Compensating for lead-lag in rotor system

Patent metadata

Field	Value
Publication number	US-9266608-B2
Application number	US-201313846113-A
Country	US
Kind code	B2
Filing date	Mar 18, 2013
Priority date	Mar 18, 2013
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A control system for a rotor assembly includes a plurality of sensors configured to detect a lead-lag rate of each rotor blade of a plurality of rotor blades rotatable around a shaft and a flight control computer configured to generate lead-lag compensation signals based on the detected lead rate and lag rate of each rotor blade to control each rotor blade.

First claim

What is claimed is:

1. A control system for a rotor assembly comprising:
a plurality of sensors configured to detect a lead-lag rate of each rotor blade of a plurality of rotor blades rotatable around a shaft; and
a flight control computer configured to generate lead-lag compensation signals based on the detected lead rate and lag rate of each rotor blade to control each rotor blade;
wherein the flight control computer is configured to convert the detected lead-lag rate of each rotor blade into a composite longitudinal lead-lag rate signal and a composite lateral lead-lag rate signal by performing an individual blade coordinate to multi-blade coordinate conversion;
wherein the flight control computer is configured to generate a filtered longitudinal lead-lag rate signal and a filtered lateral lead-lag rate signal by passing the composite longitudinal lead-lag rate signal and the composite lateral lead-lag rate signal through a regressive lag mode band-pass filter and a progressive lag mode variable band-pass filter, and
the flight control computer is configured to generate the lead-lag compensation signals based on the filtered longitudinal lead-lag rate signal and the filtered lateral lead-lag rate signal.

2. The rotor assembly of claim 1 , wherein the flight control computer is configured to detect a rotational rotor rate of the plurality of rotor blades, to generate band-pass filter coefficients by passing the rotational rotor rate through a regressive lag mode-progressive lag mode frequency calculator, and to provide the band-pass filter coefficients to the regressive lag mode band-pass filter and the progressive lag mode variable band-pass filter, respectively.

3. The rotor assembly of claim 1 , wherein the flight control computer is configured to generate the lead-lag compensation signals by passing the filtered longitudinal lead-lag rate signal and the filtered lateral lead-lag rate signal through a transformation matrix to combine portions of the filtered longitudinal lead-lag rate signal and the filtered lateral lead lag rate signal.

4. The rotor assembly of claim 1 , further comprising a swashplate to control a position of the plurality of rotor blades,
wherein the flight control computer is configured to generate swashplate control signals based on the lead-lag compensation signals.

5. A rotor control assembly, comprising:
a rotor control computer configured to receive as inputs detected lead-lag rates from sensors located on a plurality of rotor blades rotating around a rotor shaft, to generate a lead-lag compensation signal based on the measured lead-lag rates, and to generate a rotor blade control signal based on the lead-lag compensation signal;
wherein the rotor control computer is configured to convert the detected lead-lag rate of each rotor blade into a composite longitudinal lead-lag rate signal and a composite lateral lead-lag rate signal by performing an individual blade coordinate to multi-blade coordinate conversion;
wherein the rotor control computer is configured to generate a filtered longitudinal lead-lag rate signal and a filtered lateral lead-lag rate signal by passing the composite longitudinal lead-lag rate signal and the composite lateral lead-lag rate signal through a regressive lag mode band-pass filter and a progressive lag mode variable band-pass filter, and
the flight control computer is configured to generate the lead-lag compensation signals based on the filtered longitudinal lead-lag rate signal and the filtered lateral lead-lag rate signal.

6. The rotor control assembly of claim 5 , wherein the rotor control computer is configured to detect a rotational rotor rate of the plurality of rotor blades, to generate band-pass filter coefficients by passing the rotational rotor rate through a regressive lag mode-progressive lag mode frequency calculator, and to provide the band-pass filter coefficients to the regressive lag mode band-pass filter and the progressive lag mode variable band-pass filter, respectively.

7. The rotor control assembly of claim 5 , wherein the rotor control computer is configured to generate the lead-lag compensation signals by passing the filtered longitudinal lead-lag rate signal and the filtered lateral lead-lag rate signal through an identity matrix to combine portions of the filtered longitudinal lead-lag rate signal and the filtered lateral lead lag rate signal.

8. The rotor control assembly of claim 5 , wherein the rotor control computer is configured to generate swashplate control signals based on the lead-lag compensation signals, the swashplate control signals controlling a position of the plurality of rotor blades.

9. A method of controlling a rotor system, the method comprising:
detecting a lead-lag rate of each of a plurality of rotor blades;
generating a lead-lag compensation signal based on the detected lead-lag rate; and
controlling the plurality of rotor blades based on the lead-lag compensation signal;
wherein generating the lead-lag compensation signal includes converting the calculated lead-lag rate of each rotor blade into a composite longitudinal lead-lag rate signal and a composite lateral lead-lag rate signal by performing an individual blade coordinate to multi-blade coordinate conversion;
wherein generating the lead-lag compensation signal comprises:
generating a filtered longitudinal lead-lag rate signal and a filtered lateral lead-lag rate signal by passing the composite longitudinal lead-lag rate signal and the composite lateral lead-lag rate signal through a regressive lag mode band-pass filter and a progressive lag mode variable band-pass filter; and
generating the lead-lag compensation signals based on the filtered longitudinal lead-lag rate signal and the filtered lateral lead-lag rate signal.

10. The method of claim 9 , wherein generating the lead-lag compensation signal further comprises:
detecting a rotational rotor rate of the plurality of rotor blades;
generating band-pass filter coefficients by passing the rotational rotor rate through a regressive lag mode-progressive lag mode frequency calculator; and
providing the band-pass filter coefficients to the regressive lag mode band-pass filter and the progressive lag mode variable band-pass filter, respectively.

11. The method of claim 9 , wherein generating the lead-lag compensation signal further comprises:
generating a mixed longitudinal lead-lag rate signal and a mixed lateral lead-lag rate signal by passing the filtered longitudinal lead-lag rate signal and the filtered lateral lead-lag rate signal through an identity matrix to mix the filtered longitudinal lead-lag rate signal with the filtered lateral lead lag rate signal; and
generating the lead-lag compensation signals based on the mixed longitudinal lead-lag rate signal and the mixed lateral lead-lag rate signal.

12. The method of claim 9 , further comprising:
controlling a swashplate of the rotor system based on the lead-lag compensation signals.

13. A computer readable medium encoded with processing instructions to implement the method of claim 9 using one or more processors.

14. A rotary wing aircraft comprising a fuselage, a rotor assembly connected to the fuselage, and the control system of claim 1 to control the blades rotating about the shaft of the rotor assembly.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Sahasrabudhe Vineet
• White Matthew A

Classifications

• B64C27/57 Primary

  automatic or condition responsive, e.g. responsive to rotor speed, torque or thrust · CPC title

• B64C27/605

  including swash plate, spider or cam mechanisms · CPC title

• B64C27/635

  specially for controlling lag-lead movements of blades · CPC title