A polyurea rotating spraying system for spherical thin-shell structure and spraying thickness consistency control method

Abstract

The application discloses a kind of polyurea rotary spraying systems and spraying thickness consistency control methods for spherical thin shell structure, comprising: workpiece clamping and rotating mechanism is set in the top of rack, for clamping and driving spherical thin shell workpiece to carry out composite rotation around its vertical axis and / or horizontal axis, spraying execution mechanism is installed in one end of the top of rack, spraying execution mechanism includes multiple degrees of freedom mechanical arm being set in one end of the top of rack, and spray gun assembly being installed in the end of mechanical arm;Thickness on-line detection unit is installed on or adjacent to spray gun assembly, for non-contact real-time measurement of the coating thickness of the surface of spherical thin shell workpiece already sprayed area, and generates thickness signal;Workpiece clamping and rotating mechanism, spraying execution mechanism and thickness on-line detection unit are electrically connected with control unit respectively.The application realizes full coverage, no dead angle spraying to the outer surface of spherical thin shell, significantly improves the overall thickness consistency and automation degree of the coating of spherical surface.

Description

Technical Field

[0001] This invention relates to a polyurea rotary spraying system and a method for controlling the consistency of spraying thickness for spherical thin-shell structures, belonging to the field of automated coating equipment and coating thickness control technology. Background Technology

[0002] Spherical thin-shell structures, such as spherical storage tanks, pressure vessels, aerospace spherical containers, and marine buoyancy spherical shells, are widely used in petrochemical, shipbuilding, marine engineering, and defense equipment fields due to their uniform stress distribution, small surface area, and high load-bearing capacity. To improve the service life of spherical thin-shell structures under harsh conditions such as corrosion, impact, and wear, a high-performance protective coating is usually applied to their outer surface. Polyurea elastomer materials, with their excellent corrosion resistance, high tensile strength, good wear resistance, and rapid curing characteristics, have become an ideal choice for the external protection of spherical thin-shell structures.

[0003] The curved geometry of a spherical thin-shell structure presents challenges for uniform coating. The curvature of the sphere varies continuously at different points on its surface, causing the deposition efficiency of the sprayed material to fluctuate with changes in spraying angle and distance. Polyurea materials exhibit a certain degree of fluidity before curing, making them prone to "sagging" in the lower half of the sphere under gravity, while thickness accumulation or inadequacy may occur in the equatorial region or at the edges. Traditional manual spraying relies on the operator's experience and skill, resulting in high labor intensity, low efficiency, and difficulty in ensuring consistent coating thickness, often leading to localized areas of excessive or insufficient thickness, resulting in reduced protective performance or material waste.

[0004] Existing automated spraying equipment includes some rotary spraying devices for rotating or planar workpieces, but lacks a closed-loop system capable of real-time online detection of spherical coating thickness and feedback to motion control and process parameter adjustment. The few methods using ultrasonic or laser thickness measurement are mostly used for flat or slowly moving workpieces; for rapidly rotating spherical thin-shell structures, detection lag and interference from curved surface reflections have not been effectively resolved. Therefore, achieving precise, consistent, and efficient control of the polyurea coating thickness on the outer surface of spherical thin-shell structures is a pressing technical problem to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is the high coating thickness dispersion caused by large changes in surface curvature and uneven material accumulation in existing spraying equipment.

[0006] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution.

[0007] On one hand, the present invention provides a polyurea rotary spraying system for spherical thin-shell structures, including: a frame, a workpiece clamping and rotating mechanism, a spraying execution mechanism, an online thickness detection unit, and a control unit;

[0008] The workpiece clamping and rotating mechanism is located on the top of the frame and is used to clamp and drive the spherical thin-shell workpiece to rotate in a compound manner around its vertical axis and / or horizontal axis. The spraying execution mechanism is installed at one end of the top of the frame.

[0009] The spraying actuator includes a multi-degree-of-freedom robotic arm disposed at one end of the top of the frame, and a spray gun assembly installed at the end of the robotic arm. The spray gun assembly is used to spray polyurea material onto the outer surface of the spherical thin-shell workpiece.

[0010] The online thickness detection unit is installed on or near the spray gun assembly and is used to non-contactly measure the coating thickness of the sprayed area on the surface of the spherical thin-shell workpiece in real time, and generate a thickness signal.

[0011] The workpiece clamping and rotating mechanism, the spraying execution mechanism, and the online thickness detection unit are all electrically connected to the control unit.

[0012] By coordinating a composite rotation mechanism around the vertical and horizontal axes with a multi-degree-of-freedom robotic arm, full-coverage, dead-angle-free spraying of the outer surface of a spherical thin shell is achieved; at the same time, by utilizing an online thickness detection unit and a control unit to form a real-time closed-loop feedback link, the overall thickness consistency and automation of the coating on the spherical surface are significantly improved.

[0013] The workpiece clamping and rotating mechanism includes: a base, a vertical rotation drive unit, a vertical turntable, a horizontal rotation drive unit, a horizontal turntable, and a workpiece clamping unit;

[0014] The vertical rotation drive unit is mounted on the base and is used to drive the vertical turntable to rotate around the vertical axis. The horizontal rotation drive unit is mounted on the vertical turntable and is used to drive the horizontal turntable to rotate around the horizontal axis. The workpiece clamping unit is disposed on the horizontal turntable and is used to fix the spherical thin-shell workpiece.

[0015] By defining a series-connected composite rotary structure that limits vertical drive and horizontal turntable, the polar angle motion and azimuth angle motion of the sphere can be independently decoupled, so that the workpiece rotation motion model and the robot arm trajectory planning correspond one-to-one, enhancing the system's adaptability to spraying processes under complex gravity fields.

[0016] The online thickness detection unit is a laser triangulation displacement sensor, a spectral confocal sensor, or an ultrasonic thickness sensor.

[0017] The spray gun assembly includes one or more spray guns, each with an independently adjustable spray fan angle and atomizing air pressure.

[0018] Secondly, the present invention provides a method for controlling the coating thickness consistency of a polyurea rotary spraying system for a spherical thin-shell structure, comprising:

[0019] Step S1: Clamp the spherical thin-shell workpiece on the workpiece clamping and rotating mechanism, and input the geometric parameters and target thickness distribution model of the spherical thin-shell workpiece into the control unit;

[0020] Step S2: The control unit plans the three-dimensional spraying trajectory on the surface of the spherical thin-shell workpiece according to the geometric parameters and the target thickness distribution model, and generates the composite rotational motion parameters of the workpiece clamping and rotating mechanism and the spatial pose parameters of the spray gun assembly corresponding to the three-dimensional spraying trajectory;

[0021] Step S3: The control unit controls the workpiece clamping and rotating mechanism to drive the spherical thin-shell workpiece to move according to the composite rotational motion parameters, and at the same time controls the spray gun assembly to perform polyurea spraying on the surface of the spherical thin-shell workpiece according to the spatial pose parameters;

[0022] Step S4: During the spraying process, the online thickness detection unit measures the coating thickness of the sprayed area in real time and feeds back the thickness signal to the control unit;

[0023] Step S5: The control unit compares the real-time thickness signal with the target thickness value of the corresponding point in the target thickness distribution model and calculates the thickness deviation; if the deviation is greater than the preset allowable deviation threshold, the control unit dynamically adjusts the composite rotational motion parameters, and / or the spatial pose parameters, and / or the spraying process parameters according to the preset closed-loop control algorithm to correct the coating thickness of the subsequent spraying points.

[0024] Step S6: Repeat steps S3 to S5 until the entire outer surface of the spherical thin-shell workpiece is coated.

[0025] By actively intervening in subsequent spraying parameters through online thickness comparison, random interference caused by air pressure fluctuations, temperature drift, or changes in material rheology during the spraying process can be effectively offset, thereby improving the controllability of the coating thickness across the entire surface.

[0026] Includes: The target thickness distribution model is based on spherical coordinates. function ,in, Polar angle, For azimuth, the function Considering the sag or edge effect caused by gravity, different target thickness values ​​are preset in different regions of the sphere to compensate for the thickness changes caused by material flow.

[0027] The dynamic adjustment in step S includes:

[0028] When the real-time thickness of a certain area is detected to be lower than the target thickness, the control unit performs operations such as reducing the rotation speed of the workpiece clamping and rotating mechanism, and / or reducing the moving speed of the spray gun assembly, and / or increasing the spray flow rate, and / or reducing the spray distance.

[0029] When the real-time thickness of a certain area is detected to be higher than the target thickness, the control unit performs operations such as increasing the rotation speed of the workpiece clamping and rotating mechanism, and / or increasing the moving speed of the spray gun assembly, and / or decreasing the spray flow rate, and / or increasing the spray distance.

[0030] The closed-loop control algorithm is either a proportional-integral-derivative control algorithm or a model predictive control algorithm.

[0031] It also includes: coating quality verification. After the full surface spraying is completed, the control unit generates an actual thickness distribution map based on all stored thickness signals, compares it with the target thickness distribution model, and outputs a full surface thickness consistency evaluation report.

[0032] By transforming the spraying process data into a visualized full-surface thickness distribution map and a quantitative evaluation report, digital traceability of process results is achieved, improving the efficiency and reliability of acceptance of spherical thin-shell coating quality in the aerospace or precision instrument fields.

[0033] The polyurea material is a two-component polyurea, and the spraying process parameters include the mixing ratio of the two components, the mixing temperature, the spraying pressure, and the atomizing air pressure.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0035] This invention utilizes a workpiece clamping and rotating mechanism to drive a sphere to rotate in a composite manner around its vertical and horizontal axes. Combined with a multi-degree-of-freedom robotic arm located at one end of the frame, this allows the spray gun assembly to approach any latitude and longitude region on the sphere's surface at an optimal normal angle, ensuring the continuity and coverage of the entire outer surface spraying trajectory. By integrating a non-contact online thickness detection unit on or near the spray gun assembly and electrically connecting it to the control unit, the thickness signal can be collected before the paint has fully leveled or cured. Furthermore, because the detection point is adjacent to the spray gun, the measurement data and the spraying point have extremely high spatial synchronization, providing a low-latency, highly correlated hardware data channel for the subsequent control unit to perform real-time deviation calculations. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the polyurea rotary spraying system for a spherical thin-shell structure as shown in Embodiment 1 of the present invention;

[0037] Figure 2 This is a schematic diagram of the workpiece clamping and rotating mechanism shown in Embodiment 1 of the present invention;

[0038] Figure 3 This is a flowchart illustrating the coating thickness consistency control method for a polyurea rotary spraying system for a spherical thin-shell structure, as shown in Embodiment 2 of the present invention.

[0039] Figure 4 This is a schematic diagram of the spherical coordinates of the target thickness distribution model on the surface of the spherical thin-shell workpiece shown in Embodiment 2 of the present invention;

[0040] Figure 5 This is a closed-loop control logic block diagram of dynamically adjusting parameters during the spraying process, as shown in Embodiment 2 of the present invention.

[0041] Reference numerals: 1-Frame; 2-Workpiece clamping and rotating mechanism; 21-Base; 22-Vertical rotation drive unit; 23-Vertical turntable; 24-Horizontal rotation drive unit; 25-Horizontal turntable; 26-Workpiece clamping unit; 3-Spraying execution mechanism; 31-Multi-degree-of-freedom robotic arm; 32-Spray gun assembly; 4-Thickness online detection unit; 5-Control unit; 6-Spherical thin-shell workpiece. Detailed Implementation

[0042] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0043] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0044] Example 1

[0045] This embodiment introduces a polyurea rotary spraying system for spherical thin-shell structures, including: a frame 1, a workpiece clamping and rotating mechanism 2, a spraying execution mechanism 3, an online thickness detection unit 4, and a control unit 5;

[0046] The workpiece clamping and rotating mechanism 2 is located on the top of the frame 1 and is used to clamp and drive the spherical thin-shell workpiece 6 to rotate in a compound manner around its vertical axis and / or horizontal axis. The spraying execution mechanism 3 is installed at one end of the top of the frame 1.

[0047] The spraying actuator 3 includes a multi-degree-of-freedom robotic arm 31 located at one end of the top of the frame 1, and a spray gun assembly 32 installed at the end of the robotic arm 31. The spray gun assembly 32 is used to spray polyurea material onto the outer surface of the spherical thin-shell workpiece 6.

[0048] The online thickness detection unit 4 is installed on or near the spray gun assembly 32 and is used for non-contact real-time measurement of the coating thickness of the sprayed area on the surface of the spherical thin-shell workpiece 6 and generates a thickness signal.

[0049] The workpiece clamping and rotating mechanism 2, the spraying execution mechanism 3, and the online thickness detection unit 4 are electrically connected to the control unit 5.

[0050] The workpiece clamping and rotating mechanism 2 includes: a base 21, a vertical rotation drive unit 22, a vertical turntable 23, a horizontal rotation drive unit 24, a horizontal turntable 25, and a workpiece clamping unit 26.

[0051] The vertical rotation drive unit 22 is mounted on the base 21 and is used to drive the vertical turntable 23 to rotate around the vertical axis. The horizontal rotation drive unit 24 is mounted on the vertical turntable 23 and is used to drive the horizontal turntable 25 to rotate around the horizontal axis. The workpiece clamping unit 26 is disposed on the horizontal turntable 25 and is used to fix the spherical thin-shell workpiece 6.

[0052] Specifically, for large spherical thin-shell structures with a diameter greater than 2m, an air bearing can be added to the workpiece clamping and rotating mechanism 2 to reduce the frictional resistance when the large workpiece rotates.

[0053] The online thickness detection unit 4 is a laser triangulation displacement sensor, a spectral confocal sensor, or an ultrasonic thickness sensor.

[0054] Specifically, the online thickness detection unit 4 can use a spectral confocal sensor instead of a laser triangulation sensor, which provides higher measurement accuracy for transparent or highly reflective surfaces.

[0055] The spray gun assembly 32 includes one or more spray guns, each with an independently adjustable spray fan angle and atomizing air pressure.

[0056] In this embodiment, such as Figure 1 As shown, the polyurea rotary coating system for spherical thin-shell structures includes a frame 1, a workpiece clamping and rotating mechanism 2, a coating execution mechanism 3, an online thickness detection unit 4, and a control unit 5.

[0057] Specifically, the frame 1 adopts a welded steel structure and is equipped with shock-absorbing pads at the bottom to provide stable support for the entire system.

[0058] Specifically, such as Figure 2As shown, the workpiece clamping and rotating mechanism 2 is mounted on the frame 1, including a base 21, a vertical rotation drive unit 22, a vertical turntable 23, a horizontal rotation drive unit 24, a horizontal turntable 25, and a workpiece clamping unit 26. The base 21 is fixed to the frame 1. The vertical rotation drive unit 22 is installed inside the base 21 and uses a servo motor in conjunction with a harmonic reducer to drive the vertical turntable 23 to rotate continuously 360° around the vertical axis. The horizontal rotation drive unit 24 is mounted on the vertical turntable 23 and uses a right-angle servo motor to drive the horizontal turntable 25 to rotate around the horizontal axis, with a rotation angle range of 0° to 180°. The workpiece clamping unit 26 is mounted on the horizontal turntable 25 and is a three-jaw self-centering chuck structure used to clamp and fix the spherical thin-shell workpiece 6.

[0059] Specifically, the spraying actuator 3 includes a multi-degree-of-freedom industrial robotic arm 31 mounted on the frame 1, and a spray gun assembly 32 installed at the end of the robotic arm 31. The spray gun assembly 32 includes one or more spray guns, each with an independently adjustable spray fan angle and atomizing air pressure. When a two-component polyurea material is used, the two components are mixed at the spray gun outlet and then atomized and sprayed out.

[0060] Specifically, the online thickness detection unit 4 is a laser triangulation displacement sensor, mounted on the housing of the spray gun assembly 32, used to measure the thickness of the coating immediately after spraying. This sensor moves synchronously with the robotic arm 31 along with the spray gun assembly 32, and the detection point always closely follows the spraying point.

[0061] Specifically, the control unit 5 is an industrial computer or embedded controller, which is electrically connected to the servo driver of the workpiece clamping and rotating mechanism 2, the robotic arm controller of the spraying execution mechanism 3, the spray gun assembly 32, and the online thickness detection unit 4, respectively. The control unit 5 has a built-in closed-loop control algorithm.

[0062] Example 2

[0063] Based on the same inventive concept as Example 1, this example introduces a method for controlling the coating thickness consistency of a polyurea rotary spraying system for spherical thin-shell structures, including:

[0064] Step S1: Clamp the spherical thin-shell workpiece 6 on the workpiece clamping and rotating mechanism 2, and input the geometric parameters and target thickness distribution model of the spherical thin-shell workpiece 6 into the control unit 5;

[0065] Step S2: The control unit 5 plans the three-dimensional spraying trajectory on the surface of the spherical thin-shell workpiece 6 according to the geometric parameters and the target thickness distribution model, and generates the composite rotational motion parameters of the workpiece clamping and rotating mechanism 2 and the spatial pose parameters of the spray gun assembly 32 corresponding to the three-dimensional spraying trajectory.

[0066] Step S3: Control unit 5 controls workpiece clamping and rotating mechanism 2 to drive spherical thin-shell workpiece 6 to move according to composite rotational motion parameters, and at the same time controls spray gun assembly 32 to spray polyurea on the surface of spherical thin-shell workpiece 6 according to spatial orientation parameters.

[0067] Step S4: During the spraying process, the online thickness detection unit 4 measures the coating thickness of the sprayed area in real time and feeds back the thickness signal to the control unit 5;

[0068] Step S5: Control unit 5 compares the real-time thickness signal with the target thickness value of the corresponding point in the target thickness distribution model and calculates the thickness deviation; if the deviation is greater than the preset allowable deviation threshold, control unit 5 dynamically adjusts the composite rotational motion parameters, and / or spatial pose parameters, and / or spraying process parameters according to the preset closed-loop control algorithm to correct the coating thickness of subsequent spraying points.

[0069] Step S6: Repeat steps S3 to S5 until the entire outer surface of the spherical thin-shell workpiece 6 is coated.

[0070] Includes: The target thickness distribution model is based on spherical coordinates. function ,in, Polar angle, For azimuth, the function Considering the sag or edge effect caused by gravity, different target thickness values ​​are preset in different regions of the sphere to compensate for the thickness changes caused by material flow.

[0071] The dynamic adjustments in step S5 include:

[0072] When the real-time thickness of a certain area is detected to be lower than the target thickness, the control unit 5 performs operations such as reducing the rotation speed of the workpiece clamping and rotating mechanism 2, and / or reducing the moving speed of the spray gun assembly 32, and / or increasing the spray flow rate, and / or reducing the spray distance.

[0073] When the real-time thickness of a certain area is detected to be higher than the target thickness, the control unit 5 performs operations such as increasing the rotation speed of the workpiece clamping and rotating mechanism 2, and / or increasing the moving speed of the spray gun assembly 32, and / or decreasing the spray flow rate, and / or increasing the spray distance.

[0074] The closed-loop control algorithm is either proportional-integral-derivative control or model predictive control.

[0075] Specifically, the closed-loop control algorithm can use model predictive control to replace the proportional-integral-derivative control algorithm, which can simultaneously optimize multiple control parameters (rotation speed, spray gun movement speed, spray flow rate, spray distance), and has a faster response speed, making it especially suitable for large-sized spheres or high-viscosity polyurea materials.

[0076] It also includes: coating quality verification. After the full surface spraying is completed, the control unit 5 generates an actual thickness distribution map based on all stored thickness signals, compares it with the target thickness distribution model, and outputs a full surface thickness consistency evaluation report.

[0077] The polyurea material is a two-component polyurea. The spraying process parameters include the mixing ratio of the two components, the mixing temperature, the spraying pressure, and the atomizing air pressure.

[0078] In this embodiment, a polyurea protective coating is applied to a spherical steel thin-shell structure with a diameter of 800 mm and a wall thickness of 5 mm using a coating thickness consistency control method based on a polyurea rotary spraying system for spherical thin-shell structures.

[0079] The polyurea material used is a two-component sprayed polyurea elastomer with a target coating thickness of 2.0 mm and an allowable deviation of ±0.1 mm.

[0080] like Figure 3 As shown, the steps are as follows:

[0081] Step 1: The operator clamps the spherical thin-shell workpiece 6 onto the workpiece clamping part 26, and adjusts the chuck so that the center of the sphere coincides with the rotation center of the horizontal turntable 25. The workpiece geometric parameters and the target thickness distribution model are input into the human-machine interface of the control unit 5. In this embodiment, the workpiece diameter is 800mm, and the target coating thickness is 2.0mm. The control unit 5 automatically generates the target thickness distribution model. ,in, It is the polar angle (0°~180°, with 0° being the vertex). The azimuth angle is 0° to 360°. Considering the gravitational flow effect, different target thickness values ​​are preset in different regions of the sphere to compensate for the downward flow tendency of the material before curing.

[0082] Step 2: The control unit 5 plans a three-dimensional spraying trajectory covering the entire sphere based on the spherical geometric parameters and the target thickness model, and calculates the corresponding composite rotational motion parameters and spray gun spatial pose parameters.

[0083] Step 3: Control unit 5 starts the spraying program and controls the workpiece clamping and rotating mechanism 2 to drive the spherical thin-shell workpiece S to perform compound rotation. At the same time, the robotic arm 31 drives the spray gun assembly 32 to spray polyurea onto the workpiece surface according to the planned trajectory.

[0084] Step 4: During the spraying process, the online thickness detection unit 4 measures the coating thickness of the sprayed area in real time and feeds back the thickness signal to the control unit 5.

[0085] Step 5: As Figure 4As shown, the control unit 5 compares the real-time thickness signal with the target thickness value at the corresponding point in the target thickness distribution model and calculates the thickness deviation. If the deviation exceeds the preset allowable deviation threshold, the control unit 5 dynamically adjusts the composite rotational motion parameters, spatial pose parameters, and / or spraying process parameters according to the closed-loop control algorithm to correct the coating thickness at subsequent spraying points, such as... Figure 5 As shown.

[0086] Step 6: Repeat steps 3 to 5 until the entire outer surface of the spherical thin-shell workpiece 6 is coated.

[0087] Step 7: After the coating is completed, the control unit 5 generates an actual thickness distribution map based on all stored thickness signals, compares it with the target thickness distribution model, and outputs a full surface thickness consistency evaluation report.

[0088] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "up," "down," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limiting the invention.

[0089] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0090] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0091] 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 polyurea rotary spraying system for spherical thin-shell structures, characterized in that, include: The machine frame (1), workpiece clamping and rotating mechanism (2), spraying execution mechanism (3), online thickness detection unit (4) and control unit (5); The workpiece clamping and rotating mechanism (2) is located on the top of the frame (1) and is used to clamp and drive the spherical thin-shell workpiece (6) to rotate in a compound manner around its vertical axis and / or horizontal axis. The spraying execution mechanism (3) is installed at one end of the top of the frame (1). The spraying actuator (3) includes a multi-degree-of-freedom robotic arm (31) disposed at one end of the top of the frame (1), and a spray gun assembly (32) installed at the end of the robotic arm (31). The spray gun assembly (32) is used to spray polyurea material onto the outer surface of the spherical thin-shell workpiece (6). The online thickness detection unit (4) is installed on or near the spray gun assembly (32) and is used to non-contactly measure the coating thickness of the sprayed area on the surface of the spherical thin shell workpiece (6) in real time and generate a thickness signal. The workpiece clamping and rotating mechanism (2), the spraying execution mechanism (3), and the online thickness detection unit (4) are electrically connected to the control unit (5).

2. The polyurea rotary coating system for spherical thin-shell structures according to claim 1, characterized in that, The workpiece clamping and rotating mechanism (2) includes: a base (21), a vertical rotation drive unit (22), a vertical turntable (23), a horizontal rotation drive unit (24), a horizontal turntable (25), and a workpiece clamping unit (26). The vertical rotation drive unit (22) is mounted on the base (21) and is used to drive the vertical turntable (23) to rotate around the vertical axis. The horizontal rotation drive unit (24) is mounted on the vertical turntable (23) and is used to drive the horizontal turntable (25) to rotate around the horizontal axis. The workpiece clamping unit (26) is disposed on the horizontal turntable (25) and is used to fix the spherical thin shell workpiece (6).

3. The polyurea rotary coating system for spherical thin-shell structures according to claim 1, characterized in that, The online thickness detection unit (4) is a laser triangulation displacement sensor, a spectral confocal sensor, or an ultrasonic thickness sensor.

4. The polyurea rotary coating system for spherical thin-shell structures according to claim 1, characterized in that, The spray gun assembly (32) includes one or more spray guns, each of which has an independently adjustable spray fan angle and atomizing air pressure.

5. A method for controlling the uniformity of coating thickness in a polyurea rotary spraying system for a spherical thin-shell structure based on any one of claims 1 to 4, characterized in that, include: Step S1: Clamp the spherical thin-shell workpiece (6) on the workpiece clamping and rotating mechanism (2), and input the geometric parameters and target thickness distribution model of the spherical thin-shell workpiece (6) into the control unit (5); Step S2: The control unit (5) plans the three-dimensional spraying trajectory on the surface of the spherical thin-shell workpiece (6) according to the geometric parameters and the target thickness distribution model, and generates the composite rotational motion parameters of the workpiece clamping and rotating mechanism (2) and the spatial pose parameters of the spray gun assembly (32) corresponding to the three-dimensional spraying trajectory. Step S3: The control unit (5) controls the workpiece clamping and rotating mechanism (2) to drive the spherical thin-shell workpiece (6) to move according to the composite rotational motion parameters, and at the same time controls the spray gun assembly (32) to perform polyurea spraying on the surface of the spherical thin-shell workpiece (6) according to the spatial pose parameters; Step S4: During the spraying process, the online thickness detection unit (4) measures the coating thickness of the sprayed area in real time and feeds back the thickness signal to the control unit (5). Step S5: The control unit (5) compares the real-time thickness signal with the target thickness value of the corresponding point in the target thickness distribution model and calculates the thickness deviation; if the deviation is greater than the preset allowable deviation threshold, the control unit (5) dynamically adjusts the composite rotation motion parameters, and / or the spatial pose parameters, and / or the spraying process parameters according to the preset closed-loop control algorithm to correct the coating thickness of the subsequent spraying points; Step S6: Repeat steps S3 to S6 until the entire outer surface of the spherical thin-shell workpiece (6) is coated.

6. The method for controlling coating thickness consistency according to claim 5, characterized in that, include: The target thickness distribution model is based on spherical coordinates. function ,in, Polar angle, For azimuth, the function Considering the sag or edge effect caused by gravity, different target thickness values ​​are preset in different regions of the sphere to compensate for the thickness changes caused by material flow.

7. The method for controlling coating thickness consistency according to claim 5, characterized in that, The dynamic adjustment in step S5 includes: When the real-time thickness of a certain area is detected to be lower than the target thickness, the control unit (5) performs operations such as reducing the rotation speed of the workpiece clamping and rotating mechanism (2), and / or reducing the moving speed of the spray gun assembly (32), and / or increasing the spray flow rate, and / or decreasing the spray distance; When the real-time thickness of a certain area is detected to be higher than the target thickness, the control unit (5) performs operations such as increasing the rotation speed of the workpiece clamping and rotating mechanism (2), and / or increasing the moving speed of the spray gun assembly (32), and / or decreasing the spray flow rate, and / or increasing the spray distance.

8. The method for controlling coating thickness consistency according to claim 5, characterized in that, The closed-loop control algorithm is either a proportional-integral-derivative control algorithm or a model predictive control algorithm.

9. The method for controlling coating thickness consistency according to claim 5, characterized in that, Also includes: Coating quality verification: After the full surface spraying is completed, the control unit (5) generates an actual thickness distribution map based on all stored thickness signals, compares it with the target thickness distribution model, and outputs a full surface thickness consistency evaluation report.

10. The method for controlling coating thickness consistency according to claim 5, characterized in that, The polyurea material is a two-component polyurea, and the spraying process parameters include the mixing ratio of the two components, the mixing temperature, the spraying pressure, and the atomizing air pressure.

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