present invention detects the spraying results through a visual inspection feedback module and feeds the detection data back to the control system, thereby realizing the dynamic correction of the spraying trajectory, spraying parameters and local spraying strategy, so that the spraying process is transformed from traditional open-loop control to closed-loop control, improving spraying accuracy and product consistency.

[0060] (8) This invention can achieve precise spraying of complex patterns, local areas and multi-color areas without the need for traditional masking, film application and other auxiliary processes, thereby reducing the consumption of auxiliary materials, reducing labor costs and improving production flexibility.

[0061] (9) The present invention adopts a modular structure design, which can be configured with three-axis, six-axis robotic arms or other multi-degree-of-freedom motion mechanisms according to different workpiece types. It has strong adaptability and expansion capability, and can be applied to the automated flexible production of automobile wheel hubs, aluminum alloy parts and other complex structural parts.

[0062] (10) This invention achieves digitalization and intelligentization of the spraying process through the comprehensive application of visual perception, intelligent path planning, multi-axis collaborative control and spraying parameter management, improves the level of automated production, and meets the needs of high-precision, high-efficiency and multi-variety flexible manufacturing.

[0063] In the description of this application, "a plurality of" means two or more, unless otherwise expressly specified. Unless otherwise expressly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Although the invention has been described with reference to various specific embodiments, it should be understood that modifications can be made within the spirit and scope of the described inventive concept. Therefore, it is intended that the invention be limited to the described embodiments but will have the full scope defined by the language of the appended claims.

Claims

1. A precision spraying method for automated coating of workpieces, characterized in that, Includes the following steps: S1. Workpiece pose acquisition step, used to acquire image information and six-degree-of-freedom spatial position of the workpiece, establish the transformation relationship between the workpiece coordinate system, camera coordinate system and painting robot coordinate system, and obtain workpiece pose information; S2. Spraying trajectory planning steps: Based on the workpiece pose information, scan the workpiece surface using a camera to construct a three-dimensional curved surface model of the workpiece, determine the actual spatial shape of the workpiece surface and the boundary of the spraying reachable area; generate a target spraying model based on the preset spraying task data including the spraying pattern outline, spatially map the spraying pattern outline with the workpiece three-dimensional curved surface model, convert the two-dimensional pattern information into the spraying area on the corresponding three-dimensional curved surface, establish a spraying coverage model based on the three-dimensional curved surface model and the target spraying model, and generate the corresponding spraying trajectory; S3. Spraying mechanism control steps, used to drive the spray gun to perform spraying tasks; S4. Spraying material output control steps: During the spraying process, the spraying output state is adjusted by controlling the spraying amount and spraying effect. Among them, the spraying flow rate is adjusted based on the mapping relationship model between the spraying amount and the movement speed to achieve uniform control of the coating thickness per unit area. S5. Multi-color spraying cleaning and color change steps: When multi-color spraying is required, the color change paint supply system completes the quick change between different colors of paint. Before switching to different colors, the pipeline is automatically cleaned, and then the corresponding color paint is delivered to the spraying actuator.

2. The precision spraying method according to claim 1, characterized in that, It also includes: step S6. Multi-axis linkage and parameter adjustment step, in which, based on the detection and feedback of the spraying results by the vision detection feedback module, the multi-axis movement of the spray gun is coordinated and controlled according to the preset spraying process parameters, and the spraying speed, material output status and spraying trajectory are adjusted to ensure the stability and consistency of the spraying process; and / or, step S7. Human-machine interaction and data management step, in which the spraying parameters are set through human-machine interaction, the spraying process status is displayed, and the relevant data of the spraying operation are recorded and managed.

3. The precision spraying method according to claim 1, characterized in that, In step S1, workpiece pose acquisition, before the spraying operation begins, the incoming workpiece with a random orientation is initially fixed by a fixture, the workpiece image information is acquired by a vision acquisition system, and the six-degree-of-freedom spatial position of the workpiece is obtained by combining a calibration plate or feature point detection method and a pose calculation method based on feature point matching. The workpiece pose is estimated to obtain the workpiece pose information.

4. The precision spraying method according to claim 1, characterized in that, In step S2, the spraying trajectory planning step, a structured light camera, laser profilometer or multi-view vision system is used to scan the workpiece surface to obtain dense or semi-dense point cloud data. The point cloud data is then processed by denoising, outlier filtering, point cloud registration, surface reconstruction, normal vector estimation and curvature calculation to construct a three-dimensional surface model of the workpiece.

5. The precision spraying method according to claim 4, characterized in that, In step S2, the spraying trajectory planning step, the spraying task data also includes the spraying area location, spraying color information, spraying sequence, number of spraying layers, and target coating thickness requirements; the corresponding spraying trajectory is generated based on the spray gun's spray width range, spraying distance, movement speed, and coating thickness requirements.

6. The precision spraying method according to claim 5, characterized in that, The spraying trajectory is planned using a surface parameterization method and adaptively adjusted according to changes in the workpiece surface curvature. Specifically, the trajectory density is increased in areas with high curvature and decreased in areas with low curvature. Compensation paths are added in pattern boundary areas to improve spraying boundary accuracy and coverage uniformity. For multi-color spraying areas, independent spraying paths for each color are generated based on the positional relationship, spraying sequence, and layer requirements of different color areas. The generated paths are then optimized using a trajectory smoothing algorithm to reduce speed abrupt changes and acceleration impacts during multi-axis motion. The final output is a multi-dimensional spraying execution trajectory containing information on the spray gun's spatial position, spray gun attitude angle, movement speed, spraying flow rate, spraying color, and number of spraying layers.

7. The precision spraying method according to claim 1, characterized in that, In the S3. Spraying mechanism control steps, the control process includes: inverse kinematics solution of the spray gun end pose, attitude constraint control for maintaining the angle between the spray gun and the surface normal, speed planning and acceleration constraint control, trajectory error compensation mechanism, and real-time correction of motion error through closed-loop control system.

8. The precision spraying method according to claim 1, characterized in that, In step S4, spraying material control, during the spraying process, the spraying flow rate is adjusted according to the spraying speed, the curvature of the spraying area, and the coverage requirements per unit area by controlling the spray gun control components.

9. The precision spraying method according to claim 8, characterized in that, In the S5 multi-color spraying cleaning and color change step, the following control process is executed during the multi-color spraying process: detect the end status of the current spraying color, start the paint supply switching valve group, perform high-pressure cleaning of the pipeline, determine the cleaning completion status based on the fluid residue detection model, switch to the target color spraying, and realize continuous or segmented multi-color spraying operations.

10. A precision spraying device, characterized in that, The method for implementing the precise spraying method according to any one of claims 1 to 9 includes the following modules: The workpiece pose acquisition module is used to acquire the image information and six-degree-of-freedom spatial position of the workpiece, establish the transformation relationship between the workpiece coordinate system, the camera coordinate system and the painting robot coordinate system, and obtain the workpiece pose information. The spraying trajectory planning module scans the workpiece surface using a camera based on the workpiece pose information, constructs a three-dimensional curved surface model of the workpiece, and determines the actual spatial shape of the workpiece surface and the boundary of the spraying reachable area; it generates a target spraying model based on preset spraying task data including the spraying pattern outline, spatially maps the spraying pattern outline with the workpiece three-dimensional curved surface model, converts the two-dimensional pattern information into the spraying area on the corresponding three-dimensional curved surface, establishes a spraying coverage model based on the three-dimensional curved surface model and the target spraying model, and generates the corresponding spraying trajectory; The spraying mechanism control module is used to drive the spray gun to perform spraying tasks; The spraying output control module adjusts the spraying output state by controlling the spraying amount and spraying effect during the spraying process. Specifically, it adjusts the spraying flow rate based on the mapping relationship model between the spraying amount and the movement speed to achieve uniform control of the coating thickness per unit area. The multi-color spraying cleaning and color-changing module can quickly switch between different colors of paint when multi-color spraying is required. Before switching to a different color, it automatically cleans the pipeline and then delivers the corresponding color paint to the spraying actuator.

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