ROTOR SYSTEM HEALTH MONITORING USING SHAFT LOAD MEASUREMENTS AND VIRTUAL MONITORING OF LOADS

• US 20100219987A1
• Filed: 02/28/2010
• Published: 09/02/2010
• Est. Priority Date: 03/02/2009
• Status: Active Grant

• Current Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Original Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Inventors: Morris, Brian Edward, Isom, Joshua D.
• Granted Patent: US 9,240,083 B2
• Time in Patent Office: Days
• US Class Current: 340/946
• CPC Class Codes: G07C 5/0816 Indicating performance data, e.g. occurrence of a malfunction

Abstract

A method of real-time rotor fault detection includes measuring a set of loads to obtain measured signals and virtually monitoring the set of loads to obtain estimated signals. The estimated signals are subtracted from the measured signals to obtain residuals and the residuals are compared to a categorical model. A categorical output representative of a rotor fault is identified within the categorical model.

Claims

1. A method of real-time rotor system condition detection comprising:

measuring a set of loads to obtain measured signals;

virtually monitoring the set of loads to obtain estimated signals;

subtracting the estimated signals from the measured signals to obtain residuals;

comparing the residuals to a categorical model; and

identifying a categorical output representative of a rotor system condition within the categorical model.

2. A method as recited in claim 1, wherein the set of loads include:

main rotor shaft bending;

main rotor shaft shear; and

main rotor shaft torque.

3. A method as recited in claim 1, wherein the measured signals include a feature at a particular harmonic frequency.

4. A method as recited in claim 3, wherein the feature includes a magnitude.

5. A method as recited in claim 3, wherein the feature includes a phase angle.

6. A method as recited in claim 1, wherein the estimated signals include a feature at a particular harmonic frequency.

7. A method as recited in claim 6, wherein the feature includes a magnitude.

8. A method as recited in claim 6, wherein the feature includes a phase angle.

9. A method as recited in claim 1, wherein the set of loads are correlated with a reference signal to establish a phase angle.

10. A method as recited in claim 1, further comprising storing the categorical output within a health and usage monitoring system.

11. A method as recited in claim 1, further comprising generating a warning if the categorical output is anything but “

No Fault Present.”

12. A method to virtually monitor a load on a rotor system of a rotary wing aircraft comprising:

sampling at least one aircraft parameter once per main rotor revolution calculating coefficients for a set of predefined high-frequency waveforms from the at least one aircraft parameter;

multiplying each of the set of high-frequency waveforms by the coefficient to obtain a set of weighted waveforms; and

summing the weighted waveforms to produce an estimate of the load on the rotor system.

13. The method as recited in claim 12, wherein the at least one aircraft parameter includes at least one of pilot inputs, aircraft airspeed, aircraft altitude, aircraft attitude, and aircraft accelerations.

14. The method as recited in claim 12, wherein the set of high-frequency waveforms include at least 8 samples per main rotor revolution.

15. The method as recited in claim 12, wherein summing the weighted waveforms to produce the high frequency estimate of the load provides for virtual monitoring of the load to obtain an estimated quantity.

16. The method as recited in claim 15, wherein the virtual monitoring of the load to obtain an estimated quantity of main rotor shaft bending. 17 The method as recited in claim 15, wherein the virtual monitoring of the load to obtain an estimated quantity of main rotor shaft shear.

18. The method as recited in claim 15, wherein the virtual monitoring of the load to obtain an estimated quantity of main rotor shaft torque.

19. A system for real-time rotor system condition detection comprising:

a sensor system operable to measure a set of loads to obtain measured signals; and

a module operable to virtually monitoring the set of loads to obtain estimated signals and execute a real-time fault detection and isolation algorithm to subtract the estimated signals from the measured signals to obtain residuals and compare the residuals to a categorical model to identify a categorical output representative of a rotor system condition within the categorical model.

20. The system as recited in claim 19, further comprising a health and usage monitoring system in communication with said module.

21. The system as recited in claim 19, wherein said module is a portion of a health and usage monitoring system in communication with said module.