TRAJECTORY TRACKING FLIGHT CONTROLLER

• US 20120095621A1
• Filed: 03/25/2010
• Published: 04/19/2012
• Est. Priority Date: 03/26/2009
• Status: Active Grant

• Current Assignee: Ohio University
• Original Assignee: Ohio University
• Inventors: Zhu, Jianchao, Adami, Tony M.
• Granted Patent: US 8,761,966 B2
• Time in Patent Office: Days
• US Class Current: 701/3
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G05D 1/08 Control of attitude, i.e. control of roll, pitch, or yaw
• CPC Class Codes: G05D 1/0808 specially adapted for aircraft
• CPC Class Codes: G05D 1/0825 using mathematical models
• CPC Class Codes: G05D 1/085 to ensure coordination between different movements
• CPC Class Codes: G05D 1/101 specially adapted for aircraft

Abstract

A six degree-of-freedom trajectory linearization controller (TLC) architecture (30) for a fixed-wing aircraft (46) is set forth. The TLC architecture (30) calculates nominal force and moment commands by dynamic inversion of the nonlinear equations of motion. A linear time-varying (LTV) tracking error regulator provides exponential stability of the tracking error dynamics and robustness to model uncertainty and error. The basic control loop includes a closed-loop, LTV stabilizing controller (12), a pseudo-inverse plant model (14), and a nonlinear plant model(16). Four of the basic control loops (34, 36, 40, 42) are nested to form the TLC architecture (30).

Claims

1. An apparatus, comprising:

a trajectory planner adapted to produce a command position vector for a fixed-wing aircraft;

a TLC architecture electrically coupled to the trajectory planner to receive the command position vector from the trajectory planner;

an avionic sensor electrically couple to the TLC architecture to send a sensed parameter to the TLC architecture; and

a control actuator electronically coupled to the TLC architecture to receive a control signal from the TLC architecture;

wherein the TLC architecture includes;

a processor; and

program code configured to execute on the processor to generate the control signal by;

determining in a first control loop a nominal body velocity vector and a feedback control body velocity command vector using the command position vector from the trajectory planner;

determining in a second control loop a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop;

determining in a third control loop a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop;

determining in a fourth control loop a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and

determining the control signal using the moment command vector from the fourth control loop.

2. The apparatus of claim 1 wherein determining in the first control loop the feedback control body velocity command vector further uses a sensed position vector from the avionic sensor.

3. The apparatus of claim 1 wherein determining in the second control loop the feedback control Euler angle command vector and the throttle setting feedback control command further uses a sensed velocity vector from the avionic sensor.

4. The apparatus of claim 1 wherein determining in the third control loop the nominal body rate vector and the feedback control body rate command vector further uses a sensed Euler angle vector from the avionic sensor.

5. The apparatus of claim 1 wherein determining in the fourth control loop the moment command vector further uses a sensed body rate vector from the avionic sensor.

6. The apparatus of claim 1 wherein the sensed parameter from the avionic sensor includes a sensed position vector, a sensed velocity vector, a sensed Euler angle vector, and a sensed body rate vector.

7. The apparatus of claim 1 wherein determining in the first control loop the feedback control body velocity command vector further uses a sensed position vector from the avionic sensor, determining in the second control loop the feedback control Euler angle command vector and the throttle setting feedback control command further uses a sensed velocity vector from the avionic sensor, determining in the third control loop the nominal body rate vector and the feedback control body rate command vector further uses a sensed Euler angle vector from the avionic sensor, determining in the fourth control loop the moment command vector further uses a sensed body rate vector from the avionic sensor.

8. The apparatus of claim 1 wherein the control signal includes an engine throttle, aileron, elevator, rudder, or flaperon deflection command.

9. The apparatus of claim further comprising:

an aircraft having an airframe and a control effector, the control effector being adapted to receive the control signal from the control actuator.

10. The apparatus of claim 9 wherein the control effector is an engine throttle, aileron, elevator, rudder, or flaperon.

11. A method of generating a control signal, the method comprising:

determining using a hardware implemented processor in a first control loop a nominal body velocity vector and a feedback control body velocity command vector using a command position vector for a fixed-wing aircraft from a trajectory planner;

determining using the processor in a second control loop a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop;

determining using the processor in a third control loop a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop;

determining using the processor in a fourth control loop a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and

determining using the processor a control signal using the moment command vector from the fourth control loop.

12. The method of claim 11 wherein determining in the first control loop the feedback control body velocity command vector further uses a sensed position vector from an avionic sensor.

13. The method of claim 11 wherein determining in the second control loop the feedback control Euler angle command vector and the throttle setting feedback control command further uses a sensed velocity vector from an avionic sensor.

14. The method of claim 11 wherein determining in the third control loop the nominal body rate vector and the feedback control body rate command vector further uses a sensed Euler angle vector from an avionic sensor.

15. The method of claim 11 wherein determining in the fourth control loop the moment command vector further uses a sensed body rate vector from an avionic sensor.

16. The method of claim 11 wherein determining in the first control loop the feedback control body velocity command vector further uses a sensed position vector from an avionic sensor, determining in the second control loop the feedback control Euler angle command vector and the throttle setting feedback control command further uses a sensed velocity vector from the avionic sensor, determining in the third control loop the nominal body rate vector and the feedback control body rate command vector further uses a sensed Euler angle vector from the avionic sensor, determining in the fourth control loop the moment command vector further uses a sensed body rate vector from the avionic sensor.

17. The method of claim 11 further comprising:

sending the control signal to a control actuator, the control actuator being coupled to a control effector.

18. The method of claim 17 wherein the control effector is an engine throttle, aileron, elevator, rudder, or flaperon.

19. The method of claim 18 wherein the control signal includes an engine throttle, aileron, elevator, rudder, or flaperon deflection command.

20. A program product, comprising:

a computer readable medium; and

program code stored on the computer readable medium, the program code configured to execute on a hardware implemented processor to generate a control signal by;

determining in a first control loop a nominal body velocity vector and a feedback control body velocity command vector using the command position vector from a trajectory planner;

determining in a second control loop a nominal Euler angle vector, a feedback control Euler angle command vector, and a throttle setting feedback control command using the nominal body velocity vector and the feedback control body velocity command vector from the first control loop;

determining in a third control loop a nominal body rate vector and a feedback control body rate command vector using the nominal Euler angle vector and the feedback control Euler angle command vector from the second control loop;

determining in a fourth control loop a moment command vector using the nominal body rate vector and the feedback control body rate command vector from the third control loop; and

determining the control signal using the moment command vector from the fourth control loop.