Experimental comparison of drag-wiper and roller-wiper glass-cleaning robots
Most window cleaning robots use a drag wiper. This is a fixed wiper that only moves when the robot moves. An alternative is a roller wiper, which is a wiper attached to a roller that is being rotated by a motor. The paper tries to answer the question which solution is best. It turns out that a roller wiper creates less friction that the robot needs to overcome, causing it to be more energy efficient. During the tests, the roller wiper robot used only half the energy the drag wiper used. Furthermore, the roller wiper requires less adsorption force that the drag wiper to operate safely. The roller wiper is also much better at removing dirt that is hard to remove. It is, however, less safe when it comes to touching the frame of a window. A drag wiper will simply bump into the frame, but a roller wiper will create a force that is pulling the robot away from the glass, increasing the chance of vacuum leaks.