Eccentric rotating mass actuator optimization for haptic effects

1. A method of generating a haptic effect on a device using an Eccentric Rotating Mass (ERM) actuator, the method comprising:

determining a vibration level of the device during operation of the device;

receiving a haptic effect signal comprising one or more parameters, wherein one of the parameters is a voltage amplitude level as a function of time;

varying the voltage amplitude level based at least on vibration level; and

applying the varied haptic effect signal to the ERM actuator.

2. The method of claim 1 , wherein the device comprises an accelerometer that determines the vibration level.

3. The method of claim 1 , further comprising:

determining a back electromotive force (EMF) of the ERM actuator during operation of the device; and

varying the voltage amplitude level based at least on the back EMF.

4. The method of claim 3 , further comprising:

determining a rise time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the rise time.

5. The method of claim 3 , further comprising:

determining a brake time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the brake time.

6. The method of claim 1 , wherein the voltage amplitude level comprises an overdrive voltage.

7. The method of claim 3 , further comprising:

determining a relationship of an angular speed and the back EMF for the ERM actuator; and

varying the voltage amplitude level based at least on the relationship.

8. The method of claim 3 , further comprising:

using the back EMF to determine if the actuator is spinning.

9. A method of generating a haptic effect on a device using an Eccentric Rotating Mass (ERM) actuator, the method comprising:

determining by the device a back electromotive force (EMF) of the ERM actuator when the device is powered on;

receiving a haptic effect signal comprising one or more parameters, wherein one of the parameters is a voltage amplitude level as a function of time;

varying the voltage amplitude level based at least on the back EMF; and

applying the varied haptic effect signal to the ERM actuator.

10. The method of claim 9 , wherein the device comprises an accelerometer, further comprising:

determining using the accelerometer a vibration level of the device when the device is powered on.

11. The method of claim 9 , further comprising:

determining a rise time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the rise time.

12. The method of claim 9 , further comprising:

determining a brake time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the brake time.

13. The method of claim 9 , wherein the voltage amplitude level comprises an overdrive voltage.

14. The method of claim 9 , further comprising:

determining a relationship of an angular speed and the back EMF for the ERM actuator; and

varying the voltage amplitude level based at least on the relationship.

15. A non-transitory computer readable medium having instructions stored thereon that, when executed by a processor, cause the processor to generate a haptic effect on a device using an Eccentric Rotating Mass (ERM) actuator, the generating comprising:

determining a vibration level of the device during operation of the device;

receiving a haptic effect signal comprising one or more parameters, wherein one of the parameters is a voltage amplitude level as a function of time;

varying the voltage amplitude level based at least on vibration level; and

applying the varied haptic effect signal to the ERM actuator.

16. The non-transitory computer readable medium of claim 15 , wherein the device comprises an accelerometer that determines the vibration level.

17. The non-transitory computer readable medium of claim 15 , the generating further comprising:

determining a back electromotive force (EMF) of the ERM actuator during operation of the device; and

varying the voltage amplitude level based at least on the back EMF.

18. The non-transitory computer readable medium of claim 17 , further comprising:

determining a rise time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the rise time.

19. The non-transitory computer readable medium of claim 17 , further comprising:

determining a brake time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the brake time.

20. The non-transitory computer readable medium of claim 15 , wherein the voltage amplitude level comprises an overdrive voltage.

21. The non-transitory computer readable medium of claim 17 , the generating further comprising:

determining a relationship of an angular speed and the back EMF for the ERM actuator; and

varying the voltage amplitude level based at least on the relationship.

22. The non-transitory computer readable medium of claim 17 , further comprising:

using the back EMF to determine if the actuator is spinning.

23. A non-transitory computer readable medium having instructions stored thereon that, when executed by a processor, cause the processor to generate a haptic effect on a device using an Eccentric Rotating Mass (ERM) actuator, the generating comprising:

determining by the device a back electromotive force (EMF) of the ERM actuator when the device is powered on;

receiving a haptic effect signal comprising one or more parameters, wherein one of the parameters is a voltage amplitude level as a function of time;

varying the voltage amplitude level based at least on the back EMF; and

applying the varied haptic effect signal to the ERM actuator.

24. The non-transitory computer readable medium of claim 23 , wherein the device comprises an accelerometer, the generating further comprising:

determining using the accelerometer a vibration level of the device when the device is powered on.

25. The non-transitory computer readable medium of claim 23 , the generating further comprising:

determining a rise time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the rise time.

26. The non-transitory computer readable medium of claim 23 , the generating further comprising:

determining a brake time of the ERM actuator using the back EMF; and

varying the voltage amplitude level based at least on the brake time.

27. The non-transitory computer readable medium of claim 23 , wherein the voltage amplitude level comprises an overdrive voltage.

28. The non-transitory computer readable medium of claim 23 , the generating further comprising:

determining a relationship of an angular speed and the back EMF for the ERM actuator; and

varying the voltage amplitude level based at least on the relationship.