Methods and systems for non-contact magnetostrictive sensor runout compensation

A stress sensing system for measuring stress in a conductive target material includes at least one sensor positioned proximate to the conductive target material. The sensor is configured to measure stress in the conductive target material and to transmit a signal indicative of the measured stress to a controller. The controller is coupled in communication with the sensor. The controller is configured to receive the signal from the sensor, determine a runout portion of the signal corresponding to the runout of the conductive target material, determine a runout pattern waveform from the runout portion, and subtract the runout pattern waveform from the signal.

BACKGROUND

Conductive materials have magnetostrictive properties that cause the materials to change shape in the presence of an applied magnetic field. The inverse is also true. When a force is applied to a conductive material, the magnetic properties, such as magnetic permeability, of the material change. A magnetostrictive sensor may sense the changes in magnetic permeability and, because the changes are proportional to the amount of stresses applied to the conductive material, the resulting measurement may be used to calculate the amount of stress.

Stationary magnetostrictive sensors proximate to a moving conductive material, such as a rotating shaft, sense the magnetic permeability of an air gap defined between the magnetostrictive sensor and the conductive material (e.g., mechanical vibration) and variation in the conductive material properties (e.g., runout) as well as the permeability of the conductive target. The changes in the magnetic permeability as a result of stress being applied to the conductive material, however, may be small compared to the mechanical vibration and runout of the conductive material, making accurate measurement of stress in the conductive material difficult. In some instances, the runout and/or mechanical vibration result in signal noise that may have amplitudes greater than that of the stress signal, thereby completely obscuring the stress signal.

SUMMARY

The subject matter described herein relates generally to stress sensing in conductive materials, and more particularly, to methods and systems for reducing runout and/or mechanical noise in torque signals attributable to runout and mechanical vibration.

In one aspect, a stress sensing system for measuring stress in a conductive target material is provided. The stress sensing system includes at least one sensor positioned proximate to the conductive target material. The sensor is configured to measure stress in the conductive target material and to transmit at least one signal indicative of the measured stress. The system also includes at least one controller coupled in communication with the sensor. The controller is configured to receive the stress signal from the sensor, determine a runout portion of the stress signal corresponding to runout of the conductive target material, determine a runout pattern waveform from the runout portion, and subtract the runout pattern waveform from the stress signal.

In another aspect, a computer-implemented method for reducing runout and vibration noise from a stress sensing system is provided. The method includes receiving at least one signal from at least one stress sensor. The signal is indicative of stress in a conductive target material. In addition, the method includes determining a runout portion of the signal corresponding to runout of the conductive target material. Moreover, the method includes determining a runout pattern waveform from the runout portion, and subtracting the runout pattern waveform from the stress signal.

In yet another aspect, a non-transitory computer readable medium that includes computer executable instructions for reducing runout and vibration noise from a stress sensing system is provided. The stress sensing system includes a computing device, wherein when executed by the computing device, the computer executable instructions cause the computing device to receive at least one signal from at least one stress sensor. The signal is indicative of stress in a conductive target material. The computer executable instructions cause the computing device to determine a runout portion of the signal that corresponds to runout of the conductive target material, and determine a runout pattern waveform from the runout portion of the signal. Furthermore, the computer executable instructions cause the computing device to subtract the runout pattern waveform from the signal.

DETAILED DESCRIPTION

Unless otherwise indicated, approximating language, such as “generally,” “substantially,” and “about,” as used herein indicates that the term so modified may apply to only an approximate degree, as would be recognized by one of ordinary skill in the art, rather than to an absolute or perfect degree. Approximating language may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations are identified. Such ranges may be combined and/or interchanged, and include all the sub-ranges contained therein unless context or language indicates otherwise.

Additionally, unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, for example, a “second” item does not require or preclude the existence of, for example, a “first” or lower-numbered item or a “third” or higher-numbered item.

As used herein, the phrase “magnetic permeability” includes the relative increase or decrease in the magnetic flux inside a material compared with the magnetic field in which the material is located.

The term “runout,” as used herein, includes a condition in which varying material conditions (e.g., surface imperfections, localized stresses, etc.) cause a change to a stress signal that is not related to actual stress in the material.

As used herein, the terms “processor”, “computer”, and “controller”, and related phrases, e.g., “processing device” and “computing device” are not limited to just those integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), and other programmable circuits, and these terms are used interchangeably herein. In the embodiments described herein, memory may include, but is not limited to, a computer-readable medium, such as a random access memory (RAM), and a computer-readable non-volatile medium, such as flash memory. Alternatively, a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), and/or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, additional input channels may be, but are not limited to, computer peripherals associated with an operator interface such as a mouse and a keyboard. Alternatively, other computer peripherals may also be used that may include, for example, but not be limited to, a scanner. Furthermore, in the exemplary embodiment, additional output channels may include, but not be limited to, an operator interface monitor.

The present disclosure provides techniques that may be used with torque sensors to decrease and/or remove runout and mechanical vibration signals that are not related to torque of a rotating shaft. In particular, embodiments in the disclosure may be used to determine a runout signal pattern and removing it from the torque signal received from the torque sensor. In addition, the disclosure provides embodiments that can be used to combine the runout compensated torque signals from two or more torque sensors to correct for mechanical vibration of the shaft. Torque sensors typically sense the magnetic permeability of an air gap defined between the torque sensor and the rotating shaft and material property variations. In one embodiment, the techniques described include monitoring a rotational speed of the shaft and receiving a torque sensor signal corresponding to a zero stress condition of the shaft (i.e., when the shaft is rotating with no load). In other embodiments, the techniques described may include monitoring a rotational speed of the shaft already subject to stress and receiving a torque sensor signal corresponding to the shaft stress. The signal received from the torque sensor may facilitate the identification of a shaft runout pattern. The identified shaft runout pattern can then be removed from the subsequent torque signal received from the torque sensor. Removing runout and vibration signals from the torque signal can help improve accuracy in determining torque of the shaft. Other embodiments are within the scope of the disclosure.

FIG. 1is a schematic view of an exemplary stress sensing system10for sensing stresses induced in a conductive target material12. In the exemplary embodiment, stress sensing system10includes a conductive target material12, a first sensor head, generally indicated at14, and a second sensor head, generally indicated at16. Alternatively, stress sensing system10can include more than two sensor heads. In the exemplary embodiment, conductive target material12can be, for example, and without limitation, a rotatable shaft or rotor. First sensor head14and second sensor head16can include, for example, and without limitation, stress sensors, and in particular, magnetostrictive torque sensors. In such an embodiment, stress sensing system10can be a torque sensing system. Alternatively, stress sensing system10can be any type of stress sensing system that is capable of sensing stress in any type of conductive target material. In the exemplary embodiment, first sensor head14can be positioned proximate to rotatable shaft12such that an air gap18is defined between sensor head14and rotatable shaft12. In addition, second sensor head16can be positioned proximate to rotatable shaft12such that an air gap20is defined between sensor head16and rotatable shaft12. Stress sensing system10also includes at least one speed sensor22for sensing rotation of rotatable shaft12. Speed sensor22can include, for example, and without limitation, a Keyphasor®, tachometer, or other once-per-turn or multiple-events-per revolution reference. A Keyphasor may include, for example, a proximity switch used to identify the beginning and completion of each revolution of rotatable shaft12. First and second sensor heads14and16and speed sensor22can be coupled to a controller24that includes a power supply component26for supplying the electrical current necessary to generate a magnetic flux used for sensing stress in rotatable shaft12.

In some alternative embodiments, additional sensors (not shown), for example, and without limitation, proximity, magnetic field, and/or temperature, may be positioned proximate to rotatable shaft12. Proximity sensors may be used to monitor air gaps18and20defined between rotatable shaft12and sensor heads14and16, respectively. Magnetometers may be used to monitor background magnetic fields, for example, and without limitation, the earth's magnetic field and extraneous electromagnetic interference (EMI). In addition, temperature sensors may be used to monitor temperature changes, including ambient environment, first and second sensor heads14and16, and/or rotatable shaft12. Gap changes in air gaps18and20, background EMI, and/or temperature changes may affect the data signal received by one or more detection coils (not shown) of first and second sensor heads14and16. By monitoring air gaps18and20, temperature changes, and background EMI, a magnitude of the assorted effects may be substantially reduced by controller24.

In the exemplary embodiment, power supply component26can include, for example, and without limitation, at least one of a battery, a wireless power supply device, and/or a wired power supply device. In one alternative embodiment, a battery can transmit power to sensor heads14and16, and speed sensor22through controller24. In another alternative embodiment, a wireless power supply device can include any power source that enables operation of stress sensing system10as described herein, such as, but without limitation, an inductive power supply. The wireless power supply device can be located separately from sensor heads14and16, and speed sensor22. Alternatively, the wireless power supply device may be positioned in any location that enables stress sensing system10to function as described herein. Moreover, in another alternative embodiment, the wired power supply device can be configured to transmit power directly to sensor heads14and16, and speed sensor22via one or more power cables (not shown). Furthermore, in other alternative embodiments, the wireless and wired power supply devices may include a battery that may be used to transmit power to stress sensing system10during a power failure. In such alternative embodiments, during normal operation of stress sensing system10, the battery may be in a stand-by mode.

As shown inFIG. 1, in the exemplary embodiment, rotatable shaft12includes an axis system including a vertical axis “A” and a horizontal axis “B.” First sensor head14and second sensor head16are positioned apart from each other at a predetermined radial angle α. In the exemplary embodiment, radial angle α is 180°, defined by first sensor head14and second sensor head16being disposed on axis “B” on opposite sides of rotatable shaft12. Alternatively, radial angle α can be any predetermined angle greater than 0° and less than 360°. Furthermore, as described above, stress sensing system10can include more than two sensor heads. In such an embodiment, each sensor head can be spaced from an adjacent sensor head by a predetermined radial angle greater than 0° and less than 360°. For example, and without limitation, in one alternative embodiment, stress sensing system10can include four sensor heads spaced equidistant about rotatable shaft12at 90° angles. In the exemplary embodiment, speed sensor22is positioned on axis “A,” substantially equidistant from first sensor head14and second sensor head16. Alternatively, speed sensor22can be positioned at any location about rotatable shaft12that enables stress sensing system10to function as described herein.

FIG. 2is a schematic plot of an exemplary torque signal28received by controller24from a sensor head, such as sensor head14or16(shown inFIG. 1), over a period of time, i.e., in the time domain. While the data signals and plots described herein are described in relation to the time domain, it is noted that the operations described can be equally applied in the frequency domain. In the exemplary embodiment, as described above, stress sensing system10monitors a rotation speed of the rotatable shaft12(shown inFIG. 1) while receiving torque signal28. Speed sensor22provides a rotation signal (not shown) to controller24(shown inFIG. 1), such as a voltage spike that exceeds a predetermined threshold value, during each rotation of rotatable shaft12. In one embodiment, the shaft speed can be assumed to be constant between each threshold spike of the rotation signal, and as such, an angular position of rotatable shaft12can be estimated as a function of the period between each threshold spike using a linear interpolation technique. As described herein, a portion of torque signal28, generally indicated at30, corresponding to a zero stress condition of rotatable shaft12(i.e., when the shaft is rotating with no load) can be used to isolate a synchronous runout signal30(shown inFIG. 3). As shown in the enlarged portion of the plot, torque signal portion30is shown in evenly spaced time intervals as a rotation speed of rotatable shaft12is increased. As such, spacing between peaks of torque signal portion30narrows as the rotation speed increases. The regularity of the runout of rotatable shaft12can be difficult to determine from torque signal portion30in such a time domain.

As shown inFIG. 2, torque signal28has an output value that cycles generally between about −0.2 output units and about −0.06 output units during a period between about 0 time units and about 175 time units. In one embodiment, the output units may include, for example, and without limitation, volts, and the time units may include for example, and without limitation, seconds. Alternatively, the output units may include any type of output unit output by sensor heads14and16. In addition, the time units may include any time unit that enables stress sensing system10to function as described herein. In the exemplary embodiment, at about 175 time units, the output value range of torque signal28increases. In the exemplary embodiment, the period between about 0 time units and about 175 time units corresponds to a zero stress condition of rotatable shaft12. In some embodiments, additional data received from other sensors and/or secondary measures, for example, and without limitation, output of a generator coupled to rotatable shaft12, can be used to confirm and/or verify a zero stress condition of rotatable shaft12. In the exemplary embodiment, the output values of torque signal28between about 0 time units and about 175 time units is indicative of runout and/or mechanical vibration of rotatable shaft12, for example, and without limitation, due to rotatable shaft12imperfections. In the exemplary embodiment, torque signal28can be collected or received by controller24on a time basis. However, torque signal28needs to be converted to a synchronous torque signal with respect to an angular position of rotatable shaft12.

FIG. 3is a schematic plot of exemplary synchronous runout torque signal portion32after resampling of torque signal portion30(shown inFIG. 2) to an angle domain corresponding to rotatable shaft12(shown inFIG. 1) by controller24(shown inFIG. 1). In the exemplary embodiment, torque signal portion28corresponding to a zero stress condition of rotatable shaft12can be used by controller24to determine synchronous runout torque signal portion32. For example, and without limitation, torque signal portion30corresponds to a period between about 70 time units and about 140 time units, as shown inFIG. 2. In an alternative embodiment, any portion of torque signal28, including portions that do not correspond to a zero stress condition of rotatable shaft12, may be used by controller24. In the exemplary embodiment, runout of rotatable shaft12is typically fixed with respect to an angular positioned of rotatable shaft12. Torque signal portion30, however, can be collected or received by controller24on a time basis, which is referred to herein as asynchronous with respect to an angular position of rotatable shaft12. As such, torque signal portion30can be converted by controller24to synchronous torque runout signal32with respect to an angular position of rotatable shaft12. This facilitates averaging synchronous torque runout signal32with corresponding data signals (not shown) received by additional sensor heads, such as sensor heads14and16(shown inFIG. 1). In the exemplary embodiment, synchronous torque runout signal32corresponds to five revolutions of rotatable shaft12. Alternatively, fewer or greater than five revolutions of rotatable shaft12may be used to determine synchronous torque runout signal32. As shown inFIG. 3, spacing between peaks of synchronous torque runout signal32are generally evenly spaced. As such, the regularity of the runout pattern of rotatable shaft12can be determined from synchronous torque runout signal32in such an angle domain.

FIG. 4is a schematic plot of exemplary time-synchronous averaged runout pattern40after averaging of synchronous torque runout signal32(shown inFIG. 3) by controller24(shown inFIG. 1). In the exemplary embodiment, noise and/or variance in synchronous torque runout signal32can be reduced or eliminated by averaging multiple revolutions of rotatable shaft12(shown inFIG. 1) using synchronous torque runout signal32. As described above, in the exemplary embodiment, synchronous torque runout signal32corresponds to five revolutions of rotatable shaft12. The signal data corresponding to each revolution can be combined with the signal data corresponding to each of the other revolutions and averaged to approximate the runout pattern of rotatable shaft12. The approximated runout pattern of rotatable shaft12is illustrated by time-synchronous averaged runout pattern40. In alternative embodiments, any number of revolutions of rotatable shaft12can be used in combination with synchronous torque runout signal32to determine time-synchronous averaged runout pattern40.

FIG. 5is a schematic plot of a runout pattern waveform50and a compensated torque signal waveform52. In the exemplary embodiment, time-synchronous averaged runout pattern40can be converted back into the time domain by controller24(shown inFIG. 1) to generate runout pattern waveform50and can be subtracted from torque signal28to generate compensated torque signal waveform52. As shown inFIG. 5, revolution to revolution variance due to rotatable shaft12(shown inFIG. 1) runout is substantially eliminated when compensated torque signal waveform52is compared to torque signal28(shown inFIG. 2). In the exemplary embodiment, compensated torque signal waveform52is generated in real-time by controller24. For example, in one embodiment, during startup or initial rotation of rotatable shaft12, torque signal28under a zero stress condition can be received or collected by controller24. In an alternative embodiment, controller24receives torque signal28from sensor heads14and16(shown inFIG. 1) continuously. In the exemplary embodiment, runout pattern waveform50can be determined and subsequently removed from torque signal28in real-time. Alternatively, in one embodiment, rotatable shaft12can be rotated under a zero stress condition and controller24may determine runout pattern waveform50and store it in memory for future use with torque signal28, for example, at a future time when rotatable shaft12is rotating under a non-zero stress condition.

FIG. 6is schematic of a first plot60of a first compensated torque signal waveform62, a second plot64of a second compensated torque signal waveform66, and a third plot68of an averaged compensated torque signal waveform70. In the exemplary embodiment, noise in first compensated torque signal waveform62and second compensated torque signal waveform66due to mechanical vibration of rotatable shaft12can be reduced or eliminated by averaging the torque signals of multiple sensor heads, such as sensor heads14and16(shown inFIG. 1). For example, as shown inFIG. 6, first compensated torque signal waveform62and second compensated torque signal waveform66each contain noise due in part to mechanical vibration of rotatable shaft12. As such, while first compensated torque signal waveform62and second compensated torque signal waveform66are both measuring the stress in rotatable shaft12, they are not providing the signals. In the exemplary embodiment, controller24(shown inFIG. 1) can combine first compensated torque signal waveform62and second compensated torque signal waveform66and determine averaged compensated torque signal waveform70by applying a conventional averaging technique. As such, averaged compensated torque signal waveform70provides a waveform indicative of the stress in rotatable shaft12with runout and mechanical vibration noise substantially decreased or eliminated from the waveform. This facilitates providing a torque measurement corresponding to rotatable shaft12having an increased accuracy. Furthermore, in instances where the runout and mechanical vibration noise may have greater amplitude than the torque data, averaged compensated torque signal waveform70facilitates discriminating the torque data from such runout and mechanical vibration noise.

FIGS. 7A and 7Bis a is a block diagram of an exemplary method700that facilitates reducing or eliminating signal noise due to runout and mechanical vibrations from torque signal28(shown inFIG. 2). In the exemplary embodiment, method700includes receiving702a torque signal28from one or more sensor heads14and16(shown inFIG. 1) of stress sensing system10. A portion of the signal corresponding to runout of rotatable shaft12is determined704. For example, determining the runout portion of signal28includes estimating706a speed of rotatable shaft12by finding threshold crossings or spikes in a rotation signal (not shown) received by controller24(shown inFIG. 1). An angular position of rotatable shaft12can be estimated by applying linear interpolation to a period between adjacent threshold crossings or spikes in a rotation signal. In one embodiment, a zero stress portion of torque signal28(torque signal portion30shown inFIG. 2) is selected708. In another embodiment, any portion of torque signal28may be selected by controller24. In the exemplary embodiment, torque signal portion30is resampled710to an angle domain corresponding to rotatable shaft12. Time-synchronous averaged runout pattern40is extracted712from torque signal portion30. In some embodiments, the time-synchronous averaged runout pattern40is generated by averaging multiple portions of torque signal portion30corresponding to a single rotation of rotatable shaft12together. Time-synchronous averaged runout pattern40is converted714to the time domain to generate runout pattern waveform50. In some embodiments, time-synchronous averaged runout pattern40is converted to the frequency domain. In the exemplary embodiment, runout pattern waveform50is subtracted716from torque signal28to generate compensated torque signal waveform52, which is substantially free of noise related to the runout of rotatable shaft12. In embodiments with more than one sensor head, such as sensor heads14and16(shown inFIG. 1), signals from the multiple sensor heads are averaged718together to facilitate reducing noise related, at least in part, to mechanical vibrations of rotatable shaft12.

FIG. 8is a block diagram of controller24that can be used to operate stress sensing system10(shown inFIG. 1). In the exemplary embodiment, controller24can be one of any type of controller typically provided by a manufacturer of stress sensing system10to control operation of stress sensing system10. Controller24may execute operations to control the operation of stress sensing system10based at least partially on instructions from human operators. Operations executed by controller24typically include controlling power output of sensor heads14and16(shown inFIG. 1), and speed sensor22(shown inFIG. 1), and receiving torque signals from the sensor heads, such a torque signal28(shown inFIG. 2). Controller24may also perform the various operations described herein to facilitate determining averaged compensated torque signal waveform70(shown inFIG. 6).

In the exemplary embodiment, controller24typically includes a memory device72and a processor74coupled to memory device72. Processor74may include one or more processing units, such as, without limitation, a multi-core configuration. Processor74can be any type of processor that permits controller24to function as described herein. In some embodiments, executable instructions can be stored in memory device72. Controller24can be configurable to perform one or more operations described herein by programming processor74. For example, processor74may be programmed by encoding an operation as one or more executable instructions and providing the executable instructions in memory device72. In the exemplary embodiment, memory device72can be one or more devices that enable storage and retrieval of information such as executable instructions or other data. Memory device72may include one or more computer readable media, such as, without limitation, random access memory (RAM), dynamic RAM, static RAM, a solid-state disk, a hard disk, read-only memory (ROM), erasable programmable ROM, electrically erasable programmable ROM, or non-volatile RAM memory. The above memory types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.

Memory device72may be configured to store any type of data, including, without limitation, torque signal28and runout pattern waveform50. In some embodiments, processor74can remove or “purge” data from memory device72based on the age of the data. For example, processor74may overwrite previously recorded and stored data, such as runout pattern waveform50, associated with a subsequent time or event. In addition, or alternatively, processor74may remove data that exceeds a predetermined time interval. In addition, memory device72can include, without limitation, sufficient data, algorithms, and commands to facilitate monitoring of sensor heads14and16, and in particular, torque signals28being generated by stress sensing system10.

In some embodiments, controller24includes a presentation interface76coupled to processor74. Presentation interface76can present information, such as, and without limitation, runout pattern waveform50, compensated torque signal waveform52, averaged compensated torque signal waveform70, and operating conditions of stress sensing system10, to a user78. In one embodiment, presentation interface76can include a display adapter (not shown) coupled to a presentation device (not shown). The presentation device can include such devices as a cathode ray tube (CRT), a liquid crystal display (LCD), an organic LED (OLED) display, or an “electronic ink” display. In some embodiments, presentation interface76can include one or more presentation devices. In addition, or alternatively, presentation interface76can include an audio output device (not shown), for example, without limitation, an audio adapter or a speaker (not shown).

In some embodiments, controller24can include a user input interface80. In the exemplary embodiment, user input interface80can be coupled to processor74and can receive input from user78. User input interface80may include, for example, without limitation, a keyboard, a pointing device, a mouse, a stylus, a touch sensitive panel, such as, without limitation, a touch pad or a touch screen, and/or an audio input interface, such as, without limitation, a microphone. A single component, such as a touch screen, may function as both a presentation device of presentation interface76and user input interface80.

In the exemplary embodiment, a communication interface82can be coupled to processor74and can be configured to be coupled in communication with one or more other devices, such as sensor heads14and16, and to perform input and output operations with respect to such devices while performing as an input channel. For example, communication interface82may include, without limitation, a wired network adapter, a wireless network adapter, a mobile telecommunications adapter, a serial communication adapter, or a parallel communication adapter. Communication interface82may receive a data signal from or transmit a data signal to one or more remote devices. For example, in some embodiments, communication interface82of controller24may transmit/receive a data signal to/from sensor heads14and16, or speed sensor22.

Presentation interface76and communication interface82can be capable of providing information suitable for use with the methods described herein, such as, providing information to user78or processor74. Accordingly, presentation interface76and communication interface82may be referred to as output devices. Similarly, user input interface80and communication interface82can be capable of receiving information suitable for use with the methods described herein and may be referred to as input devices.

In contrast to known stress sensing systems, the stress sensing systems and methods described herein may be used to identify and reduce or eliminate signal noise attributed to runout and/or mechanical vibration of a conductive target material from a torque signal received from a torque sensor. Specifically, the stress sensing systems and methods described herein can help measure an output, such as a voltage, from each of the sensor heads when the conductive target material is under a zero stress condition, and determine a runout pattern of the conductive target material from the measured output signal. The runout pattern can be averaged across several revolutions of the conductive target material to facilitate reducing noise in the signal, and can then be subtracted from the original signal to substantially remove the runout noise from the torque signal. The torque signals from several torque sensors can be averaged to facilitate reducing or removing noise attributed to mechanical vibration of the conductive target material. Therefore, in contrast to known stress sensing systems, the stress sensing systems and methods described may be used to provide a torque measurement corresponding to the conductive target material having an increased accuracy. Furthermore, in instances where the runout and mechanical vibration noise may have greater amplitude than the torque signal, the stress sensing systems and methods described herein may be used to discriminate the torque data from such runout and mechanical vibration noise.

An exemplary technical effect of the systems and methods described herein includes at least one of (a) determining runout and mechanical vibration noise in a torque signal; (b) identifying the runout pattern in the torque signal; (c) removing to reducing the effects of the runout pattern on the torque signals; and (d) removing or reducing the effects of mechanical vibration of a conductive target material from the torque signal.

While the disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosure is not limited to such disclosed embodiments. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the disclosure. Additionally, while various embodiments of the disclosure have been described, it is to be understood that aspects of the disclosure may include only some of the described embodiments. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

The methods and systems described herein are not limited to the specific embodiments described herein. For example, components of each system and/or steps of each method may be used and/or practiced independently and separately from other components and/or steps described herein. In addition, each component and/or step may also be used and/or practiced with other assemblies and methods.