Autonomous robot for cleaning photovoltaic panels in desert zones

In desert zones, a continuous cleaning activity of photovoltaic panels in solar plants is required since the depo- sition of both airborne dust and sand after a storm can reduce their efficiency up to 80%. Manual cleaning of the photovoltaic panels in dry areas is costly, cannot make use of water and workers must be employed several times in a month, often under extreme environmental conditions. For all these reasons, the research of cleaning solutions performed by autonomous robotic systems are seen beneficial to recover the solar panels efficiency at reasonable costs also nightly. In this respect, this paper presents the implementation of an unmanned low-cost robotic device operating without rails or guides for waterless dust and sand removal from the surface of pho- tovoltaic panels. The robot autonomously moves as a half-track and gently wipes the dust away by means of a couple of independent helical brushes that alternatively rotate, according to a defined combination of the cleaning and motion strategy. Moreover, in real-time the robot detects its spatial position by ultrasonic sensors, regulates both its speed rate and motion direction. The on-board control system, based on an ARDUINO DUE platform, settles the robot travel direction, its speed and which brush must be activated for cleaning. Experimental tests have been performed by fabricating a prototype of the device to assess its effectiveness and reliability in terms of the autonomous motion, dust removal and low power consumption.