| 摘要 |
A cargo power drive unit 28 in an aircraft cargo deck includes a motor, at least one driver roller element 51, 52 coupled to the motor, a light transmitter 57 and a light receiver 58 for measuring light, the unit determines whether a cargo container is present based on a calculation of reflected light and the measurement of ambient light. The reflected light may be calculated by comparing measurements with the light transmitter turned off and on. The light transmitter may be a light emitting diode emitting infra red light and the receiver may be a photo transistor. The unit may further determine if the roller is scrubbing based whether the motor is running and on the length of time a container is present compared to the time a container is expected to be present given the size of containers and the speed of driving by the power drive unit. The unit may remove power from the motor if scrubbing is detected. |
