阅读说明：本技术 谐振传感器的传感器频率自动定心 (Sensor frequency self-centering of resonant sensors ) 是由 思德哈斯·马路 瓦蒂姆·康拉德 马修·比尔兹沃斯 塔甲斯维·德斯 于 2020-03-26 设计创作，主要内容包括：系统可以包括：电阻-电感-电容传感器、被配置为以驱动频率驱动电阻-电感-电容传感器的驱动器,以及测量电路,其通信地耦合至电阻-电感-电容传感器并被配置为确定电阻-电感-电容传感器的谐振频率的测量变化,并且基于该测量变化来修改驱动频率。(The system may include: the apparatus includes a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a drive frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to determine a measured change in a resonant frequency of the resistive-inductive-capacitive sensor and modify the drive frequency based on the measured change.)

1. A system, comprising:

a resistive-inductive-capacitive sensor;

a driver configured to drive the resistive-inductive-capacitive sensor at a drive frequency; and

a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor, the measurement circuit configured to:

determining a measured change in a resonant frequency of the resistive-inductive-capacitive sensor; and

modifying a drive frequency based on the measured change.

2. The system of claim 1, wherein the measurement circuit is further configured to:

measuring at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor; and

determining the measured change in the resonant frequency of the resistive-inductive-capacitive sensor based on at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor.

3. The system of claim 2, wherein the measurement circuit is further configured to:

measuring at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor; and

modifying the drive frequency when a change in at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor exceeds a threshold.

4. The system of claim 3, wherein the threshold is based on a quality factor of the resistive-inductive-capacitive sensor.

5. The system of claim 1, wherein the measurement circuit is further configured to modify the drive frequency when the measurement variation exceeds a threshold.

6. The system of claim 5, wherein the threshold is based on a quality factor of the resistive-inductive-capacitive sensor.

7. The system of claim 1, wherein the measurement circuit further comprises a quality factor estimator configured to estimate a quality factor of the resistive-inductive-capacitive sensor.

8. The system of claim 7, wherein the quality factor estimator is configured to estimate the quality factor based on at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor.

9. The system of claim 7, wherein the measurement circuit is further configured to modify the drive frequency based on the quality factor.

10. The system of claim 1, wherein the measurement circuit is configured to modify the drive frequency by:

determining a change in phase information associated with the resistive-inductive-capacitive sensor; and

adjusting the drive frequency by a frequency change based on the phase information of the resistive-inductive-capacitive sensor and a slope of a phase versus frequency curve.

11. The system of claim 10, wherein the measurement circuit is configured to calculate that the change in frequency is equal to the change in phase information divided by the slope.

12. The system of claim 11, wherein:

the measurement circuit further comprises a quality factor estimator configured to estimate a quality factor of the resistive-inductive-capacitive sensor; and

the measurement circuit is configured to calculate the slope based on the quality factor.

13. The system of claim 1, wherein the measurement circuit is configured to modify the drive frequency to match a resonant frequency of the resistive-inductive-capacitive sensor.

14. The system of claim 1, wherein the measurement circuit is configured to verify that the modification to the drive frequency causes the drive frequency to match a resonant frequency of the resistive-inductive-capacitive sensor.

15. The system of claim 1, wherein the measurement circuit is configured to modify the drive frequency such that the system operates in a linear region of a phase versus frequency curve of the resistance-inductance-capacitance sensor.

16. The system of claim 1, wherein the measurement circuitry is configured to:

blanking measurement is performed on the phase information of the resistance-inductance-capacitance sensor in a measurement period after the drive frequency is modified; and

ensuring that the phase information changes caused by the modification of the drive frequency are not communicated to downstream processing.

17. The system of claim 1, wherein the measurement circuitry is configured to:

measuring phase information associated with the resistive-inductive-capacitive sensor; and

based on the phase information, a displacement of a mechanical member relative to the resonant sensor is determined, wherein the displacement of the mechanical member causes a change in an impedance of the resonant sensor.

18. A method comprising, in a system comprising a resistive-inductive-capacitive sensor and a driver configured to drive the resistive-inductive-capacitive sensor at a drive frequency:

determining a measured change in a resonant frequency of the resistive-inductive-capacitive sensor; and

modifying the drive frequency based on the measured change.

19. The method of claim 18, further comprising:

measuring at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor; and

determining the measured change in the resonant frequency of the resistive-inductive-capacitive sensor based on at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor.

20. The method of claim 19, further comprising:

measuring at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor; and

modifying the drive frequency when a change in at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor exceeds a threshold.

21. The method of claim 20, wherein the threshold value is based on a quality factor of the resistive-inductive-capacitive sensor.

22. The method of claim 18, further comprising modifying the drive frequency when the measured change exceeds a threshold.

23. The method of claim 22, wherein the threshold value is based on a quality factor of the resistive-inductive-capacitive sensor.

24. The method of claim 18, further comprising estimating a quality factor of the resistive-inductive-capacitive sensor.

25. The method of claim 24, further comprising estimating the quality factor based on at least one of phase information associated with the resistive-inductive-capacitive sensor and amplitude information associated with the resistive-inductive-capacitive sensor.

26. The method of claim 24, further comprising modifying the drive frequency based on the quality factor.

27. The method of claim 18, further comprising modifying the drive frequency by:

determining a change in phase information associated with the resistive-inductive-capacitive sensor; and

adjusting the drive frequency by a frequency change based on the phase information of the resistive-inductive-capacitive sensor and a slope of a phase versus frequency curve.

28. The method of claim 27, further comprising calculating the frequency change to be equal to the change in the phase information divided by the slope.

29. The method of claim 28, further comprising:

estimating a quality factor of the resistive-inductive-capacitive sensor; and

calculating the slope based on the quality factor.

30. The method of claim 18, further comprising modifying the drive frequency to match a resonant frequency of the resistive-inductive-capacitive sensor.

31. The method of claim 18, further comprising verifying that the modification to the drive frequency causes the drive frequency to match a resonant frequency of the resistive-inductive-capacitive sensor.

32. The method of claim 18, further comprising modifying the drive frequency such that the system operates in a linear region of a phase versus frequency curve of the resistance-inductance-capacitance sensor.

33. The method of claim 18, further comprising:

blanking measurement is performed on the phase information of the resistance-inductance-capacitance sensor in a measurement period after the drive frequency is modified; and

ensuring that the phase information changes caused by the modification of the drive frequency are not communicated to downstream processing.

34. The method of claim 18, further comprising:

measuring phase information associated with the resistive-inductive-capacitive sensor; and

based on the phase information, a displacement of a mechanical member relative to the resonant sensor is determined, wherein the displacement of the mechanical member causes a change in an impedance of the resonant sensor.

Technical Field

The present disclosure relates generally to electronic devices (e.g., mobile devices, game controllers, instrument panels for vehicles, machinery, and/or appliances, etc.) having user interfaces, and more particularly to resonant phase sensing of resistive-inductive-capacitive sensors used to replace mechanical buttons in systems in mobile devices and/or other suitable applications.

Background

Many conventional mobile devices (e.g., mobile phones, personal digital assistants, video game controllers, etc.) include mechanical buttons to allow interaction between a user of the mobile device and the mobile device itself. However, such mechanical buttons are susceptible to aging, wear and tear, which may shorten the useful life of the mobile device and/or may require extensive repair if malfunctioning. Moreover, the presence of mechanical buttons may make it difficult to manufacture a waterproof mobile device. Accordingly, mobile device manufacturers are increasingly looking to equip mobile devices with virtual buttons that act as a human machine interface that allows interaction between the user of the mobile device and the mobile device itself. Similarly, mobile device manufacturers are increasingly looking to equip mobile devices with other virtual interface areas (e.g., virtual sliders, interface areas of the mobile device body other than a touch screen, etc.). Ideally, for an optimal user experience, such a virtual interface area should look and feel to the user as if there were a mechanical button or other mechanical interface instead of a virtual button or virtual interface area.

Currently, Linear Resonant Actuators (LRAs) and other vibratory actuators (e.g., rotary actuators, vibratory motors, etc.) are increasingly used in mobile devices to generate vibratory feedback in response to user interaction with the human-machine interface of such devices. Typically, a sensor (traditionally a force or pressure sensor) detects a user interaction with the device (e.g., a finger press on a virtual button of the device), and in response thereto, the linear resonant actuator may vibrate to provide feedback to the user. For example, the linear resonant actuator may vibrate in response to a user's interaction with the human-machine interface to mimic the sensation of a mechanical button click to the user.

However, the industry requires sensors to detect user interaction with the human-machine interface, where such sensors provide acceptable levels of sensor sensitivity, power consumption, and size.

Disclosure of Invention

In accordance with the teachings of the present disclosure, disadvantages and problems associated with sensing human-machine interface interactions in mobile devices may be reduced or eliminated.

According to an embodiment of the present disclosure, a system may include: a resistive-inductive-capacitive sensor; a driver configured to drive the resistive-inductive-capacitive sensor at a drive frequency; and a measurement circuit communicatively coupled to the resistance-inductance-capacitance sensor and configured to determine a measured change in the resonant frequency of the resistance-inductance-capacitance sensor and modify the drive frequency based on the measured change.

In accordance with these and other embodiments of the present disclosure, a method may include: in a system including a resistive-inductive-capacitive sensor and a driver configured to drive the resistive-inductive-capacitive sensor at a drive frequency, a measured change in a resonant frequency of the resistive-inductive-capacitive sensor is determined, and the drive frequency is modified based on the measured change.

The technical advantages of the present disclosure will be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein. The objects and advantages of the embodiments will be realized and attained by at least the elements, features, and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the claims as set forth in this disclosure.

Drawings

A more complete understanding of embodiments of the present invention and the advantages thereof may be acquired by referring to the following description in consideration with the accompanying drawings, in which like reference numbers indicate like features, and wherein:

FIG. 1 illustrates a block diagram of selected components of an example mobile device, in accordance with embodiments of the present disclosure;

FIG. 2 illustrates a mechanical component spaced a distance from an inductor coil according to an embodiment of the present disclosure;

FIG. 3 illustrates selected components of a model of a mechanical member and an inductive coil that may be used in an inductive sensing system according to an embodiment of the disclosure;

4A-4C each show a diagram of selected components of an example resonant phase sensing system, in accordance with embodiments of the present disclosure;

FIG. 5 shows a diagram of selected components of an example resonant phase sensing system implementing a time division multiplexed processing of multiple resistive-inductive-capacitive sensors, in accordance with an embodiment of the present disclosure;

FIG. 6 illustrates an example graph of phase versus drive frequency for a resistive-inductive-capacitive sensor according to an embodiment of this disclosure;

FIG. 7 illustrates a block diagram of selected components of an example control circuit of a resonant phase sensing system, in accordance with embodiments of the present disclosure; and

FIG. 8 shows a flowchart of an example method for automatically centering a sensor frequency of a resonant sensor, in accordance with an embodiment of the present disclosure.

Detailed Description

FIG. 1 illustrates a block diagram of selected components of an example mobile device 102, in accordance with embodiments of the present disclosure. As shown in fig. 1, mobile device 102 may include a housing 101, a controller 103, a memory 104, a mechanical member 105, a microphone 106, a linear resonant actuator 107, a radio transmitter/receiver 108, a speaker 110, and a resonant phase sensing system 112.

The housing 101 may include any suitable shell, packaging, or other housing for housing the various components of the mobile device 102. The housing 101 may be constructed of plastic, metal, and/or any other suitable material. In addition, the housing 101 may be adapted (e.g., sized and shaped) such that the mobile device 102 is easily carried on a person of a user of the mobile device 102. Thus, the mobile device 102 may include, but is not limited to, a smart phone, a tablet computing device, a handheld computing device, a personal digital assistant, a notebook computer, a video game controller, or any other device that is readily carried on a person of a user of the mobile device 102.

Controller 103 may be housed within housing 101 and may include any system, device, or apparatus configured to interpret and/or execute program instructions and/or process data and may include, but is not limited to, a microprocessor, microcontroller, Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), or any other digital or analog circuitry configured to interpret and/or execute program instructions and/or process data. In some embodiments, the controller 103 may interpret and/or execute program instructions and/or process data stored in the memory 104 and/or other computer-readable media accessible to the controller 103.

The memory 104 may be housed within the housing 101, may be communicatively coupled to the controller 103, and may include any system, apparatus, or device (e.g., a computer-readable medium) configured to retain program instructions and/or data for a period of time. Memory 104 may include any suitable selection and/or array of Random Access Memory (RAM), electrically erasable programmable read-only memory (EEPROM), international personal computer memory card association (PCMCIA) cards, flash memory, magnetic storage devices, electro-optical storage devices, or volatile or non-volatile memory that retains data after power is turned off to mobile device 102.

The microphone 106 may be at least partially housed in the housing 101, may be communicatively coupled to the controller 103, and may include any system, device, or apparatus configured to convert sound incident at the microphone 106 into electrical signals that may be processed by the controller 103, wherein such sound is converted into electrical signals using a diaphragm or membrane having a capacitance that varies based on sound vibrations received at the diaphragm or membrane. The microphone 106 may include an electrostatic microphone, a capacitive microphone, an electret microphone, a microelectromechanical system (MEM) microphone, or any other suitable capacitive microphone.

The radio transmitter/receiver 108 may be housed within the housing 101, may be communicatively coupled to the controller 103, and may include any system, apparatus, and device configured to generate and transmit radio frequency signals by way of an antenna and receive radio frequency signals and convert information carried by such received signals into a form usable by the controller 103. The radio transmitter/receiver 108 may be configured to transmit and/or receive various types of radio frequency signals, including, but not limited to, cellular communications (e.g., 2G, 3G, 4G, LTE, etc.), short-range wireless communications (e.g., bluetooth), commercial radio signals, television signals, satellite radio signals (e.g., GPS), wireless fidelity, etc.

The speaker 110 may be housed at least partially within the housing 101 or may be external to the housing 101, may be communicatively coupled to the controller 103, and may include any system, apparatus, or device configured to produce sound in response to an electrical audio signal input. In some embodiments, the speaker may comprise a dynamic speaker employing a lightweight diaphragm mechanically coupled to a rigid frame via a flexible suspension that constrains the voice coil from moving axially through the cylindrical magnetic gap. When an electrical signal is applied to the voice coil, the current in the voice coil generates a magnetic field, making it a variable electromagnet. The magnetic system of the voice coil and driver interact, generating a mechanical force that moves the voice coil (and thus the attached cone) back and forth, reproducing sound under the control of an applied electrical signal from an amplifier.

The mechanical member 105 may be housed within or on the housing 101 and may include any suitable system, apparatus, or device configured to cause all or a portion of the mechanical member 105 to displace into place in response to a force, pressure, or touch applied on or near the mechanical member 105. In some embodiments, the mechanical feature 105 may be designed to appear as a mechanical button on the exterior of the housing 101.

The linear resonant actuator 107 may be housed within the housing 101 and may comprise any suitable system, device, or apparatus for generating an oscillating mechanical force across a single axis. For example, in some embodiments, the linear resonant actuator 107 may rely on an alternating voltage to drive a voice coil that is pressed against a moving mass connected to a spring. When the voice coil is driven at the resonant frequency of the spring, the linear resonant actuator 107 may vibrate with an appreciable force. Thus, the linear resonant actuator 107 may be useful in haptic applications in a particular frequency range. Although the present disclosure is described with respect to the use of a linear resonant actuator 107 for purposes of clarity and illustration, it should be understood that any other type or types of vibratory actuators (e.g., eccentric rotating mass actuators) may be used in place of or in addition to the linear resonant actuator 107. Additionally, it should also be understood that an actuator arranged to generate an oscillating mechanical force across multiple axes may be used instead of, or in addition to, linear resonant actuator 107. Based on the signals received from the resonant phase sensing system 112, the linear resonant actuator 107 can present haptic feedback to a user of the mobile device 102 for at least one of mechanical button replacement and capacitive sensor feedback, as described elsewhere in this disclosure.

The mechanical member 105 and the linear resonant actuator 107 may together form a human-machine interface device, such as a virtual interface (e.g., a virtual button) that has the look and feel of a mechanical button or other mechanical interface of the mobile device 102 to a user of the mobile device 102.

The resonant phase sensing system 112 may be housed within the housing 101, may be communicatively coupled to the mechanical member 105 and the linear resonant actuator 107, and may include any system, device, or apparatus configured to detect displacement of the mechanical member 105 (e.g., by a user of the mobile device 102) indicative of a physical interaction (e.g., a force applied by a human finger to a virtual interface of the mobile device 102) with a human-machine interface of the mobile device 102 (e.g., a force applied by a human finger to a virtual interface of the mobile device 102). As described in more detail below, the resonant phase sensing system 112 may detect displacement of the mechanical member 105 by performing resonant phase sensing of a resistive-inductive-capacitive sensor for changes in impedance (e.g., inductance, capacitance, and/or resistance) of the resistive-inductive-capacitive sensor in response to the displacement of the mechanical member 105. Accordingly, mechanical member 105 may comprise any suitable system, device, or apparatus, all or a portion of which may be displaced, and such displacement may cause a change in the impedance of a resistive-inductive-capacitive sensor integrated into resonant phase sensing system 112. The resonant phase sensing system 112 may also generate an electronic signal for driving the linear resonant actuator 107 in response to a physical interaction associated with a human-machine interface associated with the mechanical member 105. Details of an example resonant phase sensing system 112 according to embodiments of the present disclosure will be described in detail below.

Although certain example components are depicted above in fig. 1 as being integrated into the mobile device 102 (e.g., the controller 103, the memory 104, the mechanical structure 105, the microphone 106, the radio transmitter/receiver 108, the speaker(s) 110, the linear resonant actuator 107, etc.), the mobile device 102 in accordance with the present disclosure may include one or more components not specifically listed above. For example, although fig. 1 depicts certain user interface components, the mobile device 102 may include one or more other user interface components in addition to those depicted in fig. 1, including but not limited to a keypad, a touchscreen, and a display, thus allowing a user to interact with and/or otherwise manipulate the mobile device 102 and its associated components. Additionally, although fig. 1 depicts only a single virtual button including the mechanical member 105 and the linear resonant actuator 107 for purposes of clarity and illustration, in some embodiments, the mobile device 102 may have multiple virtual interfaces, each including a respective mechanical member 105 and linear resonant actuator 107.

Although, as described above, the resonant phase sensing system 112 may detect the displacement of the mechanical member 105 by performing resonant phase sensing of a resistive-inductive-capacitive sensor for changes in the impedance (e.g., inductance, capacitance, and/or resistance) of the resistive-inductive-capacitive sensor in response to the displacement of the mechanical member 105, in some embodiments, the resonant phase sensing system 112 may detect the displacement of the mechanical member 105 primarily by determining changes in the inductance of the resistive-inductive-capacitive sensor using resonant phase sensing. For example, fig. 2 and 3 illustrate selected components of an example inductive sensing application that may be implemented by the resonant phase sensing system 112, according to an embodiment of the present disclosure.

Although the foregoing contemplates the resonant phase sensing system 112 being used in the mobile device 102, the resonant phase sensing system 112 may be used in any other suitable host device. Host devices may include, but are not limited to, portable and/or battery-powered mobile computing devices (e.g., laptop, notebook, or tablet computers), game controllers, remote control devices, home automation controllers, home appliances (e.g., home temperature or lighting control systems), toys, machines (e.g., robots), audio players, video players, and mobile phones (e.g., smartphones).

Fig. 2 shows a mechanical component 105 implemented as a metal plate spaced a distance d from an inductor 202, according to an embodiment of the disclosure. Fig. 3 illustrates selected components of a model of a mechanical structure 105 and an inductive coil 202 that may be used in an inductive sensing system 300 according to an embodiment of the disclosure. As shown in fig. 3, inductive sensing system 300 may include mechanical member 105 modeled as a variable resistance 304 and a variable inductance 306, and may include inductive coil 202 physically proximate to mechanical member 105 such that inductive coil 202 has a mutual inductance with mechanical member 105, which is defined by a variable coupling coefficient k. As shown in fig. 3, the inductive coil 202 may be modeled as a variable inductance 308 and a variable resistance 310.

In operation, when a current I flows through the induction coil 202, this current may induce a magnetic field, which in turn may induce eddy currents inside the mechanical member 105. When a force is applied to the mechanical member 105 and/or removed from the mechanical member 105, which changes the distance d between the mechanical member 105 and the inductive coil 202, the coupling coefficient k, the variable resistance 304, and/or the variable inductance 306 may also change in response to the change in distance. These changes in the various electrical parameters may, in turn, modify the effective impedance Z of the inductive coil 202_L。

FIG. 4A shows a diagram of selected components of an example resonant phase sensing system 112A, according to an embodiment of the present disclosure. In some embodiments, the resonant phase sensing system 112A can be used to implement the resonant phase sensing system 112 of fig. 1. As shown in fig. 4A, the resonant phase sensing system 112A may include a resistive-inductive-capacitive sensor 402 and a processing Integrated Circuit (IC) 412A.

As shown in fig. 4A, a resistive-inductive-capacitive sensor 402 may include a mechanical member 105, an inductive coil 202, a resistor 404, and a capacitor 406, where the mechanical member 105 and the inductive coil 202 have a variable coupling coefficient k. Although shown in fig. 4A as being arranged in parallel with one another, it should be understood that inductive coil 202, resistor 404, and capacitor 406 may be arranged in any other suitable manner that allows resistive-inductive-capacitive sensor 402 to act as a resonant tank. For example, in some embodiments, inductive coil 202, resistor 404, and capacitor 406 may be arranged in series with one another. In some embodiments, resistor 404 may not be implemented as a separate resistor, but may instead be implemented by a parasitic resistance of inductive coil 202, a parasitic resistance of capacitor 406, and/or any other suitable parasitic resistance.

The processing IC412A may be communicatively coupled to the resistive-inductive-capacitive sensor 402 and may include any suitable system, apparatus, or device configured to implement measurement circuitry to measure phase information associated with the resistive-inductive-capacitive sensor 402 and determine a displacement of the mechanical member 105 relative to the resistive-inductive-capacitive sensor 402 based on the phase information. Accordingly, the processing IC412A may be configured to determine, based on the phase information, an occurrence of a physical interaction (e.g., pressing or releasing a virtual button) associated with a human-machine interface associated with the mechanical member 105.

As shown in fig. 4A, the processing IC412A may include a phase shifter 410, a voltage-to-current converter 408, a preamplifier 440, an intermediate frequency mixer 442, a combiner 444, a Programmable Gain Amplifier (PGA)414, an oscillator 416, a phase shifter 418, an amplitude and phase calculation block 431, a DSP 432, a low pass filter 434, a combiner 450, and a control circuit 452. The processing IC412A may also include a coherent incident/quadrature detector implemented in an incident channel including a mixer 420, a low pass filter 424, and an analog-to-digital converter (ADC)428, and a quadrature channel including a mixer 422, a low pass filter 426, and an ADC430, such that the processing IC412A is configured to measure phase information using the coherent incident/quadrature detector.

Phase shifter 410 may comprise any system, device, or apparatus configured to receive an oscillating signal generated by processing IC412A (as explained in more detail below) and phase shift such oscillating signal based on a control signal phaasedjust received from control circuit 452 such that an incident component of sensor signal phi generated by preamplifier 440 is approximately equal to a quadrature component of sensor signal phi at an operating frequency of resonant phase sensing system 112, thereby providing common mode noise rejection by a phase detector implemented by processing IC412A, as described in more detail below.

The voltage-to-current converter 408 may receive the phase-shifted oscillating signal, which may be a voltage signal, from the phase shifter 410, convert the voltage signal to a corresponding current signal, and drive the current signal at the same drive frequency as the phase-shifted oscillating signal on the resistive-inductive-capacitive sensor 402 to generate a sensor signal φ that may be processed by the processing IC412A, as described in more detail below. In some embodiments, the drive frequency of the phase-shifted oscillating signal may be selected based on the resonant frequency of the resistive-inductive-capacitive sensor 402 (e.g., may be approximately equal to the resonant frequency of the resistive-inductive-capacitive sensor 402).

The preamplifier 440 may receive the sensor signal φ and the status sensor signal φ for mixing with the mixer 442 to an intermediate frequency Δ f that is combined by the combiner 444 and the oscillation frequency generated by the oscillator 416, as described in more detail below, wherein the intermediate frequency Δ f is substantially less than the oscillation frequency. In some embodiments, the preamplifier 440, mixer 442, and combiner 444 may not be present, in which case the PGA 414 may receive the sensor signal phi directly from the rc sensor 402. However, when present, the preamplifier 440, mixer 442, and combiner 444 may allow the sensor signal φ to be mixed down to a lower intermediate frequency Δ f, which may allow for lower bandwidth and more efficient ADCs (e.g., ADCs 428 and 430 of FIGS. 4A and 4B and ADC 429 of FIG. 4C, as described below), and/or which may allow for minimizing phase and/or gain mismatches in the incident and quadrature paths of the phase detector of the processing IC 412A.

In operation, the PGA 414 may further amplify the sensor signal φ to condition the sensor signal φ for processing by the coherent incident/quadrature detector. The oscillator 416 may generate an oscillating signal to be used as a basis for the signal driven by the voltage-to-current converter 408, as well as an oscillating signal used by the mixers 420 and 422 to provide incident and quadrature components of the amplified sensor signal phi. As shown in fig. 4A, mixer 420 of the incident channel may use an unshifted version of the oscillating signal generated by oscillator 416, while mixer 422 of the quadrature channel may use a 90 degree shifted version of the oscillating signal phase shifted by phase shifter 418. As described above, the oscillation frequency of the oscillating signal generated by the oscillator 416 may be selected based on the resonant frequency of the resistive-inductive-capacitive sensor 402 (e.g., may be approximately equal to the resonant frequency of the resistive-inductive-capacitive sensor 402). Thus, as described in more detail below, the control circuit 452 may generate an indication oscillation frequency f₀And transmits the control signal to the oscillator 416 so as to cause the oscillator 416 to oscillate at the oscillation frequency f₀An oscillating signal is generated.

In some embodiments, the oscillator 416 may be implemented with a Voltage Controlled Oscillator (VCO), in which case the control circuit 452 may generate the indication oscillation frequency f₀As a control signal to the oscillator 416. In other embodiments, the oscillator 416 may be implemented using a Digitally Controlled Oscillator (DCO), in which case the control circuit 452 may generate the indication oscillation frequency f₀As a control signal to the oscillator 416.

In the incident channel, mixer 420 may extract an incident component of the amplified sensor signal φ, low pass filter 424 may filter the oscillating signal mixed with the amplified sensor signal φ to generate a Direct Current (DC) incident component, and ADC428 may convert this DC incident component to an equivalent incident component digital signal for processing by amplitude and phase calculation module 431. Similarly, in the quadrature channel, mixer 422 may extract the quadrature component of the amplified sensor signal φ, low pass filter 426 may filter out the phase-shifted oscillator signal mixed with the amplified sensor signal φ to generate a Direct Current (DC) quadrature component, and ADC430 may convert this DC quadrature component to an equivalent quadrature component digital signal for processing by amplitude and phase calculation block 431.

Amplitude and phase calculation block 431 may comprise any system, apparatus, or device configured to receive a phase information comprising an incident component digital signal and a quadrature component digital signal, and extract amplitude and phase information based thereon.

DSP 432 may include any system, apparatus, or device configured to interpret and/or execute program instructions and/or process data. In particular, the DSP 432 may receive the phase information and the amplitude information generated by the amplitude and phase calculation block 431 and determine, based on the information, a displacement of the mechanical member 105 relative to the resistive-inductive-capacitive sensor 402, which may indicate an occurrence of a physical interaction (e.g., pressing or releasing a virtual button or other interaction with a virtual interface) associated with a human-machine interface associated with the mechanical member 105 based on the phase information. The DSP 432 may also generate an output signal indicative of the displacement. In some embodiments, this output signal may comprise a control signal for controlling the mechanical vibration of the linear resonant actuator 107 in response to the displacement.

The combiner 450 may be derived from the reference phase phi_refThe phase information generated by the amplitude and phase calculation block 431 is subtracted to generate an error signal that can be received by the low pass filter 434. The low pass filter 434 may low pass filter the error signal and may apply this filtered error signal to the oscillator 416 to modify the frequency of the oscillating signal generated by the oscillator 416 to move the sensor signal φ toward the reference phase φ_refAnd (5) driving. As a result, in response to a "press" of a virtual button (or other interaction with a virtual interface) associated with the resonant phase sensing system 112A, the sensor signal φ may include a transient decay signal, and in response to a subsequent "release" of the virtual button (or other interaction with the virtual interface)Other interactions of facets) attenuates the signal. Thus, the low pass filter 434 connected to the oscillator 416 may implement a feedback control loop that may track changes in the operating parameters of the resonant phase sensing system 112A by modifying the drive frequency of the oscillator 416.

The control circuit 452 may include a circuit configured to generate a control signal indicative of a PHASE shift PHASE ADJUST and indicative of an oscillation frequency f₀Any suitable system, device or apparatus for controlling signals. As described above, the control circuit 452 may oscillate the frequency f₀Is set approximately equal to the resonant frequency of the resistive-inductive-capacitive sensor 402. Accordingly, as described below, the control circuit 452 may be configured to determine a resonant frequency of the resistive-inductive-capacitive sensor 402 during operation of the resonant phase sensing system 112A in order to modify this resonant frequency due to external parameters of the resistive-inductive-capacitive sensor 402, including but not limited to the sensor temperature, the distance d between the mechanical member 105 and the inductive coil 202 (e.g., due to aging or virtual button presses), and/or external interference signals.

FIG. 4B shows a diagram of selected components of an example resonant phase sensing system 112B, according to an embodiment of the present disclosure. In some embodiments, the resonant phase sensing system 112B can be used to implement the resonant phase sensing system 112 of fig. 1. In many respects, the resonant phase-sensing system 112B of fig. 4B can be similar to the resonant phase-sensing system 112A of fig. 4A. Accordingly, only those differences between the resonant phase sensing system 112B and the resonant phase sensing system 112A may be described below. As shown in fig. 4B, the resonant phase sensing system 112B may include a processing IC412B in place of the processing IC 412A. In many respects, the processing IC412B of fig. 4B may be similar to the processing IC412A of fig. 4A. Accordingly, only those differences between processing IC412B and processing IC412A may be described below.

The processing IC412B may include a variable phase shifter 419. Thus, in operation, oscillator 416 may drive a drive signal and an oscillation signal, and variable phase shifter 419 may phase shift to generate an oscillation signal to be mixed by mixers 420 and 422. Similar to processing IC412A, low pass filter 434 may low pass filter the error signal based on the phase information extracted by amplitude and phase calculation module 431, but may instead apply this filtered error signal to variable phase shifter 419 to modify the phase offset of the oscillating signal generated by oscillator 416 so as to drive the sensor signal Φ toward an indicated phase shift of zero. As a result, the sensor signal Φ can include a transient decay signal in response to a "press" of a virtual button (or other interaction with the virtual interface) associated with the resonant phase sensing system 112B and another transient decay signal in response to a subsequent "release" of the virtual button (or other interaction with the virtual interface). Accordingly, the low pass filter 434 connected to the variable phase shifter 419 may implement a feedback control loop that may track changes in the operating parameters of the resonant phase sensing system 112B by modifying the phase shift applied by the variable phase shifter 419.

Fig. 4C shows a diagram of selected components of an example resonant phase sensing system 112C, in accordance with an embodiment of the present disclosure. In some embodiments, the resonant phase sensing system 112C can be used to implement the resonant phase sensing system 112 of fig. 1. In many respects, the resonant phase-sensing system 112C of fig. 4C can be similar to the resonant phase-sensing system 112A of fig. 4A. Accordingly, only those differences between the resonant phase sensing system 112C and the resonant phase sensing system 112A may be described below. For example, a particular difference between resonant phase sensing system 112C and resonant phase sensing system 112A is that resonant phase sensing system 112C may include ADC 429 in place of ADC428 and ADC 430. Thus, a coherent incident/quadrature detector for resonant phase sensing system 112C may be implemented with an incident channel including a digital mixer 421 and a digital low pass filter 425 (instead of analog mixer 420 and analog low pass filter 424) and a quadrature channel including a digital mixer 423 and a low pass filter 427 (instead of analog mixer 422 and analog low pass filter 426), such that processing IC 412C is configured to measure phase information using such a coherent incident/quadrature detector. Although not explicitly shown, the resonant phase sensing system 112B can be modified in a manner similar to how the resonant phase sensing system 112A is shown to be modified to produce the resonant phase sensing system 112C.

Fig. 5 shows a diagram of selected components of an example resonant phase sensing system 112D that implements a time-multiplexed processing of a plurality of resistive-inductive-capacitive sensors 402 (e.g., resistive-inductive-capacitive sensors 402A-402N shown in fig. 5), according to an embodiment of the disclosure. In some embodiments, the resonant phase sensing system 112D may be used to implement the resonant phase sensing system 112 of fig. 1. In many respects, the resonant phase-sensing system 112D of fig. 5 can be similar to the resonant phase-sensing system 112A of fig. 4A. Accordingly, only those differences between the resonant phase sensing system 112D and the resonant phase sensing system 112A may be described below. In particular, the resonant phase sensing system 112D may include a plurality of resistive-inductive-capacitive sensors 402 (e.g., resistive-inductive-capacitive sensors 402A-402N shown in fig. 5) instead of the single resistive-inductive-capacitive sensor 402 shown in fig. 4A. In addition, resonant phase sensing system 112D may include multiplexers 502 and 504, each of which may SELECT an output signal from a plurality of input signals in response to a control signal SELECT, which may be controlled by time division multiplexing control circuitry 552.

Control circuitry 552 may include any suitable system, apparatus, or device configured to control time division multiplexed sensing on one or more resistive-inductive-capacitive sensors 402, as described in more detail below. Although fig. 5 illustrates control circuitry 552 as being integrated with processing IC 412D, in some embodiments, control circuitry 552 may be implemented by controller 103 or another suitable component of mobile device 102.

Thus, although in some embodiments, a device such as mobile device 102 may include multiple resistive-inductive-capacitive sensors 402 that may be driven simultaneously and processed separately by a respective processing IC, in other embodiments, a resonant phase sensing system (e.g., resonant phase sensing system 112D) may drive resistive-inductive-capacitive sensors 402 in a time-multiplexed manner. Such an approach may reduce power consumption and device size compared to multi-sensor implementations in which multiple sensors are driven and/or sensed simultaneously. By time-multiplexing multiple sensors into a single driver and measurement circuit channel, the device size can be reduced, where only a single driver and a single measurement circuit may be required, thus minimizing the amount of integrated circuit area required to perform the driving and measurement. In addition, by utilizing a single driver and measurement circuit, calibration may not be required to accommodate mismatches and/or errors between different drivers and/or different measurement circuits.

For clarity and illustration, preamplifier 440, mixer 442 and combiner 444 are excluded from fig. 5. However, in some embodiments, the processing IC 412D may include a preamplifier 440, a mixer 442, and a combiner 444 similar to those depicted in fig. 4A-4C.

In resonant phase sensing system 112D, control circuitry 552 may provide control of control signal SELECT to SELECT a first resistive-inductive-capacitive sensor (e.g., resistive-inductive-capacitive sensor 402A) to be driven by voltage-to-current converter 408 and measured by measurement circuitry implemented by processing IC 412D for a first duration of a scan cycle. During this first duration, control circuitry 552 may place the resistive-inductive-capacitive sensors other than resistive-inductive-capacitive sensor 402A in a low impedance state. Similarly, during the second duration of the scan period, control circuitry 552 may provide control of control signal SELECT to SELECT a second resistive-inductive-capacitive sensor (e.g., resistive-inductive-capacitive sensor 402B) to be driven by voltage-to-current converter 408 and measured by measurement circuitry implemented by processing IC 412D. During this second duration, control circuitry 552 may place the resistive-inductive-capacitive sensors other than resistive-inductive-capacitive sensor 402B in a low impedance state. A similar process may allow other resistive-inductive-capacitive sensors 402 to be sensed during other durations of the scanning period. This approach may minimize power consumption within unselected resistive-inductive-capacitive sensors 402.

Although not explicitly shown, the resonant phase sensing system 112B can be modified in a manner similar to how the resonant phase sensing system 112A is shown modified to produce the resonant phase sensing system 112D, such that the resonant phase sensing system 112B can implement time-multiplexed sensing over the plurality of resistive-inductive-capacitive sensors 402. Similarly, although not explicitly shown, the resonant phase sensing system 112C can be modified in a manner similar to how the resonant phase sensing system 112A is shown modified to produce the resonant phase sensing system 112D, such that the resonant phase sensing system 112C can implement time-multiplexed sensing over the plurality of resistive-inductive-capacitive sensors 402.

FIG. 6 illustrates phase φ versus drive frequency f for a resistive-inductive-capacitive sensor 402 in accordance with an embodiment of the disclosure₀Example graph of (a). As shown in FIG. 6, the nominal operating frequency f is selected for the oscillator 416_nomTo operate at or near the resonant frequency of the rc sensor 402 so as to operate in phase phi versus the drive frequency f₀In the linear region of (a). In which the phase phi follows the drive frequency f₀Approximately linearly. Operation in this range ensures that any change in the inductance of the RC sensor 402 is reflected in a change in phase phi proportionally to the drive frequency f₀The slope of (a). At drive frequencies f too far from the resonant frequency₀Operating down and in the non-linear region of the phase-frequency curve may result in a small phase change (in terms of inductance change) and therefore reduced measurement sensitivity. Therefore, operation in the non-linear range may be sub-optimal and therefore undesirable.

Although the driving frequency f can be adjusted₀Initially set to a nominal operating frequency f_nomHowever, the resonant frequency of the rc sensor 402 may change due to the pressing of a virtual button on the rc sensor 402, the sensor temperature, the distance d between the mechanical member 105 and the induction coil 202 (e.g., due to aging), and/or external interference signals. In some cases, such a change in resonant frequency may cause the nominal operating frequency f_nomIs very different from the resonance frequency, resulting in secondary frequencies in the non-linear region of the phase vs. frequency curve of the resistance-inductance-capacitance sensorAn optimization operation 402.

FIG. 7 illustrates a block diagram of selected components of an example control circuit 452 of the resonant phase sensing system 112, according to an embodiment of the present disclosure. As shown in fig. 7, the control circuit 452 may include a resonance monitor 702, a quality (Q) factor estimator 704, a frequency variation calculator 706, and a phase adjustment block 708. In some embodiments, some or all of the functions of the control circuit 452 may be performed by the DSP 432.

The resonance monitor 702 may include a drive frequency f configured to vary from exceeding a threshold value₀Any system, device, or apparatus that detects a change in resonance of the resistive-inductive-capacitive sensor 402.

Q-factor estimator 704 may include any system, apparatus, or device configured to estimate a quality (Q) factor of resistive-inductive-capacitive sensor 402 based on phase information and/or based on amplitude information associated with resistive-inductive-capacitive sensor 402. For example, the Q factor may be estimated by measuring a change in phase versus frequency or a change in amplitude versus frequency. In some embodiments, the Q-factor estimator 704 may be implemented in a manner similar to that disclosed in U.S. patent application serial No. 16/294,217 filed on 6.3.2019, which is incorporated herein by reference in its entirety.

The frequency variation calculator 706 may include any system, apparatus, or device configured to drive the frequency f from the resonant frequency based on the signals output by the resonance monitor 702 and the Q-factor estimator 704₀Nominal frequency f required to be centered at the resonant frequency of the RC sensor 402_nomCalculating the frequency variation f_JUMP。

The phase adjustment block 708 may include any system, apparatus, or device configured to vary the phase based on the frequency f_JUMPAnd phase measurement information from DSP 432 to determine a phase adjustment to be applied by phase shifter 410 or phase shifter 419 to phase shift the oscillation signal generated by oscillator 416 such that at the drive frequency f of resonant phase sensing system 112₀Next, the incident component of the sensor signal φ generated by the preamplifier 440 is approximately equal to the quadrature component of the sensor signal φ for implementation by the processing IC412Provides common mode noise rejection.

The operation of the components of the control circuit 452 may be further illustrated with reference to fig. 8 and the following description thereof.

FIG. 8 shows a flowchart of an example method 800 for automatically centering a sensor frequency of a resonant sensor, in accordance with embodiments of the present disclosure. According to some embodiments, method 800 may begin at step 802. As noted above, the teachings of the present disclosure may be implemented in various configurations of the resonant phase sensing system 112. As such, the preferred initialization point for method 800 and the order in which the steps of method 800 are included may depend on the implementation chosen. In these and other embodiments, method 800 may be implemented as firmware, software, applications, functions, libraries, or other instructions.

At step 802, the resonance monitor 702 may monitor to determine the measured phase φ_measPhase difference phi between_diffFrom the initial phase phi_initIs greater than a threshold amount, wherein the initial phase phi_initAt a driving frequency f₀At a nominal frequency f_nomAnd is relative to a measurement phase phi that may occur when no interaction (e.g., virtual button press) occurs with the resistive-inductive-capacitive sensor 402. This threshold amount may be selected to be small enough that the automatic centering of the sensor frequency occurs before sub-optimal operation occurs outside the linear region of the phase versus frequency curve of the resistive-inductive-capacitive sensor 402. In these and other embodiments, this threshold may be dynamically varied based on the sensor Q factor (e.g., for larger Q factors, the threshold may be higher). If the difference is Δ_diffGreater than the threshold amount, the method 800 may proceed to step 804. Otherwise, the method 800 may remain at step 802 until the difference Δ_diffGreater than a threshold amount.

Although the preceding paragraph envisions a phase difference Δ that would exceed a threshold value_diffAs a trigger to perform automatic centering, but instead of or in addition to the phase difference Δ_diffBeyond the threshold, one or more other triggers may be used, including but not limited to: external trigger signal, periodic automatic centering at a predetermined rate, Q factorExceeds a predetermined threshold, the phase difference phi_diffA threshold number of consecutive phase measurements, phase difference phi, exceeding its corresponding threshold value_diffExceed their respective thresholds for a threshold time period and/or phase difference phi_diffExceeds its corresponding threshold.

In step 804, the Q factor estimator 704 may estimate the Q factor for the rc sensor 402. For example, the Q-factor estimator 704 may be at two different drive frequencies f₀The phase phi is measured to estimate the Q factor.

In step 806, the frequency variation calculator 706 may drive the frequency f according to the driving frequency f₀Nominal frequency f required to be centered at the resonant frequency of the RC sensor 402_nomTo calculate the frequency variation f_JUMP. In some embodiments, the frequency may be varied by f_JUMPCalculated as the phase difference φ of the phase versus frequency curve of the resistive-inductive-capacitive sensor 402_diffAnd slope phi_slopeRatio of (d), slope phi_slopeMay be derived from the estimated Q factor. For example, this slope can be estimated as:

where Q is the estimated Q factor.

At step 808, the control circuit 452 may base on the nominal frequency f_nomAnd frequency variation f_JUMPGenerating a control signal to cause the oscillator 416 to drive at a frequency f₀＝f_nom+f_JUMPAnd (6) working. In embodiments in which the oscillator 416 is implemented by a VCO, the control circuit 452 may suitably vary the control voltage delivered to the oscillator 416 as a control signal such that the oscillator 416 outputs the drive frequency f₀＝f_nom+f_JUMP. In embodiments where the oscillator 416 is implemented by a DCO, the control circuit 452 may suitably alter the digital control code transmitted to the oscillator 416 as a control signal such that the oscillator 416 outputs the drive frequency f₀＝f_nom+f_JUMP。

In step 810, controlThe circuit 452 may be at the drive frequency f₀The measurement of phase phi is blanked for a period after the change occurs and it can be ensured that the change in phase information caused by the modification of the drive frequency is not passed to downstream processing (e.g., by holding the previously sampled measurement and passing the previously sampled measurement to downstream processing for a period) in order to prevent inconsistent phase information from being reported. After completing step 810, method 800 may again proceed to step 802.

Although fig. 8 discloses a particular number of steps to be taken with respect to method 800, method 800 may be performed with more or fewer steps than those depicted in fig. 8. For example, in some embodiments, method 800 may include the steps of: the verification period ensures that the automatically centered phase phi is close to its initial phase phi_init. In these and other embodiments, the method 800 may include the steps of: after automatic centering, additional Q factor estimation may be performed to ensure operation in the linear portion of the phase versus frequency curve of the resistive-inductive-capacitive sensor 402. In these and other embodiments, the method 800 may include one or more steps with calibrating the initial phase φ for parameter variations (e.g., temperature, mechanical deformation, etc.)_initThe period of (c).

Additionally, although FIG. 8 discloses some order of steps to be taken with respect to method 800, the steps comprising method 800 may be completed in any suitable order.

Method 800 may be implemented using resonant phase sensing system 112, components thereof, or any other system operable to implement method 800. In certain embodiments, the method 800 may be implemented, in part or in whole, in software and/or firmware embodied in a computer-readable medium.

Although the foregoing contemplates the use of closed loop feedback for sensing displacement, the various embodiments represented by fig. 4A-5 may be modified to implement an open loop system for sensing displacement. In this open loop system, the processing IC may not include a feedback path from the amplitude and phase calculation block 431 to the oscillator 416 or the variable phase shifter 419, and thus may also lack the feedback low pass filter 434. Thus, the phase measurement may still be achieved by comparing the phase change to a reference phase value, but may not modify the oscillation frequency driven by the oscillator 416, or may not phase shift the phase shifted by the variable phase shifter 419.

Although the foregoing contemplates using a coherent incident/quadrature detector as the phase detector for determining the phase information associated with resistive-inductive-capacitive sensor 402, resonant phase sensing system 112 may perform phase detection and/or otherwise determine the phase information associated with resistive-inductive-capacitive sensor 402 in any suitable manner, including but not limited to using only one of the incident path or the quadrature path to determine the phase information.

In some embodiments, the incident/quadrature detector disclosed herein may include one or more frequency conversion stages that convert the sensor signal directly to a direct current signal or to an intermediate frequency signal and then to a direct current signal. Any of such frequency conversion stages may be implemented digitally after the analog-to-digital converter stage or in analog before the analog-to-digital converter stage.

Additionally, while the foregoing contemplates measuring changes in resistance and inductance in the resistive-inductive-capacitive sensor 402 caused by displacement of the mechanical member 105, other embodiments may operate based on the following principles: any change in impedance based on the displacement of the mechanical member 105 may be used to sense the displacement. For example, in some embodiments, displacement of the mechanical member 105 may cause a change in the capacitance of the resistive-inductive-capacitive sensor 402, such as if the mechanical member 105 includes a metal plate implementing one of the capacitive plates of the capacitor 406.

Although the DSP 432 is capable of processing the phase information to make a binary determination as to whether a physical interaction associated with a human-machine interface associated with the mechanical member 105 has occurred and/or has ceased to occur, in some embodiments, the DSP 432 may vary the amount of time duration for which the mechanical member 105 is displaced to more than one detection threshold, for example, to detect different types of physical interactions (e.g., a short press of a virtual button versus a long press of a virtual button). In these and other embodiments, the DSP 432 may quantify the magnitude of the displacement to more than one detection threshold, for example, to detect different types of physical interactions (e.g., a light virtual button versus a quick and hard virtual button press).

As used herein, when two or more elements are referred to as being "coupled to" one another, this term indicates that the two or more elements are in electrical or mechanical communication (as applicable), whether indirectly connected or directly connected, with or without intervening elements.

The present disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Furthermore, references in the appended claims to an apparatus or system or a component of an apparatus or system being adapted for, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompass the apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, so long as the apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Thus, modifications, additions, or omissions may be made to the systems, devices, and methods described herein without departing from the scope of the disclosure. For example, components of the systems and devices may be integrated or separated. Moreover, the operations of the systems and devices disclosed herein may be performed by more, fewer, or other components, and the methods described may include more, fewer, or other steps. Additionally, the steps may be performed in any suitable order. As used in this document, "each" refers to each member of a set or each member of a subset of a set.

Although exemplary embodiments are illustrated in the accompanying drawings and described below, the principles of the disclosure may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the exemplary embodiments and techniques illustrated in the drawings and described above.

Unless specifically stated otherwise, the items depicted in the drawings are not necessarily drawn to scale.

All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the present disclosure and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Although the embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the disclosure.

Although specific advantages have been enumerated above, various embodiments may include some, none, or all of the enumerated advantages. In addition, other technical advantages will be readily apparent to one of ordinary skill in the art upon review of the foregoing figures and description.

To assist the patent office and any reader of any patent issued in accordance with this application in interpreting the appended claims of this application, applicants desire to note that they do not wish to refer to 35u.s.c. § 112(f) by any of the appended claims or claim elements unless the word "means for … …" or "step for … …" is explicitly used in a particular claim.