WO2022240475A1 - Position-sensing via impedance estimation of a multi-coil electro-mechanical actuator - Google Patents
Position-sensing via impedance estimation of a multi-coil electro-mechanical actuator Download PDFInfo
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- 238000006073 displacement reaction Methods 0.000 claims abstract description 62
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- 238000002847 impedance measurement Methods 0.000 description 33
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R29/00—Monitoring arrangements; Testing arrangements
- H04R29/001—Monitoring arrangements; Testing arrangements for loudspeakers
- H04R29/003—Monitoring arrangements; Testing arrangements for loudspeakers of the moving-coil type
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/282—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
- G01R31/2829—Testing of circuits in sensor or actuator systems
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/016—Input arrangements with force or tactile feedback as computer generated output to the user
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/007—Protection circuits for transducers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2400/00—Loudspeakers
- H04R2400/03—Transducers capable of generating both sound as well as tactile vibration, e.g. as used in cellular phones
Definitions
- the present disclosure relates in general to methods, apparatuses, or implementations for monitoring loads with complex impedances.
- Embodiments set forth herein may also disclose improvements to how a displacement of a haptic actuator or other electromechanical load may be sensed and/or improvements to how a complex impedance is monitored.
- An LRA may be modelled as a mass-spring electro-mechanical vibration system. When driven with appropriately designed or controlled driving signals, an LRA may generate certain desired forms of vibrations. For example, a sharp and clear- cut vibration pattern on a user’s finger may be used to create a sensation that mimics a mechanical button click. This clear-cut vibration may then be used as a virtual switch to replace mechanical buttons.
- FIGURE 1 illustrates an example of a vibro-haptic system in a device 100.
- Device 100 may comprise a controller 101 configured to control a signal applied to an amplifier 102.
- Amplifier 102 may then drive a vibrational actuator (e.g., haptic transducer) 103 based on the signal.
- Controller 101 may be triggered by a trigger to output to the signal.
- the trigger may, for example, comprise a pressure or force sensor on a screen or virtual button of device 100.
- tonal vibrations of sustained duration may play an important role to notify the user of the device of certain predefined events, such as incoming calls or messages, emergency alerts, and timer warnings, etc.
- the vibration resonance of the haptic transducer may vary from time to time.
- FIGURE 2 illustrates an example of a linear resonant actuator (LRA) modelled as a linear system.
- LRAs are non-linear components that may behave differently depending on, for example, the voltage levels applied, the operating temperature, and the frequency of operation. However, these components may be modelled as linear components within certain conditions.
- the LRA is modelled as a third order system having electrical and mechanical elements.
- Re and Le are the DC resistance and coil inductance of the coil-magnet system, respectively; and Bl is the magnetic force factor of the coil.
- the driving amplifier outputs the voltage waveform V (t) with the output impedance Ro.
- the terminal voltage V T (t) may be sensed across the terminals of the haptic transducer.
- the mass-spring system 201 moves with velocity u(t).
- a haptic system may require precise control of movements of the haptic transducer. Such control may rely on the magnetic force factor Bl, which may also be known as the electromagnetic transfer function of the haptic transducer.
- magnetic force factor Bl can be given by the product B . l, where B is magnetic flux density and / is a total length of electrical conductor within a magnetic field. Both magnetic flux density B and length / should remain constant in an ideal case with motion occurring along a single axis.
- an LRA may undergo displacement.
- displacement In order to protect an LRA from damage, such displacement may be limited. Accordingly, accurate measurement of displacement may be crucial in optimizing LRA displacement protection algorithms. Accurate measurement of displacement may also enable increased drive levels of the LRA. While existing approaches measure displacement, such approaches have disadvantages. For example, displacement may be measured using a Hall sensor, but Hall sensors are often costly to implement.
- a method may include applying a low-frequency actuation signal on an actuation coil of the electromagnetic actuator to drive mechanical displacement of the electromagnetic actuator, applying high-frequency electrical stimulus to a sensing coil of the electromagnetic actuator, and sensing a change in high-frequency impedance of the sensing coil in response to the high-frequency electrical stimulus over a full cycle of oscillation of the electromagnetic actuator.
- an integrated circuit may include one or more outputs configured to apply a low- frequency actuation signal on an actuation coil of the electromagnetic actuator to drive mechanical displacement of the electromagnetic actuator and apply high-frequency electrical stimulus to a sensing coil of the electromagnetic actuator, and sensing circuitry configured to sense a change in high-frequency impedance of the sensing coil in response to the high-frequency electrical stimulus over a full cycle of oscillation of the electromagnetic actuator.
- FIGURE 1 illustrates an example of a vibro-haptic system in a device, as is known in the art
- FIGURE 2 illustrates an example of a Linear Resonant Actuator (LRA) modelled as a linear system, as is known in the art;
- LRA Linear Resonant Actuator
- FIGURE 3 illustrates selected components of an example host device, in accordance with embodiments of the present disclosure
- FIGURE 4 illustrates selected components of an example impedance measurement subsystem, in accordance with embodiments of the present disclosure
- FIGURE 5 illustrates an example graph of high-frequency coil impedance of two electromagnetic coils versus a displacement x of a moving mass of an electromagnetic actuator, in accordance with embodiments of the present disclosure
- FIGURE 6 illustrates an example graph of high-frequency coil impedance of two electromagnetic coils versus a displacement x of a moving mass of an electromagnetic actuator, including excursion ranges of the two electromagnetic coils, in accordance with embodiments of the present disclosure
- FIGURE 7 illustrates an example graph of combined position-sensing impedance function of high-frequency coil impedance of two electromagnetic coils versus a displacement x of a moving mass of an electromagnetic actuator, in accordance with embodiments of the present disclosure
- FIGURE 9 illustrates a flow chart of an example method for calibration, in which calibration may be performed with simultaneous driving of actuation signals on two electromagnetic coils and simultaneous driving of pilot/test signals for sensing on both electromagnetic coils, in accordance with embodiments of the present disclosure
- FIGURE 10 illustrates a flow chart of an example method for calibration, in which calibration may be performed with time-multiplexed driving of actuation signals between two electromagnetic coils and simultaneous driving of pilot/test signals for sensing on both electromagnetic coils, in accordance with embodiments of the present disclosure
- Various electronic devices or smart devices may have transducers, speakers, and acoustic output transducers, for example any transducer for converting a suitable electrical driving signal into an acoustic output such as a sonic pressure wave or mechanical vibration.
- many electronic devices may include one or more speakers or loudspeakers for sound generation, for example, for playback of audio content, voice communications and/or for providing audible notifications.
- Such speakers or loudspeakers may comprise an electromagnetic actuator, for example a voice coil motor, which is mechanically coupled to a flexible diaphragm, for example a conventional loudspeaker cone, or which is mechanically coupled to a surface of a device, for example the glass screen of a mobile device.
- Some electronic devices may also include acoustic output transducers capable of generating ultrasonic waves, for example for use in proximity detection-type applications and/or machine- to-machine communication.
- an electronic device may additionally or alternatively include more specialized acoustic output transducers, for example, haptic transducers, tailored for generating vibrations for haptic control feedback or notifications to a user.
- an electronic device may have a connector, e.g., a socket, for making a removable mating connection with a corresponding connector of an accessory apparatus, and may be arranged to provide a driving signal to the connector so as to drive a transducer, of one or more of the types mentioned above, of the accessory apparatus when connected.
- Such an electronic device will thus comprise driving circuitry for driving the transducer of the host device or connected accessory with a suitable driving signal.
- the driving signal may generally be an analog time varying voltage signal, for example, a time varying waveform.
- an electromagnetic load may be driven by a driving signal V (t) to generate a sensed terminal voltage V T (t) across a coil of the electromagnetic load.
- Sensed terminal voltage V T (t) may be given by:
- V T (t) Z COIL I(t) + V B (t ) wherein /(t) is a sensed current through the electromagnetic load, ZCOIL is an impedance of the electromagnetic load, and V B (t ) is the back-electromotive force (back-EMF) associated with the electromagnetic load.
- back-EMF back-electromotive force
- an electromagnetic load means to generate and communicate an actuation signal to the electromagnetic load to cause displacement of a movable mass of the electromagnetic load. Further, to “drive” an electromagnetic load may also mean driving of a pilot signal or other test signal to the electromagnetic load from which electrical parameters of the electromagnetic load may be measured.
- back-EMF voltage V B (t) may be proportional to velocity of the moving mass of the electromagnetic load
- back-EMF voltage V B (t) may in turn provide an estimate of such velocity.
- Position of the moving mass may be related to an impedance of the electromagnetic load, including a coil inductance LCOIL of the electromagnetic load.
- back-EMF voltage V B (t) may become negligible and inductance may dominate the coil impedance Z COIL .
- Sensed terminal voltage V T@HF (t) at high frequencies may be estimated by:
- An inductance component of coil impedance ZCOIL may be indicative of a position or a displacement of the moving mass of the electromagnetic load. To illustrate, such inductance may be a nominal value when the moving mass is at rest.
- the magnetic field strength may be modulated by the position of the mass which leads to a small alternating-current (AC) modulation signal of the inductance that is a function of the mass position.
- AC alternating-current
- FIGURE 3 illustrates selected components of an example host device 300 having an electromagnetic actuator 304.
- Host device 300 may include, without limitation, a mobile device, home application, vehicle, and/or any other system, device, or apparatus that includes a human-machine interface.
- Electromagnetic actuator 304 may include any suitable load with a complex impedance, including without limitation a haptic transducer, a loudspeaker, a microspeaker, a voice-coil actuator, a solenoid, or other suitable transducer.
- a signal generator 324 of a processing subsystem 305 of host device 300 may generate a raw transducer driving signal x'(t) (which, in some embodiments, may be a waveform signal, such as a haptic waveform signal or audio signal).
- Raw transducer driving signal x'(t) may be generated based on a desired playback waveform received by signal generator 324.
- processed transducer driving signal x 2 (t) may in turn be amplified by amplifier 306b to generate a driving signal V 2 (t ) for driving electromagnetic load 301b.
- host device 300 may operate such that electromagnetic actuator 304 is altematingly driven by driving signal V 1 (t) and driving signal V 2 (t).
- host device 300 may operate in a series of alternating phases: a first phase in which driving signal V t (t) driven to electromagnetic load 301a drives electromagnetic actuator 304 and electromagnetic load 301b is used to measure a displacement of electromagnetic actuator 304, and a second phase in which driving signal V 2 (t) driven to electromagnetic load 301b drives electromagnetic actuator 304 and electromagnetic load 301a is used to measure a displacement of electromagnetic actuator 304.
- a sensed terminal voltage V T1 (t) of electromagnetic load 301a may be sensed by impedance measurement subsystem 308 (e.g., using a volt-meter).
- sensed current I t (t) through electromagnetic load 301a may be sensed by impedance measurement subsystem 308.
- current I 1 (t) may be sensed by a sense voltage V S1 ( t ) across a shunt resistor 302a having resistance R s coupled to a terminal of electromagnetic load 301a.
- a sensed terminal voltage V T2 (t) of electromagnetic load 301b may be sensed by impedance measurement subsystem 308 (e.g., using a volt-meter).
- sensed current / 2 (t) through electromagnetic load 301b may be sensed by impedance measurement subsystem 308.
- current / 2 (t) may be sensed by a sense voltage V S2 ( t ) across a shunt resistor 302b having resistance R s coupled to a terminal of electromagnetic load 301b.
- processing subsystem 305 may include an impedance measurement subsystem 308 that may estimate respective coil inductances LCOIL of electromagnetic loads 301a and 301b. From such estimated coil inductance LCOIL , impedance measurement subsystem 308 may determine a displacement associated with electromagnetic load 304. Based on such determined displacement, impedance measurement subsystem 308 may communicate one or more parameters to waveform preprocessor 326 (including, without limitation, the value of such displacement), which may cause waveform preprocessor 326 to modify raw transducer driving signal x (t). In some embodiments, such displacement may also be indicative of a human interaction (e.g., applied force) to electromagnetic actuator 304.
- waveform preprocessor 326 including, without limitation, the value of such displacement
- waveform preprocessor 326 may generate a processed transducer driving signal x 1 (t) or x 2 (t) (depending on which electromagnetic coil 301 is the actuating coil used to drive movement of electromagnetic load 304 and which electromagnetic coil 301 is used for sensing) comprising a high-frequency stimulus for driving the sensing coil.
- Such high- frequency stimulus may be a tone or a carrier signal (e.g., pulse-width modulation carrier for an amplifier 306).
- impedance measurement system 308 may measure impedance of the sensing coil.
- FIGURE 4 illustrates selected components of an example impedance measurement subsystem 308, in accordance with embodiments of the present disclosure.
- the digital representations of sensed voltage V s1 (t ) and sensed voltage V S2 (t) may be received by a multiplexer 408, which may select one of such digital representations based on a control signal SENSE_SELECT. Accordingly, multiplexer 408 will select the digital representation of the current through the electromagnetic load actively being used to perform sensing.
- impedance measurement subsystem 308 may perform parallel estimates of impedance based on sensed voltage V S1 (t) , sensed voltage V S2 (t) , sensed terminal voltage V T1 ( t ) , and sensed terminal voltage V T2 (t) .
- an inductance estimator 410 may estimate inductance L of the electromagnetic load actively being used to perform sensing. For example, inductance estimator 410 may calculate inductance based on magnitudes of the selected measured current and voltage signals and/or a phase difference between the selected measured current and voltage signals. As mentioned above, inductance estimator 410 may estimate impedance in any suitable manner, including without limitation using the approaches set forth in U.S. Patent. Appl. No. 17/497,110. Based on the estimated inductance L, a displacement estimator 412 may estimate a displacement D of electromagnetic actuator 304.
- impedance measurement subsystem 308 may experience transient effects when switching between the electromagnetic loads actively being used to perform sensing, as indicated by a change of control signal SENSE_SELECT. Such transient effects may occur due to path delays present in inductance estimator 410, including one or more filters (e.g., low-pass filters) used within inductance estimator 410 to smooth and/or otherwise condition estimation of inductance L.
- filters e.g., low-pass filters
- the sensed inductance value may abruptly change, which may cause filtering artifacts, in turn leading to distorted position estimation.
- Such delay may lead to latency between an event that triggers an actuation and the start of the actuation period.
- electromagnetic transducer 304 is a haptic actuator, it may be critical that latency be minimized to ensure the actuator response is perceived as a mechanical button response to a human interaction.
- reverse inductance estimator 414 may be configured to receive the estimated displacement D from displacement estimator 412 and based thereon, calculate expected state variables (e.g., filter coefficients) associated with the sensing-inactive electromagnetic load (e.g., the electromagnetic load other than the electromagnetic load actively being used to perform sensing).
- expected state variables e.g., filter coefficients
- displacement information estimated from the electromagnetic load actively being used to perform sensing prior to switching between phases may be used to estimate expected values of state variables of the inductance estimator 410 if the inactive load were hypothetically actively sensing.
- inductance estimator 410 may update its state variables based on estimations from reverse inductance estimator 414, to reflect the then-current displacement estimate. Further, to reduce lag between a haptic or other triggering event and start of actuation, state variables of inductance estimator 410 may be updated to reflect the correct displacement estimate.
- the expected state variables may be preset based on an estimate of inductance of the electromagnetic load actively being used to perform sensing following such triggering assuming a displacement D at which electromagnetic actuator 304 is in its resting position.
- Such update of state variables may serve to reduce or eliminate transient effects caused by differences between impedances of electromagnetic coil 301a and electromagnetic coil 301b. Accordingly, such differences in impedances may need to be calibrated with one another, to ensure the estimation performed by reverse inductance estimator 414 remains accurate and precise.
- a calibration procedure may involve driving a high frequency sensing tone on both coils and estimating the high frequency inductance value on both coils simultaneously while also driving a direct current on one of the coils to displace the moving mass of electromagnetic coil 301 into a fixed displacement.
- each electromagnetic coil 301 may then be inferred such that an impedance L 1 (x) of electromagnetic coil 301a may be mapped to an impedance L 2 (x) of electromagnetic coil 301b for a given displacement x of the moving mass away from its resting position.
- L 1 (x) of electromagnetic coil 301a may be mapped to an impedance L 2 (x) of electromagnetic coil 301b for a given displacement x of the moving mass away from its resting position.
- FIGURE 5 illustrates an example graph of high-frequency coil impedance L 1 (x) of electromagnetic coil 301a and high-frequency coil impedance L 2 (x) of electromagnetic coil 301b versus a displacement x of a moving mass of electromagnetic actuator 304, in accordance with embodiments of the present disclosure.
- Electromagnetic coil 301a and electromagnetic coil 301b may not be matched relative to one another or relative to their position vis-a-vis the moving mass of electromagnetic actuator 304.
- Driving a single electromagnetic coil 301 with an actuation signal may not achieve the full range of the moving mass of electromagnetic actuator 304.
- driving an actuation signal on electromagnetic coil 301a may allow for displacement x between limit xMin and a position xE while driving an actuation signal on electromagnetic coil 301b may allow for displacement x between a position xK and limit xMax, as shown in FIGURE 6.
- displacement x may be estimated by driving a high- frequency pilot or test signal into a position-sensing electromagnetic coil 301, measuring a current and a voltage across the coil (or driving a voltage and sensing a current or driving a current and sensing a voltage) and estimating an impedance based on the measurements.
- the functions of high-frequency coil impedance L 1 (x) and high- frequency coil impedance L 2 (x) thus define a mapping between the sensed high- frequency inductance on each electromagnetic coil 301 and displacement x of the moving mass of electromagnetic actuator 304.
- Impedance measurement system 308 may estimate displacement x based on sensing of a single electromagnetic coil 301 or based on sensing of both electromagnetic coil 301a and electromagnetic coil 301b alternately or simultaneously. Using both electromagnetic coil 301a and electromagnetic coil 301b for sensing may allow for selecting the position-sensing electromagnetic coil 301 based on a region in which high-frequency coil impedance L 1 (x) or high-frequency coil impedance L 2 (x) has the greater measurement sensitivity.
- advantages may exist in driving an actuation signal on one electromagnetic coil 301 and position sensing on the other electromagnetic coil 301 in order to simplify or improve detection of the sensed signal. This may be particularly true as the sensing requirements for the position-sense signal and the actuation signal may be very different. For instance, the pilot or test signal driven for position sensing may be small relative to the actuation signal, requiring a high level of amplification.
- function L(x) is not a bijection, mapping impedance to position may require additional states that are updated from a trajectory history of the moving mass of electromagnetic actuator 304.
- sensing regions may be defined differently than that depicted in FIGURE 7.
- one sensing region may cover a larger excursion range of the selected regions and may change based on history of the trajectory.
- some examples of sensing trajectories over one cycle of mass excursion e.g., from limit xMin to limit xMax and back again to limit xMin
- high-frequency coil impedance function L 1 (x) or high- frequency coil impedance function L 2 (x) may not be known with a physical position sensor.
- displacement x may be proportional to the current of a direct-current component of an actuation signal and displacement x may also be proportional to a phase ph of an alternating-current component of the actuation signal.
- high- frequency coil impedance function L 1 (ph) and high-frequency coil impedance function L 2 (ph) may be proxies for high-frequency coil impedance function L 1 (x) and high- frequency coil impedance function L 2 (x), respectively, within an amplitude factor, and may be sufficient for controlling excursion of the moving mass of electromagnetic actuator 304 using a closed-loop system.
- processing subsystem 305 may need to sense the high- frequency inductance of each of electromagnetic coil 301a and electromagnetic coil 301b when they are driven by the same actuation signal on the same coil.
- the actuation signal may be driven independently on each of electromagnetic coil 301a and electromagnetic coil 301b but position sensing may need to occur for both of electromagnetic coil 301a and electromagnetic coil 301b for the same actuation excitation in order to allow for accurate calibration.
- FIGURE 9 illustrates a flow chart of an example method 900 for calibration, in which calibration may be performed with simultaneous driving of actuation signals on both of electromagnetic coil 301a and electromagnetic coil 301b and simultaneous driving of pilot/test signals for sensing on both of electromagnetic coil 301a and electromagnetic coil 301b, in accordance with embodiments of the present disclosure.
- waveform preprocessor 326 may drive low-frequency actuation signals and high-frequency pilot/test signals on both of electromagnetic coil 301a and electromagnetic coil 301b.
- displacement x may oscillate between limits xMin and xMax, and impedance measurement system 308 may wait for the oscillatory behavior to settle.
- impedance measurement system 308 may sense high- frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (X) over at least one oscillation cycle and create a mapping function between high- frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (X) over the range from limit xMin to limit xMax.
- method 900 may end.
- Steps 902 through 906 described above are merely exemplary, and some embodiments may include more or fewer steps than those described above with reference to method 900.
- impedance measurement system 308 may sense high-frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (x) over at least one oscillation cycle and create a mapping function Ml between high- frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (X) valid for the range from limit xMin to position xE.
- waveform preprocessor 326 may drive a low-frequency actuation signal on electromagnetic coil 301b and drive high-frequency pilot/test signals on both of electromagnetic coil 301a and electromagnetic coil 301b.
- displacement x may oscillate between position xK (see FIGURE 6) and limit xMax, and impedance measurement system 308 may wait for the oscillatory behavior to settle.
- impedance measurement system 308 may sense high-frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (x) over at least one oscillation cycle and create a mapping function M2 between high- frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (X) valid for the range from position xK to limit xMax.
- impedance measurement system 308 may merge mapping functions Ml and M2 into a single mapping function M valid for the range from limit xMin to limit xMax. After completion of step 1014, method 1000 may end.
- Steps 1002 through 1014 described above are merely exemplary, and some embodiments may include more or fewer steps than those described above with reference to method 1000.
- FIGURE 11 illustrates a flow chart of an example method 1100 for calibration, in which calibration may be performed with time- multiplexed driving of actuation signals between electromagnetic coil 301a and electromagnetic coil 301b and time-multiplexed driving of pilot/test signals for sensing between electromagnetic coil 301a and electromagnetic coil 301b, in accordance with embodiments of the present disclosure.
- waveform preprocessor 326 may drive a low-frequency actuation signal on electromagnetic coil 301a and drive a high-frequency pilot/test signal on electromagnetic coil 301a.
- displacement x may oscillate between limit xMin and position xE (see FIGURE 6), and impedance measurement system 308 may wait for the oscillatory behavior to settle.
- impedance measurement system 308 may sense high-frequency coil impedance function L 1 (x) over at least one oscillation cycle.
- waveform preprocessor 326 may continue to drive the low- frequency actuation signal on electromagnetic coil 301a, cease driving the high- frequency pilot/test signal on electromagnetic coil 301a, and begin driving a high- frequency pilot/test signal on electromagnetic coil 301b.
- displacement x may oscillate between limit xMin and position xE (see FIGURE 6), and impedance measurement system 308 may wait for the oscillatory behavior to settle.
- impedance measurement system 308 may sense high-frequency coil impedance function L 2 (x) over at least one oscillation cycle.
- impedance measurement system 308 may create a mapping function Ml between high-frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (x) valid for the range from limit xMin to position xE.
- waveform preprocessor 326 may drive a low-frequency actuation signal on electromagnetic coil 301b and drive a high-frequency pilot/test signal on electromagnetic coil 301b.
- displacement x may oscillate between position xK (see FIGURE 6) and limit xMax, and impedance measurement system 308 may wait for the oscillatory behavior to settle.
- impedance measurement system 308 may sense high-frequency coil impedance function L 2 (x) over at least one oscillation cycle.
- waveform preprocessor 326 may continue to drive the low- frequency actuation signal on electromagnetic coil 301b, cease driving the high- frequency pilot/test signal on electromagnetic coil 301b, and begin driving a high- frequency pilot/test signal on electromagnetic coil 301a.
- displacement x may oscillate between position xK (see FIGURE 6) limit xMax, and impedance measurement system 308 may wait for the oscillatory behavior to settle.
- impedance measurement system 308 may sense high-frequency coil impedance function L 1 (x) over at least one oscillation cycle.
- impedance measurement system 308 may create a mapping function M2 between high-frequency coil impedance function L 1 (x) and high-frequency coil impedance function L 2 (x) valid for the range from position xK to limit xMin.
- impedance measurement system 308 may merge mapping functions Ml and M2 into a single mapping function M valid for the range from limit xMin to limit xMax. After completion of step 1130, method 1100 may end.
- Steps 1102 through 1130 described above are merely exemplary, and some embodiments may include more or fewer steps than those described above with reference to method 1100.
- the foregoing contemplates defining a function L(x) between the inductance of a coil and an actuator mass displacement
- such function may establish a mapping between a high-frequency impedance of the coil and the actuator mass displacement.
- the impedance may comprise a resistive portion and a reactive (e.g., inductive) portion.
- references in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Accordingly, modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the scope of the disclosure. For example, the components of the systems and apparatuses may be integrated or separated.
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Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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GB2315494.1A GB2620074A (en) | 2021-05-09 | 2022-03-11 | Position-sensing via impedance estimation of a multi-coil electro-mechanical actuator |
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US202163186169P | 2021-05-09 | 2021-05-09 | |
US63/186,169 | 2021-05-09 | ||
US17/568,248 | 2022-01-04 | ||
US17/568,248 US11948739B2 (en) | 2021-05-09 | 2022-01-04 | Minimizing transient artifact of position estimate in inductively-sensed electromagnetic actuator system with shared inductive sensor |
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Citations (4)
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GB2499026A (en) * | 2012-02-03 | 2013-08-07 | Canon Kk | A loudspeaker driver with sensing coils for sensing the position and velocity of a voice-coil |
US20170256145A1 (en) * | 2014-02-13 | 2017-09-07 | Nxp B.V. | Multi-tone haptic pattern generator |
US20180321748A1 (en) * | 2017-05-08 | 2018-11-08 | Cirrus Logic International Semiconductor Ltd. | Integrated haptic system |
US20190103829A1 (en) * | 2017-09-29 | 2019-04-04 | Apple Inc. | Closed-loop control of linear resonant actuator using back emf and inertial compensation |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2499026A (en) * | 2012-02-03 | 2013-08-07 | Canon Kk | A loudspeaker driver with sensing coils for sensing the position and velocity of a voice-coil |
US20170256145A1 (en) * | 2014-02-13 | 2017-09-07 | Nxp B.V. | Multi-tone haptic pattern generator |
US20180321748A1 (en) * | 2017-05-08 | 2018-11-08 | Cirrus Logic International Semiconductor Ltd. | Integrated haptic system |
US20190103829A1 (en) * | 2017-09-29 | 2019-04-04 | Apple Inc. | Closed-loop control of linear resonant actuator using back emf and inertial compensation |
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