Haptic actuator including field member multi-dimensional position determined based upon coil back electromotive force and motor constant values and related methods

Patent metadata

Field	Value
Publication number	US-10345907-B2
Application number	US-201715814626-A
Country	US
Kind code	B2
Filing date	Nov 16, 2017
Priority date	Sep 1, 2017
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A haptic actuator may include a housing, coils carried within the housing, and a field member moveable within the housing between the coils and including at least one permanent magnet. A controller may be coupled to the coils and configured to sense a respective back electromotive force (EMF) value of each of the coils and determine a position of the field member in dimensions based upon the back EMF values and motor constant values.

First claim

That which is claimed is:

1. A haptic actuator comprising:
a housing;
a plurality of coils carried within the housing;
a field member moveable within the housing between the plurality of coils and comprising at least one permanent magnet; and
a controller coupled to the plurality of coils and configured to
sense a respective back electromotive force (EMF) value of each of the plurality of coils, and
determine a position of the field member in a plurality of dimensions based upon the back EMF values and motor constant values.

2. The haptic actuator of claim 1 wherein the housing has a top and bottom; wherein the plurality of coils comprises a plurality of coil pairs, each coil pair comprising top and bottom opposing coils, the motor constant values corresponding to respective motor constant values associated with each coil pair; and wherein the controller is configured to sense the respective back EMF value of each coil pair.

3. The haptic actuator of claim 1 wherein the housing has a top and bottom; wherein the plurality of coils comprises a plurality of coil pairs, each coil pair comprising top and bottom opposing coils; and wherein the controller is configured to sense the respective back EMF value of at least one coil pair while driving at least one other coil pair.

4. The haptic actuator of claim 1 wherein the housing has a top and bottom; wherein the plurality of coils comprises a plurality of coil pairs, each coil pair comprising left and right opposing coils, the motor constant values corresponding to respective motor constant values associated with each coil pair; and wherein the controller is configured to sense the respective back EMF value of each coil pair.

5. The haptic actuator of claim 1 wherein the housing has a top and bottom; wherein the plurality of coils comprises at least one coil pair; wherein the field member has opposing first and second sides; wherein the haptic actuator further comprises a respective at least one flexure bearing mounting each of the first and second sides of the field member to be reciprocally movable within the housing responsive to the at least one coil pair, the respective at least one flexure bearing and the field member having a resonant frequency of torsion associated therewith; and wherein the controller is configured to drive the haptic actuator to the resonant frequency of torsion.

6. The haptic actuator of claim 1 wherein the plurality of coils comprises at least four coils.

7. The haptic actuator of claim 1 wherein the controller determines the position of the field member along an x-axis dimension, a z-axis dimension, and a rotational dimension.

8. The haptic actuator of claim 1 wherein the controller is configured to drive each of the plurality of coils based upon the position of the field member in the plurality of dimensions.

9. The haptic actuator of claim 1 wherein the controller is configured to sense and drive each coil at a same time.

10. The haptic actuator of claim 1 wherein the controller is configured to sense and drive each coil at a different time.

11. The haptic actuator of claim 1 wherein the field member has opposing first and second sides; and further comprising a respective at least one flexure bearing mounting each of the first and second sides of the field member to be reciprocally movable within the housing responsive to the plurality of coils.

12. The haptic actuator of claim 11 wherein the respective at least one flexure bearing has a wishbone shape.

13. The haptic actuator of claim 1 wherein each coil has a racetrack shape.

14. The haptic actuator of claim 1 wherein the at least one permanent magnet comprises a plurality of permanent magnets.

15. A haptic actuator comprising:
a housing;
at least four coils carried within the housing;
a field member moveable within the housing between the at least four coils and comprising at least one permanent magnet; and
a controller coupled to the at least four coils and configured to
sense a respective back electromotive force (EMF) value of each of the at least four coils,
determine a position of the field member in a plurality of dimensions based upon the back EMF values and motor constant values, and
drive each of the at least four coils based upon the position of the field member in the plurality of dimensions.

16. The haptic actuator of claim 15 wherein the housing has a top and bottom; wherein the at least four coils comprise a plurality of coil pairs, each coil pair comprising top and bottom opposing coils, the motor constant values corresponding to respective motor constant values associated with each coil pair; and wherein the controller is configured to sense the respective back EMF value of each coil pair.

17. The haptic actuator of claim 15 wherein the housing has a top and bottom; wherein the at least four coils comprise a plurality of coil pairs, each coil pair comprising top and bottom opposing coils; and wherein the controller is configured to sense the respective back EMF value of at least one coil pair while driving at least one other coil pair.

18. The haptic actuator of claim 15 wherein the housing has a top and bottom; wherein the at least four coils comprise a plurality of coil pairs, each coil pair comprising left and right opposing coils, the motor constant values corresponding to respective motor constant values associated with each coil pair; and wherein the controller is configured to sense the respective back EMF value of each coil pair.

19. The haptic actuator of claim 15 wherein the controller determines the position of the field member along an x-axis dimension, a z-axis dimension, and a rotational dimension.

20. A method of using a haptic actuator comprising a housing, a plurality of coils carried within the housing, and a field member moveable within the housing between the plurality of coils and comprising at least one permanent magnet, the method comprising:
using a controller coupled to the plurality of coils to
sense a respective back electromotive force (EMF) value of each of the plurality of coils, and
determine a position of the field member in a plurality of dimensions based upon the back EMF values and motor constant values.

21. The method of claim 20 wherein the housing has a top and bottom; wherein the plurality of coils comprises a plurality of coil pairs, each coil pair comprising top and bottom opposing coils, the motor constant values corresponding to respective motor constant values associated with each coil pair; and wherein the controller is used to sense the respective back EMF value of each coil pair.

22. The method of claim 20 wherein the housing has a top and bottom; wherein the plurality of coils comprises a plurality of coil pairs, each coil pair comprising top and bottom opposing coils; and wherein the controller is used to sense the respective back EMF value of at least one coil pair while driving at least one other coil pair.

23. The method of claim 20 wherein the housing has a top and bottom; wherein the plurality of coils comprises a plurality of coil pairs, each coil pair comprising left and right opposing coils, the motor constant values corresponding to respective motor constant values associated with each coil pair; and wherein the controller is used to sense the respective back EMF value of each coil pair.

24. The method of claim 20 wherein the housing has a top and bottom; wherein the plurality of coils comprises at least

Assignees

• Apple Inc

Inventors

• Hajati Arman
• Yanagisawa Kayo

Classifications

• H02N2/028

  along multiple or arbitrary translation directions, e.g. XYZ stages · CPC title

• H01F7/1638

  Armatures not entering the winding · CPC title

• H01F41/064

  Winding non-flat conductive wires, e.g. rods, cables or cords · CPC title

• G06F3/016 Primary

  Input arrangements with force or tactile feedback as computer generated output to the user · CPC title

• H01F7/1653

  Magnetic circuit having axially spaced pole-pieces · CPC title