Window cleaning system with water circulation for building façade maintenance robot and its efficiency analysis

Most maintenance works on building exterior walls are carried out by human labor and a cable-driven system (gondola). This approach involves a safety problem, motivating many recent studies of exterior wall automated maintenance methods. However, the conventional studies have been concentrated only on moving mechanism and the studies on cleaning method and processing of cleaning materials are insufficient. In addition, most conventional automated systems are composed of a roll-brush and injection nozzle. These systems generate problems such as the scattering and dripping of used water resulting contamination of surrounding areas. In order to solve these problems, a new cleaning tool system with water circulation function is developed to improve cleaning efficiency and reduce water usage in this paper. Using the cleaning tool system with the water circulation (injection-squeeze-suctioncollection-filtering-recharge) and Pulse Width Modulation (PWM) flow control, the scattering and dripping was removed and the water usage was reduced about 20%. Also, this cleaning tool system was compared to manual work by human experts as well as previously developed automated (or semi-automated) cleaning robots through statistical analysis.