HAPTIC DRIVER WITH ATTENUATION
In each of the various embodiments, a haptic driver is configured to attenuate a drive signal of an actuator. In particular, the haptic drivers described herein are configured to identify the resonance frequency of the actuator and to attenuate the haptic drive signal within a range of frequencies, the range being based on the identified resonance frequency. As a result, the strength of haptic effects produced by the actuator may be more uniform along a wider frequency range.
This application is a continuation of U.S. patent application Ser. No. 15/240,682, filed on Aug. 18, 2016, which claims the benefits of U.S. Provisional Patent Application No. 62/208,430, filed on Aug. 21, 2015, both of which have been incorporated herein by reference in their entirety.
FIELD OF INVENTIONThe embodiments of the present invention are generally directed to electronic devices, and more particularly, to electronic devices that produce haptic effects.
BACKGROUNDElectronic device manufacturers strive to produce a rich interface for users. Conventional devices use visual and auditory cues to provide feedback to a user. In some interface devices, kinesthetic feedback (such as active and resistive force feedback) and/or tactile feedback (such as vibration, texture, and heat) is also provided to the user, more generally known collectively as “haptic feedback” or “haptic effects”. Haptic feedback can provide cues that enhance and simplify the user interface. Specifically, vibration effects, or vibrotactile haptic effects, may be useful in providing cues to users of electronic devices to alert the user to specific events, or provide realistic feedback to create greater sensory immersion within a simulated or virtual environment.
With the development of recent high resolution mobile devices such as smart phones and tablets, users are now able to view high definition audio and video on a handheld device that traditionally could only be seen in movie theaters, television or home theater systems. With haptically enabled mobile devices, experience has shown that content viewing is sufficiently enhanced, and viewers like it, if there is a haptic content component in addition to the audio and video content components. However, in order to be compatible with the high definition audio/video, corresponding high definition or high bandwidth haptic effects should also be generated.
SUMMARY OF THE INVENTIONEmbodiments of the present invention are directed toward electronic devices configured to produce haptic effects that substantially improve upon the related art.
Features and advantages of the embodiments are set forth in the description which follows, or will be apparent from the description, or may be learned by practice of the invention.
In one example, systems and methods include instructions for driving a haptic device including receiving a haptic drive signal configured to drive the haptic output device, identifying a resonance frequency range of the haptic output device, and attenuating the haptic drive signal corresponding to the identified resonant frequency.
Further embodiments, details, advantages, and modifications will become apparent from the following detailed description of the preferred embodiments, which is to be taken in conjunction with the accompanying drawings.
Reference will now be made in detail to embodiments, examples of which are illustrated by the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. Wherever possible, like reference numbers will be used for like elements.
The example embodiments are generally directed toward an improved haptic driver, especially an improved high definition (“HD”) haptic driver. In each of the various embodiments, the haptic driver is configured to attenuate a drive signal of an actuator. In particular, the haptic drivers described herein are configured to determine or otherwise identify the resonance frequency of the actuator and to attenuate the haptic drive signal within a range of frequencies. The range of frequencies corresponds to the resonance frequency. As a result, the strength of haptic effects produced by the actuator may be more uniform along a wider frequency range.
Internal to system 10 is a haptic feedback system that generates haptic effects on system 10 and includes a processor or controller 12. Coupled to processor 12 is a memory 20, and a haptic drive circuit 16 which is coupled to an actuator 18. Processor 12 may be any type of general purpose processor, or could be a processor specifically designed to provide haptic effects, such as an application-specific integrated circuit (“ASIC”). Processor 12 may be the same processor that operates the entire system 10, or may be a separate processor. Processor 12 can decide what haptic effects are to be played and the order in which the effects are played based on high level parameters. In general, the high level parameters that define a particular haptic effect include magnitude, frequency and duration. Low level parameters such as streaming motor commands could also be used to determine a particular haptic effect. A haptic effect may be considered “dynamic” if it includes some variation of these parameters when the haptic effect is generated or a variation of these parameters based on a user's interaction. The haptic feedback system in one embodiment generates vibrations 30, 31 or other types of haptic effects on system 10.
Processor 12 outputs the control signals to haptic drive circuit 16, which includes electronic components and circuitry used to supply actuator 18 with the required electrical current and voltage (i.e., “motor signals”) to cause the desired haptic effects. System 10 may include more than one actuator 18, and each actuator may include a separate drive circuit 16, all coupled to a common processor 12.
Haptic drive circuit 16 is configured to attenuate the haptic drive signal at and around the resonance frequency (e.g. +/−20 Hz, 30 Hz, 40 Hz, etc.) of actuator 16. By attenuating the range of frequencies near the resonance frequency, the haptic strength becomes more uniform over a wider frequency band. In certain embodiments, haptic drive circuit 16 may comprise a variety of signal processing stages, each stage defining a subset of the signal processing stages applied to attenuate the haptic drive signal.
Non-transitory memory 20 may include a variety of computer-readable media that may be accessed by processor 12. In the various embodiments, memory 20 and other memory devices described herein may include a volatile and nonvolatile medium, removable and non-removable medium. For example, memory 20 may include any combination of random access memory (“RAM”), dynamic RAM (“DRAM”), static RAM (“SRAM”), read only memory (“ROM”), flash memory, cache memory, and/or any other type of non-transitory computer-readable medium. Memory 20 stores instructions executed by processor 12. Among the instructions, memory 20 includes audio haptic simulation module 22, which are instructions that, when executed by processor 12, generates high bandwidth haptic effects using speaker 28 and actuator 18, as disclosed in more detail below. Memory 20 may also be located internal to processor 12, or any combination of internal and external memory.
System 10 may be any type of handheld/mobile device, such as a cellular telephone, personal digital assistant (“PDA”), smartphone, computer tablet, gaming console, remote control, or any other type of device that includes a haptic effect system that includes one or more actuators. System 10 may be a wearable device such as wrist bands, headbands, eyeglasses, rings, leg bands, arrays integrated into clothing, etc., or any other type of device that a user may wear on a body or can be held by a user and that is haptically enabled, including furniture or a vehicle steering wheel. Further, some of the elements or functionality of system 10 may be remotely located or may be implemented by another device that is in communication with the remaining elements of system 10.
Actuator 18 may be any type of actuator or haptic output device that can generate a haptic effect. In general, an actuator is an example of a haptic output device, where a haptic output device is a device configured to output haptic effects, such as vibrotactile haptic effects, electrostatic friction haptic effects, temperature variation, and/or deformation haptic effects, in response to a drive signal. Although the term actuator may be used throughout the detailed description, the embodiments of the invention may be readily applied to a variety of haptic output devices. Actuator 18 may be, for example, an electric motor, an electro-magnetic actuator, a voice coil, a shape memory alloy, an electro-active polymer, a solenoid, an eccentric rotating mass motor (“ERM”), a harmonic ERM motor (“HERM”), a linear resonance actuator (“LRA”), a solenoid resonance actuator (“SRA”), a piezoelectric actuator, a macro fiber composite (“MFC”) actuator, a high bandwidth actuator, an electroactive polymer (“EAP”) actuator, an electrostatic friction display, an ultrasonic vibration generator, or the like. In some instances, the actuator itself may include an haptic drive circuit.
In addition to, or in place of, actuator 18, system 10 may include other types of haptic output devices (not shown) that may be non-mechanical or non-vibratory devices such as devices that use electrostatic friction (“ESF”), ultrasonic surface friction (“USF”), devices that induce acoustic radiation pressure with an ultrasonic haptic transducer, devices that use a haptic substrate and a flexible or deformable surface or shape changing devices and that may be attached to a user's body, devices that provide projected haptic output such as a puff of air using an air jet, etc.
In general, an actuator may be characterized as a standard definition (“SD”) actuator that generates vibratory haptic effects at a single frequency. Examples of an SD actuator include ERM and LRA. By contrast to an SD actuator, an HD actuator or high fidelity actuator such as a piezoelectric actuator or an EAP actuator is capable of generating high bandwidth/definition haptic effects at multiple frequencies. HD actuators are characterized by their ability to produce wide bandwidth tactile effects with variable amplitude and with a fast response to transient drive signals.
Actuators, especially HD actuators, are very responsive at their resonance frequencies. For example, HD actuators provide significantly higher haptic strength at their resonance frequencies. Such actuators, when driven at the rated voltage, produce a high amount of force. As a result, the actuators may hit internal portions of the housing of their host device. For example, the actuator may hit end stops located within the housing, and a loud and annoying noise may be produced as a result. For some actuator types, which are configured to carry a load or mass (e.g., a piezoelectric actuator), even larger forces may be produced resulting in even louder noises.
One method to solve this problem is to drive the actuator below its rated voltage. The significant drawback of this approach is a diminished haptic experience because the actuator produces less acceleration at all frequencies. In addition, there is a high degree of variance between similarly rated actuators. As a result, the similarly rated actuators often produce inconsistent haptic responses. The variance is especially large between different actuator manufacturers, but is still significant among actuators produced by a single manufacturer. Known solutions attempt to simulate and modify haptic drive signal strength externally, such as applying a software algorithm before sending the data. However, such techniques are overly complex and do not produce consistent haptic responses. By contrast, embodiments of the invention are directed to an internal solution at the integrated circuit level of the haptic driver (e.g., haptic driver circuit 16).
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Although the use of a notch filter is described in connection with the examples of
At the outset, functionality 300 may receive one or more haptic drive signals configured to drive the actuator, at 310. Next, at 320, functionality 300 determines or identifies the resonance frequency or the resonance frequency range of the actuator. The resonance frequencies may be determined using a variety of techniques. For example, the resonance frequencies may be automatically determined by monitoring the operation of the actuator. Alternatively, the resonance frequencies may be supplied by the actuator or may be determined by using a look-up table. In yet another example, the resonance frequencies may be determined using one or more back electromotive force (“back-EMF”) algorithms. Lastly, the received haptic drive signal is attenuated at frequencies corresponding to the detected resonant frequencies, at 330. One or more filters may be applied to attenuate the haptic drive signal at resonant frequencies. In some instances, the haptic drive signal voltage may also be boosted.
Embodiments of the invention are directed to haptic drivers, especially HD haptic drivers (e.g., haptic drive circuit 16 of
As shown in
In the next stage, digital haptic data signal 410 is supplied to digital to analog converter (“DAC”) 450. Supplied with haptic control data 415 by configuration controller 430, DAC 450 converts the digital haptic data signal to analog haptic data signal 410′. Here, haptic control data 415 may be used to further adjust the drive voltage and attenuation parameters of digital haptic data signal 410 during the digital to analog conversion stage.
Subsequently, at power stage 460, analog haptic data signal 410′ is received and its voltage level may be varied depending on the input parameters of subsequent stages. For example, power stage 460 may be configured to adjust the voltage level of analog haptic data signal 410′ using one or more output filters.
As shown in
In the next stage, analog haptic data signal 510′ is supplied to signal conditioner 550. Using haptic control data 515 that is supplied by configuration controller 530, signal conditioner 550 may alter analog haptic data signal 510′ using one or more analog filtering algorithms that utilize haptic control data 515. For example, a variety of analog filters, such as an RC filter, may be used. More complex filters may be implemented in semiconductor device depending on the design. In some instances, signal conditioner 550 may further be applied to enhance the characteristics of silicon used to fabricate the actuator located at a subsequent stage. In the various embodiments, haptic control data 515 may be used to modify the drive voltage and attenuation parameters of analog haptic data signal 510′.
Subsequently, at power stage 560, analog haptic data signal 510′ is received and its voltage level may be varied depending on the input parameters of subsequent stages. For example, power stage 560 may be configured to adjust the voltage level of analog haptic data signal 510′ using one or more output filters.
As shown in
In this example embodiment, haptic control data 615 is supplied to resonance detector 645. Using the resonance detector 645, haptic driver 600 may readily determine the resonance frequency of a down stage actuator. For example, resonance detector 645 may be configured to scan and/or otherwise automatically determine the resonance frequency of the actuator. In some instances, the resonance frequency band and corresponding attenuation may be adjusted. In another example, resonance detector 645 may be configured to detect changes in resonance frequency using a sensing mechanism (e.g., located at the haptic device) to measure force or applied pressure. In yet another example, the actuator itself may supply its resonance frequency. In yet another example, back-EMF may be used to determine the resonance frequency of the actuator. Use of back-EMF to determine one or more characteristics of the actuator is described, for example, in U.S. Pat. No. 7,843,277, which is hereby incorporated by reference. Haptic control data 615 may be supplied to resonance detector 645. Resonance detector 645 may be an auto resonance detector adapted to use configuration parameters supplied by haptic control data 615 and configuration controller 630. To reduce time of resonance detection for an individual actuator, configuration parameters (e.g., frequency of resonance from data sheet) may be provided as a starting point. Additional configuration parameters, such as back-EMF gain may be provided to prevent false detection.
In the next stage, analog haptic data signal 610′, resonance detection signal 646, and haptic control data 615 are supplied to signal conditioner 650. Using these inputs, signal conditioner 650 may alter analog haptic data signal 610′. In the various embodiments, haptic control data 615 may include resonance frequency data, resonance bandwidth data, and attenuation data that may be used to modify the drive voltage and attenuation parameters of digital haptic data signal haptic data signal 610′.
Subsequently, at power stage 660, analog haptic data signal 610′ is received and its voltage level may be varied depending on the input parameters of subsequent stages. For example, power stage 660 may be configured to adjust the voltage level of analog haptic data signal 610′ using one or more output filters.
As shown in
In the next stage, analog haptic data signal 710′ is supplied to signal conditioner 750. In this embodiment, signal conditioner 750 uses a lookup table (not shown). The lookup table may be supplied by the user or be preprogrammed. For example, the look-up table may store the frequency response characteristics for multiple actuators made by a variety of manufacturers. Using the lookup table and haptic control data 715 that is supplied by configuration controller 730, signal conditioner 750 may alter analog haptic data signal 710′. In the various embodiments, haptic control data 715 may be used to modify the drive voltage and attenuation parameters of analog haptic data signal 710′.
Subsequently, at power stage 760, analog haptic data signal 710′ is received and its voltage level may be varied depending on the input parameters of subsequent stages. For example, power stage 760 may be configured to adjust the voltage level of analog haptic data signal 710′ using one or more output filters.
As shown in
Subsequently, the digital haptic data signal 810 is supplied to DAC 840. Supplied with haptic control data 815 by configuration controller 830, DAC 850 converts the digital haptic data signal 810 to analog haptic data signal 810′. Haptic control data 815 may be used to modify the drive voltage and attenuation parameters of digital haptic data signal 810 during the digital to analog conversion stage.
In the next stage, analog haptic data signal 810′ is supplied to signal conditioner 860. Using analog haptic data signal 810′ and haptic control data 815, signal conditioner 860 may alter analog haptic data signal 810′. As discussed above, signal conditioner may apply signal conditioning based on a programmed parameter, a resonance detection mechanism, a look-up table, and the like.
Lastly, at power stage 870, analog haptic data signal 810′ is received and its voltage level may be varied depending on the input parameters of subsequent stages. For example, power stage 870 may be configured to adjust the voltage level of analog haptic data signal 810′ using one or more output filters.
As discussed above, the embodiments of the invention provide significant improvement and uniformity in haptic experience over a wider frequency band. Moreover, the overall frequency response of the haptic actuators is improved. The HD haptic drivers described herein provide uniform control of haptic actuators made by different manufacturers and help to render consistent haptic experience over wider frequency ranges by improving the haptic response of the actuators to make it usable for wider frequency band and provide uniform/consistent experience.
Several embodiments have been specifically illustrated and/or described. However, it will be appreciated that modifications and variations of the disclosed embodiments are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention. The embodiments described herein are only some of the many possible implementations. It should be noted that some of the blocks can be combined to optimize silicon/IC usage. Furthermore, the embodiments may be readily applied to various actuator types and other haptic output devices.
Claims
1. (canceled)
2. A haptic driver comprising:
- a memory configured to receive a digital haptic drive signal;
- a configuration controller configured to receive haptic control data;
- a signal modifier configured to modify the digital haptic drive signal according to the haptic control data; and
- a digital-to-analog converter configured to covert the digital haptic drive signal to an analog haptic drive signal.
3. The haptic driver according to claim 2, further comprising:
- a power stage configured to vary a voltage level of the analog haptic drive signal according to the haptic control data.
4. The haptic driver according to claim 2, wherein the signal modifier attenuates the digital haptic drive signal at frequencies corresponding to a resonance frequency range of a haptic output device.
5. The haptic driver according to claim 4, wherein the haptic output device is a high definition haptic output device that is configured to produce wide bandwidth haptic effects.
6. The haptic driver according to claim 2, wherein the signal modifier attenuates the digital haptic drive signal using a notch filter.
7. The haptic driver according to claim 2, wherein the haptic control data includes at least one of resonance frequency data, resonance bandwidth data, and attenuation data.
8. A haptic driver comprising:
- a memory configured to receive a digital haptic drive signal;
- a configuration controller configured to receive haptic control data;
- a digital-to-analog converter configured to covert the digital haptic drive signal to an analog haptic drive signal; and
- a signal conditioner configured to modify the analog haptic drive signal according to the haptic control data.
9. The haptic driver according to claim 8, further comprising:
- a power stage configured to vary a voltage level of the analog haptic drive signal according to the haptic control data.
10. The haptic driver according to claim 8, wherein the signal conditioner attenuates the analog haptic drive signal at frequencies corresponding to a resonance frequency range of a haptic output device.
11. The haptic driver according to claim 10, wherein the haptic output device is a high definition haptic output device that is configured to produce wide bandwidth haptic effects.
12. The haptic driver according to claim 8, wherein the signal conditioner attenuates the analog haptic drive signal using a notch filter.
13. The haptic driver according to claim 8, wherein the haptic control data includes at least one of resonance frequency data, resonance bandwidth data, and attenuation data.
14. The haptic driver according to claim 8, further comprising:
- a resonance detector configured to detect a resonance frequency range for a haptic output device.
15. The haptic driver according to claim 14,
- wherein the resonance frequency range is automatically determined by monitoring operation of the haptic output device;
- wherein the resonance frequency range is supplied by the haptic output device or is determined by using a look-up table; or
- wherein the resonance frequency range is automatically determined using back-EMF.
16. A method for operating a haptic driver comprising:
- receiving, at a memory, a digital haptic drive signal;
- receiving, at a configuration controller, haptic control data;
- modifying, at a signal modifier, the digital haptic drive signal according to the haptic control data; and
- converting, at a digital-to-analog, the digital haptic drive signal to an analog haptic drive signal.
17. The method according to claim 16, further comprising:
- varying, at a power stage, a voltage level of the analog haptic drive signal according to the haptic control data.
18. The method according to claim 16, wherein the signal modifier attenuates the digital haptic drive signal at frequencies corresponding to a resonance frequency range of a haptic output device.
19. The method according to claim 18, wherein the haptic output device is a high definition haptic output device that is configured to produce wide bandwidth haptic effects.
20. The method according to claim 16, wherein the signal modifier attenuates the digital haptic drive signal using a notch filter.
21. The method according to claim 16, wherein the haptic control data includes at least one of resonance frequency data, resonance bandwidth data, and attenuation data.
Type: Application
Filed: Sep 12, 2018
Publication Date: Mar 14, 2019
Inventor: Kaniyalal SHAH (Fremont, CA)
Application Number: 16/129,064