US Patent 9443992 Solar panel autonomous cleaning device

Described herein is an autonomous cleaning device for a solar panel. The device includes a cleaning member mounted for unidirectional movement or bidirectional movement over the solar panel. The cleaning member has a first cleaning portion for cleaning the solar panel as the cleaning member moves in one direction and a second cleaning portion for cleaning the solar panel as the cleaning member moves in the other direction. The cleaning portions are respectively brought into contact with the solar panel by axial rotation of the cleaning member about a restricted path of travel.