Combining electropermanent magnets and magnetorheological fluid to modify an operation of an input device

1. A clutch assembly for an input device, the clutch assembly comprising:

an input shaft;

an output shaft,

wherein the input shaft and output shaft are in coaxial alignment, and

wherein the input shaft is coupled to the output shaft such that the input shaft and output shaft are configured for a rotational translation therebetween;

an electropermanent magnet (EPM) assembly including:

a permanent magnet configured to generate a magnetic field; and

a magnetizing assembly configured to set the magnetic field generated by the permanent magnet;

a chamber formed between the input shaft and output shaft;

magnetorheological (MR) material contained within the chamber,

wherein the MR material has a viscosity that changes based on the magnetic field, and

wherein the MR material is configured to provide a frictional resistance to the rotational translation between the input shaft and output shaft, the resistance based on the viscosity of the MR material.

2. The clutch assembly of claim 1 wherein the clutch assembly is configured to operate in a plurality of modes of operation including:

a first mode of operation where the magnetizing assembly sets the magnetic field of the permanent magnet such that the MR material has a first viscosity that provides a first resistance to the rotational translation between the input shaft and output shaft; and

a second mode of operation where the magnetizing assembly sets the magnetic field of the permanent magnet such that the MR material has a second viscosity that provides a second resistance to the rotational translation between the input shaft and output shaft;

wherein the second resistance is greater than the first resistance.

3. The clutch assembly of claim 2 further comprising a second permanent magnet configured to generate a second magnetic field,

wherein in the first mode of operation, the permanent magnet and the second permanent magnet are magnetized such that a path of magnetic conduction of their corresponding magnetic fields is substantially contained by the permanent magnet and second permanent magnet and does not pass through the MR material, and

wherein in the second mode of operation, the permanent magnet and the second permanent magnet are magnetized such that the path of magnetic conduction of their corresponding magnetic fields pass through the MR material.

4. The clutch assembly of claim 2 wherein the first viscosity has a low resistance causing a weak frictional resistance between the input shaft and output shaft allowing the input and output shafts to freely rotate with respect to each other.

5. The clutch assembly of claim 2 wherein the second viscosity has a high resistance causing a strong frictional resistance between the input shaft and output shaft preventing the input and output shafts from rotating with respect to each other.

6. The clutch assembly of claim 2 wherein the input shaft includes a first plurality of plates, wherein the output shaft includes a second plurality of plates, wherein the first plurality of plates and the second plurality of plates are interleaved and configured adjacent to the MR material thereby providing an increased frictional resistance between the input shaft and output shaft when the clutch assembly is in the second mode of operation.

7. The clutch assembly of claim 1 wherein the input shaft is substantially contained by the output shaft.

8. The clutch assembly of claim 1 wherein the clutch assembly is coupled to a rotary element on an input device.

9. The clutch assembly of claim 8 wherein the input device is a computer mouse.

10. The clutch assembly of claim 8 wherein the input device is a keyboard device.

11. A method of operating a clutch assembly, the method comprising:

receiving input data corresponding to a mode of operation of the clutch assembly, the mode of operation corresponding to a control of a frictional resistance between an input shaft and an output shaft of the clutch assembly that are in coaxial alignment, wherein the input shaft and output shaft are configured for a rotational translation therebetween;

determining a selection of the mode of operation based on the input data;

in response to the input data corresponding to a first mode of operation:

causing a magnetizing assembly to set a first magnetic field intensity of a permanent magnet that controls a viscosity of MR material configured between the input shaft and output shaft, the MR material under the first magnetic field intensity providing a first frictional resistance to the rotational translation between the input shaft and output shaft; and

in response to the input data corresponding to a second mode of operation:

causing a magnetizing assembly to set a second magnetic field intensity of the permanent magnet, the MR material under the second magnetic field intensity providing a second frictional resistance to the rotational translation between the input shaft and output shaft, the first and second resistance based on the viscosity of the MR material, wherein the second magnetic field intensity is higher than the first magnetic field intensity.

12. The method of claim 11 wherein in the first mode of operation the MR material has a minimum viscosity, and wherein in the second mode of operation the MR material has a maximum viscosity.

13. The method of claim 11 further comprising a second permanent magnet configured to generate a second magnetic field,

wherein in the first mode of operation, the permanent magnet and the second permanent magnet are magnetized such that a path of magnetic conduction of their corresponding magnetic fields is substantially contained by the permanent magnet and second permanent magnet and does not pass through the MR material, and

wherein in the second mode of operation, the permanent magnet and the second permanent magnet are magnetized such that the path of magnetic conduction of their corresponding magnetic fields pass through the MR material.

14. The method of claim 11 wherein the viscosity of the MR material during the first mode of operation has a low resistance causing a weak frictional resistance between the input shaft and output shaft allowing the input and output shafts to freely rotate with respect to each other.

15. The method of claim 11 wherein the viscosity of the MR material during the second mode of operation has a high resistance causing a strong frictional resistance between the input shaft and output shaft preventing the input and output shafts from rotating with respect to each other.

16. The method of claim 11 wherein the input shaft includes a first plurality of plates, wherein the output shaft includes a second plurality of plates, wherein the first plurality of plates and the second plurality of plates are interleaved and configured adjacent to the MR material thereby providing an increased frictional resistance between the input shaft and output shaft when the clutch assembly is in the second mode of operation.

17. The method of claim 11 wherein the input shaft is substantially contained by the output shaft.

18. The method of claim 11 wherein the clutch assembly is coupled to a scroll wheel on an input device.

19. The method of claim 18 wherein the input device is a computer mouse.

20. The method of claim 18 wherein the input device is a keyboard device.