Methods and systems for determining radar-compatible coatings

Abstract

A method and system for determining radar-compatible coatings are provided. In one example, the method includes acquiring a reflectance measurement of a target coating to characterize its color. One or more candidate formulations are generated to determine color matches with the target coating's color. A corresponding color and corresponding radar property are predicted for each of the one or more candidate formulations. A radar-compatible coating composition that is visually identical or substantially similar to the target coating is generated. The generation of the radar-compatible coating composition is at least in part based on the corresponding color and corresponding radar property of one of the one or more candidate formulations.

Description

Technical Field

[0001] The technical field generally relates to coatings, and more specifically to methods and systems for determining radar-compatible coatings, which can be applied, for example, to a component substrate to provide an aesthetic appearance while being substantially transparent to radar. Background Technology

[0002] In motor vehicles, radar is used to detect objects for various purposes, such as autonomous driving, adaptive cruise control, automatic braking, and other advanced driver assistance systems. Radar sensors are typically mounted behind components of the motor vehicle (usually bumpers or vehicle panels), thus obscuring the radar device. In this respect, the radar signal must penetrate the bumper as it travels toward the object to be detected, and then penetrate the bumper again as it is reflected back to the vehicle. The bumper, including any coating applied to its surface, may transmit, reflect, or absorb radar. Any reflection or absorption of the radar signal limits the effective detection range of the radar. For radar to be used for automatic braking, its effective range must be at least as far as the vehicle's braking distance at its travel speed.

[0003] If the component on which the radar is mounted (such as a bumper or vehicle panel) is metal, the radar's effective range is zero; therefore, the component used is typically plastic or other non-metallic materials. The component includes a substrate and usually also includes a coating covering the substrate. Motor vehicle coatings typically include a base coating, and usually also include a primer layer and / or a clear coat layer, with interfaces between each layer. Radars commonly used for object detection in motor vehicles are typically 77 GHz band radars, which describes a class of radars operating at frequencies of approximately 76 to 81 GHz (e.g., W-band).

[0004] Therefore, radar transmission through a typical bumper substrate and its coating is important for the effective operation of many vehicle radar systems. Furthermore, many vehicle exterior coatings or paint systems include components that provide the desired aesthetic appearance. For example, many coating systems use special effect components, such as metallic effect components, to enhance the aesthetic appearance of the paint. Unfortunately, some of these components can disrupt the functionality of the radar system when applied to component substrates such as, for example, plastic bumper substrates. This is because these components limit or impede radar transmission through the component panel by significantly reflecting and / or absorbing radar signals rather than being radar-compatible (e.g., not substantially transparent or transmissive to radar signals).

[0005] Therefore, it is desirable to provide methods and systems for determining radar-compatible coatings, which can be applied, for example, to a component substrate to provide an aesthetically pleasing appearance while being substantially transmissive to radar. Furthermore, other desirable features and characteristics of this disclosure will become apparent from the following detailed description and the appended claims, in conjunction with this background art. Summary of the Invention

[0006] This document provides a method and system for determining radar-compatible coatings. According to an exemplary embodiment, the method includes acquiring a reflectance measurement of a target coating to characterize its color. A processor is used to generate one or more candidate formulations to determine color matches with the target coating's color. Using the processor and one or more prediction models, a corresponding color and corresponding radar property of each of the one or more candidate formulations are predicted. The processor is used to generate a radar-compatible coating composition that is visually identical to or substantially similar in color to the target coating. The generation of the radar-compatible coating composition is at least in part based on the corresponding color and corresponding radar property of one of the one or more candidate formulations.

[0007] According to an exemplary embodiment, the system includes a computer device having a processor. The computer device is operable to acquire reflectance measurements of a target coating to characterize the color of the target coating. The processor generates one or more candidate formulations to determine color matches with the color of the target coating. Using the processor and one or more prediction models, a corresponding color and corresponding radar property of each of the one or more candidate formulations are predicted. The processor generates a radar-compatible coating composition that is visually identical or substantially similar in color to the target coating. The radar-compatible coating composition is generated at least in part based on the corresponding color and corresponding radar property of one of the one or more candidate formulations. Attached Figure Description

[0008] Various embodiments will now be described with reference to the following figures, wherein the same numbers denote the same elements, and wherein:

[0009] Figure 1 A block diagram of a method for determining a radar-compatible coating according to an exemplary embodiment is shown;

[0010] Figure 2 This is a diagram illustrating the predicted values ​​of the permittivity responses of candidate formulation coatings and radar-compatible coatings for evaluating radar properties, according to an exemplary embodiment.

[0011] Figure 3 (A) is a graph of the reflectance of the candidate formulation coating and the radar-compatible coating at 15° relative to the wavelength index according to an exemplary embodiment, to characterize color similarity and / or color matching;

[0012] Figure 3 (B) is a graph of the reflectance of the candidate formulation coating and the radar-compatible coating at 45° relative to the wavelength index according to an exemplary embodiment, to characterize color similarity and / or color matching;

[0013] Figure 3 (C) is a graph of the reflectance of the candidate formulation coating and the radar-compatible coating at 110° relative to the wavelength index according to an exemplary embodiment, to characterize color similarity and / or color matching; and

[0014] Figure 4 A perspective view of a system for determining a radar-compatible coating according to an exemplary embodiment is shown. Detailed Implementation

[0015] The following detailed description is exemplary in nature only and is not intended to limit the various embodiments or their application and use. Furthermore, it is not intended to be bound by any theories set forth in the foregoing background or the following detailed description.

[0016] As used herein, a "component" of a vehicle includes a plastic or polymer substrate with an overcoating. As used herein, the term "overcoating" means that the overcoating material is physically in contact with the underlying substrate, or that the overcoating material is physically separated from the underlying substrate by an intermediate material, such as an overcoating clear coat separated from the underlying substrate by a base coating. It should be understood that components can rotate or move, and therefore reference to one component overcoating another refers to a specific orientation; it should be understood that the actual component can rotate to different orientations. As used herein, the term "vehicle" refers to a motorized vehicle, such as a car, truck, aircraft, or other device propelled through space by an electric motor or engine. The term "vehicle" includes vehicles propelled by an electric motor powered by burning fuel, and vehicles propelled by an electric motor. The overcoating of a component includes one or more of a primer, a base coating, and a clear coat.

[0017] Various embodiments envisioned herein relate to methods and systems for determining radar-compatible coatings, which may be applied, for example, to a component substrate to provide an aesthetic appearance while being substantially transmissive to radar. As used herein, the term "radar-compatible" should be understood to mean substantially transparent or transmissive to radar signals, with relatively low (e.g., radar signal loss less than about 20%, or 1 dB) or no transmission loss of radar signals when traveling through a specified medium.

[0018] The exemplary embodiments taught herein provide a method comprising: acquiring a reflectance measurement of a target coating to characterize the color of the target coating; generating one or more candidate formulations to determine a color match with the color of the target coating; using one or more prediction models to predict a corresponding color and a corresponding radar property for each of the one or more candidate formulations; generating a radar-compatible coating composition that is visually identical to or substantially similar in color to the target coating. The radar-compatible coating composition is generated at least in part based on the corresponding color and corresponding radar property of one of the selected candidate formulations.

[0019] In an exemplary embodiment, advantageously, by generating a radar-compatible coating composition based on the corresponding color and corresponding radar properties of a selected candidate formulation, the corresponding component composition of the selected candidate formulation can be effectively improved to minimize color difference of the corresponding color, while altering or constraining the corresponding radar properties to enhance the radar transparency or transmittance of the radar-compatible coating composition.

[0020] refer to Figure 1 A method 10 for determining a radar-compatible coating is provided according to an exemplary embodiment. In the exemplary embodiment, as will be discussed in further detail below, method 10 is a computational method executed via a computer device including a processor.

[0021] Method 10 includes acquiring (step 12) a reflectance measurement of the target coating to characterize the color of the target coating. In one embodiment, the reflectance measurement of the target coating is acquired, for example, by retrieving reflectance measurements from a database containing multiple existing reflectance measurements of various target coatings. In another embodiment, the reflectance measurement of the target coating is acquired from real-time measurements of the target coating using reflectance measurement devices known in the art, such as handheld commercial spectrophotometers like the BYK-mac I, X-Rite MA-T12, or Axalta's Acquire Quantum EFX, or research-grade spectrophotometers such as the Perkin-Elmer LAMBDA series spectrophotometers.

[0022] In an exemplary embodiment, method 10 includes using a processor to generate (step 14) one or more candidate formulations for forming a coating to determine color matching with the color of the target coating. As is known to those skilled in the art, color matching quality can be quantified by various metrics, such as the sum of squares of the differences between the target and candidate reflectance spectra at multiple illumination and detection angles, or the average CIE94 color difference between the target and candidate colors at multiple illumination and detection angles. In an exemplary embodiment, one or more candidate formulations are obtained via brute-force search, a genetic algorithm, or alternatively, a software-implemented expert system. In a brute-force search, all possible formulations are thoroughly evaluated by testing all combinations of components from a given coating system. In a genetic algorithm, as is known to those skilled in the art, a candidate population is generated and algorithmically treated similarly to gene mixing (crossover, mutation, etc.). In a software-implemented expert system, heuristic algorithms are used to reduce the search space and computation time for generating candidate formulations; for example, starting with a radar-incompatible target formulation, radar-compatible candidates are generated by replacing highly radar-incompatible components with radar-compatible components that have extremely similar color performance.

[0023] Each candidate formulation comprises a corresponding component composition. For example, each candidate formulation may include one or more types of resins (such as acrylic resins, epoxy resins, polyurethane resins, etc.), various additives, accelerators, curing agents, water-based and / or solvent-based carriers that flash out during the drying or curing process of the coating composition, colorant, or pigment (such as effect pigment flakes, interference flakes, colored pigments). In one embodiment, various candidate formulations (e.g., novel or non-existent formulations) can be developed from scratch, in which case, for example, optimization algorithms generally available to those skilled in the art can be used to fine-tune or optimize (step 16) the component concentrations in the respective component compositions of one or more candidate formulations to improve color matching with the color of the target coating.

[0024] In an exemplary embodiment, the radar-incompatible formulation may already exist. In this case, by using a color prediction model known to those skilled in the art, a radar-compatible alternative to the highly radar-incompatible component in the formulation can be found, and a software-implemented expert system can generate radar-compatible candidate formulations extremely quickly.

[0025] In an exemplary embodiment, method 10 further includes using a processor and one or more prediction models 18 and 20 to predict (step 22) the corresponding color and corresponding radar attribute of each of one or more candidate formulations. In the exemplary embodiment, two prediction models 18 and 20 are used, a first prediction model 18 being configured to predict the corresponding color of each of one or more candidate formulations, and a second prediction model 20 being configured to predict the radar attribute of each of one or more candidate formulations. Prediction models configured to predict candidate formulation colors are well known in the industry. A non-limiting example of prediction model 18 for predicting candidate formulation colors is described in U.S. Patent No. 7,466,415, filed May 6, 2004, which claims priority to Provisional Patent Application No. 60 / 468,595, filed May 7, 2003, owned by the assignee of this application and the entire contents of which are incorporated herein by reference for all purposes. A non-limiting example of a prediction model 20 for predicting radar properties (such as radar transmission properties, e.g., composition, coating formulation, and / or the dielectric constant response of the coating formed according to the coating formulation) is described in U.S. Patent Application No. 16 / 951,342, filed November 18, 2020, owned by the assignee of this application, the entire contents of which are incorporated herein by reference for all purposes. In an exemplary embodiment, prediction model 20 predicts the corresponding radar properties of each candidate formulation by evaluating the corresponding coating dielectric constant for each candidate formulation.

[0026] In an exemplary embodiment, method 10 further includes using a processor to generate (step 24) a radar-compatible coating composition that is visually identical or substantially similar in color to the target coating. The radar-compatible coating composition can be generated entirely based on the corresponding color and corresponding radar properties of a selected candidate formulation. Alternatively, the radar-compatible coating composition can be generated at least in part based on the corresponding color and corresponding radar properties of a selected candidate formulation. For example, the radar-compatible coating composition can be generated based on color, gloss, and corresponding radar properties. In this case, the color and gloss of the radar-compatible coating are visually identical or substantially similar to the target coating. Alternatively, the radar-compatible coating composition can be generated based on color and radar properties. In this case, the color of the radar-compatible coating is visually identical or substantially similar to the target coating.

[0027] In an exemplary embodiment, the radar-compatible coating composition is visually identical or substantially similar in color to the target coating. In an exemplary embodiment, the selected candidate formulation is color-matched to the target coating, for example, characterized by reflectance measurements obtained at various angles. For example, the color match between the selected candidate formulation and the target coating can be characterized by reflectance measurements obtained at a 45° incident angle using signal detection occurring at various aspecular angles (typically from about -15° to about 110°).

[0028] In addition, refer to Figure 3 In an exemplary embodiment, a radar-compatible coating composition substantially similar in appearance to the target coating is indirectly generated by color matching the radar-compatible coating composition with the color and optional gloss of a selected candidate formulation. As shown, line 30 represents a reflectance measurement of the selected candidate formulation, and line 32 represents a reflectance measurement of the radar-compatible coating, wherein the sample is illuminated at a 45° angle relative to the normal in the range of 400 nm to 700 nm, and measurements are taken at inverse directional reflection angles of 15°, 45°, and 110°. Lines 30 and 32 are overlapped to demonstrate the similarity of the reflectance spectra. In this example, the color matching metric is used on an arbitrary scale, where a color matching metric below 2 is considered a very good match, and a color matching metric of 0 is a perfect color match. The dielectric constant of the target formulation is also able to reach 25, while the dielectric constant of the initial radar-incompatible formulation is approximately 50.

[0029] refer to Figures 1 to 2 In an exemplary embodiment, the radar property is a radar transmission property, such as dielectric constant response or coating dielectric constant. Furthermore, in an exemplary embodiment, generating (step 24) the radar-compatible coating composition includes estimating the coating dielectric constant 26 of the initial composition using the prediction model 20 as described above. The corresponding coating dielectric constant 28 of a selected candidate formulation is estimated during the generation (step 24) of the radar-compatible coating composition, or an estimate is used based on the prediction (step 22) of the corresponding radar properties of each candidate formulation. The coating dielectric constant 26 of the initial coating composition is compared with the corresponding radar-optimized coating dielectric constant 28 of a selected candidate formulation.

[0030] like Figure 2As shown, for example, in automotive radar bands including frequencies from approximately 76 to approximately 81 GHz, the coating dielectric constant 26 of the initial coating composition and the corresponding radar-optimized coating dielectric constant 28 of a selected candidate formulation are estimated and compared. In one example, the coating dielectric constant 26 and the corresponding coating dielectric constant 28 are compared with each other at discrete frequencies, such as 76.5 GHz, 77 GHz, and 81 GHz. In the example shown, the coating dielectric constant 26 of the initial coating composition has a coating dielectric constant of approximately 40 at 77 GHz, which is significantly higher than the corresponding radar-optimized coating dielectric constant 28 of the selected candidate formulation (which has a coating dielectric constant of approximately 25 at 77 GHz). The coating dielectric constant 28 of approximately 25 for the radar-compatible coating composition is approximately -0.5 dB on a unidirectional transmission scale, meaning that approximately 90% of radar transmission passes through the coating, while the corresponding coating dielectric constant 26 of approximately 40 for the selected candidate formulation is approximately -1.5 dB on a unidirectional transmission scale, meaning that approximately 70% of radar transmission passes through the coating. Therefore, the radar transmittance of the radar-compatible coating composition is significantly higher than that of a selected candidate formulation, which will be discussed in further detail below. The selected candidate formulation is the initial formulation basis for the modification to generate the radar-compatible coating composition.

[0031] refer to Figure 1 In an exemplary embodiment, generating (step 24) a radar-compatible coating includes using a processor to improve the corresponding component composition of a selected candidate formulation to minimize the color difference of the corresponding color of the selected candidate formulation, while modifying or constraining the corresponding radar properties to enhance the radar compatibility of the radar-compatible coating composition. In one embodiment, a constrained optimization algorithm is used to perform the improvement of the corresponding component composition of the selected candidate formulation. In an exemplary embodiment, the software implementation of the algorithm uses a color prediction model to adjust the concentration of formulation components to minimize the color difference with the target coating, while also using a radar or dielectric constant prediction model to estimate the dielectric constant of the formulation, and the minimization of the color difference is constrained by the dielectric constant (e.g., requiring the total dielectric constant of the formulation to be below 25 or 20).

[0032] In an exemplary embodiment, the composition of a selected candidate formulation is improved by modifying one or more components, and / or changing the concentration of the components, using one or more other components, to minimize color difference and enhance the radar compatibility of the radar-compatible coating composition. In an exemplary embodiment, the dielectric constant response is defined as the dielectric constant of a candidate component as a function of the concentration of the candidate component in the candidate formulation. In one example, the selected candidate formulation comprises a first component having a first dielectric constant response, and the first component is modified, entirely or partially, using a second component having a second dielectric constant response less than the first dielectric constant response. In an exemplary embodiment, the first dielectric constant response of the first component is higher than a predetermined threshold dielectric constant response, while the second dielectric constant response of the second component is equal to or lower than the predetermined threshold dielectric constant response. In an exemplary embodiment, the predetermined threshold dielectric constant response is approximately 25 at 77 GHz. In another embodiment, the predetermined threshold dielectric constant response is approximately 10 at 77 GHz.

[0033] In an exemplary embodiment, the first component provides the selected candidate formulation with an appearance or color effect that is the same as or similar to that of the second component in the radar-compatible coating composition. In one example, the first and second components are different flake components, such as an aluminum flake component and a pearlescent flake component, respectively.

[0034] refer to Figure 4 The computer 100 can be used as an apparatus for implementing the techniques and methods described herein. The computer 100 may include input devices 112 such as a keyboard 114, a mouse 116, electronic communication devices such as a modem, or various other communication devices. The input devices 112 communicate with the computer's processor 118 (processing unit) and / or memory 120, wherein the processor 118 and memory 120 communicate with each other. Various embodiments of the processor 118 and memory 120 are known to those skilled in the art. The computer 100 also includes an output device 122, such as the monitor shown. Other exemplary embodiments of the output device 122 include a modem, a printer, or other components known to those skilled in the art. The methods and techniques described above can be implemented on the computer 100.

[0035] Computer-readable medium 124 contains a computer program that instructs a computer to implement the methods and techniques described above. The computer-readable medium may be an SD card, USB storage medium, floppy disk, CD-ROM, DVD, hard disk, or other means that can be read by a computer and includes a memory for storing the computer program. In some embodiments, the computer program may be downloaded electronically to the computer, but the downloaded computer program is stored on a tangible device somewhere.

[0036] In an exemplary embodiment, the computer program instructs a computer to request input from input device 112, wherein the requested input relates to acquiring a reflectance measurement of the target coating to characterize the color of the target coating. The computer program instructs processor 118 to generate one or more candidate formulations to determine color matches with the target coating, wherein processor 118 may access one or more mathematical / predictive models, algorithms (e.g., genetic algorithms), or software-implemented expert systems to generate candidate formulations. The computer program instructs processor 118 to access one or more predictive models or otherwise collaborate with one or more predictive models to predict the corresponding color and corresponding radar properties of each of the one or more candidate formulations. Simultaneously or subsequently, the computer program instructs processor 118 to generate a radar-compatible coating composition that is visually identical or substantially similar in color to the target coating, based at least in part on the corresponding color and corresponding radar properties of a selected candidate formulation. The computer program instructs output device 122 to present the radar-compatible coating composition, including its associated color and radar properties, and / or any other information as described above.

[0037] Although at least one exemplary embodiment has been presented in the foregoing detailed description of this disclosure, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiments or multiple exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing exemplary embodiments of this disclosure. It should be understood that various changes may be made to the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of this disclosure as set forth in the appended claims.

Claims

1. A method for determining radar-compatible coatings, the method comprising the following steps: Obtain a reflectance measurement of the target coating to characterize the color of the target coating; The processor generates one or more candidate formulations to determine color matching with the color of the target coating; Using the processor and one or more prediction models, predict the corresponding color and corresponding radar attribute of each of the one or more candidate recipes; as well as The processor is used to generate a radar-compatible coating composition that is visually identical or substantially similar to the target coating, including the color, wherein the generation of the radar-compatible coating composition is at least in part based on the corresponding color and the corresponding radar property of one or more candidate formulations.

2. The method of claim 1, wherein each of the one or more candidate formulations comprises a corresponding component composition, and wherein generating the radar-compatible coating comprises: The processor is used to improve the corresponding ingredient composition of one of the candidate formulations to minimize the color difference of the corresponding color of the one of the candidate formulations, while altering or constraining the corresponding radar properties to enhance the radar compatibility of the radar-compatible coating composition.

3. The method of claim 2, wherein the improvement comprises further improving the corresponding ingredient composition of one of the candidate formulations using a constrained optimization algorithm.

4. The method of claim 2, wherein generating the one or more candidate formulations further comprises optimizing the concentration of an ingredient in the corresponding component composition of one of the candidate formulations using the processor and optimization algorithm after improvement, to further improve color matching with the color of the target coating.

5. The method of claim 2, wherein improving the corresponding component composition of one of the candidate formulations comprises completely or partially altering one or more of the components using one or more other components, and / or altering the concentration of the components, to minimize the color difference and enhance the radar compatibility of the radar-compatible coating composition.

6. The method of claim 5, wherein the component of one of the candidate formulations comprises a first component having a first dielectric constant response, and wherein improving the component of one of the candidate formulations comprises completely or partially altering the first component using a second component having a second dielectric constant response less than the first dielectric constant response.

7. The method of claim 6, wherein the first dielectric constant response of the first component is higher than a predetermined threshold dielectric constant response, and the second dielectric constant response of the second component is equal to or lower than the predetermined threshold dielectric constant response.

8. The method of claim 7, wherein the predetermined threshold dielectric constant response is 25 at 77 GHz.

9. The method of claim 1, wherein predicting the corresponding radar property of each of the one or more candidate formulations comprises estimating the corresponding coating dielectric constant of each of the one or more candidate formulations.

10. The method of claim 9, wherein generating the radar-compatible coating composition comprises: Estimate the dielectric constant of the radar-compatible coating composition; Estimate the dielectric constant of the coating of one of the one or more candidate formulations or use an estimate of the dielectric constant of the coating of one of the one or more candidate formulations; as well as The dielectric constant of the radar-compatible coating composition is compared with the dielectric constant of the corresponding coating of one of the one or more candidate formulations.

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