Method and apparatus for tracking center of gravity of air vehicle

• US 8,260,477 B2
• Filed: 12/04/2007
• Issued: 09/04/2012
• Est. Priority Date: 12/04/2007
• Status: Expired due to Fees

• Current Assignee: King FAHD University of Petroleum & Minerals Research & Innovation Support Office
• Original Assignee: King Fahd University Of Petroleum And Minerals
• Inventors: Almalki, Mohammad F., Elshafei, Moustafa
• Primary Examiner(s): Nguyen, John
• Assistant Examiner(s): KIM, KYUNG J
• Application Number:
  US11/987,797
• Publication Number:
  US 20090143926A1
• Time in Patent Office: 1,736 Days
• Field of Search: 701/3, 73/10.1, 73/650.5, 73/650.6, 73/650.7, 735/040.3, 735/040.2, 735/140.1, 735/10, 735/11, 738/02, 731/700.2
• US Class Current: 701/3
• CPC Class Codes: G01C 21/185 for gravity
• CPC Class Codes: G01M 1/127 during the flight

Abstract

The method and apparatus for tracking a center of gravity (COG) of an air vehicle provides a precise calculation and updating of the COG by disposing a plurality of acceleration measuring devices on a circumference of one or more rings in a manner that establishes redundancy in acceleration measurement. A multivariable time-space adaptive technique is provided within a high speed digital signal processor (DSP) to calculate and update the position of the COG. The system provides the capability of executing a procedure that reduces dispersion in estimating angular velocities and lateral accelerations of a moving vehicle and corrects the vehicle'"'"'s estimated angular velocities and lateral accelerations. In addition, a consistency check of the measured values from the acceleration measuring devices is performed to assist in fault detection and isolation of a faulty accelerometer in the system.

Claims

1. An apparatus for tracking a center of gravity of an air vehicle, comprising:

a primary set of sensor assemblies oriented for dynamically measuring at least one flight parameter and generating primary signals corresponding thereto, the primary set being adapted for measuring the flight parameter along three mutually orthogonal axes of an aircraft;

a redundant set of sensor assemblies oriented for dynamically measuring the same flight parameter as the primary set of sensor assemblies and generating redundant signals corresponding thereto, the redundant set being adapted for measuring the flight parameter along the same three mutually orthogonal axes of the aircraft as the primary set of sensor assemblies;

a signal processor connected to the primary and redundant sensor assemblies, the signal processor having;

signal sampling means for sampling the primary and redundant signals from the sensor assemblies at predetermined time intervals;

center of gravity processing means for forming a primary estimate of the center of gravity of the aircraft from the primary signals, means for forming at least one redundant estimate of the center of gravity from the redundant signals, and means for filtering out unreliable sensor signals and combining the primary and at least one redundant estimates to obtain a corrected estimate of the center of gravity at the predetermined time intervals;

guidance and control parameter processing means for dynamically calculating guidance and control parameters from the corrected center of gravity at the predetermined time intervals; and

means for high speed communication of the calculated guidance and control parameters to a flight guidance and control processor;

wherein said center of gravity processing means for forming said primary or redundant estimate comprises;

means for solving angular rate of change state equations, including;

2. The apparatus for tracking a center of gravity according to claim 1, wherein said at least one annular ring comprises a first annular ring and a second annular ring, the first and second annular rings being adapted for mounting in fore and aft positions in the aircraft, respectively, said primary set of sensor assemblies being mounted on one of the annular rings, the first and second annular rings having said at least one redundant set of sensor assemblies mounted thereon.

3. The apparatus for tracking a center of gravity according to claim 1, wherein said center of gravity processing means implements a time-space adaptive algorithm.

4. The apparatus for tracking a center of gravity according to claim 1, wherein said center of gravity processing means implements decision trees or fuzzy logic for determining faulty and unreliable sensor signals and combining the primary and at least one redundant estimates to obtain the corrected estimate of the center of gravity at the predetermined time intervals.

5. The apparatus for tracking a center of gravity according to claim 1, wherein each said sensor assembly comprises of three mutually orthogonal accelerometers.

6. The apparatus for tracking a center of gravity according to claim 1, wherein said means for filtering out unreliable sensor signals and combining the primary and at least one redundant estimates comprises a stochastic filter incorporating all redundant measurements from all of said sensor assemblies.

7. The apparatus for tracking a center of gravity according to claim 1, wherein said means for filtering out unreliable sensor signals and combining the primary and at least one redundant estimates comprises means for estimating angular velocities using a stochastic filter to obtain a first level estimate of angular velocities, COG position and body accelerations.

8. The apparatus for tracking a center of gravity according to claim 1, further comprising means for identifying and isolating a defective sensor among the primary and at least one redundant sensor assemblies.

9. A method for tracking a flight vehicle'"'"'s center of gravity during flight, comprising the steps of:

mounting a primary set of sensor assemblies in the flight vehicle in an orientation for dynamically measuring at least one flight parameter and generating primary signals corresponding thereto, the primary set being adapted for measuring the flight parameter along three mutually orthogonal axes of an aircraft;

mounting a redundant set of sensor assemblies in the flight vehicle in an orientation for dynamically measuring the same flight parameter as the primary set of sensor assemblies and generating redundant signals corresponding thereto, the redundant set being adapted for measuring the flight parameter along the same three mutually orthogonal axes of the aircraft as the primary set of sensor assemblies;

sampling the primary and redundant signals from the sensor assemblies with a signal processor at predetermined time intervals;

forming a primary estimate of the center of gravity of the aircraft from the primary signals;

forming at least one redundant estimate of the center of gravity from the redundant signals;

filtering out unreliable sensor signals;

combining the primary and at least one redundant estimates to obtain a corrected estimate of the center of gravity at the predetermined time intervals; and

dynamically calculating guidance and control parameters from the corrected center of gravity at the predetermined time intervals;

wherein said step of forming the primary estimate of the center of gravity comprises the steps of;

solving angular rate of change state equations, including;

10. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, further comprising the step of communicating the calculated guidance and control parameters to a flight guidance and control processor using high speed communications.

11. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, wherein said steps of mounting the primary and at least one redundant sets of sensor assemblies further comprise the steps of:

mounting first and second annular ring annular rings at fore and aft positions, respectively, in the flight vehicle;

mounting said primary set of sensor assemblies on one of the annular rings; and

mounting said at least one redundant set of sensor assemblies on said first and second annular rings.

12. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, wherein said steps of filtering out unreliable sensor signals and combining the primary and at least one redundant estimates further comprise implementing a time-space adaptive algorithm.

13. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, wherein said steps of filtering out unreliable sensor signals and combining the primary and at least one redundant estimates further comprise implementing fuzzy logic to obtain the corrected estimate of the center of gravity at the predetermined time intervals.

14. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, further comprising the step of using a stochastic filter to incorporate all redundant measurements from all of said sensor assemblies.

15. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, further comprising the step of estimating angular velocities using a stochastic filter to obtain a first level estimate of angular velocities, COG position and body accelerations.

16. The method for tracking a flight vehicle'"'"'s center of gravity according to claim 9, further comprising the step of identifying and isolating a defective sensor among the primary and at least one redundant sensor assemblies.