Power drive unit with unit load device sensor

• US 7,402,973 B2
• Filed: 02/21/2007
• Issued: 07/22/2008
• Est. Priority Date: 12/13/2005
• Status: Expired due to Fees

• Current Assignee: Goodrich Corporation (Rtx Corporation)
• Original Assignee: Goodrich Corporation (Rtx Corporation)
• Inventors: Hettwer, Peter Nicholas
• Primary Examiner(s): Ro; Bentsu
• Application Number:
  US11/677,284
• Publication Number:
  US 20070138343A1
• Time in Patent Office: 517 Days
• Field of Search: 318/480, 318/563, 318/640, 244/117.R, 244/118.1, 244/118.2, 244/137.1, 198/780, 198/781.01, 198/781.02, 198/781.08
• US Class Current: 318/563
• CPC Class Codes: B64D 9/00 Equipment for handling freight; Equipment for facilitating passenger embarkation or the like emergency equipment B64D17/00, B64D19/00, B64D25/00; structures integral with fuselage to facilitate loading, fuselage floors specially adapted for freight, steps mounted on and retractable within aircraft B64C; ground installations B64F

Abstract

A cargo power drive unit includes a motor and at least one drive roller element coupled to the motor. The power drive unit further includes a light transmitter for emitting light and a light receiver for measuring light. The power drive unit measures an amount of ambient light and then measures an amount of total light after the light transmitter emits light. The power drive unit then determines whether a cargo container is present based on a calculation of reflected light and the measurement of ambient light.

Claims

1. A method of detecting scrubbing of a drive roller element by a cargo power drive unit to which the drive roller element belongs, comprising:

calculating a length of time a cargo container is present above a cargo power drive unit;

determining if a motor of the cargo power drive unit is running; and

determining if the drive roller element is scrubbing based on said calculated length of time and said determination of whether the motor is running.

2. The method of claim 1, wherein said calculating the length of time the cargo container is present, is based at least in part on light reflected from an underside of said cargo container.

3. The method of claim 1, wherein said calculating the length of time the cargo container is present comprises:

measuring an ambient light at a light receiver;

emitting light at a light transmitter;

measuring a combined reflected light and ambient light at the light receiver;

calculating a reflected light; and

determining the presence of a cargo container based on said calculation of reflected light.

4. The method of claim 3, wherein said calculating the reflected light comprises:

measuring a combined reflected and ambient light when emitting light at the light transmitter; and

calculating an amount of reflected light that is returned from said cargo container by subtracting the ambient light measurement from the combined light measurement.

5. The method of claim 1, further comprising:

removing power from the drive roller element of the cargo power drive unit if it is determined that the drive roller element is scrubbing.

6. A computer readable medium having instructions stored thereon that, when executed by a processor, cause the processor to:

calculate a length of time a cargo container is present at a cargo power drive unit;

determine if a motor of the cargo power drive unit is running; and

determine if at least one drive roller element of the cargo power drive unit is scrubbing based on said calculated length of time and said determination of whether the motor is running.

7. The computer readable medium of claim 6, said instructions causing said processor to calculate the length of time the cargo container is present based at least in part on light reflected from an underside of said cargo container.

8. The computer readable medium of claim 7, said instructions further causing said processor to:

remove power from the drive roller element of the cargo power drive unit if it is determined that said drive roller element is scrubbing.

9. The computer readable medium of claim 6, said instructions causing said processor to calculate the length of time the cargo container is present by:

measuring an ambient light at a light receiver;

emitting light at a light transmitter;

measuring a combined reflected light and ambient light at the light receiver;

calculating a reflected light; and

determining the presence of a cargo container based on the calculation of reflected light.

10. The computer readable medium of claim 9, said instructions causing said processor to calculate the reflected light by:

measuring a total light when transmitting light at the light transmitter; and

calculating an amount of reflected light that is returned from said cargo container by subtracting the ambient light from the combined reflected and ambient light.