Patent Application
20250208065
This disclosure relates generally to apparatus, systems and methods of characterizing a solid sample using a sensor that operates in the radio or microwave frequency range of the electromagnetic spectrum. For example, the techniques described herein can be used to analyze structures associated with aerial vehicles.
A number of products exist that detect or otherwise characterize solid materials. For example, X-ray fluorescence sensors and commercially-available metal detectors are known that can detect some characteristics of homogenous and heterogeneous solids using electromagnetic (EM) radiation in their extremely high and low frequency bands, respectively. The ionizing nature of X-ray radiation may make it unsuitable for everyday civilian use. In addition, nuclear quadrupole resonance (NQR) sensors provide a method of finding the EM resonance of a solid constituent, and the sensors used in NQR typically require a cylindrical or conical physical sample structure to be placed in a coil.
A solid constituent sensor or sensor system is described herein that uses signals in the radio frequency/microwave frequency range. The solid constituent sensor and methods described herein use one or more radio or microwave frequency signals transmitted to and/or into a solid sample to aid in making a determination about the solid sample. This is generally referred to as characterizing a solid sample. Characterizing the solid sample can include, but is not limited to: detecting one or more constituents in the solid sample; detecting the lack of one or more constituents in the solid sample; determining the molecular makeup or chemical composition of homogenous or heterogeneous solid constituents; determining whether the solid sample has an expected chemical composition; determining whether the solid sample deviates from an expected chemical composition; determining whether the solid sample has certain types of structures, microstructures or defects; identifying the solid sample; and others.
A solid constituent sensor or sensor system described herein can include at least one transmit antenna and at least one receive antenna. The at least one transmit antenna is positioned and arranged to transmit a transmit signal to and/or into a solid sample, and the at least one receive antenna is positioned and arranged to detect a response resulting from transmission of the transmit signal by the at least one transmit antenna to and/or into the solid sample. A transmit circuit is electrically connectable to the at least one transmit antenna, and the transmit circuit is configured to generate the transmit signal in a radio or microwave frequency range of an electromagnetic spectrum. A receive circuit is electrically connectable to the at least one receive antenna, and the receive circuit is configured to receive the response detected by the at least one receive antenna. A processor in communication with the receive circuit is configured to execute instructions to characterize the solid sample based on the detected response.
In operation, the signal detected by the receive antenna that results from transmitting the signal by the transmit antenna can be analyzed (e.g., processed and/or compared with at least one reference signal) to make a determination about the solid sample. The comparison can take many forms. For example, the comparison can be whether the detected signal matches the reference signal. For example, the comparison can be whether the detected signal deviates from the reference signal, for example by a predetermined amount.
A solid constituent characterization method can include transmitting a transmit signal from a transmit antenna to and/or into a solid sample, where the transmit signal is in a radio frequency (RF) or microwave frequency range of the electromagnetic spectrum. A response signal that results from transmission of the transmit signal to and/or into the solid sample is detected at a receive antenna. The detected response signal (or a derivative thereof) is then used to characterize the solid sample.
In one example application, the sensor system described herein can be used to analyze structures associated with air vehicles and spacecraft, collectively referred to as aerial vehicles. For example, the sensor system can be used to analyze an aerial vehicle structure to detect metal fatigue, micro-cracks, thermal stress, defects, deformations, and other possible indicators of overstress and/or failure. The aerial vehicle structures that can be analyzed are any structures associated with or used on an air vehicle or a spacecraft, whether propelled by one or more turbine engines or by one or more propellers, one or more rocket engines or any other form of propulsion. Air vehicles include, but are not limited to, manned or unmanned military and commercial aircraft, private aircraft, helicopters, gliders, missiles, unmanned air vehicles, and others. Spacecraft includes, but are not limited to, manned and unmanned man-made devices intended for operation beyond the Earth's atmosphere as well as the launch vehicles therefore, including satellites. Examples of aerial vehicle structures that can be analyzed include, but are not limited to, at least a portion of a wing, at least a portion of a fuselage, a turbine blade, a turbine blade root, a turbine disc, a compressor blade, a stator blade, a propeller blade, an aileron, an elevator, a rudder, a winglet, a trim tab, a flap, a spoiler, an air brake, a slat, a nozzle throat or exit nozzle/cone or motor case of a rocket engine, and the like.
The following is a detailed description of apparatus, systems and methods of characterizing a solid sample via spectroscopic techniques using frequencies in the radio or microwave frequency bands of the electromagnetic spectrum. A solid constituent sensor described herein includes at least one antenna which functions as a transmit antenna to transmit an electromagnetic signal in the radio or microwave frequency range to and/or into a solid sample and at least one antenna which functions as a receive antenna that receives/detects an electromagnetic signal in the radio or microwave frequency range resulting from transmission of the electromagnetic signal to and/or into the solid sample. The signal(s) detected by the receive antenna(s) is then used to characterize the solid sample, for example by comparing the detected signal or a derivative thereof to one or more stored reference signals.
Based on the characterization, a notification/warning/alert signal can be generated and transmitted to a notification/warning/alert device. The notification/warning/alert signal can inform a user the identify or status of the detected solid sample, or alert a user to a problem with the solid sample. The notification/warning/alert signal can alert a user that the solid constituent material is as expected, and therefore the solid sample including the solid constituent material is at an expected status. The notification/warning/alert signal can notify or alert a user that the solid sample is trending over time toward a potential problem. The notification/warning/alert signal can alert a user that the solid sample has been stable (i.e., not changing or changing within a predetermined range) over a time period. The notification/warning/alert signal device can generate a visual notice, such as a light or text on a display screen, an audible notice, a haptic notice, or the like.
Examples of sensors that can detect constituents using radio frequency or microwave frequency signals are described in U.S. Pat. Nos. 10,548,503, 11,063,373, 11,058,331, 11,033,208, 11,284,819, 11,284,820, 10,548,503, 11,234,619, 11,031,970, 11,223,383, 11,058,317, 11,193,923, 11,234,618, 11,389,091, U.S. 2021/0259571, U.S. 2022/0077918, U.S. 2022/0071527, U.S. 2022/0074870, U.S. 2022/0151553, each of which is incorporated herein by reference in its entirety.
As referenced herein, a “solid sample” may refer to a physical portion or specimen of a solid material that can be analyzed or characterized for its structures, chemical compositions, characteristics, properties (e.g., physical/chemical/mechanical/electrical properties), identification of the sample, etc. Example solid samples described herein may include, but are not limited to, metals (e.g., irons), alloys (e.g., iron compounds), minerals, polymers, ceramics, etc. For example, an iron compound sample can be analyzed or characterized to determine the carbon content thereof, which may be used to determine a number of related physical properties of the iron compound including, for example, brittleness, hardness, corrosion-resistance, etc.
As referenced herein, an “constituent” or “constituents” contained in a solid sample can be any constituent that one may wish to detect. The constituents may vary widely depending on the type of solid sample and/or the analytical and characterization objectives. In an example, for a solid metal or metal alloy sample (e.g., an iron compound), suitable constituents may include, but are not limited to, a chemical composition such as a carbon content, an impurity, a trace element, a structure, a defect, a microstructure, a water content, a water-induced corrosion product, etc. In another example, for a solid concrete sample, suitable constituents may include, but are not limited to, various concrete constituents such as a cement content, an aggregate (e.g., a sand, a gravel, a crushed stone, etc.), an admixture (e.g., a chemical additive such as an accelerator, retarder, a superplasticizer, etc.), an air-entraining agent, an air void, a reinforcing material, a cementitious material, a moisture content, etc. In yet another example, for a soil sample, suitable constituents may include, but are not limited to, various soil constituents such as a moisture content, a nutrient (e.g., nitrogen, phosphorus, potassium, etc.), a particular type of cations (i.e., positively charged ions), an organic matter content, a salt content, a soil texture (e.g., proportions of sand, silt, and clay), a heavy metal (e.g., lead, cadmium, etc.), a contaminant (e.g., a pesticide, a pollutant, etc.), a microbial population, a biological activity, a mineral composition, a particle size distribution, etc. In yet another example, for a plant sample, suitable constituents may include, but are not limited to, a chemical composition such as plant-specific compounds (e.g., alkaloids, flavonoids, terpenoids, etc.), secondary metabolites (e.g., tannins, phenolics, etc.), nutrients (e.g., nitrogen, phosphorus, potassium, etc.), a mineral content, a tissue structure, a water content, etc.
As referenced herein, “homogeneous solid constituent” or “heterogeneous solid constituent” may refer to the uniformity or non-uniformity of the composition and/or properties within a solid sample regarding one or more constituents to be detected. In a homogeneous solid sample, the composition and properties of a constituent may be substantially consistent and uniform throughout the entire sample. In a heterogeneous solid sample, there may be regions or phases with distinct compositions, structures, or properties. For example, a granite rock can be a heterogeneous solid sample since it may include different minerals at different regions.
Referring now to
The transmit antenna 11 is positioned, arranged and configured to transmit a signal 21 that is the radio frequency (RF) or microwave frequency range of the electromagnetic spectrum to or into a surface 71 of the solid sample 7. The transmit antenna 11 can be an electrode or any other suitable transmitter of electromagnetic signals in the radio frequency (RF) or microwave frequency range. The transmit antenna 11 can have any arrangement and orientation relative to the solid sample 7 that is sufficient to allow the sample sensing, detecting, or characterization to take place. In one non-limiting embodiment, the transmit antenna 11 can be arranged to face in a direction that is substantially toward the surface 71 of the solid sample 7.
In an embodiment, the sensor system 5 or a portion of the sensor system 5 can be located exterior of the solid sample 7 during sample characterization. For example, the transmit antenna 11 and the receive antenna 13 may be located exterior of the solid sample 7 and in proximity to the surface 71. In an embodiment, the sensor system 5 or a portion of the sensor system 5 may be located inside the solid sample 7 during sample characterization. For example, the transmit antenna 11 and the receive antenna 13 may be located within a hollow space or cavity of the solid sample 7 and in proximity to an internal surface of the solid sample 7. In an embodiment, a portion of the sensor system 5 (e.g., the transmit antenna 11 and the receive antenna 13) can be mounted to a housing (e.g., a probe head) which is configured to accommodate the antennas and provide mechanical support and protection. The probe head may insert into a solid sample (e.g., a soil sample) during sample characterization.
In an embodiment, a coupling medium or mechanism may be provided between the transmit and receive antennas 11, 13 and the solid sample 7 to facilitate the transfer of radio frequency (RF) or microwave frequency energy between the sensor system 5 and the solid sample 7. The coupling medium may include, but is not limited to, a dielectric material, a matching fluid, a waveguide, or the like. The coupling medium or mechanism may be flexible and have any suitable configurations.
The signal 21 transmitted by the transmit antenna 11 is generated by the transmit circuit 15 which is electrically connectable to the transmit antenna 11. The transmit circuit 15 can have any configuration that is suitable to generate a transmit signal to be transmitted by the transmit antenna 11. Transmit circuits for generating transmit signals in the RF or microwave frequency range are well known in the art. In an embodiment, the transmit circuit 15 can include, for example, a connection to a power source, a frequency generator, and optionally filters, amplifiers, frequency control mechanisms, or any other suitable elements for a circuit generating an RF or microwave frequency electromagnetic signal. In an embodiment, the signal generated by the transmit circuit 15 can have a frequency that is in the range from about 10 kHz to about 100 GHz. In another embodiment, the frequency can be in a range from about 300 MHz to about 6000 MHz. In another embodiment, the frequency range can be from about 10 kHz to about 10 GHz. In an embodiment, the transmit circuit 15 can be configured to sweep through a range of frequencies that are within the range of about 10 kHz to about 100 GHz, or in another embodiment a range of about 300 MHz to about 6000 MHz.
In the embodiment depicted in
In an embodiment, the transmit antenna 11 may be controlled to switch between multiple sets of antenna(s) to handle the different levels of increased power boosted by the power module 152. For example, the transmit antenna 11 may be controlled to switch between a first set of antenna(s) corresponding to the first level of boosted power, and a second set of antenna(s) corresponding to the second, higher level of boosted power.
In an embodiment, the transmit signal 21 may be adjusted, via one or more of the transmit circuit 15, the power module 152, and the transmit antenna 11, to adjust a penetration depth d into the solid sample 7. For example, the power module 152 may be controlled to boost the power of the transmit signal 21 to increase the penetration depth d. The transmit circuit 15 may be controlled to adjust the frequency of the transmit signal 21 to adjust the penetration depth d. It is to be understood that the depth of penetration into different solid materials may depend on various factors, including, for example, the signal frequency, the solid material properties, the signal wavelength/frequency, the signal power, etc. For example, the penetration depth may vary from a few micrometers, to a few millimeters, to a few centimeters, or to a few meters, depending on the solid material properties. In an embodiment, the penetration depth is less than one centimeter. The controller 19 may control the respective parts of the sensor system 5 to adjust the penetration depth suitable for desired applications. In another embodiment, the penetration depth d may be close to zero (e.g., a few micrometers or less, or a few nanometers or less) in which case the solid sample is characterized based on a signal reflected back from the surface 71.
The receive antenna 13 is positioned, arranged, and configured to detect one or more electromagnetic response signals 23 that result from the transmission of the transmit signal 21 by the transmit antenna 11 to and/or into the solid sample 7 and impinging on the constituent 9 or a local area including the constituent 9. The receive antenna 13 can be an electrode or any other suitable receiver of electromagnetic signals in the radio frequency (RF) or microwave range. In an embodiment, the receive antenna 13 is configured to detect an electromagnetic signal having a frequency that is in the range from about 10 kHz to about 100 GHz, or in another embodiment a range from about 300 MHz to about 6000 MHz. In another embodiment, the frequency can be in a range from about 10 kHz to about 10 GHz. The receive antenna 13 can have any arrangement and orientation relative to the solid sample 7 that is sufficient to allow detection of the response signal(s) 23 to allow the characterization to take place. In one non-limiting embodiment, the receive antenna 13 can be arranged to face in a direction that is substantially toward the surface 71 of the solid sample 7.
The receive circuit 17 is electrically connectable to the receive antenna 13 to convert the electromagnetic energy detected by the receive antenna 13 into one or more signals reflective of the response detected by the receive antenna 13. The receive circuit 17 can have any configuration that is suitable for interfacing with the receive antenna 13 to convert the electromagnetic energy detected by the receive antenna 13 into one or more signals reflective of the response signal(s) 23. The construction of receive circuits are well known in the art. The receive circuit 17 can be configured to condition the signal(s) prior to providing the signal(s) to the controller 19, for example through amplifying the signal(s), filtering the signal(s), or the like. Accordingly, the receive circuit 17 may include filters, amplifiers, or any other suitable components for conditioning the signal(s) provided to the controller 19. Further information on a transmit circuit and a receive circuit in an analyte sensor is disclosed in U.S. Pat. No. 11,063,373 the entire contents of which are incorporated herein by reference.
In an embodiment, the receive circuit 17 may include an analog to digital (AD) converter to convert the signal detected by the receive circuit 17 from an analog signal into a digital processor readable format. The AD converter may be separate from the receive circuit 17 or the AD converter may be considered part of the receive circuit 17. Similarly, a digital to analog converter, which may be part of or separate from the transmit circuit 15, converts a digital signal into an analog signal for transmission by the transmit antenna 11.
The controller 19 controls operation of the sensor system 5, including controlling the transmit circuit 15 and the receive circuit 17. The controller 19 may include a processor, also known as a central processing unit (CPU), which may facilitate the operation of the sensor system 5 according to instructions stored in memory 12. The processor may include suitable logic, circuitry, interfaces, and/or code that may be configured to execute a set of instructions stored in the memory 12. The processor may be a hardware component that performs arithmetic, logic, and control operations on data. The processor may be comprised of the arithmetic logic unit, control unit, memory subsystems, and other subsystems. The processor may be responsible for performing signal procession and/or comparison, as well as arithmetic and logical operations on data. The processor may include components for addition, subtraction, multiplication, and division and logical operations such as AND, OR, and NOT. The processor may be responsible for fetching instructions from the memory 12, decoding them, and executing them. The processor may manage the flow of data between different components of the solid constituent sensor as a whole, ensuring that operations are performed in the correct order, and that data is transferred efficiently. The processor may provide fast access to frequently used data and instructions. The processor may include components such as caches, registers, and pipelines, which are designed to minimize the time required to access and manipulate data. The processor may include various other components and subsystems, such as instruction set architecture (ISA), which may define the set of instructions that the processor can execute. The processor may specify the format of instructions and data, the addressing modes used to access memory 12 and I/O devices, and the interrupt and exception handling mechanisms used to manage errors and other events. The processor may include advanced instruction execution capabilities, support for virtualization and parallel processing, and power management mechanisms that reduce energy consumption and heat dissipation. In some embodiments, the controller 19 may be a microcontroller, programmable logic controller (PLCs), or digital signal processors (DSPs) and may be implemented as software components running on general-purpose computers or embedded systems.
A signal storage 14 stores one or more reference signals. The signal storage 14 may be any form of storage that is suitable for storing signals of reference solid samples for use in analyzing (e.g., comparing) the signal detected by the receive antenna 13 to detect and characterize the solid sample. For example, the signal storage 14 may store a database containing signal data related to the reference signals obtained from reference solid samples. The signals may present in any suitable forms, such as, for example, waveforms, spectroscopy diagrams (e.g., spectroscopy lines), frequency spectrum, time-domain signals, amplitude and/or phase signals, imaging signals, modulated signals, etc. The signal storage 14 may be part of the memory 12 or may be at a location separate from the memory 12.
The reference signals stored in the signal storage 14 can be retrieved by, e.g., the processor of the controller 19, and used to analyze the response signal detected by the receive circuit 17. In an embodiment, one or both of the response signal from the receive circuit 17 and the reference signal retrieved from the signal storage 14 can be processed by the controller 19 and transformed to any suitable format that can be compared to each other.
For example, the controller 19 can perform a signal waveform comparison between the signal from the receive circuit 17 and the reference signal to detect or characterize the solid sample 7. The techniques for comparison of signal waveforms are well-known in the art. The signal waveform comparison may be to match the detected signal waveform with the stored reference signal(s) 36 (see
In one embodiment, the controller 19 may optionally be in communication with at least one external device 25 such as a user device and/or a remote server 27, for example through one or more wireless connections such as Bluetooth, wireless data connections such a 4G, 5G, LTE or the like, or Wi-Fi. If provided, the external device 25 and/or remote server 27 may process (or further process) the signals that the controller 19 receives from the receive circuit 17, for example to characterize the solid sample 7. If provided, the external device 25 may be used to provide communication between the sensor system 5 and the remote server 27, for example using a wired data connection or via a wireless data connection or Wi-Fi of the external device 25 to provide the connection to the remote server 27.
With continued reference to
In an embodiment, any one or more of the antennas 34a, 34b, 36a, 36b can be connected to the transmit circuit 15 whereby any one or more of the antennas 34a, 34b, 36a, 36b can function as a transmit antenna. In addition, any one or more of the antennas 34a, 34b, 36a, 36b can be connected to the receive circuit 17 whereby any one or more of the antennas 34a, 34b, 36a, 36b can function as a receive antenna to detect a response that results from transmitting the transmit signal to and/or into the solid sample. Controlling any of a number of antennas to transmit an RF signal and any of a number of antennas to receive an RF signal is disclosed in U.S. patent Ser. Nos. 11/058,331, 11/193,923, and 11/330,997 each one of which is incorporated herein by reference in its entirety.
The embodiment depicted in
Referring again to
The receive antenna 13 can have any form suitable for receiving RF/microwave signals from the solid sample as a result of transmitting the transmit signal by the at least one transmit antenna to and/or into the solid sample. For example, the receive antenna 13 can include a strip or patch of conductive material such as metal or other material that can receive signals in the radio or microwave frequency range of the electromagnetic spectrum. The receive antenna 13 may reside on the surface of a substrate or plate, the receive antenna 13 may partially protrude from (i.e. be partially embedded within) the substrate or plate, or the receive antenna 13 may be completely embedded within the substrate or plate as depicted in
One or both of the antennas 11, 13 may be position adjustable in order to alter the relative position/orientation between the antennas 11, 13, between the transmit antenna 11 and the object surface 71, and between the receive antenna 13 and the object surface 71. For example, the substrate(s) for one or both of the antennas 11, 13 can be mounted to a movable/rotatable mechanism to adjust the relative position/orientation of the antennas 11, 13. Alternatively, the antennas 12, 14 may be position adjustable while keeping the plates 16, 18 stationary. Changing the relative position/orientation between the antennas 11, 13 may change the sensing performance of the solid constituent sensor system 5. In an embodiment, the angles and/or shapes of the antennas 11, 13 may be changed in order to alter the performance of the sensor system 5. An example of an RF constituent sensor with adjustable transmit and/or receive components is disclosed in U.S. Pat. No. 11,696,698, the entire contents of which are incorporated by reference.
The reference signals 36 may be stored in a database in the signal storage 14. The database may include one or more database tables, of which every column of a database table represents a particular variable or field, and each row/column of the database table may correspond to a given record of the database. The database tables may list values for each of the variables, and/or for each record of the dataset. Various signal forms of various solid samples can be stored and organized in the database tables.
Referring again to
Referring to
At block 52 (Transmit RF/microwave signal into solid sample), a transmit signal that is in a radio or microwave frequency range of the electromagnetic spectrum is transmitted from the transmit antenna to and/or into the solid sample. The transmit signal may be a single discrete signal or the signal may be part of a frequency sweep in which multiple signals are transmitted. The frequency sweep may start at an initial frequency and end at a final frequency, with the signals separated by equal or unequal frequency steps. An example of performing frequency sweeps in a radio/microwave frequency sensor is disclosed in U.S. Pat. No. 11,033,208, the entire contents of which are incorporated herein by reference. Processing may proceed from block 52 to block 54.
At block 54 (Detect response from the solid sample), a response is detected at the receive antenna. The response results from transmission of the transmit signal to and/or into the solid sample. The transmitted signal may interact with the solid sample and constituents thereof as it transmits to and/or into the solid sample. The interaction may alter the transmit signal and generate one or more electromagnetic response signals which can be detected by the receive antenna 13 and used to characterize the solid sample. Processing may proceed from block 54 to block 56.
At block 56 (Characterize the solid sample based on the response), the detected response is then used to characterize the solid sample. For example, the detected signal waveform may, in its original form or after being converted to other suitable forms by a processor of the sensor system 5, be compared to one or more stored reference signals as described above for
In an embodiment, the detected signal may be compared to a single reference signal. When the detected signal deviates from the reference signal, the sensor system 5 can determine that the detected solid sample deviates from an expected chemical composition, and a notification/alarm signal can be sent, for example to an alarm, to notify a user of a related problem of the detected solid sample. The detected signal may need to deviate from the stored signal by a predetermined amount, such as 10% or more, 5% or more, 3% or more, or other quantifiable amount in order to generate a notification signal. The deviation of the detected signal from the stored reference signal can indicate a number of problems such as metal fatigue. The detected signal may also match the reference signal which can indicate that the solid sample has an expected chemical composition and can be used for material identification.
In another embodiment, the detected signal may be compared to multiple reference signals in an effort to look for a match between the detected signal and one of the reference signals. A match can indicate that the solid sample is acceptable or has an expected chemical composition, structure, or property, or a match can indicate that the solid sample is not acceptable or may not have an expected chemical composition, structure, or property.
The solid constituent sensors 5 described herein may form or be incorporated into residential, industrial and/or commercial sensors/detectors. Examples of sensors that the solid constituent sensor 10 can be incorporated into include, but are not limited to, a metal detector, an infrastructure detector, an aerial vehicle parts detector, a soil detector, a plant detector, and many others.
In an embodiment, a metal detector may include one or more of the solid constituent sensors described herein. The one or more of the solid constituent sensors can detect one or more constituents in a solid metallic material and characterize the solid metallic material based on the detected constituents, including, for example, determining metal fatigue, water saturation, metal identification, etc. For example, metal identification can be determined using a chemical composition analysis based on the detected one or more constituents in the solid metallic material sample. The detected signal can be compared to one or more stored reference signals of known standards or reference databases to determine its identify. In an embodiment, metal fatigue can be assessed by analyzing the one or more detected constituents (e.g., by comparing to the stored reference signal(s)) to determine crystallographic defects, microstructure changes, and mechanical properties (e.g., hardness, brittleness, etc.) of the solid metallic material. In an embodiment, the one or more of the solid constituent sensors can also examine the presence or absence of water molecules or water-induced corrosion products (e.g., iron oxides, chlorides, sulfides, etc.) based on the detected signal and the stored reference signal(s).
In an embodiment, an infrastructure detector may include one or more of the solid constituent sensors described herein. The one or more of the solid constituent sensors can detect one or more constituents in a solid material of an infrastructure structure (e.g., a bridge part, a building part) and characterize the solid material based on the detected constituents.
In an embodiment, an aircraft parts detector may include one or more of the solid constituent sensors described herein. The one or more of the solid constituent sensors can detect one or more constituents in a solid material of an aircraft part (e.g., wings, fuselages, turbine blades, etc.) and characterize the solid material based on the detected constituents.
In an embodiment, a ship parts detector may include one or more of the solid constituent sensors described herein. The one or more of the solid constituent sensors can detect one or more constituents in a solid material of a ship part (e.g., hulls, propellers, etc.) and characterize the solid material based on the detected constituents.
In an embodiment, a soil detector may include one or more of the solid constituent sensors described herein. The one or more of the solid constituent sensors can detect one or more constituents in the soil and characterize the soil based on the detected constituents.
In an embodiment, a plant detector may include one or more of the solid constituent sensors described herein. The one or more of the solid constituent sensors can detect one or more constituents in plant and characterize/identify the plant based on the detected constituents.
In one example application the sensor system described herein, the sensor system can be used to analyze a structure of an aerial vehicle (e.g. an air vehicle or a spacecraft). The aerial vehicle structure that can be analyzed is any structure associated with or used on an aerial vehicle, whether propelled by one or more turbine engines, by one or more propellers, by one or more rocket engines, or any other form or propulsion. Aerial vehicles include air vehicles such as, but not limited to, manned and unmanned military and commercial aircraft, private aircraft, helicopters, gliders, missiles, unmanned aerial vehicles, and others. Aerial vehicles further include spacecraft such as, but not limited to, manned and unmanned man-made devices intended for operation beyond the Earth's atmosphere as well as the launch vehicles therefore, including satellites. The sensor system can be used to analyze an aerial vehicle structure to detect metal fatigue, micro-cracks, thermal stress, defects, deformations, and other possible indicators of overstress and/or failure. Examples of aerial vehicle structures that can be analyzed include, but are not limited to, at least a portion of a wing, at least a portion of a fuselage, a turbine blade, a turbine blade root, a turbine disc, a compressor blade, a stator blade, a propeller blade, an aileron, an elevator, a rudder, a winglet, a trim tab, a flap, a spoiler, an air brake, a slat, a nozzle throat or exit nozzle/cone or motor case of a rocket engine, and the like. The structure being analyzed may be a metal (a pure metal or an alloy), a metallic composite, or a non-metal such as plastic or a non-metallic composite. The structure may be rigid or non-rigid. The structure may be a structural component of the aerial vehicle or a non-structural component of the aerial vehicle.
The analysis using the sensor system can take place with the aerial vehicle structure in its usual location on the aerial vehicle without having to remove the structure from the aerial vehicle. Alternatively, the structure can be removed from the aerial vehicle prior to the analysis by the sensor system.
The detected response signal(s) is then converted from an analog signal into a digital processor readable (i.e. a digital signal) format by an AD converter. The converted digital signal (or a portion thereof) may then be compared to one or more stored signals, which are stored in a suitable storage location such as a database, to make a determination about the aerial vehicle structure 60. In another embodiment, the detected response signal(s) is not converted into a digital processor readable format, and the detected response signal(s) in analog form is compared to one or more stored signals also in analog form.
In one embodiment, the stored signals may be signals indicative of an acceptable aerial vehicle structure. The stored signals can be generated by using the sensor system 5 (or a similar sensor system) to scan one or more known acceptable aerial vehicle structures a number of times over a range of frequencies (i.e. a frequency sweep), and saving the individual detected signals at each frequency or compiling the detected signals at each frequency into a composite average signal for that frequency. If the converted signal matches one of the stored signals, that can indicate that the structure 60 is in acceptable condition and can continue to be used. The signals may match identically or may be considered to match if they vary from one another by some predetermined acceptable tolerance difference, for example 5%, 10%, or the like.
In another embodiment, the stored signals may be signals indicative of an unacceptable aerial vehicle structure. The stored signals can be generated by using the sensor system 5 (or a similar sensor system) to scan one or more known unacceptable aerial vehicle structures a number of times over a range of frequencies (i.e. a frequency sweep), and saving the individual detected signals at each frequency or compiling the detected signals at each frequency into a composite average signal for that frequency. If the converted signal matches one of the stored signals, that can indicate that the structure 60 is in an unacceptable condition and cannot continue to be used. The signals may match identically or may be considered to match if they vary from one another by some predetermined acceptable tolerance difference, for example 5%, 10%, or the like.
In generating the stored signals and in conducting an analysis of the aerial vehicle structure 60, the sensor system can generate RF signals that can range from just over 300 MHz to just over 4000 MHz. There is a transmit (Tx) amplifier to boost the signal, and then the RF signal may be routed through a switch matrix that allows for it to be sent to any one of four antenna elements to be transmitted, for example as described in U.S. Pat. No. 11,058,331 which is incorporated herein by reference in its entirety. In this example, the antenna elements may be spaced 20 mm apart from one another. The antenna elements may be mounted in a structure of milled stainless steel shielding to reduce RF interference from materials other than the structure 60. The same switch matrix may also establish the receive (Rx) path, where one of the four antenna elements is chosen to detect/receive the signal that results from the transmitted signal. Once through the switch matrix, the signal may be amplified with a low noise amplifier (LNA) to set it in the appropriate range of the power measurement circuitry, which translates the received RF signal's power into a voltage output that can be sampled by an analog to digital converter. The voltage output at each frequency depends on the dielectric properties of the aerial vehicle structure. Combining that information across thousands of frequencies provides the aerial vehicle structure's 60 unique spectral response.
Initially, a training dataset may be generated. Each aerial vehicle structure to be analyzed may be scanned a number of times, for example 60 times, using a protocol that includes locating the sensor system and the aerial vehicle structure in proximity to or in direct contact with one another, and running one or a plurality of frequency sweeps across a frequency range, for example the 300 MHz-4000 MHz range, with a predetermined frequency step, for example in 1 MHz steps. The aerial vehicle structures used to generate the training datasets can be, as discussed above, acceptable aerial vehicle structures (i.e. aerial vehicle structures that are considered acceptable for continued operation), or unacceptable aerial vehicle structures (i.e. aerial vehicle structures that are considered unacceptable for continued operation), or combinations of acceptable and unacceptable structures. Each aerial vehicle structure may be “sweeped” by the sensor system a plurality of time, for example six times, with each frequency sweep consisting of a plurality of frequencies. The resulting detected observations can then be used to train the model. After the model is trained, the aerial vehicle structure 60 can then be analyzed.
Data analysis may be carried out using any suitable machine learning data analysis tool. A non-limiting example includes Python with one or more of the following packages: numPy, pandas, matplotlib, and scikit-learn. Analyzing data using machine learning tools is well known in the art.
The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
