US Patent 9402524 Debris detecting unit and robot cleaning device having the same

A robot cleaning device includes a debris detecting unit. The robot cleaning device includes a body, a driving unit to enable the body to travel, a drum brush unit provided at the body, to sweep up debris, using a brush and a rotating drum, a debris box to store the debris swept up by the drum brush unit, a debris detecting unit to detect whether debris has been introduced into the debris box through the drum brush unit during a cleaning operation, and a controller to determine whether debris is introduced into the debris box and whether debris has been accumulated in the debris box in a predetermined amount, based on introduction or non-introduction of debris detected by the debris detecting unit.