LOSS-OF-CONTROL PREVENTION AND RECOVERY FLIGHT CONTROLLER

• US 20180267560A1
• Filed: 03/21/2018
• Published: 09/20/2018
• Est. Priority Date: 09/22/2015
• Status: Active Grant

• Current Assignee: Ohio University
• Original Assignee: Ohio University
• Inventors: Zhu, Jianchao, Zhao, Yue
• Granted Patent: US 11,360,491 B2
• Time in Patent Office: Days
• CPC Class Codes: B64C 13/16 actuated automatically, e.g. responsive to gust detectors
• CPC Class Codes: B64C 19/00 Aircraft control not otherwise provided for
• CPC Class Codes: G05D 1/0072 to counteract a motor failure
• CPC Class Codes: G05D 1/042 specially adapted for aircraft
• CPC Class Codes: G05D 1/0808 specially adapted for aircraft
• CPC Class Codes: G05D 1/0816 to ensure stability
• CPC Class Codes: G05D 1/101 specially adapted for aircraft

Abstract

A loss-of-control prevention and recovery automatic control system of an aircraft is provided having a plurality of flight control mode, including a nominal flight control mode, a loss-of-control prevention control mode, a loss-of-control arrest control mode, and a nominal flight restoration control mode, as well as a supervisory control system capable of monitoring the flight states and flight events of the aircraft and determining which flight control mode to activate.

Claims

1. A multi-modal control system for a fixed-wing aircraft, the control system comprising:

one or more processors; and

a memory coupled to the one or more processors and including program code that, when executed by the one or more processors, causes the control system to;

monitor a plurality of flight conditions of the aircraft;

activate one of a plurality of flight control modes based on the flight conditions; and

control the aircraft using the activated flight control mode.

2. The control system of claim 1 wherein the flight control modes include a nominal flight control mode, a loss-of-control prevention control mode, a loss-of-control arrest control mode, and a nominal flight restoration control mode.

3. The control system of claim 2, wherein the nominal flight control mode is defined by a six degree-of-freedom trajectory tracking controller with a wind-triangle and post-stall aerodynamic characteristics in a calculation of the aerodynamic forces, and time-varying parallel differential eigenvalues are implemented in feedback control gain matrices in accordance with equations (9)-(11).

4. The control system of claim 3, wherein the loss-of-control prevention control mode augments the six degree-of-freedom trajectory tracking controller in the nominal flight control mode via gain matrices in accordance with equations (9)-(11).

5. The control system of claim 2, wherein the loss-of-control prevention control mode includes a bandwidth adaptation to the nominal flight control mode to prevent a loss of control of the aircraft.

6. The control system of claim 2, wherein the loss-of-control prevention control mode employs time-varying parallel differential eigenvalues to sacrifice tracking performance to increase a tolerance for severe wind and other abnormalities in real-time.

7. The control system of claim 2, wherein the loss-of-control arrest control mode includes a full throttle control during an arrest phase.

8. The control system of claim 2, wherein the loss-of-control arrest control mode includes a commanded aerodynamic attitude determined by a level and straight flight trim value of angle-of-attack and zero sideslip and bank angles.

9. The control system of claim 8, wherein the loss-of-control arrest control mode tracks the commanded aerodynamic attitude via inner and outer aerodynamic attitude loops.

10. The control system of claim 2, wherein the nominal flight restoration control mode includes a close-in sub-mode for guiding the aircraft to catch up with a target position dictated by a mission trajectory and a home-in sub-mode for restoring the mission trajectory of the aircraft.

11. The control system of claim 10, wherein the close-in sub-mode is defined by a guidance approach wherein a velocity vector of the aircraft is aligned to a line-of-sight vector of the aircraft using proportional-integral-derivative linear regulation in an Earth reference frame.

12. The control system of claim 10, wherein the home-in sub-mode includes a bandwidth adaptation for gradually regaining tracking performance of the aircraft and restoring the mission trajectory of the aircraft.

13. The control system of claim 1 wherein the program code further causes the control system to:

set a value of a supervisory control logic variable according to the flight conditions of the aircraft; and

determine which flight control mode to activate based at least in part on the supervisory control logic variable.

14. The control system of claim 13, wherein the supervisory control logic variable is set to the value corresponding to a respective control mode in response to each flight condition of a set of flight conditions corresponding to the respective control mode being within a respective threshold of a set of thresholds corresponding to the respective control mode.

15. The control system of claim 14, wherein:

the supervisory control logic variable is set to the value corresponding to a nominal flight control mode in response to each flight condition of a corresponding set of flight conditions being within the respective threshold of a set of operation thresholds corresponding to the nominal flight control mode;

the supervisory control logic variable is set to the value corresponding to a loss-of-control prevention control mode in response to each flight condition of the corresponding set of flight conditions being within the respective threshold of a set of protection thresholds corresponding to the loss-of-control prevention control mode;

the supervisory control logic variable is set to the value corresponding to a loss-of-control arrest control mode in response to each flight condition of the corresponding set of flight conditions being within a respective safety threshold of a set of safety thresholds corresponding to the loss-of-control arrest control mode; and

the supervisory control logic variable is set to the value corresponding to a nominal flight restoration control mode in response to each flight condition of the corresponding set of flight conditions being within a respective operation threshold of the set of operation thresholds corresponding to the nominal flight restoration control mode.

16. The control system of claim 14, wherein the supervisory control logic variable is set to the value corresponding to the nominal flight restoration control mode when the predetermined set of flight conditions are each within a predetermined set of operation thresholds and a position error between the aircraft and a target position exceeds a range threshold.

17. A method of controlling a fixed-wing aircraft having an automatic control system, the method comprising:

monitoring a plurality of flight conditions of the aircraft;

activating one of a plurality of flight control modes based on the flight conditions; and

controlling the aircraft using the activated flight control mode.

18. The method of claim 17 wherein the flight control modes include a nominal flight control mode, a loss-of-control prevention control mode, a loss-of-control arrest control mode, and a nominal flight restoration control mode.

19. The method of claim 17 wherein activating one of the plurality of flight control modes based on the flight conditions comprises:

activating a respective control mode in response to each flight condition of a set of flight conditions corresponding to the respective control mode being within a respective threshold of a set of thresholds corresponding to the respective control mode.

20. A computer program product comprising:

a non-transitory computer-readable storage medium; and

program code stored on the non-transitory computer-readable storage medium that, when executed by one or more processors, causes the one or more processors to;

monitor a plurality of flight conditions of the aircraft;

activate one of a plurality of flight control modes based on the flight conditions; and

control the aircraft using the activated flight control mode.