Fault isolation sensor system and method

Abstract

The present disclosure generally relates to a fault isolation sensor system for determining whether a potential fault is more likely to be on the rotor side or on the stator side. The measurement signal is transmitted from the rotor antenna to the stator antenna, and then from the stator antenna to the controller. The controller is configured to monitor the measurement signal. If the measurement signal is outside a predetermined range or exceeds a predetermined threshold, the stator antenna may be interrogated with an interrogation signal, with the reflected signal compared to the interrogation signal and the ratio of the reflected signal to the interrogation signal being used to identify a potential side of the fault.

Description

Technical Field

[0001] The present application is generally directed to fault isolation systems and methods and, in particular, to such systems and methods for use with aircraft engines. Background Art

[0002] Aircraft engines, such as internal combustion aircraft engines, include rotating components characterized by rotating shafts. Sensors can be used to monitor and measure certain characteristics of rotating shafts within the engine to assess the performance and / or health of the engine. For example, monitoring characteristics such as torque, temperature, rotational speed, and strain of the shaft can enable early detection of suboptimal performance and / or components requiring maintenance.

[0003] Monitoring one or more characteristics of a rotating shaft of a rotating assembly typically requires mounting one or more discrete sensors on or near the shaft. The signals generated by the one or more sensors can be remotely communicated to a processing unit (such as a controller) that is spaced apart from the shaft for analyzing the signals to determine the measured characteristics. In one example, a shaft antenna is disposed on the rotating shaft and a stator antenna is disposed on an adjacent stator. An RF sensor is mounted on the shaft and is configured to generate a measurement signal when the shaft rotates relative to the stator. The stator antenna receives the measurement signal from the RF sensor via the shaft antenna. A controller operably connected to the stator antenna can be configured to detect the measurement signal.

[0004] If there is an anomaly in the measurement signal detected by the controller, the controller may indicate a fault. However, the measurement signal does not indicate which component or side (e.g., rotor or stator) is the potential cause of the fault. This may undesirably lead to potential inspection and repair of components that are unlikely to be the source of the fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Various needs are met, at least in part, by providing a fault isolation sensor system and associated method for an aircraft engine as described in the following detailed description, particularly when studied in conjunction with the accompanying drawings. A complete and enabling disclosure of the various aspects of the specification, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, wherein:

[0006] Figure 1 is a schematic diagram of a fault isolation sensor system coupled to a shaft of a rotor assembly according to an embodiment;

[0007] Figure 2 shows a schematic cross-sectional perspective view of a fault isolation sensor system in combination with a rotor assembly according to an embodiment;

[0008] Figure 3 is a block diagram of a fault isolation sensor system according to an embodiment;

[0009] Figure 4 is a diagram of a voltage standing wave ratio circuit (VSWRC) for use with an embodiment of a fault isolation sensor system;

[0010] Figure 5 is a schematic cross-sectional view of an aircraft engine according to an embodiment; and

[0011] Figure 6 is a flow chart of a method of isolating a fault on an aircraft engine using a fault isolation sensor system.

[0012] The elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size and / or relative position of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the various embodiments of the present teaching. In addition, common but well-understood elements that are useful or necessary in commercially feasible embodiments are generally not described to facilitate less obstructed observation of these different embodiments of the present teaching. Certain actions and / or steps may be described or depicted in a specific order of occurrence, but those skilled in the art will understand that such specificity regarding sequence is not actually required. DETAILED DESCRIPTION

[0013] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter references to refer to features in the drawings. Like or similar reference numbers in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0014] Except where different specific meanings have been set forth herein, the terms and expressions used herein have the ordinary technical meanings given to these terms and expressions by those skilled in the art in the above technical field. Unless otherwise specifically indicated, the word "or" used herein should be interpreted as having a disjunctive structure, not a conjunction structure. Unless otherwise specified herein, the terms "connect", "fix", "attach to", etc. refer to both direct connection, fixation or attachment, and indirect connection, fixation or attachment through one or more intermediate components or features.

[0015] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0016] The term "at least one" in a context such as "at least one of A, B, and C" means only A, only B, only C, or any combination of A, B, and C.

[0017] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, for a gas turbine engine, front refers to a position closer to the engine inlet, while rear refers to a position closer to the engine nozzle or exhaust.

[0018] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0019] Approximate language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that may be permissibly varied without resulting in a change in the basic function to which it is related. Thus, values ​​modified by terms such as "about," "approximately," and "substantially" are not limited to the precise values ​​specified. In at least some cases, approximate language may correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximate language may refer to within a 10% margin.

[0020] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, such ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0021] As used herein, the term "proximate" means closer to one side or one end than to the opposite side or one end.

[0022] It should be understood that the controller 112 provided herein can implement the various functions described herein. According to the hardware architecture, such a controller 112 may include but is not limited to a processor 113, a memory 117, and one or more input and / or output (I / O) device interfaces connected via a local interface 119 communication. The local interface may include, for example, but not limited to, one or more buses and / or other wired or wireless connections. The processor may be a hardware device for executing software (particularly software stored in a memory). The processor may be a custom or commercial processor, a central processing unit (CPU), an auxiliary processor in several processors associated with a computing device, a semiconductor-based microprocessor (in the form of a microchip or chipset), or any device generally used to execute software instructions.

[0023] The memory devices described herein (e.g., memory devices of controller 112) may include any one or a combination of volatile memory elements (e.g., random access memory (RAM), such as dynamic RAM (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), video RAM (VRAM), etc.) and / or non-volatile memory elements (e.g., read-only memory (ROM), hard drive, tape, CD-ROM, etc.). In addition, the memory may include electronic, magnetic, optical, and / or other types of storage media. The memory may also have a distributed architecture in which various components are located away from each other but can be accessed by the processor.

[0024] The controller 112 may implement the functions described herein in any combination of hardware and software (e.g., where the software is executed by the controller). The software may be stored in any memory device and may include one or more separate programs, each of which includes an ordered list of executable instructions for implementing the functions described herein. When structured as a source program, the program is translated via a compiler, assembler, interpreter, etc., which may or may not be included in the memory 117.

[0025] It should be understood that any method described herein can be implemented at least in part as computer instructions stored on a computer medium (e.g., a computer memory as described above), and these instructions can be executed on a controller (such as a microprocessor). However, as mentioned, these methods can be implemented as any combination of electronic hardware and / or software.

[0026] The present disclosure generally relates to a fault isolation sensor system for determining whether a potential fault is more likely to occur on the rotor side or on the stator side. More specifically, the fault isolation sensor system includes a rotor antenna and a stator antenna, wherein the rotor antenna is disposed on an outer surface of a shaft and is configured to rotate around a central axis of the shaft, and the stator antenna is mounted separately from the shaft so that the rotor antenna rotates with the shaft relative to the stator antenna. A radio frequency (RF) sensor is disposed on the outer surface of the shaft and conductively connected to the rotor antenna. The RF sensor is configured to generate a measurement signal when the shaft rotates. The measurement signal is wirelessly transmitted from the rotor antenna to the stator antenna, and then wirelessly transmitted from the stator antenna to a controller. The controller is configured to monitor the measurement signal.

[0027] If the controller identifies a potential fault condition based on the measurement signal, the stator antenna can be interrogated to facilitate isolating the potential fault condition. If the interrogation results in a signal indicating a potential fault condition on the stator side, the stator antenna and other stator-side components can be checked to identify and / or resolve the fault. If the interrogation does not produce a signal indicating a potential fault condition on the stator side, the rotor antenna and other rotor-side components can be checked to identify and / or resolve the fault. A voltage standing wave ratio circuit (VSWRC) can be electrically connected to the stator antenna. The voltage standing wave ratio circuit (VSWRC) has 2 outputs representing the incident wave and the reflected wave, and with the addition of an analog divider circuit, can be constructed to output a voltage ratio or reflection coefficient of the reflected power divided by the incident power when interrogating the stator antenna. If the voltage ratio is <0.2 (or within other predetermined ranges or thresholds), the possible fault is not on the stator side, but on the rotor side. Optionally, a time domain reflectometer (TDR) can be used to provide not only the amount of reflected energy, but also the time it takes for the signal to propagate downward and backward to determine the location of the fault. When used with a voltage standing wave ratio circuit (VSWRC), a time domain reflectometer (TDR) can be used to determine whether a fault or potential fault is on the rotor side or on the stator side, and if the fault or potential fault is on the stator side, where the fault is located along the stator interconnect path or stator antenna. A time domain reflectometer (TDR) can be used alone without a voltage standing wave ratio circuit (VSWRC) to determine the location of a fault on the stator side. If a fault is not identified using a time domain reflectometer (TDR), it indicates that the fault is on the rotor side.

[0028] Figure 1 1 is a schematic diagram of a sensor system 100 in combination with a shaft 102 of a rotor assembly according to an embodiment. The sensor system 100 includes an RF sensor 104 disposed on the shaft 102 and a rotor antenna 106 also disposed on the shaft 102. For example, the RF sensor 104 and the rotor antenna 106 are both rigidly fixed (e.g., fixed in place) on an outer surface 108 of the shaft 102. The RF sensor 104 is conductively connected to the rotor antenna 106 via one or more wires, traces along a substrate, etc. The shaft 102 is cylindrical and oriented along a central axis 111. The shaft 102 is configured to rotate clockwise and / or counterclockwise around the central axis 111. The RF sensor 104 and the rotor antenna 106 rotate around the central axis 111 with the shaft 102.

[0029] The sensor system 100 also includes a stator antenna 110 that is separate and spaced from the shaft 102. The stator antenna 110 does not rotate with the shaft 102. The stator antenna 110 is disposed radially outward of the rotor antenna 106. The stator antenna 110 is aligned with the rotor antenna 106 so that the rotor antenna 106 and the stator antenna 110 are located at substantially the same position along the length of the axis 111. For example, the stator antenna 110 may radially overlap at least a portion of the rotor antenna 106 so that a line extending radially from the axis 111 through the rotor antenna 106 may also intersect the stator antenna 110. The stator antenna 110 may be mounted on a stator 118 ( Figure 2 1) or mounted to the stator 118. The stator member may alternatively represent a conductive housing that provides electromagnetic shielding, or may be disposed within a conductive housing that provides electromagnetic shielding. The stator antenna 110 may be rigidly fixed to the stator 118. The rotor antenna 106 is radially spaced apart from the stator antenna 110 by an air gap 122. The rotor antenna 106 is wirelessly (such as inductively) connected to the stator antenna 110 across the air gap 122.

[0030] In a non-limiting example, the rotor antenna 106 is an annular ring extending around the entire circumference of the shaft 102, and the stator antenna 110 is an arc around a portion of the circumference of the shaft 102 that is less than the entire circumference, such as Figure 1 and Figure 2 as shown in .

[0031] The stator antenna 110 is communicatively connected to a controller 112 of the sensor system 100. The controller 112 is spaced apart from the shaft 102. The controller 112 may be connected to the stator antenna 110 via a wired path 116. In operation, the RF sensor 104 is configured to generate a measurement signal when the shaft 102 turns or rotates. The measurement signal is communicated from the RF sensor 104 to the rotor antenna 106, and from the rotor antenna 106 to the stator antenna 110 across the air gap 122. As the shaft 102 rotates, the controller 112 monitors one or more electrical characteristics of the measurement signal over time. The controller 112 is configured to determine one or more characteristics of the shaft 102 based on the electrical characteristics of the measurement signal.

[0032] In an embodiment, the RF sensor 104 may be a passive sensor module that does not have an onboard power supply or a connected power supply (such as a battery or an energy harvesting device). The RF sensor 104 may be configured to generate a measurement signal in response to receiving a stimulus signal, so that the energy of the stimulus signal is used to power the generation and communication of the measurement signal. For example, the controller 112 may represent an interrogator and a reader. As an interrogator, the controller 112 generates a stimulus signal and controls the transmission of the stimulus signal from the stator antenna 110 to the RF sensor 104 via the rotor antenna 106. The RF sensor 104 may generate a measurement signal when receiving the stimulus signal by utilizing the energy of the stimulus signal. As a reader, the controller 112 receives and analyzes the measurement signal generated by the RF sensor 104 in response to receiving the stimulus signal. Having a voltage standing wave ratio circuit (VSWRC) 114 between the controller 112 and the stator antenna 110 advantageously allows interrogation of the stator antenna 110. More specifically, if the controller 112 determines that the measurement signal indicates a potential fault, the controller 112 may send an interrogation signal to the stator antenna 110 via the voltage standing wave ratio circuit VSWRC 114. The voltage standing wave ratio circuit VSWRC 114 may compare the ratio of the interrogation signal to the reflected signal. If the ratio is outside one or more predetermined ranges, or exceeds a predetermined threshold, the controller 112 may indicate that a potential fault condition exists on the stator side. If the ratio is within predetermined limits, the controller 112 may indicate that a potential fault condition exists on the rotor side. One or more predetermined ranges or predetermined thresholds may be stored in a memory of the controller 112. Advantageously, having an indication of the source or possible source of the fault may speed up inspection and repair. As described above, in addition to or in place of the voltage standing wave ratio circuit (VSWRC) 114, an optional time domain reflectometer (TDR) 115 may be present. The time domain reflectometer (TDR) 115 may be incorporated into the controller 112, or may be separate and communicate with the controller 112.

[0033] In an embodiment, the components of the sensor system 100 disposed on the shaft 102 are passive, which avoids mounting batteries or other active power components on or near the shaft 102. Such active power components may interfere with narrow gaps in the rotor assembly. Without active power components, the shaft-mounted components of the sensor system 100 can be relatively thin and can fit within the narrow gap between the shaft and the stator. The sensor system 100 can be retrofitted to existing rotor assemblies that are not designed to accommodate sensors disposed on the shaft.

[0034] although Figure 11 , the sensor system 100 may include multiple RF sensors 104 mounted at different locations on the shaft 102. For example, another RF sensor 104 may be disposed on the outer surface 108 of the shaft 102 at a relative circumferential position relative to the visible RF sensor 104 (e.g., a circumferential region along the shaft facing away). The stator antenna 110 is positioned adjacent to the rotor antenna 106 and is separated from the rotor antenna 106 by an air gap. The stator antenna 110 is operably connected to a controller 112. A voltage standing wave ratio circuit (VSWRC) 114 is operably connected between the controller 112 and the stator antenna 110. The controller 112 may be configured to receive measurement signals generated by the RF sensor 104 when determining one or more characteristics of the shaft 102 (such as torque, bending, fatigue, stress, strain rate, etc.). The controller 112 is configured to interrogate the stator antenna 110 by sending a signal to the stator antenna 110 through the voltage standing wave ratio circuit (VSWRC) 114. The reflected signal is compared to the transmitted signal to determine a ratio. The ratio is received by the controller 112 and the controller 112 can indicate a possible fault on the stator side or the rotor side depending on the ratio.

[0035] The sensor system 100 may optionally include more than one rotor antenna 106 and more than one stator antenna 110 located at different axial positions along the length of the shaft 102. For example, the rotor antenna 106 and the stator antenna 110 shown may define a first wireless connection pair, and the sensor system 100 may include at least one other wireless connection pair spaced apart from the first wireless connection pair. For example, the second wireless connection pair may be configured to communicate the measurement signal generated by the second RF sensor to the controller 112. The controller 112 may be configured to compare the measurement signals generated by the plurality of different RF sensors 104 when determining one or more characteristics of the shaft 102 (e.g., torque, bending, fatigue, stress, strain rate, etc.).

[0036] Figure 2 1 is a schematic cross-sectional perspective view of a sensor system 100 in combination with a rotor assembly including a shaft 102 and a stator 118. A rotor antenna 106 is disposed on an outer surface 108 of the shaft 102. The stator 118 has a concave recess 120 having a shape complementary to that of the shaft 102. A stator antenna 110 is attached to the concave recess 120 of the stator 118. The stator antenna 110 is electrically connected to a voltage standing wave ratio circuit (VSWRC) 114 via a wired path 116 (such as an RF coaxial cable), and the voltage standing wave ratio circuit (VSWRC) 114 is connected to a controller 112 via the RF coaxial cable. Figure 2In the example of , controller 112 is a full authority digital engine control (FADEC) or a portion of a full authority digital engine control (FADEC). The indication of the location of the fault or the potential location of the fault can be achieved in a variety of ways (including using the FADEC). The indication can be audible (such as using a speaker), or visual. For example, a display can provide the information. The display can be operably connected to the controller, including remotely. In addition, the connection is not necessarily continuous.

[0037] Figure 3 1 is a block diagram of a sensor system 100 according to an embodiment. Optionally, the controller 112 can be remote from the stator 118 on which the stator antenna 110 is mounted. The controller 112 can be conductively connected to the stator antenna 110 via a wired path 116 (such as an RF coaxial cable), with a voltage standing wave ratio circuit (VSWRC) 114 in between. The rotor antenna 106 can be conductively connected to the RF sensor 104 via a conductive signal path 124 along the shaft 102, which can be provided by one or more wires. Optionally, the rotor antenna 106 is directly connected to a portion of the RF sensor 104 (such as a printed circuit board or substrate of the RF sensor 104) without a discrete wire passing through the space between the antenna 106 and the RF sensor 104.

[0038] Figure 4 1 is a diagram of a voltage standing wave ratio circuit (VSWRC) 114 for use with an embodiment of the fault isolation sensor system 100. The VSWRC 114 includes a passive 4-port RF network comprising two transmission lines 402, 404, two termination resistors 406, 408 and two RF power detectors 410, 412 including rectifier diodes and filter capacitors. When the controller 112 sends an interrogation signal, the VSWRC 114 measures the forward and reverse RF energy. By dividing the reflected energy by the incident energy (such as by using the controller 112 or an analog divider circuit), the VSWRC 114 can be used to monitor the RF interconnect integrity of the stator antenna 110 and other components electrically connected or otherwise connected to the stator antenna 110. Similarly, when the interrogation signal is sent by the controller 112 or the TDR 115, the TDR 115 can be used to measure the forward and reverse RF energy. The TDR 115 may also be used to determine the time of the returning RF signal, which may be advantageously used by the TDR 115 and / or the controller 112 to indicate the location or potential location of a fault on the stator side.

[0039] Figure 4The RF sensor 104 in the illustrated embodiment is a surface acoustic wave (SAW) sensor. The RF sensor 104 may be a fully quartz packaged surface acoustic wave (SAW) sensor. For example, the sensor 104 may be sealed between a quartz substrate and a second quartz layer. The surface acoustic wave (SAW) sensor 104 may include a first resonator, a second resonator, and a third resonator. The resonators may be disposed on a common substrate. The substrate may include quartz. The substrate may be fixed to the shaft 102 via an adhesive applied to an inner surface of the substrate facing the shaft 102. The surface acoustic wave (SAW) sensor 104 may optionally include a circuit board that includes or is connected to the substrate. The location of the RF sensor 104 on the shaft 102 provides a direct measurement of one or more characteristics (such as strain and temperature) via the resonator. For example, the first and second resonators may measure strain, and the third resonator may measure temperature. Strain measurements may be used to derive torque. Optionally, the strain resonator may be configured to resonate at different frequencies.

[0040] In an embodiment, the surface acoustic wave (SAW) sensor 104 is passive and is powered by receiving a stimulus signal. Each stimulus signal transmitted to the surface acoustic wave (SAW) sensor 104 via the rotor and stator antennas 106, 110 can have a wide spectrum. The spectrum of the stimulus signal can define the operating frequency range of the surface acoustic wave (SAW) sensor 104. The surface acoustic wave (SAW) sensor 104 converts the electrical stimulus signal into an acoustic signal that travels along the surface of the shaft 102. The measurement signal generated by the surface acoustic wave (SAW) sensor 104 may include a wide spectrum of the stimulus signal, with nulls or gaps in the spectrum representing the frequency of the resonator resonance. The controller 112 receives the measurement signal from the stator antenna 110, and can determine the resonant frequency of the resonator based on these nulls in the spectrum. The controller 112 is configured to determine one or more characteristics of the shaft 102, such as strain, torque, temperature, etc., based on the determined resonant frequency of the resonator.

[0041] Figure 5A schematic cross-sectional view of an exemplary embodiment of an aircraft engine 500 is depicted in FIG. The aircraft engine 500 is a combustion engine, such as a high bypass turboprop engine. The engines in other non-limiting examples may include or represent other turbine powered engines, such as turboshaft engines, turbofan engines, etc. The aircraft engine 500 includes various rotating shafts, such as a high pressure shaft 502, a low pressure shaft 504, a fan shaft 506, and an engine coupling shaft 508. The high pressure shaft 502 connects the high pressure turbine 510 to the high pressure compressor 512. The low pressure shaft 504 connects the low pressure turbine 514 to the low pressure compressor 516. The fan shaft 506 is connected to a fan section or propeller 518. The engine coupling shaft 508 connects the reduction gear 520 to the low pressure shaft 504. These shafts 502, 504, 506, 508 may represent different rotor assemblies or different components of a single rotor assembly.

[0042] The sensor system 100 may be incorporated into an aircraft engine 500. The sensor system 100 may be integrated with at least one of the shafts 502, 504, 506, 508 to monitor a characteristic of the shaft, such as, but not limited to, strain, torque, temperature, or rotational speed. The controller 112 may be configured to control the operation of the aircraft engine 500 based on one or more determined characteristics of the shaft 502. For example, the aircraft engine 500 may have a specified torque value or range. If the sensor system 100 determines that the torque value of the shaft 502 is outside of a predetermined torque range, the controller 112 may generate a control signal configured to change an operating setting of the aircraft engine 500, such as increasing the power output of the aircraft engine 500 or decreasing the power output based on the determined torque value. Although Figure 5 The aircraft engine 500 shown in FIG. 5 is a combustion engine, but the sensor system 100 described herein may be combined with other types of engines or machines including a rotor assembly (eg, a rotating shaft). Such machines may include electric motors, generators, other types of engines, and the like.

[0043] Although the fault isolation sensor system is generally described herein as being configured to monitor a SAW sensor on a stator of an engine, the fault isolation sensor system can be used to isolate faults in various electronic components of the engine, such as temperature sensors, pressure sensors, vibration sensors, speed sensors, position sensors, flow sensors, accelerometers, etc. The fault isolation sensor system can further monitor electronic components on various parts of the engine, such as the casing, rotor, shaft, inlet, exhaust, etc. In general, the fault isolation sensor system allows for fault isolation of relatively accessible components of the engine to help determine whether inspection and repair of less accessible components may be required.

[0044] The sensor system 100 described herein can enable determination of whether there is an interconnection fault at a specific location along the stator portion of the SAW system. Alternatively, use of TDR can enable determination of the physical location of the interconnection fault along the length of the interconnection of the stator portion of the SAW system (e.g., including the stator antenna 110).

[0045] In one embodiment, the stator portion of the SAW system includes a connector at the FADEC, a cable harness between the FADEC and booster compartments, an RF bias tee associated with a single-wire interface calibration EEPROM (electrically erasable programmable read-only memory), wiring inside the engine, an interface with the stator antenna 110 and associated termination resistors, and some or all of the stator antenna 110.

[0046] The SAW system may integrate health monitoring into the operation of the system, which may identify degradation in system performance. Such health monitoring may use the derived resonator quality factor and / or the measured noise associated with the calculation of a specific resonator frequency to help determine if system degradation is occurring. If the quality factor of the resonator is degrading, this may indicate degradation in the rotor SAW sensor or sensor mode on the shaft 102. If an increase in this standard deviation value is detected, voltage standing wave ratio measurements and / or time domain reflectometry measurements are made, and these results indicate normal operation and no degradation is observed, it may be inferred that the increased system RF losses are due to system components attached to the shaft 102 rather than the stator side. Conversely, if voltage standing wave ratio measurements and / or time domain reflectometry measurements are made, and these results show degradation, the problem is likely to exist on the stator side, and the shaft 102 and associated components are not the source of the potential failure.

[0047] If a fault is detected on the stator side using VSWR measurements, it may optionally be desirable to determine where along the length of the interconnect path the degradation is occurring. This can be done using a time domain reflectometer (TDR) 115. The TDR 115 can be used to identify where along the interconnect path a fault is occurring or may occur, and tell the operator what components on the stator side of the SAW system need to be inspected or replaced.

[0048] Examples of the types of failure modes that may be identified include the following, and any combination of one or more of the following: failures on the rotor side of the SAW system; failures associated with the wiring between the FADEC and the supercharger compartment; failures associated with the RF bias T and / or electrical overstress protection circuits associated with the EEPROM calibration device; failures associated with the wiring between the EEPROM calibration device and the stator antenna 110; failures associated with the interconnections to the stator antenna 110; failures associated with stator antenna trace cracks and / or antenna ablation; and failures associated with the terminating resistors of the stator antenna caused by fatigue or cracking of the SMT solder joints.

[0049] Figure 6 , a method for isolating a fault using a sensor system 100 is depicted, wherein the sensor system 100 includes a rotatable shaft 102 having a rotor antenna 106 disposed on an outer surface 108 thereof, and a stator antenna 110 mounted separately from the shaft 102 such that the rotor antenna 106 rotates with the shaft 102 relative to the stator antenna 110. The method may include generating an RF signal from a stator side, such as Figure 6 The RF signal may be generated during rotation of the shaft 102 and / or when the shaft 102 is not rotating. The method may also include receiving a measurement signal from the rotor antenna 106 using the stator antenna 110, such as Figure 6 As shown at step 604 in the method. The method may also include using a controller 112 communicatively connected to the stator antenna 110 to monitor the measurement signal, such as Figure 6 If the controller 112 determines that the measurement signal indicates a fault, it sends an interrogation signal via the voltage standing wave ratio circuit (VSWRC) 114 and compares the interrogation signal with the reflected signal, as shown in step 606. Figure 6 If the voltage ratio between the signals is above the threshold, a potential fault on the stator side is indicated; if the ratio is below the threshold, a potential fault on the rotor side is indicated, such as Figure 6 As shown in step 610.

[0050] The threshold may be predetermined or dynamic. For example, the threshold may be 1, 0.2, or another number. A range may be used instead of a threshold. The ratio may be considered as the reflected voltage divided by the incident voltage, which may give a reflection coefficient. In other words, the amplitude of the sent interrogation signal is known, and when the reflected amplitude is greater than a threshold (or range) (e.g., 0.2), then this may indicate a potential fault in the stator side.

[0051] The sensor system 100 and / or method described herein can be used for any suitable system in which it is desired to isolate and distinguish faults. The sensor system 100 and / or method can be advantageously used to isolate and distinguish faults on easily accessible or easily replaceable components of an engine or other system on the one hand, and to isolate and distinguish components that are not easily accessible or more difficult to replace on the other hand. For example, if the sensor system 100 indicates that a potential fault is associated with an easily accessible or easily replaceable component, rather than an inaccessible or inaccessible component, a reduction in repair time can be achieved because the repair can start from solving the easily accessible or inaccessible component. If the sensor system 100 indicates that a potential fault may be associated with an inaccessible or inaccessible component, repair efficiency can be achieved by first solving the component and potentially planning the time required for such repair and potentially arranging other maintenance or repairs to such components or adjacent structures. The sensor system 100 and / or method described herein can, for example, isolate a fault from other actual or potential faults and can distinguish between faults. When used with a TDR, or when the TDR is used alone, more specific information about the location or potential location of the fault can be determined, as described above. For example, the TDR may indicate a fault or potential fault at a specific location or distance along a stator interconnect path or stator antenna, or at another component such as electronic components on various portions of the engine such as the casing, rotor, shaft, inlet, exhaust, etc.

[0052] Further aspects of the disclosure are provided by the subject matter of the following clauses:

[0053] A fault isolation sensor system is provided, which may include: a rotor antenna, which is disposed on an outer surface of a shaft, and the shaft is configured to rotate around a central axis of the shaft; a radio frequency (RF) sensor, which is disposed on the outer surface of the shaft and conductively connected to the rotor antenna, and the RF sensor is configured to generate a measurement signal; a stator antenna, which is mounted separately from the shaft so that the rotor antenna rotates together with the shaft relative to the stator antenna, and the stator antenna is wirelessly connected to the rotor antenna across an air gap to receive the measurement signal from the rotor antenna; and a controller, which is communicatively connected to the stator antenna, and the controller is configured to monitor the measurement signal received from the stator antenna to determine one or more characteristics of the shaft. The system may further include at least one of: a voltage standing wave ratio circuit (VSWRC) electrically connected relative to the stator antenna and the controller, the VSWRC configured to determine a reflection coefficient of a stator-side interconnection path and the antenna; and a time domain reflectometer (TDR) for sending a TDR interrogation signal and receiving a TDR reflection signal, and determining a voltage ratio between the TDR interrogation signal and the TDR reflection signal over time.

[0054] The system according to the preceding clause may further have a controller configured to compare the voltage ratio with a predetermined threshold or range. The controller may also be configured to output a fault signal if the voltage ratio exceeds the predetermined threshold or is outside the range.

[0055] A system as described in any of the preceding clauses may have the VSWRC configured to divide reflected energy by incident energy to output the voltage ratio to the controller.

[0056] The system of any of the preceding clauses may include the time domain reflectometer (TDR).The time domain reflectometer (TDR) may be configured to determine a time for receiving a TDR reflected signal and, based on the time, output an indication of a location of a fault on the stator antenna.

[0057] A system as described in any of the preceding clauses may have the voltage standing wave ratio circuit (VSWRC).

[0058] A system according to any of the preceding clauses may have both the voltage standing wave ratio circuit (VSWRC) and the time domain reflectometer (TDR).

[0059] A system according to any of the preceding clauses may have the shaft and rotor as part of an aircraft engine.

[0060] A system according to any of the preceding clauses may have the controller comprising a full authority digital engine control (FADEC).

[0061] A fault isolation system is provided that includes means for isolating a fault or potential fault, such as means for indicating whether the fault or potential fault is on the rotor side or the stator side of a component, such as a rotating shaft of an engine.

[0062] A method is provided for determining whether a fault is on the rotor side or the stator side of a sensing system using a fault isolation sensor system according to any of the preceding clauses. The method may include comparing the voltage ratio with a predetermined range or threshold using the controller and indicating that the fault is in the stator antenna if the voltage ratio between the interrogation signal and the reflected signal is outside the predetermined range or exceeds a predetermined threshold, and indicating that the fault is in the rotor antenna if not.

[0063] A method is provided for determining whether a fault is on the rotor side or on the stator side using a fault isolation sensor system according to any of the preceding clauses, wherein the system comprises a time domain reflectometer (TDR). The method may include: using the controller to compare the voltage ratio with a predetermined range or threshold, and if the voltage ratio between the interrogation signal and the reflected signal is outside the predetermined range or exceeds a predetermined threshold, indicating that the fault is on the stator side, if not, indicating that the fault is on the rotor side; and if the fault is on the stator side, determining the time for the signal to propagate along the stator antenna and return to identify the location of the fault.

[0064] A method for isolating a fault in a sensor system is provided, the sensor system comprising: a rotatable shaft having a rotor antenna disposed on an outer surface thereof; a stator antenna, the stator antenna being mounted separately from the shaft so that the rotor antenna rotates with the shaft relative to the stator antenna. The method may include: generating a measurement signal; transmitting the measurement signal from the rotor antenna to the stator antenna; monitoring the measurement signal received from the stator antenna to determine one or more characteristics of the shaft; sending an interrogation signal to the stator antenna if the measurement signal is outside a predetermined range or exceeds a predetermined threshold; comparing the interrogation signal to a reflected signal; and indicating that the fault is on the stator side if the ratio between the interrogation signal and the reflected signal is outside a predetermined range or exceeds a predetermined threshold, and indicating that the fault is on the rotor side if not.

[0065] The system of the method according to the preceding clause may include a radio frequency (RF) sensor disposed on the shaft and configured to perform the step of generating a measurement signal when the shaft is rotating and when the shaft is not rotating.

[0066] The system of the method of the preceding clause may include a voltage standing wave ratio circuit (VSWRC) electrically connected relative to the stator antenna, the VSWRC configured to perform the step of comparing the interrogation signal to a reflected signal.

[0067] The system in the method according to the preceding clause may comprise a controller configured to indicate that the fault is on the stator side or that the fault is on the rotor side.

[0068] A method as in any preceding clause, wherein if the fault is indicated on the stator side, propagating a signal and measuring the time for signal reflection to identify the location of the fault along the stator antenna.

[0069] A method as in any of the preceding clauses, wherein the sensor system is on a shaft of an aircraft engine.

[0070] A controller may be provided, the controller being configured to isolate a fault in a sensor system. The sensor system may optionally include a rotatable shaft and a stator antenna, the shaft having a rotor antenna disposed on an outer surface thereof, the stator antenna being mounted separately from the shaft so that the rotor antenna rotates with the shaft relative to the stator antenna. The controller may be configured to: generate a measurement signal; transmit the measurement signal from the rotor antenna to the stator antenna; and monitor the measurement signal received from the stator antenna to determine one or more characteristics of the shaft. The controller may also be configured to: send an interrogation signal to the stator antenna if the measurement signal is outside a predetermined range or exceeds a predetermined threshold; compare the interrogation signal with a reflected signal; and indicate that the fault is on the stator side if the ratio between the interrogation signal and the reflected signal is outside a predetermined range or exceeds a predetermined threshold, and if not, indicate that the fault is on the rotor side. The controller may be selectively used with any of the foregoing clauses.

[0071] A means for indicating the location of a fault or potential fault may be provided as part of any of the preceding clauses. The means for indicating the location of the fault or potential fault may include a visible and / or audible alarm or other notification.

[0072] Those skilled in the art will appreciate that various modifications, changes and combinations may be made to the above-described embodiments without departing from the scope of the present disclosure, and such modifications, changes and combinations should be considered to be within the scope of the disclosed concepts.

Claims

1. A fault isolation sensor system, characterized in that: include: a rotor antenna disposed on an outer surface of a shaft configured to rotate about a central axis of the shaft; a radio frequency (RF) sensor disposed on the outer surface of the shaft and conductively connected to the rotor antenna, the RF sensor being configured to generate a measurement signal; a stator antenna mounted separately from the shaft so that the rotor antenna rotates together with the shaft relative to the stator antenna, the stator antenna being wirelessly connected to the rotor antenna across an air gap to receive the measurement signal from the rotor antenna; a controller communicatively connected to the stator antenna, the controller configured to monitor the measurement signals received from the stator antenna to determine one or more characteristics of the shaft; as well as At least one of the following: a voltage standing wave ratio circuit (VSWRC) electrically connected relative to the stator antenna and the controller, the VSWRC configured to determine a reflection coefficient of a stator-side interconnect path and the antenna; as well as A time domain reflectometer (TDR) is configured to send a TDR interrogation signal and receive a TDR reflected signal, and to determine a voltage ratio between the TDR interrogation signal and the TDR reflected signal over time.

2. The fault isolation sensor system according to claim 1, characterized in that: in, The controller is configured to compare the voltage ratio to at least one of a predetermined threshold or range.

3. The fault isolation sensor system according to claim 2, characterized in that: in, The controller is configured to output a fault signal if the voltage ratio is at least one of exceeding the predetermined threshold or being outside the range.

4. The fault isolation sensor system according to claim 1, characterized in that: in, The VSWRC divides the reflected energy by the incident energy to output the voltage ratio to the controller.

5. The fault isolation sensor system according to claim 1, characterized in that: in, When the fault isolation sensor system includes the TDR, the TDR is configured to determine a time for receiving a TDR reflection signal and, based on the time, output an indication of a fault location on the stator antenna.

6. The fault isolation sensor system according to claim 1, characterized in that: in, When the fault isolation sensor system includes the TDR, the TDR is configured to determine a time for receiving a TDR reflected signal and, based on the time, output an indication of a fault location on a stator interconnection path.

7. The fault isolation sensor system according to claim 1, characterized in that: The invention comprises the voltage standing wave ratio circuit (VSWRC) and the time domain reflectometer (TDR).

8. The fault isolation sensor system according to claim 1, characterized in that: in, The shaft is part of an aircraft engine.

9. The fault isolation sensor system according to claim 8, characterized in that: in, The shaft is one of a high pressure shaft, a low pressure shaft, a fan shaft, and an engine coupling shaft.

10. The fault isolation sensor system according to claim 1, characterized in that: in, The controller includes a full authority digital engine control (FADEC).

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