Semi-Autonomous System for Lakes and Rivers Depollution

The purpose of this paper is to outline the development of a robust and low-cost semi-autonomous, remotely operated unmanned surface vessel (USV) used as a platform for environmental remediation technologies. By defining the shape as a catamaran, the first practical purpose is to build the collection mechanism in form of a cage to collect floating waste from rivers and lakes - in particular, plastic recipients that accumulate at the surface of the water. The unit was named “GreenCat” deriving from the purpose and the shape. Preliminary hull shape numerical investigation studies enabled carefully managed manufacturing processes resulting in a reduced manufacturing time. Based on hydrodynamic numerical simulations it is suggested that 6 km/h is an optimal travel speed. The electronic equipment was fitted and tested using two different controllers, manoeuvred by using both a radio command and a touch screen. Full-scale tests showed an autonomy of more than 60 minutes on one LiFePO04 - 12.8V-50Ah accumulator. The hull was designed to fit several accumulators making it possible to increase the autonomy to an estimated 8 hours. The data collected from the LiDAR system provided key information for the next level of autonomy, where obstacles can be avoided and the USV can charge automatically in a charging dock.