Spatio-temporal filter for structural health monitoring

• US 20060265146A1
• Filed: 05/19/2005
• Published: 11/23/2006
• Est. Priority Date: 05/19/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Gordon, Grant A., Gorinevsky, Dimitry
• Granted Patent: US 7,222,027 B2
• Time in Patent Office: Days
• US Class Current: 702/39
• CPC Class Codes: G05B 2219/45071 Aircraft, airplane, ship cleaning manipulator, paint stripping
• CPC Class Codes: G05B 23/0221 Preprocessing measurements, e.g. data collection rate adjustment; Standardization of measurements; Time series or signal analysis, e.g. frequency analysis or wavelets; Trustworthiness of measurements; Indexes therefor; Measurements using easily measured parameters to estimate parameters difficult to measure; Virtual sensor creation; De-noising; Sensor fusion; Unconventional preprocessing inherently present in specific fault detection methods like PCA-based methods

Abstract

A method for estimating damage to a structure is provided. The method comprises collecting a plurality of damage estimates over time and filtering the plurality of damage estimates with spatio-temporal filters. The method also comprises generating an enhanced damage estimate based on the filtered damage estimate.

Claims

1. A method for estimating damage to a structure, the method comprising:

collecting a plurality of damage estimates over time;

filtering the plurality of damage estimates with spatio-temporal filters; and

generating an enhanced damage estimate based on the filtered damage estimate.

2. The method of claim 1, wherein filtering the plurality of damage estimates comprises:

forming a filtered structure damage estimate; and

forming an actual structure damage estimate.

3. The method of claim 2, further comprising:

updating the filtered structure damage estimate; and

updating the actual structure damage estimate.

4. The method of claim 3, wherein updating the actual structure damage estimate comprises:

computing a difference between the damage estimate and the filtered structure damage estimate computed at the previous update step;

performing a first convolution of the difference between the damage estimate and the filtered structure damage estimate with a feedback gain operator;

performing a second convolution of the actual structure damage estimate computed at the previous update step with a smoothing operator; and

combining the first and second convolution results and the actual structure damage estimate computed at the previous update step to obtain an updated actual structure damage estimate.

5. The method of claim 2, wherein filtering the plurality of damage estimates with spatio-temporal filters comprises:

performing a convolution of the actual structure damage estimate with a blur operator to form a filtered damage estimate.

6. A damage estimate system, the system comprising:

at least one sensor that collects damage estimate data as scans of the structure state;

a processing unit that receives the scans from the at least one sensor and generates a damage estimate from each scan; and

wherein the processing unit applies spatio-temporal filtering to the scans to produce an enhanced damage estimate.

7. The system of claim 6, further comprising:

at least one sensor data concentrator adapted to receive the scans from the at least one sensor and digitize the scans.

8. The system of claim 6, further comprising:

a memory adapted to receive the damage estimates for each scan from the processing unit.

9. The system of claim 6, wherein the at least one sensor uses at least one of acoustic emission sensing, ultrasonic Lamb wave sensing, electrical conductivity sensing, and strain field sensing.

10. A machine-readable medium having instructions embodied thereon for a method for estimating damage to a structure, the method comprising:

collecting a plurality of damage estimates over time;

filtering the plurality of damage estimates with spatio-temporal filters; and

generating an enhanced damage estimate based on the filtered damage estimate.

11. The machine-readable medium of claim 10, wherein filtering the plurality of damage estimates comprises:

forming a filtered structure damage estimate; and

forming an actual structure damage estimate.

12. The machine-readable medium of claim 11, further comprising:

updating the filtered structure damage estimate; and

updating the actual structure damage estimate.

13. The machine-readable medium of claim 12, wherein updating the actual structure damage estimate comprises:

computing a difference between the damage estimate and the filtered structure damage estimate computed at the previous update step;

performing a first convolution of the difference between the damage estimate and the filtered structure damage estimate with a feedback gain operator;

performing a second convolution of the actual structure damage estimate computed at the previous update step with a smoothing operator; and

combining the first and second convolution results and the actual structure damage estimate computed at the previous update step to obtain an updated actual structure damage estimate.

14. The machine-readable medium of claim 11, wherein filtering the plurality of damage estimates with spatio-temporal filters comprises:

performing a convolution of the actual structure damage estimate with a blur operator to form a filtered damage estimate.

15. A damage estimate system, the system comprising:

means for sensing damage in an object, the means for sensing having an output;

means for estimating the damage of the object from the output of the means for sensing; and

means for improving the accuracy of the means for estimating using multiple outputs generated by the means for sensing.