Patent ID: 7643133
Filing Date: 2010-01-05
Classification: B65G

Abstract:
1. A method of detecting motion of an unit load device in a cargo hold of an aircraft, comprising: providing a floor of the cargo hold of an aircraft with a power drive unit having a motor, at least one driver roller element coupled to said motor, a light source, a light detector, and a processor having a memory associated therewith for storing instructions; emitting, with the light source, a plurality of pulses of light in a direction of an underside of an unit load device, when an unit load device is over the power drive unit; detecting, with the light detector, light reflected from the underside of the unit load device; sampling the detected light to form a time series of digital samples, each digital sample representative of an intensity of reflected light; and performing calculations on a plurality of said digital samples to determine whether the unit load device is moving, wherein: said calculations include at least one from the group consisting of: (a) determining the number of spikes among the digital samples; and (b) taking at least one statistic of the digital samples and comparing said at least one statistic with a corresponding at least one threshold.