Determining and avoiding over-excursion of the transducer's internal mass

Abstract

A method for determining and mitigating over-excursion of an internal mass of an underdamped electro-mechanical transducer may include converting an electrical playback signal into an estimated displacement signal, determining an estimated over-excursion of the internal mass responsive to the electrical playback signal based on the estimated displacement signal, and limiting an electrical drive signal derived from the electrical playback signal and for driving the electro-mechanical transducer based on the estimated over-excursion to mitigate the over-excursion of the internal mass.

Description

[Technical field]

[0001] The present disclosure generally relates to methods, apparatus, or implementations for haptic devices. In particular, embodiments described herein may disclose systems and methods for detection and prevention of non-linear excursions in haptic actuators. [Background technology]

[0002] Vibro-haptic transducers, e.g., linear resonant actuators (LRAs), are widely used in portable devices such as mobile phones to generate vibration feedback to users. Various forms of vibro-haptic feedback can create different sensations of touch to the user's skin and play an increasing role in human-machine interaction for modern devices.

[0003] An LRA may also be modeled as a mass-spring electromechanical vibration system. When driven with a properly designed or controlled drive signal, the LRA can generate a particular desired type of vibration. For example, a sudden and distinct vibration pattern against a user's finger may be used to create a sensation that mimics a mechanical button click. This distinct vibration may then be used as a virtual switch to replace the mechanical button.

[0004] When a haptic transducer is driven with an electrical signal, the internal mass of the haptic transducer may collide with its external housing, which may have undesirable effects including permanent damage to the transducer, changes to the transducer's characteristics, undesirable audio artifacts (e.g., a loud "clack" sound when the internal mass hits the external housing), and / or distorted haptic effects. Such collisions can be avoided if only "known" content, typically in the form of pre-stored waveforms, is played back to the haptic transducer. Nevertheless, such collisions can occur if playback conditions change or unknown content is played back (e.g., streaming with audio-to-haptic playback). Limiting the playback level for unknown content can reduce or eliminate such collision events, but such a limit may weaken the haptic effect.

[0005] Manufacturers of haptic actuators often specify a maximum signal voltage (e.g., a maximum number of volts, root mean square, at a particular frequency) to minimize or eliminate damage. Excursion limits in terms of displacement or distance can be inferred from such voltage limits. Nevertheless, unknown playback content can make it difficult to comply with manufacturer-inferred excursion limits for under-damped devices such as haptic transducers.

[0006] Methods and systems exist for limiting excursion to speakers, but often do not work well for underdamped devices. In such approaches to limiting speaker excursion, damping is often applied directly to the drive voltage signal sent to the speaker. Yet, because tactile transducers are typically underdamped (i.e., have a high Q factor compared to loudspeakers), applying a limiting voltage signal directly to the drive voltage may not control the mass position such that the excursion is limited to a given threshold.

[0007] Therefore, other approaches to prevent over-excursion for tactile transducers and other underdamped devices may be desirable. Summary of the Invention

[0008] In accordance with the teachings of the present disclosure, disadvantages and problems associated with existing approaches for avoiding over-excursion in tactile transducers may be reduced or eliminated.

[0009] According to an embodiment of the present disclosure, a method for determining and mitigating over-excursion of an internal mass of an underdamped electro-mechanical transducer may include converting an electrical playback signal into an estimated displacement signal, determining an estimated over-excursion of the internal mass responsive to the electrical playback signal based on the estimated displacement signal, and limiting an electrical drive signal derived from the electrical playback signal and for driving the electro-mechanical transducer based on the estimated over-excursion to mitigate the over-excursion of the internal mass.

[0010] In accordance with these and other embodiments of the present disclosure, a method for determining and mitigating over-excursion of an internal mass of an underdamped electromechanical transducer may include determining, for each of a set of known playback waveforms, a transformation for each waveform that minimizes over-excursion of the internal mass based on playback conditions, storing the transformations in memory, and applying the respective transformation associated with the particular known waveform and based on the playback conditions during runtime and playback of the particular known waveform.

[0011] In accordance with these and other embodiments of the present disclosure, a system for determining and mitigating over-excursion of an internal mass of an underdamped electro-mechanical transducer may include an electrical drive-excursion model configured to convert an electrical playback signal into an estimated displacement signal, and an excursion limiter configured to determine an estimated over-excursion of the internal mass responsive to the electrical playback signal based on the estimated displacement signal, and to limit an electrical drive signal derived from the electrical playback signal and for driving the electro-mechanical transducer based on the estimated over-excursion to mitigate the over-excursion of the internal mass.

[0012] In accordance with these and other embodiments of the present disclosure, a system for determining and mitigating over-excursion of an internal mass of an underdamped electromechanical transducer includes a memory configured to store, for each of a set of known playback waveforms, a per-waveform transformation that minimizes over-excursion of the internal mass based on playback conditions, and a controller configured to apply the respective transformation associated with the particular known waveform and based on the playback conditions during runtime and playback of the particular known waveform.

[0013] The technical advantages of the present disclosure may become readily apparent to those skilled in the art from the figures, description, and claims contained herein. The object and advantages of the embodiments will be realized and attained at least by the elements, features, and combinations particularly pointed out in the claims.

[0014] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the scope of the present disclosure as set forth herein.

[0015] A more complete understanding of the present embodiments and their advantages may be obtained by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals indicate like features and in which: [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an illustration of an example of a vibrotactile system in a device, according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram of selected components of an example controller that may be used to implement the controller depicted in FIG. 1, in accordance with an embodiment of the present disclosure. [Diagram 3] FIG. 13 is a diagram of selected components of an example excursion limiter, in accordance with an embodiment of the present disclosure. [Figure 4] FIG. 2 is a diagram of selected components of another example controller that may be used to implement the controller depicted in FIG. 1 in accordance with an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a diagram of selected components of another example controller that may be used to implement the controller depicted in FIG. 1 in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] FIG. 1 illustrates an example of a vibrotactile system in a device 100 according to an embodiment of the present disclosure. As shown in FIG. 1, the device 100 includes a drive signal V applied to an amplifier 102. DRVThe controller 101 may include a controller configured to control a drive signal V DRV The trigger may include, for example, a pressure or force sensor on the screen or a virtual button of the device 100.

[0018] The controller 101 may include any system, device, or apparatus configured to interpret and / or execute program instructions and / or process data, including, without limitation, a microprocessor, a microcontroller, a digital signal processor (DSP), an 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 101 may interpret and / or execute program instructions and / or process data stored in a memory or other computer readable medium (not explicitly shown) communicatively coupled to the controller 101. In some embodiments, as described in more detail below, the controller 101 may generate a drive signal V for driving the vibration actuator 103. DRV may be configured to determine whether a displacement based limit may lead to over-excursion of the internal moving mass of the vibration actuator 103 and to apply a displacement based limit to minimize or eliminate the over-excursion.

[0019] Next, the amplifier 102 outputs the drive signal V DRV Based on the signal, a vibration actuator (e.g., a tactile transducer or other underdamped transducer) 103 may be driven. The amplifier 102 may be any system, device, or apparatus configured to amplify a signal received from the controller 101 and communicate the amplified signal (e.g., to the vibration actuator 103).

[0020] As described above, the controller 101 generates a drive signal V for driving the vibration actuator 103. DRV may lead to over-excursion of the internal moving mass of the vibration actuator 103, and apply a displacement-based limit to minimize or eliminate the over-excursion. To do so, the controller 101 generates a drive signal V DRV A displacement-based transformation can be applied to the raw electrical drive signal to generate

[0021] Figure 2 illustrates selected components of an example controller 101A that may be used to implement the controller 101 depicted in Figure 1, according to an embodiment of the present disclosure. As shown in Figure 2, the controller 101A can include an electric drive-excursion model 202, an excursion limiter 204, and an excursion-electric drive model 206.

[0022] The electric drive-excursion model 202 is a model in which the electric drive-excursion transfer function represents the raw drive signal V DRV When applied to the raw drive signal V DRV is applied to the vibration actuator 103 (or to the amplifier 102 which in turn drives the vibration actuator 103), the estimated displacement D EST For example, the electric drive-excursion model 202 may be based on characteristics derived from testing and / or characterization of the vibration actuator 103 in response to drive voltages at various frequencies and / or amplitudes.

[0023] The excursion limiter 204 limits the displacement D LIMTo generate the estimated displacement D, an excursion threshold (e.g., a safe maximum displacement of the internal mass of the vibration actuator 103) is set EST 3 illustrates selected components of an example excursion limiter 204, in accordance with an embodiment of the present disclosure. As shown in FIG. 3, the excursion limiter 204 can include a look-ahead delay element 302, a gain generator 304, a gain smoother 306, and a gain element 308.

[0024] The look-ahead delay element 302 is a look-ahead displacement D LOOKAHEAD To generate the estimated displacement D, the signal delay is EST Such a delay and look-ahead may be required to detect possible excursion threshold violations and provide signal attenuation before such violations occur.

[0025] The gain generator 304 determines the look-ahead displacement D based on the excursion threshold to maintain the displacement of the internal mass of the vibration actuator 103 below such excursion threshold. LOOKAHEAD Multiplicative attenuating gain G for LIM The gain smoother 306 may comprise any suitable system, device, or apparatus configured to generate a smoothed gain G based on the application of smoothing parameters (e.g., attack, hold, release) and / or filtering. SMOOTH The gain element 308 can generate a limited displacement D LIM To generate the smoothed gain G SMOOTH Look ahead displacement D LOOKAHEAD can be applied to.

[0026] 2, the excursion-electric drive model 206 can comprise an excursion-electric drive transfer function, which can be the inverse transfer function of the electric drive-excursion model 202. Thus, when the excursion-electric drive transfer function of the excursion-electric drive model 206 is applied to a displacement signal representing the excursion of the internal mass of the vibration actuator 103, the result is a drive signal V that, when applied to the vibration actuator 103, maintains the displacement of the internal mass within the excursion threshold. DRV It is.

[0027] Figure 4 illustrates selected components of an example controller 101B that may be used to implement the controller 101 depicted in Figure 1, according to an embodiment of the present disclosure. As shown in Figure 4, the controller 101B may include a look-ahead delay element 402, an electrical drive-excursion model 404, an excursion-gain function 406, and a gain element 408.

[0028] The look-ahead delay element 402 receives the look-ahead drive signal V LOOKAHEAD To generate the raw drive signal V DRV Such a delay and look-ahead may be required to detect excursion threshold violations and provide signal attenuation before such violations occur.

[0029] The electric drive-excursion model 404 is a representation of an electric drive-excursion transfer function that represents the raw drive signal V DRV When applied to the raw drive signal V DRV is applied to the vibration actuator 103 (or to the amplifier 102 which in turn drives the vibration actuator 103), the estimated displacement D ESTFor example, the electric drive-excursion model 202 may be based on characteristics derived from testing and / or characterization of the vibration actuator 103 in response to drive voltages at various frequencies and / or amplitudes. In some embodiments, the electric drive-excursion model 404 may be similar or identical to the electric drive-excursion model 202 depicted in FIG. 2.

[0030] The excursion-gain function 406 adjusts the look-ahead drive signal V based on the excursion threshold to keep the displacement of the internal mass of the vibration actuator 103 below such excursion threshold. LOOKAHEAD Multiplicative attenuation gain G for LIM The gain element 408 may comprise any suitable system, device, or apparatus configured to generate a drive signal V DRV To generate the gain G LIM Read ahead drive signal V LOOKAHEAD can be applied to.

[0031] Figure 5 illustrates selected components of an example controller 101C that may be used to implement the controller 101 depicted in Figure 1, according to an embodiment of the present disclosure. As shown in Figure 5, the controller 101C may include a transform 502 and a lookup table 504 of transforms.

[0032] An offline process may be used in the controller 101C to analyze the known playback content offline and determine a number of electric drive-to-electric drive transformations for each of the known playback waveforms based on different playback conditions. Examples of playback conditions may include temperature, features of the device 100 that are enabled and disabled, and any other suitable conditions. Such transformations may be stored in a lookup table 504, and during runtime of the device 100, the controller 101C detects the playback condition, selects a transformation 502 from the lookup table 504 associated with the known waveform being played back, and generates a drive signal V DRV To generate the raw drive signal V, DRV Such transformations vary in complexity, from simple transformations such as gain, or more complex transformations such as those that manipulate frequency content and / or dynamic range.

[0033] As used herein, when two or more elements are referred to as "coupled" to one another, such terminology indicates that such two or more elements are in electronic or mechanical communication, where applicable, whether indirectly connected or directly connected, with or without intervening elements.

[0034] The present disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the illustrative embodiments herein that would be understood by a person skilled in the art. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the illustrative embodiments herein that would be understood by a person skilled in the art. Moreover, references in the appended claims to an apparatus or system, or an apparatus or system component, adapted for, arranged for, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompass the apparatus, system, or component, or the particular function, whether or not it 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, apparatus, and methods described herein without departing from the scope of the present disclosure. For example, components of the systems and devices may be integrated or separated. Moreover, 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, 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.

[0035] Although example embodiments are illustrated in the figures and described below, the principles of the present disclosure may be implemented using any number of techniques, whether currently known or not, and the present disclosure should in no way be limited to the example implementations and techniques illustrated in the figures and described above.

[0036] Unless specifically noted otherwise, objects depicted in the drawings are not necessarily drawn to scale.

[0037] All examples and conditional language recited herein are intended to aid the reader in understanding the present disclosure and concepts contributed by the inventor to further the present technology for teaching purposes, and are not to be construed as being limited to such specifically recited examples and conditions. Although embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present disclosure.

[0038] While certain advantages have been enumerated above, various embodiments may include some, all, or none of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after reviewing the foregoing figures and description.

[0039] In order to assist patent offices, and any readers of any patents issued on this application, in interpreting the claims appended hereto, applicant wishes to point out that none of the appended claims or claim elements are intended to invoke 35 U.S.C. 112(f) unless the words "means for" or "step for" are expressly used in a particular claim.

Claims

1. 1. A method for determining and mitigating over-excursion of an internal mass of an underdamped electromechanical transducer, comprising: converting the electrical playback signal into an estimated displacement signal; determining an estimated over-excursion of the inner mass in response to the electrical playback signal based on the estimated displacement signal; limiting an electrical drive signal derived from the electrical playback signal and for driving the electro-mechanical transducer based on the estimated over-excursion to mitigate over-excursion of the internal mass; A method comprising:

2. The step of limiting the electrical drive signal further comprises: applying an excursion threshold to the displacement signal to generate a limited displacement signal; converting said limited displacement signal into said electrical drive signal; The method of claim 1 , comprising:

3. The step of limiting the electrical drive signal further comprises: delaying the electrical playback signal to generate a delayed electrical playback signal; generating a signal gain based on the estimated over-excursion; applying the gain to the delayed electrical playback signal to generate the electrical drive signal; The method of claim 1 , comprising:

4. 1. A method for determining and mitigating over-excursion of an internal mass of an underdamped electromechanical transducer, comprising: determining, for each of a set of known playback waveforms, a transformation for each waveform that minimizes over-excursion of said internal mass based on playback conditions; storing said transformation in a memory; applying respective transformations during runtime and playback of the particular known waveform, the transformations being associated with the particular known waveform and based on playback conditions; A method comprising:

5. 1. A system for determining and mitigating over-excursion of an internal mass of an underdamped electromechanical transducer, comprising: an electrical actuation-excursion model configured to convert the electrical playback signal into an estimated displacement signal; An excursion limiter comprising: determining an estimated over-excursion of the inner mass in response to the electrical playback signal based on the estimated displacement signal; and limiting an electrical drive signal derived from the electrical playback signal and for driving the electro-mechanical transducer based on the estimated over-excursion to mitigate over-excursion of the internal mass. an excursion limiter configured to A system comprising:

6. limiting the electrical drive signal applying an excursion threshold to the displacement signal to generate a limited displacement signal; and converting said limited displacement signal into said electrical drive signal; The system of claim 5 , comprising:

7. limiting the electrical drive signal delaying the electrical playback signal to generate a delayed electrical playback signal; generating a signal gain based on the estimated over-excursion; and applying the gain to the delayed electrical playback signal to generate the electrical drive signal. The system of claim 5 , comprising:

8. 1. A system for determining and mitigating over-excursion of an internal mass of an underdamped electromechanical transducer, comprising: a memory configured to store, for each of a set of known playback waveforms, a transformation for each waveform that minimizes over-excursion of the internal mass based on playback conditions; a controller configured to apply respective transformations during runtime and playback of a particular known waveform, the transformations being associated with the particular known waveform and based on playback conditions; A system comprising:

Images