Full authority fly-by-wire pedal system

• US 20070205333A1
• Filed: 02/15/2006
• Published: 09/06/2007
• Est. Priority Date: 02/15/2006
• Status: Active Grant

• Current Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Original Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Inventors: Boczar, Bruce, Stiles, Lorren, Witiak, Peter
• Granted Patent: US 7,644,893 B2
• Time in Patent Office: Days
• US Class Current: 244/235
• CPC Class Codes: B64C 13/044 operated by feet, e.g. pedals
• CPC Class Codes: B64C 13/507 with artificial feel
• CPC Class Codes: B64C 27/56 characterised by the control initiating means, e.g. manually actuated
• CPC Class Codes: B64C 27/68 using electrical energy, e.g. having electrical power amplification
• CPC Class Codes: B64C 27/78 in association with pitch adjustment of blades of anti-torque rotor
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 74/20528 Foot operated
• CPC Class Codes: Y10T 74/20888 Pedals
• CPC Class Codes: Y10T 74/209 Extension

Abstract

A pedal system particularly tailored to a Fly-By-Wire (FBW) flight control system includes a double gradient linkage assembly. The double gradient linkage assembly includes a damper system and a spring system that improves yaw axis (azimuth) control of the aircraft. Control is only required when a change in the yaw axis state is demanded. Since only minimal displacement inputs to such a FBW flight control system is required, the travel of the pedals are exceeding compact, such that pilot workload is significantly reduced through the reduction in the frequency and magnitude of aircraft control inputs.

Claims

1. A pedal system for a rotary-wing aircraft comprising:

a port pedal;

a starboard pedal; and

a double gradient linkage assembly linked to said port pedal and said starboard pedal to provide a double gradient pedal dynamic.

2. The pedal system as recited in claim 1, wherein said port pedal and said starboard pedal are linked to a support structure through a crank assembly, said crank assembly pivotable relative said support structure about a support axis.

3. The pedal system as recited in claim 2, further comprising a pushrod attached between said crank assembly and a main pivot crank of said double gradient linkage assembly, said main pivot crank pivotable about a pivot axis non-parallel to said support axis.

4. The pedal system as recited in claim 3, wherein said pushrod is pivotally mounted to said main pivot crank adjacent an end segment thereof about a pushrod axis.

5. The pedal system as recited in claim 4, further comprising a spring system connected between said main pivot crank and a fixed structure, said spring system pivotally attached to said main pivot crank along said pushrod axis.

6. The pedal system as recited in claim 5, further comprising a damper system connected between said main pivot crank and a fixed structure, said damper system pivotally attached to said main pivot crank at a damper pivot axis longitudinally located between said pivot axis and said pushrod axis.

7. The pedal system as recited in claim 3, further comprising a fly-by-wire input pivotally connected to an end segment of said main pivot crank at an input axis opposite said pushrod axis.

8. The pedal system as recited in claim 7, wherein said fly-by-wire input includes a Rotational Variable Differential Transformer.

9. The pedal system as recited in claim 7, wherein said fly-by-wire input is in communication with a flight control system.

10. The pedal system as recited in claim 1, wherein said double gradient linkage assembly provides a first resistance over a first travel of said port pedal and said starboard pedal and a second resistance over a second travel of said port pedal and said starboard pedal, said first resistance greater than said second resistance.

11. A rotary-wing aircraft comprising:

an anti-torque tail rotor system;

a Fly-By-Wire flight control system in communication with said anti-torque tail rotor system; and

a pedal system in communication with said Fly-By-Wire flight control system to control said anti-torque tail rotor system, said pedal system including a double gradient linkage assembly to provide a double gradient force feedback pedal dynamic.

12. The rotary-wing aircraft as recited in claim 11, wherein said double gradient linkage assembly provides a first resistance over a first travel of said pedal system and a second resistance over a second travel of said pedal system, said first resistance greater than said second resistance.

13. The rotary-wing aircraft as recited in claim 11, wherein said pedal system is in communication with said Fly-By-Wire flight control system through a Rotational Variable Differential Transformer.

17. The rotary-wing aircraft as recited in claim 11, wherein said pedal system includes a port pedal and starboard pedal linked to a support structure through a crank assembly, said crank assembly pivotable relative said support structure about a support axis.

18. The rotary-wing aircraft as recited in claim 17, further comprising a pushrod attached between said crank assembly and a main pivot crank of said double gradient linkage assembly, said main pivot crank pivotable about a pivot axis non-parallel to said support axis.

19. The rotary-wing aircraft as recited in claim 18, wherein said pushrod is pivotally mounted to said main pivot crank adjacent an end segment thereof about a pushrod axis.

20. The rotary-wing aircraft as recited in claim 19, further comprising a spring system connected between said main pivot crank and a fixed structure, said spring system pivotally attached to said main pivot crank along said pushrod axis.

21. The rotary-wing aircraft as recited in claim 20, further comprising a damper system connected between said main pivot crank and a fixed structure, said damper system pivotally attached to said main pivot crank at a damper pivot axis longitudinally located between said pivot axis and said pushrod axis.

22. The rotary-wing aircraft as recited in claim 18, further comprising a fly-by-wire input to said fly-by-wire flight control system, said fly-by-wire input pivotally connected to an end segment of said main pivot crank at an input axis opposite said pushrod axis.

23. The rotary-wing aircraft as recited in claim 11, wherein said double gradient linkage assembly provides a first resistance of approximately 40 lbs. per inch for the first 0.2 inches of said pedal system and a resistance of approximately 20 lbs. per inch over the remainder of the pedal travel.

24. The rotary-wing aircraft as recited in claim 23, wherein a total pedal travel of said pedal system is approximately ±

1.25 inches.

25. The rotary-wing aircraft as recited in claim 11, wherein said pedal system includes a spring system and a damper system to provide said double gradient pedal dynamic.

26. The rotary-wing aircraft as recited in claim 11, wherein said double gradient linkage assembly provides a centering force to said pedal system.

27. The rotary-wing aircraft as recited in claim 12, wherein said first resistance increases in a linear manner for a first travel of said pedal system and said second resistance increases linearly subsequent to said first resistance, said second resistance defining a slope less than a slope defined by said first resistance.

14. A method of controlling a yaw axis of a rotary-wing aircraft comprising the steps of:

(A) maintaining stability and coordination through a fly-by-wire flight control system; and

(B) receiving a pilot yaw control input only when a change in a yaw axis state is demanded, the pilot yaw control input provided through a double gradient pedal dynamic.

15. A method as recited in claim 14, wherein said step (B) further comprises:

(a) providing the double gradient pedal dynamic through a pedal system having a compact travel.

16. A method as recited in claim 14, wherein said step (B) further comprises:

(a) providing a first resistance for a first travel of the pilot yaw control input; and

(b) providing a second resistance less than the first resistance for travel of the pilot yaw control input beyond the first travel.