Dampening Mechanical Modes of a Haptic Actuator Using a Delay

• US 20170285747A1
• Filed: 11/30/2016
• Published: 10/05/2017
• Est. Priority Date: 03/31/2016
• Status: Active Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chen, Denis G.
• Granted Patent: US 10,268,272 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G08B 6/00 Tactile signalling systems, e.g. personal calling systems

Abstract

Described herein is a method for determining a higher order resonance mode frequency of a haptic actuator for an electronic device. The higher order resonance mode frequency may correspond to a frequency in which a mass of the haptic actuator exhibits undesired movement. The movement may cause the mass to collide or otherwise impact an enclosure of the haptic actuator. Once the higher order resonance mode frequency is determined, a delay or a polarity inversion may be added to one or more of a series of input waveforms to suppress or brake the undesired movement.

Claims

1. An electronic device, comprising:

a processing unit;

a memory; and

a haptic actuator;

wherein

the memory is operative to store instructions for generating a plurality of input waveforms to drive the haptic actuator; and

the processing unit is operative to determine a delay to be provided between alternating input waveforms provided to the haptic actuator, the delay operative to suppress a higher order resonance mode response of an actuator mass of the haptic actuator.

2. The electronic device of claim 1, wherein the delay is based, at least in part, on a higher order resonance mode frequency associated with the haptic actuator.

3. The electronic device of claim 1, wherein the higher order resonance mode response results in the actuator mass impacting an internal portion of the haptic actuator resulting in an audible sound.

4. The electronic device of claim 1, further comprising an interpreter operative to alter the delay based, at least in part, on the plurality of input waveforms that are provided to the haptic actuator.

5. The electronic device of claim 1, wherein the delay causes an input waveform of the plurality of input waveforms to have a frequency component that is phase shifted by approximately 180 degrees with respect to a higher order resonance mode frequency associated with the haptic actuator.

6. The electronic device of claim 1, wherein the delay is in a range of approximately 1 ms to approximately 4 ms.

7. A method for determining a higher order resonance mode frequency of an actuator for an electronic device, comprising:

providing a first series of input waveforms to the actuator to cause the actuator to move, the first series of input waveforms having a first period;

providing a sweep of multiple subsequent series of input waveforms to the actuator, each subsequent series of input waveforms having a respective period that belongs to a set of monotonically incremented values with respect to the first period;

identifying one or more periods that result in an actuator mass of the actuator impacting an internal portion of the actuator; and

estimating the higher order resonance mode frequency of the actuator using the identified one or more periods.

8. The method of claim 7, wherein estimating the higher order resonance mode frequency includes computing a mean of the identified one or more periods.

9. The method of claim 7, wherein estimating the higher order resonance mode frequency of the actuator further comprises:

identifying a harmonic frequency associated with consecutive multiples of the identified one or more periods that result in the actuator mass of the actuator impacting the internal portion of the actuator.

10. The method of claim 9, wherein the harmonic frequency is an integer multiple of a frequency associated with one of the one or more identified periods.

11. The method of claim 7, wherein the first period is approximately 40 ms to approximately 80 ms.

12. The method of claim 7, wherein the respective periods are incremented by approximately 1 ms to approximately 5 ms.

13. The method of claim 7, further comprising providing a second sweep of multiple subsequent series of input waveforms to the actuator when the first sweep did not result in the actuator mass of the actuator impacting the internal portion of the actuator.

14. The method of claim 7, further comprising determining a delay that is added to at least one input waveform to offset a response of the actuator at the higher order resonance mode frequency, the delay being based, at least in part, on the estimated higher order resonance mode frequency.

15. The method of claim 7, further comprising grouping at least two input waveforms in the series of input waveforms together.

16. The method of claim 15, further comprising providing a delay between the grouping of the at least two input waveforms.

17. The method of claim 7, wherein a polarity of every second input waveform is reversed based on a waveform pitch and the estimated higher order resonance mode frequency.

18. A method for determining a delay that is provided between input waveforms applied as input to a haptic actuator, comprising:

determining a higher order resonance mode frequency of the haptic actuator;

determining a period of a higher order resonance mode; and

determining the delay using the higher order resonance mode frequency and the period of the higher order resonance mode.

19. The method of claim 18, wherein:

determining the higher order resonance mode frequency of the haptic actuator comprises providing a series of input waveforms to the haptic actuator; and

defining multiple periods between multiple pairs of subsequent input waveforms.

20. The method of claim 19, further comprising identifying one or more periods that result in an actuator mass of the haptic actuator impacting an internal surface of the haptic actuator.

21. The method of claim 18, further comprising automatically inserting the delay to one or more input waveforms of a series of input waveforms provided to the haptic actuator.