System and Method for Device Self-Calibration

• US 20130174636A1
• Filed: 01/04/2013
• Published: 07/11/2013
• Est. Priority Date: 01/06/2012
• Status: Active Grant

• Current Assignee: Sensor Platforms, Incorporated (Knowles Corporation)
• Original Assignee: Sensor Platforms, Incorporated (Knowles Corporation)
• Inventors: Joseph, Benjamin E.
• Granted Patent: US 9,459,276 B2
• Time in Patent Office: Days
• US Class Current: 73/1.41
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device

Abstract

A system, computer readable storage medium and method for calibrating sensors of a human interface device having a first accelerometer and a second accelerometer and the method includes calibrating the first accelerometer, calibrating the second accelerometer and calibrating a combined-sensor output that includes contributions from the first accelerometer and the second accelerometer to generate combined-sensor conversion values. The method further includes adjusting the calibration of the first accelerometer in accordance with the combined-sensor conversion values.

Claims

1. A method comprising:

at a device including a first accelerometer and a second accelerometer;

calibrating the first accelerometer;

calibrating the second accelerometer;

calibrating a combined-sensor output to generate combined-sensor conversion values for converting uncalibrated combined-sensor measurements of the combined-sensor output to calibrated combined-sensor measurements of the combined-sensor output, wherein the combined-sensor output includes contributions from the first accelerometer and the second accelerometer; and

adjusting the calibration of the first accelerometer in accordance with the combined-sensor conversion values.

2. The method of claim 1, wherein the combined-sensor output is based on a difference between measurements of the first accelerometer and measurements of the second accelerometer.

3. The method of claim 1, wherein calibrating the first accelerometer includes storing first-accelerometer conversion values for converting uncalibrated accelerometer measurements of the first accelerometer to calibrated accelerometer measurements of the first accelerometer.

4. The method of claim 1, wherein calibrating the second accelerometer includes storing second-accelerometer conversion values for converting uncalibrated accelerometer measurements of the second accelerometer to calibrated accelerometer measurements of the second accelerometer.

5. The method of claim 1, wherein:

calibrating the first accelerometer includes calibrating scale and/or offset of the first accelerometer; and

adjusting the calibration of the first accelerometer includes adjusting the calibration of skew and/or rotation of the first accelerometer.

6. The method of claim 1, further comprising adjusting the calibration of the second accelerometer in accordance with the calibrated combined-sensor output.

7. The method of claim 6, wherein:

calibrating the second accelerometer includes calibrating scale and/or offset of the second accelerometer; and

adjusting the calibration of the second accelerometer includes adjusting the calibration of skew and/or rotation of the second accelerometer.

8. The method of claim 6, wherein:

adjusting the calibration of the first accelerometer includes adjusting a respective first-accelerometer conversion value in accordance with a particular combined-sensor conversion value; and

adjusting the calibration of the second accelerometer includes adjusting a respective second-accelerometer conversion value that corresponds to the respective first-accelerometer conversation value in accordance with the particular combined-sensor conversion value.

9. The method of claim 1, wherein the operations of calibrating the first accelerometer, calibrating the second accelerometer and calibrating the combined sensor output are performed using sensor measurements from a same plurality of sample orientations.

10. The method of claim 9, wherein:

the device includes a magnetometer; and

the method further comprises, calibrating the magnetometer, wherein the magnetometer is calibrated using a set of measurements from a different plurality of sample orientations than the plurality of sample orientations used to calibrate the accelerometers.

11. The method of claim 1, wherein:

the device includes a magnetometer; and

calibrating the first accelerometer includes;

calibrating the magnetometer;

for each of a plurality of sample orientations;

generating a set of one or more calibrated magnetometer measurements via the magnetometer;

generating a set of one or more uncalibrated first accelerometer measurements; and

calibrating the first accelerometer using respective calibrated magnetometer measurements and corresponding respective uncalibrated first accelerometer measurements for one or more respective sample orientations of the plurality of sample orientations.

12. A device, comprising:

one or more processors;

a plurality of sensors including a first accelerometer and a second accelerometer;

memory; and

one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for;

calibrating the first accelerometer;

calibrating the second accelerometer;

calibrating a combined-sensor output to generate combined-sensor conversion values for converting uncalibrated combined-sensor measurements of the combined-sensor output to calibrated combined-sensor measurements of the combined-sensor output, wherein the combined-sensor output includes contributions from the first accelerometer and the second accelerometer; and

adjusting the calibration of the first accelerometer in accordance with the combined-sensor conversion values.

13. The device of claim 12, wherein:

calibrating the first accelerometer includes calibrating scale and/or offset of the first accelerometer; and

adjusting the calibration of the first accelerometer includes adjusting the calibration of skew and/or rotation of the first accelerometer.

14. The device of claim 12, wherein the one or more programs further comprise instructions for adjusting the calibration of the second accelerometer in accordance with the calibrated combined-sensor output.

15. The device of claim 12, wherein the operations of calibrating the first accelerometer, calibrating the second accelerometer and calibrating the combined sensor output are performed using sensor measurements from a same plurality of sample orientations.

16. The device of claim 12, wherein:

the device includes a magnetometer; and

calibrating the first accelerometer includes;

calibrating the magnetometer;

for each of a plurality of sample orientations;

generating a set of one or more calibrated magnetometer measurements via the magnetometer;

generating a set of one or more uncalibrated first accelerometer measurements; and

calibrating the first accelerometer using respective calibrated magnetometer measurements and corresponding respective uncalibrated first accelerometer measurements for one or more respective sample orientations of the plurality of sample orientations.

17. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computer system with one or more processors, cause the computer system to:

calibrate a first accelerometer;

calibrate a second accelerometer;

calibrating a combined-sensor output to generate combined-sensor conversion values for converting uncalibrated combined-sensor measurements of the combined-sensor output to calibrated combined-sensor measurements of the combined-sensor output, wherein the combined-sensor output includes contributions from the first accelerometer and the second accelerometer; and

adjust the calibration of the first accelerometer in accordance with the combined-sensor conversion values.

18. The non-transitory computer-readable storage medium of claim 17, wherein:

calibrating the first accelerometer includes calibrating scale and/or offset of the first accelerometer; and

adjusting the calibration of the first accelerometer includes adjusting the calibration of skew and/or rotation of the first accelerometer.

19. The non-transitory computer-readable storage medium of claim 17, further comprising instructions to adjust the calibration of the second accelerometer in accordance with the calibrated combined-sensor output.

20. The non-transitory computer-readable storage medium of claim 17, wherein the operations of calibrating the first accelerometer, calibrating the second accelerometer and calibrating the combined sensor output are performed using sensor measurements from a same plurality of sample orientations.

21. The non-transitory computer-readable storage medium of claim 17, wherein:

the device includes a magnetometer; and

calibrating the first accelerometer includes;

calibrating the magnetometer;

for each of a plurality of sample orientations;

generating a set of one or more calibrated magnetometer measurements via the magnetometer;

generating a set of one or more uncalibrated first accelerometer measurements; and

calibrating the first accelerometer using respective calibrated magnetometer measurements and corresponding respective uncalibrated first accelerometer measurements for one or more respective sample orientations of the plurality of sample orientations.