System and method for inertial sensor offset compensation

• US 9,121,866 B2
• Filed: 03/15/2013
• Issued: 09/01/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Arriver Software LLC
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Demerly, Jon D.
• Primary Examiner(s): Macchiarolo, Peter
• Assistant Examiner(s): HULS, NATALIE F
• Application Number:
  US13/837,088
• Publication Number:
  US 20140260517A1
• Time in Patent Office: 900 Days
• Field of Search: 73/13.7, 73/13.8, 702/104
• US Class Current: 1/1
• CPC Class Codes: B60G 2600/082 Sensor drift
• CPC Class Codes: B60R 16/0233 Vehicle tilting, overturning or roll over
• CPC Class Codes: B60T 2250/06 Sensor zero-point adjustment; Offset compensation
• CPC Class Codes: B60W 2050/005 Sampling
• CPC Class Codes: B60W 2050/0052 Filtering, filters
• CPC Class Codes: B60W 2050/0215 Sensor drifts or sensor failures
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 40/10 related to vehicle motion
• CPC Class Codes: B60W 40/11 Pitch movement
• CPC Class Codes: B60W 40/112 Roll movement
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B60W 50/0205 Diagnosing or detecting failures; Failure detection models
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning
• 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

Abstract

The present invention provides an improved method and system for compensation of inertial sensors. In one implementation a modified moving average is applied to provide dynamic offset compensation for an inertial sensor output that is calculated when a vehicle is in motion.

Claims

1. A sensor compensation system for a motor vehicle comprising:

an inertial sensor configured to measure a rate of a vehicle;

a processing unit in communication with the inertial sensor;

a memory unit operably coupled to the processing unit; and

the processing unit including at least one module configured to;

sample a series of data from the inertial sensor;

calculate a modified moving average from the series of data and a current data sample from the series of data to calculate a compensation offset, wherein the modified moving average is an average based on a previously determined average; and

filter the compensation offset from the series of data to generate a compensated rate signal, wherein the memory unit stores a current average from the modified moving average to calculate a subsequent modified moving average for the series of data; and

wherein the modified moving averages, A_k, for the sampled inertial sensor output, x_k, where k is the sample number and n is the number of samples for a moving average window is determined by the following equations;

2. The sensor compensation system of claim 1, wherein the series of data is sampled when the vehicle is in motion.

3. The sensor compensation system of claim 1, wherein the inertial sensor is an angular rate sensor.

4. The sensor compensation system of claim 1, further comprising a second sensor configured to detect motion of the vehicle in communication with the processor.

5. The sensor compensation system of claim 4, wherein the second sensor configured to detect motion is a wheel speed sensor.

6. The sensor compensation system of claim 4, wherein the second sensor configured to detect motion is an accelerometer.

7. The sensor compensation system of claim 4, wherein the at least one module is configured to calculate a dynamic modified moving average in response to a signal from the sensor configured to detect motion.

8. The sensor compensation system of claim 7, wherein the at least one module is configured to calculate a transition modified moving average between the static modified moving average and the dynamic modified moving average to calculate the compensation offset.

9. The sensor compensation system of claim 4, wherein the at least one module is configured to calculate a static modified moving average in response to a signal from the sensor configured to detect motion.

10. A method of compensation for an inertial sensor comprising:

measuring a rate signal of a motor vehicle;

calculating an inertial sensor compensation offset including;

sampling a series of data from the rate signal;

calculating a dynamic modified moving average from the series of data measured in response to the vehicle in motion, and a static modified moving average in response the vehicle being stopped to calculate a compensation offset, wherein the static and dynamic modified moving averages are each an average based on a previously determined average;

filtering the compensation offset from the rate signal; and

generating a compensated rate signal; and

wherein each of the static and dynamic modified moving averages, A_k, for the sampled inertial sensor output, x_k, where k is the sample number and n is the number of samples for a moving average window is determined by the following equations;

11. The method of claim 10, further comprising calculating a transition modified moving average between the static modified moving average and the dynamic modified moving average to calculate the compensation offset.

12. The method of claim 10, wherein the modified moving average is filtered by a low pass filtering process.

13. The method of claim 10, wherein the dynamic modified moving average is filtered separately from the static modified moving average.