Condition assessment and life expectancy prediction for devices

• US 7,024,335 B1
• Filed: 07/25/2003
• Issued: 04/04/2006
• Est. Priority Date: 04/15/1998
• Status: Expired due to Term

• Current Assignee: Texas A&M University System
• Original Assignee: Texas A&M University System
• Inventors: Parlos, Alexander G.
• Primary Examiner(s): Assouad, Patrick J.
• Application Number:
  US10/628,071
• Time in Patent Office: 984 Days
• Field of Search: 702/182, 702/183, 702/184, 702/185, 700/30, 700/31, 700/47, 700/48, 700/50, 700/52, 706/903, 706/906, 706/907, 706/914, 706/915
• US Class Current: 702/182
• CPC Class Codes: G05B 23/0254 based on a quantitative model, e.g. mathematical relationships between inputs and outputs; functions: observer, Kalman filter, residual calculation, Neural Networks
• CPC Class Codes: G05B 23/0283 Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06

Abstract

Assessing the condition of a device includes receiving signals from a sensor that makes electrical measurements of the device. An expected response of the device is estimated in accordance with the received signals, and a measured response of the device is established in accordance with the received signals. An output residual is calculated according to the expected response and the measured response. The condition of the device is assessed by identifying a fault of the device in accordance with the output residual.

Claims

1. A method for assessing the condition of a device, comprising:

receiving a plurality of signals from a sensor operable to make one or more electrical measurements of a device;

estimating an expected response of the device in accordance with the received signals by;

estimating a disturbance from the received signals; and

calculating the expected response in accordance with the disturbance;

establishing a measured response of the device in accordance with the received signals;

calculating an output residual according to the expected response and the measured response; and

assessing the condition of the device by identifying a fault of the device in accordance with the output residual.

2. The method of claim 1, wherein the device comprises an electric device.

3. The method of claim 1, wherein the device comprises an electric motor.

4. The method of claim 1, further comprising monitoring the one or more electrical measurements of the device to generate the plurality of signals.

5. The method of claim 1, wherein:

the received signals comprise one or more measured inputs to the device and one or more measured outputs from the device; and

estimating the expected response of the device in accordance with the received signals further comprises;

estimating a disturbance of the received signals;

decoupling a first effect of the one or more measured inputs on the one or more measured outputs and a second effect of the disturbance on the one or more measured outputs; and

estimating the expected response of the device according to the first effect and the second effect.

6. The method of claim 1, further comprising extracting a spatio-temporal feature from the output residual.

7. The method of claim 1, further comprising extracting a spatio-temporal feature from the one or more electrical measurements.

8. The method of claim 1, further comprising classifying the fault to assess the condition of the device.

9. The method of claim 1, further comprising:

receiving an indicator corresponding to a life expectancy of the device; and

estimating the life expectancy associated with the device in accordance with the condition of the device and the indicator.

10. The method of claim 1, further comprising:

receiving an indicator corresponding to a life expectancy of the device;

estimating the life expectancy associated with the device in accordance with the condition of the device and the indicator; and

calculating an uncertainty associated with the estimated life expectancy.

33. The method of claim 1, wherein the device comprises a generator.

34. The method of claim 1, wherein the device comprises motor-driven equipment.

11. A system for assessing the condition of a device, comprising:

a sensor operable to make one or more electrical measurements of a device to generate a plurality of signals; and

a processor coupled to the sensor and operable to;

estimate an expected response of the device in accordance with the signals by;

estimating a disturbance from the signals; and

calculating the expected response in accordance with the disturbance;

establish a measured response of the device in accordance with the signals;

calculate an output residual according to the expected response and the measured response; and

assess the condition of the device by identifying a fault of the device in accordance with the output residual.

12. The system of claim 11;

wherein the device comprises an electric device.

13. The system of claim 11;

wherein the device comprises an electric motor.

14. The system of claim 11 the sensor further operable to monitor the one or more electrical measurements of the device to generate the plurality of signals.

15. The system of claim 11, wherein:

the signals comprise one or more measured inputs to the device and one or more measured outputs from the device; and

the processor is operable to estimate the expected response of the device in accordance with the signals by;

estimating a disturbance of the signals;

decoupling a first effect of the one or more measured inputs on the one or more measured outputs and a second effect of the disturbance on the one or more measured outputs; and

estimating the expected response of the device according to the first effect and the second effect.

16. The system of claim 11, the processor further operable to extract a spatio-temporal feature from the output residual.

17. The system of claim 11, the processor further operable to extract a spatio-temporal feature from the one or more electrical measurements.

18. The system of claim 11, the processor further operable to classify the fault to assess the condition of the device.

19. The system of claim 11, the processor further operable to:

receive an indicator corresponding to a life expectancy of the device; and

estimate the life expectancy associated with the device in accordance with the condition of the device and the indicator.

20. The system of claim 11, the processor further operable to:

receive an indicator corresponding to a life expectancy of the device;

estimate the life expectancy associated with the device in accordance with the condition of the device and the indicator; and

calculate an uncertainty associated with the estimated life expectancy.

35. The system of claim 11, wherein the device comprises a generator.

36. The system of claim 11, wherein the device comprises motor-driven equipment.

21. Computer-implemented logic for assessing the condition of a device, the logic embodied in a medium and operable to:

receive a plurality of signals from a sensor operable to make one or more electrical measurements of a device;

estimate an expected response of the device in accordance with the received signals by;

estimating a disturbance from the received signals; and

calculating the expected response in accordance with the disturbance;

establish a measured response of the device in accordance with the received signals;

calculate an output residual according to the expected response and the measured response; and

assess the condition of the device by identifying a fault of the device in accordance with the output residual.

22. The logic of claim 21, wherein the device comprises an electric device.

23. The logic of claim 21, wherein the device comprises an electric motor.

24. The logic of claim 21, further operable to monitor the one or more electrical measurements of the device to generate the plurality of signals.

25. The logic of claim 21, wherein:

the received signals comprise one or more measured inputs to the device and one or more measured outputs from the device; and

the logic further operable to estimate the expected response of the device in accordance with the received signals by;

estimating a disturbance of the received signals;

decoupling a first effect of the one or more measured inputs on the one or more measured outputs and a second effect of the disturbance on the one or more measured outputs; and

estimating the expected response of the device according to the first effect and the second effect.

26. The logic of claim 21, further operable to extract a spatio-temporal feature from the output residual.

27. The logic of claim 21, further operable to extract a spatio-temporal feature from the one or more electrical measurements.

28. The logic of claim 21, further operable to classify the fault to assess the condition of the device.

29. The logic of claim 21, further operable to:

receive an indicator corresponding to a life expectancy of the device; and

estimate the life expectancy associated with the device in accordance with the condition of the device and the indicator.

30. The logic of claim 21, further operable to:

receive an indicator corresponding to a life expectancy of the device;

estimate the life expectancy associated with the device in accordance with the condition of the device and the indicator; and

calculate an uncertainty associated with the estimated life expectancy.

37. The logic of claim 21, wherein the device comprises a generator.

38. The logic of claim 21, wherein the device comprises motor-driven equipment.

31. A system for assessing the condition of a device, comprising:

means for receiving a plurality of signals from a sensor operable to make one or more electrical measurements of a device;

means for estimating an expected response of the device in accordance with the received signals by;

estimating a disturbance from the received signals; and

calculating the expected response in accordance with the disturbance;

means for establishing a measured response of the device in accordance with the received signals;

means for calculating an output residual according to the expected response and the measured response; and

means for assessing the condition of the device by identifying a fault of the device in accordance with the output residual.

32. A method for assessing the condition of a device, comprising:

monitoring at a sensor one or more electrical measurements of a device to generate a plurality of signals, the device comprising an electric device comprising an electric motor;

receiving the plurality of signals from the sensor, the received signals comprising one or more measured inputs to the device and one or more measured outputs from the device;

estimating an expected response of the device in accordance with the received signals by;

estimating a disturbance of the received signals;

decoupling a first effect of the one or more measured inputs on the one or more measured outputs and a second effect of the disturbance on the one or more measured outputs; and

estimating the expected response of the device according to the first effect and the second effect;

establishing a measured response of the device in accordance with the received signals;

calculating an output residual according to the expected response and the measured response;

assessing the condition of the device by identifying a fault of the device in accordance with the output residual by;

extracting a first spatio-temporal feature from the output residual; and

extracting a second spatio-temporal feature from the one or more measurements; and

classifying the fault to assess the condition of the device;

receiving an indicator corresponding to a life expectancy of the device;

estimating the life expectancy associated with the device in accordance with the condition of the device and the indicator; and

calculating an uncertainty associated with the estimated life expectancy.