Robot control system for window cleaning

Window cleaning is a two-stage process; application of cleaning fluid, which is usually achieved by using a wetted applicator and removal of cleaning fluid by a squeegee blade without spillage on to other areas of the facade or previously cleaned areas of glass. This is particularly difficult for example if the window is located on the roof of a building and cleaning is performed from inside by the human window cleaner. Simulation studies were conducted to demonstrate the feasibility of a robot system to act and mimic the human operator; an end effector had to be designed to accommodate different tools such as applicator and squeegee; the pay load for tool handling, sensory feedback requirements; force and compliance control; and finally the cost of the overall system had to be feasible. As a result of the studies it was conceived that the end effector should contain a combined datuming/cleaning head. This arrangement would allow automatic datuming and location of the window pane relative to the robot using a specially designed and constructed compliant head. One advantage of a combined head being the elimination of tool changes between the datuming and wiping operation. A dedicated XYZR robot system was designed which makes use of an Industrial IBM PC connected to a DELTA-7AV systems PMAC card to drive the robot and to: coordinate its actions with those of the OCS roof mounted gantry delivery carrier system.