Automatic heading control system for tiltrotor aircraft and helicopters

• US 7,617,024 B2
• Filed: 09/22/2006
• Issued: 11/10/2009
• Est. Priority Date: 09/22/2006
• Status: Active Grant

• Current Assignee: Textron Innovations Incorporated (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: Builta, Kenneth E.
• Primary Examiner(s): Tran; Dalena
• Application Number:
  US11/524,888
• Publication Number:
  US 20080075591A1
• Time in Patent Office: 1,145 Days
• Field of Search: 701/2, 701/7, 701/10, 701/200, 701/206, 701/201, 701/210, 731/78.R, 244/17.11, 244/17.13, 244/17.19, 244/195, 244/197, 702/144
• US Class Current: 701/10
• CPC Class Codes: G05D 1/0202 specially adapted to aircraft

Abstract

One embodiment of the present invention is a method for automatically reducing the effect of a component of an external force that is laterally incident on a rotorcraft. A signal of the rotorcraft indicative of and proportional to the component is monitored. An absolute value of the signal and a preset high limit are compared. If the absolute value is greater than the preset high limit, manual heading control of the rotorcraft is disabled and the heading of the rotorcraft is adjusted with respect to the external force so as to decrease the lateral component of the external force experienced by the rotorcraft.

Claims

1. A method for automatically reducing the effect of a component of an external force that is laterally incident on a rotorcraft, comprising:

monitoring a signal of the rotorcraft indicative of and proportional to the component;

comparing an absolute value of the signal and a preset high limit of the signal; and

if the absolute value is greater than the preset high limit, disabling manual heading control of the rotorcraft and adjusting the heading of the rotorcraft with respect to the external force so as to decrease the component.

2. The method of claim 1, wherein the external force comprises a cross wind.

3. The method of claim 1, further comprising if the absolute value is less than a preset low limit of the signal, enabling manual control of the rotorcraft.

4. The method of claim 1, wherein adjusting the heading of the rotorcraft with respect to the external force so as to decrease the component comprises calculating a heading error from a difference between the signal and a current heading of the rotorcraft and providing the heading error to a flight control system of the rotorcraft to control the heading of the rotorcraft.

5. A method for automatically reducing the effect of a component of an external force that is laterally incident on a rotorcraft, comprising:

monitoring a signal of the rotorcraft indicative of and proportional to the component;

comparing an absolute value of the signal and a preset high limit of the signal; and

if the absolute value is greater than the preset high limit, disabling manual heading control of the rotorcraft and adjusting the heading of the rotorcraft with respect to the external force so as to decrease the component, wherein the signal is one of a lateral swashplate position signal and a lateral acceleration signal.

6. A method for automatically controlling the heading of a rotorcraft, comprising:

monitoring a lateral control signal of the rotorcraft;

comparing an absolute value of the lateral control signal to a preset high limit of the signal; and

if the absolute value is greater than to the preset high limit;

(a) calculating a lateral heading command from the lateral control signal that will decrease the absolute value,

(b) calculating a heading error from a difference between the lateral heading command and a current heading of the rotorcraft,

(c) disabling a manual heading command, and

(d) providing the heading error to a flight control system of the rotorcraft to control the heading of the rotorcraft.

7. The method of claim 6, wherein the lateral control signal is one of a lateral swashplate position signal and a lateral acceleration signal.

8. The method of claim 7, wherein the lateral swashplate position signal comprises an angle.

9. The method of claim 7, wherein the lateral acceleration signal comprises an acceleration.

10. The method of claim 6, further comprising:

if the absolute value is less than a preset low limit of the signal,

enabling manual heading command,

calculating a manual heading error from a difference between the manual heading

command and a current heading of the rotorcraft, and

providing the manual heading error to a flight control system of the rotorcraft to control the heading of the rotorcraft.

11. The method of claim 6, wherein calculating a lateral heading command from the lateral control signal that will decrease the absolute value comprises

entering the lateral control signal in a lookup table and

receiving the lateral heading command from the lookup table.

12. The method of claim 6, wherein the rotorcraft is one of a manned vehicle and an unmanned vehicle.

13. A system for automatically controlling the heading of a rotorcraft, comprising:

a data capture module for monitoring a lateral control signal of the rotorcraft;

a comparison module that accepts the lateral control signal as input from the data capture module and compares an absolute value of the lateral control signal to a preset high limit of the signal; and

a heading control module that

accepts the lateral control signal as input from the data capture module and a result of the comparison of the absolute value of the lateral control signal to a preset high limit as input from the comparison module,

calculates a lateral heading command from the lateral control signal that will decrease the absolute value,

calculates a heading error from a difference between the lateral heading command and a current heading of the rotorcraft,

disables a manual heading command, and

provides the heading error to a flight control system of the rotorcraft to control the heading of the rotorcraft, if the result identifies the absolute value as greater than the preset high limit.

14. The system of claim 13, wherein the lateral control signal is one of a lateral swashplate position signal and a lateral acceleration signal.

15. The system of claim 14, wherein the lateral swashplate position signal comprises an angle.

16. The system of claim 14, wherein the lateral acceleration signal comprises an acceleration.

17. The system of claim 13, wherein the heading control module

enables manual heading command,

calculates a manual heading error from a difference between the manual heading command and a current heading of the rotorcraft, and

provides the manual heading error to a flight control system of the rotorcraft to control the heading of the rotorcraft, if the absolute value is less than a preset low limit of the signal.

18. The system of claim 13, wherein the heading control module calculates a lateral heading command from the lateral control signal that will decrease the absolute value by entering the lateral control signal in a lookup table and receiving the lateral heading command from the lookup table.

19. The system of claim 13, wherein the rotorcraft is one of a manned vehicle and an unmanned vehicle.

20. The system of claim 13, wherein the comparison module uses an average value of the lateral control signal over time.

21. The system of claim 13, wherein the heading control module limits the lateral heading command between a high and a low value and limits the rate of change of the lateral heading command.