Method and apparatus for determining the mass of a body

• US 10,082,420 B2
• Filed: 08/04/2014
• Issued: 09/25/2018
• Est. Priority Date: 08/06/2013
• Status: Active Grant

• Current Assignee: DGA Precision Ltd.
• Original Assignee: Lacsop Limited
• Inventors: Morris, Gordon A.
• Primary Examiner(s): BOLDUC, DAVID J
• Application Number:
  US14/910,376
• Publication Number:
  US 20160187184A1
• Time in Patent Office: 1,513 Days
• CPC Class Codes: G01G 19/07 for weighing aircraft
• CPC Class Codes: G01G 19/086 wherein the vehicle mass is dynamically estimated
• CPC Class Codes: G01G 9/00 Methods of, or apparatus for, the determination of weight, not provided for in groups G01G1/00 - G01G7/00

Abstract

A method for determining the mass of a body is described. The method comprises the application and measurement of a first motive force to the body to move the body in a first state of motion. The acceleration of the body is also measured at this time. This methodology is repeated for a second state of motion. The measured motive forces and accelerations are then used to calculate the mass, and hence the weight of the body. An accelerometer may be employed to measure the accelerations. The methods may be adapted so as to correct for the angle θ of the ground across which the body is moved and or the tilt angle α of the accelerometer relative to the ground. The methods may employ a novel surface angle measuring device that does not require contact with the ground and which does not require the body to be stationary.

Claims

1. A method for determining the mass of an aircraft, the method comprising:

applying and measuring a first motive force to the aircraft to move the aircraft in a first state of motion across an area of ground;

employing an accelerometer mounted on the aircraft to measure a first acceleration of the aircraft when in the first state of motion;

correcting the measurement of the first acceleration for a tilt angle α

of the accelerometer relative to the ground;

applying and measuring a second motive force to the aircraft to move the aircraft in a second state of motion;

measuring a second acceleration of the aircraft when in the second state of motion;

measuring the angle of inclination θ

between the area of ground and a true gravity horizontal; and

calculating the mass of the aircraft from the measured first and second motive forces, the measured first and second accelerations, and the measured angle of inclination θ

.

2. A method for determining the mass of an aircraft as claimed in claim 1 wherein the second motive force moves the body across an area of ground.

3. A method for determining the mass of an aircraft as claimed in claim 1 wherein the measurement of the first motive force is corrected for the angle θ

between the area of ground and the true gravity horizontal.

4. A method for determining the mass of an aircraft as claimed in claim 1 wherein the measurement of the second motive force is corrected for the angle θ

between the area of ground and the true gravity horizontal.

5. A method for determining the mass of an aircraft as claimed in claim 1 wherein the second acceleration is measured by an accelerometer mounted on the aircraft.

6. A method for determining the mass of an aircraft as claimed in claim 5 wherein the measurement of the second acceleration is corrected for the tilt angle α

of the accelerometer relative to the ground.

7. A method for determining the mass of an aircraft as claimed in claim 1 wherein the first state of motion comprises a state of steady motion.

8. A method for determining the mass of an aircraft as claimed in claim 1 wherein the first state of motion comprises a state of acceleration.

9. A method for determining the mass of an aircraft as claimed in claim 1 wherein the second state of motion comprises a state of steady motion.

10. A method for determining the mass of an aircraft as claimed in claim 1 wherein the second state of motion comprises a state of acceleration.

11. A method for determining the mass of an aircraft as claimed in claim 1 wherein the first motive force is applied by setting a thrust of an engine of the aircraft.

12. A method for determining the mass of an aircraft as claimed in claim 1 wherein the second motive force is applied by setting a thrust of an engine of the aircraft.

13. A method of calculating the thrust required for an aircraft take-off, the method comprising the determination of the mass of the aircraft in accordance with the method as defined by claim 1.

15. A method of calculating the flight path of an aircraft, the method comprising the determination of the mass of the aircraft in accordance with the method as defined claim 1.

14. A method of calculating the fuel requirements for an aircraft journey, the method comprising the determination of the mass of the aircraft in accordance with the method as defined by 1.

16. An inertial mass system for determining the mass of an aircraft, the inertial mass system comprising an accelerometer for measuring the acceleration of the aircraft over an area of ground, a surface angle measuring device for measuring the angle of inclination θ

between the area of ground and a true gravity horizontal, and a processor configured to calculate the mass of the aircraft based on;

a measured value of a first motive force applied to the aircraft to move the aircraft in a first state of motion;

a measured value of a first acceleration of the aircraft when in the first state of motion, wherein the measured value of the first acceleration is corrected for a tilt angle α

of the accelerometer relative to the ground;

a measured value of a second motive force applied to the aircraft to move the aircraft in a second state of motion;

a measured value of a second acceleration of the aircraft when in the second state of motion; and

the angle of inclination θ

between the area of ground and the true gravity horizontal.

17. An inertial mass system as claimed in claim 16 wherein the inertial mass system further comprises an interface that provides a means of communication between the inertial mass system and an aircraft flight management system.

18. An inertial mass system as claimed in claim 17 wherein the first and second motive forces applied to the body are measured by an engine management system of the flight management system.

19. An inertial mass system as claimed in claim 16 wherein the accelerometer comprises a tilt sensor.

20. An inertial mass system as claimed in claim 16 wherein the inertial mass system further comprises a surface angle measuring device.

21. An inertial mass system as claimed in claim 20 wherein the surface angle measuring device comprising a chassis that defines first and second rangefinder measuring positions, the first and second rangefinder measuring positions being rotationally separated by an angle φ

;

a first rangefinder and a first inclinometer.

22. An inertial mass system as claimed in claim 21 wherein the chassis provides a means for mounting the surface angle measuring device on the aircraft.

23. An inertial mass system as claimed in claim 21 wherein the first rangefinder is located at the first rangefinder position.

24. An inertial mass system as claimed in claim 21 wherein a second rangefinder is located at the second rangefinder position.

25. An inertial mass system as claimed in claim 21 wherein the inclinometer is positioned having a horizontal axis perpendicular to a line bisecting the angle φ

between the first and second rangefinders.

26. An inertial mass system as claimed in claim 21 wherein the first inclinometer is fixed to the first rangefinder.

27. An inertial mass system as claimed in claim 26 wherein the surface angle measuring device further comprises a second inclinometer fixed to the second rangefinder.

28. An inertial mass system as claimed in claim 21 wherein the first rangefinder is pivotally mounted to provide rotational movement between the first and second rangefinder measuring positions.

29. An inertial mass system as claimed in claim 28 wherein the first inclinometer is fixed to the first rangefinder.

30. An inertial mass system as claimed in claim 21 wherein the first rangefinder comprises a laser rangefinder.

31. An inertial mass system as claimed in claim 24 wherein the first rangefinder comprises a laser rangefinder.

32. A flight management system for an aircraft comprising an inertial mass system as claimed in claim 16.

33. An aircraft comprising a flight management system as claimed in claim 32.