Aircraft weight estimation

Patent metadata

Field	Value
Publication number	US-10006801-B2
Application number	US-201715407903-A
Country	US
Kind code	B2
Filing date	Jan 17, 2017
Priority date	Mar 31, 2016
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

In an embodiment, a method for aircraft weight estimation is provided that includes determining a weight signal based on a dynamic pressure signal, a calibrated angle of attack signal, a lift coefficient signal, a load factor signal, and a wing surface area. In another embodiment, a method to estimate aircraft weight is provided that includes determining a weight based on historical flight data relating horizontal control surface position to dynamic pressure. In another embodiment, a system for continuously estimating aircraft weight during flight is provided that includes a pitot-static subsystem, an angle of attack indicator, an accelerometer, a controller configured to provide a weight signal, and a signal filter for filtering the weight signal to determine a stable aircraft weight.

First claim

The invention claimed is:

1. A method for aircraft weight estimation, comprising:
providing a dynamic pressure signal from a pitot-static subsystem;
determining a calibrated angle of attack signal from an angle of attack indicator;
determining a lift coefficient signal based on the calibrated angle of attack signal and a Mach number;
providing a load factor signal from an accelerometer; and
determining a weight signal based on the dynamic pressure signal, the calibrated angle of attack signal, the lift coefficient signal, the load factor signal, and a wing surface area.

2. The method of claim 1 , wherein determining the lift coefficient is further based on a flap position.

3. The method of claim 1 , further comprising determining a time-averaged weight signal by averaging the weight signal over time.

4. The method of claim 1 , further comprising updating the lift coefficient based on one or more lookup tables.

5. A method for aircraft weight estimation, comprising:
measuring a horizontal control surface position with a sensor;
providing a dynamic pressure from a pitot-static subsystem;
determining a weight using historical flight data relating the horizontal control surface position to the dynamic pressure based on aircraft weight; and
repeating continuously during flight the steps of measuring the horizontal control surface position, providing the dynamic pressure, and determining the weight to provide a weight signal.

6. The method of claim 5 , further comprising filtering the weight signal by averaging the weight over time.

7. The method of claim 5 , further comprising determining an airspeed based on the dynamic pressure signal.

8. The method of claim 7 , further comprising determining a Mach number based on the airspeed and a temperature measured with a temperature sensing device.

9. The method of claim 8 , further comprising updating the weight based on the Mach number and an air density measured using the pitot-static subsystem.

10. The method of claim 9 , further comprising determining a center of gravity based on the weight signal and an amount of fuel onboard the aircraft.

11. The method of claim 10 , further comprising updating the weight signal based on the center of gravity.

12. A system for continuously estimating aircraft weight during flight, comprising:
a pitot-static subsystem for providing a dynamic pressure signal;
an angle of attack indicator for providing a calibrated angle of attack signal;
an accelerometer for providing a load factor signal;
a controller configured to provide a weight signal based on an initial weight, the dynamic pressure signal, the calibrated angle of attack signal, and the load factor signal; and
a signal filter for filtering the weight signal to determine a stable aircraft weight.

13. The system of claim 12 , further comprising a flap indicator to sense a flap position for updating the lift coefficient.

14. The system of claim 12 , further comprising a lift-coefficient-slope lookup table for determining the lift coefficient based on the calibrated angle of attack signal.

15. The system of claim 12 , further comprising an airspeed indicator for providing airspeed based on the dynamic pressure signal.

16. The system of claim 15 , further comprising a zero-degree angle-of-attack lift coefficient lookup table for determining the lift coefficient based on airspeed.

17. The system of claim 12 , further comprising a control surface sensor for sensing a control surface position and a trim table based on historical flight data relating the control surface position to the dynamic pressure signal for a range of weights.

Assignees

• Cessna Aircraft Co
• Textron Innovations Inc

Inventors

• Hagerott Steven G
• Peters Russell

Classifications

• G01P13/025

  indicating air data, i.e. flight variables of an aircraft, e.g. angle of attack, side slip, shear, yaw · CPC title

• G01G19/07 Primary

  for weighing aircraft · CPC title

• B64F5/60

  Testing or inspecting aircraft components or systems · CPC title

• G01P15/00

  Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration · CPC title

• G01P5/16

  using Pitot tubes {, e.g. Machmeter} · CPC title