A coating inspection system and method

Abstract

This invention provides a coating inspection system and method, relating to the field of nondestructive testing technology. The coating inspection system includes a driving component, a terahertz scanning component, a correction and detection component, and a control component. The terahertz scanning component is located at the end of the driving component and is used to scan the coating along a scanning path under the drive of the driving component. The correction and detection component is located at the end of the driving component and is used to move synchronously with the terahertz scanning component under the drive of the driving component to detect the deviation between the current scanning pose and the target scanning pose of the coating at each scanning point. The control component is connected to the driving component, the terahertz scanning component, and the correction and detection component. This coating inspection system can accurately detect the coating quality on the surface of a test component with complex geometries.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and in particular to a coating testing system and method. Background Technology

[0002] In industries such as aerospace and power generation, coatings are crucial for the performance and lifespan of critical components, such as turbine blades. For example, thermal barrier coatings can protect metal substrates from extreme high-temperature erosion, thereby extending the service life of critical components. Therefore, accurate and comprehensive non-destructive testing of coating quality is a core requirement throughout the entire lifecycle of component manufacturing and maintenance.

[0003] However, existing nondestructive testing technologies have serious limitations when applied to components with complex curved surfaces and features, such as turbine blades. For example, ultrasonic testing relies on liquid coupling agents, and eddy current testing is sensitive to the geometry of the component (such as cooling holes on turbine blades), leading to distorted measurement results. Both technologies can only achieve thickness measurements with low accuracy. Furthermore, traditional offline programming based on CAD models also has its flaws. It assumes that the physical component is perfectly consistent with the CAD model. However, actual deviations caused by manufacturing tolerances, thermal deformation, or clamping errors can cause the test position to deviate, leading to measurement failure or decreased accuracy.

[0004] Therefore, how to accurately detect the coating quality on the surface of a component with a complex geometry is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a coating inspection system and method to solve the technical problem of how to accurately inspect the coating quality of the surface of a component with a complex geometry.

[0006] To address the above problems, the present invention provides a coating inspection system, comprising: Driver components; A terahertz scanning component is located at the end of the driving component and is used to scan the coating along the scanning path under the drive of the driving component. A correction detection component, located at the end of the driving component, is used to move synchronously with the terahertz scanning component under the drive of the driving component, to detect the deviation of the current scanning pose of the coating from the target scanning pose of the terahertz scanning component at each scanning point; and, A control component, connected to the drive component, the terahertz scanning component, and the correction and detection component, is used to control the drive component to drive the terahertz scanning component and the correction and detection component to move along the scanning path, control the drive component to correct the scanning pose of the terahertz scanning component according to the deviation amount, and generate a digital twin model of the coating according to the feedback terahertz time-domain signal and the corresponding spatial position information.

[0007] Optionally, the correction detection component includes a laser triangulation sensor or a trinocular vision measurement system.

[0008] Optionally, the terahertz scanning component includes a femtosecond laser and a photoconductive antenna, wherein the effective spectral width is 0.1-5THz, the signal-to-noise ratio is 60-200dB, the femtosecond laser pulse width is 80-120fs, and the repetition frequency is 80-100MHz.

[0009] The present invention also provides a coating detection method, employing the above-mentioned coating detection system, the coating detection method comprising: Obtain the scanning path of the terahertz scanning component on the coating; The terahertz scanning component is controlled to sequentially reach each scanning point according to the scanning path. When the terahertz scanning component reaches each scanning point, it first obtains the deviation between the current scanning pose of the terahertz scanning component and the target scanning pose of the coating. Based on the deviation, a pose correction amount is determined and applied to the terahertz scanning component. Then, the terahertz scanning component is controlled to scan the coating to obtain the terahertz time domain signal. The physical characteristic data of the coating are calculated based on the terahertz time-domain signals obtained at each of the scanning points, and the physical characteristic data includes at least the coating thickness. A digital twin model of the coating is generated based on the mapping relationship between the physical feature data obtained at each scanning point and the corresponding spatial location information.

[0010] Optionally, the step of determining the pose correction amount based on the deviation amount and applying it to the terahertz scanning component includes: Determine whether the deviation is within a preset deviation range; If so, the pose correction amount is determined to be zero, and the terahertz scanning component is controlled to maintain the current scanning pose; If not, the inverse of the deviation amount is used as the pose correction amount, and the scanning pose of the terahertz scanning component is corrected according to the pose correction amount so that the corrected scanning pose of the terahertz scanning component is the target scanning pose.

[0011] Optionally, the scanning pose includes the scanning incident angle and the scanning incident distance.

[0012] Optionally, when the physical feature data is the coating thickness, the step of calculating the physical feature data of the coating based on the terahertz time-domain signal of each scanning point includes: The time delay of the two reflection peaks at the upper and lower interfaces of the coating in the terahertz time-domain signal is obtained; Obtain the refractive index of the coating; The coating thickness is calculated using the following formula: ; In the formula, d is the coating thickness in meters (m); c is the speed of light of terahertz waves in a vacuum in meters per second (m / s). ν represents the time delay between the two reflection peaks at the upper and lower interfaces of the coating, in seconds; n is the refractive index of the coating, dimensionless.

[0013] Optionally, the physical characteristic data may further include at least one of coating porosity and coating phase transition.

[0014] Optionally, the digital twin model can be displayed as a color heatmap based on the mapping relationship between physical feature data and spatial location information to generate a three-dimensional rendering visualization model.

[0015] Optionally, the coating detection method further includes: Coating lifespan model determination: Obtain digital twin models of multiple coating samples at different life test stages throughout their entire life cycle, and form a historical dataset; Based on the historical dataset, the mapping relationship between the physical feature data of the coating samples and the remaining service life of the coating samples in the digital twin model is obtained through training, and a coating service life model is generated. Actual measurement and calculation: Obtain a digital twin model of the coating; Substitute the physical feature data from the digital twin model of the coating into the coating lifespan model to output the remaining lifespan of the coating.

[0016] The coating inspection system provided by this invention, through the aforementioned coating inspection method, can detect the current scanning pose of the terahertz scanning component at each scanning point based on the theoretical scanning path. It then corrects the scanning pose of the terahertz scanning component based on the deviation between the current and target scanning poses. This process, involving both actual detection and correction followed by actual detection, enables the terahertz scanning component to accurately detect the actual sampling points of the coating at each scanning point. This overcomes signal attenuation and pose deviation caused by complex curved surfaces, resulting in highly accurate terahertz time-domain signals for each sampling point. Furthermore, based on the mapping relationship between the accurate terahertz time-domain signals at each sampling point and the corrected, accurate spatial position information, a digital twin model that accurately characterizes the physical features of the coating is obtained, thereby accurately characterizing the coating quality and achieving precise detection of coating quality. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies 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 from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the coating inspection system provided in an embodiment of the present invention; Figure 2 This is a first flowchart of the coating detection method provided in an embodiment of the present invention; Figure 3 This is a second flowchart of the coating detection method provided in an embodiment of the present invention; Figure 4 This is a third flowchart of the coating detection method provided in an embodiment of the present invention; Figure 5 This is a fourth flowchart of the coating detection method provided in an embodiment of the present invention; Figure 6 This is the fifth flowchart of the coating detection method provided in the embodiment of the present invention; Figure 7 The coating detection method provided in this embodiment of the invention includes a graph showing the relationship between the echo amplitude and flight time obtained by the terahertz scanning component emitting terahertz waves at the scanning point to the coating.

[0019] Explanation of reference numerals in the attached figures: 201-Driver assembly; 202-Terahertz scanning assembly; 203-Correction and detection assembly; 204-Component under test; 205-Turntable; 206-PC terminal. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not 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 limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] 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 can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] Figure 1 This is a schematic diagram of a coating inspection system provided in an embodiment of the present invention. Figure 2 This is a first flowchart of a coating detection method provided in an embodiment of the present invention.

[0024] This embodiment provides a coating inspection system, such as Figure 1 As shown, the system includes a driving component 201, a terahertz scanning component 202, a correction and detection component 203, and a control component. The terahertz scanning component 202 is located at the end of the driving component 201 and is used to scan the coating along a scanning path under the drive of the driving component 201. The correction and detection component 203 is located at the end of the driving component 201 and is used to move synchronously with the terahertz scanning component 202 under the drive of the driving component 201 to detect the current scanning pose of the coating at each scanning point of the terahertz scanning component 202. The deviation from the target scanning pose; the control component is connected to the drive component 201, the terahertz scanning component 202 and the correction detection component 203, and is used to control the drive component 201 to drive the terahertz scanning component 202 and the correction detection component 203 to move along the scanning path, to control the drive component 201 to correct the scanning pose of the terahertz scanning component 202 according to the deviation, and to generate a digital twin model of the coating according to the terahertz time domain signal fed back by the terahertz scanning component 202 and the corresponding spatial position information.

[0025] Using the coating inspection system provided in this embodiment, the following coating inspection methods can achieve accurate inspection of the coating quality on the surface of the component under test 204, such as... Figure 2 As shown, the coating detection method specifically includes the following steps: S202 obtains the scanning path of the coating by the terahertz scanning component 202.

[0026] The component under test 204 includes a substrate and a coating applied to the surface of the substrate. The control component stores a three-dimensional geometric model of the substrate, such as a turbine blade, or a CAD model. The control component generates a drive component 201 based on the three-dimensional geometric model of the substrate to drive the terahertz scanning component 202 to scan the coating. Specifically, the coating detection system is located in a spatial coordinate system. The scanning path includes multiple sequentially arranged scanning points that cover the entire area of ​​the coating. The drive component 201 has corresponding coordinates (x, y, z, Rx, Ry, Rz) for each scanning point. The terahertz scanning module can detect the corresponding sampling point of the coating at each scanning point. Specifically, the sequentially arranged scanning points can be arranged at equal intervals.

[0027] S204 controls the terahertz scanning component 202 to sequentially reach each scanning point according to the scanning path for scanning. When the terahertz scanning component 202 reaches each scanning point, it first obtains the deviation between the current scanning pose of the terahertz scanning component 202 and the target scanning pose of the corresponding acquisition point of the coating. Based on the deviation, it determines the pose correction amount and applies it to the terahertz scanning component 202. Then, it controls the terahertz scanning component 202 to scan the corresponding acquisition point to obtain the terahertz time domain signal.

[0028] The driving component 201 drives the terahertz scanning component 202 and the correction detection component 203 to move synchronously, sequentially reaching each scanning point for detection. Specifically, when the terahertz scanning component 202 and the correction detection component 203 reach the target scanning point, the correction detection component 203 first detects the scanning pose of the terahertz scanning component 202 when scanning the corresponding target sampling point in the coating at the target scanning point as the current scanning pose. The current scanning pose is fed back to the control component, which then uses the current scanning pose in conjunction with the terahertz scanning component 202's ability to accurately detect the target. The target scanning pose of the sampling point is compared, and the deviation between the two is calculated. Based on the magnitude of the deviation, it is determined whether the scanning pose of the terahertz scanning component 202 needs to be corrected. Specifically, the pose correction amount is determined based on the deviation, and the driving component 201 is controlled to drive the terahertz scanning component 202 to perform the corresponding pose correction, so that the corrected terahertz scanning component 202 can accurately detect the target sampling point, thereby accurately obtaining the terahertz time domain signal of the target sampling point; specifically, the terahertz time domain signal is the terahertz waveform signal within the continuous detection time.

[0029] Subsequently, the driving component 201 continues to drive the terahertz scanning component 202 and the correction and detection component 203 to move along the scanning path to the next target scanning point. By correcting the scanning pose of the terahertz scanning component 202, the terahertz time-domain signal of the next target sampling point is accurately detected. In this way, based on the theoretical scanning path, the operation of actual detection and correction followed by actual detection at each scanning point ensures the detection accuracy of the terahertz scanning component 202 at each scanning point, and correspondingly obtains a terahertz time-domain signal with high accuracy at each sampling point.

[0030] S206 calculates the physical characteristic data of the coating based on the terahertz time-domain signal of each scanning point. The physical characteristic data includes at least the coating thickness.

[0031] After the terahertz scanning component 202 performs pose correction at each scanning point, it can obtain the spatial position information of the scan point and sampling point after pose correction, i.e., the spatial position coordinates, based on the driving amount of the driving component 201 in the x, y, z, Rx, Ry, and Rz directions. At the same time, after the terahertz scanning component 202 performs pose correction at each scanning point, it detects the corresponding sampling point of the coating to obtain a terahertz time-domain signal with high accuracy. Both the spatial position coordinates and the terahertz time-domain signal are fed back to the control component. The control component can analyze the terahertz time-domain signal corresponding to each scanning point through signal processing and machine learning algorithms to calculate the physical feature data of the corresponding sampling point of the coating, such as the coating thickness at that sampling point.

[0032] S208 generates a digital twin model of the coating based on the mapping relationship between the physical feature data of each scanning point and the corresponding spatial location information.

[0033] The physical feature data at each scanning point is correlated with the corresponding spatial location information to form a mapping relationship between the two. Based on the mapping relationship, a digital twin model with the same size and geometry as the actual coating is generated at a 1:1 scale, and the digital twin model has high accuracy. Based on the digital twin model, the coating thickness and other physical feature data of each region of the coating can be obtained with high accuracy, and the coating quality can be accurately characterized based on the physical feature data.

[0034] The coating detection system provided in this embodiment, through the coating detection method described above, can detect the current scanning pose of the terahertz scanning component 202 at each scanning point based on the theoretical scanning path, by correcting the detection component 203 at each scanning point. Based on the deviation between the current scanning pose and the target scanning pose, the scanning pose of the terahertz scanning component 202 is corrected. That is, by first actual detection and correction, and then actual detection, the terahertz scanning component 202 can accurately detect the actual sampling points of the coating at each scanning point, overcoming signal attenuation and pose deviation caused by complex curved surfaces. This results in a highly accurate terahertz time-domain signal for each sampling point. Furthermore, based on the mapping relationship between the accurate terahertz time-domain signal at each sampling point and the accurate spatial position information after correction, a digital twin model that accurately characterizes the physical features of the coating is obtained, thereby accurately characterizing the coating quality and achieving accurate detection of the coating quality.

[0035] Specifically, the control component can use an iterative nearest-point algorithm to register the corrected spatial coordinate information of multiple sampling points with the digital twin model of the component under test 204, thereby mapping the determined physical features of the coating onto the digital twin model.

[0036] In this embodiment, the correction detection component 203 includes a laser triangulation sensor or a trinocular vision measurement system; the scanning pose includes the scanning incident angle and the scanning incident distance.

[0037] Taking a laser triangulation sensor as an example, when the driving component 201 drives the terahertz scanning component 202 and the correction detection component 203 to move along the scanning path to each scanning point, the laser triangulation sensor can detect in real time the actual distance between the scanning end of the terahertz scanning component 202 and the sampling point on the coating surface along the terahertz wave propagation direction. This actual distance is used as the current scanning incident distance of the current scanning pose. It also detects the actual angle between the scanning end of the terahertz scanning component 202 and the normal vector n at the sampling point on the coating surface along the terahertz wave propagation direction. This actual angle is used as the current scanning incident angle of the current scanning pose.

[0038] The target scanning pose includes the target scanning incident distance and the target scanning incident angle, which can accurately detect the sampling point. The target scanning incident distance is the focal plane distance of the terahertz scanning component 202. When the current scanning incident distance is the target scanning incident distance, the light spot emitted by the terahertz scanning component 202 onto the coating is minimized and the energy density is maximized, resulting in the highest accuracy of the terahertz time-domain signal at the sampling point. The scanning incident angle in the direction of the normal vector n at the coating sampling point is defined as 0°. When the target scanning incident angle is 0°, that is, when the extension direction of the terahertz wave emitted by the terahertz scanning component 202 is collinear with the normal vector, the terahertz wave is perpendicular to the sampling point. The optical path, reflection energy, and interface echo phase of the terahertz wave incident on the coating are more accurate, resulting in the highest accuracy of the terahertz time-domain signal at the sampling point.

[0039] The current scanning incident distance is compared with the target scanning incident distance, and the distance deviation between the two is calculated. The current scanning incident angle is compared with the target scanning incident angle, and the angle deviation between the two is calculated. When the distance deviation is less than or equal to a preset distance deviation value, and the angle deviation is less than or equal to a preset angle offset value, it indicates that the accuracy of the terahertz time-domain signal obtained by the current scanning pose sampling point of the terahertz scanning component 202 is high. At this time, no correction is required, the pose correction amount is determined to be 0, and the terahertz scanning component 202 is controlled to detect the sampling point to obtain the corresponding terahertz time-domain signal. When the distance deviation is greater than the preset distance deviation value, or the angle deviation is greater than the preset angle offset value, the accuracy of the terahertz time-domain signal obtained by the current scanning pose sampling point of the terahertz scanning component 202 is high. When the distance deviation is greater than the preset angle offset value, the accuracy of the terahertz time-domain signal obtained from the scanning sampling point of the current scanning pose of the terahertz scanning component 202 is low, and its scanning pose needs to be corrected. Based on the distance deviation value, angle deviation value and the current spatial position coordinates of the terahertz scanning component 202, the corresponding pose correction amount is determined, and the drive component 201 is controlled to correct the scanning pose of the terahertz scanning component 202 accordingly, so that the corrected distance deviation value and angle deviation value of the terahertz scanning component 202 meet the requirements. Finally, the terahertz scanning component 202 is controlled to detect the sampling point to obtain the corresponding terahertz time-domain signal.

[0040] Specifically, in this embodiment, step S204, which determines the pose correction amount based on the deviation amount and applies it to the terahertz scanning component 202, includes: determining whether the deviation amount is within a preset deviation range; if yes, determining that the pose correction amount is zero and controlling the terahertz scanning component 202 to maintain the current scanning pose; if no, using the inverse of the deviation amount as the pose correction amount, and correcting the scanning pose of the terahertz scanning component 202 based on the pose correction amount, so that the corrected scanning pose of the terahertz scanning component 202 is the target scanning pose.

[0041] When the distance deviation value is within the preset distance deviation range (i.e., the distance deviation value is less than or equal to the upper limit of the preset distance deviation range (preset distance deviation value)); and the angle deviation value is within the preset angle deviation range (i.e., the angle deviation value is less than or equal to the upper limit of the preset angle deviation range (preset angle offset value)), the accuracy of the terahertz time domain signal obtained by the current scanning pose sampling point of the terahertz scanning component 202 is high, and no correction is required. The pose correction amount is determined to be 0, and the terahertz scanning component 202 is controlled to detect the sampling point to obtain the corresponding terahertz time domain signal, thereby reducing the correction frequency of the terahertz scanning component 202 while ensuring detection accuracy.

[0042] When the distance deviation value is outside the preset distance deviation range (i.e., the distance deviation value is greater than the upper limit of the preset distance deviation range (preset distance deviation value)); or when the angle deviation value is outside the preset angle deviation range (i.e., the angle deviation value is greater than the upper limit of the preset angle deviation range (preset angle offset value), it indicates that the accuracy of the terahertz time-domain signal obtained from the scanning sampling point of the current scanning pose of the terahertz scanning component 202 is low, and its scanning pose needs to be corrected. Accordingly, the distance deviation values ​​(Δx, Δy, Δz) are adjusted accordingly. The inverse values ​​(-Δx, -Δy, -Δz) are used as distance correction values, and the inverse values ​​(-ΔRx, -ΔRy, -ΔRz) of the angle deviation values ​​(ΔRx, ΔRy, ΔRz) are used as angle correction values. The difference between the current spatial position coordinates of the terahertz scanning component 202 and the above-mentioned distance correction values ​​and angle correction values ​​is used as the corrected scanning pose coordinates. The corrected scanning pose is the target scanning pose. Then, the terahertz scanning component 202 is controlled to detect sampling points to obtain the corresponding terahertz time domain signal with the highest accuracy.

[0043] In this embodiment, the data measured by the correction detection component 203 can be smoothed by Kalman filtering; the angular deviation between the incident direction of the terahertz beam and the local normal vector of the sampling point is controlled within ±1%.

[0044] In this embodiment, the terahertz scanning component 202 includes a femtosecond laser and a photoconductive antenna for generating and detecting terahertz pulses. The detection method is reflection detection, specifically a reflection terahertz time-domain spectral system, wherein the effective spectral width is 0.1-5THz, the signal-to-noise ratio is 60-200dB, the femtosecond laser pulse width is 80-120fs, and the repetition frequency is 80-100MHz.

[0045] In this embodiment, when the physical characteristic data is the coating thickness, step S206, which calculates the physical characteristic data of the coating based on the terahertz time-domain signal at each scanning point, includes: obtaining the time delay of the two reflection peaks at the upper and lower interfaces of the coating in the terahertz time-domain signal; obtaining the refractive index of the coating; and calculating the coating thickness according to the following formula: ; In the formula, d is the coating thickness in meters (m); c is the speed of light of terahertz waves in a vacuum in meters per second (m / s). ν represents the time delay between the two reflection peaks at the upper and lower interfaces of the coating, in seconds; n is the refractive index of the coating, dimensionless.

[0046] Figure 7 In the coating detection method provided in this embodiment of the invention, the relationship between the echo amplitude and flight time obtained by the terahertz scanning component 202 emitting terahertz waves at the scanning point to the coating is shown in the figure. Figure 7 As shown, the coating is a thermal barrier coating, which consists of a ceramic layer, a thermally grown oxide (TGO) layer, and a binder layer from top to bottom. The pulse generated by the femtosecond laser in the terahertz detection module is split into a pump beam and a probe beam. The pump beam excites the terahertz emitter to generate a broadband terahertz pulse, which is then irradiated onto the coating surface. The probe beam forms a time scan in the optical delay unit, reconstructing the complete time-domain waveform through interaction with the returned terahertz signal. Specifically, when the terahertz wave reaches the interface between the air and the ceramic layer, the first echo peak F1 is obtained. When the terahertz wave reaches the interface between the ceramic layer and the TGO layer after refraction, the second echo peak F2 is obtained. When the terahertz wave reaches the interface between the TGO layer and the binder layer after refraction, the third echo peak F3 is obtained. The coating thickness of the ceramic layer at the sampling point can be calculated using the above formula based on the time delay Δt1 of F1 and F2. Similarly, the coating thickness of the TGO layer at the sampling point can be calculated using the above formula based on the time delay Δt2 of F2 and F3.

[0047] In this embodiment, the physical characteristic data also includes coating porosity, coating phase transition, TGO thickness, and internal layering of the coating at the sampling points. Specifically, when the coating has a multilayer structure, the interfaces between each layer can be calculated. Furthermore, based on the waveform characteristics of the terahertz time-domain signal at the sampling points, such as pulse broadening and energy attenuation, the coating porosity, TGO thickness, and coating phase transition can be calculated.

[0048] In this embodiment, the digital twin model is displayed as a color heatmap based on the mapping relationship between physical feature data and spatial location information to generate a 3D rendering visualization model. Different colors are displayed at corresponding locations in the digital twin model according to the magnitude of the physical feature data at each sampling point of the coating, thus obtaining a 3D rendering visualization model of the physical feature data. This model can be displayed through the imaging module of the control component, allowing users to conveniently view the physical feature data of various regions of the coating through the 3D rendering visualization model.

[0049] Specifically, through visualization and analysis of the control components, the updated digital twin model is presented in a three-dimensional rendering manner. The identified defects are graphically annotated and details can be queried. A color thermal map is generated based on the coating thickness to display the surface thickness distribution. It supports arbitrary cross-section cutting to view the internal layering of the coating and the TGO thickness change, and supports comparative analysis of data from multiple detection cycles.

[0050] Specifically, the 3D rendering visualization model supports arbitrary cross-section cutting to view the internal layering of the coating and the changes in TGO thickness.

[0051] In this embodiment, the control component can store multiple sets of coating physical characteristic data acquired over time, forming a spatiotemporal historical dataset; based on the spatiotemporal historical dataset, a coating lifespan model is trained; and using the coating lifespan model, the coating lifespan is predicted. Specifically, by utilizing real-time spatial mapping technology of physical characteristic data and CAD models, a high-fidelity digital twin of the thermal barrier coating is constructed. This not only realizes the spatial visualization distribution of coating quality but also, through continuous evolutionary analysis of the spatiotemporal historical dataset, achieves a leap from single-point detection to coating peeling failure prediction and remaining lifespan assessment, greatly improving the operation and maintenance efficiency of key components.

[0052] Specifically, the coating detection method also includes coating lifespan model determination and experimental calculation. The coating lifespan model determination includes the following steps: obtaining digital twin models of multiple coating samples at different lifespan test stages throughout their entire lifespan and forming a historical dataset; training the mapping relationship between the physical feature data of the coating samples and the remaining lifespan of the coating samples in the digital twin model based on the historical dataset, and generating the coating lifespan model.

[0053] The coating detection method provided in this embodiment is used to detect multiple coating samples. Based on the physical feature data of the obtained digital twin model, a historical database of the entire coating life cycle is established. This database covers the evolution data of the physical features of the coating at different life test stages, including but not limited to features such as coating thickness, porosity, and TGO changes. Subsequently, the above historical data is used as a training set to train a machine learning model (such as a regression analysis model, random forest algorithm, or LSTM long short-term memory network) to learn the mapping relationship between the physical features of the coating and the remaining service life, thereby generating a coating service life model.

[0054] The actual calculation includes the following steps: obtaining a digital twin model of the coating; substituting the physical characteristic data in the digital twin model of the coating into the coating service life model, and outputting the remaining service life of the coating.

[0055] In actual testing, the physical feature data in the terahertz time domain signal measured by the coating detection method provided in this embodiment are input into the trained coating lifespan model. The coating lifespan model outputs the current coating lifespan prediction value, thereby realizing the prediction of the coating lifespan.

[0056] The coating inspection system and method provided in this embodiment realize the interactive closed loop of physical inspection and virtual model, providing reliable technical support for the full life cycle management and digital quality tracking of industrial coatings.

[0057] In this embodiment, the drive component 201 may include a six-axis robotic arm with an end effector, and the coating detection system may also include a turntable 205 and a PC terminal 206 (Personal Computer). The turntable 205 is used to load the component to be tested 204 with a coating on its surface. The PC serves as a control component for calculation, judgment, control, and image display. The control component may specifically include a central processing unit module and an imaging module.

[0058] Both the terahertz scanning component 202 and the correction and detection component 203 are fixed to the end effector, and the part under test 204 is mounted on the turntable 205. In use, the turntable 205 can drive the part under test 204 to rotate at a speed between 5 and 15 rpm. The six-axis robotic arm can drive the terahertz scanning component 202 and the correction and detection component 203 to scan and detect the coating on the surface of the part under test 204 according to the scanning path in conjunction with the turntable 205. The spatial position information includes the driving position information of the six-axis robotic arm and the rotation angle information of the turntable 205. The turntable 205 can achieve 720° rotation. When the six-axis robotic arm is calibrating the tool, its repeatability is no more than 0.02 mm. The movement speed of the six-axis robotic arm during data acquisition is between 10 and 50 mm / s.

[0059] The coating inspection system and method provided in this embodiment integrate terahertz time-domain spectroscopy technology and a seven-axis linkage automation platform based on digital twins to achieve high-precision, non-contact, fully automated characterization of coating components with complex shapes. Real-time laser compensation effectively overcomes signal attenuation and attitude deviation caused by complex curved surfaces. The digital twin architecture enables the presentation of heat maps with real-time registration of physical inspection data and CAD models. Combined with a deep learning model, it achieves inspection visualization and provides quantitative support for preventive maintenance of key equipment, significantly improving inspection efficiency and service safety.

[0060] Figure 3 This is a second flowchart of the coating detection method provided in an embodiment of the present invention. Figure 3 As shown, the coating detection method includes: S302 generates a scanning path based on the three-dimensional geometric model of the substrate.

[0061] The S304 acquires terahertz time-domain signals and spatial location information.

[0062] The S306 extracts physical feature data based on terahertz time-domain signals.

[0063] S308 generates a digital twin model based on the mapping relationship between physical feature data and spatial location information.

[0064] The S310 visualizes physical properties on a digital twin model, resulting in a 3D rendered visualization model.

[0065] Figure 4 This is a third flowchart of the coating detection method provided in an embodiment of the present invention. Figure 4 As shown, the coating detection method includes: Start the signal detection system.

[0066] S401 acquires the scanning path and the target scanning incident distance and target scanning incident angle at each scanning point.

[0067] The S402 drives the terahertz scanning module to the scanning point.

[0068] The S403 acquires the current scanning incident distance and the current scanning incident angle through the correction detection component.

[0069] S404 calculates the distance deviation value based on the current scanning incident distance and the target scanning incident distance, and calculates the angle deviation value based on the current scanning incident angle and the target scanning incident angle.

[0070] S405 determines whether the following conditions are met: the distance deviation value is within a preset distance deviation range, and the angle deviation value is within a preset angle deviation range. If yes, proceed to step S406; otherwise, proceed to step S407.

[0071] The S406 controls the terahertz scanning component to detect sampling points and obtain the corresponding terahertz time-domain signal.

[0072] S407 determines the distance correction amount based on the distance deviation value, determines the angle correction amount based on the angle deviation value, and applies it to the terahertz scanning component. Return to step S403.

[0073] Figure 5 This is the fourth flowchart of the coating detection method provided in an embodiment of the present invention. Figure 5 As shown, the coating detection method includes: S501 acquires terahertz time-domain signals.

[0074] S502 performs preprocessing on terahertz time-domain signals.

[0075] S503 Physical feature extraction. Proceed to steps S504 and S506.

[0076] S504 extracts time-domain features: echo peak position and time delay Δt.

[0077] S505 Calculate the coating thickness. Proceed to step S509.

[0078] S506 extracts waveform features: pulse broadening and energy attenuation.

[0079] The S507 uses a multi-physical feature signal machine learning model to learn and train the extracted waveform features.

[0080] S508 calculates the TGO thickness, porosity, and phase transition. Proceed to step S509.

[0081] S509 obtains the physical feature dataset.

[0082] S510 generates digital twin models.

[0083] Figure 6 This is the fifth flowchart of the coating detection method provided in an embodiment of the present invention. Figure 6 As shown, the coating detection method includes: S601 collects physical characteristic data of the coating from multiple tests.

[0084] S602 constructs a historical dataset mapping the physical characteristics of the coating to its remaining useful life.

[0085] S603 training coating lifespan model.

[0086] S604 Input the physical characteristic data of the current coating.

[0087] The S605 coating lifespan model predicts the remaining lifespan of the coating.

[0088] S606 outputs the prediction results.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coating inspection system, characterized in that, include: Driver component (201); A terahertz scanning component (202) is disposed at the end of the driving component (201) and is used to scan the coating along the scanning path under the drive of the driving component (201); A correction detection component (203), disposed at the end of the driving component (201), is used to move synchronously with the terahertz scanning component (202) under the drive of the driving component (201) to detect the deviation of the current scanning pose of the coating and the target scanning pose of the terahertz scanning component (202) at each scanning point; and, A control component, connected to the drive component (201), the terahertz scanning component (202), and the correction detection component (203), is used to control the drive component (201) to drive the terahertz scanning component (202) and the correction detection component (203) to move along the scanning path, to control the drive component (201) to correct the scanning pose of the terahertz scanning component (202) according to the deviation amount, and to generate a digital twin model of the coating according to the feedback terahertz time domain signal and the corresponding spatial position information.

2. The coating inspection system according to claim 1, characterized in that, The correction detection component (203) includes a laser triangulation sensor or a trinocular vision measurement system.

3. The coating inspection system according to claim 1, characterized in that, The terahertz scanning component (202) includes a femtosecond laser and a photoconductive antenna, wherein the effective spectral width is 0.1-5THz, the signal-to-noise ratio is 60-200dB, the femtosecond laser pulse width is 80-120fs, and the repetition frequency is 80-100MHz.

4. A coating detection method, characterized in that, The coating inspection system according to any one of claims 1-3, wherein the coating inspection method comprises: Obtain the scanning path of the terahertz scanning component on the coating; The terahertz scanning component is controlled to sequentially reach each scanning point according to the scanning path. When the terahertz scanning component reaches each scanning point, it first obtains the deviation between the current scanning pose of the terahertz scanning component and the target scanning pose of the coating. Based on the deviation, a pose correction amount is determined and applied to the terahertz scanning component. Then, the terahertz scanning component is controlled to scan the coating to obtain the terahertz time domain signal. The physical characteristic data of the coating are calculated based on the terahertz time-domain signals obtained at each of the scanning points, and the physical characteristic data includes at least the coating thickness. A digital twin model of the coating is generated based on the mapping relationship between the physical feature data obtained at each scanning point and the corresponding spatial location information.

5. The coating detection method according to claim 4, characterized in that, The step of determining the pose correction amount based on the deviation amount and applying it to the terahertz scanning component includes: Determine whether the deviation is within a preset deviation range; If so, the pose correction amount is determined to be zero, and the terahertz scanning component is controlled to maintain the current scanning pose; If not, the inverse of the deviation amount is used as the pose correction amount, and the scanning pose of the terahertz scanning component is corrected according to the pose correction amount so that the corrected scanning pose of the terahertz scanning component is the target scanning pose.

6. The coating detection method according to claim 4, characterized in that, The scanning pose includes the scanning incident angle and the scanning incident distance.

7. The coating detection method according to claim 4, characterized in that, When the physical characteristic data is the coating thickness, the step of calculating the physical characteristic data of the coating based on the terahertz time-domain signal of each scanning point includes: The time delay of the two reflection peaks at the upper and lower interfaces of the coating in the terahertz time-domain signal is obtained; Obtain the refractive index of the coating; The coating thickness is calculated using the following formula: ； In the formula, d is the coating thickness in meters (m); c is the speed of light of terahertz waves in a vacuum in meters per second (m / s). ν represents the time delay between the two reflection peaks at the upper and lower interfaces of the coating, in seconds; n is the refractive index of the coating, dimensionless.

8. The coating detection method according to any one of claims 4-7, characterized in that, The physical characteristic data also include at least one of coating porosity and coating phase transition.

9. The coating detection method according to any one of claims 4-7, characterized in that, The digital twin model is displayed as a color heatmap based on the mapping relationship between physical feature data and spatial location information to generate a three-dimensional rendering visualization model.

10. The coating detection method according to any one of claims 4-7, characterized in that, The coating detection method further includes: Coating lifespan model determination: Obtain digital twin models of multiple coating samples at different life test stages throughout their entire life cycle, and form a historical dataset; Based on the historical dataset, the mapping relationship between the physical feature data of the coating samples and the remaining service life of the coating samples in the digital twin model is obtained through training, and a coating service life model is generated. Actual measurement and calculation: Obtain a digital twin model of the coating; Substitute the physical feature data from the digital twin model of the coating into the coating lifespan model to output the remaining lifespan of the coating.

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