Dampening Mechanical Modes of a Haptic Actuator Using a Delay

• US 20190250713A1
• Filed: 04/22/2019
• Published: 08/15/2019
• Est. Priority Date: 03/31/2016
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chen, Denis G.
• Granted Patent: US 10,809,805 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:

an enclosure;

a haptic actuator mounted within the enclosure and comprising a movable mass; and

a processor configured to apply a series of input waveforms to the haptic actuator, wherein;

the applied series of input waveforms moves the movable mass to provide a haptic output;

the processor applies a first input waveform and a second input waveform in the series of input waveforms with a delay between the first input waveform and the second input waveform; and

the processor configures the delay to reduce unwanted movement of the movable mass.

2. The electronic device of claim 1, wherein the processor configures the delay to prevent the movable mass from contacting the enclosure.

3. The electronic device of claim 2, wherein the delay prevents the movable mass from contacting the enclosure by suppressing a motion of the movable mass associated with a higher order resonance mode, the higher order resonance mode distinct from a designed resonance mode of the movable mass.

4. The electronic device of claim 3, wherein the motion of the movable mass according to the designed resonance mode is along an axis, and the motion of the movable mass associated with a higher order resonance mode is a rotational motion about the axis.

5. The electronic device of claim 3, wherein the delay causes a frequency component of the second input waveform at the frequency of the higher order resonance mode to suppress a frequency component of the first input waveform at the frequency of the higher order resonance mode.

6. The electronic device of claim 1, wherein each input waveform in the series of input waveforms occurs during a respective period, each period having the same duration and occurring sequentially.

7. The electronic device of claim 6, wherein the delay occurs at a beginning of the respective period of the second input waveform.

8. The electronic device of claim 7, wherein the delay is applied between every other input waveform in the series of input waveforms.

9. The electronic device of claim 1, wherein the first and second waveforms are selected by the processor from a predefined library stored in a memory of the electronic device.

10. An electronic device, comprising:

a housing;

a haptic actuator mounted within the housing and comprising a mass; and

a processor configured to apply a series of input waveforms to the haptic actuator, wherein;

the applied series of input waveforms moves the mass along an axis to provide a haptic output;

the processor applies a first input waveform and a second input waveform in the series of input waveforms with a delay between the first input waveform and the second input waveform; and

the processor configures the delay to reduce rotational movement of the mass about the axis.

11. The electronic device of claim 10, wherein:

the applied series of input waveforms moves the mass according to a designed resonance mode, and

the processor is configured to determine the series of input waveforms by;

receiving at least one frequency corresponding to at least one higher order resonance mode of the haptic actuator; and

determining at least one delay to be inserted within the series of input waveforms so that the series of input waveforms has a frequency response having at least one frequency null at the at least one frequency.

12. The electronic device of claim 11, wherein:

the haptic actuator further comprises a spring connected between the housing and the mass;

the spring induces the rotational movement of the mass about the axis at the at least one higher order resonance mode; and

the at least one delay suppresses the rotational movement of the mass about the axis at the at least one higher order resonance mode.

13. The electronic device of claim 12, wherein the at least one delay prevents the mass from contacting the housing of the electronic device.

14. The electronic device of claim 11, wherein:

the processor is configured to determine the series of input waveforms by;

receiving multiple frequencies corresponding to multiple higher order resonance modes of the haptic actuator; and

determining multiple delays to be inserted within the series of input waveforms so that the series of input waveforms has a frequency response having frequency nulls at the multiple frequencies corresponding to the multiple higher order resonance modes of the haptic actuator.

15. The electronic device of claim 14, wherein the multiple delays are determined according to a binary hierarchy.

16. A method of operating a haptic actuator within an electronic device, the method comprising:

determining a first delay based, at least in part, on a first higher order resonance mode of the haptic actuator;

determining a second delay based, at least in part, on a second higher order resonance mode of the haptic actuator; and

sequentially applying a first, second, third, and fourth input waveform to the haptic actuator during respective first, second, third, and fourth sequential time periods to cause a mass of the haptic actuator to move according to a designed resonance mode and provide a haptic output,

wherein;

the designed resonance mode is distinct from the first and second higher order resonance modes;

the first delay is inserted at a beginning of the second time period before the second input waveform;

the second delay is inserted at a beginning of the third time period before the third input waveform;

the first delay and the second delay are inserted at a beginning of the fourth time period before the fourth input waveform; and

the first delay and second delay suppress motions of the mass according to the first higher order resonance mode and the second higher order resonance mode.

17. The method of claim 16, wherein the first, second, third, and fourth sequential time periods have the same duration.

18. The method of claim 16, wherein the first and second delays are determined so that respective frequency components of the first, second, third, and fourth input waveforms combine to produce a first frequency null at a first frequency associated with the first higher order resonance mode and combine to produce a second frequency null at a second frequency associated with the second higher order resonance mode.

19. The method of claim 18, further comprising:

determining a change in at least one of the first frequency associated with the first higher order resonance mode and the second frequency associated with the second higher order resonance mode;

determining an updated first delay and an updated second delay using the determined change; and

repeating the sequential application of the first, second, third, and fourth input waveforms to the haptic actuator using the updated first delay instead of the first delay and using the updated second delay instead of the second delay.

20. The method of claim 16, further comprising selecting the first, second, third, and fourth input waveforms based on the haptic output.