Rotor system structural fault estimation

Patent metadata

Field	Value
Publication number	US-2017073064-A1
Application number	US-201515309361-A
Country	US
Kind code	A1
Filing date	Mar 5, 2015
Priority date	May 7, 2014
Publication date	Mar 16, 2017
Grant date	—

Abstract

One aspect is a structural fault estimation system for a rotor system. The structural fault estimation system includes a plurality of sensors operable to provide a plurality of measured rotor loads and motion of the rotor system. A rotor loads and motion estimator is operable to produce a plurality of estimated rotor loads and motion for the rotor system. A rotor fault estimator is operable to determine residual rotor loads and motion as a difference between the measured rotor loads and motion and the estimated rotor loads and motion, and estimate fault magnitudes for the rotor system using least squares relative to fault models and the residual rotor loads and motion. The structural fault estimation system can perform structural fault estimation in real-time on an aircraft while in operation.

First claim

1 . A structural fault estimation system for a rotor system, the structural fault estimation system comprising:
a plurality of sensors operable to provide a plurality of measured rotor loads and motion of the rotor system; a rotor loads and motion estimator operable to produce a plurality of estimated rotor loads and motion for the rotor system; and a rotor fault estimator operable to determine residual rotor loads and motion as a difference between the measured rotor loads and motion and the estimated rotor loads and motion, and estimate fault magnitudes for the rotor system using least squares relative to fault models and the residual rotor loads and motion.

2 . The structural fault estimation system according to claim 1 , wherein the fault models comprise a library of fault signatures for a plurality of structural faults of the rotor system.

3 . The structural fault estimation system according to claim 1 , wherein the estimated rotor loads and motion for the rotor system are estimates based on an increased sampling frequency of aircraft state parameters.

4 . The structural fault estimation system according to claim 3 , wherein the aircraft state parameters are updated once per main rotor revolution of the rotor system.

5 . The structural fault estimation system according to claim 4 , wherein a sample rate of the estimated rotor loads and motion is normalized to align with a sample rate of the measured rotor loads and motion.

6 . The structural fault estimation system according to claim 1 , wherein the estimated fault magnitudes are isolated as separate fault conditions per rotor blade of the rotor system.

7 . The structural fault estimation system according to claim 1 , further comprising a fault detector that applies a cumulative sum detector to identify persistent fault changes over time for each of the estimated fault magnitudes.

8 . The structural fault estimation system according to claim 7 , wherein the cumulative sum detector declares a fault condition when a cumulative sum of a corresponding estimated fault magnitude exceeds a cumulative fault threshold.

9 . A method of rotor system structural fault estimation, the method comprising:
receiving a plurality of measured rotor loads and motion of a rotor system from a plurality of sensors; producing a plurality of estimated rotor loads and motion for the rotor system based on aircraft state parameters; determining residual rotor loads and motion as a difference between the measured rotor loads and motion and the estimated rotor loads and motion; and estimating fault magnitudes for the rotor system using least squares relative to fault models and the residual rotor loads and motion.

10 . The method according to claim 9 , wherein the fault models comprise a library of fault signatures for a plurality of structural faults of the rotor system.

11 . The method according to claim 9 , wherein the estimated rotor loads and motion for the rotor system are estimates based on an increased sampling frequency of the aircraft state parameters.

12 . The method according to claim 11 , wherein the aircraft state parameters are updated once per main rotor revolution of the rotor system.

13 . The method according to claim 12 , wherein a sample rate of the estimated rotor loads and motion is normalized to align with a sample rate of the measured rotor loads and motion.

14 . The method according to claim 9 , wherein the estimated fault magnitudes are isolated as separate fault conditions per rotor blade of the rotor system.

15 . The method according to claim 9 , further comprising:
applying a cumulative sum detector to identify persistent fault changes over time for each of the estimated fault magnitudes; and declaring a fault condition when a cumulative sum of a corresponding estimated fault magnitude exceeds a cumulative fault threshold.

16 . The method according to claim 9 , wherein the receiving a plurality of measured rotor loads and motion of a rotor system from a plurality of sensors includes preprocessing data from the sensors to produce the measured rotor loads and motion.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Isom Joshua D

Classifications

• G01M5/0016

  of aircraft wings or blades · CPC title

• G01L5/133

  for measuring thrust of propulsive devices, e.g. of propellers (aeroplanes B64C; marine propulsion B63H; jet-engines F02K) · CPC title

• B64C27/006 Primary

  Safety devices · CPC title

• G05B23/0221

  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 · CPC title

• G05B23/0224

  Process history based detection method, e.g. whereby history implies the availability of large amounts of data · CPC title