Accelerometer-aided gyroscope

• US 9,194,707 B2
• Filed: 11/14/2013
• Issued: 11/24/2015
• Est. Priority Date: 02/15/2010
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Pande, Tarkesh, Waters, Deric W
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Malhotra, Sanjeev
• Application Number:
  US14/079,870
• Publication Number:
  US 20140290398A1
• Time in Patent Office: 740 Days
• Field of Search: 701/41, 701/45, 701/216, 700/66, 702/96, 702/193, 73/13.7, 733/82.G, 735/79, 303/7, 340/680, 600/595, 623/10
• US Class Current: 1/1
• CPC Class Codes: G01C 19/04 Details
• CPC Class Codes: G01C 21/185 for gravity
• CPC Class Codes: Y10T 74/1229 Gyroscope control

Abstract

A method comprises computing a metric based on the accelerometer signal to remove an acceleration due to gravity. A bandwidth of a gyroscope filter is set based on the accelerometer signal and the computed metric. The gyroscope filter uses a low-pass filter to filter a signal from the gyroscope.

Claims

1. A method, comprising:

computing a metric based on a multi-axis accelerometer signal to remove an acceleration due to gravity, wherein the multi-axis accelerometer signal comprising a separate, single axis accelerometer signal corresponding to each axis of the accelerometer;

setting a bandwidth of a hardware gyroscope filter based on only a subset of the single-axis accelerometer signals and the computed metric;

low-pass filtering, by said hardware gyroscope filter, a signal from a multi-axis gyroscope;

wherein setting the bandwidth of the hardware gyroscope filter comprises determining whether the only a subset of the single-axis accelerometer signals is less than or greater than threshold; and

wherein computing the metric comprises computing at least one of variances of the only a subset of the single-axis accelerometer signals, standard deviations of the only a subset of the single-axis accelerometer signals, and a square root of a value based on the only a subset of the single-axis accelerometer signals less a gravitational constant.

2. The method of claim 1, wherein setting bandwidth of the hardware gyroscope filter comprises setting the bandwidth to a lower bandwidth based on the only a subset of the single-axis accelerometer signals being less than the threshold and to a higher bandwidth based on the accelerometer signal being greater than the threshold.

3. The method of claim 1, wherein setting the bandwidth of the hardware gyroscope filter comprises comparing the only a subset of the single-axis accelerometer signals to lower and upper thresholds.

4. The method of claim 3, further comprising transitioning the gyroscope to a low power state including at least one of an off state and a sleep mode based on the only a subset of the single-axis accelerometer signals being less than the lower threshold.

5. The method of claim 3, wherein setting the bandwidth of the hardware gyroscope filter comprises setting the bandwidth to a lower bandwidth based on the only a subset of the single-axis accelerometer signals being between the lower and upper thresholds and to a higher bandwidth based on the accelerometer signal being greater than the upper threshold.