Envelope protection for mechanically-controlled aircraft

• US 8,195,346 B1
• Filed: 01/21/2009
• Issued: 06/05/2012
• Est. Priority Date: 01/21/2009
• Status: Active Grant

• Current Assignee: Garmin International, Inc. (Garmin Limited)
• Original Assignee: Garmin International, Inc. (Garmin Limited)
• Inventors: Duerksen, Noel J., Johnson, John C., Williams, Justin S.
• Primary Examiner(s): Beaulieu, Yonel
• Application Number:
  US12/356,936
• Time in Patent Office: 1,231 Days
• Field of Search: 701/3, 701 13- 15, 244/75.R, 244/158.R
• US Class Current: 701/15
• CPC Class Codes: B64C 13/16 actuated automatically, e.g. responsive to gust detectors
• CPC Class Codes: B64C 13/28 mechanical

Abstract

An avionics system for a mechanically-controlled aircraft configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for flight parameters such as banking angle, pitch attitude, g loading, proximity to terrain and/or obstacles, angle of attack, and/or airspeed. The avionics system may comprise at least one servo actuator and a computing device. The computing device may engage envelope protection by engaging the at least one servo actuator if the aircraft reaches a maximum or minimum limit for any of the flight parameters, such that the at least one servo actuator provides a force to urge a flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits. The servo actuator may be disengaged when the aircraft flight parameters reach an end value corresponding to the start value that triggered envelope protection to engage.

Claims

1. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged;

a computing device configured to—

receive flight parameters from one or more sensors, and

engage envelope protection by engaging the at least one servo actuator if one or more of the flight parameters received reach or exceed any of the acceptable flight parameter limits, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits; and

an autopilot system communicably connected or integral with the computing device, such that availability of envelope protection is dependent on the status of the autopilot system.

2. The avionics system of claim 1, wherein the at least one servo actuator gradually ramps up to a full force when engaged.

3. The avionics system of claim 1, wherein the computing device is configured to disengage the at least one servo actuator if a force is provided by the pilot to the flight control device for a predetermined length of time in a direction opposite of the force provided by the servo actuator.

4. The avionics system of claim 1, wherein the computing device is further configured to disengage the at least one servo actuator once at least one of the flight parameters reaches an end value that is within the acceptable flight parameter limits.

5. The avionics system of claim 4, wherein the computing device is configured to disengage the at least one servo actuator prior to the aircraft reaching the start value if the control device is being moved toward the start value by the pilot at a faster rate than the servo actuator for a predetermined length of time.

6. The avionics system of claim 1, wherein the flight parameters comprise banking angles, pitch attitude, g loading, proximity to terrain or obstacles, angle of attack, or airspeed.

7. The avionics system of claim 6, wherein the computing device is configured to instruct the at least one servo actuator to urge the control device in a direction toward acceptable airspeed limits if both pitch attitude and airspeed are outside of acceptable flight parameter limits.

8. The avionics system of claim 6, wherein the computing device is configured to change a force characteristic of the servo actuator if the airspeed falls below a predetermined minimum limit to alert the pilot.

9. The avionics system of claim 1, wherein the autopilot is configured to engage if the pilot has applied no force to the control device for a predetermined amount of time or the envelope protection has remained engaged for a particular percentage of time within a predetermined length of time.

10. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for any one of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged; and

a computing device configured to;

receive data from one or more sensors regarding any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, and airspeed of the aircraft, and

engage envelope protection by engaging the at least one servo actuator if any of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack and airspeed reach or exceed their corresponding acceptable flight parameter limits, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits;

wherein the computing device stores or calculates a maximum and a minimum start value and a maximum and a minimum end value for any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, wherein the maximum and minimum start values are equal to the acceptable flight parameter limits and the corresponding maximum and minimum end values are between maximum and minimum acceptable flight parameter limits, such that the at least one servo actuator is engaged when any of the start values are reached and is disengaged when the corresponding end value is reached.

11. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for any one of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged; and

a computing device configured to;

receive data from one or more sensors regarding any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, and airspeed of the aircraft, and

engage envelope protection by engaging the at least one servo actuator if any of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack and airspeed reach or exceed their corresponding acceptable flight parameter limits, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits;

wherein the at least one servo actuator gradually ramps up to a full force when engaged.

12. The avionics system of claim 11, wherein the at least one servo actuator applies a variable force based on one or more of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, and airspeed of the aircraft.

13. The avionics system of claim 11, wherein the computing device is configured to instruct the at least one servo actuator to urge the control device in a direction toward acceptable airspeed limits if both pitch attitude and airspeed are outside of the acceptable flight parameter limits.

16. The avionics system of claim 11, wherein the computing device is configured to change a force characteristic of the servo actuator if the airspeed falls below a predetermined minimum limit to alert the pilot.

14. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for any one of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged; and

a computing device configured to;

receive data from one or more sensors regarding any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, and airspeed of the aircraft, and

engage envelope protection by engaging the at least one servo actuator if any of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack and airspeed reach or exceed their corresponding acceptable flight parameter limits, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits;

wherein the computing device is configured to disengage the at least one servo actuator if a sufficient force is provided by the pilot to the control device for a sufficient length of time in a direction opposite of the force provided by the servo actuator.

15. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for any one of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged; and

a computing device configured to;

receive data from one or more sensors regarding any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, and airspeed of the aircraft, and

engage envelope protection by engaging the at least one servo actuator if any of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack and airspeed reach or exceed their corresponding acceptable flight parameter limits, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits;

wherein the computing device is configured to disengage the at least one servo actuator if the control device is being moved toward a desired end value by the pilot at a faster rate than the servo actuator for a certain length of time.

17. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for any one of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged; and

a computing device configured to;

receive data from one or more sensors regarding any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, and airspeed of the aircraft, and

engage envelope protection by engaging the at least one servo actuator if any of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack and airspeed reach or exceed their corresponding acceptable flight parameter limits, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits; and

an autopilot system communicably connected or integral with the computing device, such that availability of envelope protection is dependent on the status of the autopilot system, wherein the autopilot is configured to engage if the pilot has applied no force to the control device for a predetermined amount of time or the envelope protection has remained engaged for a particular percentage of time within a predetermined length of time.

18. An avionics system for a mechanically-controlled aircraft having a flight control device, the avionics system configured to provide envelope protection for deterring a pilot from flying outside of acceptable flight parameter limits for any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, the avionics system comprising:

at least one servo actuator connected with the flight control device of the aircraft such that the servo actuator provides force to the flight control device when engaged, wherein the at least one servo actuator is operable to gradually ramp up to a full torque when engaged;

a computing device having a memory and configured to;

receive data from one or more sensors regarding any of banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed readings of the aircraft,

store or calculate a maximum and a minimum start value and a maximum and a minimum end value for any of pitch angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed, wherein the maximum and minimum start values are equal to the acceptable flight parameter limits and the corresponding maximum and minimum end values are between maximum and minimum acceptable flight parameter limits,

engage envelope protection by engaging the at least one servo actuator if the maximum or minimum start value for any of the banking angle, pitch attitude, g loading, proximity to at least one of terrain and obstacles, angle of attack, and airspeed are reached or exceeded, such that the at least one servo actuator provides a force to urge the flight control device in a direction to bring the aircraft back within the acceptable flight parameter limits, and

disengage envelope protection by disengaging the at least one servo actuator if the aircraft reaches the end value corresponding to the start value that triggered envelope protection to engage; and

an autopilot system communicably connected or integral with the computing device, such that envelope protection is operable to be engaged only when autopilot is available but not engaged.

19. The avionics system of claim 18, wherein a maximum start pitch at which envelope protection is engaged is the lowest of:

a calculated pitch attitude required to capture and hold a minimum airspeed,

a calculated pitch attitude required to maintain a minimum g loading,

a calculated pitch attitude required to maintain a minimum angle of attack, and

a maximum pitch attitude stored in the memory of the computing device.

20. The avionics system of claim 18, wherein a minimum start pitch at which envelope protection is engaged is the highest of:

a calculated pitch attitude required to capture and hold the maximum airspeed,

a calculated pitch attitude required to maintain a maximum g loading, and

a minimum pitch attitude stored in the memory of the computing device.

21. The avionics system of claim 18, further including a display coupled with the computing device, the display operable to present an indication of the availability of envelope protection, wherein the display of the availability of envelope protection is independent of the ability of the computing device to engage envelope protection.